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WSL2-Linux-Kernel/arch/arm64/kvm/pmu-emul.c

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treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 234 Based on 1 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license version 2 as published by the free software foundation this program is distributed in the hope that it will be useful but without any warranty without even the implied warranty of merchantability or fitness for a particular purpose see the gnu general public license for more details you should have received a copy of the gnu general public license along with this program if not see http www gnu org licenses extracted by the scancode license scanner the SPDX license identifier GPL-2.0-only has been chosen to replace the boilerplate/reference in 503 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Alexios Zavras <alexios.zavras@intel.com> Reviewed-by: Allison Randal <allison@lohutok.net> Reviewed-by: Enrico Weigelt <info@metux.net> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190602204653.811534538@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-06-03 08:44:50 +03:00
// SPDX-License-Identifier: GPL-2.0-only
arm64: KVM: Add access handler for event counter register These kind of registers include PMEVCNTRn, PMCCNTR and PMXEVCNTR which is mapped to PMEVCNTRn. The access handler translates all aarch32 register offsets to aarch64 ones and uses vcpu_sys_reg() to access their values to avoid taking care of big endian. When reading these registers, return the sum of register value and the value perf event counts. Signed-off-by: Shannon Zhao <shannon.zhao@linaro.org> Reviewed-by: Andrew Jones <drjones@redhat.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-12-08 10:29:06 +03:00
/*
* Copyright (C) 2015 Linaro Ltd.
* Author: Shannon Zhao <shannon.zhao@linaro.org>
*/
#include <linux/cpu.h>
#include <linux/kvm.h>
#include <linux/kvm_host.h>
KVM: arm64: Keep a list of probed PMUs The ARM PMU driver calls kvm_host_pmu_init() after probing to tell KVM that a hardware PMU is available for guest emulation. Heterogeneous systems can have more than one PMU present, and the callback gets called multiple times, once for each of them. Keep track of all the PMUs available to KVM, as they're going to be needed later. Reviewed-by: Reiji Watanabe <reijiw@google.com> Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20220127161759.53553-5-alexandru.elisei@arm.com
2022-01-27 19:17:57 +03:00
#include <linux/list.h>
arm64: KVM: Add access handler for event counter register These kind of registers include PMEVCNTRn, PMCCNTR and PMXEVCNTR which is mapped to PMEVCNTRn. The access handler translates all aarch32 register offsets to aarch64 ones and uses vcpu_sys_reg() to access their values to avoid taking care of big endian. When reading these registers, return the sum of register value and the value perf event counts. Signed-off-by: Shannon Zhao <shannon.zhao@linaro.org> Reviewed-by: Andrew Jones <drjones@redhat.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-12-08 10:29:06 +03:00
#include <linux/perf_event.h>
KVM: arm64: pmu: Reset sample period on overflow handling The PMU emulation code uses the perf event sample period to trigger the overflow detection. This works fine for the *first* overflow handling, but results in a huge number of interrupts on the host, unrelated to the number of interrupts handled in the guest (a x20 factor is pretty common for the cycle counter). On a slow system (such as a SW model), this can result in the guest only making forward progress at a glacial pace. It turns out that the clue is in the name. The sample period is exactly that: a period. And once the an overflow has occured, the following period should be the full width of the associated counter, instead of whatever the guest had initially programed. Reset the sample period to the architected value in the overflow handler, which now results in a number of host interrupts that is much closer to the number of interrupts in the guest. Fixes: b02386eb7dac ("arm64: KVM: Add PMU overflow interrupt routing") Reviewed-by: Andrew Murray <andrew.murray@arm.com> Signed-off-by: Marc Zyngier <maz@kernel.org>
2019-10-06 12:28:50 +03:00
#include <linux/perf/arm_pmu.h>
arm64: KVM: Add a new vcpu device control group for PMUv3 To configure the virtual PMUv3 overflow interrupt number, we use the vcpu kvm_device ioctl, encapsulating the KVM_ARM_VCPU_PMU_V3_IRQ attribute within the KVM_ARM_VCPU_PMU_V3_CTRL group. After configuring the PMUv3, call the vcpu ioctl with attribute KVM_ARM_VCPU_PMU_V3_INIT to initialize the PMUv3. Signed-off-by: Shannon Zhao <shannon.zhao@linaro.org> Acked-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Andrew Jones <drjones@redhat.com> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2016-01-11 16:35:32 +03:00
#include <linux/uaccess.h>
arm64: KVM: Add access handler for event counter register These kind of registers include PMEVCNTRn, PMCCNTR and PMXEVCNTR which is mapped to PMEVCNTRn. The access handler translates all aarch32 register offsets to aarch64 ones and uses vcpu_sys_reg() to access their values to avoid taking care of big endian. When reading these registers, return the sum of register value and the value perf event counts. Signed-off-by: Shannon Zhao <shannon.zhao@linaro.org> Reviewed-by: Andrew Jones <drjones@redhat.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-12-08 10:29:06 +03:00
#include <asm/kvm_emulate.h>
#include <kvm/arm_pmu.h>
arm64: KVM: Add PMU overflow interrupt routing When calling perf_event_create_kernel_counter to create perf_event, assign a overflow handler. Then when the perf event overflows, set the corresponding bit of guest PMOVSSET register. If this counter is enabled and its interrupt is enabled as well, kick the vcpu to sync the interrupt. On VM entry, if there is counter overflowed and interrupt level is changed, inject the interrupt with corresponding level. On VM exit, sync the interrupt level as well if it has been changed. Signed-off-by: Shannon Zhao <shannon.zhao@linaro.org> Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> Reviewed-by: Andrew Jones <drjones@redhat.com> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2016-02-26 14:29:19 +03:00
#include <kvm/arm_vgic.h>
arm64: KVM: Add access handler for event counter register These kind of registers include PMEVCNTRn, PMCCNTR and PMXEVCNTR which is mapped to PMEVCNTRn. The access handler translates all aarch32 register offsets to aarch64 ones and uses vcpu_sys_reg() to access their values to avoid taking care of big endian. When reading these registers, return the sum of register value and the value perf event counts. Signed-off-by: Shannon Zhao <shannon.zhao@linaro.org> Reviewed-by: Andrew Jones <drjones@redhat.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-12-08 10:29:06 +03:00
KVM: arm64: PMU: Align chained counter implementation with architecture pseudocode Ricardo recently pointed out that the PMU chained counter emulation in KVM wasn't quite behaving like the one on actual hardware, in the sense that a chained counter would expose an overflow on both halves of a chained counter, while KVM would only expose the overflow on the top half. The difference is subtle, but significant. What does the architecture say (DDI0087 H.a): - Up to PMUv3p4, all counters but the cycle counter are 32bit - A 32bit counter that overflows generates a CHAIN event on the adjacent counter after exposing its own overflow status - The CHAIN event is accounted if the counter is correctly configured (CHAIN event selected and counter enabled) This all means that our current implementation (which uses 64bit perf events) prevents us from emulating this overflow on the lower half. How to fix this? By implementing the above, to the letter. This largely results in code deletion, removing the notions of "counter pair", "chained counters", and "canonical counter". The code is further restructured to make the CHAIN handling similar to SWINC, as the two are now extremely similar in behaviour. Reported-by: Ricardo Koller <ricarkol@google.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Reviewed-by: Reiji Watanabe <reijiw@google.com> Link: https://lore.kernel.org/r/20221113163832.3154370-3-maz@kernel.org
2022-11-13 19:38:18 +03:00
#define PERF_ATTR_CFG1_COUNTER_64BIT BIT(0)
KVM: arm64: Hide kvm_arm_pmu_available behind CONFIG_HW_PERF_EVENTS=y Move the definition of kvm_arm_pmu_available to pmu-emul.c and, out of "necessity", hide it behind CONFIG_HW_PERF_EVENTS. Provide a stub for the key's wrapper, kvm_arm_support_pmu_v3(). Moving the key's definition out of perf.c will allow a future commit to delete perf.c entirely. Signed-off-by: Sean Christopherson <seanjc@google.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lore.kernel.org/r/20211111020738.2512932-16-seanjc@google.com
2021-11-11 05:07:36 +03:00
DEFINE_STATIC_KEY_FALSE(kvm_arm_pmu_available);
KVM: arm64: Keep a list of probed PMUs The ARM PMU driver calls kvm_host_pmu_init() after probing to tell KVM that a hardware PMU is available for guest emulation. Heterogeneous systems can have more than one PMU present, and the callback gets called multiple times, once for each of them. Keep track of all the PMUs available to KVM, as they're going to be needed later. Reviewed-by: Reiji Watanabe <reijiw@google.com> Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20220127161759.53553-5-alexandru.elisei@arm.com
2022-01-27 19:17:57 +03:00
static LIST_HEAD(arm_pmus);
static DEFINE_MUTEX(arm_pmus_lock);
KVM: arm64: PMU: Make kvm_pmc the main data structure The PMU code has historically been torn between referencing a counter as a pair vcpu+index or as the PMC pointer. Given that it is pretty easy to go from one representation to the other, standardise on the latter which, IMHO, makes the code slightly more readable. YMMV. Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221113163832.3154370-17-maz@kernel.org
2022-11-13 19:38:32 +03:00
static void kvm_pmu_create_perf_event(struct kvm_pmc *pmc);
KVM: arm64: PMU: Simplify setting a counter to a specific value kvm_pmu_set_counter_value() is pretty odd, as it tries to update the counter value while taking into account the value that is currently held by the running perf counter. This is not only complicated, this is quite wrong. Nowhere in the architecture is it said that the counter would be offset by something that is pending. The counter should be updated with the value set by SW, and start counting from there if required. Remove the odd computation and just assign the provided value after having released the perf event (which is then restarted). Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221113163832.3154370-9-maz@kernel.org
2022-11-13 19:38:24 +03:00
static void kvm_pmu_release_perf_event(struct kvm_pmc *pmc);
KVM: arm/arm64: Support chained PMU counters ARMv8 provides support for chained PMU counters, where an event type of 0x001E is set for odd-numbered counters, the event counter will increment by one for each overflow of the preceding even-numbered counter. Let's emulate this in KVM by creating a 64 bit perf counter when a user chains two emulated counters together. For chained events we only support generating an overflow interrupt on the high counter. We use the attributes of the low counter to determine the attributes of the perf event. Suggested-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Andrew Murray <andrew.murray@arm.com> Reviewed-by: Julien Thierry <julien.thierry@arm.com> Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2019-06-17 22:01:05 +03:00
KVM: arm64: PMU: Make kvm_pmc the main data structure The PMU code has historically been torn between referencing a counter as a pair vcpu+index or as the PMC pointer. Given that it is pretty easy to go from one representation to the other, standardise on the latter which, IMHO, makes the code slightly more readable. YMMV. Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221113163832.3154370-17-maz@kernel.org
2022-11-13 19:38:32 +03:00
static struct kvm_vcpu *kvm_pmc_to_vcpu(const struct kvm_pmc *pmc)
{
return container_of(pmc, struct kvm_vcpu, arch.pmu.pmc[pmc->idx]);
}
static struct kvm_pmc *kvm_vcpu_idx_to_pmc(struct kvm_vcpu *vcpu, int cnt_idx)
{
return &vcpu->arch.pmu.pmc[cnt_idx];
}
KVM: arm64: Use event mask matching architecture revision The PMU code suffers from a small defect where we assume that the event number provided by the guest is always 16 bit wide, even if the CPU only implements the ARMv8.0 architecture. This isn't really problematic in the sense that the event number ends up in a system register, cropping it to the right width, but still this needs fixing. In order to make it work, let's probe the version of the PMU that the guest is going to use. This is done by temporarily creating a kernel event and looking at the PMUVer field that has been saved at probe time in the associated arm_pmu structure. This in turn gets saved in the kvm structure, and subsequently used to compute the event mask that gets used throughout the PMU code. Signed-off-by: Marc Zyngier <maz@kernel.org>
2020-03-17 14:11:56 +03:00
static u32 kvm_pmu_event_mask(struct kvm *kvm)
{
KVM: arm64: Keep a per-VM pointer to the default PMU As we are about to allow selection of the PMU exposed to a guest, start by keeping track of the default one instead of only the PMU version. Signed-off-by: Marc Zyngier <maz@kernel.org> Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com> Link: https://lore.kernel.org/r/20220127161759.53553-4-alexandru.elisei@arm.com
2022-01-27 19:17:56 +03:00
unsigned int pmuver;
pmuver = kvm->arch.arm_pmu->pmuver;
switch (pmuver) {
arm64/sysreg: Use feature numbering for PMU and SPE revisions Currently the kernel refers to the versions of the PMU and SPE features by the version of the architecture where those features were updated but the ARM refers to them using the FEAT_ names for the features. To improve consistency and help with updating for newer features and since v9 will make our current naming scheme a bit more confusing update the macros identfying features to use the FEAT_ based scheme. Signed-off-by: Mark Brown <broonie@kernel.org> Link: https://lore.kernel.org/r/20220910163354.860255-4-broonie@kernel.org Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2022-09-10 19:33:51 +03:00
case ID_AA64DFR0_EL1_PMUVer_IMP:
KVM: arm64: Use event mask matching architecture revision The PMU code suffers from a small defect where we assume that the event number provided by the guest is always 16 bit wide, even if the CPU only implements the ARMv8.0 architecture. This isn't really problematic in the sense that the event number ends up in a system register, cropping it to the right width, but still this needs fixing. In order to make it work, let's probe the version of the PMU that the guest is going to use. This is done by temporarily creating a kernel event and looking at the PMUVer field that has been saved at probe time in the associated arm_pmu structure. This in turn gets saved in the kvm structure, and subsequently used to compute the event mask that gets used throughout the PMU code. Signed-off-by: Marc Zyngier <maz@kernel.org>
2020-03-17 14:11:56 +03:00
return GENMASK(9, 0);
arm64/sysreg: Use feature numbering for PMU and SPE revisions Currently the kernel refers to the versions of the PMU and SPE features by the version of the architecture where those features were updated but the ARM refers to them using the FEAT_ names for the features. To improve consistency and help with updating for newer features and since v9 will make our current naming scheme a bit more confusing update the macros identfying features to use the FEAT_ based scheme. Signed-off-by: Mark Brown <broonie@kernel.org> Link: https://lore.kernel.org/r/20220910163354.860255-4-broonie@kernel.org Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2022-09-10 19:33:51 +03:00
case ID_AA64DFR0_EL1_PMUVer_V3P1:
case ID_AA64DFR0_EL1_PMUVer_V3P4:
case ID_AA64DFR0_EL1_PMUVer_V3P5:
case ID_AA64DFR0_EL1_PMUVer_V3P7:
KVM: arm64: Use event mask matching architecture revision The PMU code suffers from a small defect where we assume that the event number provided by the guest is always 16 bit wide, even if the CPU only implements the ARMv8.0 architecture. This isn't really problematic in the sense that the event number ends up in a system register, cropping it to the right width, but still this needs fixing. In order to make it work, let's probe the version of the PMU that the guest is going to use. This is done by temporarily creating a kernel event and looking at the PMUVer field that has been saved at probe time in the associated arm_pmu structure. This in turn gets saved in the kvm structure, and subsequently used to compute the event mask that gets used throughout the PMU code. Signed-off-by: Marc Zyngier <maz@kernel.org>
2020-03-17 14:11:56 +03:00
return GENMASK(15, 0);
default: /* Shouldn't be here, just for sanity */
KVM: arm64: Keep a per-VM pointer to the default PMU As we are about to allow selection of the PMU exposed to a guest, start by keeping track of the default one instead of only the PMU version. Signed-off-by: Marc Zyngier <maz@kernel.org> Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com> Link: https://lore.kernel.org/r/20220127161759.53553-4-alexandru.elisei@arm.com
2022-01-27 19:17:56 +03:00
WARN_ONCE(1, "Unknown PMU version %d\n", pmuver);
KVM: arm64: Use event mask matching architecture revision The PMU code suffers from a small defect where we assume that the event number provided by the guest is always 16 bit wide, even if the CPU only implements the ARMv8.0 architecture. This isn't really problematic in the sense that the event number ends up in a system register, cropping it to the right width, but still this needs fixing. In order to make it work, let's probe the version of the PMU that the guest is going to use. This is done by temporarily creating a kernel event and looking at the PMUVer field that has been saved at probe time in the associated arm_pmu structure. This in turn gets saved in the kvm structure, and subsequently used to compute the event mask that gets used throughout the PMU code. Signed-off-by: Marc Zyngier <maz@kernel.org>
2020-03-17 14:11:56 +03:00
return 0;
}
}
KVM: arm/arm64: Remove pmc->bitmask We currently use pmc->bitmask to determine the width of the pmc - however it's superfluous as the pmc index already describes if the pmc is a cycle counter or event counter. The architecture clearly describes the widths of these counters. Let's remove the bitmask to simplify the code. Signed-off-by: Andrew Murray <andrew.murray@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2019-06-17 22:01:04 +03:00
/**
KVM: arm64: PMU: Make kvm_pmc the main data structure The PMU code has historically been torn between referencing a counter as a pair vcpu+index or as the PMC pointer. Given that it is pretty easy to go from one representation to the other, standardise on the latter which, IMHO, makes the code slightly more readable. YMMV. Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221113163832.3154370-17-maz@kernel.org
2022-11-13 19:38:32 +03:00
* kvm_pmc_is_64bit - determine if counter is 64bit
* @pmc: counter context
KVM: arm/arm64: Remove pmc->bitmask We currently use pmc->bitmask to determine the width of the pmc - however it's superfluous as the pmc index already describes if the pmc is a cycle counter or event counter. The architecture clearly describes the widths of these counters. Let's remove the bitmask to simplify the code. Signed-off-by: Andrew Murray <andrew.murray@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2019-06-17 22:01:04 +03:00
*/
KVM: arm64: PMU: Make kvm_pmc the main data structure The PMU code has historically been torn between referencing a counter as a pair vcpu+index or as the PMC pointer. Given that it is pretty easy to go from one representation to the other, standardise on the latter which, IMHO, makes the code slightly more readable. YMMV. Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221113163832.3154370-17-maz@kernel.org
2022-11-13 19:38:32 +03:00
static bool kvm_pmc_is_64bit(struct kvm_pmc *pmc)
KVM: arm64: PMU: Distinguish between 64bit counter and 64bit overflow The PMU architecture makes a subtle difference between a 64bit counter and a counter that has a 64bit overflow. This is for example the case of the cycle counter, which can generate an overflow on a 32bit boundary if PMCR_EL0.LC==0 despite the accumulation being done on 64 bits. Use this distinction in the few cases where it matters in the code, as we will reuse this with PMUv3p5 long counters. Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221113163832.3154370-5-maz@kernel.org
2022-11-13 19:38:20 +03:00
{
KVM: arm64: PMU: Make kvm_pmc the main data structure The PMU code has historically been torn between referencing a counter as a pair vcpu+index or as the PMC pointer. Given that it is pretty easy to go from one representation to the other, standardise on the latter which, IMHO, makes the code slightly more readable. YMMV. Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221113163832.3154370-17-maz@kernel.org
2022-11-13 19:38:32 +03:00
return (pmc->idx == ARMV8_PMU_CYCLE_IDX ||
kvm_pmu_is_3p5(kvm_pmc_to_vcpu(pmc)));
KVM: arm64: PMU: Distinguish between 64bit counter and 64bit overflow The PMU architecture makes a subtle difference between a 64bit counter and a counter that has a 64bit overflow. This is for example the case of the cycle counter, which can generate an overflow on a 32bit boundary if PMCR_EL0.LC==0 despite the accumulation being done on 64 bits. Use this distinction in the few cases where it matters in the code, as we will reuse this with PMUv3p5 long counters. Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221113163832.3154370-5-maz@kernel.org
2022-11-13 19:38:20 +03:00
}
KVM: arm64: PMU: Make kvm_pmc the main data structure The PMU code has historically been torn between referencing a counter as a pair vcpu+index or as the PMC pointer. Given that it is pretty easy to go from one representation to the other, standardise on the latter which, IMHO, makes the code slightly more readable. YMMV. Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221113163832.3154370-17-maz@kernel.org
2022-11-13 19:38:32 +03:00
static bool kvm_pmc_has_64bit_overflow(struct kvm_pmc *pmc)
KVM: arm/arm64: Remove pmc->bitmask We currently use pmc->bitmask to determine the width of the pmc - however it's superfluous as the pmc index already describes if the pmc is a cycle counter or event counter. The architecture clearly describes the widths of these counters. Let's remove the bitmask to simplify the code. Signed-off-by: Andrew Murray <andrew.murray@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2019-06-17 22:01:04 +03:00
{
KVM: arm64: PMU: Make kvm_pmc the main data structure The PMU code has historically been torn between referencing a counter as a pair vcpu+index or as the PMC pointer. Given that it is pretty easy to go from one representation to the other, standardise on the latter which, IMHO, makes the code slightly more readable. YMMV. Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221113163832.3154370-17-maz@kernel.org
2022-11-13 19:38:32 +03:00
u64 val = __vcpu_sys_reg(kvm_pmc_to_vcpu(pmc), PMCR_EL0);
KVM: arm64: PMU: Implement PMUv3p5 long counter support PMUv3p5 (which is mandatory with ARMv8.5) comes with some extra features: - All counters are 64bit - The overflow point is controlled by the PMCR_EL0.LP bit Add the required checks in the helpers that control counter width and overflow, as well as the sysreg handling for the LP bit. A new kvm_pmu_is_3p5() helper makes it easy to spot the PMUv3p5 specific handling. Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221113163832.3154370-14-maz@kernel.org
2022-11-13 19:38:29 +03:00
KVM: arm64: PMU: Make kvm_pmc the main data structure The PMU code has historically been torn between referencing a counter as a pair vcpu+index or as the PMC pointer. Given that it is pretty easy to go from one representation to the other, standardise on the latter which, IMHO, makes the code slightly more readable. YMMV. Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221113163832.3154370-17-maz@kernel.org
2022-11-13 19:38:32 +03:00
return (pmc->idx < ARMV8_PMU_CYCLE_IDX && (val & ARMV8_PMU_PMCR_LP)) ||
(pmc->idx == ARMV8_PMU_CYCLE_IDX && (val & ARMV8_PMU_PMCR_LC));
KVM: arm/arm64: Remove pmc->bitmask We currently use pmc->bitmask to determine the width of the pmc - however it's superfluous as the pmc index already describes if the pmc is a cycle counter or event counter. The architecture clearly describes the widths of these counters. Let's remove the bitmask to simplify the code. Signed-off-by: Andrew Murray <andrew.murray@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2019-06-17 22:01:04 +03:00
}
KVM: arm64: PMU: Make kvm_pmc the main data structure The PMU code has historically been torn between referencing a counter as a pair vcpu+index or as the PMC pointer. Given that it is pretty easy to go from one representation to the other, standardise on the latter which, IMHO, makes the code slightly more readable. YMMV. Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221113163832.3154370-17-maz@kernel.org
2022-11-13 19:38:32 +03:00
static bool kvm_pmu_counter_can_chain(struct kvm_pmc *pmc)
KVM: arm64: PMU: Align chained counter implementation with architecture pseudocode Ricardo recently pointed out that the PMU chained counter emulation in KVM wasn't quite behaving like the one on actual hardware, in the sense that a chained counter would expose an overflow on both halves of a chained counter, while KVM would only expose the overflow on the top half. The difference is subtle, but significant. What does the architecture say (DDI0087 H.a): - Up to PMUv3p4, all counters but the cycle counter are 32bit - A 32bit counter that overflows generates a CHAIN event on the adjacent counter after exposing its own overflow status - The CHAIN event is accounted if the counter is correctly configured (CHAIN event selected and counter enabled) This all means that our current implementation (which uses 64bit perf events) prevents us from emulating this overflow on the lower half. How to fix this? By implementing the above, to the letter. This largely results in code deletion, removing the notions of "counter pair", "chained counters", and "canonical counter". The code is further restructured to make the CHAIN handling similar to SWINC, as the two are now extremely similar in behaviour. Reported-by: Ricardo Koller <ricarkol@google.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Reviewed-by: Reiji Watanabe <reijiw@google.com> Link: https://lore.kernel.org/r/20221113163832.3154370-3-maz@kernel.org
2022-11-13 19:38:18 +03:00
{
KVM: arm64: PMU: Make kvm_pmc the main data structure The PMU code has historically been torn between referencing a counter as a pair vcpu+index or as the PMC pointer. Given that it is pretty easy to go from one representation to the other, standardise on the latter which, IMHO, makes the code slightly more readable. YMMV. Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221113163832.3154370-17-maz@kernel.org
2022-11-13 19:38:32 +03:00
return (!(pmc->idx & 1) && (pmc->idx + 1) < ARMV8_PMU_CYCLE_IDX &&
!kvm_pmc_has_64bit_overflow(pmc));
KVM: arm/arm64: Support chained PMU counters ARMv8 provides support for chained PMU counters, where an event type of 0x001E is set for odd-numbered counters, the event counter will increment by one for each overflow of the preceding even-numbered counter. Let's emulate this in KVM by creating a 64 bit perf counter when a user chains two emulated counters together. For chained events we only support generating an overflow interrupt on the high counter. We use the attributes of the low counter to determine the attributes of the perf event. Suggested-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Andrew Murray <andrew.murray@arm.com> Reviewed-by: Julien Thierry <julien.thierry@arm.com> Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2019-06-17 22:01:05 +03:00
}
KVM: arm64: PMU: Add counter_index_to_*reg() helpers In order to reduce the boilerplate code, add two helpers returning the counter register index (resp. the event register) in the vcpu register file from the counter index. Reviewed-by: Oliver Upton <oliver.upton@linux.dev> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221113163832.3154370-8-maz@kernel.org
2022-11-13 19:38:23 +03:00
static u32 counter_index_to_reg(u64 idx)
{
return (idx == ARMV8_PMU_CYCLE_IDX) ? PMCCNTR_EL0 : PMEVCNTR0_EL0 + idx;
}
static u32 counter_index_to_evtreg(u64 idx)
{
return (idx == ARMV8_PMU_CYCLE_IDX) ? PMCCFILTR_EL0 : PMEVTYPER0_EL0 + idx;
}
KVM: arm64: PMU: Make kvm_pmc the main data structure The PMU code has historically been torn between referencing a counter as a pair vcpu+index or as the PMC pointer. Given that it is pretty easy to go from one representation to the other, standardise on the latter which, IMHO, makes the code slightly more readable. YMMV. Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221113163832.3154370-17-maz@kernel.org
2022-11-13 19:38:32 +03:00
static u64 kvm_pmu_get_pmc_value(struct kvm_pmc *pmc)
KVM: arm/arm64: Support chained PMU counters ARMv8 provides support for chained PMU counters, where an event type of 0x001E is set for odd-numbered counters, the event counter will increment by one for each overflow of the preceding even-numbered counter. Let's emulate this in KVM by creating a 64 bit perf counter when a user chains two emulated counters together. For chained events we only support generating an overflow interrupt on the high counter. We use the attributes of the low counter to determine the attributes of the perf event. Suggested-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Andrew Murray <andrew.murray@arm.com> Reviewed-by: Julien Thierry <julien.thierry@arm.com> Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2019-06-17 22:01:05 +03:00
{
KVM: arm64: PMU: Make kvm_pmc the main data structure The PMU code has historically been torn between referencing a counter as a pair vcpu+index or as the PMC pointer. Given that it is pretty easy to go from one representation to the other, standardise on the latter which, IMHO, makes the code slightly more readable. YMMV. Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221113163832.3154370-17-maz@kernel.org
2022-11-13 19:38:32 +03:00
struct kvm_vcpu *vcpu = kvm_pmc_to_vcpu(pmc);
KVM: arm64: PMU: Align chained counter implementation with architecture pseudocode Ricardo recently pointed out that the PMU chained counter emulation in KVM wasn't quite behaving like the one on actual hardware, in the sense that a chained counter would expose an overflow on both halves of a chained counter, while KVM would only expose the overflow on the top half. The difference is subtle, but significant. What does the architecture say (DDI0087 H.a): - Up to PMUv3p4, all counters but the cycle counter are 32bit - A 32bit counter that overflows generates a CHAIN event on the adjacent counter after exposing its own overflow status - The CHAIN event is accounted if the counter is correctly configured (CHAIN event selected and counter enabled) This all means that our current implementation (which uses 64bit perf events) prevents us from emulating this overflow on the lower half. How to fix this? By implementing the above, to the letter. This largely results in code deletion, removing the notions of "counter pair", "chained counters", and "canonical counter". The code is further restructured to make the CHAIN handling similar to SWINC, as the two are now extremely similar in behaviour. Reported-by: Ricardo Koller <ricarkol@google.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Reviewed-by: Reiji Watanabe <reijiw@google.com> Link: https://lore.kernel.org/r/20221113163832.3154370-3-maz@kernel.org
2022-11-13 19:38:18 +03:00
u64 counter, reg, enabled, running;
KVM: arm/arm64: Support chained PMU counters ARMv8 provides support for chained PMU counters, where an event type of 0x001E is set for odd-numbered counters, the event counter will increment by one for each overflow of the preceding even-numbered counter. Let's emulate this in KVM by creating a 64 bit perf counter when a user chains two emulated counters together. For chained events we only support generating an overflow interrupt on the high counter. We use the attributes of the low counter to determine the attributes of the perf event. Suggested-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Andrew Murray <andrew.murray@arm.com> Reviewed-by: Julien Thierry <julien.thierry@arm.com> Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2019-06-17 22:01:05 +03:00
KVM: arm64: PMU: Make kvm_pmc the main data structure The PMU code has historically been torn between referencing a counter as a pair vcpu+index or as the PMC pointer. Given that it is pretty easy to go from one representation to the other, standardise on the latter which, IMHO, makes the code slightly more readable. YMMV. Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221113163832.3154370-17-maz@kernel.org
2022-11-13 19:38:32 +03:00
reg = counter_index_to_reg(pmc->idx);
KVM: arm64: PMU: Align chained counter implementation with architecture pseudocode Ricardo recently pointed out that the PMU chained counter emulation in KVM wasn't quite behaving like the one on actual hardware, in the sense that a chained counter would expose an overflow on both halves of a chained counter, while KVM would only expose the overflow on the top half. The difference is subtle, but significant. What does the architecture say (DDI0087 H.a): - Up to PMUv3p4, all counters but the cycle counter are 32bit - A 32bit counter that overflows generates a CHAIN event on the adjacent counter after exposing its own overflow status - The CHAIN event is accounted if the counter is correctly configured (CHAIN event selected and counter enabled) This all means that our current implementation (which uses 64bit perf events) prevents us from emulating this overflow on the lower half. How to fix this? By implementing the above, to the letter. This largely results in code deletion, removing the notions of "counter pair", "chained counters", and "canonical counter". The code is further restructured to make the CHAIN handling similar to SWINC, as the two are now extremely similar in behaviour. Reported-by: Ricardo Koller <ricarkol@google.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Reviewed-by: Reiji Watanabe <reijiw@google.com> Link: https://lore.kernel.org/r/20221113163832.3154370-3-maz@kernel.org
2022-11-13 19:38:18 +03:00
counter = __vcpu_sys_reg(vcpu, reg);
KVM: arm/arm64: Support chained PMU counters ARMv8 provides support for chained PMU counters, where an event type of 0x001E is set for odd-numbered counters, the event counter will increment by one for each overflow of the preceding even-numbered counter. Let's emulate this in KVM by creating a 64 bit perf counter when a user chains two emulated counters together. For chained events we only support generating an overflow interrupt on the high counter. We use the attributes of the low counter to determine the attributes of the perf event. Suggested-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Andrew Murray <andrew.murray@arm.com> Reviewed-by: Julien Thierry <julien.thierry@arm.com> Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2019-06-17 22:01:05 +03:00
/*
* The real counter value is equal to the value of counter register plus
arm64: KVM: Add access handler for event counter register These kind of registers include PMEVCNTRn, PMCCNTR and PMXEVCNTR which is mapped to PMEVCNTRn. The access handler translates all aarch32 register offsets to aarch64 ones and uses vcpu_sys_reg() to access their values to avoid taking care of big endian. When reading these registers, return the sum of register value and the value perf event counts. Signed-off-by: Shannon Zhao <shannon.zhao@linaro.org> Reviewed-by: Andrew Jones <drjones@redhat.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-12-08 10:29:06 +03:00
* the value perf event counts.
*/
if (pmc->perf_event)
counter += perf_event_read_value(pmc->perf_event, &enabled,
&running);
KVM: arm64: PMU: Make kvm_pmc the main data structure The PMU code has historically been torn between referencing a counter as a pair vcpu+index or as the PMC pointer. Given that it is pretty easy to go from one representation to the other, standardise on the latter which, IMHO, makes the code slightly more readable. YMMV. Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221113163832.3154370-17-maz@kernel.org
2022-11-13 19:38:32 +03:00
if (!kvm_pmc_is_64bit(pmc))
KVM: arm/arm64: Remove pmc->bitmask We currently use pmc->bitmask to determine the width of the pmc - however it's superfluous as the pmc index already describes if the pmc is a cycle counter or event counter. The architecture clearly describes the widths of these counters. Let's remove the bitmask to simplify the code. Signed-off-by: Andrew Murray <andrew.murray@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2019-06-17 22:01:04 +03:00
counter = lower_32_bits(counter);
return counter;
arm64: KVM: Add access handler for event counter register These kind of registers include PMEVCNTRn, PMCCNTR and PMXEVCNTR which is mapped to PMEVCNTRn. The access handler translates all aarch32 register offsets to aarch64 ones and uses vcpu_sys_reg() to access their values to avoid taking care of big endian. When reading these registers, return the sum of register value and the value perf event counts. Signed-off-by: Shannon Zhao <shannon.zhao@linaro.org> Reviewed-by: Andrew Jones <drjones@redhat.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-12-08 10:29:06 +03:00
}
KVM: arm64: PMU: Make kvm_pmc the main data structure The PMU code has historically been torn between referencing a counter as a pair vcpu+index or as the PMC pointer. Given that it is pretty easy to go from one representation to the other, standardise on the latter which, IMHO, makes the code slightly more readable. YMMV. Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221113163832.3154370-17-maz@kernel.org
2022-11-13 19:38:32 +03:00
/**
* kvm_pmu_get_counter_value - get PMU counter value
* @vcpu: The vcpu pointer
* @select_idx: The counter index
*/
u64 kvm_pmu_get_counter_value(struct kvm_vcpu *vcpu, u64 select_idx)
arm64: KVM: Add access handler for event counter register These kind of registers include PMEVCNTRn, PMCCNTR and PMXEVCNTR which is mapped to PMEVCNTRn. The access handler translates all aarch32 register offsets to aarch64 ones and uses vcpu_sys_reg() to access their values to avoid taking care of big endian. When reading these registers, return the sum of register value and the value perf event counts. Signed-off-by: Shannon Zhao <shannon.zhao@linaro.org> Reviewed-by: Andrew Jones <drjones@redhat.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-12-08 10:29:06 +03:00
{
KVM/arm64: Don't emulate a PMU for 32-bit guests if feature not set kvm->arch.arm_pmu is set when userspace attempts to set the first PMU attribute. As certain attributes are mandatory, arm_pmu ends up always being set to a valid arm_pmu, otherwise KVM will refuse to run the VCPU. However, this only happens if the VCPU has the PMU feature. If the VCPU doesn't have the feature bit set, kvm->arch.arm_pmu will be left uninitialized and equal to NULL. KVM doesn't do ID register emulation for 32-bit guests and accesses to the PMU registers aren't gated by the pmu_visibility() function. This is done to prevent injecting unexpected undefined exceptions in guests which have detected the presence of a hardware PMU. But even though the VCPU feature is missing, KVM still attempts to emulate certain aspects of the PMU when PMU registers are accessed. This leads to a NULL pointer dereference like this one, which happens on an odroid-c4 board when running the kvm-unit-tests pmu-cycle-counter test with kvmtool and without the PMU feature being set: [ 454.402699] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000150 [ 454.405865] Mem abort info: [ 454.408596] ESR = 0x96000004 [ 454.411638] EC = 0x25: DABT (current EL), IL = 32 bits [ 454.416901] SET = 0, FnV = 0 [ 454.419909] EA = 0, S1PTW = 0 [ 454.423010] FSC = 0x04: level 0 translation fault [ 454.427841] Data abort info: [ 454.430687] ISV = 0, ISS = 0x00000004 [ 454.434484] CM = 0, WnR = 0 [ 454.437404] user pgtable: 4k pages, 48-bit VAs, pgdp=000000000c924000 [ 454.443800] [0000000000000150] pgd=0000000000000000, p4d=0000000000000000 [ 454.450528] Internal error: Oops: 96000004 [#1] PREEMPT SMP [ 454.456036] Modules linked in: [ 454.459053] CPU: 1 PID: 267 Comm: kvm-vcpu-0 Not tainted 5.18.0-rc4 #113 [ 454.465697] Hardware name: Hardkernel ODROID-C4 (DT) [ 454.470612] pstate: 60400009 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) [ 454.477512] pc : kvm_pmu_event_mask.isra.0+0x14/0x74 [ 454.482427] lr : kvm_pmu_set_counter_event_type+0x2c/0x80 [ 454.487775] sp : ffff80000a9839c0 [ 454.491050] x29: ffff80000a9839c0 x28: ffff000000a83a00 x27: 0000000000000000 [ 454.498127] x26: 0000000000000000 x25: 0000000000000000 x24: ffff00000a510000 [ 454.505198] x23: ffff000000a83a00 x22: ffff000003b01000 x21: 0000000000000000 [ 454.512271] x20: 000000000000001f x19: 00000000000003ff x18: 0000000000000000 [ 454.519343] x17: 000000008003fe98 x16: 0000000000000000 x15: 0000000000000000 [ 454.526416] x14: 0000000000000000 x13: 0000000000000000 x12: 0000000000000000 [ 454.533489] x11: 000000008003fdbc x10: 0000000000009d20 x9 : 000000000000001b [ 454.540561] x8 : 0000000000000000 x7 : 0000000000000d00 x6 : 0000000000009d00 [ 454.547633] x5 : 0000000000000037 x4 : 0000000000009d00 x3 : 0d09000000000000 [ 454.554705] x2 : 000000000000001f x1 : 0000000000000000 x0 : 0000000000000000 [ 454.561779] Call trace: [ 454.564191] kvm_pmu_event_mask.isra.0+0x14/0x74 [ 454.568764] kvm_pmu_set_counter_event_type+0x2c/0x80 [ 454.573766] access_pmu_evtyper+0x128/0x170 [ 454.577905] perform_access+0x34/0x80 [ 454.581527] kvm_handle_cp_32+0x13c/0x160 [ 454.585495] kvm_handle_cp15_32+0x1c/0x30 [ 454.589462] handle_exit+0x70/0x180 [ 454.592912] kvm_arch_vcpu_ioctl_run+0x1c4/0x5e0 [ 454.597485] kvm_vcpu_ioctl+0x23c/0x940 [ 454.601280] __arm64_sys_ioctl+0xa8/0xf0 [ 454.605160] invoke_syscall+0x48/0x114 [ 454.608869] el0_svc_common.constprop.0+0xd4/0xfc [ 454.613527] do_el0_svc+0x28/0x90 [ 454.616803] el0_svc+0x34/0xb0 [ 454.619822] el0t_64_sync_handler+0xa4/0x130 [ 454.624049] el0t_64_sync+0x18c/0x190 [ 454.627675] Code: a9be7bfd 910003fd f9000bf3 52807ff3 (b9415001) [ 454.633714] ---[ end trace 0000000000000000 ]--- In this particular case, Linux hasn't detected the presence of a hardware PMU because the PMU node is missing from the DTB, so userspace would have been unable to set the VCPU PMU feature even if it attempted it. What happens is that the 32-bit guest reads ID_DFR0, which advertises the presence of the PMU, and when it tries to program a counter, it triggers the NULL pointer dereference because kvm->arch.arm_pmu is NULL. kvm-arch.arm_pmu was introduced by commit 46b187821472 ("KVM: arm64: Keep a per-VM pointer to the default PMU"). Until that commit, this error would be triggered instead: [ 73.388140] ------------[ cut here ]------------ [ 73.388189] Unknown PMU version 0 [ 73.390420] WARNING: CPU: 1 PID: 264 at arch/arm64/kvm/pmu-emul.c:36 kvm_pmu_event_mask.isra.0+0x6c/0x74 [ 73.399821] Modules linked in: [ 73.402835] CPU: 1 PID: 264 Comm: kvm-vcpu-0 Not tainted 5.17.0 #114 [ 73.409132] Hardware name: Hardkernel ODROID-C4 (DT) [ 73.414048] pstate: 60400009 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) [ 73.420948] pc : kvm_pmu_event_mask.isra.0+0x6c/0x74 [ 73.425863] lr : kvm_pmu_event_mask.isra.0+0x6c/0x74 [ 73.430779] sp : ffff80000a8db9b0 [ 73.434055] x29: ffff80000a8db9b0 x28: ffff000000dbaac0 x27: 0000000000000000 [ 73.441131] x26: ffff000000dbaac0 x25: 00000000c600000d x24: 0000000000180720 [ 73.448203] x23: ffff800009ffbe10 x22: ffff00000b612000 x21: 0000000000000000 [ 73.455276] x20: 000000000000001f x19: 0000000000000000 x18: ffffffffffffffff [ 73.462348] x17: 000000008003fe98 x16: 0000000000000000 x15: 0720072007200720 [ 73.469420] x14: 0720072007200720 x13: ffff800009d32488 x12: 00000000000004e6 [ 73.476493] x11: 00000000000001a2 x10: ffff800009d32488 x9 : ffff800009d32488 [ 73.483565] x8 : 00000000ffffefff x7 : ffff800009d8a488 x6 : ffff800009d8a488 [ 73.490638] x5 : ffff0000f461a9d8 x4 : 0000000000000000 x3 : 0000000000000001 [ 73.497710] x2 : 0000000000000000 x1 : 0000000000000000 x0 : ffff000000dbaac0 [ 73.504784] Call trace: [ 73.507195] kvm_pmu_event_mask.isra.0+0x6c/0x74 [ 73.511768] kvm_pmu_set_counter_event_type+0x2c/0x80 [ 73.516770] access_pmu_evtyper+0x128/0x16c [ 73.520910] perform_access+0x34/0x80 [ 73.524532] kvm_handle_cp_32+0x13c/0x160 [ 73.528500] kvm_handle_cp15_32+0x1c/0x30 [ 73.532467] handle_exit+0x70/0x180 [ 73.535917] kvm_arch_vcpu_ioctl_run+0x20c/0x6e0 [ 73.540489] kvm_vcpu_ioctl+0x2b8/0x9e0 [ 73.544283] __arm64_sys_ioctl+0xa8/0xf0 [ 73.548165] invoke_syscall+0x48/0x114 [ 73.551874] el0_svc_common.constprop.0+0xd4/0xfc [ 73.556531] do_el0_svc+0x28/0x90 [ 73.559808] el0_svc+0x28/0x80 [ 73.562826] el0t_64_sync_handler+0xa4/0x130 [ 73.567054] el0t_64_sync+0x1a0/0x1a4 [ 73.570676] ---[ end trace 0000000000000000 ]--- [ 73.575382] kvm: pmu event creation failed -2 The root cause remains the same: kvm->arch.pmuver was never set to something sensible because the VCPU feature itself was never set. The odroid-c4 is somewhat of a special case, because Linux doesn't probe the PMU. But the above errors can easily be reproduced on any hardware, with or without a PMU driver, as long as userspace doesn't set the PMU feature. Work around the fact that KVM advertises a PMU even when the VCPU feature is not set by gating all PMU emulation on the feature. The guest can still access the registers without KVM injecting an undefined exception. Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20220425145530.723858-1-alexandru.elisei@arm.com
2022-04-25 17:55:30 +03:00
if (!kvm_vcpu_has_pmu(vcpu))
KVM: arm64: PMU: Make kvm_pmc the main data structure The PMU code has historically been torn between referencing a counter as a pair vcpu+index or as the PMC pointer. Given that it is pretty easy to go from one representation to the other, standardise on the latter which, IMHO, makes the code slightly more readable. YMMV. Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221113163832.3154370-17-maz@kernel.org
2022-11-13 19:38:32 +03:00
return 0;
KVM/arm64: Don't emulate a PMU for 32-bit guests if feature not set kvm->arch.arm_pmu is set when userspace attempts to set the first PMU attribute. As certain attributes are mandatory, arm_pmu ends up always being set to a valid arm_pmu, otherwise KVM will refuse to run the VCPU. However, this only happens if the VCPU has the PMU feature. If the VCPU doesn't have the feature bit set, kvm->arch.arm_pmu will be left uninitialized and equal to NULL. KVM doesn't do ID register emulation for 32-bit guests and accesses to the PMU registers aren't gated by the pmu_visibility() function. This is done to prevent injecting unexpected undefined exceptions in guests which have detected the presence of a hardware PMU. But even though the VCPU feature is missing, KVM still attempts to emulate certain aspects of the PMU when PMU registers are accessed. This leads to a NULL pointer dereference like this one, which happens on an odroid-c4 board when running the kvm-unit-tests pmu-cycle-counter test with kvmtool and without the PMU feature being set: [ 454.402699] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000150 [ 454.405865] Mem abort info: [ 454.408596] ESR = 0x96000004 [ 454.411638] EC = 0x25: DABT (current EL), IL = 32 bits [ 454.416901] SET = 0, FnV = 0 [ 454.419909] EA = 0, S1PTW = 0 [ 454.423010] FSC = 0x04: level 0 translation fault [ 454.427841] Data abort info: [ 454.430687] ISV = 0, ISS = 0x00000004 [ 454.434484] CM = 0, WnR = 0 [ 454.437404] user pgtable: 4k pages, 48-bit VAs, pgdp=000000000c924000 [ 454.443800] [0000000000000150] pgd=0000000000000000, p4d=0000000000000000 [ 454.450528] Internal error: Oops: 96000004 [#1] PREEMPT SMP [ 454.456036] Modules linked in: [ 454.459053] CPU: 1 PID: 267 Comm: kvm-vcpu-0 Not tainted 5.18.0-rc4 #113 [ 454.465697] Hardware name: Hardkernel ODROID-C4 (DT) [ 454.470612] pstate: 60400009 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) [ 454.477512] pc : kvm_pmu_event_mask.isra.0+0x14/0x74 [ 454.482427] lr : kvm_pmu_set_counter_event_type+0x2c/0x80 [ 454.487775] sp : ffff80000a9839c0 [ 454.491050] x29: ffff80000a9839c0 x28: ffff000000a83a00 x27: 0000000000000000 [ 454.498127] x26: 0000000000000000 x25: 0000000000000000 x24: ffff00000a510000 [ 454.505198] x23: ffff000000a83a00 x22: ffff000003b01000 x21: 0000000000000000 [ 454.512271] x20: 000000000000001f x19: 00000000000003ff x18: 0000000000000000 [ 454.519343] x17: 000000008003fe98 x16: 0000000000000000 x15: 0000000000000000 [ 454.526416] x14: 0000000000000000 x13: 0000000000000000 x12: 0000000000000000 [ 454.533489] x11: 000000008003fdbc x10: 0000000000009d20 x9 : 000000000000001b [ 454.540561] x8 : 0000000000000000 x7 : 0000000000000d00 x6 : 0000000000009d00 [ 454.547633] x5 : 0000000000000037 x4 : 0000000000009d00 x3 : 0d09000000000000 [ 454.554705] x2 : 000000000000001f x1 : 0000000000000000 x0 : 0000000000000000 [ 454.561779] Call trace: [ 454.564191] kvm_pmu_event_mask.isra.0+0x14/0x74 [ 454.568764] kvm_pmu_set_counter_event_type+0x2c/0x80 [ 454.573766] access_pmu_evtyper+0x128/0x170 [ 454.577905] perform_access+0x34/0x80 [ 454.581527] kvm_handle_cp_32+0x13c/0x160 [ 454.585495] kvm_handle_cp15_32+0x1c/0x30 [ 454.589462] handle_exit+0x70/0x180 [ 454.592912] kvm_arch_vcpu_ioctl_run+0x1c4/0x5e0 [ 454.597485] kvm_vcpu_ioctl+0x23c/0x940 [ 454.601280] __arm64_sys_ioctl+0xa8/0xf0 [ 454.605160] invoke_syscall+0x48/0x114 [ 454.608869] el0_svc_common.constprop.0+0xd4/0xfc [ 454.613527] do_el0_svc+0x28/0x90 [ 454.616803] el0_svc+0x34/0xb0 [ 454.619822] el0t_64_sync_handler+0xa4/0x130 [ 454.624049] el0t_64_sync+0x18c/0x190 [ 454.627675] Code: a9be7bfd 910003fd f9000bf3 52807ff3 (b9415001) [ 454.633714] ---[ end trace 0000000000000000 ]--- In this particular case, Linux hasn't detected the presence of a hardware PMU because the PMU node is missing from the DTB, so userspace would have been unable to set the VCPU PMU feature even if it attempted it. What happens is that the 32-bit guest reads ID_DFR0, which advertises the presence of the PMU, and when it tries to program a counter, it triggers the NULL pointer dereference because kvm->arch.arm_pmu is NULL. kvm-arch.arm_pmu was introduced by commit 46b187821472 ("KVM: arm64: Keep a per-VM pointer to the default PMU"). Until that commit, this error would be triggered instead: [ 73.388140] ------------[ cut here ]------------ [ 73.388189] Unknown PMU version 0 [ 73.390420] WARNING: CPU: 1 PID: 264 at arch/arm64/kvm/pmu-emul.c:36 kvm_pmu_event_mask.isra.0+0x6c/0x74 [ 73.399821] Modules linked in: [ 73.402835] CPU: 1 PID: 264 Comm: kvm-vcpu-0 Not tainted 5.17.0 #114 [ 73.409132] Hardware name: Hardkernel ODROID-C4 (DT) [ 73.414048] pstate: 60400009 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) [ 73.420948] pc : kvm_pmu_event_mask.isra.0+0x6c/0x74 [ 73.425863] lr : kvm_pmu_event_mask.isra.0+0x6c/0x74 [ 73.430779] sp : ffff80000a8db9b0 [ 73.434055] x29: ffff80000a8db9b0 x28: ffff000000dbaac0 x27: 0000000000000000 [ 73.441131] x26: ffff000000dbaac0 x25: 00000000c600000d x24: 0000000000180720 [ 73.448203] x23: ffff800009ffbe10 x22: ffff00000b612000 x21: 0000000000000000 [ 73.455276] x20: 000000000000001f x19: 0000000000000000 x18: ffffffffffffffff [ 73.462348] x17: 000000008003fe98 x16: 0000000000000000 x15: 0720072007200720 [ 73.469420] x14: 0720072007200720 x13: ffff800009d32488 x12: 00000000000004e6 [ 73.476493] x11: 00000000000001a2 x10: ffff800009d32488 x9 : ffff800009d32488 [ 73.483565] x8 : 00000000ffffefff x7 : ffff800009d8a488 x6 : ffff800009d8a488 [ 73.490638] x5 : ffff0000f461a9d8 x4 : 0000000000000000 x3 : 0000000000000001 [ 73.497710] x2 : 0000000000000000 x1 : 0000000000000000 x0 : ffff000000dbaac0 [ 73.504784] Call trace: [ 73.507195] kvm_pmu_event_mask.isra.0+0x6c/0x74 [ 73.511768] kvm_pmu_set_counter_event_type+0x2c/0x80 [ 73.516770] access_pmu_evtyper+0x128/0x16c [ 73.520910] perform_access+0x34/0x80 [ 73.524532] kvm_handle_cp_32+0x13c/0x160 [ 73.528500] kvm_handle_cp15_32+0x1c/0x30 [ 73.532467] handle_exit+0x70/0x180 [ 73.535917] kvm_arch_vcpu_ioctl_run+0x20c/0x6e0 [ 73.540489] kvm_vcpu_ioctl+0x2b8/0x9e0 [ 73.544283] __arm64_sys_ioctl+0xa8/0xf0 [ 73.548165] invoke_syscall+0x48/0x114 [ 73.551874] el0_svc_common.constprop.0+0xd4/0xfc [ 73.556531] do_el0_svc+0x28/0x90 [ 73.559808] el0_svc+0x28/0x80 [ 73.562826] el0t_64_sync_handler+0xa4/0x130 [ 73.567054] el0t_64_sync+0x1a0/0x1a4 [ 73.570676] ---[ end trace 0000000000000000 ]--- [ 73.575382] kvm: pmu event creation failed -2 The root cause remains the same: kvm->arch.pmuver was never set to something sensible because the VCPU feature itself was never set. The odroid-c4 is somewhat of a special case, because Linux doesn't probe the PMU. But the above errors can easily be reproduced on any hardware, with or without a PMU driver, as long as userspace doesn't set the PMU feature. Work around the fact that KVM advertises a PMU even when the VCPU feature is not set by gating all PMU emulation on the feature. The guest can still access the registers without KVM injecting an undefined exception. Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20220425145530.723858-1-alexandru.elisei@arm.com
2022-04-25 17:55:30 +03:00
KVM: arm64: PMU: Make kvm_pmc the main data structure The PMU code has historically been torn between referencing a counter as a pair vcpu+index or as the PMC pointer. Given that it is pretty easy to go from one representation to the other, standardise on the latter which, IMHO, makes the code slightly more readable. YMMV. Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221113163832.3154370-17-maz@kernel.org
2022-11-13 19:38:32 +03:00
return kvm_pmu_get_pmc_value(kvm_vcpu_idx_to_pmc(vcpu, select_idx));
}
KVM: arm64: PMU: Simplify setting a counter to a specific value kvm_pmu_set_counter_value() is pretty odd, as it tries to update the counter value while taking into account the value that is currently held by the running perf counter. This is not only complicated, this is quite wrong. Nowhere in the architecture is it said that the counter would be offset by something that is pending. The counter should be updated with the value set by SW, and start counting from there if required. Remove the odd computation and just assign the provided value after having released the perf event (which is then restarted). Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221113163832.3154370-9-maz@kernel.org
2022-11-13 19:38:24 +03:00
KVM: arm64: PMU: Make kvm_pmc the main data structure The PMU code has historically been torn between referencing a counter as a pair vcpu+index or as the PMC pointer. Given that it is pretty easy to go from one representation to the other, standardise on the latter which, IMHO, makes the code slightly more readable. YMMV. Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221113163832.3154370-17-maz@kernel.org
2022-11-13 19:38:32 +03:00
static void kvm_pmu_set_pmc_value(struct kvm_pmc *pmc, u64 val, bool force)
{
struct kvm_vcpu *vcpu = kvm_pmc_to_vcpu(pmc);
u64 reg;
KVM: arm64: PMU: Do not let AArch32 change the counters' top 32 bits Even when using PMUv3p5 (which implies 64bit counters), there is no way for AArch32 to write to the top 32 bits of the counters. The only way to influence these bits (other than by counting events) is by writing PMCR.P==1. Make sure we obey the architecture and preserve the top 32 bits on a counter update. Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221113163832.3154370-10-maz@kernel.org
2022-11-13 19:38:25 +03:00
KVM: arm64: PMU: Make kvm_pmc the main data structure The PMU code has historically been torn between referencing a counter as a pair vcpu+index or as the PMC pointer. Given that it is pretty easy to go from one representation to the other, standardise on the latter which, IMHO, makes the code slightly more readable. YMMV. Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221113163832.3154370-17-maz@kernel.org
2022-11-13 19:38:32 +03:00
kvm_pmu_release_perf_event(pmc);
reg = counter_index_to_reg(pmc->idx);
if (vcpu_mode_is_32bit(vcpu) && pmc->idx != ARMV8_PMU_CYCLE_IDX &&
KVM: arm64: PMU: Do not let AArch32 change the counters' top 32 bits Even when using PMUv3p5 (which implies 64bit counters), there is no way for AArch32 to write to the top 32 bits of the counters. The only way to influence these bits (other than by counting events) is by writing PMCR.P==1. Make sure we obey the architecture and preserve the top 32 bits on a counter update. Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221113163832.3154370-10-maz@kernel.org
2022-11-13 19:38:25 +03:00
!force) {
/*
* Even with PMUv3p5, AArch32 cannot write to the top
* 32bit of the counters. The only possible course of
* action is to use PMCR.P, which will reset them to
* 0 (the only use of the 'force' parameter).
*/
val = __vcpu_sys_reg(vcpu, reg) & GENMASK(63, 32);
val |= lower_32_bits(val);
}
KVM: arm64: PMU: Simplify setting a counter to a specific value kvm_pmu_set_counter_value() is pretty odd, as it tries to update the counter value while taking into account the value that is currently held by the running perf counter. This is not only complicated, this is quite wrong. Nowhere in the architecture is it said that the counter would be offset by something that is pending. The counter should be updated with the value set by SW, and start counting from there if required. Remove the odd computation and just assign the provided value after having released the perf event (which is then restarted). Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221113163832.3154370-9-maz@kernel.org
2022-11-13 19:38:24 +03:00
__vcpu_sys_reg(vcpu, reg) = val;
KVM: arm/arm64: Re-create event when setting counter value The perf event sample_period is currently set based upon the current counter value, when PMXEVTYPER is written to and the perf event is created. However the user may choose to write the type before the counter value in which case sample_period will be set incorrectly. Let's instead decouple event creation from PMXEVTYPER and (re)create the event in either suitation. Signed-off-by: Andrew Murray <andrew.murray@arm.com> Reviewed-by: Julien Thierry <julien.thierry@arm.com> Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2019-06-17 22:01:03 +03:00
/* Recreate the perf event to reflect the updated sample_period */
KVM: arm64: PMU: Make kvm_pmc the main data structure The PMU code has historically been torn between referencing a counter as a pair vcpu+index or as the PMC pointer. Given that it is pretty easy to go from one representation to the other, standardise on the latter which, IMHO, makes the code slightly more readable. YMMV. Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221113163832.3154370-17-maz@kernel.org
2022-11-13 19:38:32 +03:00
kvm_pmu_create_perf_event(pmc);
arm64: KVM: Add access handler for event counter register These kind of registers include PMEVCNTRn, PMCCNTR and PMXEVCNTR which is mapped to PMEVCNTRn. The access handler translates all aarch32 register offsets to aarch64 ones and uses vcpu_sys_reg() to access their values to avoid taking care of big endian. When reading these registers, return the sum of register value and the value perf event counts. Signed-off-by: Shannon Zhao <shannon.zhao@linaro.org> Reviewed-by: Andrew Jones <drjones@redhat.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-12-08 10:29:06 +03:00
}
arm64: KVM: Add access handler for PMCNTENSET and PMCNTENCLR register Since the reset value of PMCNTENSET and PMCNTENCLR is UNKNOWN, use reset_unknown for its reset handler. Add a handler to emulate writing PMCNTENSET or PMCNTENCLR register. When writing to PMCNTENSET, call perf_event_enable to enable the perf event. When writing to PMCNTENCLR, call perf_event_disable to disable the perf event. Signed-off-by: Shannon Zhao <shannon.zhao@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-09-08 07:26:13 +03:00
KVM: arm64: PMU: Do not let AArch32 change the counters' top 32 bits Even when using PMUv3p5 (which implies 64bit counters), there is no way for AArch32 to write to the top 32 bits of the counters. The only way to influence these bits (other than by counting events) is by writing PMCR.P==1. Make sure we obey the architecture and preserve the top 32 bits on a counter update. Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221113163832.3154370-10-maz@kernel.org
2022-11-13 19:38:25 +03:00
/**
* kvm_pmu_set_counter_value - set PMU counter value
* @vcpu: The vcpu pointer
* @select_idx: The counter index
* @val: The counter value
*/
void kvm_pmu_set_counter_value(struct kvm_vcpu *vcpu, u64 select_idx, u64 val)
{
KVM: arm64: PMU: Make kvm_pmc the main data structure The PMU code has historically been torn between referencing a counter as a pair vcpu+index or as the PMC pointer. Given that it is pretty easy to go from one representation to the other, standardise on the latter which, IMHO, makes the code slightly more readable. YMMV. Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221113163832.3154370-17-maz@kernel.org
2022-11-13 19:38:32 +03:00
if (!kvm_vcpu_has_pmu(vcpu))
return;
kvm_pmu_set_pmc_value(kvm_vcpu_idx_to_pmc(vcpu, select_idx), val, false);
KVM: arm64: PMU: Do not let AArch32 change the counters' top 32 bits Even when using PMUv3p5 (which implies 64bit counters), there is no way for AArch32 to write to the top 32 bits of the counters. The only way to influence these bits (other than by counting events) is by writing PMCR.P==1. Make sure we obey the architecture and preserve the top 32 bits on a counter update. Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221113163832.3154370-10-maz@kernel.org
2022-11-13 19:38:25 +03:00
}
KVM: arm/arm64: Extract duplicated code to own function Let's reduce code duplication by extracting common code to its own function. Signed-off-by: Andrew Murray <andrew.murray@arm.com> Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2019-06-17 22:01:02 +03:00
/**
* kvm_pmu_release_perf_event - remove the perf event
* @pmc: The PMU counter pointer
*/
static void kvm_pmu_release_perf_event(struct kvm_pmc *pmc)
{
if (pmc->perf_event) {
perf_event_disable(pmc->perf_event);
perf_event_release_kernel(pmc->perf_event);
pmc->perf_event = NULL;
}
}
arm64: KVM: PMU: Add perf event map and introduce perf event creating function When we use tools like perf on host, perf passes the event type and the id of this event type category to kernel, then kernel will map them to hardware event number and write this number to PMU PMEVTYPER<n>_EL0 register. When getting the event number in KVM, directly use raw event type to create a perf_event for it. Signed-off-by: Shannon Zhao <shannon.zhao@linaro.org> Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-07-03 09:27:25 +03:00
/**
* kvm_pmu_stop_counter - stop PMU counter
* @pmc: The PMU counter pointer
*
* If this counter has been configured to monitor some event, release it here.
*/
KVM: arm64: PMU: Make kvm_pmc the main data structure The PMU code has historically been torn between referencing a counter as a pair vcpu+index or as the PMC pointer. Given that it is pretty easy to go from one representation to the other, standardise on the latter which, IMHO, makes the code slightly more readable. YMMV. Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221113163832.3154370-17-maz@kernel.org
2022-11-13 19:38:32 +03:00
static void kvm_pmu_stop_counter(struct kvm_pmc *pmc)
arm64: KVM: PMU: Add perf event map and introduce perf event creating function When we use tools like perf on host, perf passes the event type and the id of this event type category to kernel, then kernel will map them to hardware event number and write this number to PMU PMEVTYPER<n>_EL0 register. When getting the event number in KVM, directly use raw event type to create a perf_event for it. Signed-off-by: Shannon Zhao <shannon.zhao@linaro.org> Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-07-03 09:27:25 +03:00
{
KVM: arm64: PMU: Make kvm_pmc the main data structure The PMU code has historically been torn between referencing a counter as a pair vcpu+index or as the PMC pointer. Given that it is pretty easy to go from one representation to the other, standardise on the latter which, IMHO, makes the code slightly more readable. YMMV. Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221113163832.3154370-17-maz@kernel.org
2022-11-13 19:38:32 +03:00
struct kvm_vcpu *vcpu = kvm_pmc_to_vcpu(pmc);
KVM: arm64: PMU: Only narrow counters that are not 64bit wide The current PMU emulation sometimes narrows counters to 32bit if the counter isn't the cycle counter. As this is going to change with PMUv3p5 where the counters are all 64bit, fix the couple of cases where this happens unconditionally. Signed-off-by: Marc Zyngier <maz@kernel.org> Reviewed-by: Reiji Watanabe <reijiw@google.com> Link: https://lore.kernel.org/r/20221113163832.3154370-7-maz@kernel.org
2022-11-13 19:38:22 +03:00
u64 reg, val;
arm64: KVM: PMU: Add perf event map and introduce perf event creating function When we use tools like perf on host, perf passes the event type and the id of this event type category to kernel, then kernel will map them to hardware event number and write this number to PMU PMEVTYPER<n>_EL0 register. When getting the event number in KVM, directly use raw event type to create a perf_event for it. Signed-off-by: Shannon Zhao <shannon.zhao@linaro.org> Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-07-03 09:27:25 +03:00
KVM: arm/arm64: Support chained PMU counters ARMv8 provides support for chained PMU counters, where an event type of 0x001E is set for odd-numbered counters, the event counter will increment by one for each overflow of the preceding even-numbered counter. Let's emulate this in KVM by creating a 64 bit perf counter when a user chains two emulated counters together. For chained events we only support generating an overflow interrupt on the high counter. We use the attributes of the low counter to determine the attributes of the perf event. Suggested-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Andrew Murray <andrew.murray@arm.com> Reviewed-by: Julien Thierry <julien.thierry@arm.com> Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2019-06-17 22:01:05 +03:00
if (!pmc->perf_event)
return;
KVM: arm64: PMU: Make kvm_pmc the main data structure The PMU code has historically been torn between referencing a counter as a pair vcpu+index or as the PMC pointer. Given that it is pretty easy to go from one representation to the other, standardise on the latter which, IMHO, makes the code slightly more readable. YMMV. Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221113163832.3154370-17-maz@kernel.org
2022-11-13 19:38:32 +03:00
val = kvm_pmu_get_pmc_value(pmc);
KVM: arm/arm64: Support chained PMU counters ARMv8 provides support for chained PMU counters, where an event type of 0x001E is set for odd-numbered counters, the event counter will increment by one for each overflow of the preceding even-numbered counter. Let's emulate this in KVM by creating a 64 bit perf counter when a user chains two emulated counters together. For chained events we only support generating an overflow interrupt on the high counter. We use the attributes of the low counter to determine the attributes of the perf event. Suggested-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Andrew Murray <andrew.murray@arm.com> Reviewed-by: Julien Thierry <julien.thierry@arm.com> Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2019-06-17 22:01:05 +03:00
KVM: arm64: PMU: Add counter_index_to_*reg() helpers In order to reduce the boilerplate code, add two helpers returning the counter register index (resp. the event register) in the vcpu register file from the counter index. Reviewed-by: Oliver Upton <oliver.upton@linux.dev> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221113163832.3154370-8-maz@kernel.org
2022-11-13 19:38:23 +03:00
reg = counter_index_to_reg(pmc->idx);
KVM: arm/arm64: Support chained PMU counters ARMv8 provides support for chained PMU counters, where an event type of 0x001E is set for odd-numbered counters, the event counter will increment by one for each overflow of the preceding even-numbered counter. Let's emulate this in KVM by creating a 64 bit perf counter when a user chains two emulated counters together. For chained events we only support generating an overflow interrupt on the high counter. We use the attributes of the low counter to determine the attributes of the perf event. Suggested-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Andrew Murray <andrew.murray@arm.com> Reviewed-by: Julien Thierry <julien.thierry@arm.com> Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2019-06-17 22:01:05 +03:00
KVM: arm64: pmu: Fix cycle counter truncation When a counter is disabled, its value is sampled before the event is being disabled, and the value written back in the shadow register. In that process, the value gets truncated to 32bit, which is adequate for any counter but the cycle counter (defined as a 64bit counter). This obviously results in a corrupted counter, and things like "perf record -e cycles" not working at all when run in a guest... A similar, but less critical bug exists in kvm_pmu_get_counter_value. Make the truncation conditional on the counter not being the cycle counter, which results in a minor code reorganisation. Fixes: 80f393a23be6 ("KVM: arm/arm64: Support chained PMU counters") Reviewed-by: Andrew Murray <andrew.murray@arm.com> Reported-by: Julien Thierry <julien.thierry.kdev@gmail.com> Signed-off-by: Marc Zyngier <maz@kernel.org>
2019-10-03 20:02:08 +03:00
__vcpu_sys_reg(vcpu, reg) = val;
KVM: arm/arm64: Support chained PMU counters ARMv8 provides support for chained PMU counters, where an event type of 0x001E is set for odd-numbered counters, the event counter will increment by one for each overflow of the preceding even-numbered counter. Let's emulate this in KVM by creating a 64 bit perf counter when a user chains two emulated counters together. For chained events we only support generating an overflow interrupt on the high counter. We use the attributes of the low counter to determine the attributes of the perf event. Suggested-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Andrew Murray <andrew.murray@arm.com> Reviewed-by: Julien Thierry <julien.thierry@arm.com> Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2019-06-17 22:01:05 +03:00
kvm_pmu_release_perf_event(pmc);
arm64: KVM: PMU: Add perf event map and introduce perf event creating function When we use tools like perf on host, perf passes the event type and the id of this event type category to kernel, then kernel will map them to hardware event number and write this number to PMU PMEVTYPER<n>_EL0 register. When getting the event number in KVM, directly use raw event type to create a perf_event for it. Signed-off-by: Shannon Zhao <shannon.zhao@linaro.org> Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-07-03 09:27:25 +03:00
}
KVM: arm/arm64: Introduce kvm_pmu_vcpu_init() to setup PMU counter index We use "pmc->idx" and the "chained" bitmap to determine if the pmc is chained, in kvm_pmu_pmc_is_chained(). But idx might be uninitialized (and random) when we doing this decision, through a KVM_ARM_VCPU_INIT ioctl -> kvm_pmu_vcpu_reset(). And the test_bit() against this random idx will potentially hit a KASAN BUG [1]. In general, idx is the static property of a PMU counter that is not expected to be modified across resets, as suggested by Julien. It looks more reasonable if we can setup the PMU counter idx for a vcpu in its creation time. Introduce a new function - kvm_pmu_vcpu_init() for this basic setup. Oh, and the KASAN BUG will get fixed this way. [1] https://www.spinics.net/lists/kvm-arm/msg36700.html Fixes: 80f393a23be6 ("KVM: arm/arm64: Support chained PMU counters") Suggested-by: Andrew Murray <andrew.murray@arm.com> Suggested-by: Julien Thierry <julien.thierry@arm.com> Acked-by: Julien Thierry <julien.thierry@arm.com> Signed-off-by: Zenghui Yu <yuzenghui@huawei.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2019-07-18 11:15:10 +03:00
/**
* kvm_pmu_vcpu_init - assign pmu counter idx for cpu
* @vcpu: The vcpu pointer
*
*/
void kvm_pmu_vcpu_init(struct kvm_vcpu *vcpu)
{
int i;
struct kvm_pmu *pmu = &vcpu->arch.pmu;
for (i = 0; i < ARMV8_PMU_MAX_COUNTERS; i++)
pmu->pmc[i].idx = i;
}
arm64: KVM: Reset PMU state when resetting vcpu When resetting vcpu, it needs to reset the PMU state to initial status. Signed-off-by: Shannon Zhao <shannon.zhao@linaro.org> Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> Reviewed-by: Andrew Jones <drjones@redhat.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-09-11 06:30:22 +03:00
/**
* kvm_pmu_vcpu_reset - reset pmu state for cpu
* @vcpu: The vcpu pointer
*
*/
void kvm_pmu_vcpu_reset(struct kvm_vcpu *vcpu)
{
KVM: arm64: pmu: Only handle supported event counters Let the code never use unsupported event counters. Change kvm_pmu_handle_pmcr() to only reset supported counters and kvm_pmu_vcpu_reset() to only stop supported counters. Other actions are filtered on the supported counters in kvm/sysregs.c Signed-off-by: Eric Auger <eric.auger@redhat.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20200124142535.29386-5-eric.auger@redhat.com
2020-01-24 17:25:35 +03:00
unsigned long mask = kvm_pmu_valid_counter_mask(vcpu);
int i;
arm64: KVM: Reset PMU state when resetting vcpu When resetting vcpu, it needs to reset the PMU state to initial status. Signed-off-by: Shannon Zhao <shannon.zhao@linaro.org> Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> Reviewed-by: Andrew Jones <drjones@redhat.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-09-11 06:30:22 +03:00
KVM: arm64: pmu: Only handle supported event counters Let the code never use unsupported event counters. Change kvm_pmu_handle_pmcr() to only reset supported counters and kvm_pmu_vcpu_reset() to only stop supported counters. Other actions are filtered on the supported counters in kvm/sysregs.c Signed-off-by: Eric Auger <eric.auger@redhat.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20200124142535.29386-5-eric.auger@redhat.com
2020-01-24 17:25:35 +03:00
for_each_set_bit(i, &mask, 32)
KVM: arm64: PMU: Make kvm_pmc the main data structure The PMU code has historically been torn between referencing a counter as a pair vcpu+index or as the PMC pointer. Given that it is pretty easy to go from one representation to the other, standardise on the latter which, IMHO, makes the code slightly more readable. YMMV. Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221113163832.3154370-17-maz@kernel.org
2022-11-13 19:38:32 +03:00
kvm_pmu_stop_counter(kvm_vcpu_idx_to_pmc(vcpu, i));
arm64: KVM: Reset PMU state when resetting vcpu When resetting vcpu, it needs to reset the PMU state to initial status. Signed-off-by: Shannon Zhao <shannon.zhao@linaro.org> Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> Reviewed-by: Andrew Jones <drjones@redhat.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-09-11 06:30:22 +03:00
}
arm64: KVM: Free perf event of PMU when destroying vcpu When KVM frees VCPU, it needs to free the perf_event of PMU. Signed-off-by: Shannon Zhao <shannon.zhao@linaro.org> Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> Reviewed-by: Andrew Jones <drjones@redhat.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-09-11 10:18:05 +03:00
/**
* kvm_pmu_vcpu_destroy - free perf event of PMU for cpu
* @vcpu: The vcpu pointer
*
*/
void kvm_pmu_vcpu_destroy(struct kvm_vcpu *vcpu)
{
int i;
KVM: arm/arm64: Extract duplicated code to own function Let's reduce code duplication by extracting common code to its own function. Signed-off-by: Andrew Murray <andrew.murray@arm.com> Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2019-06-17 22:01:02 +03:00
for (i = 0; i < ARMV8_PMU_MAX_COUNTERS; i++)
KVM: arm64: PMU: Make kvm_pmc the main data structure The PMU code has historically been torn between referencing a counter as a pair vcpu+index or as the PMC pointer. Given that it is pretty easy to go from one representation to the other, standardise on the latter which, IMHO, makes the code slightly more readable. YMMV. Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221113163832.3154370-17-maz@kernel.org
2022-11-13 19:38:32 +03:00
kvm_pmu_release_perf_event(kvm_vcpu_idx_to_pmc(vcpu, i));
KVM: arm64: pmu: Make overflow handler NMI safe kvm_vcpu_kick() is not NMI safe. When the overflow handler is called from NMI context, defer waking the vcpu to an irq_work queue. A vcpu can be freed while it's not running by kvm_destroy_vm(). Prevent running the irq_work for a non-existent vcpu by calling irq_work_sync() on the PMU destroy path. [Alexandru E.: Added irq_work_sync()] Signed-off-by: Julien Thierry <julien.thierry@arm.com> Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com> Tested-by: Sumit Garg <sumit.garg@linaro.org> (Developerbox) Cc: Julien Thierry <julien.thierry.kdev@gmail.com> Cc: Marc Zyngier <marc.zyngier@arm.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: James Morse <james.morse@arm.com> Cc: Suzuki K Pouloze <suzuki.poulose@arm.com> Cc: kvm@vger.kernel.org Cc: kvmarm@lists.cs.columbia.edu Link: https://lore.kernel.org/r/20200924110706.254996-6-alexandru.elisei@arm.com Signed-off-by: Will Deacon <will@kernel.org>
2020-09-24 14:07:04 +03:00
irq_work_sync(&vcpu->arch.pmu.overflow_work);
arm64: KVM: Free perf event of PMU when destroying vcpu When KVM frees VCPU, it needs to free the perf_event of PMU. Signed-off-by: Shannon Zhao <shannon.zhao@linaro.org> Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> Reviewed-by: Andrew Jones <drjones@redhat.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-09-11 10:18:05 +03:00
}
arm64: KVM: Add access handler for PMCNTENSET and PMCNTENCLR register Since the reset value of PMCNTENSET and PMCNTENCLR is UNKNOWN, use reset_unknown for its reset handler. Add a handler to emulate writing PMCNTENSET or PMCNTENCLR register. When writing to PMCNTENSET, call perf_event_enable to enable the perf event. When writing to PMCNTENCLR, call perf_event_disable to disable the perf event. Signed-off-by: Shannon Zhao <shannon.zhao@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-09-08 07:26:13 +03:00
u64 kvm_pmu_valid_counter_mask(struct kvm_vcpu *vcpu)
{
KVM: arm64: Rewrite system register accessors to read/write functions Currently we access the system registers array via the vcpu_sys_reg() macro. However, we are about to change the behavior to some times modify the register file directly, so let's change this to two primitives: * Accessor macros vcpu_write_sys_reg() and vcpu_read_sys_reg() * Direct array access macro __vcpu_sys_reg() The accessor macros should be used in places where the code needs to access the currently loaded VCPU's state as observed by the guest. For example, when trapping on cache related registers, a write to a system register should go directly to the VCPU version of the register. The direct array access macro can be used in places where the VCPU is known to never be running (for example userspace access) or for registers which are never context switched (for example all the PMU system registers). This rewrites all users of vcpu_sys_regs to one of the macros described above. No functional change. Acked-by: Marc Zyngier <marc.zyngier@arm.com> Reviewed-by: Andrew Jones <drjones@redhat.com> Signed-off-by: Christoffer Dall <cdall@cs.columbia.edu> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2016-03-16 17:38:53 +03:00
u64 val = __vcpu_sys_reg(vcpu, PMCR_EL0) >> ARMV8_PMU_PMCR_N_SHIFT;
arm64: KVM: Add access handler for PMCNTENSET and PMCNTENCLR register Since the reset value of PMCNTENSET and PMCNTENCLR is UNKNOWN, use reset_unknown for its reset handler. Add a handler to emulate writing PMCNTENSET or PMCNTENCLR register. When writing to PMCNTENSET, call perf_event_enable to enable the perf event. When writing to PMCNTENCLR, call perf_event_disable to disable the perf event. Signed-off-by: Shannon Zhao <shannon.zhao@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-09-08 07:26:13 +03:00
val &= ARMV8_PMU_PMCR_N_MASK;
if (val == 0)
return BIT(ARMV8_PMU_CYCLE_IDX);
else
return GENMASK(val - 1, 0) | BIT(ARMV8_PMU_CYCLE_IDX);
}
/**
KVM: arm/arm64: Rename kvm_pmu_{enable/disable}_counter functions The kvm_pmu_{enable/disable}_counter functions can enable/disable multiple counters at once as they operate on a bitmask. Let's make this clearer by renaming the function. Suggested-by: Suzuki K Poulose <suzuki.poulose@arm.com> Signed-off-by: Andrew Murray <andrew.murray@arm.com> Reviewed-by: Julien Thierry <julien.thierry@arm.com> Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2019-06-17 22:01:01 +03:00
* kvm_pmu_enable_counter_mask - enable selected PMU counters
arm64: KVM: Add access handler for PMCNTENSET and PMCNTENCLR register Since the reset value of PMCNTENSET and PMCNTENCLR is UNKNOWN, use reset_unknown for its reset handler. Add a handler to emulate writing PMCNTENSET or PMCNTENCLR register. When writing to PMCNTENSET, call perf_event_enable to enable the perf event. When writing to PMCNTENCLR, call perf_event_disable to disable the perf event. Signed-off-by: Shannon Zhao <shannon.zhao@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-09-08 07:26:13 +03:00
* @vcpu: The vcpu pointer
* @val: the value guest writes to PMCNTENSET register
*
* Call perf_event_enable to start counting the perf event
*/
KVM: arm/arm64: Rename kvm_pmu_{enable/disable}_counter functions The kvm_pmu_{enable/disable}_counter functions can enable/disable multiple counters at once as they operate on a bitmask. Let's make this clearer by renaming the function. Suggested-by: Suzuki K Poulose <suzuki.poulose@arm.com> Signed-off-by: Andrew Murray <andrew.murray@arm.com> Reviewed-by: Julien Thierry <julien.thierry@arm.com> Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2019-06-17 22:01:01 +03:00
void kvm_pmu_enable_counter_mask(struct kvm_vcpu *vcpu, u64 val)
arm64: KVM: Add access handler for PMCNTENSET and PMCNTENCLR register Since the reset value of PMCNTENSET and PMCNTENCLR is UNKNOWN, use reset_unknown for its reset handler. Add a handler to emulate writing PMCNTENSET or PMCNTENCLR register. When writing to PMCNTENSET, call perf_event_enable to enable the perf event. When writing to PMCNTENCLR, call perf_event_disable to disable the perf event. Signed-off-by: Shannon Zhao <shannon.zhao@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-09-08 07:26:13 +03:00
{
int i;
KVM/arm64: Don't emulate a PMU for 32-bit guests if feature not set kvm->arch.arm_pmu is set when userspace attempts to set the first PMU attribute. As certain attributes are mandatory, arm_pmu ends up always being set to a valid arm_pmu, otherwise KVM will refuse to run the VCPU. However, this only happens if the VCPU has the PMU feature. If the VCPU doesn't have the feature bit set, kvm->arch.arm_pmu will be left uninitialized and equal to NULL. KVM doesn't do ID register emulation for 32-bit guests and accesses to the PMU registers aren't gated by the pmu_visibility() function. This is done to prevent injecting unexpected undefined exceptions in guests which have detected the presence of a hardware PMU. But even though the VCPU feature is missing, KVM still attempts to emulate certain aspects of the PMU when PMU registers are accessed. This leads to a NULL pointer dereference like this one, which happens on an odroid-c4 board when running the kvm-unit-tests pmu-cycle-counter test with kvmtool and without the PMU feature being set: [ 454.402699] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000150 [ 454.405865] Mem abort info: [ 454.408596] ESR = 0x96000004 [ 454.411638] EC = 0x25: DABT (current EL), IL = 32 bits [ 454.416901] SET = 0, FnV = 0 [ 454.419909] EA = 0, S1PTW = 0 [ 454.423010] FSC = 0x04: level 0 translation fault [ 454.427841] Data abort info: [ 454.430687] ISV = 0, ISS = 0x00000004 [ 454.434484] CM = 0, WnR = 0 [ 454.437404] user pgtable: 4k pages, 48-bit VAs, pgdp=000000000c924000 [ 454.443800] [0000000000000150] pgd=0000000000000000, p4d=0000000000000000 [ 454.450528] Internal error: Oops: 96000004 [#1] PREEMPT SMP [ 454.456036] Modules linked in: [ 454.459053] CPU: 1 PID: 267 Comm: kvm-vcpu-0 Not tainted 5.18.0-rc4 #113 [ 454.465697] Hardware name: Hardkernel ODROID-C4 (DT) [ 454.470612] pstate: 60400009 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) [ 454.477512] pc : kvm_pmu_event_mask.isra.0+0x14/0x74 [ 454.482427] lr : kvm_pmu_set_counter_event_type+0x2c/0x80 [ 454.487775] sp : ffff80000a9839c0 [ 454.491050] x29: ffff80000a9839c0 x28: ffff000000a83a00 x27: 0000000000000000 [ 454.498127] x26: 0000000000000000 x25: 0000000000000000 x24: ffff00000a510000 [ 454.505198] x23: ffff000000a83a00 x22: ffff000003b01000 x21: 0000000000000000 [ 454.512271] x20: 000000000000001f x19: 00000000000003ff x18: 0000000000000000 [ 454.519343] x17: 000000008003fe98 x16: 0000000000000000 x15: 0000000000000000 [ 454.526416] x14: 0000000000000000 x13: 0000000000000000 x12: 0000000000000000 [ 454.533489] x11: 000000008003fdbc x10: 0000000000009d20 x9 : 000000000000001b [ 454.540561] x8 : 0000000000000000 x7 : 0000000000000d00 x6 : 0000000000009d00 [ 454.547633] x5 : 0000000000000037 x4 : 0000000000009d00 x3 : 0d09000000000000 [ 454.554705] x2 : 000000000000001f x1 : 0000000000000000 x0 : 0000000000000000 [ 454.561779] Call trace: [ 454.564191] kvm_pmu_event_mask.isra.0+0x14/0x74 [ 454.568764] kvm_pmu_set_counter_event_type+0x2c/0x80 [ 454.573766] access_pmu_evtyper+0x128/0x170 [ 454.577905] perform_access+0x34/0x80 [ 454.581527] kvm_handle_cp_32+0x13c/0x160 [ 454.585495] kvm_handle_cp15_32+0x1c/0x30 [ 454.589462] handle_exit+0x70/0x180 [ 454.592912] kvm_arch_vcpu_ioctl_run+0x1c4/0x5e0 [ 454.597485] kvm_vcpu_ioctl+0x23c/0x940 [ 454.601280] __arm64_sys_ioctl+0xa8/0xf0 [ 454.605160] invoke_syscall+0x48/0x114 [ 454.608869] el0_svc_common.constprop.0+0xd4/0xfc [ 454.613527] do_el0_svc+0x28/0x90 [ 454.616803] el0_svc+0x34/0xb0 [ 454.619822] el0t_64_sync_handler+0xa4/0x130 [ 454.624049] el0t_64_sync+0x18c/0x190 [ 454.627675] Code: a9be7bfd 910003fd f9000bf3 52807ff3 (b9415001) [ 454.633714] ---[ end trace 0000000000000000 ]--- In this particular case, Linux hasn't detected the presence of a hardware PMU because the PMU node is missing from the DTB, so userspace would have been unable to set the VCPU PMU feature even if it attempted it. What happens is that the 32-bit guest reads ID_DFR0, which advertises the presence of the PMU, and when it tries to program a counter, it triggers the NULL pointer dereference because kvm->arch.arm_pmu is NULL. kvm-arch.arm_pmu was introduced by commit 46b187821472 ("KVM: arm64: Keep a per-VM pointer to the default PMU"). Until that commit, this error would be triggered instead: [ 73.388140] ------------[ cut here ]------------ [ 73.388189] Unknown PMU version 0 [ 73.390420] WARNING: CPU: 1 PID: 264 at arch/arm64/kvm/pmu-emul.c:36 kvm_pmu_event_mask.isra.0+0x6c/0x74 [ 73.399821] Modules linked in: [ 73.402835] CPU: 1 PID: 264 Comm: kvm-vcpu-0 Not tainted 5.17.0 #114 [ 73.409132] Hardware name: Hardkernel ODROID-C4 (DT) [ 73.414048] pstate: 60400009 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) [ 73.420948] pc : kvm_pmu_event_mask.isra.0+0x6c/0x74 [ 73.425863] lr : kvm_pmu_event_mask.isra.0+0x6c/0x74 [ 73.430779] sp : ffff80000a8db9b0 [ 73.434055] x29: ffff80000a8db9b0 x28: ffff000000dbaac0 x27: 0000000000000000 [ 73.441131] x26: ffff000000dbaac0 x25: 00000000c600000d x24: 0000000000180720 [ 73.448203] x23: ffff800009ffbe10 x22: ffff00000b612000 x21: 0000000000000000 [ 73.455276] x20: 000000000000001f x19: 0000000000000000 x18: ffffffffffffffff [ 73.462348] x17: 000000008003fe98 x16: 0000000000000000 x15: 0720072007200720 [ 73.469420] x14: 0720072007200720 x13: ffff800009d32488 x12: 00000000000004e6 [ 73.476493] x11: 00000000000001a2 x10: ffff800009d32488 x9 : ffff800009d32488 [ 73.483565] x8 : 00000000ffffefff x7 : ffff800009d8a488 x6 : ffff800009d8a488 [ 73.490638] x5 : ffff0000f461a9d8 x4 : 0000000000000000 x3 : 0000000000000001 [ 73.497710] x2 : 0000000000000000 x1 : 0000000000000000 x0 : ffff000000dbaac0 [ 73.504784] Call trace: [ 73.507195] kvm_pmu_event_mask.isra.0+0x6c/0x74 [ 73.511768] kvm_pmu_set_counter_event_type+0x2c/0x80 [ 73.516770] access_pmu_evtyper+0x128/0x16c [ 73.520910] perform_access+0x34/0x80 [ 73.524532] kvm_handle_cp_32+0x13c/0x160 [ 73.528500] kvm_handle_cp15_32+0x1c/0x30 [ 73.532467] handle_exit+0x70/0x180 [ 73.535917] kvm_arch_vcpu_ioctl_run+0x20c/0x6e0 [ 73.540489] kvm_vcpu_ioctl+0x2b8/0x9e0 [ 73.544283] __arm64_sys_ioctl+0xa8/0xf0 [ 73.548165] invoke_syscall+0x48/0x114 [ 73.551874] el0_svc_common.constprop.0+0xd4/0xfc [ 73.556531] do_el0_svc+0x28/0x90 [ 73.559808] el0_svc+0x28/0x80 [ 73.562826] el0t_64_sync_handler+0xa4/0x130 [ 73.567054] el0t_64_sync+0x1a0/0x1a4 [ 73.570676] ---[ end trace 0000000000000000 ]--- [ 73.575382] kvm: pmu event creation failed -2 The root cause remains the same: kvm->arch.pmuver was never set to something sensible because the VCPU feature itself was never set. The odroid-c4 is somewhat of a special case, because Linux doesn't probe the PMU. But the above errors can easily be reproduced on any hardware, with or without a PMU driver, as long as userspace doesn't set the PMU feature. Work around the fact that KVM advertises a PMU even when the VCPU feature is not set by gating all PMU emulation on the feature. The guest can still access the registers without KVM injecting an undefined exception. Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20220425145530.723858-1-alexandru.elisei@arm.com
2022-04-25 17:55:30 +03:00
if (!kvm_vcpu_has_pmu(vcpu))
return;
KVM: arm64: Rewrite system register accessors to read/write functions Currently we access the system registers array via the vcpu_sys_reg() macro. However, we are about to change the behavior to some times modify the register file directly, so let's change this to two primitives: * Accessor macros vcpu_write_sys_reg() and vcpu_read_sys_reg() * Direct array access macro __vcpu_sys_reg() The accessor macros should be used in places where the code needs to access the currently loaded VCPU's state as observed by the guest. For example, when trapping on cache related registers, a write to a system register should go directly to the VCPU version of the register. The direct array access macro can be used in places where the VCPU is known to never be running (for example userspace access) or for registers which are never context switched (for example all the PMU system registers). This rewrites all users of vcpu_sys_regs to one of the macros described above. No functional change. Acked-by: Marc Zyngier <marc.zyngier@arm.com> Reviewed-by: Andrew Jones <drjones@redhat.com> Signed-off-by: Christoffer Dall <cdall@cs.columbia.edu> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2016-03-16 17:38:53 +03:00
if (!(__vcpu_sys_reg(vcpu, PMCR_EL0) & ARMV8_PMU_PMCR_E) || !val)
arm64: KVM: Add access handler for PMCNTENSET and PMCNTENCLR register Since the reset value of PMCNTENSET and PMCNTENCLR is UNKNOWN, use reset_unknown for its reset handler. Add a handler to emulate writing PMCNTENSET or PMCNTENCLR register. When writing to PMCNTENSET, call perf_event_enable to enable the perf event. When writing to PMCNTENCLR, call perf_event_disable to disable the perf event. Signed-off-by: Shannon Zhao <shannon.zhao@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-09-08 07:26:13 +03:00
return;
for (i = 0; i < ARMV8_PMU_MAX_COUNTERS; i++) {
KVM: arm64: PMU: Make kvm_pmc the main data structure The PMU code has historically been torn between referencing a counter as a pair vcpu+index or as the PMC pointer. Given that it is pretty easy to go from one representation to the other, standardise on the latter which, IMHO, makes the code slightly more readable. YMMV. Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221113163832.3154370-17-maz@kernel.org
2022-11-13 19:38:32 +03:00
struct kvm_pmc *pmc;
arm64: KVM: Add access handler for PMCNTENSET and PMCNTENCLR register Since the reset value of PMCNTENSET and PMCNTENCLR is UNKNOWN, use reset_unknown for its reset handler. Add a handler to emulate writing PMCNTENSET or PMCNTENCLR register. When writing to PMCNTENSET, call perf_event_enable to enable the perf event. When writing to PMCNTENCLR, call perf_event_disable to disable the perf event. Signed-off-by: Shannon Zhao <shannon.zhao@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-09-08 07:26:13 +03:00
if (!(val & BIT(i)))
continue;
KVM: arm64: PMU: Make kvm_pmc the main data structure The PMU code has historically been torn between referencing a counter as a pair vcpu+index or as the PMC pointer. Given that it is pretty easy to go from one representation to the other, standardise on the latter which, IMHO, makes the code slightly more readable. YMMV. Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221113163832.3154370-17-maz@kernel.org
2022-11-13 19:38:32 +03:00
pmc = kvm_vcpu_idx_to_pmc(vcpu, i);
KVM: arm/arm64: Support chained PMU counters ARMv8 provides support for chained PMU counters, where an event type of 0x001E is set for odd-numbered counters, the event counter will increment by one for each overflow of the preceding even-numbered counter. Let's emulate this in KVM by creating a 64 bit perf counter when a user chains two emulated counters together. For chained events we only support generating an overflow interrupt on the high counter. We use the attributes of the low counter to determine the attributes of the perf event. Suggested-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Andrew Murray <andrew.murray@arm.com> Reviewed-by: Julien Thierry <julien.thierry@arm.com> Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2019-06-17 22:01:05 +03:00
KVM: arm64: PMU: Align chained counter implementation with architecture pseudocode Ricardo recently pointed out that the PMU chained counter emulation in KVM wasn't quite behaving like the one on actual hardware, in the sense that a chained counter would expose an overflow on both halves of a chained counter, while KVM would only expose the overflow on the top half. The difference is subtle, but significant. What does the architecture say (DDI0087 H.a): - Up to PMUv3p4, all counters but the cycle counter are 32bit - A 32bit counter that overflows generates a CHAIN event on the adjacent counter after exposing its own overflow status - The CHAIN event is accounted if the counter is correctly configured (CHAIN event selected and counter enabled) This all means that our current implementation (which uses 64bit perf events) prevents us from emulating this overflow on the lower half. How to fix this? By implementing the above, to the letter. This largely results in code deletion, removing the notions of "counter pair", "chained counters", and "canonical counter". The code is further restructured to make the CHAIN handling similar to SWINC, as the two are now extremely similar in behaviour. Reported-by: Ricardo Koller <ricarkol@google.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Reviewed-by: Reiji Watanabe <reijiw@google.com> Link: https://lore.kernel.org/r/20221113163832.3154370-3-maz@kernel.org
2022-11-13 19:38:18 +03:00
if (!pmc->perf_event) {
KVM: arm64: PMU: Make kvm_pmc the main data structure The PMU code has historically been torn between referencing a counter as a pair vcpu+index or as the PMC pointer. Given that it is pretty easy to go from one representation to the other, standardise on the latter which, IMHO, makes the code slightly more readable. YMMV. Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221113163832.3154370-17-maz@kernel.org
2022-11-13 19:38:32 +03:00
kvm_pmu_create_perf_event(pmc);
KVM: arm64: PMU: Align chained counter implementation with architecture pseudocode Ricardo recently pointed out that the PMU chained counter emulation in KVM wasn't quite behaving like the one on actual hardware, in the sense that a chained counter would expose an overflow on both halves of a chained counter, while KVM would only expose the overflow on the top half. The difference is subtle, but significant. What does the architecture say (DDI0087 H.a): - Up to PMUv3p4, all counters but the cycle counter are 32bit - A 32bit counter that overflows generates a CHAIN event on the adjacent counter after exposing its own overflow status - The CHAIN event is accounted if the counter is correctly configured (CHAIN event selected and counter enabled) This all means that our current implementation (which uses 64bit perf events) prevents us from emulating this overflow on the lower half. How to fix this? By implementing the above, to the letter. This largely results in code deletion, removing the notions of "counter pair", "chained counters", and "canonical counter". The code is further restructured to make the CHAIN handling similar to SWINC, as the two are now extremely similar in behaviour. Reported-by: Ricardo Koller <ricarkol@google.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Reviewed-by: Reiji Watanabe <reijiw@google.com> Link: https://lore.kernel.org/r/20221113163832.3154370-3-maz@kernel.org
2022-11-13 19:38:18 +03:00
} else {
arm64: KVM: Add access handler for PMCNTENSET and PMCNTENCLR register Since the reset value of PMCNTENSET and PMCNTENCLR is UNKNOWN, use reset_unknown for its reset handler. Add a handler to emulate writing PMCNTENSET or PMCNTENCLR register. When writing to PMCNTENSET, call perf_event_enable to enable the perf event. When writing to PMCNTENCLR, call perf_event_disable to disable the perf event. Signed-off-by: Shannon Zhao <shannon.zhao@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-09-08 07:26:13 +03:00
perf_event_enable(pmc->perf_event);
if (pmc->perf_event->state != PERF_EVENT_STATE_ACTIVE)
kvm_debug("fail to enable perf event\n");
}
}
}
/**
KVM: arm/arm64: Rename kvm_pmu_{enable/disable}_counter functions The kvm_pmu_{enable/disable}_counter functions can enable/disable multiple counters at once as they operate on a bitmask. Let's make this clearer by renaming the function. Suggested-by: Suzuki K Poulose <suzuki.poulose@arm.com> Signed-off-by: Andrew Murray <andrew.murray@arm.com> Reviewed-by: Julien Thierry <julien.thierry@arm.com> Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2019-06-17 22:01:01 +03:00
* kvm_pmu_disable_counter_mask - disable selected PMU counters
arm64: KVM: Add access handler for PMCNTENSET and PMCNTENCLR register Since the reset value of PMCNTENSET and PMCNTENCLR is UNKNOWN, use reset_unknown for its reset handler. Add a handler to emulate writing PMCNTENSET or PMCNTENCLR register. When writing to PMCNTENSET, call perf_event_enable to enable the perf event. When writing to PMCNTENCLR, call perf_event_disable to disable the perf event. Signed-off-by: Shannon Zhao <shannon.zhao@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-09-08 07:26:13 +03:00
* @vcpu: The vcpu pointer
* @val: the value guest writes to PMCNTENCLR register
*
* Call perf_event_disable to stop counting the perf event
*/
KVM: arm/arm64: Rename kvm_pmu_{enable/disable}_counter functions The kvm_pmu_{enable/disable}_counter functions can enable/disable multiple counters at once as they operate on a bitmask. Let's make this clearer by renaming the function. Suggested-by: Suzuki K Poulose <suzuki.poulose@arm.com> Signed-off-by: Andrew Murray <andrew.murray@arm.com> Reviewed-by: Julien Thierry <julien.thierry@arm.com> Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2019-06-17 22:01:01 +03:00
void kvm_pmu_disable_counter_mask(struct kvm_vcpu *vcpu, u64 val)
arm64: KVM: Add access handler for PMCNTENSET and PMCNTENCLR register Since the reset value of PMCNTENSET and PMCNTENCLR is UNKNOWN, use reset_unknown for its reset handler. Add a handler to emulate writing PMCNTENSET or PMCNTENCLR register. When writing to PMCNTENSET, call perf_event_enable to enable the perf event. When writing to PMCNTENCLR, call perf_event_disable to disable the perf event. Signed-off-by: Shannon Zhao <shannon.zhao@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-09-08 07:26:13 +03:00
{
int i;
KVM/arm64: Don't emulate a PMU for 32-bit guests if feature not set kvm->arch.arm_pmu is set when userspace attempts to set the first PMU attribute. As certain attributes are mandatory, arm_pmu ends up always being set to a valid arm_pmu, otherwise KVM will refuse to run the VCPU. However, this only happens if the VCPU has the PMU feature. If the VCPU doesn't have the feature bit set, kvm->arch.arm_pmu will be left uninitialized and equal to NULL. KVM doesn't do ID register emulation for 32-bit guests and accesses to the PMU registers aren't gated by the pmu_visibility() function. This is done to prevent injecting unexpected undefined exceptions in guests which have detected the presence of a hardware PMU. But even though the VCPU feature is missing, KVM still attempts to emulate certain aspects of the PMU when PMU registers are accessed. This leads to a NULL pointer dereference like this one, which happens on an odroid-c4 board when running the kvm-unit-tests pmu-cycle-counter test with kvmtool and without the PMU feature being set: [ 454.402699] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000150 [ 454.405865] Mem abort info: [ 454.408596] ESR = 0x96000004 [ 454.411638] EC = 0x25: DABT (current EL), IL = 32 bits [ 454.416901] SET = 0, FnV = 0 [ 454.419909] EA = 0, S1PTW = 0 [ 454.423010] FSC = 0x04: level 0 translation fault [ 454.427841] Data abort info: [ 454.430687] ISV = 0, ISS = 0x00000004 [ 454.434484] CM = 0, WnR = 0 [ 454.437404] user pgtable: 4k pages, 48-bit VAs, pgdp=000000000c924000 [ 454.443800] [0000000000000150] pgd=0000000000000000, p4d=0000000000000000 [ 454.450528] Internal error: Oops: 96000004 [#1] PREEMPT SMP [ 454.456036] Modules linked in: [ 454.459053] CPU: 1 PID: 267 Comm: kvm-vcpu-0 Not tainted 5.18.0-rc4 #113 [ 454.465697] Hardware name: Hardkernel ODROID-C4 (DT) [ 454.470612] pstate: 60400009 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) [ 454.477512] pc : kvm_pmu_event_mask.isra.0+0x14/0x74 [ 454.482427] lr : kvm_pmu_set_counter_event_type+0x2c/0x80 [ 454.487775] sp : ffff80000a9839c0 [ 454.491050] x29: ffff80000a9839c0 x28: ffff000000a83a00 x27: 0000000000000000 [ 454.498127] x26: 0000000000000000 x25: 0000000000000000 x24: ffff00000a510000 [ 454.505198] x23: ffff000000a83a00 x22: ffff000003b01000 x21: 0000000000000000 [ 454.512271] x20: 000000000000001f x19: 00000000000003ff x18: 0000000000000000 [ 454.519343] x17: 000000008003fe98 x16: 0000000000000000 x15: 0000000000000000 [ 454.526416] x14: 0000000000000000 x13: 0000000000000000 x12: 0000000000000000 [ 454.533489] x11: 000000008003fdbc x10: 0000000000009d20 x9 : 000000000000001b [ 454.540561] x8 : 0000000000000000 x7 : 0000000000000d00 x6 : 0000000000009d00 [ 454.547633] x5 : 0000000000000037 x4 : 0000000000009d00 x3 : 0d09000000000000 [ 454.554705] x2 : 000000000000001f x1 : 0000000000000000 x0 : 0000000000000000 [ 454.561779] Call trace: [ 454.564191] kvm_pmu_event_mask.isra.0+0x14/0x74 [ 454.568764] kvm_pmu_set_counter_event_type+0x2c/0x80 [ 454.573766] access_pmu_evtyper+0x128/0x170 [ 454.577905] perform_access+0x34/0x80 [ 454.581527] kvm_handle_cp_32+0x13c/0x160 [ 454.585495] kvm_handle_cp15_32+0x1c/0x30 [ 454.589462] handle_exit+0x70/0x180 [ 454.592912] kvm_arch_vcpu_ioctl_run+0x1c4/0x5e0 [ 454.597485] kvm_vcpu_ioctl+0x23c/0x940 [ 454.601280] __arm64_sys_ioctl+0xa8/0xf0 [ 454.605160] invoke_syscall+0x48/0x114 [ 454.608869] el0_svc_common.constprop.0+0xd4/0xfc [ 454.613527] do_el0_svc+0x28/0x90 [ 454.616803] el0_svc+0x34/0xb0 [ 454.619822] el0t_64_sync_handler+0xa4/0x130 [ 454.624049] el0t_64_sync+0x18c/0x190 [ 454.627675] Code: a9be7bfd 910003fd f9000bf3 52807ff3 (b9415001) [ 454.633714] ---[ end trace 0000000000000000 ]--- In this particular case, Linux hasn't detected the presence of a hardware PMU because the PMU node is missing from the DTB, so userspace would have been unable to set the VCPU PMU feature even if it attempted it. What happens is that the 32-bit guest reads ID_DFR0, which advertises the presence of the PMU, and when it tries to program a counter, it triggers the NULL pointer dereference because kvm->arch.arm_pmu is NULL. kvm-arch.arm_pmu was introduced by commit 46b187821472 ("KVM: arm64: Keep a per-VM pointer to the default PMU"). Until that commit, this error would be triggered instead: [ 73.388140] ------------[ cut here ]------------ [ 73.388189] Unknown PMU version 0 [ 73.390420] WARNING: CPU: 1 PID: 264 at arch/arm64/kvm/pmu-emul.c:36 kvm_pmu_event_mask.isra.0+0x6c/0x74 [ 73.399821] Modules linked in: [ 73.402835] CPU: 1 PID: 264 Comm: kvm-vcpu-0 Not tainted 5.17.0 #114 [ 73.409132] Hardware name: Hardkernel ODROID-C4 (DT) [ 73.414048] pstate: 60400009 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) [ 73.420948] pc : kvm_pmu_event_mask.isra.0+0x6c/0x74 [ 73.425863] lr : kvm_pmu_event_mask.isra.0+0x6c/0x74 [ 73.430779] sp : ffff80000a8db9b0 [ 73.434055] x29: ffff80000a8db9b0 x28: ffff000000dbaac0 x27: 0000000000000000 [ 73.441131] x26: ffff000000dbaac0 x25: 00000000c600000d x24: 0000000000180720 [ 73.448203] x23: ffff800009ffbe10 x22: ffff00000b612000 x21: 0000000000000000 [ 73.455276] x20: 000000000000001f x19: 0000000000000000 x18: ffffffffffffffff [ 73.462348] x17: 000000008003fe98 x16: 0000000000000000 x15: 0720072007200720 [ 73.469420] x14: 0720072007200720 x13: ffff800009d32488 x12: 00000000000004e6 [ 73.476493] x11: 00000000000001a2 x10: ffff800009d32488 x9 : ffff800009d32488 [ 73.483565] x8 : 00000000ffffefff x7 : ffff800009d8a488 x6 : ffff800009d8a488 [ 73.490638] x5 : ffff0000f461a9d8 x4 : 0000000000000000 x3 : 0000000000000001 [ 73.497710] x2 : 0000000000000000 x1 : 0000000000000000 x0 : ffff000000dbaac0 [ 73.504784] Call trace: [ 73.507195] kvm_pmu_event_mask.isra.0+0x6c/0x74 [ 73.511768] kvm_pmu_set_counter_event_type+0x2c/0x80 [ 73.516770] access_pmu_evtyper+0x128/0x16c [ 73.520910] perform_access+0x34/0x80 [ 73.524532] kvm_handle_cp_32+0x13c/0x160 [ 73.528500] kvm_handle_cp15_32+0x1c/0x30 [ 73.532467] handle_exit+0x70/0x180 [ 73.535917] kvm_arch_vcpu_ioctl_run+0x20c/0x6e0 [ 73.540489] kvm_vcpu_ioctl+0x2b8/0x9e0 [ 73.544283] __arm64_sys_ioctl+0xa8/0xf0 [ 73.548165] invoke_syscall+0x48/0x114 [ 73.551874] el0_svc_common.constprop.0+0xd4/0xfc [ 73.556531] do_el0_svc+0x28/0x90 [ 73.559808] el0_svc+0x28/0x80 [ 73.562826] el0t_64_sync_handler+0xa4/0x130 [ 73.567054] el0t_64_sync+0x1a0/0x1a4 [ 73.570676] ---[ end trace 0000000000000000 ]--- [ 73.575382] kvm: pmu event creation failed -2 The root cause remains the same: kvm->arch.pmuver was never set to something sensible because the VCPU feature itself was never set. The odroid-c4 is somewhat of a special case, because Linux doesn't probe the PMU. But the above errors can easily be reproduced on any hardware, with or without a PMU driver, as long as userspace doesn't set the PMU feature. Work around the fact that KVM advertises a PMU even when the VCPU feature is not set by gating all PMU emulation on the feature. The guest can still access the registers without KVM injecting an undefined exception. Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20220425145530.723858-1-alexandru.elisei@arm.com
2022-04-25 17:55:30 +03:00
if (!kvm_vcpu_has_pmu(vcpu) || !val)
arm64: KVM: Add access handler for PMCNTENSET and PMCNTENCLR register Since the reset value of PMCNTENSET and PMCNTENCLR is UNKNOWN, use reset_unknown for its reset handler. Add a handler to emulate writing PMCNTENSET or PMCNTENCLR register. When writing to PMCNTENSET, call perf_event_enable to enable the perf event. When writing to PMCNTENCLR, call perf_event_disable to disable the perf event. Signed-off-by: Shannon Zhao <shannon.zhao@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-09-08 07:26:13 +03:00
return;
for (i = 0; i < ARMV8_PMU_MAX_COUNTERS; i++) {
KVM: arm64: PMU: Make kvm_pmc the main data structure The PMU code has historically been torn between referencing a counter as a pair vcpu+index or as the PMC pointer. Given that it is pretty easy to go from one representation to the other, standardise on the latter which, IMHO, makes the code slightly more readable. YMMV. Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221113163832.3154370-17-maz@kernel.org
2022-11-13 19:38:32 +03:00
struct kvm_pmc *pmc;
arm64: KVM: Add access handler for PMCNTENSET and PMCNTENCLR register Since the reset value of PMCNTENSET and PMCNTENCLR is UNKNOWN, use reset_unknown for its reset handler. Add a handler to emulate writing PMCNTENSET or PMCNTENCLR register. When writing to PMCNTENSET, call perf_event_enable to enable the perf event. When writing to PMCNTENCLR, call perf_event_disable to disable the perf event. Signed-off-by: Shannon Zhao <shannon.zhao@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-09-08 07:26:13 +03:00
if (!(val & BIT(i)))
continue;
KVM: arm64: PMU: Make kvm_pmc the main data structure The PMU code has historically been torn between referencing a counter as a pair vcpu+index or as the PMC pointer. Given that it is pretty easy to go from one representation to the other, standardise on the latter which, IMHO, makes the code slightly more readable. YMMV. Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221113163832.3154370-17-maz@kernel.org
2022-11-13 19:38:32 +03:00
pmc = kvm_vcpu_idx_to_pmc(vcpu, i);
KVM: arm/arm64: Support chained PMU counters ARMv8 provides support for chained PMU counters, where an event type of 0x001E is set for odd-numbered counters, the event counter will increment by one for each overflow of the preceding even-numbered counter. Let's emulate this in KVM by creating a 64 bit perf counter when a user chains two emulated counters together. For chained events we only support generating an overflow interrupt on the high counter. We use the attributes of the low counter to determine the attributes of the perf event. Suggested-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Andrew Murray <andrew.murray@arm.com> Reviewed-by: Julien Thierry <julien.thierry@arm.com> Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2019-06-17 22:01:05 +03:00
arm64: KVM: Add access handler for PMCNTENSET and PMCNTENCLR register Since the reset value of PMCNTENSET and PMCNTENCLR is UNKNOWN, use reset_unknown for its reset handler. Add a handler to emulate writing PMCNTENSET or PMCNTENCLR register. When writing to PMCNTENSET, call perf_event_enable to enable the perf event. When writing to PMCNTENCLR, call perf_event_disable to disable the perf event. Signed-off-by: Shannon Zhao <shannon.zhao@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-09-08 07:26:13 +03:00
if (pmc->perf_event)
perf_event_disable(pmc->perf_event);
}
}
arm64: KVM: PMU: Add perf event map and introduce perf event creating function When we use tools like perf on host, perf passes the event type and the id of this event type category to kernel, then kernel will map them to hardware event number and write this number to PMU PMEVTYPER<n>_EL0 register. When getting the event number in KVM, directly use raw event type to create a perf_event for it. Signed-off-by: Shannon Zhao <shannon.zhao@linaro.org> Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-07-03 09:27:25 +03:00
arm64: KVM: Add access handler for PMOVSSET and PMOVSCLR register Since the reset value of PMOVSSET and PMOVSCLR is UNKNOWN, use reset_unknown for its reset handler. Add a handler to emulate writing PMOVSSET or PMOVSCLR register. When writing non-zero value to PMOVSSET, the counter and its interrupt is enabled, kick this vcpu to sync PMU interrupt. Signed-off-by: Shannon Zhao <shannon.zhao@linaro.org> Reviewed-by: Andrew Jones <drjones@redhat.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-09-08 10:03:26 +03:00
static u64 kvm_pmu_overflow_status(struct kvm_vcpu *vcpu)
{
u64 reg = 0;
KVM: arm64: Rewrite system register accessors to read/write functions Currently we access the system registers array via the vcpu_sys_reg() macro. However, we are about to change the behavior to some times modify the register file directly, so let's change this to two primitives: * Accessor macros vcpu_write_sys_reg() and vcpu_read_sys_reg() * Direct array access macro __vcpu_sys_reg() The accessor macros should be used in places where the code needs to access the currently loaded VCPU's state as observed by the guest. For example, when trapping on cache related registers, a write to a system register should go directly to the VCPU version of the register. The direct array access macro can be used in places where the VCPU is known to never be running (for example userspace access) or for registers which are never context switched (for example all the PMU system registers). This rewrites all users of vcpu_sys_regs to one of the macros described above. No functional change. Acked-by: Marc Zyngier <marc.zyngier@arm.com> Reviewed-by: Andrew Jones <drjones@redhat.com> Signed-off-by: Christoffer Dall <cdall@cs.columbia.edu> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2016-03-16 17:38:53 +03:00
if ((__vcpu_sys_reg(vcpu, PMCR_EL0) & ARMV8_PMU_PMCR_E)) {
reg = __vcpu_sys_reg(vcpu, PMOVSSET_EL0);
reg &= __vcpu_sys_reg(vcpu, PMCNTENSET_EL0);
reg &= __vcpu_sys_reg(vcpu, PMINTENSET_EL1);
arm64: KVM: Add braces to multi-line if statement in virtual PMU code The kernel is written in C, not python, so we need braces around multi-line if statements. GCC 6 actually warns about this, thanks to the fantastic new "-Wmisleading-indentation" flag: | virt/kvm/arm/pmu.c: In function ‘kvm_pmu_overflow_status’: | virt/kvm/arm/pmu.c:198:3: warning: statement is indented as if it were guarded by... [-Wmisleading-indentation] | reg &= vcpu_sys_reg(vcpu, PMCNTENSET_EL0); | ^~~ | arch/arm64/kvm/../../../virt/kvm/arm/pmu.c:196:2: note: ...this ‘if’ clause, but it is not | if ((vcpu_sys_reg(vcpu, PMCR_EL0) & ARMV8_PMU_PMCR_E)) | ^~ As it turns out, this particular case is harmless (we just do some &= operations with 0), but worth fixing nonetheless. Signed-off-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
2016-04-01 14:12:22 +03:00
}
arm64: KVM: Add access handler for PMOVSSET and PMOVSCLR register Since the reset value of PMOVSSET and PMOVSCLR is UNKNOWN, use reset_unknown for its reset handler. Add a handler to emulate writing PMOVSSET or PMOVSCLR register. When writing non-zero value to PMOVSSET, the counter and its interrupt is enabled, kick this vcpu to sync PMU interrupt. Signed-off-by: Shannon Zhao <shannon.zhao@linaro.org> Reviewed-by: Andrew Jones <drjones@redhat.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-09-08 10:03:26 +03:00
return reg;
}
KVM: arm/arm64: PMU: Fix overflow interrupt injection kvm_pmu_overflow_set() is called from perf's interrupt handler, making the call of kvm_vgic_inject_irq() from it introduced with "KVM: arm/arm64: PMU: remove request-less vcpu kick" a really bad idea, as it's quite easy to try and retake a lock that the interrupted context is already holding. The fix is to use a vcpu kick, leaving the interrupt injection to kvm_pmu_sync_hwstate(), like it was doing before the refactoring. We don't just revert, though, because before the kick was request-less, leaving the vcpu exposed to the request-less vcpu kick race, and also because the kick was used unnecessarily from register access handlers. Reviewed-by: Christoffer Dall <cdall@linaro.org> Signed-off-by: Andrew Jones <drjones@redhat.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2017-07-01 19:26:54 +03:00
static void kvm_pmu_update_state(struct kvm_vcpu *vcpu)
KVM: arm/arm64: PMU: remove request-less vcpu kick Refactor PMU overflow handling in order to remove the request-less vcpu kick. Now, since kvm_vgic_inject_irq() uses vcpu requests, there should be no chance that a kick sent at just the wrong time (between the VCPU's call to kvm_pmu_flush_hwstate() and before it enters guest mode) results in a failure for the guest to see updated GIC state until its next exit some time later for some other reason. Signed-off-by: Andrew Jones <drjones@redhat.com> Reviewed-by: Christoffer Dall <cdall@linaro.org> Signed-off-by: Christoffer Dall <cdall@linaro.org>
2017-06-04 15:44:00 +03:00
{
struct kvm_pmu *pmu = &vcpu->arch.pmu;
KVM: arm/arm64: PMU: Fix overflow interrupt injection kvm_pmu_overflow_set() is called from perf's interrupt handler, making the call of kvm_vgic_inject_irq() from it introduced with "KVM: arm/arm64: PMU: remove request-less vcpu kick" a really bad idea, as it's quite easy to try and retake a lock that the interrupted context is already holding. The fix is to use a vcpu kick, leaving the interrupt injection to kvm_pmu_sync_hwstate(), like it was doing before the refactoring. We don't just revert, though, because before the kick was request-less, leaving the vcpu exposed to the request-less vcpu kick race, and also because the kick was used unnecessarily from register access handlers. Reviewed-by: Christoffer Dall <cdall@linaro.org> Signed-off-by: Andrew Jones <drjones@redhat.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2017-07-01 19:26:54 +03:00
bool overflow;
KVM: arm64: Gate kvm_pmu_update_state() on the PMU feature We currently gate the update of the PMU state on the PMU being "ready". The "ready" state is only set to true when the first vcpu run is successful, and if it isn't, we never reach the update code. So the "ready" state is never the right thing to check for, and it should instead be the presence of the PMU feature, which makes a bit more sense. Reviewed-by: Alexandru Elisei <alexandru.elisei@arm.com> Signed-off-by: Marc Zyngier <maz@kernel.org>
2020-11-13 19:41:40 +03:00
if (!kvm_vcpu_has_pmu(vcpu))
KVM: arm/arm64: PMU: Fix overflow interrupt injection kvm_pmu_overflow_set() is called from perf's interrupt handler, making the call of kvm_vgic_inject_irq() from it introduced with "KVM: arm/arm64: PMU: remove request-less vcpu kick" a really bad idea, as it's quite easy to try and retake a lock that the interrupted context is already holding. The fix is to use a vcpu kick, leaving the interrupt injection to kvm_pmu_sync_hwstate(), like it was doing before the refactoring. We don't just revert, though, because before the kick was request-less, leaving the vcpu exposed to the request-less vcpu kick race, and also because the kick was used unnecessarily from register access handlers. Reviewed-by: Christoffer Dall <cdall@linaro.org> Signed-off-by: Andrew Jones <drjones@redhat.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2017-07-01 19:26:54 +03:00
return;
KVM: arm/arm64: PMU: remove request-less vcpu kick Refactor PMU overflow handling in order to remove the request-less vcpu kick. Now, since kvm_vgic_inject_irq() uses vcpu requests, there should be no chance that a kick sent at just the wrong time (between the VCPU's call to kvm_pmu_flush_hwstate() and before it enters guest mode) results in a failure for the guest to see updated GIC state until its next exit some time later for some other reason. Signed-off-by: Andrew Jones <drjones@redhat.com> Reviewed-by: Christoffer Dall <cdall@linaro.org> Signed-off-by: Christoffer Dall <cdall@linaro.org>
2017-06-04 15:44:00 +03:00
KVM: arm/arm64: PMU: Fix overflow interrupt injection kvm_pmu_overflow_set() is called from perf's interrupt handler, making the call of kvm_vgic_inject_irq() from it introduced with "KVM: arm/arm64: PMU: remove request-less vcpu kick" a really bad idea, as it's quite easy to try and retake a lock that the interrupted context is already holding. The fix is to use a vcpu kick, leaving the interrupt injection to kvm_pmu_sync_hwstate(), like it was doing before the refactoring. We don't just revert, though, because before the kick was request-less, leaving the vcpu exposed to the request-less vcpu kick race, and also because the kick was used unnecessarily from register access handlers. Reviewed-by: Christoffer Dall <cdall@linaro.org> Signed-off-by: Andrew Jones <drjones@redhat.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2017-07-01 19:26:54 +03:00
overflow = !!kvm_pmu_overflow_status(vcpu);
KVM: arm/arm64: PMU: remove request-less vcpu kick Refactor PMU overflow handling in order to remove the request-less vcpu kick. Now, since kvm_vgic_inject_irq() uses vcpu requests, there should be no chance that a kick sent at just the wrong time (between the VCPU's call to kvm_pmu_flush_hwstate() and before it enters guest mode) results in a failure for the guest to see updated GIC state until its next exit some time later for some other reason. Signed-off-by: Andrew Jones <drjones@redhat.com> Reviewed-by: Christoffer Dall <cdall@linaro.org> Signed-off-by: Christoffer Dall <cdall@linaro.org>
2017-06-04 15:44:00 +03:00
if (pmu->irq_level == overflow)
return;
pmu->irq_level = overflow;
if (likely(irqchip_in_kernel(vcpu->kvm))) {
int ret = kvm_vgic_inject_irq(vcpu->kvm, vcpu->vcpu_id,
KVM: arm/arm64: PMU: Fix overflow interrupt injection kvm_pmu_overflow_set() is called from perf's interrupt handler, making the call of kvm_vgic_inject_irq() from it introduced with "KVM: arm/arm64: PMU: remove request-less vcpu kick" a really bad idea, as it's quite easy to try and retake a lock that the interrupted context is already holding. The fix is to use a vcpu kick, leaving the interrupt injection to kvm_pmu_sync_hwstate(), like it was doing before the refactoring. We don't just revert, though, because before the kick was request-less, leaving the vcpu exposed to the request-less vcpu kick race, and also because the kick was used unnecessarily from register access handlers. Reviewed-by: Christoffer Dall <cdall@linaro.org> Signed-off-by: Andrew Jones <drjones@redhat.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2017-07-01 19:26:54 +03:00
pmu->irq_num, overflow, pmu);
KVM: arm/arm64: PMU: remove request-less vcpu kick Refactor PMU overflow handling in order to remove the request-less vcpu kick. Now, since kvm_vgic_inject_irq() uses vcpu requests, there should be no chance that a kick sent at just the wrong time (between the VCPU's call to kvm_pmu_flush_hwstate() and before it enters guest mode) results in a failure for the guest to see updated GIC state until its next exit some time later for some other reason. Signed-off-by: Andrew Jones <drjones@redhat.com> Reviewed-by: Christoffer Dall <cdall@linaro.org> Signed-off-by: Christoffer Dall <cdall@linaro.org>
2017-06-04 15:44:00 +03:00
WARN_ON(ret);
}
}
KVM: arm/arm64: Report PMU overflow interrupts to userspace irqchip When not using an in-kernel VGIC, but instead emulating an interrupt controller in userspace, we should report the PMU overflow status to that userspace interrupt controller using the KVM_CAP_ARM_USER_IRQ feature. Reviewed-by: Alexander Graf <agraf@suse.de> Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
2017-02-01 14:51:52 +03:00
bool kvm_pmu_should_notify_user(struct kvm_vcpu *vcpu)
{
struct kvm_pmu *pmu = &vcpu->arch.pmu;
struct kvm_sync_regs *sregs = &vcpu->run->s.regs;
bool run_level = sregs->device_irq_level & KVM_ARM_DEV_PMU;
if (likely(irqchip_in_kernel(vcpu->kvm)))
return false;
return pmu->irq_level != run_level;
}
/*
* Reflect the PMU overflow interrupt output level into the kvm_run structure
*/
void kvm_pmu_update_run(struct kvm_vcpu *vcpu)
{
struct kvm_sync_regs *regs = &vcpu->run->s.regs;
/* Populate the timer bitmap for user space */
regs->device_irq_level &= ~KVM_ARM_DEV_PMU;
if (vcpu->arch.pmu.irq_level)
regs->device_irq_level |= KVM_ARM_DEV_PMU;
}
arm64: KVM: Add PMU overflow interrupt routing When calling perf_event_create_kernel_counter to create perf_event, assign a overflow handler. Then when the perf event overflows, set the corresponding bit of guest PMOVSSET register. If this counter is enabled and its interrupt is enabled as well, kick the vcpu to sync the interrupt. On VM entry, if there is counter overflowed and interrupt level is changed, inject the interrupt with corresponding level. On VM exit, sync the interrupt level as well if it has been changed. Signed-off-by: Shannon Zhao <shannon.zhao@linaro.org> Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> Reviewed-by: Andrew Jones <drjones@redhat.com> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2016-02-26 14:29:19 +03:00
/**
* kvm_pmu_flush_hwstate - flush pmu state to cpu
* @vcpu: The vcpu pointer
*
* Check if the PMU has overflowed while we were running in the host, and inject
* an interrupt if that was the case.
*/
void kvm_pmu_flush_hwstate(struct kvm_vcpu *vcpu)
{
kvm_pmu_update_state(vcpu);
}
/**
* kvm_pmu_sync_hwstate - sync pmu state from cpu
* @vcpu: The vcpu pointer
*
* Check if the PMU has overflowed while we were running in the guest, and
* inject an interrupt if that was the case.
*/
void kvm_pmu_sync_hwstate(struct kvm_vcpu *vcpu)
{
kvm_pmu_update_state(vcpu);
}
KVM: arm64: pmu: Make overflow handler NMI safe kvm_vcpu_kick() is not NMI safe. When the overflow handler is called from NMI context, defer waking the vcpu to an irq_work queue. A vcpu can be freed while it's not running by kvm_destroy_vm(). Prevent running the irq_work for a non-existent vcpu by calling irq_work_sync() on the PMU destroy path. [Alexandru E.: Added irq_work_sync()] Signed-off-by: Julien Thierry <julien.thierry@arm.com> Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com> Tested-by: Sumit Garg <sumit.garg@linaro.org> (Developerbox) Cc: Julien Thierry <julien.thierry.kdev@gmail.com> Cc: Marc Zyngier <marc.zyngier@arm.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: James Morse <james.morse@arm.com> Cc: Suzuki K Pouloze <suzuki.poulose@arm.com> Cc: kvm@vger.kernel.org Cc: kvmarm@lists.cs.columbia.edu Link: https://lore.kernel.org/r/20200924110706.254996-6-alexandru.elisei@arm.com Signed-off-by: Will Deacon <will@kernel.org>
2020-09-24 14:07:04 +03:00
/**
* When perf interrupt is an NMI, we cannot safely notify the vcpu corresponding
* to the event.
* This is why we need a callback to do it once outside of the NMI context.
*/
static void kvm_pmu_perf_overflow_notify_vcpu(struct irq_work *work)
{
struct kvm_vcpu *vcpu;
KVM: arm64: PMU: Simplify vcpu computation on perf overflow notification The way we compute the target vcpu on getting an overflow is a bit odd, as we use the PMC array as an anchor for kvm_pmc_to_vcpu, while we could directly compute the correct address. Get rid of the intermediate step and directly compute the target vcpu. Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221113163832.3154370-16-maz@kernel.org
2022-11-13 19:38:31 +03:00
vcpu = container_of(work, struct kvm_vcpu, arch.pmu.overflow_work);
KVM: arm64: pmu: Make overflow handler NMI safe kvm_vcpu_kick() is not NMI safe. When the overflow handler is called from NMI context, defer waking the vcpu to an irq_work queue. A vcpu can be freed while it's not running by kvm_destroy_vm(). Prevent running the irq_work for a non-existent vcpu by calling irq_work_sync() on the PMU destroy path. [Alexandru E.: Added irq_work_sync()] Signed-off-by: Julien Thierry <julien.thierry@arm.com> Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com> Tested-by: Sumit Garg <sumit.garg@linaro.org> (Developerbox) Cc: Julien Thierry <julien.thierry.kdev@gmail.com> Cc: Marc Zyngier <marc.zyngier@arm.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: James Morse <james.morse@arm.com> Cc: Suzuki K Pouloze <suzuki.poulose@arm.com> Cc: kvm@vger.kernel.org Cc: kvmarm@lists.cs.columbia.edu Link: https://lore.kernel.org/r/20200924110706.254996-6-alexandru.elisei@arm.com Signed-off-by: Will Deacon <will@kernel.org>
2020-09-24 14:07:04 +03:00
kvm_vcpu_kick(vcpu);
}
KVM: arm64: PMU: Align chained counter implementation with architecture pseudocode Ricardo recently pointed out that the PMU chained counter emulation in KVM wasn't quite behaving like the one on actual hardware, in the sense that a chained counter would expose an overflow on both halves of a chained counter, while KVM would only expose the overflow on the top half. The difference is subtle, but significant. What does the architecture say (DDI0087 H.a): - Up to PMUv3p4, all counters but the cycle counter are 32bit - A 32bit counter that overflows generates a CHAIN event on the adjacent counter after exposing its own overflow status - The CHAIN event is accounted if the counter is correctly configured (CHAIN event selected and counter enabled) This all means that our current implementation (which uses 64bit perf events) prevents us from emulating this overflow on the lower half. How to fix this? By implementing the above, to the letter. This largely results in code deletion, removing the notions of "counter pair", "chained counters", and "canonical counter". The code is further restructured to make the CHAIN handling similar to SWINC, as the two are now extremely similar in behaviour. Reported-by: Ricardo Koller <ricarkol@google.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Reviewed-by: Reiji Watanabe <reijiw@google.com> Link: https://lore.kernel.org/r/20221113163832.3154370-3-maz@kernel.org
2022-11-13 19:38:18 +03:00
/*
* Perform an increment on any of the counters described in @mask,
* generating the overflow if required, and propagate it as a chained
* event if possible.
*/
static void kvm_pmu_counter_increment(struct kvm_vcpu *vcpu,
unsigned long mask, u32 event)
{
int i;
if (!(__vcpu_sys_reg(vcpu, PMCR_EL0) & ARMV8_PMU_PMCR_E))
return;
/* Weed out disabled counters */
mask &= __vcpu_sys_reg(vcpu, PMCNTENSET_EL0);
for_each_set_bit(i, &mask, ARMV8_PMU_CYCLE_IDX) {
KVM: arm64: PMU: Make kvm_pmc the main data structure The PMU code has historically been torn between referencing a counter as a pair vcpu+index or as the PMC pointer. Given that it is pretty easy to go from one representation to the other, standardise on the latter which, IMHO, makes the code slightly more readable. YMMV. Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221113163832.3154370-17-maz@kernel.org
2022-11-13 19:38:32 +03:00
struct kvm_pmc *pmc = kvm_vcpu_idx_to_pmc(vcpu, i);
KVM: arm64: PMU: Align chained counter implementation with architecture pseudocode Ricardo recently pointed out that the PMU chained counter emulation in KVM wasn't quite behaving like the one on actual hardware, in the sense that a chained counter would expose an overflow on both halves of a chained counter, while KVM would only expose the overflow on the top half. The difference is subtle, but significant. What does the architecture say (DDI0087 H.a): - Up to PMUv3p4, all counters but the cycle counter are 32bit - A 32bit counter that overflows generates a CHAIN event on the adjacent counter after exposing its own overflow status - The CHAIN event is accounted if the counter is correctly configured (CHAIN event selected and counter enabled) This all means that our current implementation (which uses 64bit perf events) prevents us from emulating this overflow on the lower half. How to fix this? By implementing the above, to the letter. This largely results in code deletion, removing the notions of "counter pair", "chained counters", and "canonical counter". The code is further restructured to make the CHAIN handling similar to SWINC, as the two are now extremely similar in behaviour. Reported-by: Ricardo Koller <ricarkol@google.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Reviewed-by: Reiji Watanabe <reijiw@google.com> Link: https://lore.kernel.org/r/20221113163832.3154370-3-maz@kernel.org
2022-11-13 19:38:18 +03:00
u64 type, reg;
/* Filter on event type */
KVM: arm64: PMU: Add counter_index_to_*reg() helpers In order to reduce the boilerplate code, add two helpers returning the counter register index (resp. the event register) in the vcpu register file from the counter index. Reviewed-by: Oliver Upton <oliver.upton@linux.dev> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221113163832.3154370-8-maz@kernel.org
2022-11-13 19:38:23 +03:00
type = __vcpu_sys_reg(vcpu, counter_index_to_evtreg(i));
KVM: arm64: PMU: Align chained counter implementation with architecture pseudocode Ricardo recently pointed out that the PMU chained counter emulation in KVM wasn't quite behaving like the one on actual hardware, in the sense that a chained counter would expose an overflow on both halves of a chained counter, while KVM would only expose the overflow on the top half. The difference is subtle, but significant. What does the architecture say (DDI0087 H.a): - Up to PMUv3p4, all counters but the cycle counter are 32bit - A 32bit counter that overflows generates a CHAIN event on the adjacent counter after exposing its own overflow status - The CHAIN event is accounted if the counter is correctly configured (CHAIN event selected and counter enabled) This all means that our current implementation (which uses 64bit perf events) prevents us from emulating this overflow on the lower half. How to fix this? By implementing the above, to the letter. This largely results in code deletion, removing the notions of "counter pair", "chained counters", and "canonical counter". The code is further restructured to make the CHAIN handling similar to SWINC, as the two are now extremely similar in behaviour. Reported-by: Ricardo Koller <ricarkol@google.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Reviewed-by: Reiji Watanabe <reijiw@google.com> Link: https://lore.kernel.org/r/20221113163832.3154370-3-maz@kernel.org
2022-11-13 19:38:18 +03:00
type &= kvm_pmu_event_mask(vcpu->kvm);
if (type != event)
continue;
/* Increment this counter */
KVM: arm64: PMU: Add counter_index_to_*reg() helpers In order to reduce the boilerplate code, add two helpers returning the counter register index (resp. the event register) in the vcpu register file from the counter index. Reviewed-by: Oliver Upton <oliver.upton@linux.dev> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221113163832.3154370-8-maz@kernel.org
2022-11-13 19:38:23 +03:00
reg = __vcpu_sys_reg(vcpu, counter_index_to_reg(i)) + 1;
KVM: arm64: PMU: Make kvm_pmc the main data structure The PMU code has historically been torn between referencing a counter as a pair vcpu+index or as the PMC pointer. Given that it is pretty easy to go from one representation to the other, standardise on the latter which, IMHO, makes the code slightly more readable. YMMV. Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221113163832.3154370-17-maz@kernel.org
2022-11-13 19:38:32 +03:00
if (!kvm_pmc_is_64bit(pmc))
KVM: arm64: PMU: Only narrow counters that are not 64bit wide The current PMU emulation sometimes narrows counters to 32bit if the counter isn't the cycle counter. As this is going to change with PMUv3p5 where the counters are all 64bit, fix the couple of cases where this happens unconditionally. Signed-off-by: Marc Zyngier <maz@kernel.org> Reviewed-by: Reiji Watanabe <reijiw@google.com> Link: https://lore.kernel.org/r/20221113163832.3154370-7-maz@kernel.org
2022-11-13 19:38:22 +03:00
reg = lower_32_bits(reg);
KVM: arm64: PMU: Add counter_index_to_*reg() helpers In order to reduce the boilerplate code, add two helpers returning the counter register index (resp. the event register) in the vcpu register file from the counter index. Reviewed-by: Oliver Upton <oliver.upton@linux.dev> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221113163832.3154370-8-maz@kernel.org
2022-11-13 19:38:23 +03:00
__vcpu_sys_reg(vcpu, counter_index_to_reg(i)) = reg;
KVM: arm64: PMU: Align chained counter implementation with architecture pseudocode Ricardo recently pointed out that the PMU chained counter emulation in KVM wasn't quite behaving like the one on actual hardware, in the sense that a chained counter would expose an overflow on both halves of a chained counter, while KVM would only expose the overflow on the top half. The difference is subtle, but significant. What does the architecture say (DDI0087 H.a): - Up to PMUv3p4, all counters but the cycle counter are 32bit - A 32bit counter that overflows generates a CHAIN event on the adjacent counter after exposing its own overflow status - The CHAIN event is accounted if the counter is correctly configured (CHAIN event selected and counter enabled) This all means that our current implementation (which uses 64bit perf events) prevents us from emulating this overflow on the lower half. How to fix this? By implementing the above, to the letter. This largely results in code deletion, removing the notions of "counter pair", "chained counters", and "canonical counter". The code is further restructured to make the CHAIN handling similar to SWINC, as the two are now extremely similar in behaviour. Reported-by: Ricardo Koller <ricarkol@google.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Reviewed-by: Reiji Watanabe <reijiw@google.com> Link: https://lore.kernel.org/r/20221113163832.3154370-3-maz@kernel.org
2022-11-13 19:38:18 +03:00
KVM: arm64: PMU: Narrow the overflow checking when required For 64bit counters that overflow on a 32bit boundary, make sure we only check the bottom 32bit to generate a CHAIN event. Signed-off-by: Marc Zyngier <maz@kernel.org> Reviewed-by: Reiji Watanabe <reijiw@google.com> Link: https://lore.kernel.org/r/20221113163832.3154370-6-maz@kernel.org
2022-11-13 19:38:21 +03:00
/* No overflow? move on */
KVM: arm64: PMU: Make kvm_pmc the main data structure The PMU code has historically been torn between referencing a counter as a pair vcpu+index or as the PMC pointer. Given that it is pretty easy to go from one representation to the other, standardise on the latter which, IMHO, makes the code slightly more readable. YMMV. Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221113163832.3154370-17-maz@kernel.org
2022-11-13 19:38:32 +03:00
if (kvm_pmc_has_64bit_overflow(pmc) ? reg : lower_32_bits(reg))
KVM: arm64: PMU: Align chained counter implementation with architecture pseudocode Ricardo recently pointed out that the PMU chained counter emulation in KVM wasn't quite behaving like the one on actual hardware, in the sense that a chained counter would expose an overflow on both halves of a chained counter, while KVM would only expose the overflow on the top half. The difference is subtle, but significant. What does the architecture say (DDI0087 H.a): - Up to PMUv3p4, all counters but the cycle counter are 32bit - A 32bit counter that overflows generates a CHAIN event on the adjacent counter after exposing its own overflow status - The CHAIN event is accounted if the counter is correctly configured (CHAIN event selected and counter enabled) This all means that our current implementation (which uses 64bit perf events) prevents us from emulating this overflow on the lower half. How to fix this? By implementing the above, to the letter. This largely results in code deletion, removing the notions of "counter pair", "chained counters", and "canonical counter". The code is further restructured to make the CHAIN handling similar to SWINC, as the two are now extremely similar in behaviour. Reported-by: Ricardo Koller <ricarkol@google.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Reviewed-by: Reiji Watanabe <reijiw@google.com> Link: https://lore.kernel.org/r/20221113163832.3154370-3-maz@kernel.org
2022-11-13 19:38:18 +03:00
continue;
/* Mark overflow */
__vcpu_sys_reg(vcpu, PMOVSSET_EL0) |= BIT(i);
KVM: arm64: PMU: Make kvm_pmc the main data structure The PMU code has historically been torn between referencing a counter as a pair vcpu+index or as the PMC pointer. Given that it is pretty easy to go from one representation to the other, standardise on the latter which, IMHO, makes the code slightly more readable. YMMV. Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221113163832.3154370-17-maz@kernel.org
2022-11-13 19:38:32 +03:00
if (kvm_pmu_counter_can_chain(pmc))
KVM: arm64: PMU: Align chained counter implementation with architecture pseudocode Ricardo recently pointed out that the PMU chained counter emulation in KVM wasn't quite behaving like the one on actual hardware, in the sense that a chained counter would expose an overflow on both halves of a chained counter, while KVM would only expose the overflow on the top half. The difference is subtle, but significant. What does the architecture say (DDI0087 H.a): - Up to PMUv3p4, all counters but the cycle counter are 32bit - A 32bit counter that overflows generates a CHAIN event on the adjacent counter after exposing its own overflow status - The CHAIN event is accounted if the counter is correctly configured (CHAIN event selected and counter enabled) This all means that our current implementation (which uses 64bit perf events) prevents us from emulating this overflow on the lower half. How to fix this? By implementing the above, to the letter. This largely results in code deletion, removing the notions of "counter pair", "chained counters", and "canonical counter". The code is further restructured to make the CHAIN handling similar to SWINC, as the two are now extremely similar in behaviour. Reported-by: Ricardo Koller <ricarkol@google.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Reviewed-by: Reiji Watanabe <reijiw@google.com> Link: https://lore.kernel.org/r/20221113163832.3154370-3-maz@kernel.org
2022-11-13 19:38:18 +03:00
kvm_pmu_counter_increment(vcpu, BIT(i + 1),
ARMV8_PMUV3_PERFCTR_CHAIN);
}
}
KVM: arm64: PMU: Distinguish between 64bit counter and 64bit overflow The PMU architecture makes a subtle difference between a 64bit counter and a counter that has a 64bit overflow. This is for example the case of the cycle counter, which can generate an overflow on a 32bit boundary if PMCR_EL0.LC==0 despite the accumulation being done on 64 bits. Use this distinction in the few cases where it matters in the code, as we will reuse this with PMUv3p5 long counters. Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221113163832.3154370-5-maz@kernel.org
2022-11-13 19:38:20 +03:00
/* Compute the sample period for a given counter value */
KVM: arm64: PMU: Make kvm_pmc the main data structure The PMU code has historically been torn between referencing a counter as a pair vcpu+index or as the PMC pointer. Given that it is pretty easy to go from one representation to the other, standardise on the latter which, IMHO, makes the code slightly more readable. YMMV. Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221113163832.3154370-17-maz@kernel.org
2022-11-13 19:38:32 +03:00
static u64 compute_period(struct kvm_pmc *pmc, u64 counter)
KVM: arm64: PMU: Distinguish between 64bit counter and 64bit overflow The PMU architecture makes a subtle difference between a 64bit counter and a counter that has a 64bit overflow. This is for example the case of the cycle counter, which can generate an overflow on a 32bit boundary if PMCR_EL0.LC==0 despite the accumulation being done on 64 bits. Use this distinction in the few cases where it matters in the code, as we will reuse this with PMUv3p5 long counters. Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221113163832.3154370-5-maz@kernel.org
2022-11-13 19:38:20 +03:00
{
u64 val;
KVM: arm64: PMU: Fix period computation for 64bit counters with 32bit overflow Fix the bogus masking when computing the period of a 64bit counter with 32bit overflow. It really should be treated like a 32bit counter for the purpose of the period. Reported-by: Ricardo Koller <ricarkol@google.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/Y4jbosgHbUDI0WF4@google.com
2022-12-05 15:05:51 +03:00
if (kvm_pmc_is_64bit(pmc) && kvm_pmc_has_64bit_overflow(pmc))
val = (-counter) & GENMASK(63, 0);
else
KVM: arm64: PMU: Distinguish between 64bit counter and 64bit overflow The PMU architecture makes a subtle difference between a 64bit counter and a counter that has a 64bit overflow. This is for example the case of the cycle counter, which can generate an overflow on a 32bit boundary if PMCR_EL0.LC==0 despite the accumulation being done on 64 bits. Use this distinction in the few cases where it matters in the code, as we will reuse this with PMUv3p5 long counters. Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221113163832.3154370-5-maz@kernel.org
2022-11-13 19:38:20 +03:00
val = (-counter) & GENMASK(31, 0);
return val;
}
arm64: KVM: Add PMU overflow interrupt routing When calling perf_event_create_kernel_counter to create perf_event, assign a overflow handler. Then when the perf event overflows, set the corresponding bit of guest PMOVSSET register. If this counter is enabled and its interrupt is enabled as well, kick the vcpu to sync the interrupt. On VM entry, if there is counter overflowed and interrupt level is changed, inject the interrupt with corresponding level. On VM exit, sync the interrupt level as well if it has been changed. Signed-off-by: Shannon Zhao <shannon.zhao@linaro.org> Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> Reviewed-by: Andrew Jones <drjones@redhat.com> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2016-02-26 14:29:19 +03:00
/**
KVM: arm/arm64: PMU: Fix overflow interrupt injection kvm_pmu_overflow_set() is called from perf's interrupt handler, making the call of kvm_vgic_inject_irq() from it introduced with "KVM: arm/arm64: PMU: remove request-less vcpu kick" a really bad idea, as it's quite easy to try and retake a lock that the interrupted context is already holding. The fix is to use a vcpu kick, leaving the interrupt injection to kvm_pmu_sync_hwstate(), like it was doing before the refactoring. We don't just revert, though, because before the kick was request-less, leaving the vcpu exposed to the request-less vcpu kick race, and also because the kick was used unnecessarily from register access handlers. Reviewed-by: Christoffer Dall <cdall@linaro.org> Signed-off-by: Andrew Jones <drjones@redhat.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2017-07-01 19:26:54 +03:00
* When the perf event overflows, set the overflow status and inform the vcpu.
arm64: KVM: Add PMU overflow interrupt routing When calling perf_event_create_kernel_counter to create perf_event, assign a overflow handler. Then when the perf event overflows, set the corresponding bit of guest PMOVSSET register. If this counter is enabled and its interrupt is enabled as well, kick the vcpu to sync the interrupt. On VM entry, if there is counter overflowed and interrupt level is changed, inject the interrupt with corresponding level. On VM exit, sync the interrupt level as well if it has been changed. Signed-off-by: Shannon Zhao <shannon.zhao@linaro.org> Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> Reviewed-by: Andrew Jones <drjones@redhat.com> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2016-02-26 14:29:19 +03:00
*/
static void kvm_pmu_perf_overflow(struct perf_event *perf_event,
struct perf_sample_data *data,
struct pt_regs *regs)
{
struct kvm_pmc *pmc = perf_event->overflow_handler_context;
KVM: arm64: pmu: Reset sample period on overflow handling The PMU emulation code uses the perf event sample period to trigger the overflow detection. This works fine for the *first* overflow handling, but results in a huge number of interrupts on the host, unrelated to the number of interrupts handled in the guest (a x20 factor is pretty common for the cycle counter). On a slow system (such as a SW model), this can result in the guest only making forward progress at a glacial pace. It turns out that the clue is in the name. The sample period is exactly that: a period. And once the an overflow has occured, the following period should be the full width of the associated counter, instead of whatever the guest had initially programed. Reset the sample period to the architected value in the overflow handler, which now results in a number of host interrupts that is much closer to the number of interrupts in the guest. Fixes: b02386eb7dac ("arm64: KVM: Add PMU overflow interrupt routing") Reviewed-by: Andrew Murray <andrew.murray@arm.com> Signed-off-by: Marc Zyngier <maz@kernel.org>
2019-10-06 12:28:50 +03:00
struct arm_pmu *cpu_pmu = to_arm_pmu(perf_event->pmu);
arm64: KVM: Add PMU overflow interrupt routing When calling perf_event_create_kernel_counter to create perf_event, assign a overflow handler. Then when the perf event overflows, set the corresponding bit of guest PMOVSSET register. If this counter is enabled and its interrupt is enabled as well, kick the vcpu to sync the interrupt. On VM entry, if there is counter overflowed and interrupt level is changed, inject the interrupt with corresponding level. On VM exit, sync the interrupt level as well if it has been changed. Signed-off-by: Shannon Zhao <shannon.zhao@linaro.org> Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> Reviewed-by: Andrew Jones <drjones@redhat.com> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2016-02-26 14:29:19 +03:00
struct kvm_vcpu *vcpu = kvm_pmc_to_vcpu(pmc);
int idx = pmc->idx;
KVM: arm64: pmu: Reset sample period on overflow handling The PMU emulation code uses the perf event sample period to trigger the overflow detection. This works fine for the *first* overflow handling, but results in a huge number of interrupts on the host, unrelated to the number of interrupts handled in the guest (a x20 factor is pretty common for the cycle counter). On a slow system (such as a SW model), this can result in the guest only making forward progress at a glacial pace. It turns out that the clue is in the name. The sample period is exactly that: a period. And once the an overflow has occured, the following period should be the full width of the associated counter, instead of whatever the guest had initially programed. Reset the sample period to the architected value in the overflow handler, which now results in a number of host interrupts that is much closer to the number of interrupts in the guest. Fixes: b02386eb7dac ("arm64: KVM: Add PMU overflow interrupt routing") Reviewed-by: Andrew Murray <andrew.murray@arm.com> Signed-off-by: Marc Zyngier <maz@kernel.org>
2019-10-06 12:28:50 +03:00
u64 period;
cpu_pmu->pmu.stop(perf_event, PERF_EF_UPDATE);
/*
* Reset the sample period to the architectural limit,
* i.e. the point where the counter overflows.
*/
KVM: arm64: PMU: Make kvm_pmc the main data structure The PMU code has historically been torn between referencing a counter as a pair vcpu+index or as the PMC pointer. Given that it is pretty easy to go from one representation to the other, standardise on the latter which, IMHO, makes the code slightly more readable. YMMV. Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221113163832.3154370-17-maz@kernel.org
2022-11-13 19:38:32 +03:00
period = compute_period(pmc, local64_read(&perf_event->count));
KVM: arm64: pmu: Reset sample period on overflow handling The PMU emulation code uses the perf event sample period to trigger the overflow detection. This works fine for the *first* overflow handling, but results in a huge number of interrupts on the host, unrelated to the number of interrupts handled in the guest (a x20 factor is pretty common for the cycle counter). On a slow system (such as a SW model), this can result in the guest only making forward progress at a glacial pace. It turns out that the clue is in the name. The sample period is exactly that: a period. And once the an overflow has occured, the following period should be the full width of the associated counter, instead of whatever the guest had initially programed. Reset the sample period to the architected value in the overflow handler, which now results in a number of host interrupts that is much closer to the number of interrupts in the guest. Fixes: b02386eb7dac ("arm64: KVM: Add PMU overflow interrupt routing") Reviewed-by: Andrew Murray <andrew.murray@arm.com> Signed-off-by: Marc Zyngier <maz@kernel.org>
2019-10-06 12:28:50 +03:00
local64_set(&perf_event->hw.period_left, 0);
perf_event->attr.sample_period = period;
perf_event->hw.sample_period = period;
arm64: KVM: Add PMU overflow interrupt routing When calling perf_event_create_kernel_counter to create perf_event, assign a overflow handler. Then when the perf event overflows, set the corresponding bit of guest PMOVSSET register. If this counter is enabled and its interrupt is enabled as well, kick the vcpu to sync the interrupt. On VM entry, if there is counter overflowed and interrupt level is changed, inject the interrupt with corresponding level. On VM exit, sync the interrupt level as well if it has been changed. Signed-off-by: Shannon Zhao <shannon.zhao@linaro.org> Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> Reviewed-by: Andrew Jones <drjones@redhat.com> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2016-02-26 14:29:19 +03:00
KVM: arm64: Rewrite system register accessors to read/write functions Currently we access the system registers array via the vcpu_sys_reg() macro. However, we are about to change the behavior to some times modify the register file directly, so let's change this to two primitives: * Accessor macros vcpu_write_sys_reg() and vcpu_read_sys_reg() * Direct array access macro __vcpu_sys_reg() The accessor macros should be used in places where the code needs to access the currently loaded VCPU's state as observed by the guest. For example, when trapping on cache related registers, a write to a system register should go directly to the VCPU version of the register. The direct array access macro can be used in places where the VCPU is known to never be running (for example userspace access) or for registers which are never context switched (for example all the PMU system registers). This rewrites all users of vcpu_sys_regs to one of the macros described above. No functional change. Acked-by: Marc Zyngier <marc.zyngier@arm.com> Reviewed-by: Andrew Jones <drjones@redhat.com> Signed-off-by: Christoffer Dall <cdall@cs.columbia.edu> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2016-03-16 17:38:53 +03:00
__vcpu_sys_reg(vcpu, PMOVSSET_EL0) |= BIT(idx);
KVM: arm/arm64: PMU: Fix overflow interrupt injection kvm_pmu_overflow_set() is called from perf's interrupt handler, making the call of kvm_vgic_inject_irq() from it introduced with "KVM: arm/arm64: PMU: remove request-less vcpu kick" a really bad idea, as it's quite easy to try and retake a lock that the interrupted context is already holding. The fix is to use a vcpu kick, leaving the interrupt injection to kvm_pmu_sync_hwstate(), like it was doing before the refactoring. We don't just revert, though, because before the kick was request-less, leaving the vcpu exposed to the request-less vcpu kick race, and also because the kick was used unnecessarily from register access handlers. Reviewed-by: Christoffer Dall <cdall@linaro.org> Signed-off-by: Andrew Jones <drjones@redhat.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2017-07-01 19:26:54 +03:00
KVM: arm64: PMU: Make kvm_pmc the main data structure The PMU code has historically been torn between referencing a counter as a pair vcpu+index or as the PMC pointer. Given that it is pretty easy to go from one representation to the other, standardise on the latter which, IMHO, makes the code slightly more readable. YMMV. Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221113163832.3154370-17-maz@kernel.org
2022-11-13 19:38:32 +03:00
if (kvm_pmu_counter_can_chain(pmc))
KVM: arm64: PMU: Align chained counter implementation with architecture pseudocode Ricardo recently pointed out that the PMU chained counter emulation in KVM wasn't quite behaving like the one on actual hardware, in the sense that a chained counter would expose an overflow on both halves of a chained counter, while KVM would only expose the overflow on the top half. The difference is subtle, but significant. What does the architecture say (DDI0087 H.a): - Up to PMUv3p4, all counters but the cycle counter are 32bit - A 32bit counter that overflows generates a CHAIN event on the adjacent counter after exposing its own overflow status - The CHAIN event is accounted if the counter is correctly configured (CHAIN event selected and counter enabled) This all means that our current implementation (which uses 64bit perf events) prevents us from emulating this overflow on the lower half. How to fix this? By implementing the above, to the letter. This largely results in code deletion, removing the notions of "counter pair", "chained counters", and "canonical counter". The code is further restructured to make the CHAIN handling similar to SWINC, as the two are now extremely similar in behaviour. Reported-by: Ricardo Koller <ricarkol@google.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Reviewed-by: Reiji Watanabe <reijiw@google.com> Link: https://lore.kernel.org/r/20221113163832.3154370-3-maz@kernel.org
2022-11-13 19:38:18 +03:00
kvm_pmu_counter_increment(vcpu, BIT(idx + 1),
ARMV8_PMUV3_PERFCTR_CHAIN);
KVM: arm/arm64: PMU: Fix overflow interrupt injection kvm_pmu_overflow_set() is called from perf's interrupt handler, making the call of kvm_vgic_inject_irq() from it introduced with "KVM: arm/arm64: PMU: remove request-less vcpu kick" a really bad idea, as it's quite easy to try and retake a lock that the interrupted context is already holding. The fix is to use a vcpu kick, leaving the interrupt injection to kvm_pmu_sync_hwstate(), like it was doing before the refactoring. We don't just revert, though, because before the kick was request-less, leaving the vcpu exposed to the request-less vcpu kick race, and also because the kick was used unnecessarily from register access handlers. Reviewed-by: Christoffer Dall <cdall@linaro.org> Signed-off-by: Andrew Jones <drjones@redhat.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2017-07-01 19:26:54 +03:00
if (kvm_pmu_overflow_status(vcpu)) {
kvm_make_request(KVM_REQ_IRQ_PENDING, vcpu);
KVM: arm64: pmu: Make overflow handler NMI safe kvm_vcpu_kick() is not NMI safe. When the overflow handler is called from NMI context, defer waking the vcpu to an irq_work queue. A vcpu can be freed while it's not running by kvm_destroy_vm(). Prevent running the irq_work for a non-existent vcpu by calling irq_work_sync() on the PMU destroy path. [Alexandru E.: Added irq_work_sync()] Signed-off-by: Julien Thierry <julien.thierry@arm.com> Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com> Tested-by: Sumit Garg <sumit.garg@linaro.org> (Developerbox) Cc: Julien Thierry <julien.thierry.kdev@gmail.com> Cc: Marc Zyngier <marc.zyngier@arm.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: James Morse <james.morse@arm.com> Cc: Suzuki K Pouloze <suzuki.poulose@arm.com> Cc: kvm@vger.kernel.org Cc: kvmarm@lists.cs.columbia.edu Link: https://lore.kernel.org/r/20200924110706.254996-6-alexandru.elisei@arm.com Signed-off-by: Will Deacon <will@kernel.org>
2020-09-24 14:07:04 +03:00
if (!in_nmi())
kvm_vcpu_kick(vcpu);
else
irq_work_queue(&vcpu->arch.pmu.overflow_work);
KVM: arm/arm64: PMU: Fix overflow interrupt injection kvm_pmu_overflow_set() is called from perf's interrupt handler, making the call of kvm_vgic_inject_irq() from it introduced with "KVM: arm/arm64: PMU: remove request-less vcpu kick" a really bad idea, as it's quite easy to try and retake a lock that the interrupted context is already holding. The fix is to use a vcpu kick, leaving the interrupt injection to kvm_pmu_sync_hwstate(), like it was doing before the refactoring. We don't just revert, though, because before the kick was request-less, leaving the vcpu exposed to the request-less vcpu kick race, and also because the kick was used unnecessarily from register access handlers. Reviewed-by: Christoffer Dall <cdall@linaro.org> Signed-off-by: Andrew Jones <drjones@redhat.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2017-07-01 19:26:54 +03:00
}
KVM: arm64: pmu: Reset sample period on overflow handling The PMU emulation code uses the perf event sample period to trigger the overflow detection. This works fine for the *first* overflow handling, but results in a huge number of interrupts on the host, unrelated to the number of interrupts handled in the guest (a x20 factor is pretty common for the cycle counter). On a slow system (such as a SW model), this can result in the guest only making forward progress at a glacial pace. It turns out that the clue is in the name. The sample period is exactly that: a period. And once the an overflow has occured, the following period should be the full width of the associated counter, instead of whatever the guest had initially programed. Reset the sample period to the architected value in the overflow handler, which now results in a number of host interrupts that is much closer to the number of interrupts in the guest. Fixes: b02386eb7dac ("arm64: KVM: Add PMU overflow interrupt routing") Reviewed-by: Andrew Murray <andrew.murray@arm.com> Signed-off-by: Marc Zyngier <maz@kernel.org>
2019-10-06 12:28:50 +03:00
cpu_pmu->pmu.start(perf_event, PERF_EF_RELOAD);
arm64: KVM: Add PMU overflow interrupt routing When calling perf_event_create_kernel_counter to create perf_event, assign a overflow handler. Then when the perf event overflows, set the corresponding bit of guest PMOVSSET register. If this counter is enabled and its interrupt is enabled as well, kick the vcpu to sync the interrupt. On VM entry, if there is counter overflowed and interrupt level is changed, inject the interrupt with corresponding level. On VM exit, sync the interrupt level as well if it has been changed. Signed-off-by: Shannon Zhao <shannon.zhao@linaro.org> Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> Reviewed-by: Andrew Jones <drjones@redhat.com> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2016-02-26 14:29:19 +03:00
}
arm64: KVM: Add access handler for PMSWINC register Add access handler which emulates writing and reading PMSWINC register and add support for creating software increment event. Signed-off-by: Shannon Zhao <shannon.zhao@linaro.org> Reviewed-by: Andrew Jones <drjones@redhat.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-09-08 10:49:39 +03:00
/**
* kvm_pmu_software_increment - do software increment
* @vcpu: The vcpu pointer
* @val: the value guest writes to PMSWINC register
*/
void kvm_pmu_software_increment(struct kvm_vcpu *vcpu, u64 val)
{
KVM: arm64: PMU: Align chained counter implementation with architecture pseudocode Ricardo recently pointed out that the PMU chained counter emulation in KVM wasn't quite behaving like the one on actual hardware, in the sense that a chained counter would expose an overflow on both halves of a chained counter, while KVM would only expose the overflow on the top half. The difference is subtle, but significant. What does the architecture say (DDI0087 H.a): - Up to PMUv3p4, all counters but the cycle counter are 32bit - A 32bit counter that overflows generates a CHAIN event on the adjacent counter after exposing its own overflow status - The CHAIN event is accounted if the counter is correctly configured (CHAIN event selected and counter enabled) This all means that our current implementation (which uses 64bit perf events) prevents us from emulating this overflow on the lower half. How to fix this? By implementing the above, to the letter. This largely results in code deletion, removing the notions of "counter pair", "chained counters", and "canonical counter". The code is further restructured to make the CHAIN handling similar to SWINC, as the two are now extremely similar in behaviour. Reported-by: Ricardo Koller <ricarkol@google.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Reviewed-by: Reiji Watanabe <reijiw@google.com> Link: https://lore.kernel.org/r/20221113163832.3154370-3-maz@kernel.org
2022-11-13 19:38:18 +03:00
kvm_pmu_counter_increment(vcpu, val, ARMV8_PMUV3_PERFCTR_SW_INCR);
arm64: KVM: Add access handler for PMSWINC register Add access handler which emulates writing and reading PMSWINC register and add support for creating software increment event. Signed-off-by: Shannon Zhao <shannon.zhao@linaro.org> Reviewed-by: Andrew Jones <drjones@redhat.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-09-08 10:49:39 +03:00
}
arm64: KVM: Add helper to handle PMCR register bits According to ARMv8 spec, when writing 1 to PMCR.E, all counters are enabled by PMCNTENSET, while writing 0 to PMCR.E, all counters are disabled. When writing 1 to PMCR.P, reset all event counters, not including PMCCNTR, to zero. When writing 1 to PMCR.C, reset PMCCNTR to zero. Signed-off-by: Shannon Zhao <shannon.zhao@linaro.org> Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-10-28 07:10:30 +03:00
/**
* kvm_pmu_handle_pmcr - handle PMCR register
* @vcpu: The vcpu pointer
* @val: the value guest writes to PMCR register
*/
void kvm_pmu_handle_pmcr(struct kvm_vcpu *vcpu, u64 val)
{
int i;
KVM/arm64: Don't emulate a PMU for 32-bit guests if feature not set kvm->arch.arm_pmu is set when userspace attempts to set the first PMU attribute. As certain attributes are mandatory, arm_pmu ends up always being set to a valid arm_pmu, otherwise KVM will refuse to run the VCPU. However, this only happens if the VCPU has the PMU feature. If the VCPU doesn't have the feature bit set, kvm->arch.arm_pmu will be left uninitialized and equal to NULL. KVM doesn't do ID register emulation for 32-bit guests and accesses to the PMU registers aren't gated by the pmu_visibility() function. This is done to prevent injecting unexpected undefined exceptions in guests which have detected the presence of a hardware PMU. But even though the VCPU feature is missing, KVM still attempts to emulate certain aspects of the PMU when PMU registers are accessed. This leads to a NULL pointer dereference like this one, which happens on an odroid-c4 board when running the kvm-unit-tests pmu-cycle-counter test with kvmtool and without the PMU feature being set: [ 454.402699] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000150 [ 454.405865] Mem abort info: [ 454.408596] ESR = 0x96000004 [ 454.411638] EC = 0x25: DABT (current EL), IL = 32 bits [ 454.416901] SET = 0, FnV = 0 [ 454.419909] EA = 0, S1PTW = 0 [ 454.423010] FSC = 0x04: level 0 translation fault [ 454.427841] Data abort info: [ 454.430687] ISV = 0, ISS = 0x00000004 [ 454.434484] CM = 0, WnR = 0 [ 454.437404] user pgtable: 4k pages, 48-bit VAs, pgdp=000000000c924000 [ 454.443800] [0000000000000150] pgd=0000000000000000, p4d=0000000000000000 [ 454.450528] Internal error: Oops: 96000004 [#1] PREEMPT SMP [ 454.456036] Modules linked in: [ 454.459053] CPU: 1 PID: 267 Comm: kvm-vcpu-0 Not tainted 5.18.0-rc4 #113 [ 454.465697] Hardware name: Hardkernel ODROID-C4 (DT) [ 454.470612] pstate: 60400009 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) [ 454.477512] pc : kvm_pmu_event_mask.isra.0+0x14/0x74 [ 454.482427] lr : kvm_pmu_set_counter_event_type+0x2c/0x80 [ 454.487775] sp : ffff80000a9839c0 [ 454.491050] x29: ffff80000a9839c0 x28: ffff000000a83a00 x27: 0000000000000000 [ 454.498127] x26: 0000000000000000 x25: 0000000000000000 x24: ffff00000a510000 [ 454.505198] x23: ffff000000a83a00 x22: ffff000003b01000 x21: 0000000000000000 [ 454.512271] x20: 000000000000001f x19: 00000000000003ff x18: 0000000000000000 [ 454.519343] x17: 000000008003fe98 x16: 0000000000000000 x15: 0000000000000000 [ 454.526416] x14: 0000000000000000 x13: 0000000000000000 x12: 0000000000000000 [ 454.533489] x11: 000000008003fdbc x10: 0000000000009d20 x9 : 000000000000001b [ 454.540561] x8 : 0000000000000000 x7 : 0000000000000d00 x6 : 0000000000009d00 [ 454.547633] x5 : 0000000000000037 x4 : 0000000000009d00 x3 : 0d09000000000000 [ 454.554705] x2 : 000000000000001f x1 : 0000000000000000 x0 : 0000000000000000 [ 454.561779] Call trace: [ 454.564191] kvm_pmu_event_mask.isra.0+0x14/0x74 [ 454.568764] kvm_pmu_set_counter_event_type+0x2c/0x80 [ 454.573766] access_pmu_evtyper+0x128/0x170 [ 454.577905] perform_access+0x34/0x80 [ 454.581527] kvm_handle_cp_32+0x13c/0x160 [ 454.585495] kvm_handle_cp15_32+0x1c/0x30 [ 454.589462] handle_exit+0x70/0x180 [ 454.592912] kvm_arch_vcpu_ioctl_run+0x1c4/0x5e0 [ 454.597485] kvm_vcpu_ioctl+0x23c/0x940 [ 454.601280] __arm64_sys_ioctl+0xa8/0xf0 [ 454.605160] invoke_syscall+0x48/0x114 [ 454.608869] el0_svc_common.constprop.0+0xd4/0xfc [ 454.613527] do_el0_svc+0x28/0x90 [ 454.616803] el0_svc+0x34/0xb0 [ 454.619822] el0t_64_sync_handler+0xa4/0x130 [ 454.624049] el0t_64_sync+0x18c/0x190 [ 454.627675] Code: a9be7bfd 910003fd f9000bf3 52807ff3 (b9415001) [ 454.633714] ---[ end trace 0000000000000000 ]--- In this particular case, Linux hasn't detected the presence of a hardware PMU because the PMU node is missing from the DTB, so userspace would have been unable to set the VCPU PMU feature even if it attempted it. What happens is that the 32-bit guest reads ID_DFR0, which advertises the presence of the PMU, and when it tries to program a counter, it triggers the NULL pointer dereference because kvm->arch.arm_pmu is NULL. kvm-arch.arm_pmu was introduced by commit 46b187821472 ("KVM: arm64: Keep a per-VM pointer to the default PMU"). Until that commit, this error would be triggered instead: [ 73.388140] ------------[ cut here ]------------ [ 73.388189] Unknown PMU version 0 [ 73.390420] WARNING: CPU: 1 PID: 264 at arch/arm64/kvm/pmu-emul.c:36 kvm_pmu_event_mask.isra.0+0x6c/0x74 [ 73.399821] Modules linked in: [ 73.402835] CPU: 1 PID: 264 Comm: kvm-vcpu-0 Not tainted 5.17.0 #114 [ 73.409132] Hardware name: Hardkernel ODROID-C4 (DT) [ 73.414048] pstate: 60400009 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) [ 73.420948] pc : kvm_pmu_event_mask.isra.0+0x6c/0x74 [ 73.425863] lr : kvm_pmu_event_mask.isra.0+0x6c/0x74 [ 73.430779] sp : ffff80000a8db9b0 [ 73.434055] x29: ffff80000a8db9b0 x28: ffff000000dbaac0 x27: 0000000000000000 [ 73.441131] x26: ffff000000dbaac0 x25: 00000000c600000d x24: 0000000000180720 [ 73.448203] x23: ffff800009ffbe10 x22: ffff00000b612000 x21: 0000000000000000 [ 73.455276] x20: 000000000000001f x19: 0000000000000000 x18: ffffffffffffffff [ 73.462348] x17: 000000008003fe98 x16: 0000000000000000 x15: 0720072007200720 [ 73.469420] x14: 0720072007200720 x13: ffff800009d32488 x12: 00000000000004e6 [ 73.476493] x11: 00000000000001a2 x10: ffff800009d32488 x9 : ffff800009d32488 [ 73.483565] x8 : 00000000ffffefff x7 : ffff800009d8a488 x6 : ffff800009d8a488 [ 73.490638] x5 : ffff0000f461a9d8 x4 : 0000000000000000 x3 : 0000000000000001 [ 73.497710] x2 : 0000000000000000 x1 : 0000000000000000 x0 : ffff000000dbaac0 [ 73.504784] Call trace: [ 73.507195] kvm_pmu_event_mask.isra.0+0x6c/0x74 [ 73.511768] kvm_pmu_set_counter_event_type+0x2c/0x80 [ 73.516770] access_pmu_evtyper+0x128/0x16c [ 73.520910] perform_access+0x34/0x80 [ 73.524532] kvm_handle_cp_32+0x13c/0x160 [ 73.528500] kvm_handle_cp15_32+0x1c/0x30 [ 73.532467] handle_exit+0x70/0x180 [ 73.535917] kvm_arch_vcpu_ioctl_run+0x20c/0x6e0 [ 73.540489] kvm_vcpu_ioctl+0x2b8/0x9e0 [ 73.544283] __arm64_sys_ioctl+0xa8/0xf0 [ 73.548165] invoke_syscall+0x48/0x114 [ 73.551874] el0_svc_common.constprop.0+0xd4/0xfc [ 73.556531] do_el0_svc+0x28/0x90 [ 73.559808] el0_svc+0x28/0x80 [ 73.562826] el0t_64_sync_handler+0xa4/0x130 [ 73.567054] el0t_64_sync+0x1a0/0x1a4 [ 73.570676] ---[ end trace 0000000000000000 ]--- [ 73.575382] kvm: pmu event creation failed -2 The root cause remains the same: kvm->arch.pmuver was never set to something sensible because the VCPU feature itself was never set. The odroid-c4 is somewhat of a special case, because Linux doesn't probe the PMU. But the above errors can easily be reproduced on any hardware, with or without a PMU driver, as long as userspace doesn't set the PMU feature. Work around the fact that KVM advertises a PMU even when the VCPU feature is not set by gating all PMU emulation on the feature. The guest can still access the registers without KVM injecting an undefined exception. Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20220425145530.723858-1-alexandru.elisei@arm.com
2022-04-25 17:55:30 +03:00
if (!kvm_vcpu_has_pmu(vcpu))
return;
KVM: arm64: PMU: Sanitise PMCR_EL0.LP on first vcpu run Userspace can play some dirty tricks on us by selecting a given PMU version (such as PMUv3p5), restore a PMCR_EL0 value that has PMCR_EL0.LP set, and then switch the PMU version to PMUv3p1, for example. In this situation, we end-up with PMCR_EL0.LP being set and spreading havoc in the PMU emulation. This is specially hard as the first two step can be done on one vcpu and the third step on another, meaning that we need to sanitise *all* vcpus when the PMU version is changed. In orer to avoid a pretty complicated locking situation, defer the sanitisation of PMCR_EL0 to the point where the vcpu is actually run for the first tine, using the existing KVM_REQ_RELOAD_PMU request that calls into kvm_pmu_handle_pmcr(). There is still an obscure corner case where userspace could do the above trick, and then save the VM without running it. They would then observe an inconsistent state (PMUv3.1 + LP set), but that state will be fixed on the first run anyway whenever the guest gets restored on a host. Reported-by: Reiji Watanabe <reijiw@google.com> Signed-off-by: Marc Zyngier <maz@kernel.org>
2022-11-24 13:44:59 +03:00
/* Fixup PMCR_EL0 to reconcile the PMU version and the LP bit */
if (!kvm_pmu_is_3p5(vcpu))
val &= ~ARMV8_PMU_PMCR_LP;
KVM: arm64: PMU: Don't save PMCR_EL0.{C,P} for the vCPU Presently, when a guest writes 1 to PMCR_EL0.{C,P}, which is WO/RAZ, KVM saves the register value, including these bits. When userspace reads the register using KVM_GET_ONE_REG, KVM returns the saved register value as it is (the saved value might have these bits set). This could result in userspace setting these bits on the destination during migration. Consequently, KVM may end up resetting the vPMU counter registers (PMCCNTR_EL0 and/or PMEVCNTR<n>_EL0) to zero on the first KVM_RUN after migration. Fix this by not saving those bits when a guest writes 1 to those bits. Fixes: ab9468340d2b ("arm64: KVM: Add access handler for PMCR register") Cc: stable@vger.kernel.org Reviewed-by: Marc Zyngier <maz@kernel.org> Signed-off-by: Reiji Watanabe <reijiw@google.com> Link: https://lore.kernel.org/r/20230313033234.1475987-1-reijiw@google.com Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
2023-03-13 06:32:34 +03:00
/* The reset bits don't indicate any state, and shouldn't be saved. */
__vcpu_sys_reg(vcpu, PMCR_EL0) = val & ~(ARMV8_PMU_PMCR_C | ARMV8_PMU_PMCR_P);
KVM: arm64: PMU: Sanitise PMCR_EL0.LP on first vcpu run Userspace can play some dirty tricks on us by selecting a given PMU version (such as PMUv3p5), restore a PMCR_EL0 value that has PMCR_EL0.LP set, and then switch the PMU version to PMUv3p1, for example. In this situation, we end-up with PMCR_EL0.LP being set and spreading havoc in the PMU emulation. This is specially hard as the first two step can be done on one vcpu and the third step on another, meaning that we need to sanitise *all* vcpus when the PMU version is changed. In orer to avoid a pretty complicated locking situation, defer the sanitisation of PMCR_EL0 to the point where the vcpu is actually run for the first tine, using the existing KVM_REQ_RELOAD_PMU request that calls into kvm_pmu_handle_pmcr(). There is still an obscure corner case where userspace could do the above trick, and then save the VM without running it. They would then observe an inconsistent state (PMUv3.1 + LP set), but that state will be fixed on the first run anyway whenever the guest gets restored on a host. Reported-by: Reiji Watanabe <reijiw@google.com> Signed-off-by: Marc Zyngier <maz@kernel.org>
2022-11-24 13:44:59 +03:00
arm64: KVM: Add helper to handle PMCR register bits According to ARMv8 spec, when writing 1 to PMCR.E, all counters are enabled by PMCNTENSET, while writing 0 to PMCR.E, all counters are disabled. When writing 1 to PMCR.P, reset all event counters, not including PMCCNTR, to zero. When writing 1 to PMCR.C, reset PMCCNTR to zero. Signed-off-by: Shannon Zhao <shannon.zhao@linaro.org> Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-10-28 07:10:30 +03:00
if (val & ARMV8_PMU_PMCR_E) {
KVM: arm/arm64: Rename kvm_pmu_{enable/disable}_counter functions The kvm_pmu_{enable/disable}_counter functions can enable/disable multiple counters at once as they operate on a bitmask. Let's make this clearer by renaming the function. Suggested-by: Suzuki K Poulose <suzuki.poulose@arm.com> Signed-off-by: Andrew Murray <andrew.murray@arm.com> Reviewed-by: Julien Thierry <julien.thierry@arm.com> Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2019-06-17 22:01:01 +03:00
kvm_pmu_enable_counter_mask(vcpu,
KVM: arm64: Drop unnecessary masking of PMU registers We always sanitise our PMU sysreg on the write side, so there is no need to do it on the read side as well. Drop the unnecessary masking. Acked-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk> Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com> Reviewed-by: Alexandru Elisei <alexandru.elisei@arm.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20210719123902.1493805-3-maz@kernel.org
2021-07-19 15:39:00 +03:00
__vcpu_sys_reg(vcpu, PMCNTENSET_EL0));
arm64: KVM: Add helper to handle PMCR register bits According to ARMv8 spec, when writing 1 to PMCR.E, all counters are enabled by PMCNTENSET, while writing 0 to PMCR.E, all counters are disabled. When writing 1 to PMCR.P, reset all event counters, not including PMCCNTR, to zero. When writing 1 to PMCR.C, reset PMCCNTR to zero. Signed-off-by: Shannon Zhao <shannon.zhao@linaro.org> Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-10-28 07:10:30 +03:00
} else {
KVM: arm64: Disabling disabled PMU counters wastes a lot of time In a KVM guest on arm64, performance counters interrupts have an unnecessary overhead which slows down execution when using the "perf record" command and limits the "perf record" sampling period. The problem is that when a guest VM disables counters by clearing the PMCR_EL0.E bit (bit 0), KVM will disable all counters defined in PMCR_EL0 even if they are not enabled in PMCNTENSET_EL0. KVM disables a counter by calling into the perf framework, in particular by calling perf_event_create_kernel_counter() which is a time consuming operation. So, for example, with a Neoverse N1 CPU core which has 6 event counters and one cycle counter, KVM will always disable all 7 counters even if only one is enabled. This typically happens when using the "perf record" command in a guest VM: perf will disable all event counters with PMCNTENTSET_EL0 and only uses the cycle counter. And when using the "perf record" -F option with a high profiling frequency, the overhead of KVM disabling all counters instead of one on every counter interrupt becomes very noticeable. The problem is fixed by having KVM disable only counters which are enabled in PMCNTENSET_EL0. If a counter is not enabled in PMCNTENSET_EL0 then KVM will not enable it when setting PMCR_EL0.E and it will remain disabled as long as it is not enabled in PMCNTENSET_EL0. So there is effectively no need to disable a counter when clearing PMCR_EL0.E if it is not enabled PMCNTENSET_EL0. Acked-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk> Reviewed-by: Alexandru Elisei <alexandru.elisei@arm.com> Signed-off-by: Alexandre Chartre <alexandre.chartre@oracle.com> [maz: moved 'mask' close to the actual user, simplifying the patch] Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20210712170345.660272-1-alexandre.chartre@oracle.com Link: https://lore.kernel.org/r/20210719123902.1493805-4-maz@kernel.org
2021-07-19 15:39:01 +03:00
kvm_pmu_disable_counter_mask(vcpu,
__vcpu_sys_reg(vcpu, PMCNTENSET_EL0));
arm64: KVM: Add helper to handle PMCR register bits According to ARMv8 spec, when writing 1 to PMCR.E, all counters are enabled by PMCNTENSET, while writing 0 to PMCR.E, all counters are disabled. When writing 1 to PMCR.P, reset all event counters, not including PMCCNTR, to zero. When writing 1 to PMCR.C, reset PMCCNTR to zero. Signed-off-by: Shannon Zhao <shannon.zhao@linaro.org> Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-10-28 07:10:30 +03:00
}
if (val & ARMV8_PMU_PMCR_C)
kvm_pmu_set_counter_value(vcpu, ARMV8_PMU_CYCLE_IDX, 0);
if (val & ARMV8_PMU_PMCR_P) {
KVM: arm64: Disabling disabled PMU counters wastes a lot of time In a KVM guest on arm64, performance counters interrupts have an unnecessary overhead which slows down execution when using the "perf record" command and limits the "perf record" sampling period. The problem is that when a guest VM disables counters by clearing the PMCR_EL0.E bit (bit 0), KVM will disable all counters defined in PMCR_EL0 even if they are not enabled in PMCNTENSET_EL0. KVM disables a counter by calling into the perf framework, in particular by calling perf_event_create_kernel_counter() which is a time consuming operation. So, for example, with a Neoverse N1 CPU core which has 6 event counters and one cycle counter, KVM will always disable all 7 counters even if only one is enabled. This typically happens when using the "perf record" command in a guest VM: perf will disable all event counters with PMCNTENTSET_EL0 and only uses the cycle counter. And when using the "perf record" -F option with a high profiling frequency, the overhead of KVM disabling all counters instead of one on every counter interrupt becomes very noticeable. The problem is fixed by having KVM disable only counters which are enabled in PMCNTENSET_EL0. If a counter is not enabled in PMCNTENSET_EL0 then KVM will not enable it when setting PMCR_EL0.E and it will remain disabled as long as it is not enabled in PMCNTENSET_EL0. So there is effectively no need to disable a counter when clearing PMCR_EL0.E if it is not enabled PMCNTENSET_EL0. Acked-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk> Reviewed-by: Alexandru Elisei <alexandru.elisei@arm.com> Signed-off-by: Alexandre Chartre <alexandre.chartre@oracle.com> [maz: moved 'mask' close to the actual user, simplifying the patch] Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20210712170345.660272-1-alexandre.chartre@oracle.com Link: https://lore.kernel.org/r/20210719123902.1493805-4-maz@kernel.org
2021-07-19 15:39:01 +03:00
unsigned long mask = kvm_pmu_valid_counter_mask(vcpu);
KVM: arm64: Don't zero the cycle count register when PMCR_EL0.P is set According to ARM DDI 0487G.a, page D13-3895, setting the PMCR_EL0.P bit to 1 has the following effect: "Reset all event counters accessible in the current Exception level, not including PMCCNTR_EL0, to zero." Similar behaviour is described for AArch32 on page G8-7022. Make it so. Fixes: c01d6a18023b ("KVM: arm64: pmu: Only handle supported event counters") Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20210618105139.83795-1-alexandru.elisei@arm.com
2021-06-18 13:51:39 +03:00
mask &= ~BIT(ARMV8_PMU_CYCLE_IDX);
KVM: arm64: pmu: Only handle supported event counters Let the code never use unsupported event counters. Change kvm_pmu_handle_pmcr() to only reset supported counters and kvm_pmu_vcpu_reset() to only stop supported counters. Other actions are filtered on the supported counters in kvm/sysregs.c Signed-off-by: Eric Auger <eric.auger@redhat.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20200124142535.29386-5-eric.auger@redhat.com
2020-01-24 17:25:35 +03:00
for_each_set_bit(i, &mask, 32)
KVM: arm64: PMU: Make kvm_pmc the main data structure The PMU code has historically been torn between referencing a counter as a pair vcpu+index or as the PMC pointer. Given that it is pretty easy to go from one representation to the other, standardise on the latter which, IMHO, makes the code slightly more readable. YMMV. Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221113163832.3154370-17-maz@kernel.org
2022-11-13 19:38:32 +03:00
kvm_pmu_set_pmc_value(kvm_vcpu_idx_to_pmc(vcpu, i), 0, true);
arm64: KVM: Add helper to handle PMCR register bits According to ARMv8 spec, when writing 1 to PMCR.E, all counters are enabled by PMCNTENSET, while writing 0 to PMCR.E, all counters are disabled. When writing 1 to PMCR.P, reset all event counters, not including PMCCNTR, to zero. When writing 1 to PMCR.C, reset PMCCNTR to zero. Signed-off-by: Shannon Zhao <shannon.zhao@linaro.org> Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-10-28 07:10:30 +03:00
}
}
KVM: arm64: PMU: Make kvm_pmc the main data structure The PMU code has historically been torn between referencing a counter as a pair vcpu+index or as the PMC pointer. Given that it is pretty easy to go from one representation to the other, standardise on the latter which, IMHO, makes the code slightly more readable. YMMV. Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221113163832.3154370-17-maz@kernel.org
2022-11-13 19:38:32 +03:00
static bool kvm_pmu_counter_is_enabled(struct kvm_pmc *pmc)
arm64: KVM: PMU: Add perf event map and introduce perf event creating function When we use tools like perf on host, perf passes the event type and the id of this event type category to kernel, then kernel will map them to hardware event number and write this number to PMU PMEVTYPER<n>_EL0 register. When getting the event number in KVM, directly use raw event type to create a perf_event for it. Signed-off-by: Shannon Zhao <shannon.zhao@linaro.org> Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-07-03 09:27:25 +03:00
{
KVM: arm64: PMU: Make kvm_pmc the main data structure The PMU code has historically been torn between referencing a counter as a pair vcpu+index or as the PMC pointer. Given that it is pretty easy to go from one representation to the other, standardise on the latter which, IMHO, makes the code slightly more readable. YMMV. Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221113163832.3154370-17-maz@kernel.org
2022-11-13 19:38:32 +03:00
struct kvm_vcpu *vcpu = kvm_pmc_to_vcpu(pmc);
KVM: arm64: Rewrite system register accessors to read/write functions Currently we access the system registers array via the vcpu_sys_reg() macro. However, we are about to change the behavior to some times modify the register file directly, so let's change this to two primitives: * Accessor macros vcpu_write_sys_reg() and vcpu_read_sys_reg() * Direct array access macro __vcpu_sys_reg() The accessor macros should be used in places where the code needs to access the currently loaded VCPU's state as observed by the guest. For example, when trapping on cache related registers, a write to a system register should go directly to the VCPU version of the register. The direct array access macro can be used in places where the VCPU is known to never be running (for example userspace access) or for registers which are never context switched (for example all the PMU system registers). This rewrites all users of vcpu_sys_regs to one of the macros described above. No functional change. Acked-by: Marc Zyngier <marc.zyngier@arm.com> Reviewed-by: Andrew Jones <drjones@redhat.com> Signed-off-by: Christoffer Dall <cdall@cs.columbia.edu> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2016-03-16 17:38:53 +03:00
return (__vcpu_sys_reg(vcpu, PMCR_EL0) & ARMV8_PMU_PMCR_E) &&
KVM: arm64: PMU: Make kvm_pmc the main data structure The PMU code has historically been torn between referencing a counter as a pair vcpu+index or as the PMC pointer. Given that it is pretty easy to go from one representation to the other, standardise on the latter which, IMHO, makes the code slightly more readable. YMMV. Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221113163832.3154370-17-maz@kernel.org
2022-11-13 19:38:32 +03:00
(__vcpu_sys_reg(vcpu, PMCNTENSET_EL0) & BIT(pmc->idx));
arm64: KVM: PMU: Add perf event map and introduce perf event creating function When we use tools like perf on host, perf passes the event type and the id of this event type category to kernel, then kernel will map them to hardware event number and write this number to PMU PMEVTYPER<n>_EL0 register. When getting the event number in KVM, directly use raw event type to create a perf_event for it. Signed-off-by: Shannon Zhao <shannon.zhao@linaro.org> Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-07-03 09:27:25 +03:00
}
/**
KVM: arm/arm64: Re-create event when setting counter value The perf event sample_period is currently set based upon the current counter value, when PMXEVTYPER is written to and the perf event is created. However the user may choose to write the type before the counter value in which case sample_period will be set incorrectly. Let's instead decouple event creation from PMXEVTYPER and (re)create the event in either suitation. Signed-off-by: Andrew Murray <andrew.murray@arm.com> Reviewed-by: Julien Thierry <julien.thierry@arm.com> Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2019-06-17 22:01:03 +03:00
* kvm_pmu_create_perf_event - create a perf event for a counter
KVM: arm64: PMU: Make kvm_pmc the main data structure The PMU code has historically been torn between referencing a counter as a pair vcpu+index or as the PMC pointer. Given that it is pretty easy to go from one representation to the other, standardise on the latter which, IMHO, makes the code slightly more readable. YMMV. Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221113163832.3154370-17-maz@kernel.org
2022-11-13 19:38:32 +03:00
* @pmc: Counter context
arm64: KVM: PMU: Add perf event map and introduce perf event creating function When we use tools like perf on host, perf passes the event type and the id of this event type category to kernel, then kernel will map them to hardware event number and write this number to PMU PMEVTYPER<n>_EL0 register. When getting the event number in KVM, directly use raw event type to create a perf_event for it. Signed-off-by: Shannon Zhao <shannon.zhao@linaro.org> Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-07-03 09:27:25 +03:00
*/
KVM: arm64: PMU: Make kvm_pmc the main data structure The PMU code has historically been torn between referencing a counter as a pair vcpu+index or as the PMC pointer. Given that it is pretty easy to go from one representation to the other, standardise on the latter which, IMHO, makes the code slightly more readable. YMMV. Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221113163832.3154370-17-maz@kernel.org
2022-11-13 19:38:32 +03:00
static void kvm_pmu_create_perf_event(struct kvm_pmc *pmc)
arm64: KVM: PMU: Add perf event map and introduce perf event creating function When we use tools like perf on host, perf passes the event type and the id of this event type category to kernel, then kernel will map them to hardware event number and write this number to PMU PMEVTYPER<n>_EL0 register. When getting the event number in KVM, directly use raw event type to create a perf_event for it. Signed-off-by: Shannon Zhao <shannon.zhao@linaro.org> Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-07-03 09:27:25 +03:00
{
KVM: arm64: PMU: Make kvm_pmc the main data structure The PMU code has historically been torn between referencing a counter as a pair vcpu+index or as the PMC pointer. Given that it is pretty easy to go from one representation to the other, standardise on the latter which, IMHO, makes the code slightly more readable. YMMV. Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221113163832.3154370-17-maz@kernel.org
2022-11-13 19:38:32 +03:00
struct kvm_vcpu *vcpu = kvm_pmc_to_vcpu(pmc);
KVM: arm64: Keep a per-VM pointer to the default PMU As we are about to allow selection of the PMU exposed to a guest, start by keeping track of the default one instead of only the PMU version. Signed-off-by: Marc Zyngier <maz@kernel.org> Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com> Link: https://lore.kernel.org/r/20220127161759.53553-4-alexandru.elisei@arm.com
2022-01-27 19:17:56 +03:00
struct arm_pmu *arm_pmu = vcpu->kvm->arch.arm_pmu;
arm64: KVM: PMU: Add perf event map and introduce perf event creating function When we use tools like perf on host, perf passes the event type and the id of this event type category to kernel, then kernel will map them to hardware event number and write this number to PMU PMEVTYPER<n>_EL0 register. When getting the event number in KVM, directly use raw event type to create a perf_event for it. Signed-off-by: Shannon Zhao <shannon.zhao@linaro.org> Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-07-03 09:27:25 +03:00
struct perf_event *event;
struct perf_event_attr attr;
KVM: arm64: PMU: Make kvm_pmc the main data structure The PMU code has historically been torn between referencing a counter as a pair vcpu+index or as the PMC pointer. Given that it is pretty easy to go from one representation to the other, standardise on the latter which, IMHO, makes the code slightly more readable. YMMV. Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221113163832.3154370-17-maz@kernel.org
2022-11-13 19:38:32 +03:00
u64 eventsel, reg, data;
KVM: arm/arm64: Re-create event when setting counter value The perf event sample_period is currently set based upon the current counter value, when PMXEVTYPER is written to and the perf event is created. However the user may choose to write the type before the counter value in which case sample_period will be set incorrectly. Let's instead decouple event creation from PMXEVTYPER and (re)create the event in either suitation. Signed-off-by: Andrew Murray <andrew.murray@arm.com> Reviewed-by: Julien Thierry <julien.thierry@arm.com> Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2019-06-17 22:01:03 +03:00
KVM: arm64: PMU: Make kvm_pmc the main data structure The PMU code has historically been torn between referencing a counter as a pair vcpu+index or as the PMC pointer. Given that it is pretty easy to go from one representation to the other, standardise on the latter which, IMHO, makes the code slightly more readable. YMMV. Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221113163832.3154370-17-maz@kernel.org
2022-11-13 19:38:32 +03:00
reg = counter_index_to_evtreg(pmc->idx);
KVM: arm/arm64: Re-create event when setting counter value The perf event sample_period is currently set based upon the current counter value, when PMXEVTYPER is written to and the perf event is created. However the user may choose to write the type before the counter value in which case sample_period will be set incorrectly. Let's instead decouple event creation from PMXEVTYPER and (re)create the event in either suitation. Signed-off-by: Andrew Murray <andrew.murray@arm.com> Reviewed-by: Julien Thierry <julien.thierry@arm.com> Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2019-06-17 22:01:03 +03:00
data = __vcpu_sys_reg(vcpu, reg);
arm64: KVM: PMU: Add perf event map and introduce perf event creating function When we use tools like perf on host, perf passes the event type and the id of this event type category to kernel, then kernel will map them to hardware event number and write this number to PMU PMEVTYPER<n>_EL0 register. When getting the event number in KVM, directly use raw event type to create a perf_event for it. Signed-off-by: Shannon Zhao <shannon.zhao@linaro.org> Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-07-03 09:27:25 +03:00
KVM: arm64: PMU: Make kvm_pmc the main data structure The PMU code has historically been torn between referencing a counter as a pair vcpu+index or as the PMC pointer. Given that it is pretty easy to go from one representation to the other, standardise on the latter which, IMHO, makes the code slightly more readable. YMMV. Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221113163832.3154370-17-maz@kernel.org
2022-11-13 19:38:32 +03:00
kvm_pmu_stop_counter(pmc);
KVM: arm64: Add PMU event filtering infrastructure It can be desirable to expose a PMU to a guest, and yet not want the guest to be able to count some of the implemented events (because this would give information on shared resources, for example. For this, let's extend the PMUv3 device API, and offer a way to setup a bitmap of the allowed events (the default being no bitmap, and thus no filtering). Userspace can thus allow/deny ranges of event. The default policy depends on the "polarity" of the first filter setup (default deny if the filter allows events, and default allow if the filter denies events). This allows to setup exactly what is allowed for a given guest. Note that although the ioctl is per-vcpu, the map of allowed events is global to the VM (it can be setup from any vcpu until the vcpu PMU is initialized). Reviewed-by: Andrew Jones <drjones@redhat.com> Signed-off-by: Marc Zyngier <maz@kernel.org>
2020-02-12 14:31:02 +03:00
if (pmc->idx == ARMV8_PMU_CYCLE_IDX)
eventsel = ARMV8_PMUV3_PERFCTR_CPU_CYCLES;
else
eventsel = data & kvm_pmu_event_mask(vcpu->kvm);
KVM: arm64: PMU: Align chained counter implementation with architecture pseudocode Ricardo recently pointed out that the PMU chained counter emulation in KVM wasn't quite behaving like the one on actual hardware, in the sense that a chained counter would expose an overflow on both halves of a chained counter, while KVM would only expose the overflow on the top half. The difference is subtle, but significant. What does the architecture say (DDI0087 H.a): - Up to PMUv3p4, all counters but the cycle counter are 32bit - A 32bit counter that overflows generates a CHAIN event on the adjacent counter after exposing its own overflow status - The CHAIN event is accounted if the counter is correctly configured (CHAIN event selected and counter enabled) This all means that our current implementation (which uses 64bit perf events) prevents us from emulating this overflow on the lower half. How to fix this? By implementing the above, to the letter. This largely results in code deletion, removing the notions of "counter pair", "chained counters", and "canonical counter". The code is further restructured to make the CHAIN handling similar to SWINC, as the two are now extremely similar in behaviour. Reported-by: Ricardo Koller <ricarkol@google.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Reviewed-by: Reiji Watanabe <reijiw@google.com> Link: https://lore.kernel.org/r/20221113163832.3154370-3-maz@kernel.org
2022-11-13 19:38:18 +03:00
/*
* Neither SW increment nor chained events need to be backed
* by a perf event.
*/
if (eventsel == ARMV8_PMUV3_PERFCTR_SW_INCR ||
eventsel == ARMV8_PMUV3_PERFCTR_CHAIN)
KVM: arm64: Add PMU event filtering infrastructure It can be desirable to expose a PMU to a guest, and yet not want the guest to be able to count some of the implemented events (because this would give information on shared resources, for example. For this, let's extend the PMUv3 device API, and offer a way to setup a bitmap of the allowed events (the default being no bitmap, and thus no filtering). Userspace can thus allow/deny ranges of event. The default policy depends on the "polarity" of the first filter setup (default deny if the filter allows events, and default allow if the filter denies events). This allows to setup exactly what is allowed for a given guest. Note that although the ioctl is per-vcpu, the map of allowed events is global to the VM (it can be setup from any vcpu until the vcpu PMU is initialized). Reviewed-by: Andrew Jones <drjones@redhat.com> Signed-off-by: Marc Zyngier <maz@kernel.org>
2020-02-12 14:31:02 +03:00
return;
arm64: KVM: PMU: Add perf event map and introduce perf event creating function When we use tools like perf on host, perf passes the event type and the id of this event type category to kernel, then kernel will map them to hardware event number and write this number to PMU PMEVTYPER<n>_EL0 register. When getting the event number in KVM, directly use raw event type to create a perf_event for it. Signed-off-by: Shannon Zhao <shannon.zhao@linaro.org> Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-07-03 09:27:25 +03:00
KVM: arm64: Add PMU event filtering infrastructure It can be desirable to expose a PMU to a guest, and yet not want the guest to be able to count some of the implemented events (because this would give information on shared resources, for example. For this, let's extend the PMUv3 device API, and offer a way to setup a bitmap of the allowed events (the default being no bitmap, and thus no filtering). Userspace can thus allow/deny ranges of event. The default policy depends on the "polarity" of the first filter setup (default deny if the filter allows events, and default allow if the filter denies events). This allows to setup exactly what is allowed for a given guest. Note that although the ioctl is per-vcpu, the map of allowed events is global to the VM (it can be setup from any vcpu until the vcpu PMU is initialized). Reviewed-by: Andrew Jones <drjones@redhat.com> Signed-off-by: Marc Zyngier <maz@kernel.org>
2020-02-12 14:31:02 +03:00
/*
* If we have a filter in place and that the event isn't allowed, do
* not install a perf event either.
*/
if (vcpu->kvm->arch.pmu_filter &&
!test_bit(eventsel, vcpu->kvm->arch.pmu_filter))
arm64: KVM: Add access handler for PMSWINC register Add access handler which emulates writing and reading PMSWINC register and add support for creating software increment event. Signed-off-by: Shannon Zhao <shannon.zhao@linaro.org> Reviewed-by: Andrew Jones <drjones@redhat.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-09-08 10:49:39 +03:00
return;
arm64: KVM: PMU: Add perf event map and introduce perf event creating function When we use tools like perf on host, perf passes the event type and the id of this event type category to kernel, then kernel will map them to hardware event number and write this number to PMU PMEVTYPER<n>_EL0 register. When getting the event number in KVM, directly use raw event type to create a perf_event for it. Signed-off-by: Shannon Zhao <shannon.zhao@linaro.org> Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-07-03 09:27:25 +03:00
memset(&attr, 0, sizeof(struct perf_event_attr));
KVM: arm64: Keep a per-VM pointer to the default PMU As we are about to allow selection of the PMU exposed to a guest, start by keeping track of the default one instead of only the PMU version. Signed-off-by: Marc Zyngier <maz@kernel.org> Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com> Link: https://lore.kernel.org/r/20220127161759.53553-4-alexandru.elisei@arm.com
2022-01-27 19:17:56 +03:00
attr.type = arm_pmu->pmu.type;
arm64: KVM: PMU: Add perf event map and introduce perf event creating function When we use tools like perf on host, perf passes the event type and the id of this event type category to kernel, then kernel will map them to hardware event number and write this number to PMU PMEVTYPER<n>_EL0 register. When getting the event number in KVM, directly use raw event type to create a perf_event for it. Signed-off-by: Shannon Zhao <shannon.zhao@linaro.org> Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-07-03 09:27:25 +03:00
attr.size = sizeof(attr);
attr.pinned = 1;
KVM: arm64: PMU: Make kvm_pmc the main data structure The PMU code has historically been torn between referencing a counter as a pair vcpu+index or as the PMC pointer. Given that it is pretty easy to go from one representation to the other, standardise on the latter which, IMHO, makes the code slightly more readable. YMMV. Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221113163832.3154370-17-maz@kernel.org
2022-11-13 19:38:32 +03:00
attr.disabled = !kvm_pmu_counter_is_enabled(pmc);
arm64: KVM: PMU: Add perf event map and introduce perf event creating function When we use tools like perf on host, perf passes the event type and the id of this event type category to kernel, then kernel will map them to hardware event number and write this number to PMU PMEVTYPER<n>_EL0 register. When getting the event number in KVM, directly use raw event type to create a perf_event for it. Signed-off-by: Shannon Zhao <shannon.zhao@linaro.org> Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-07-03 09:27:25 +03:00
attr.exclude_user = data & ARMV8_PMU_EXCLUDE_EL0 ? 1 : 0;
attr.exclude_kernel = data & ARMV8_PMU_EXCLUDE_EL1 ? 1 : 0;
attr.exclude_hv = 1; /* Don't count EL2 events */
attr.exclude_host = 1; /* Don't count host events */
KVM: arm64: Add PMU event filtering infrastructure It can be desirable to expose a PMU to a guest, and yet not want the guest to be able to count some of the implemented events (because this would give information on shared resources, for example. For this, let's extend the PMUv3 device API, and offer a way to setup a bitmap of the allowed events (the default being no bitmap, and thus no filtering). Userspace can thus allow/deny ranges of event. The default policy depends on the "polarity" of the first filter setup (default deny if the filter allows events, and default allow if the filter denies events). This allows to setup exactly what is allowed for a given guest. Note that although the ioctl is per-vcpu, the map of allowed events is global to the VM (it can be setup from any vcpu until the vcpu PMU is initialized). Reviewed-by: Andrew Jones <drjones@redhat.com> Signed-off-by: Marc Zyngier <maz@kernel.org>
2020-02-12 14:31:02 +03:00
attr.config = eventsel;
arm64: KVM: PMU: Add perf event map and introduce perf event creating function When we use tools like perf on host, perf passes the event type and the id of this event type category to kernel, then kernel will map them to hardware event number and write this number to PMU PMEVTYPER<n>_EL0 register. When getting the event number in KVM, directly use raw event type to create a perf_event for it. Signed-off-by: Shannon Zhao <shannon.zhao@linaro.org> Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-07-03 09:27:25 +03:00
KVM: arm64: PMU: Align chained counter implementation with architecture pseudocode Ricardo recently pointed out that the PMU chained counter emulation in KVM wasn't quite behaving like the one on actual hardware, in the sense that a chained counter would expose an overflow on both halves of a chained counter, while KVM would only expose the overflow on the top half. The difference is subtle, but significant. What does the architecture say (DDI0087 H.a): - Up to PMUv3p4, all counters but the cycle counter are 32bit - A 32bit counter that overflows generates a CHAIN event on the adjacent counter after exposing its own overflow status - The CHAIN event is accounted if the counter is correctly configured (CHAIN event selected and counter enabled) This all means that our current implementation (which uses 64bit perf events) prevents us from emulating this overflow on the lower half. How to fix this? By implementing the above, to the letter. This largely results in code deletion, removing the notions of "counter pair", "chained counters", and "canonical counter". The code is further restructured to make the CHAIN handling similar to SWINC, as the two are now extremely similar in behaviour. Reported-by: Ricardo Koller <ricarkol@google.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Reviewed-by: Reiji Watanabe <reijiw@google.com> Link: https://lore.kernel.org/r/20221113163832.3154370-3-maz@kernel.org
2022-11-13 19:38:18 +03:00
/*
* If counting with a 64bit counter, advertise it to the perf
KVM: arm64: PMU: Distinguish between 64bit counter and 64bit overflow The PMU architecture makes a subtle difference between a 64bit counter and a counter that has a 64bit overflow. This is for example the case of the cycle counter, which can generate an overflow on a 32bit boundary if PMCR_EL0.LC==0 despite the accumulation being done on 64 bits. Use this distinction in the few cases where it matters in the code, as we will reuse this with PMUv3p5 long counters. Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221113163832.3154370-5-maz@kernel.org
2022-11-13 19:38:20 +03:00
* code, carefully dealing with the initial sample period
* which also depends on the overflow.
KVM: arm64: PMU: Align chained counter implementation with architecture pseudocode Ricardo recently pointed out that the PMU chained counter emulation in KVM wasn't quite behaving like the one on actual hardware, in the sense that a chained counter would expose an overflow on both halves of a chained counter, while KVM would only expose the overflow on the top half. The difference is subtle, but significant. What does the architecture say (DDI0087 H.a): - Up to PMUv3p4, all counters but the cycle counter are 32bit - A 32bit counter that overflows generates a CHAIN event on the adjacent counter after exposing its own overflow status - The CHAIN event is accounted if the counter is correctly configured (CHAIN event selected and counter enabled) This all means that our current implementation (which uses 64bit perf events) prevents us from emulating this overflow on the lower half. How to fix this? By implementing the above, to the letter. This largely results in code deletion, removing the notions of "counter pair", "chained counters", and "canonical counter". The code is further restructured to make the CHAIN handling similar to SWINC, as the two are now extremely similar in behaviour. Reported-by: Ricardo Koller <ricarkol@google.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Reviewed-by: Reiji Watanabe <reijiw@google.com> Link: https://lore.kernel.org/r/20221113163832.3154370-3-maz@kernel.org
2022-11-13 19:38:18 +03:00
*/
KVM: arm64: PMU: Make kvm_pmc the main data structure The PMU code has historically been torn between referencing a counter as a pair vcpu+index or as the PMC pointer. Given that it is pretty easy to go from one representation to the other, standardise on the latter which, IMHO, makes the code slightly more readable. YMMV. Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221113163832.3154370-17-maz@kernel.org
2022-11-13 19:38:32 +03:00
if (kvm_pmc_is_64bit(pmc))
KVM: arm64: PMU: Align chained counter implementation with architecture pseudocode Ricardo recently pointed out that the PMU chained counter emulation in KVM wasn't quite behaving like the one on actual hardware, in the sense that a chained counter would expose an overflow on both halves of a chained counter, while KVM would only expose the overflow on the top half. The difference is subtle, but significant. What does the architecture say (DDI0087 H.a): - Up to PMUv3p4, all counters but the cycle counter are 32bit - A 32bit counter that overflows generates a CHAIN event on the adjacent counter after exposing its own overflow status - The CHAIN event is accounted if the counter is correctly configured (CHAIN event selected and counter enabled) This all means that our current implementation (which uses 64bit perf events) prevents us from emulating this overflow on the lower half. How to fix this? By implementing the above, to the letter. This largely results in code deletion, removing the notions of "counter pair", "chained counters", and "canonical counter". The code is further restructured to make the CHAIN handling similar to SWINC, as the two are now extremely similar in behaviour. Reported-by: Ricardo Koller <ricarkol@google.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Reviewed-by: Reiji Watanabe <reijiw@google.com> Link: https://lore.kernel.org/r/20221113163832.3154370-3-maz@kernel.org
2022-11-13 19:38:18 +03:00
attr.config1 |= PERF_ATTR_CFG1_COUNTER_64BIT;
KVM: arm64: PMU: Distinguish between 64bit counter and 64bit overflow The PMU architecture makes a subtle difference between a 64bit counter and a counter that has a 64bit overflow. This is for example the case of the cycle counter, which can generate an overflow on a 32bit boundary if PMCR_EL0.LC==0 despite the accumulation being done on 64 bits. Use this distinction in the few cases where it matters in the code, as we will reuse this with PMUv3p5 long counters. Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221113163832.3154370-5-maz@kernel.org
2022-11-13 19:38:20 +03:00
KVM: arm64: PMU: Make kvm_pmc the main data structure The PMU code has historically been torn between referencing a counter as a pair vcpu+index or as the PMC pointer. Given that it is pretty easy to go from one representation to the other, standardise on the latter which, IMHO, makes the code slightly more readable. YMMV. Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221113163832.3154370-17-maz@kernel.org
2022-11-13 19:38:32 +03:00
attr.sample_period = compute_period(pmc, kvm_pmu_get_pmc_value(pmc));
arm64: KVM: PMU: Add perf event map and introduce perf event creating function When we use tools like perf on host, perf passes the event type and the id of this event type category to kernel, then kernel will map them to hardware event number and write this number to PMU PMEVTYPER<n>_EL0 register. When getting the event number in KVM, directly use raw event type to create a perf_event for it. Signed-off-by: Shannon Zhao <shannon.zhao@linaro.org> Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-07-03 09:27:25 +03:00
KVM: arm64: PMU: Align chained counter implementation with architecture pseudocode Ricardo recently pointed out that the PMU chained counter emulation in KVM wasn't quite behaving like the one on actual hardware, in the sense that a chained counter would expose an overflow on both halves of a chained counter, while KVM would only expose the overflow on the top half. The difference is subtle, but significant. What does the architecture say (DDI0087 H.a): - Up to PMUv3p4, all counters but the cycle counter are 32bit - A 32bit counter that overflows generates a CHAIN event on the adjacent counter after exposing its own overflow status - The CHAIN event is accounted if the counter is correctly configured (CHAIN event selected and counter enabled) This all means that our current implementation (which uses 64bit perf events) prevents us from emulating this overflow on the lower half. How to fix this? By implementing the above, to the letter. This largely results in code deletion, removing the notions of "counter pair", "chained counters", and "canonical counter". The code is further restructured to make the CHAIN handling similar to SWINC, as the two are now extremely similar in behaviour. Reported-by: Ricardo Koller <ricarkol@google.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Reviewed-by: Reiji Watanabe <reijiw@google.com> Link: https://lore.kernel.org/r/20221113163832.3154370-3-maz@kernel.org
2022-11-13 19:38:18 +03:00
event = perf_event_create_kernel_counter(&attr, -1, current,
arm64: KVM: Add PMU overflow interrupt routing When calling perf_event_create_kernel_counter to create perf_event, assign a overflow handler. Then when the perf event overflows, set the corresponding bit of guest PMOVSSET register. If this counter is enabled and its interrupt is enabled as well, kick the vcpu to sync the interrupt. On VM entry, if there is counter overflowed and interrupt level is changed, inject the interrupt with corresponding level. On VM exit, sync the interrupt level as well if it has been changed. Signed-off-by: Shannon Zhao <shannon.zhao@linaro.org> Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> Reviewed-by: Andrew Jones <drjones@redhat.com> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2016-02-26 14:29:19 +03:00
kvm_pmu_perf_overflow, pmc);
KVM: arm/arm64: Support chained PMU counters ARMv8 provides support for chained PMU counters, where an event type of 0x001E is set for odd-numbered counters, the event counter will increment by one for each overflow of the preceding even-numbered counter. Let's emulate this in KVM by creating a 64 bit perf counter when a user chains two emulated counters together. For chained events we only support generating an overflow interrupt on the high counter. We use the attributes of the low counter to determine the attributes of the perf event. Suggested-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Andrew Murray <andrew.murray@arm.com> Reviewed-by: Julien Thierry <julien.thierry@arm.com> Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2019-06-17 22:01:05 +03:00
arm64: KVM: PMU: Add perf event map and introduce perf event creating function When we use tools like perf on host, perf passes the event type and the id of this event type category to kernel, then kernel will map them to hardware event number and write this number to PMU PMEVTYPER<n>_EL0 register. When getting the event number in KVM, directly use raw event type to create a perf_event for it. Signed-off-by: Shannon Zhao <shannon.zhao@linaro.org> Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-07-03 09:27:25 +03:00
if (IS_ERR(event)) {
pr_err_once("kvm: pmu event creation failed %ld\n",
PTR_ERR(event));
return;
}
pmc->perf_event = event;
}
arm64: KVM: Add a new feature bit for PMUv3 To support guest PMUv3, use one bit of the VCPU INIT feature array. Initialize the PMU when initialzing the vcpu with that bit and PMU overflow interrupt set. Signed-off-by: Shannon Zhao <shannon.zhao@linaro.org> Acked-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Andrew Jones <drjones@redhat.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2016-01-11 17:46:15 +03:00
KVM: arm/arm64: Re-create event when setting counter value The perf event sample_period is currently set based upon the current counter value, when PMXEVTYPER is written to and the perf event is created. However the user may choose to write the type before the counter value in which case sample_period will be set incorrectly. Let's instead decouple event creation from PMXEVTYPER and (re)create the event in either suitation. Signed-off-by: Andrew Murray <andrew.murray@arm.com> Reviewed-by: Julien Thierry <julien.thierry@arm.com> Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2019-06-17 22:01:03 +03:00
/**
* kvm_pmu_set_counter_event_type - set selected counter to monitor some event
* @vcpu: The vcpu pointer
* @data: The data guest writes to PMXEVTYPER_EL0
* @select_idx: The number of selected counter
*
* When OS accesses PMXEVTYPER_EL0, that means it wants to set a PMC to count an
* event with given hardware event number. Here we call perf_event API to
* emulate this action and create a kernel perf event for it.
*/
void kvm_pmu_set_counter_event_type(struct kvm_vcpu *vcpu, u64 data,
u64 select_idx)
{
KVM: arm64: PMU: Make kvm_pmc the main data structure The PMU code has historically been torn between referencing a counter as a pair vcpu+index or as the PMC pointer. Given that it is pretty easy to go from one representation to the other, standardise on the latter which, IMHO, makes the code slightly more readable. YMMV. Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221113163832.3154370-17-maz@kernel.org
2022-11-13 19:38:32 +03:00
struct kvm_pmc *pmc = kvm_vcpu_idx_to_pmc(vcpu, select_idx);
KVM: arm64: Use event mask matching architecture revision The PMU code suffers from a small defect where we assume that the event number provided by the guest is always 16 bit wide, even if the CPU only implements the ARMv8.0 architecture. This isn't really problematic in the sense that the event number ends up in a system register, cropping it to the right width, but still this needs fixing. In order to make it work, let's probe the version of the PMU that the guest is going to use. This is done by temporarily creating a kernel event and looking at the PMUVer field that has been saved at probe time in the associated arm_pmu structure. This in turn gets saved in the kvm structure, and subsequently used to compute the event mask that gets used throughout the PMU code. Signed-off-by: Marc Zyngier <maz@kernel.org>
2020-03-17 14:11:56 +03:00
u64 reg, mask;
KVM/arm64: Don't emulate a PMU for 32-bit guests if feature not set kvm->arch.arm_pmu is set when userspace attempts to set the first PMU attribute. As certain attributes are mandatory, arm_pmu ends up always being set to a valid arm_pmu, otherwise KVM will refuse to run the VCPU. However, this only happens if the VCPU has the PMU feature. If the VCPU doesn't have the feature bit set, kvm->arch.arm_pmu will be left uninitialized and equal to NULL. KVM doesn't do ID register emulation for 32-bit guests and accesses to the PMU registers aren't gated by the pmu_visibility() function. This is done to prevent injecting unexpected undefined exceptions in guests which have detected the presence of a hardware PMU. But even though the VCPU feature is missing, KVM still attempts to emulate certain aspects of the PMU when PMU registers are accessed. This leads to a NULL pointer dereference like this one, which happens on an odroid-c4 board when running the kvm-unit-tests pmu-cycle-counter test with kvmtool and without the PMU feature being set: [ 454.402699] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000150 [ 454.405865] Mem abort info: [ 454.408596] ESR = 0x96000004 [ 454.411638] EC = 0x25: DABT (current EL), IL = 32 bits [ 454.416901] SET = 0, FnV = 0 [ 454.419909] EA = 0, S1PTW = 0 [ 454.423010] FSC = 0x04: level 0 translation fault [ 454.427841] Data abort info: [ 454.430687] ISV = 0, ISS = 0x00000004 [ 454.434484] CM = 0, WnR = 0 [ 454.437404] user pgtable: 4k pages, 48-bit VAs, pgdp=000000000c924000 [ 454.443800] [0000000000000150] pgd=0000000000000000, p4d=0000000000000000 [ 454.450528] Internal error: Oops: 96000004 [#1] PREEMPT SMP [ 454.456036] Modules linked in: [ 454.459053] CPU: 1 PID: 267 Comm: kvm-vcpu-0 Not tainted 5.18.0-rc4 #113 [ 454.465697] Hardware name: Hardkernel ODROID-C4 (DT) [ 454.470612] pstate: 60400009 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) [ 454.477512] pc : kvm_pmu_event_mask.isra.0+0x14/0x74 [ 454.482427] lr : kvm_pmu_set_counter_event_type+0x2c/0x80 [ 454.487775] sp : ffff80000a9839c0 [ 454.491050] x29: ffff80000a9839c0 x28: ffff000000a83a00 x27: 0000000000000000 [ 454.498127] x26: 0000000000000000 x25: 0000000000000000 x24: ffff00000a510000 [ 454.505198] x23: ffff000000a83a00 x22: ffff000003b01000 x21: 0000000000000000 [ 454.512271] x20: 000000000000001f x19: 00000000000003ff x18: 0000000000000000 [ 454.519343] x17: 000000008003fe98 x16: 0000000000000000 x15: 0000000000000000 [ 454.526416] x14: 0000000000000000 x13: 0000000000000000 x12: 0000000000000000 [ 454.533489] x11: 000000008003fdbc x10: 0000000000009d20 x9 : 000000000000001b [ 454.540561] x8 : 0000000000000000 x7 : 0000000000000d00 x6 : 0000000000009d00 [ 454.547633] x5 : 0000000000000037 x4 : 0000000000009d00 x3 : 0d09000000000000 [ 454.554705] x2 : 000000000000001f x1 : 0000000000000000 x0 : 0000000000000000 [ 454.561779] Call trace: [ 454.564191] kvm_pmu_event_mask.isra.0+0x14/0x74 [ 454.568764] kvm_pmu_set_counter_event_type+0x2c/0x80 [ 454.573766] access_pmu_evtyper+0x128/0x170 [ 454.577905] perform_access+0x34/0x80 [ 454.581527] kvm_handle_cp_32+0x13c/0x160 [ 454.585495] kvm_handle_cp15_32+0x1c/0x30 [ 454.589462] handle_exit+0x70/0x180 [ 454.592912] kvm_arch_vcpu_ioctl_run+0x1c4/0x5e0 [ 454.597485] kvm_vcpu_ioctl+0x23c/0x940 [ 454.601280] __arm64_sys_ioctl+0xa8/0xf0 [ 454.605160] invoke_syscall+0x48/0x114 [ 454.608869] el0_svc_common.constprop.0+0xd4/0xfc [ 454.613527] do_el0_svc+0x28/0x90 [ 454.616803] el0_svc+0x34/0xb0 [ 454.619822] el0t_64_sync_handler+0xa4/0x130 [ 454.624049] el0t_64_sync+0x18c/0x190 [ 454.627675] Code: a9be7bfd 910003fd f9000bf3 52807ff3 (b9415001) [ 454.633714] ---[ end trace 0000000000000000 ]--- In this particular case, Linux hasn't detected the presence of a hardware PMU because the PMU node is missing from the DTB, so userspace would have been unable to set the VCPU PMU feature even if it attempted it. What happens is that the 32-bit guest reads ID_DFR0, which advertises the presence of the PMU, and when it tries to program a counter, it triggers the NULL pointer dereference because kvm->arch.arm_pmu is NULL. kvm-arch.arm_pmu was introduced by commit 46b187821472 ("KVM: arm64: Keep a per-VM pointer to the default PMU"). Until that commit, this error would be triggered instead: [ 73.388140] ------------[ cut here ]------------ [ 73.388189] Unknown PMU version 0 [ 73.390420] WARNING: CPU: 1 PID: 264 at arch/arm64/kvm/pmu-emul.c:36 kvm_pmu_event_mask.isra.0+0x6c/0x74 [ 73.399821] Modules linked in: [ 73.402835] CPU: 1 PID: 264 Comm: kvm-vcpu-0 Not tainted 5.17.0 #114 [ 73.409132] Hardware name: Hardkernel ODROID-C4 (DT) [ 73.414048] pstate: 60400009 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) [ 73.420948] pc : kvm_pmu_event_mask.isra.0+0x6c/0x74 [ 73.425863] lr : kvm_pmu_event_mask.isra.0+0x6c/0x74 [ 73.430779] sp : ffff80000a8db9b0 [ 73.434055] x29: ffff80000a8db9b0 x28: ffff000000dbaac0 x27: 0000000000000000 [ 73.441131] x26: ffff000000dbaac0 x25: 00000000c600000d x24: 0000000000180720 [ 73.448203] x23: ffff800009ffbe10 x22: ffff00000b612000 x21: 0000000000000000 [ 73.455276] x20: 000000000000001f x19: 0000000000000000 x18: ffffffffffffffff [ 73.462348] x17: 000000008003fe98 x16: 0000000000000000 x15: 0720072007200720 [ 73.469420] x14: 0720072007200720 x13: ffff800009d32488 x12: 00000000000004e6 [ 73.476493] x11: 00000000000001a2 x10: ffff800009d32488 x9 : ffff800009d32488 [ 73.483565] x8 : 00000000ffffefff x7 : ffff800009d8a488 x6 : ffff800009d8a488 [ 73.490638] x5 : ffff0000f461a9d8 x4 : 0000000000000000 x3 : 0000000000000001 [ 73.497710] x2 : 0000000000000000 x1 : 0000000000000000 x0 : ffff000000dbaac0 [ 73.504784] Call trace: [ 73.507195] kvm_pmu_event_mask.isra.0+0x6c/0x74 [ 73.511768] kvm_pmu_set_counter_event_type+0x2c/0x80 [ 73.516770] access_pmu_evtyper+0x128/0x16c [ 73.520910] perform_access+0x34/0x80 [ 73.524532] kvm_handle_cp_32+0x13c/0x160 [ 73.528500] kvm_handle_cp15_32+0x1c/0x30 [ 73.532467] handle_exit+0x70/0x180 [ 73.535917] kvm_arch_vcpu_ioctl_run+0x20c/0x6e0 [ 73.540489] kvm_vcpu_ioctl+0x2b8/0x9e0 [ 73.544283] __arm64_sys_ioctl+0xa8/0xf0 [ 73.548165] invoke_syscall+0x48/0x114 [ 73.551874] el0_svc_common.constprop.0+0xd4/0xfc [ 73.556531] do_el0_svc+0x28/0x90 [ 73.559808] el0_svc+0x28/0x80 [ 73.562826] el0t_64_sync_handler+0xa4/0x130 [ 73.567054] el0t_64_sync+0x1a0/0x1a4 [ 73.570676] ---[ end trace 0000000000000000 ]--- [ 73.575382] kvm: pmu event creation failed -2 The root cause remains the same: kvm->arch.pmuver was never set to something sensible because the VCPU feature itself was never set. The odroid-c4 is somewhat of a special case, because Linux doesn't probe the PMU. But the above errors can easily be reproduced on any hardware, with or without a PMU driver, as long as userspace doesn't set the PMU feature. Work around the fact that KVM advertises a PMU even when the VCPU feature is not set by gating all PMU emulation on the feature. The guest can still access the registers without KVM injecting an undefined exception. Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20220425145530.723858-1-alexandru.elisei@arm.com
2022-04-25 17:55:30 +03:00
if (!kvm_vcpu_has_pmu(vcpu))
return;
KVM: arm64: Use event mask matching architecture revision The PMU code suffers from a small defect where we assume that the event number provided by the guest is always 16 bit wide, even if the CPU only implements the ARMv8.0 architecture. This isn't really problematic in the sense that the event number ends up in a system register, cropping it to the right width, but still this needs fixing. In order to make it work, let's probe the version of the PMU that the guest is going to use. This is done by temporarily creating a kernel event and looking at the PMUVer field that has been saved at probe time in the associated arm_pmu structure. This in turn gets saved in the kvm structure, and subsequently used to compute the event mask that gets used throughout the PMU code. Signed-off-by: Marc Zyngier <maz@kernel.org>
2020-03-17 14:11:56 +03:00
mask = ARMV8_PMU_EVTYPE_MASK;
mask &= ~ARMV8_PMU_EVTYPE_EVENT;
mask |= kvm_pmu_event_mask(vcpu->kvm);
KVM: arm/arm64: Re-create event when setting counter value The perf event sample_period is currently set based upon the current counter value, when PMXEVTYPER is written to and the perf event is created. However the user may choose to write the type before the counter value in which case sample_period will be set incorrectly. Let's instead decouple event creation from PMXEVTYPER and (re)create the event in either suitation. Signed-off-by: Andrew Murray <andrew.murray@arm.com> Reviewed-by: Julien Thierry <julien.thierry@arm.com> Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2019-06-17 22:01:03 +03:00
KVM: arm64: PMU: Make kvm_pmc the main data structure The PMU code has historically been torn between referencing a counter as a pair vcpu+index or as the PMC pointer. Given that it is pretty easy to go from one representation to the other, standardise on the latter which, IMHO, makes the code slightly more readable. YMMV. Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221113163832.3154370-17-maz@kernel.org
2022-11-13 19:38:32 +03:00
reg = counter_index_to_evtreg(pmc->idx);
KVM: arm/arm64: Re-create event when setting counter value The perf event sample_period is currently set based upon the current counter value, when PMXEVTYPER is written to and the perf event is created. However the user may choose to write the type before the counter value in which case sample_period will be set incorrectly. Let's instead decouple event creation from PMXEVTYPER and (re)create the event in either suitation. Signed-off-by: Andrew Murray <andrew.murray@arm.com> Reviewed-by: Julien Thierry <julien.thierry@arm.com> Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2019-06-17 22:01:03 +03:00
KVM: arm64: Use event mask matching architecture revision The PMU code suffers from a small defect where we assume that the event number provided by the guest is always 16 bit wide, even if the CPU only implements the ARMv8.0 architecture. This isn't really problematic in the sense that the event number ends up in a system register, cropping it to the right width, but still this needs fixing. In order to make it work, let's probe the version of the PMU that the guest is going to use. This is done by temporarily creating a kernel event and looking at the PMUVer field that has been saved at probe time in the associated arm_pmu structure. This in turn gets saved in the kvm structure, and subsequently used to compute the event mask that gets used throughout the PMU code. Signed-off-by: Marc Zyngier <maz@kernel.org>
2020-03-17 14:11:56 +03:00
__vcpu_sys_reg(vcpu, reg) = data & mask;
KVM: arm/arm64: Support chained PMU counters ARMv8 provides support for chained PMU counters, where an event type of 0x001E is set for odd-numbered counters, the event counter will increment by one for each overflow of the preceding even-numbered counter. Let's emulate this in KVM by creating a 64 bit perf counter when a user chains two emulated counters together. For chained events we only support generating an overflow interrupt on the high counter. We use the attributes of the low counter to determine the attributes of the perf event. Suggested-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Andrew Murray <andrew.murray@arm.com> Reviewed-by: Julien Thierry <julien.thierry@arm.com> Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2019-06-17 22:01:05 +03:00
KVM: arm64: PMU: Make kvm_pmc the main data structure The PMU code has historically been torn between referencing a counter as a pair vcpu+index or as the PMC pointer. Given that it is pretty easy to go from one representation to the other, standardise on the latter which, IMHO, makes the code slightly more readable. YMMV. Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221113163832.3154370-17-maz@kernel.org
2022-11-13 19:38:32 +03:00
kvm_pmu_create_perf_event(pmc);
KVM: arm/arm64: Re-create event when setting counter value The perf event sample_period is currently set based upon the current counter value, when PMXEVTYPER is written to and the perf event is created. However the user may choose to write the type before the counter value in which case sample_period will be set incorrectly. Let's instead decouple event creation from PMXEVTYPER and (re)create the event in either suitation. Signed-off-by: Andrew Murray <andrew.murray@arm.com> Reviewed-by: Julien Thierry <julien.thierry@arm.com> Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2019-06-17 22:01:03 +03:00
}
KVM: arm64: Fix PMU probe ordering Russell reported that since 5.13, KVM's probing of the PMU has started to fail on his HW. As it turns out, there is an implicit ordering dependency between the architectural PMU probing code and and KVM's own probing. If, due to probe ordering reasons, KVM probes before the PMU driver, it will fail to detect the PMU and prevent it from being advertised to guests as well as the VMM. Obviously, this is one probing too many, and we should be able to deal with any ordering. Add a callback from the PMU code into KVM to advertise the registration of a host CPU PMU, allowing for any probing order. Fixes: 5421db1be3b1 ("KVM: arm64: Divorce the perf code from oprofile helpers") Reported-by: "Russell King (Oracle)" <linux@armlinux.org.uk> Tested-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/YUYRKVflRtUytzy5@shell.armlinux.org.uk Cc: stable@vger.kernel.org
2021-09-19 16:09:49 +03:00
void kvm_host_pmu_init(struct arm_pmu *pmu)
{
KVM: arm64: Keep a list of probed PMUs The ARM PMU driver calls kvm_host_pmu_init() after probing to tell KVM that a hardware PMU is available for guest emulation. Heterogeneous systems can have more than one PMU present, and the callback gets called multiple times, once for each of them. Keep track of all the PMUs available to KVM, as they're going to be needed later. Reviewed-by: Reiji Watanabe <reijiw@google.com> Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20220127161759.53553-5-alexandru.elisei@arm.com
2022-01-27 19:17:57 +03:00
struct arm_pmu_entry *entry;
KVM: arm64: PMU: Replace version number '0' with ID_AA64DFR0_EL1_PMUVer_NI kvm_host_pmu_init() returns when detected PMU is either not implemented, or implementation defined. kvm_pmu_probe_armpmu() also has a similar situation. Extracted ID_AA64DFR0_EL1_PMUVer value, when PMU is not implemented is '0', which can be replaced with ID_AA64DFR0_EL1_PMUVer_NI defined as '0b0000'. Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Marc Zyngier <maz@kernel.org> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Will Deacon <will@kernel.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: linux-perf-users@vger.kernel.org Cc: linux-kernel@vger.kernel.org Cc: linux-arm-kernel@lists.infradead.org Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221128135629.118346-1-anshuman.khandual@arm.com
2022-11-28 16:56:29 +03:00
if (pmu->pmuver == ID_AA64DFR0_EL1_PMUVer_NI ||
pmu->pmuver == ID_AA64DFR0_EL1_PMUVer_IMP_DEF)
KVM: arm64: Keep a list of probed PMUs The ARM PMU driver calls kvm_host_pmu_init() after probing to tell KVM that a hardware PMU is available for guest emulation. Heterogeneous systems can have more than one PMU present, and the callback gets called multiple times, once for each of them. Keep track of all the PMUs available to KVM, as they're going to be needed later. Reviewed-by: Reiji Watanabe <reijiw@google.com> Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20220127161759.53553-5-alexandru.elisei@arm.com
2022-01-27 19:17:57 +03:00
return;
mutex_lock(&arm_pmus_lock);
entry = kmalloc(sizeof(*entry), GFP_KERNEL);
if (!entry)
goto out_unlock;
entry->arm_pmu = pmu;
list_add_tail(&entry->entry, &arm_pmus);
if (list_is_singular(&arm_pmus))
KVM: arm64: Fix PMU probe ordering Russell reported that since 5.13, KVM's probing of the PMU has started to fail on his HW. As it turns out, there is an implicit ordering dependency between the architectural PMU probing code and and KVM's own probing. If, due to probe ordering reasons, KVM probes before the PMU driver, it will fail to detect the PMU and prevent it from being advertised to guests as well as the VMM. Obviously, this is one probing too many, and we should be able to deal with any ordering. Add a callback from the PMU code into KVM to advertise the registration of a host CPU PMU, allowing for any probing order. Fixes: 5421db1be3b1 ("KVM: arm64: Divorce the perf code from oprofile helpers") Reported-by: "Russell King (Oracle)" <linux@armlinux.org.uk> Tested-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/YUYRKVflRtUytzy5@shell.armlinux.org.uk Cc: stable@vger.kernel.org
2021-09-19 16:09:49 +03:00
static_branch_enable(&kvm_arm_pmu_available);
KVM: arm64: Keep a list of probed PMUs The ARM PMU driver calls kvm_host_pmu_init() after probing to tell KVM that a hardware PMU is available for guest emulation. Heterogeneous systems can have more than one PMU present, and the callback gets called multiple times, once for each of them. Keep track of all the PMUs available to KVM, as they're going to be needed later. Reviewed-by: Reiji Watanabe <reijiw@google.com> Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20220127161759.53553-5-alexandru.elisei@arm.com
2022-01-27 19:17:57 +03:00
out_unlock:
mutex_unlock(&arm_pmus_lock);
KVM: arm64: Fix PMU probe ordering Russell reported that since 5.13, KVM's probing of the PMU has started to fail on his HW. As it turns out, there is an implicit ordering dependency between the architectural PMU probing code and and KVM's own probing. If, due to probe ordering reasons, KVM probes before the PMU driver, it will fail to detect the PMU and prevent it from being advertised to guests as well as the VMM. Obviously, this is one probing too many, and we should be able to deal with any ordering. Add a callback from the PMU code into KVM to advertise the registration of a host CPU PMU, allowing for any probing order. Fixes: 5421db1be3b1 ("KVM: arm64: Divorce the perf code from oprofile helpers") Reported-by: "Russell King (Oracle)" <linux@armlinux.org.uk> Tested-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/YUYRKVflRtUytzy5@shell.armlinux.org.uk Cc: stable@vger.kernel.org
2021-09-19 16:09:49 +03:00
}
KVM: arm64: Keep a per-VM pointer to the default PMU As we are about to allow selection of the PMU exposed to a guest, start by keeping track of the default one instead of only the PMU version. Signed-off-by: Marc Zyngier <maz@kernel.org> Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com> Link: https://lore.kernel.org/r/20220127161759.53553-4-alexandru.elisei@arm.com
2022-01-27 19:17:56 +03:00
static struct arm_pmu *kvm_pmu_probe_armpmu(void)
KVM: arm64: Use event mask matching architecture revision The PMU code suffers from a small defect where we assume that the event number provided by the guest is always 16 bit wide, even if the CPU only implements the ARMv8.0 architecture. This isn't really problematic in the sense that the event number ends up in a system register, cropping it to the right width, but still this needs fixing. In order to make it work, let's probe the version of the PMU that the guest is going to use. This is done by temporarily creating a kernel event and looking at the PMUVer field that has been saved at probe time in the associated arm_pmu structure. This in turn gets saved in the kvm structure, and subsequently used to compute the event mask that gets used throughout the PMU code. Signed-off-by: Marc Zyngier <maz@kernel.org>
2020-03-17 14:11:56 +03:00
{
struct perf_event_attr attr = { };
struct perf_event *event;
KVM: arm64: Keep a per-VM pointer to the default PMU As we are about to allow selection of the PMU exposed to a guest, start by keeping track of the default one instead of only the PMU version. Signed-off-by: Marc Zyngier <maz@kernel.org> Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com> Link: https://lore.kernel.org/r/20220127161759.53553-4-alexandru.elisei@arm.com
2022-01-27 19:17:56 +03:00
struct arm_pmu *pmu = NULL;
KVM: arm64: Use event mask matching architecture revision The PMU code suffers from a small defect where we assume that the event number provided by the guest is always 16 bit wide, even if the CPU only implements the ARMv8.0 architecture. This isn't really problematic in the sense that the event number ends up in a system register, cropping it to the right width, but still this needs fixing. In order to make it work, let's probe the version of the PMU that the guest is going to use. This is done by temporarily creating a kernel event and looking at the PMUVer field that has been saved at probe time in the associated arm_pmu structure. This in turn gets saved in the kvm structure, and subsequently used to compute the event mask that gets used throughout the PMU code. Signed-off-by: Marc Zyngier <maz@kernel.org>
2020-03-17 14:11:56 +03:00
/*
* Create a dummy event that only counts user cycles. As we'll never
* leave this function with the event being live, it will never
* count anything. But it allows us to probe some of the PMU
* details. Yes, this is terrible.
*/
attr.type = PERF_TYPE_RAW;
attr.size = sizeof(attr);
attr.pinned = 1;
attr.disabled = 0;
attr.exclude_user = 0;
attr.exclude_kernel = 1;
attr.exclude_hv = 1;
attr.exclude_host = 1;
attr.config = ARMV8_PMUV3_PERFCTR_CPU_CYCLES;
attr.sample_period = GENMASK(63, 0);
event = perf_event_create_kernel_counter(&attr, -1, current,
kvm_pmu_perf_overflow, &attr);
if (IS_ERR(event)) {
pr_err_once("kvm: pmu event creation failed %ld\n",
PTR_ERR(event));
KVM: arm64: Keep a per-VM pointer to the default PMU As we are about to allow selection of the PMU exposed to a guest, start by keeping track of the default one instead of only the PMU version. Signed-off-by: Marc Zyngier <maz@kernel.org> Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com> Link: https://lore.kernel.org/r/20220127161759.53553-4-alexandru.elisei@arm.com
2022-01-27 19:17:56 +03:00
return NULL;
KVM: arm64: Use event mask matching architecture revision The PMU code suffers from a small defect where we assume that the event number provided by the guest is always 16 bit wide, even if the CPU only implements the ARMv8.0 architecture. This isn't really problematic in the sense that the event number ends up in a system register, cropping it to the right width, but still this needs fixing. In order to make it work, let's probe the version of the PMU that the guest is going to use. This is done by temporarily creating a kernel event and looking at the PMUVer field that has been saved at probe time in the associated arm_pmu structure. This in turn gets saved in the kvm structure, and subsequently used to compute the event mask that gets used throughout the PMU code. Signed-off-by: Marc Zyngier <maz@kernel.org>
2020-03-17 14:11:56 +03:00
}
if (event->pmu) {
pmu = to_arm_pmu(event->pmu);
KVM: arm64: PMU: Replace version number '0' with ID_AA64DFR0_EL1_PMUVer_NI kvm_host_pmu_init() returns when detected PMU is either not implemented, or implementation defined. kvm_pmu_probe_armpmu() also has a similar situation. Extracted ID_AA64DFR0_EL1_PMUVer value, when PMU is not implemented is '0', which can be replaced with ID_AA64DFR0_EL1_PMUVer_NI defined as '0b0000'. Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Marc Zyngier <maz@kernel.org> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Will Deacon <will@kernel.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: linux-perf-users@vger.kernel.org Cc: linux-kernel@vger.kernel.org Cc: linux-arm-kernel@lists.infradead.org Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221128135629.118346-1-anshuman.khandual@arm.com
2022-11-28 16:56:29 +03:00
if (pmu->pmuver == ID_AA64DFR0_EL1_PMUVer_NI ||
arm64/sysreg: Add _EL1 into ID_AA64DFR0_EL1 definition names Normally we include the full register name in the defines for fields within registers but this has not been followed for ID registers. In preparation for automatic generation of defines add the _EL1s into the defines for ID_AA64DFR0_EL1 to follow the convention. No functional changes. Signed-off-by: Mark Brown <broonie@kernel.org> Link: https://lore.kernel.org/r/20220910163354.860255-3-broonie@kernel.org Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2022-09-10 19:33:50 +03:00
pmu->pmuver == ID_AA64DFR0_EL1_PMUVer_IMP_DEF)
KVM: arm64: Keep a per-VM pointer to the default PMU As we are about to allow selection of the PMU exposed to a guest, start by keeping track of the default one instead of only the PMU version. Signed-off-by: Marc Zyngier <maz@kernel.org> Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com> Link: https://lore.kernel.org/r/20220127161759.53553-4-alexandru.elisei@arm.com
2022-01-27 19:17:56 +03:00
pmu = NULL;
KVM: arm64: Use event mask matching architecture revision The PMU code suffers from a small defect where we assume that the event number provided by the guest is always 16 bit wide, even if the CPU only implements the ARMv8.0 architecture. This isn't really problematic in the sense that the event number ends up in a system register, cropping it to the right width, but still this needs fixing. In order to make it work, let's probe the version of the PMU that the guest is going to use. This is done by temporarily creating a kernel event and looking at the PMUVer field that has been saved at probe time in the associated arm_pmu structure. This in turn gets saved in the kvm structure, and subsequently used to compute the event mask that gets used throughout the PMU code. Signed-off-by: Marc Zyngier <maz@kernel.org>
2020-03-17 14:11:56 +03:00
}
perf_event_disable(event);
perf_event_release_kernel(event);
KVM: arm64: Keep a per-VM pointer to the default PMU As we are about to allow selection of the PMU exposed to a guest, start by keeping track of the default one instead of only the PMU version. Signed-off-by: Marc Zyngier <maz@kernel.org> Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com> Link: https://lore.kernel.org/r/20220127161759.53553-4-alexandru.elisei@arm.com
2022-01-27 19:17:56 +03:00
return pmu;
KVM: arm64: Use event mask matching architecture revision The PMU code suffers from a small defect where we assume that the event number provided by the guest is always 16 bit wide, even if the CPU only implements the ARMv8.0 architecture. This isn't really problematic in the sense that the event number ends up in a system register, cropping it to the right width, but still this needs fixing. In order to make it work, let's probe the version of the PMU that the guest is going to use. This is done by temporarily creating a kernel event and looking at the PMUVer field that has been saved at probe time in the associated arm_pmu structure. This in turn gets saved in the kvm structure, and subsequently used to compute the event mask that gets used throughout the PMU code. Signed-off-by: Marc Zyngier <maz@kernel.org>
2020-03-17 14:11:56 +03:00
}
KVM: arm64: Mask out filtered events in PCMEID{0,1}_EL1 As we can now hide events from the guest, let's also adjust its view of PCMEID{0,1}_EL1 so that it can figure out why some common events are not counting as they should. The astute user can still look into the TRM for their CPU and find out they've been cheated, though. Nobody's perfect. Signed-off-by: Marc Zyngier <maz@kernel.org>
2020-03-12 19:11:24 +03:00
u64 kvm_pmu_get_pmceid(struct kvm_vcpu *vcpu, bool pmceid1)
{
unsigned long *bmap = vcpu->kvm->arch.pmu_filter;
u64 val, mask = 0;
KVM: arm64: Filter out v8.1+ events on v8.0 HW When running on v8.0 HW, make sure we don't try to advertise events in the 0x4000-0x403f range. Cc: stable@vger.kernel.org Fixes: 88865beca9062 ("KVM: arm64: Mask out filtered events in PCMEID{0,1}_EL1") Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20210121105636.1478491-1-maz@kernel.org
2021-01-21 13:56:36 +03:00
int base, i, nr_events;
KVM: arm64: Mask out filtered events in PCMEID{0,1}_EL1 As we can now hide events from the guest, let's also adjust its view of PCMEID{0,1}_EL1 so that it can figure out why some common events are not counting as they should. The astute user can still look into the TRM for their CPU and find out they've been cheated, though. Nobody's perfect. Signed-off-by: Marc Zyngier <maz@kernel.org>
2020-03-12 19:11:24 +03:00
KVM/arm64: Don't emulate a PMU for 32-bit guests if feature not set kvm->arch.arm_pmu is set when userspace attempts to set the first PMU attribute. As certain attributes are mandatory, arm_pmu ends up always being set to a valid arm_pmu, otherwise KVM will refuse to run the VCPU. However, this only happens if the VCPU has the PMU feature. If the VCPU doesn't have the feature bit set, kvm->arch.arm_pmu will be left uninitialized and equal to NULL. KVM doesn't do ID register emulation for 32-bit guests and accesses to the PMU registers aren't gated by the pmu_visibility() function. This is done to prevent injecting unexpected undefined exceptions in guests which have detected the presence of a hardware PMU. But even though the VCPU feature is missing, KVM still attempts to emulate certain aspects of the PMU when PMU registers are accessed. This leads to a NULL pointer dereference like this one, which happens on an odroid-c4 board when running the kvm-unit-tests pmu-cycle-counter test with kvmtool and without the PMU feature being set: [ 454.402699] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000150 [ 454.405865] Mem abort info: [ 454.408596] ESR = 0x96000004 [ 454.411638] EC = 0x25: DABT (current EL), IL = 32 bits [ 454.416901] SET = 0, FnV = 0 [ 454.419909] EA = 0, S1PTW = 0 [ 454.423010] FSC = 0x04: level 0 translation fault [ 454.427841] Data abort info: [ 454.430687] ISV = 0, ISS = 0x00000004 [ 454.434484] CM = 0, WnR = 0 [ 454.437404] user pgtable: 4k pages, 48-bit VAs, pgdp=000000000c924000 [ 454.443800] [0000000000000150] pgd=0000000000000000, p4d=0000000000000000 [ 454.450528] Internal error: Oops: 96000004 [#1] PREEMPT SMP [ 454.456036] Modules linked in: [ 454.459053] CPU: 1 PID: 267 Comm: kvm-vcpu-0 Not tainted 5.18.0-rc4 #113 [ 454.465697] Hardware name: Hardkernel ODROID-C4 (DT) [ 454.470612] pstate: 60400009 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) [ 454.477512] pc : kvm_pmu_event_mask.isra.0+0x14/0x74 [ 454.482427] lr : kvm_pmu_set_counter_event_type+0x2c/0x80 [ 454.487775] sp : ffff80000a9839c0 [ 454.491050] x29: ffff80000a9839c0 x28: ffff000000a83a00 x27: 0000000000000000 [ 454.498127] x26: 0000000000000000 x25: 0000000000000000 x24: ffff00000a510000 [ 454.505198] x23: ffff000000a83a00 x22: ffff000003b01000 x21: 0000000000000000 [ 454.512271] x20: 000000000000001f x19: 00000000000003ff x18: 0000000000000000 [ 454.519343] x17: 000000008003fe98 x16: 0000000000000000 x15: 0000000000000000 [ 454.526416] x14: 0000000000000000 x13: 0000000000000000 x12: 0000000000000000 [ 454.533489] x11: 000000008003fdbc x10: 0000000000009d20 x9 : 000000000000001b [ 454.540561] x8 : 0000000000000000 x7 : 0000000000000d00 x6 : 0000000000009d00 [ 454.547633] x5 : 0000000000000037 x4 : 0000000000009d00 x3 : 0d09000000000000 [ 454.554705] x2 : 000000000000001f x1 : 0000000000000000 x0 : 0000000000000000 [ 454.561779] Call trace: [ 454.564191] kvm_pmu_event_mask.isra.0+0x14/0x74 [ 454.568764] kvm_pmu_set_counter_event_type+0x2c/0x80 [ 454.573766] access_pmu_evtyper+0x128/0x170 [ 454.577905] perform_access+0x34/0x80 [ 454.581527] kvm_handle_cp_32+0x13c/0x160 [ 454.585495] kvm_handle_cp15_32+0x1c/0x30 [ 454.589462] handle_exit+0x70/0x180 [ 454.592912] kvm_arch_vcpu_ioctl_run+0x1c4/0x5e0 [ 454.597485] kvm_vcpu_ioctl+0x23c/0x940 [ 454.601280] __arm64_sys_ioctl+0xa8/0xf0 [ 454.605160] invoke_syscall+0x48/0x114 [ 454.608869] el0_svc_common.constprop.0+0xd4/0xfc [ 454.613527] do_el0_svc+0x28/0x90 [ 454.616803] el0_svc+0x34/0xb0 [ 454.619822] el0t_64_sync_handler+0xa4/0x130 [ 454.624049] el0t_64_sync+0x18c/0x190 [ 454.627675] Code: a9be7bfd 910003fd f9000bf3 52807ff3 (b9415001) [ 454.633714] ---[ end trace 0000000000000000 ]--- In this particular case, Linux hasn't detected the presence of a hardware PMU because the PMU node is missing from the DTB, so userspace would have been unable to set the VCPU PMU feature even if it attempted it. What happens is that the 32-bit guest reads ID_DFR0, which advertises the presence of the PMU, and when it tries to program a counter, it triggers the NULL pointer dereference because kvm->arch.arm_pmu is NULL. kvm-arch.arm_pmu was introduced by commit 46b187821472 ("KVM: arm64: Keep a per-VM pointer to the default PMU"). Until that commit, this error would be triggered instead: [ 73.388140] ------------[ cut here ]------------ [ 73.388189] Unknown PMU version 0 [ 73.390420] WARNING: CPU: 1 PID: 264 at arch/arm64/kvm/pmu-emul.c:36 kvm_pmu_event_mask.isra.0+0x6c/0x74 [ 73.399821] Modules linked in: [ 73.402835] CPU: 1 PID: 264 Comm: kvm-vcpu-0 Not tainted 5.17.0 #114 [ 73.409132] Hardware name: Hardkernel ODROID-C4 (DT) [ 73.414048] pstate: 60400009 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) [ 73.420948] pc : kvm_pmu_event_mask.isra.0+0x6c/0x74 [ 73.425863] lr : kvm_pmu_event_mask.isra.0+0x6c/0x74 [ 73.430779] sp : ffff80000a8db9b0 [ 73.434055] x29: ffff80000a8db9b0 x28: ffff000000dbaac0 x27: 0000000000000000 [ 73.441131] x26: ffff000000dbaac0 x25: 00000000c600000d x24: 0000000000180720 [ 73.448203] x23: ffff800009ffbe10 x22: ffff00000b612000 x21: 0000000000000000 [ 73.455276] x20: 000000000000001f x19: 0000000000000000 x18: ffffffffffffffff [ 73.462348] x17: 000000008003fe98 x16: 0000000000000000 x15: 0720072007200720 [ 73.469420] x14: 0720072007200720 x13: ffff800009d32488 x12: 00000000000004e6 [ 73.476493] x11: 00000000000001a2 x10: ffff800009d32488 x9 : ffff800009d32488 [ 73.483565] x8 : 00000000ffffefff x7 : ffff800009d8a488 x6 : ffff800009d8a488 [ 73.490638] x5 : ffff0000f461a9d8 x4 : 0000000000000000 x3 : 0000000000000001 [ 73.497710] x2 : 0000000000000000 x1 : 0000000000000000 x0 : ffff000000dbaac0 [ 73.504784] Call trace: [ 73.507195] kvm_pmu_event_mask.isra.0+0x6c/0x74 [ 73.511768] kvm_pmu_set_counter_event_type+0x2c/0x80 [ 73.516770] access_pmu_evtyper+0x128/0x16c [ 73.520910] perform_access+0x34/0x80 [ 73.524532] kvm_handle_cp_32+0x13c/0x160 [ 73.528500] kvm_handle_cp15_32+0x1c/0x30 [ 73.532467] handle_exit+0x70/0x180 [ 73.535917] kvm_arch_vcpu_ioctl_run+0x20c/0x6e0 [ 73.540489] kvm_vcpu_ioctl+0x2b8/0x9e0 [ 73.544283] __arm64_sys_ioctl+0xa8/0xf0 [ 73.548165] invoke_syscall+0x48/0x114 [ 73.551874] el0_svc_common.constprop.0+0xd4/0xfc [ 73.556531] do_el0_svc+0x28/0x90 [ 73.559808] el0_svc+0x28/0x80 [ 73.562826] el0t_64_sync_handler+0xa4/0x130 [ 73.567054] el0t_64_sync+0x1a0/0x1a4 [ 73.570676] ---[ end trace 0000000000000000 ]--- [ 73.575382] kvm: pmu event creation failed -2 The root cause remains the same: kvm->arch.pmuver was never set to something sensible because the VCPU feature itself was never set. The odroid-c4 is somewhat of a special case, because Linux doesn't probe the PMU. But the above errors can easily be reproduced on any hardware, with or without a PMU driver, as long as userspace doesn't set the PMU feature. Work around the fact that KVM advertises a PMU even when the VCPU feature is not set by gating all PMU emulation on the feature. The guest can still access the registers without KVM injecting an undefined exception. Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20220425145530.723858-1-alexandru.elisei@arm.com
2022-04-25 17:55:30 +03:00
if (!kvm_vcpu_has_pmu(vcpu))
return 0;
KVM: arm64: Mask out filtered events in PCMEID{0,1}_EL1 As we can now hide events from the guest, let's also adjust its view of PCMEID{0,1}_EL1 so that it can figure out why some common events are not counting as they should. The astute user can still look into the TRM for their CPU and find out they've been cheated, though. Nobody's perfect. Signed-off-by: Marc Zyngier <maz@kernel.org>
2020-03-12 19:11:24 +03:00
if (!pmceid1) {
val = read_sysreg(pmceid0_el0);
KVM: arm64: PMU: Always advertise the CHAIN event Even when the underlying HW doesn't offer the CHAIN event (which happens with QEMU), we can always support it as we're in control of the counter overflow. Always advertise the event via PMCEID0_EL0. Reviewed-by: Reiji Watanabe <reijiw@google.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221113163832.3154370-4-maz@kernel.org
2022-11-13 19:38:19 +03:00
/* always support CHAIN */
val |= BIT(ARMV8_PMUV3_PERFCTR_CHAIN);
KVM: arm64: Mask out filtered events in PCMEID{0,1}_EL1 As we can now hide events from the guest, let's also adjust its view of PCMEID{0,1}_EL1 so that it can figure out why some common events are not counting as they should. The astute user can still look into the TRM for their CPU and find out they've been cheated, though. Nobody's perfect. Signed-off-by: Marc Zyngier <maz@kernel.org>
2020-03-12 19:11:24 +03:00
base = 0;
} else {
val = read_sysreg(pmceid1_el0);
KVM: arm64: Upgrade PMU support to ARMv8.4 Upgrading the PMU code from ARMv8.1 to ARMv8.4 turns out to be pretty easy. All that is required is support for PMMIR_EL1, which is read-only, and for which returning 0 is a valid option as long as we don't advertise STALL_SLOT as an implemented event. Let's just do that and adjust what we return to the guest. Signed-off-by: Marc Zyngier <maz@kernel.org>
2020-02-16 21:17:22 +03:00
/*
* Don't advertise STALL_SLOT, as PMMIR_EL0 is handled
* as RAZ
*/
arm64/sysreg: Use feature numbering for PMU and SPE revisions Currently the kernel refers to the versions of the PMU and SPE features by the version of the architecture where those features were updated but the ARM refers to them using the FEAT_ names for the features. To improve consistency and help with updating for newer features and since v9 will make our current naming scheme a bit more confusing update the macros identfying features to use the FEAT_ based scheme. Signed-off-by: Mark Brown <broonie@kernel.org> Link: https://lore.kernel.org/r/20220910163354.860255-4-broonie@kernel.org Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2022-09-10 19:33:51 +03:00
if (vcpu->kvm->arch.arm_pmu->pmuver >= ID_AA64DFR0_EL1_PMUVer_V3P4)
KVM: arm64: Upgrade PMU support to ARMv8.4 Upgrading the PMU code from ARMv8.1 to ARMv8.4 turns out to be pretty easy. All that is required is support for PMMIR_EL1, which is read-only, and for which returning 0 is a valid option as long as we don't advertise STALL_SLOT as an implemented event. Let's just do that and adjust what we return to the guest. Signed-off-by: Marc Zyngier <maz@kernel.org>
2020-02-16 21:17:22 +03:00
val &= ~BIT_ULL(ARMV8_PMUV3_PERFCTR_STALL_SLOT - 32);
KVM: arm64: Mask out filtered events in PCMEID{0,1}_EL1 As we can now hide events from the guest, let's also adjust its view of PCMEID{0,1}_EL1 so that it can figure out why some common events are not counting as they should. The astute user can still look into the TRM for their CPU and find out they've been cheated, though. Nobody's perfect. Signed-off-by: Marc Zyngier <maz@kernel.org>
2020-03-12 19:11:24 +03:00
base = 32;
}
if (!bmap)
return val;
KVM: arm64: Filter out v8.1+ events on v8.0 HW When running on v8.0 HW, make sure we don't try to advertise events in the 0x4000-0x403f range. Cc: stable@vger.kernel.org Fixes: 88865beca9062 ("KVM: arm64: Mask out filtered events in PCMEID{0,1}_EL1") Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20210121105636.1478491-1-maz@kernel.org
2021-01-21 13:56:36 +03:00
nr_events = kvm_pmu_event_mask(vcpu->kvm) + 1;
KVM: arm64: Mask out filtered events in PCMEID{0,1}_EL1 As we can now hide events from the guest, let's also adjust its view of PCMEID{0,1}_EL1 so that it can figure out why some common events are not counting as they should. The astute user can still look into the TRM for their CPU and find out they've been cheated, though. Nobody's perfect. Signed-off-by: Marc Zyngier <maz@kernel.org>
2020-03-12 19:11:24 +03:00
for (i = 0; i < 32; i += 8) {
u64 byte;
byte = bitmap_get_value8(bmap, base + i);
mask |= byte << i;
KVM: arm64: Filter out v8.1+ events on v8.0 HW When running on v8.0 HW, make sure we don't try to advertise events in the 0x4000-0x403f range. Cc: stable@vger.kernel.org Fixes: 88865beca9062 ("KVM: arm64: Mask out filtered events in PCMEID{0,1}_EL1") Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20210121105636.1478491-1-maz@kernel.org
2021-01-21 13:56:36 +03:00
if (nr_events >= (0x4000 + base + 32)) {
byte = bitmap_get_value8(bmap, 0x4000 + base + i);
mask |= byte << (32 + i);
}
KVM: arm64: Mask out filtered events in PCMEID{0,1}_EL1 As we can now hide events from the guest, let's also adjust its view of PCMEID{0,1}_EL1 so that it can figure out why some common events are not counting as they should. The astute user can still look into the TRM for their CPU and find out they've been cheated, though. Nobody's perfect. Signed-off-by: Marc Zyngier <maz@kernel.org>
2020-03-12 19:11:24 +03:00
}
return val & mask;
}
KVM: arm64: Allow creating the PMU without the in-kernel GIC Since we got support for devices in userspace which allows reporting the PMU overflow output status to userspace, we should actually allow creating the PMU on systems without an in-kernel irqchip, which in turn requires us to slightly clarify error codes for the ABI and move things around for the initialization phase. Signed-off-by: Christoffer Dall <cdall@linaro.org> Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
2017-05-02 14:41:02 +03:00
int kvm_arm_pmu_v3_enable(struct kvm_vcpu *vcpu)
arm64: KVM: Add a new vcpu device control group for PMUv3 To configure the virtual PMUv3 overflow interrupt number, we use the vcpu kvm_device ioctl, encapsulating the KVM_ARM_VCPU_PMU_V3_IRQ attribute within the KVM_ARM_VCPU_PMU_V3_CTRL group. After configuring the PMUv3, call the vcpu ioctl with attribute KVM_ARM_VCPU_PMU_V3_INIT to initialize the PMUv3. Signed-off-by: Shannon Zhao <shannon.zhao@linaro.org> Acked-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Andrew Jones <drjones@redhat.com> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2016-01-11 16:35:32 +03:00
{
KVM: arm64: Refuse to run VCPU if PMU is not initialized When enabling the PMU in kvm_arm_pmu_v3_enable(), KVM returns early if the PMU flag created is false and skips any other checks. Because PMU emulation is gated only on the VCPU feature being set, this makes it possible for userspace to get away with setting the VCPU feature but not doing any initialization for the PMU. Fix it by returning an error when trying to run the VCPU if the PMU hasn't been initialized correctly. The PMU is marked as created only if the interrupt ID has been set when using an in-kernel irqchip. This means the same check in kvm_arm_pmu_v3_enable() is redundant, remove it. Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20201126144916.164075-1-alexandru.elisei@arm.com
2020-11-26 17:49:16 +03:00
if (!kvm_vcpu_has_pmu(vcpu))
KVM: arm64: Allow creating the PMU without the in-kernel GIC Since we got support for devices in userspace which allows reporting the PMU overflow output status to userspace, we should actually allow creating the PMU on systems without an in-kernel irqchip, which in turn requires us to slightly clarify error codes for the ABI and move things around for the initialization phase. Signed-off-by: Christoffer Dall <cdall@linaro.org> Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
2017-05-02 14:41:02 +03:00
return 0;
arm64: KVM: Add a new vcpu device control group for PMUv3 To configure the virtual PMUv3 overflow interrupt number, we use the vcpu kvm_device ioctl, encapsulating the KVM_ARM_VCPU_PMU_V3_IRQ attribute within the KVM_ARM_VCPU_PMU_V3_CTRL group. After configuring the PMUv3, call the vcpu ioctl with attribute KVM_ARM_VCPU_PMU_V3_INIT to initialize the PMUv3. Signed-off-by: Shannon Zhao <shannon.zhao@linaro.org> Acked-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Andrew Jones <drjones@redhat.com> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2016-01-11 16:35:32 +03:00
KVM: arm64: Refuse to run VCPU if PMU is not initialized When enabling the PMU in kvm_arm_pmu_v3_enable(), KVM returns early if the PMU flag created is false and skips any other checks. Because PMU emulation is gated only on the VCPU feature being set, this makes it possible for userspace to get away with setting the VCPU feature but not doing any initialization for the PMU. Fix it by returning an error when trying to run the VCPU if the PMU hasn't been initialized correctly. The PMU is marked as created only if the interrupt ID has been set when using an in-kernel irqchip. This means the same check in kvm_arm_pmu_v3_enable() is redundant, remove it. Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20201126144916.164075-1-alexandru.elisei@arm.com
2020-11-26 17:49:16 +03:00
if (!vcpu->arch.pmu.created)
return -EINVAL;
KVM: arm64: Require in-kernel irqchip for PMU support If userspace creates a PMU for the VCPU, but doesn't create an in-kernel irqchip, then we end up in a nasty path where we try to take an uninitialized spinlock, which can lead to all sorts of breakages. Luckily, QEMU always creates the VGIC before the PMU, so we can establish this as ABI and check for the VGIC in the PMU init stage. This can be relaxed at a later time if we want to support PMU with a userspace irqchip. Cc: stable@vger.kernel.org Cc: Shannon Zhao <shannon.zhao@linaro.org> Acked-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
2016-09-27 04:51:47 +03:00
/*
KVM: arm64: Allow creating the PMU without the in-kernel GIC Since we got support for devices in userspace which allows reporting the PMU overflow output status to userspace, we should actually allow creating the PMU on systems without an in-kernel irqchip, which in turn requires us to slightly clarify error codes for the ABI and move things around for the initialization phase. Signed-off-by: Christoffer Dall <cdall@linaro.org> Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
2017-05-02 14:41:02 +03:00
* A valid interrupt configuration for the PMU is either to have a
* properly configured interrupt number and using an in-kernel
KVM: arm/arm64: Don't assume initialized vgic when setting PMU IRQ The PMU IRQ number is set through the VCPU device's KVM_SET_DEVICE_ATTR ioctl handler for the KVM_ARM_VCPU_PMU_V3_IRQ attribute, but there is no enforced or stated requirement that this must happen after initializing the VGIC. As a result, calling vgic_valid_spi() which relies on the nr_spis being set during the VGIC init can incorrectly fail. Introduce irq_is_spi, which determines if an IRQ number is within the SPI range without verifying it against the actual VGIC properties. Signed-off-by: Christoffer Dall <cdall@linaro.org> Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
2017-05-16 20:53:50 +03:00
* irqchip, or to not have an in-kernel GIC and not set an IRQ.
KVM: arm64: Require in-kernel irqchip for PMU support If userspace creates a PMU for the VCPU, but doesn't create an in-kernel irqchip, then we end up in a nasty path where we try to take an uninitialized spinlock, which can lead to all sorts of breakages. Luckily, QEMU always creates the VGIC before the PMU, so we can establish this as ABI and check for the VGIC in the PMU init stage. This can be relaxed at a later time if we want to support PMU with a userspace irqchip. Cc: stable@vger.kernel.org Cc: Shannon Zhao <shannon.zhao@linaro.org> Acked-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
2016-09-27 04:51:47 +03:00
*/
KVM: arm/arm64: Don't assume initialized vgic when setting PMU IRQ The PMU IRQ number is set through the VCPU device's KVM_SET_DEVICE_ATTR ioctl handler for the KVM_ARM_VCPU_PMU_V3_IRQ attribute, but there is no enforced or stated requirement that this must happen after initializing the VGIC. As a result, calling vgic_valid_spi() which relies on the nr_spis being set during the VGIC init can incorrectly fail. Introduce irq_is_spi, which determines if an IRQ number is within the SPI range without verifying it against the actual VGIC properties. Signed-off-by: Christoffer Dall <cdall@linaro.org> Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
2017-05-16 20:53:50 +03:00
if (irqchip_in_kernel(vcpu->kvm)) {
int irq = vcpu->arch.pmu.irq_num;
/*
* If we are using an in-kernel vgic, at this point we know
* the vgic will be initialized, so we can check the PMU irq
* number against the dimensions of the vgic and make sure
* it's valid.
*/
if (!irq_is_ppi(irq) && !vgic_valid_spi(vcpu->kvm, irq))
return -EINVAL;
} else if (kvm_arm_pmu_irq_initialized(vcpu)) {
return -EINVAL;
}
KVM: arm64: Allow creating the PMU without the in-kernel GIC Since we got support for devices in userspace which allows reporting the PMU overflow output status to userspace, we should actually allow creating the PMU on systems without an in-kernel irqchip, which in turn requires us to slightly clarify error codes for the ABI and move things around for the initialization phase. Signed-off-by: Christoffer Dall <cdall@linaro.org> Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
2017-05-02 14:41:02 +03:00
KVM: arm64: Restore PMU configuration on first run Restoring a guest with an active virtual PMU results in no perf counters being instanciated on the host side. Not quite what you'd expect from a restore. In order to fix this, force a writeback of PMCR_EL0 on the first run of a vcpu (using a new request so that it happens once the vcpu has been loaded). This will in turn create all the host-side counters that were missing. Reported-by: Jinank Jain <jinankj@amazon.de> Tested-by: Jinank Jain <jinankj@amazon.de> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/87wnrbylxv.wl-maz@kernel.org Link: https://lore.kernel.org/r/b53dfcf9bbc4db7f96154b1cd5188d72b9766358.camel@amazon.de
2021-06-03 18:50:02 +03:00
/* One-off reload of the PMU on first run */
kvm_make_request(KVM_REQ_RELOAD_PMU, vcpu);
KVM: arm64: Allow creating the PMU without the in-kernel GIC Since we got support for devices in userspace which allows reporting the PMU overflow output status to userspace, we should actually allow creating the PMU on systems without an in-kernel irqchip, which in turn requires us to slightly clarify error codes for the ABI and move things around for the initialization phase. Signed-off-by: Christoffer Dall <cdall@linaro.org> Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
2017-05-02 14:41:02 +03:00
return 0;
}
static int kvm_arm_pmu_v3_init(struct kvm_vcpu *vcpu)
{
if (irqchip_in_kernel(vcpu->kvm)) {
KVM: arm/arm64: Check if irq lines to the GIC are already used We check if other in-kernel devices have already been connected to the GIC for a particular interrupt line when possible. For the PMU, we can do this whenever setting the PMU interrupt number from userspace. For the timers, we have to wait until we try to enable the timer, because we have a concept of default IRQ numbers that userspace shouldn't have to work around in the initialization phase. Signed-off-by: Christoffer Dall <cdall@linaro.org> Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
2017-05-04 14:32:53 +03:00
int ret;
KVM: arm64: Allow creating the PMU without the in-kernel GIC Since we got support for devices in userspace which allows reporting the PMU overflow output status to userspace, we should actually allow creating the PMU on systems without an in-kernel irqchip, which in turn requires us to slightly clarify error codes for the ABI and move things around for the initialization phase. Signed-off-by: Christoffer Dall <cdall@linaro.org> Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
2017-05-02 14:41:02 +03:00
/*
* If using the PMU with an in-kernel virtual GIC
* implementation, we require the GIC to be already
* initialized when initializing the PMU.
*/
if (!vgic_initialized(vcpu->kvm))
return -ENODEV;
if (!kvm_arm_pmu_irq_initialized(vcpu))
return -ENXIO;
KVM: arm/arm64: Check if irq lines to the GIC are already used We check if other in-kernel devices have already been connected to the GIC for a particular interrupt line when possible. For the PMU, we can do this whenever setting the PMU interrupt number from userspace. For the timers, we have to wait until we try to enable the timer, because we have a concept of default IRQ numbers that userspace shouldn't have to work around in the initialization phase. Signed-off-by: Christoffer Dall <cdall@linaro.org> Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
2017-05-04 14:32:53 +03:00
ret = kvm_vgic_set_owner(vcpu, vcpu->arch.pmu.irq_num,
&vcpu->arch.pmu);
if (ret)
return ret;
KVM: arm64: Allow creating the PMU without the in-kernel GIC Since we got support for devices in userspace which allows reporting the PMU overflow output status to userspace, we should actually allow creating the PMU on systems without an in-kernel irqchip, which in turn requires us to slightly clarify error codes for the ABI and move things around for the initialization phase. Signed-off-by: Christoffer Dall <cdall@linaro.org> Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
2017-05-02 14:41:02 +03:00
}
arm64: KVM: Add a new vcpu device control group for PMUv3 To configure the virtual PMUv3 overflow interrupt number, we use the vcpu kvm_device ioctl, encapsulating the KVM_ARM_VCPU_PMU_V3_IRQ attribute within the KVM_ARM_VCPU_PMU_V3_CTRL group. After configuring the PMUv3, call the vcpu ioctl with attribute KVM_ARM_VCPU_PMU_V3_INIT to initialize the PMUv3. Signed-off-by: Shannon Zhao <shannon.zhao@linaro.org> Acked-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Andrew Jones <drjones@redhat.com> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2016-01-11 16:35:32 +03:00
KVM: arm64: pmu: Make overflow handler NMI safe kvm_vcpu_kick() is not NMI safe. When the overflow handler is called from NMI context, defer waking the vcpu to an irq_work queue. A vcpu can be freed while it's not running by kvm_destroy_vm(). Prevent running the irq_work for a non-existent vcpu by calling irq_work_sync() on the PMU destroy path. [Alexandru E.: Added irq_work_sync()] Signed-off-by: Julien Thierry <julien.thierry@arm.com> Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com> Tested-by: Sumit Garg <sumit.garg@linaro.org> (Developerbox) Cc: Julien Thierry <julien.thierry.kdev@gmail.com> Cc: Marc Zyngier <marc.zyngier@arm.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: James Morse <james.morse@arm.com> Cc: Suzuki K Pouloze <suzuki.poulose@arm.com> Cc: kvm@vger.kernel.org Cc: kvmarm@lists.cs.columbia.edu Link: https://lore.kernel.org/r/20200924110706.254996-6-alexandru.elisei@arm.com Signed-off-by: Will Deacon <will@kernel.org>
2020-09-24 14:07:04 +03:00
init_irq_work(&vcpu->arch.pmu.overflow_work,
kvm_pmu_perf_overflow_notify_vcpu);
KVM: arm64: Allow creating the PMU without the in-kernel GIC Since we got support for devices in userspace which allows reporting the PMU overflow output status to userspace, we should actually allow creating the PMU on systems without an in-kernel irqchip, which in turn requires us to slightly clarify error codes for the ABI and move things around for the initialization phase. Signed-off-by: Christoffer Dall <cdall@linaro.org> Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
2017-05-02 14:41:02 +03:00
vcpu->arch.pmu.created = true;
arm64: KVM: Add a new vcpu device control group for PMUv3 To configure the virtual PMUv3 overflow interrupt number, we use the vcpu kvm_device ioctl, encapsulating the KVM_ARM_VCPU_PMU_V3_IRQ attribute within the KVM_ARM_VCPU_PMU_V3_CTRL group. After configuring the PMUv3, call the vcpu ioctl with attribute KVM_ARM_VCPU_PMU_V3_INIT to initialize the PMUv3. Signed-off-by: Shannon Zhao <shannon.zhao@linaro.org> Acked-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Andrew Jones <drjones@redhat.com> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2016-01-11 16:35:32 +03:00
return 0;
}
KVM: arm/arm64: pmu: abstract access to number of SPIs Currently the PMU uses a member of the struct vgic_dist directly, which not only breaks abstraction, but will fail with the new VGIC. Abstract this access in the VGIC header file and refactor the validity check in the PMU code. Signed-off-by: Andre Przywara <andre.przywara@arm.com>
2016-03-07 13:32:29 +03:00
/*
* For one VM the interrupt type must be same for each vcpu.
* As a PPI, the interrupt number is the same for all vcpus,
* while as an SPI it must be a separate number per vcpu.
*/
static bool pmu_irq_is_valid(struct kvm *kvm, int irq)
arm64: KVM: Add a new vcpu device control group for PMUv3 To configure the virtual PMUv3 overflow interrupt number, we use the vcpu kvm_device ioctl, encapsulating the KVM_ARM_VCPU_PMU_V3_IRQ attribute within the KVM_ARM_VCPU_PMU_V3_CTRL group. After configuring the PMUv3, call the vcpu ioctl with attribute KVM_ARM_VCPU_PMU_V3_INIT to initialize the PMUv3. Signed-off-by: Shannon Zhao <shannon.zhao@linaro.org> Acked-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Andrew Jones <drjones@redhat.com> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2016-01-11 16:35:32 +03:00
{
KVM: Use 'unsigned long' as kvm_for_each_vcpu()'s index Everywhere we use kvm_for_each_vpcu(), we use an int as the vcpu index. Unfortunately, we're about to move rework the iterator, which requires this to be upgrade to an unsigned long. Let's bite the bullet and repaint all of it in one go. Signed-off-by: Marc Zyngier <maz@kernel.org> Message-Id: <20211116160403.4074052-7-maz@kernel.org> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-11-16 19:04:02 +03:00
unsigned long i;
arm64: KVM: Add a new vcpu device control group for PMUv3 To configure the virtual PMUv3 overflow interrupt number, we use the vcpu kvm_device ioctl, encapsulating the KVM_ARM_VCPU_PMU_V3_IRQ attribute within the KVM_ARM_VCPU_PMU_V3_CTRL group. After configuring the PMUv3, call the vcpu ioctl with attribute KVM_ARM_VCPU_PMU_V3_INIT to initialize the PMUv3. Signed-off-by: Shannon Zhao <shannon.zhao@linaro.org> Acked-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Andrew Jones <drjones@redhat.com> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2016-01-11 16:35:32 +03:00
struct kvm_vcpu *vcpu;
kvm_for_each_vcpu(i, vcpu, kvm) {
if (!kvm_arm_pmu_irq_initialized(vcpu))
continue;
KVM: arm/arm64: pmu: abstract access to number of SPIs Currently the PMU uses a member of the struct vgic_dist directly, which not only breaks abstraction, but will fail with the new VGIC. Abstract this access in the VGIC header file and refactor the validity check in the PMU code. Signed-off-by: Andre Przywara <andre.przywara@arm.com>
2016-03-07 13:32:29 +03:00
if (irq_is_ppi(irq)) {
arm64: KVM: Add a new vcpu device control group for PMUv3 To configure the virtual PMUv3 overflow interrupt number, we use the vcpu kvm_device ioctl, encapsulating the KVM_ARM_VCPU_PMU_V3_IRQ attribute within the KVM_ARM_VCPU_PMU_V3_CTRL group. After configuring the PMUv3, call the vcpu ioctl with attribute KVM_ARM_VCPU_PMU_V3_INIT to initialize the PMUv3. Signed-off-by: Shannon Zhao <shannon.zhao@linaro.org> Acked-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Andrew Jones <drjones@redhat.com> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2016-01-11 16:35:32 +03:00
if (vcpu->arch.pmu.irq_num != irq)
return false;
} else {
if (vcpu->arch.pmu.irq_num == irq)
return false;
}
}
return true;
}
KVM: arm64: Add KVM_ARM_VCPU_PMU_V3_SET_PMU attribute When KVM creates an event and there are more than one PMUs present on the system, perf_init_event() will go through the list of available PMUs and will choose the first one that can create the event. The order of the PMUs in this list depends on the probe order, which can change under various circumstances, for example if the order of the PMU nodes change in the DTB or if asynchronous driver probing is enabled on the kernel command line (with the driver_async_probe=armv8-pmu option). Another consequence of this approach is that on heteregeneous systems all virtual machines that KVM creates will use the same PMU. This might cause unexpected behaviour for userspace: when a VCPU is executing on the physical CPU that uses this default PMU, PMU events in the guest work correctly; but when the same VCPU executes on another CPU, PMU events in the guest will suddenly stop counting. Fortunately, perf core allows user to specify on which PMU to create an event by using the perf_event_attr->type field, which is used by perf_init_event() as an index in the radix tree of available PMUs. Add the KVM_ARM_VCPU_PMU_V3_CTRL(KVM_ARM_VCPU_PMU_V3_SET_PMU) VCPU attribute to allow userspace to specify the arm_pmu that KVM will use when creating events for that VCPU. KVM will make no attempt to run the VCPU on the physical CPUs that share the PMU, leaving it up to userspace to manage the VCPU threads' affinity accordingly. To ensure that KVM doesn't expose an asymmetric system to the guest, the PMU set for one VCPU will be used by all other VCPUs. Once a VCPU has run, the PMU cannot be changed in order to avoid changing the list of available events for a VCPU, or to change the semantics of existing events. Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20220127161759.53553-6-alexandru.elisei@arm.com
2022-01-27 19:17:58 +03:00
static int kvm_arm_pmu_v3_set_pmu(struct kvm_vcpu *vcpu, int pmu_id)
{
struct kvm *kvm = vcpu->kvm;
struct arm_pmu_entry *entry;
struct arm_pmu *arm_pmu;
int ret = -ENXIO;
mutex_lock(&kvm->lock);
mutex_lock(&arm_pmus_lock);
list_for_each_entry(entry, &arm_pmus, entry) {
arm_pmu = entry->arm_pmu;
if (arm_pmu->pmu.type == pmu_id) {
KVM: arm64: Generalise VM features into a set of flags We currently deal with a set of booleans for VM features, while they could be better represented as set of flags contained in an unsigned long, similarily to what we are doing on the CPU side. Signed-off-by: Marc Zyngier <maz@kernel.org> [Oliver: Flag-ify the 'ran_once' boolean] Signed-off-by: Oliver Upton <oupton@google.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20220311174001.605719-2-oupton@google.com
2022-03-11 20:39:47 +03:00
if (test_bit(KVM_ARCH_FLAG_HAS_RAN_ONCE, &kvm->arch.flags) ||
KVM: arm64: Add KVM_ARM_VCPU_PMU_V3_SET_PMU attribute When KVM creates an event and there are more than one PMUs present on the system, perf_init_event() will go through the list of available PMUs and will choose the first one that can create the event. The order of the PMUs in this list depends on the probe order, which can change under various circumstances, for example if the order of the PMU nodes change in the DTB or if asynchronous driver probing is enabled on the kernel command line (with the driver_async_probe=armv8-pmu option). Another consequence of this approach is that on heteregeneous systems all virtual machines that KVM creates will use the same PMU. This might cause unexpected behaviour for userspace: when a VCPU is executing on the physical CPU that uses this default PMU, PMU events in the guest work correctly; but when the same VCPU executes on another CPU, PMU events in the guest will suddenly stop counting. Fortunately, perf core allows user to specify on which PMU to create an event by using the perf_event_attr->type field, which is used by perf_init_event() as an index in the radix tree of available PMUs. Add the KVM_ARM_VCPU_PMU_V3_CTRL(KVM_ARM_VCPU_PMU_V3_SET_PMU) VCPU attribute to allow userspace to specify the arm_pmu that KVM will use when creating events for that VCPU. KVM will make no attempt to run the VCPU on the physical CPUs that share the PMU, leaving it up to userspace to manage the VCPU threads' affinity accordingly. To ensure that KVM doesn't expose an asymmetric system to the guest, the PMU set for one VCPU will be used by all other VCPUs. Once a VCPU has run, the PMU cannot be changed in order to avoid changing the list of available events for a VCPU, or to change the semantics of existing events. Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20220127161759.53553-6-alexandru.elisei@arm.com
2022-01-27 19:17:58 +03:00
(kvm->arch.pmu_filter && kvm->arch.arm_pmu != arm_pmu)) {
ret = -EBUSY;
break;
}
kvm->arch.arm_pmu = arm_pmu;
KVM: arm64: Refuse to run VCPU if the PMU doesn't match the physical CPU Userspace can assign a PMU to a VCPU with the KVM_ARM_VCPU_PMU_V3_SET_PMU device ioctl. If the VCPU is scheduled on a physical CPU which has a different PMU, the perf events needed to emulate a guest PMU won't be scheduled in and the guest performance counters will stop counting. Treat it as an userspace error and refuse to run the VCPU in this situation. Suggested-by: Marc Zyngier <maz@kernel.org> Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20220127161759.53553-7-alexandru.elisei@arm.com
2022-01-27 19:17:59 +03:00
cpumask_copy(kvm->arch.supported_cpus, &arm_pmu->supported_cpus);
KVM: arm64: Add KVM_ARM_VCPU_PMU_V3_SET_PMU attribute When KVM creates an event and there are more than one PMUs present on the system, perf_init_event() will go through the list of available PMUs and will choose the first one that can create the event. The order of the PMUs in this list depends on the probe order, which can change under various circumstances, for example if the order of the PMU nodes change in the DTB or if asynchronous driver probing is enabled on the kernel command line (with the driver_async_probe=armv8-pmu option). Another consequence of this approach is that on heteregeneous systems all virtual machines that KVM creates will use the same PMU. This might cause unexpected behaviour for userspace: when a VCPU is executing on the physical CPU that uses this default PMU, PMU events in the guest work correctly; but when the same VCPU executes on another CPU, PMU events in the guest will suddenly stop counting. Fortunately, perf core allows user to specify on which PMU to create an event by using the perf_event_attr->type field, which is used by perf_init_event() as an index in the radix tree of available PMUs. Add the KVM_ARM_VCPU_PMU_V3_CTRL(KVM_ARM_VCPU_PMU_V3_SET_PMU) VCPU attribute to allow userspace to specify the arm_pmu that KVM will use when creating events for that VCPU. KVM will make no attempt to run the VCPU on the physical CPUs that share the PMU, leaving it up to userspace to manage the VCPU threads' affinity accordingly. To ensure that KVM doesn't expose an asymmetric system to the guest, the PMU set for one VCPU will be used by all other VCPUs. Once a VCPU has run, the PMU cannot be changed in order to avoid changing the list of available events for a VCPU, or to change the semantics of existing events. Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20220127161759.53553-6-alexandru.elisei@arm.com
2022-01-27 19:17:58 +03:00
ret = 0;
break;
}
}
mutex_unlock(&arm_pmus_lock);
mutex_unlock(&kvm->lock);
return ret;
}
arm64: KVM: Add a new vcpu device control group for PMUv3 To configure the virtual PMUv3 overflow interrupt number, we use the vcpu kvm_device ioctl, encapsulating the KVM_ARM_VCPU_PMU_V3_IRQ attribute within the KVM_ARM_VCPU_PMU_V3_CTRL group. After configuring the PMUv3, call the vcpu ioctl with attribute KVM_ARM_VCPU_PMU_V3_INIT to initialize the PMUv3. Signed-off-by: Shannon Zhao <shannon.zhao@linaro.org> Acked-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Andrew Jones <drjones@redhat.com> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2016-01-11 16:35:32 +03:00
int kvm_arm_pmu_v3_set_attr(struct kvm_vcpu *vcpu, struct kvm_device_attr *attr)
{
KVM: arm64: Do not change the PMU event filter after a VCPU has run Userspace can specify which events a guest is allowed to use with the KVM_ARM_VCPU_PMU_V3_FILTER attribute. The list of allowed events can be identified by a guest from reading the PMCEID{0,1}_EL0 registers. Changing the PMU event filter after a VCPU has run can cause reads of the registers performed before the filter is changed to return different values than reads performed with the new event filter in place. The architecture defines the two registers as read-only, and this behaviour contradicts that. Keep track when the first VCPU has run and deny changes to the PMU event filter to prevent this from happening. Signed-off-by: Marc Zyngier <maz@kernel.org> [ Alexandru E: Added commit message, updated ioctl documentation ] Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20220127161759.53553-2-alexandru.elisei@arm.com
2022-01-27 19:17:54 +03:00
struct kvm *kvm = vcpu->kvm;
KVM: arm64: Refuse illegal KVM_ARM_VCPU_PMU_V3 at reset time We accept to configure a PMU when a vcpu is created, even if the HW (or the host) doesn't support it. This results in failures when attributes get set, which is a bit odd as we should have failed the vcpu creation the first place. Move the check to the point where we check the vcpu feature set, and fail early if we cannot support a PMU. This further simplifies the attribute handling. Reviewed-by: Alexandru Elisei <alexandru.elisei@arm.com> Signed-off-by: Marc Zyngier <maz@kernel.org>
2020-11-12 21:13:27 +03:00
if (!kvm_vcpu_has_pmu(vcpu))
KVM: arm64: Refactor PMU attribute error handling The PMU emulation error handling is pretty messy when dealing with attributes. Let's refactor it so that we have less duplication, and that it is easy to extend later on. A functional change is that kvm_arm_pmu_v3_init() used to return -ENXIO when the PMU feature wasn't set. The error is now reported as -ENODEV, matching the documentation. -ENXIO is still returned when the interrupt isn't properly configured. Signed-off-by: Marc Zyngier <maz@kernel.org>
2020-03-12 20:27:36 +03:00
return -ENODEV;
if (vcpu->arch.pmu.created)
return -EBUSY;
KVM: arm64: Keep a per-VM pointer to the default PMU As we are about to allow selection of the PMU exposed to a guest, start by keeping track of the default one instead of only the PMU version. Signed-off-by: Marc Zyngier <maz@kernel.org> Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com> Link: https://lore.kernel.org/r/20220127161759.53553-4-alexandru.elisei@arm.com
2022-01-27 19:17:56 +03:00
mutex_lock(&kvm->lock);
if (!kvm->arch.arm_pmu) {
/* No PMU set, get the default one */
kvm->arch.arm_pmu = kvm_pmu_probe_armpmu();
if (!kvm->arch.arm_pmu) {
mutex_unlock(&kvm->lock);
return -ENODEV;
}
}
mutex_unlock(&kvm->lock);
KVM: arm64: Use event mask matching architecture revision The PMU code suffers from a small defect where we assume that the event number provided by the guest is always 16 bit wide, even if the CPU only implements the ARMv8.0 architecture. This isn't really problematic in the sense that the event number ends up in a system register, cropping it to the right width, but still this needs fixing. In order to make it work, let's probe the version of the PMU that the guest is going to use. This is done by temporarily creating a kernel event and looking at the PMUVer field that has been saved at probe time in the associated arm_pmu structure. This in turn gets saved in the kvm structure, and subsequently used to compute the event mask that gets used throughout the PMU code. Signed-off-by: Marc Zyngier <maz@kernel.org>
2020-03-17 14:11:56 +03:00
arm64: KVM: Add a new vcpu device control group for PMUv3 To configure the virtual PMUv3 overflow interrupt number, we use the vcpu kvm_device ioctl, encapsulating the KVM_ARM_VCPU_PMU_V3_IRQ attribute within the KVM_ARM_VCPU_PMU_V3_CTRL group. After configuring the PMUv3, call the vcpu ioctl with attribute KVM_ARM_VCPU_PMU_V3_INIT to initialize the PMUv3. Signed-off-by: Shannon Zhao <shannon.zhao@linaro.org> Acked-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Andrew Jones <drjones@redhat.com> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2016-01-11 16:35:32 +03:00
switch (attr->attr) {
case KVM_ARM_VCPU_PMU_V3_IRQ: {
int __user *uaddr = (int __user *)(long)attr->addr;
int irq;
KVM: arm64: Do not change the PMU event filter after a VCPU has run Userspace can specify which events a guest is allowed to use with the KVM_ARM_VCPU_PMU_V3_FILTER attribute. The list of allowed events can be identified by a guest from reading the PMCEID{0,1}_EL0 registers. Changing the PMU event filter after a VCPU has run can cause reads of the registers performed before the filter is changed to return different values than reads performed with the new event filter in place. The architecture defines the two registers as read-only, and this behaviour contradicts that. Keep track when the first VCPU has run and deny changes to the PMU event filter to prevent this from happening. Signed-off-by: Marc Zyngier <maz@kernel.org> [ Alexandru E: Added commit message, updated ioctl documentation ] Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20220127161759.53553-2-alexandru.elisei@arm.com
2022-01-27 19:17:54 +03:00
if (!irqchip_in_kernel(kvm))
KVM: arm64: Allow creating the PMU without the in-kernel GIC Since we got support for devices in userspace which allows reporting the PMU overflow output status to userspace, we should actually allow creating the PMU on systems without an in-kernel irqchip, which in turn requires us to slightly clarify error codes for the ABI and move things around for the initialization phase. Signed-off-by: Christoffer Dall <cdall@linaro.org> Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
2017-05-02 14:41:02 +03:00
return -EINVAL;
arm64: KVM: Add a new vcpu device control group for PMUv3 To configure the virtual PMUv3 overflow interrupt number, we use the vcpu kvm_device ioctl, encapsulating the KVM_ARM_VCPU_PMU_V3_IRQ attribute within the KVM_ARM_VCPU_PMU_V3_CTRL group. After configuring the PMUv3, call the vcpu ioctl with attribute KVM_ARM_VCPU_PMU_V3_INIT to initialize the PMUv3. Signed-off-by: Shannon Zhao <shannon.zhao@linaro.org> Acked-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Andrew Jones <drjones@redhat.com> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2016-01-11 16:35:32 +03:00
if (get_user(irq, uaddr))
return -EFAULT;
KVM: arm/arm64: pmu: abstract access to number of SPIs Currently the PMU uses a member of the struct vgic_dist directly, which not only breaks abstraction, but will fail with the new VGIC. Abstract this access in the VGIC header file and refactor the validity check in the PMU code. Signed-off-by: Andre Przywara <andre.przywara@arm.com>
2016-03-07 13:32:29 +03:00
/* The PMU overflow interrupt can be a PPI or a valid SPI. */
KVM: arm/arm64: Don't assume initialized vgic when setting PMU IRQ The PMU IRQ number is set through the VCPU device's KVM_SET_DEVICE_ATTR ioctl handler for the KVM_ARM_VCPU_PMU_V3_IRQ attribute, but there is no enforced or stated requirement that this must happen after initializing the VGIC. As a result, calling vgic_valid_spi() which relies on the nr_spis being set during the VGIC init can incorrectly fail. Introduce irq_is_spi, which determines if an IRQ number is within the SPI range without verifying it against the actual VGIC properties. Signed-off-by: Christoffer Dall <cdall@linaro.org> Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
2017-05-16 20:53:50 +03:00
if (!(irq_is_ppi(irq) || irq_is_spi(irq)))
KVM: arm/arm64: pmu: abstract access to number of SPIs Currently the PMU uses a member of the struct vgic_dist directly, which not only breaks abstraction, but will fail with the new VGIC. Abstract this access in the VGIC header file and refactor the validity check in the PMU code. Signed-off-by: Andre Przywara <andre.przywara@arm.com>
2016-03-07 13:32:29 +03:00
return -EINVAL;
KVM: arm64: Do not change the PMU event filter after a VCPU has run Userspace can specify which events a guest is allowed to use with the KVM_ARM_VCPU_PMU_V3_FILTER attribute. The list of allowed events can be identified by a guest from reading the PMCEID{0,1}_EL0 registers. Changing the PMU event filter after a VCPU has run can cause reads of the registers performed before the filter is changed to return different values than reads performed with the new event filter in place. The architecture defines the two registers as read-only, and this behaviour contradicts that. Keep track when the first VCPU has run and deny changes to the PMU event filter to prevent this from happening. Signed-off-by: Marc Zyngier <maz@kernel.org> [ Alexandru E: Added commit message, updated ioctl documentation ] Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20220127161759.53553-2-alexandru.elisei@arm.com
2022-01-27 19:17:54 +03:00
if (!pmu_irq_is_valid(kvm, irq))
arm64: KVM: Add a new vcpu device control group for PMUv3 To configure the virtual PMUv3 overflow interrupt number, we use the vcpu kvm_device ioctl, encapsulating the KVM_ARM_VCPU_PMU_V3_IRQ attribute within the KVM_ARM_VCPU_PMU_V3_CTRL group. After configuring the PMUv3, call the vcpu ioctl with attribute KVM_ARM_VCPU_PMU_V3_INIT to initialize the PMUv3. Signed-off-by: Shannon Zhao <shannon.zhao@linaro.org> Acked-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Andrew Jones <drjones@redhat.com> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2016-01-11 16:35:32 +03:00
return -EINVAL;
if (kvm_arm_pmu_irq_initialized(vcpu))
return -EBUSY;
kvm_debug("Set kvm ARM PMU irq: %d\n", irq);
vcpu->arch.pmu.irq_num = irq;
return 0;
}
KVM: arm64: Add PMU event filtering infrastructure It can be desirable to expose a PMU to a guest, and yet not want the guest to be able to count some of the implemented events (because this would give information on shared resources, for example. For this, let's extend the PMUv3 device API, and offer a way to setup a bitmap of the allowed events (the default being no bitmap, and thus no filtering). Userspace can thus allow/deny ranges of event. The default policy depends on the "polarity" of the first filter setup (default deny if the filter allows events, and default allow if the filter denies events). This allows to setup exactly what is allowed for a given guest. Note that although the ioctl is per-vcpu, the map of allowed events is global to the VM (it can be setup from any vcpu until the vcpu PMU is initialized). Reviewed-by: Andrew Jones <drjones@redhat.com> Signed-off-by: Marc Zyngier <maz@kernel.org>
2020-02-12 14:31:02 +03:00
case KVM_ARM_VCPU_PMU_V3_FILTER: {
struct kvm_pmu_event_filter __user *uaddr;
struct kvm_pmu_event_filter filter;
int nr_events;
KVM: arm64: Do not change the PMU event filter after a VCPU has run Userspace can specify which events a guest is allowed to use with the KVM_ARM_VCPU_PMU_V3_FILTER attribute. The list of allowed events can be identified by a guest from reading the PMCEID{0,1}_EL0 registers. Changing the PMU event filter after a VCPU has run can cause reads of the registers performed before the filter is changed to return different values than reads performed with the new event filter in place. The architecture defines the two registers as read-only, and this behaviour contradicts that. Keep track when the first VCPU has run and deny changes to the PMU event filter to prevent this from happening. Signed-off-by: Marc Zyngier <maz@kernel.org> [ Alexandru E: Added commit message, updated ioctl documentation ] Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20220127161759.53553-2-alexandru.elisei@arm.com
2022-01-27 19:17:54 +03:00
nr_events = kvm_pmu_event_mask(kvm) + 1;
KVM: arm64: Add PMU event filtering infrastructure It can be desirable to expose a PMU to a guest, and yet not want the guest to be able to count some of the implemented events (because this would give information on shared resources, for example. For this, let's extend the PMUv3 device API, and offer a way to setup a bitmap of the allowed events (the default being no bitmap, and thus no filtering). Userspace can thus allow/deny ranges of event. The default policy depends on the "polarity" of the first filter setup (default deny if the filter allows events, and default allow if the filter denies events). This allows to setup exactly what is allowed for a given guest. Note that although the ioctl is per-vcpu, the map of allowed events is global to the VM (it can be setup from any vcpu until the vcpu PMU is initialized). Reviewed-by: Andrew Jones <drjones@redhat.com> Signed-off-by: Marc Zyngier <maz@kernel.org>
2020-02-12 14:31:02 +03:00
uaddr = (struct kvm_pmu_event_filter __user *)(long)attr->addr;
if (copy_from_user(&filter, uaddr, sizeof(filter)))
return -EFAULT;
if (((u32)filter.base_event + filter.nevents) > nr_events ||
(filter.action != KVM_PMU_EVENT_ALLOW &&
filter.action != KVM_PMU_EVENT_DENY))
return -EINVAL;
KVM: arm64: Do not change the PMU event filter after a VCPU has run Userspace can specify which events a guest is allowed to use with the KVM_ARM_VCPU_PMU_V3_FILTER attribute. The list of allowed events can be identified by a guest from reading the PMCEID{0,1}_EL0 registers. Changing the PMU event filter after a VCPU has run can cause reads of the registers performed before the filter is changed to return different values than reads performed with the new event filter in place. The architecture defines the two registers as read-only, and this behaviour contradicts that. Keep track when the first VCPU has run and deny changes to the PMU event filter to prevent this from happening. Signed-off-by: Marc Zyngier <maz@kernel.org> [ Alexandru E: Added commit message, updated ioctl documentation ] Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20220127161759.53553-2-alexandru.elisei@arm.com
2022-01-27 19:17:54 +03:00
mutex_lock(&kvm->lock);
KVM: arm64: Generalise VM features into a set of flags We currently deal with a set of booleans for VM features, while they could be better represented as set of flags contained in an unsigned long, similarily to what we are doing on the CPU side. Signed-off-by: Marc Zyngier <maz@kernel.org> [Oliver: Flag-ify the 'ran_once' boolean] Signed-off-by: Oliver Upton <oupton@google.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20220311174001.605719-2-oupton@google.com
2022-03-11 20:39:47 +03:00
if (test_bit(KVM_ARCH_FLAG_HAS_RAN_ONCE, &kvm->arch.flags)) {
KVM: arm64: Do not change the PMU event filter after a VCPU has run Userspace can specify which events a guest is allowed to use with the KVM_ARM_VCPU_PMU_V3_FILTER attribute. The list of allowed events can be identified by a guest from reading the PMCEID{0,1}_EL0 registers. Changing the PMU event filter after a VCPU has run can cause reads of the registers performed before the filter is changed to return different values than reads performed with the new event filter in place. The architecture defines the two registers as read-only, and this behaviour contradicts that. Keep track when the first VCPU has run and deny changes to the PMU event filter to prevent this from happening. Signed-off-by: Marc Zyngier <maz@kernel.org> [ Alexandru E: Added commit message, updated ioctl documentation ] Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20220127161759.53553-2-alexandru.elisei@arm.com
2022-01-27 19:17:54 +03:00
mutex_unlock(&kvm->lock);
return -EBUSY;
}
KVM: arm64: Add PMU event filtering infrastructure It can be desirable to expose a PMU to a guest, and yet not want the guest to be able to count some of the implemented events (because this would give information on shared resources, for example. For this, let's extend the PMUv3 device API, and offer a way to setup a bitmap of the allowed events (the default being no bitmap, and thus no filtering). Userspace can thus allow/deny ranges of event. The default policy depends on the "polarity" of the first filter setup (default deny if the filter allows events, and default allow if the filter denies events). This allows to setup exactly what is allowed for a given guest. Note that although the ioctl is per-vcpu, the map of allowed events is global to the VM (it can be setup from any vcpu until the vcpu PMU is initialized). Reviewed-by: Andrew Jones <drjones@redhat.com> Signed-off-by: Marc Zyngier <maz@kernel.org>
2020-02-12 14:31:02 +03:00
KVM: arm64: Do not change the PMU event filter after a VCPU has run Userspace can specify which events a guest is allowed to use with the KVM_ARM_VCPU_PMU_V3_FILTER attribute. The list of allowed events can be identified by a guest from reading the PMCEID{0,1}_EL0 registers. Changing the PMU event filter after a VCPU has run can cause reads of the registers performed before the filter is changed to return different values than reads performed with the new event filter in place. The architecture defines the two registers as read-only, and this behaviour contradicts that. Keep track when the first VCPU has run and deny changes to the PMU event filter to prevent this from happening. Signed-off-by: Marc Zyngier <maz@kernel.org> [ Alexandru E: Added commit message, updated ioctl documentation ] Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20220127161759.53553-2-alexandru.elisei@arm.com
2022-01-27 19:17:54 +03:00
if (!kvm->arch.pmu_filter) {
kvm->arch.pmu_filter = bitmap_alloc(nr_events, GFP_KERNEL_ACCOUNT);
if (!kvm->arch.pmu_filter) {
mutex_unlock(&kvm->lock);
KVM: arm64: Add PMU event filtering infrastructure It can be desirable to expose a PMU to a guest, and yet not want the guest to be able to count some of the implemented events (because this would give information on shared resources, for example. For this, let's extend the PMUv3 device API, and offer a way to setup a bitmap of the allowed events (the default being no bitmap, and thus no filtering). Userspace can thus allow/deny ranges of event. The default policy depends on the "polarity" of the first filter setup (default deny if the filter allows events, and default allow if the filter denies events). This allows to setup exactly what is allowed for a given guest. Note that although the ioctl is per-vcpu, the map of allowed events is global to the VM (it can be setup from any vcpu until the vcpu PMU is initialized). Reviewed-by: Andrew Jones <drjones@redhat.com> Signed-off-by: Marc Zyngier <maz@kernel.org>
2020-02-12 14:31:02 +03:00
return -ENOMEM;
}
/*
* The default depends on the first applied filter.
* If it allows events, the default is to deny.
* Conversely, if the first filter denies a set of
* events, the default is to allow.
*/
if (filter.action == KVM_PMU_EVENT_ALLOW)
KVM: arm64: Do not change the PMU event filter after a VCPU has run Userspace can specify which events a guest is allowed to use with the KVM_ARM_VCPU_PMU_V3_FILTER attribute. The list of allowed events can be identified by a guest from reading the PMCEID{0,1}_EL0 registers. Changing the PMU event filter after a VCPU has run can cause reads of the registers performed before the filter is changed to return different values than reads performed with the new event filter in place. The architecture defines the two registers as read-only, and this behaviour contradicts that. Keep track when the first VCPU has run and deny changes to the PMU event filter to prevent this from happening. Signed-off-by: Marc Zyngier <maz@kernel.org> [ Alexandru E: Added commit message, updated ioctl documentation ] Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20220127161759.53553-2-alexandru.elisei@arm.com
2022-01-27 19:17:54 +03:00
bitmap_zero(kvm->arch.pmu_filter, nr_events);
KVM: arm64: Add PMU event filtering infrastructure It can be desirable to expose a PMU to a guest, and yet not want the guest to be able to count some of the implemented events (because this would give information on shared resources, for example. For this, let's extend the PMUv3 device API, and offer a way to setup a bitmap of the allowed events (the default being no bitmap, and thus no filtering). Userspace can thus allow/deny ranges of event. The default policy depends on the "polarity" of the first filter setup (default deny if the filter allows events, and default allow if the filter denies events). This allows to setup exactly what is allowed for a given guest. Note that although the ioctl is per-vcpu, the map of allowed events is global to the VM (it can be setup from any vcpu until the vcpu PMU is initialized). Reviewed-by: Andrew Jones <drjones@redhat.com> Signed-off-by: Marc Zyngier <maz@kernel.org>
2020-02-12 14:31:02 +03:00
else
KVM: arm64: Do not change the PMU event filter after a VCPU has run Userspace can specify which events a guest is allowed to use with the KVM_ARM_VCPU_PMU_V3_FILTER attribute. The list of allowed events can be identified by a guest from reading the PMCEID{0,1}_EL0 registers. Changing the PMU event filter after a VCPU has run can cause reads of the registers performed before the filter is changed to return different values than reads performed with the new event filter in place. The architecture defines the two registers as read-only, and this behaviour contradicts that. Keep track when the first VCPU has run and deny changes to the PMU event filter to prevent this from happening. Signed-off-by: Marc Zyngier <maz@kernel.org> [ Alexandru E: Added commit message, updated ioctl documentation ] Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20220127161759.53553-2-alexandru.elisei@arm.com
2022-01-27 19:17:54 +03:00
bitmap_fill(kvm->arch.pmu_filter, nr_events);
KVM: arm64: Add PMU event filtering infrastructure It can be desirable to expose a PMU to a guest, and yet not want the guest to be able to count some of the implemented events (because this would give information on shared resources, for example. For this, let's extend the PMUv3 device API, and offer a way to setup a bitmap of the allowed events (the default being no bitmap, and thus no filtering). Userspace can thus allow/deny ranges of event. The default policy depends on the "polarity" of the first filter setup (default deny if the filter allows events, and default allow if the filter denies events). This allows to setup exactly what is allowed for a given guest. Note that although the ioctl is per-vcpu, the map of allowed events is global to the VM (it can be setup from any vcpu until the vcpu PMU is initialized). Reviewed-by: Andrew Jones <drjones@redhat.com> Signed-off-by: Marc Zyngier <maz@kernel.org>
2020-02-12 14:31:02 +03:00
}
if (filter.action == KVM_PMU_EVENT_ALLOW)
KVM: arm64: Do not change the PMU event filter after a VCPU has run Userspace can specify which events a guest is allowed to use with the KVM_ARM_VCPU_PMU_V3_FILTER attribute. The list of allowed events can be identified by a guest from reading the PMCEID{0,1}_EL0 registers. Changing the PMU event filter after a VCPU has run can cause reads of the registers performed before the filter is changed to return different values than reads performed with the new event filter in place. The architecture defines the two registers as read-only, and this behaviour contradicts that. Keep track when the first VCPU has run and deny changes to the PMU event filter to prevent this from happening. Signed-off-by: Marc Zyngier <maz@kernel.org> [ Alexandru E: Added commit message, updated ioctl documentation ] Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20220127161759.53553-2-alexandru.elisei@arm.com
2022-01-27 19:17:54 +03:00
bitmap_set(kvm->arch.pmu_filter, filter.base_event, filter.nevents);
KVM: arm64: Add PMU event filtering infrastructure It can be desirable to expose a PMU to a guest, and yet not want the guest to be able to count some of the implemented events (because this would give information on shared resources, for example. For this, let's extend the PMUv3 device API, and offer a way to setup a bitmap of the allowed events (the default being no bitmap, and thus no filtering). Userspace can thus allow/deny ranges of event. The default policy depends on the "polarity" of the first filter setup (default deny if the filter allows events, and default allow if the filter denies events). This allows to setup exactly what is allowed for a given guest. Note that although the ioctl is per-vcpu, the map of allowed events is global to the VM (it can be setup from any vcpu until the vcpu PMU is initialized). Reviewed-by: Andrew Jones <drjones@redhat.com> Signed-off-by: Marc Zyngier <maz@kernel.org>
2020-02-12 14:31:02 +03:00
else
KVM: arm64: Do not change the PMU event filter after a VCPU has run Userspace can specify which events a guest is allowed to use with the KVM_ARM_VCPU_PMU_V3_FILTER attribute. The list of allowed events can be identified by a guest from reading the PMCEID{0,1}_EL0 registers. Changing the PMU event filter after a VCPU has run can cause reads of the registers performed before the filter is changed to return different values than reads performed with the new event filter in place. The architecture defines the two registers as read-only, and this behaviour contradicts that. Keep track when the first VCPU has run and deny changes to the PMU event filter to prevent this from happening. Signed-off-by: Marc Zyngier <maz@kernel.org> [ Alexandru E: Added commit message, updated ioctl documentation ] Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20220127161759.53553-2-alexandru.elisei@arm.com
2022-01-27 19:17:54 +03:00
bitmap_clear(kvm->arch.pmu_filter, filter.base_event, filter.nevents);
KVM: arm64: Add PMU event filtering infrastructure It can be desirable to expose a PMU to a guest, and yet not want the guest to be able to count some of the implemented events (because this would give information on shared resources, for example. For this, let's extend the PMUv3 device API, and offer a way to setup a bitmap of the allowed events (the default being no bitmap, and thus no filtering). Userspace can thus allow/deny ranges of event. The default policy depends on the "polarity" of the first filter setup (default deny if the filter allows events, and default allow if the filter denies events). This allows to setup exactly what is allowed for a given guest. Note that although the ioctl is per-vcpu, the map of allowed events is global to the VM (it can be setup from any vcpu until the vcpu PMU is initialized). Reviewed-by: Andrew Jones <drjones@redhat.com> Signed-off-by: Marc Zyngier <maz@kernel.org>
2020-02-12 14:31:02 +03:00
KVM: arm64: Do not change the PMU event filter after a VCPU has run Userspace can specify which events a guest is allowed to use with the KVM_ARM_VCPU_PMU_V3_FILTER attribute. The list of allowed events can be identified by a guest from reading the PMCEID{0,1}_EL0 registers. Changing the PMU event filter after a VCPU has run can cause reads of the registers performed before the filter is changed to return different values than reads performed with the new event filter in place. The architecture defines the two registers as read-only, and this behaviour contradicts that. Keep track when the first VCPU has run and deny changes to the PMU event filter to prevent this from happening. Signed-off-by: Marc Zyngier <maz@kernel.org> [ Alexandru E: Added commit message, updated ioctl documentation ] Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20220127161759.53553-2-alexandru.elisei@arm.com
2022-01-27 19:17:54 +03:00
mutex_unlock(&kvm->lock);
KVM: arm64: Add PMU event filtering infrastructure It can be desirable to expose a PMU to a guest, and yet not want the guest to be able to count some of the implemented events (because this would give information on shared resources, for example. For this, let's extend the PMUv3 device API, and offer a way to setup a bitmap of the allowed events (the default being no bitmap, and thus no filtering). Userspace can thus allow/deny ranges of event. The default policy depends on the "polarity" of the first filter setup (default deny if the filter allows events, and default allow if the filter denies events). This allows to setup exactly what is allowed for a given guest. Note that although the ioctl is per-vcpu, the map of allowed events is global to the VM (it can be setup from any vcpu until the vcpu PMU is initialized). Reviewed-by: Andrew Jones <drjones@redhat.com> Signed-off-by: Marc Zyngier <maz@kernel.org>
2020-02-12 14:31:02 +03:00
return 0;
}
KVM: arm64: Add KVM_ARM_VCPU_PMU_V3_SET_PMU attribute When KVM creates an event and there are more than one PMUs present on the system, perf_init_event() will go through the list of available PMUs and will choose the first one that can create the event. The order of the PMUs in this list depends on the probe order, which can change under various circumstances, for example if the order of the PMU nodes change in the DTB or if asynchronous driver probing is enabled on the kernel command line (with the driver_async_probe=armv8-pmu option). Another consequence of this approach is that on heteregeneous systems all virtual machines that KVM creates will use the same PMU. This might cause unexpected behaviour for userspace: when a VCPU is executing on the physical CPU that uses this default PMU, PMU events in the guest work correctly; but when the same VCPU executes on another CPU, PMU events in the guest will suddenly stop counting. Fortunately, perf core allows user to specify on which PMU to create an event by using the perf_event_attr->type field, which is used by perf_init_event() as an index in the radix tree of available PMUs. Add the KVM_ARM_VCPU_PMU_V3_CTRL(KVM_ARM_VCPU_PMU_V3_SET_PMU) VCPU attribute to allow userspace to specify the arm_pmu that KVM will use when creating events for that VCPU. KVM will make no attempt to run the VCPU on the physical CPUs that share the PMU, leaving it up to userspace to manage the VCPU threads' affinity accordingly. To ensure that KVM doesn't expose an asymmetric system to the guest, the PMU set for one VCPU will be used by all other VCPUs. Once a VCPU has run, the PMU cannot be changed in order to avoid changing the list of available events for a VCPU, or to change the semantics of existing events. Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20220127161759.53553-6-alexandru.elisei@arm.com
2022-01-27 19:17:58 +03:00
case KVM_ARM_VCPU_PMU_V3_SET_PMU: {
int __user *uaddr = (int __user *)(long)attr->addr;
int pmu_id;
if (get_user(pmu_id, uaddr))
return -EFAULT;
return kvm_arm_pmu_v3_set_pmu(vcpu, pmu_id);
}
arm64: KVM: Add a new vcpu device control group for PMUv3 To configure the virtual PMUv3 overflow interrupt number, we use the vcpu kvm_device ioctl, encapsulating the KVM_ARM_VCPU_PMU_V3_IRQ attribute within the KVM_ARM_VCPU_PMU_V3_CTRL group. After configuring the PMUv3, call the vcpu ioctl with attribute KVM_ARM_VCPU_PMU_V3_INIT to initialize the PMUv3. Signed-off-by: Shannon Zhao <shannon.zhao@linaro.org> Acked-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Andrew Jones <drjones@redhat.com> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2016-01-11 16:35:32 +03:00
case KVM_ARM_VCPU_PMU_V3_INIT:
return kvm_arm_pmu_v3_init(vcpu);
}
return -ENXIO;
}
int kvm_arm_pmu_v3_get_attr(struct kvm_vcpu *vcpu, struct kvm_device_attr *attr)
{
switch (attr->attr) {
case KVM_ARM_VCPU_PMU_V3_IRQ: {
int __user *uaddr = (int __user *)(long)attr->addr;
int irq;
KVM: arm64: Allow creating the PMU without the in-kernel GIC Since we got support for devices in userspace which allows reporting the PMU overflow output status to userspace, we should actually allow creating the PMU on systems without an in-kernel irqchip, which in turn requires us to slightly clarify error codes for the ABI and move things around for the initialization phase. Signed-off-by: Christoffer Dall <cdall@linaro.org> Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
2017-05-02 14:41:02 +03:00
if (!irqchip_in_kernel(vcpu->kvm))
return -EINVAL;
KVM: arm64: Add kvm_vcpu_has_pmu() helper There are a number of places where we check for the KVM_ARM_VCPU_PMU_V3 feature. Wrap this check into a new kvm_vcpu_has_pmu(), and use it at the existing locations. No functional change. Reviewed-by: Alexandru Elisei <alexandru.elisei@arm.com> Signed-off-by: Marc Zyngier <maz@kernel.org>
2020-11-13 19:39:44 +03:00
if (!kvm_vcpu_has_pmu(vcpu))
arm64: KVM: Add a new vcpu device control group for PMUv3 To configure the virtual PMUv3 overflow interrupt number, we use the vcpu kvm_device ioctl, encapsulating the KVM_ARM_VCPU_PMU_V3_IRQ attribute within the KVM_ARM_VCPU_PMU_V3_CTRL group. After configuring the PMUv3, call the vcpu ioctl with attribute KVM_ARM_VCPU_PMU_V3_INIT to initialize the PMUv3. Signed-off-by: Shannon Zhao <shannon.zhao@linaro.org> Acked-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Andrew Jones <drjones@redhat.com> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2016-01-11 16:35:32 +03:00
return -ENODEV;
if (!kvm_arm_pmu_irq_initialized(vcpu))
return -ENXIO;
irq = vcpu->arch.pmu.irq_num;
return put_user(irq, uaddr);
}
}
return -ENXIO;
}
int kvm_arm_pmu_v3_has_attr(struct kvm_vcpu *vcpu, struct kvm_device_attr *attr)
{
switch (attr->attr) {
case KVM_ARM_VCPU_PMU_V3_IRQ:
case KVM_ARM_VCPU_PMU_V3_INIT:
KVM: arm64: Add PMU event filtering infrastructure It can be desirable to expose a PMU to a guest, and yet not want the guest to be able to count some of the implemented events (because this would give information on shared resources, for example. For this, let's extend the PMUv3 device API, and offer a way to setup a bitmap of the allowed events (the default being no bitmap, and thus no filtering). Userspace can thus allow/deny ranges of event. The default policy depends on the "polarity" of the first filter setup (default deny if the filter allows events, and default allow if the filter denies events). This allows to setup exactly what is allowed for a given guest. Note that although the ioctl is per-vcpu, the map of allowed events is global to the VM (it can be setup from any vcpu until the vcpu PMU is initialized). Reviewed-by: Andrew Jones <drjones@redhat.com> Signed-off-by: Marc Zyngier <maz@kernel.org>
2020-02-12 14:31:02 +03:00
case KVM_ARM_VCPU_PMU_V3_FILTER:
KVM: arm64: Add KVM_ARM_VCPU_PMU_V3_SET_PMU attribute When KVM creates an event and there are more than one PMUs present on the system, perf_init_event() will go through the list of available PMUs and will choose the first one that can create the event. The order of the PMUs in this list depends on the probe order, which can change under various circumstances, for example if the order of the PMU nodes change in the DTB or if asynchronous driver probing is enabled on the kernel command line (with the driver_async_probe=armv8-pmu option). Another consequence of this approach is that on heteregeneous systems all virtual machines that KVM creates will use the same PMU. This might cause unexpected behaviour for userspace: when a VCPU is executing on the physical CPU that uses this default PMU, PMU events in the guest work correctly; but when the same VCPU executes on another CPU, PMU events in the guest will suddenly stop counting. Fortunately, perf core allows user to specify on which PMU to create an event by using the perf_event_attr->type field, which is used by perf_init_event() as an index in the radix tree of available PMUs. Add the KVM_ARM_VCPU_PMU_V3_CTRL(KVM_ARM_VCPU_PMU_V3_SET_PMU) VCPU attribute to allow userspace to specify the arm_pmu that KVM will use when creating events for that VCPU. KVM will make no attempt to run the VCPU on the physical CPUs that share the PMU, leaving it up to userspace to manage the VCPU threads' affinity accordingly. To ensure that KVM doesn't expose an asymmetric system to the guest, the PMU set for one VCPU will be used by all other VCPUs. Once a VCPU has run, the PMU cannot be changed in order to avoid changing the list of available events for a VCPU, or to change the semantics of existing events. Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20220127161759.53553-6-alexandru.elisei@arm.com
2022-01-27 19:17:58 +03:00
case KVM_ARM_VCPU_PMU_V3_SET_PMU:
KVM: arm64: Refuse illegal KVM_ARM_VCPU_PMU_V3 at reset time We accept to configure a PMU when a vcpu is created, even if the HW (or the host) doesn't support it. This results in failures when attributes get set, which is a bit odd as we should have failed the vcpu creation the first place. Move the check to the point where we check the vcpu feature set, and fail early if we cannot support a PMU. This further simplifies the attribute handling. Reviewed-by: Alexandru Elisei <alexandru.elisei@arm.com> Signed-off-by: Marc Zyngier <maz@kernel.org>
2020-11-12 21:13:27 +03:00
if (kvm_vcpu_has_pmu(vcpu))
arm64: KVM: Add a new vcpu device control group for PMUv3 To configure the virtual PMUv3 overflow interrupt number, we use the vcpu kvm_device ioctl, encapsulating the KVM_ARM_VCPU_PMU_V3_IRQ attribute within the KVM_ARM_VCPU_PMU_V3_CTRL group. After configuring the PMUv3, call the vcpu ioctl with attribute KVM_ARM_VCPU_PMU_V3_INIT to initialize the PMUv3. Signed-off-by: Shannon Zhao <shannon.zhao@linaro.org> Acked-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Andrew Jones <drjones@redhat.com> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2016-01-11 16:35:32 +03:00
return 0;
}
return -ENXIO;
}
KVM: arm64: PMU: Move the ID_AA64DFR0_EL1.PMUver limit to VM creation As further patches will enable the selection of a PMU revision from userspace, sample the supported PMU revision at VM creation time, rather than building each time the ID_AA64DFR0_EL1 register is accessed. This shouldn't result in any change in behaviour. Reviewed-by: Reiji Watanabe <reijiw@google.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221113163832.3154370-11-maz@kernel.org
2022-11-13 19:38:26 +03:00
u8 kvm_arm_pmu_get_pmuver_limit(void)
{
u64 tmp;
tmp = read_sanitised_ftr_reg(SYS_ID_AA64DFR0_EL1);
tmp = cpuid_feature_cap_perfmon_field(tmp,
ID_AA64DFR0_EL1_PMUVer_SHIFT,
KVM: arm64: PMU: Allow PMUv3p5 to be exposed to the guest Now that the infrastructure is in place, bump the PMU support up to PMUv3p5. Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221113163832.3154370-15-maz@kernel.org
2022-11-13 19:38:30 +03:00
ID_AA64DFR0_EL1_PMUVer_V3P5);
KVM: arm64: PMU: Move the ID_AA64DFR0_EL1.PMUver limit to VM creation As further patches will enable the selection of a PMU revision from userspace, sample the supported PMU revision at VM creation time, rather than building each time the ID_AA64DFR0_EL1 register is accessed. This shouldn't result in any change in behaviour. Reviewed-by: Reiji Watanabe <reijiw@google.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221113163832.3154370-11-maz@kernel.org
2022-11-13 19:38:26 +03:00
return FIELD_GET(ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_PMUVer), tmp);
}