From 2c7f76b4c42bd5d953bc821e151644434865f999 Mon Sep 17 00:00:00 2001 From: Vitaly Kuznetsov Date: Thu, 18 Mar 2021 15:09:49 +0100 Subject: [PATCH] selftests: kvm: Add basic Hyper-V clocksources tests Introduce a new selftest for Hyper-V clocksources (MSR-based reference TSC and TSC page). As a starting point, test the following: 1) Reference TSC is 1Ghz clock. 2) Reference TSC and TSC page give the same reading. 3) TSC page gets updated upon KVM_SET_CLOCK call. 4) TSC page does not get updated when guest opted for reenlightenment. 5) Disabled TSC page doesn't get updated. Signed-off-by: Vitaly Kuznetsov Message-Id: <20210318140949.1065740-1-vkuznets@redhat.com> [Add a host-side test using TSC + KVM_GET_MSR too. - Paolo] Signed-off-by: Paolo Bonzini --- tools/testing/selftests/kvm/.gitignore | 1 + tools/testing/selftests/kvm/Makefile | 1 + .../selftests/kvm/x86_64/hyperv_clock.c | 260 ++++++++++++++++++ 3 files changed, 262 insertions(+) create mode 100644 tools/testing/selftests/kvm/x86_64/hyperv_clock.c diff --git a/tools/testing/selftests/kvm/.gitignore b/tools/testing/selftests/kvm/.gitignore index 32b87cc77c8e..22be05c55f13 100644 --- a/tools/testing/selftests/kvm/.gitignore +++ b/tools/testing/selftests/kvm/.gitignore @@ -9,6 +9,7 @@ /x86_64/evmcs_test /x86_64/get_cpuid_test /x86_64/kvm_pv_test +/x86_64/hyperv_clock /x86_64/hyperv_cpuid /x86_64/mmio_warning_test /x86_64/platform_info_test diff --git a/tools/testing/selftests/kvm/Makefile b/tools/testing/selftests/kvm/Makefile index a6d61f451f88..c3672e9087d3 100644 --- a/tools/testing/selftests/kvm/Makefile +++ b/tools/testing/selftests/kvm/Makefile @@ -41,6 +41,7 @@ LIBKVM_s390x = lib/s390x/processor.c lib/s390x/ucall.c lib/s390x/diag318_test_ha TEST_GEN_PROGS_x86_64 = x86_64/cr4_cpuid_sync_test TEST_GEN_PROGS_x86_64 += x86_64/evmcs_test TEST_GEN_PROGS_x86_64 += x86_64/get_cpuid_test +TEST_GEN_PROGS_x86_64 += x86_64/hyperv_clock TEST_GEN_PROGS_x86_64 += x86_64/hyperv_cpuid TEST_GEN_PROGS_x86_64 += x86_64/kvm_pv_test TEST_GEN_PROGS_x86_64 += x86_64/mmio_warning_test diff --git a/tools/testing/selftests/kvm/x86_64/hyperv_clock.c b/tools/testing/selftests/kvm/x86_64/hyperv_clock.c new file mode 100644 index 000000000000..ffbc4555c6e2 --- /dev/null +++ b/tools/testing/selftests/kvm/x86_64/hyperv_clock.c @@ -0,0 +1,260 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (C) 2021, Red Hat, Inc. + * + * Tests for Hyper-V clocksources + */ +#include "test_util.h" +#include "kvm_util.h" +#include "processor.h" + +struct ms_hyperv_tsc_page { + volatile u32 tsc_sequence; + u32 reserved1; + volatile u64 tsc_scale; + volatile s64 tsc_offset; +} __packed; + +#define HV_X64_MSR_GUEST_OS_ID 0x40000000 +#define HV_X64_MSR_TIME_REF_COUNT 0x40000020 +#define HV_X64_MSR_REFERENCE_TSC 0x40000021 +#define HV_X64_MSR_TSC_FREQUENCY 0x40000022 +#define HV_X64_MSR_REENLIGHTENMENT_CONTROL 0x40000106 +#define HV_X64_MSR_TSC_EMULATION_CONTROL 0x40000107 + +/* Simplified mul_u64_u64_shr() */ +static inline u64 mul_u64_u64_shr64(u64 a, u64 b) +{ + union { + u64 ll; + struct { + u32 low, high; + } l; + } rm, rn, rh, a0, b0; + u64 c; + + a0.ll = a; + b0.ll = b; + + rm.ll = (u64)a0.l.low * b0.l.high; + rn.ll = (u64)a0.l.high * b0.l.low; + rh.ll = (u64)a0.l.high * b0.l.high; + + rh.l.low = c = rm.l.high + rn.l.high + rh.l.low; + rh.l.high = (c >> 32) + rh.l.high; + + return rh.ll; +} + +static inline void nop_loop(void) +{ + int i; + + for (i = 0; i < 1000000; i++) + asm volatile("nop"); +} + +static inline void check_tsc_msr_rdtsc(void) +{ + u64 tsc_freq, r1, r2, t1, t2; + s64 delta_ns; + + tsc_freq = rdmsr(HV_X64_MSR_TSC_FREQUENCY); + GUEST_ASSERT(tsc_freq > 0); + + /* First, check MSR-based clocksource */ + r1 = rdtsc(); + t1 = rdmsr(HV_X64_MSR_TIME_REF_COUNT); + nop_loop(); + r2 = rdtsc(); + t2 = rdmsr(HV_X64_MSR_TIME_REF_COUNT); + + GUEST_ASSERT(r2 > r1 && t2 > t1); + + /* HV_X64_MSR_TIME_REF_COUNT is in 100ns */ + delta_ns = ((t2 - t1) * 100) - ((r2 - r1) * 1000000000 / tsc_freq); + if (delta_ns < 0) + delta_ns = -delta_ns; + + /* 1% tolerance */ + GUEST_ASSERT(delta_ns * 100 < (t2 - t1) * 100); +} + +static inline void check_tsc_msr_tsc_page(struct ms_hyperv_tsc_page *tsc_page) +{ + u64 r1, r2, t1, t2; + + /* Compare TSC page clocksource with HV_X64_MSR_TIME_REF_COUNT */ + t1 = mul_u64_u64_shr64(rdtsc(), tsc_page->tsc_scale) + tsc_page->tsc_offset; + r1 = rdmsr(HV_X64_MSR_TIME_REF_COUNT); + + /* 10 ms tolerance */ + GUEST_ASSERT(r1 >= t1 && r1 - t1 < 100000); + nop_loop(); + + t2 = mul_u64_u64_shr64(rdtsc(), tsc_page->tsc_scale) + tsc_page->tsc_offset; + r2 = rdmsr(HV_X64_MSR_TIME_REF_COUNT); + GUEST_ASSERT(r2 >= t1 && r2 - t2 < 100000); +} + +static void guest_main(struct ms_hyperv_tsc_page *tsc_page, vm_paddr_t tsc_page_gpa) +{ + u64 tsc_scale, tsc_offset; + + /* Set Guest OS id to enable Hyper-V emulation */ + GUEST_SYNC(1); + wrmsr(HV_X64_MSR_GUEST_OS_ID, (u64)0x8100 << 48); + GUEST_SYNC(2); + + check_tsc_msr_rdtsc(); + + GUEST_SYNC(3); + + /* Set up TSC page is disabled state, check that it's clean */ + wrmsr(HV_X64_MSR_REFERENCE_TSC, tsc_page_gpa); + GUEST_ASSERT(tsc_page->tsc_sequence == 0); + GUEST_ASSERT(tsc_page->tsc_scale == 0); + GUEST_ASSERT(tsc_page->tsc_offset == 0); + + GUEST_SYNC(4); + + /* Set up TSC page is enabled state */ + wrmsr(HV_X64_MSR_REFERENCE_TSC, tsc_page_gpa | 0x1); + GUEST_ASSERT(tsc_page->tsc_sequence != 0); + + GUEST_SYNC(5); + + check_tsc_msr_tsc_page(tsc_page); + + GUEST_SYNC(6); + + tsc_offset = tsc_page->tsc_offset; + /* Call KVM_SET_CLOCK from userspace, check that TSC page was updated */ + GUEST_SYNC(7); + GUEST_ASSERT(tsc_page->tsc_offset != tsc_offset); + + nop_loop(); + + /* + * Enable Re-enlightenment and check that TSC page stays constant across + * KVM_SET_CLOCK. + */ + wrmsr(HV_X64_MSR_REENLIGHTENMENT_CONTROL, 0x1 << 16 | 0xff); + wrmsr(HV_X64_MSR_TSC_EMULATION_CONTROL, 0x1); + tsc_offset = tsc_page->tsc_offset; + tsc_scale = tsc_page->tsc_scale; + GUEST_SYNC(8); + GUEST_ASSERT(tsc_page->tsc_offset == tsc_offset); + GUEST_ASSERT(tsc_page->tsc_scale == tsc_scale); + + GUEST_SYNC(9); + + check_tsc_msr_tsc_page(tsc_page); + + /* + * Disable re-enlightenment and TSC page, check that KVM doesn't update + * it anymore. + */ + wrmsr(HV_X64_MSR_REENLIGHTENMENT_CONTROL, 0); + wrmsr(HV_X64_MSR_TSC_EMULATION_CONTROL, 0); + wrmsr(HV_X64_MSR_REFERENCE_TSC, 0); + memset(tsc_page, 0, sizeof(*tsc_page)); + + GUEST_SYNC(10); + GUEST_ASSERT(tsc_page->tsc_sequence == 0); + GUEST_ASSERT(tsc_page->tsc_offset == 0); + GUEST_ASSERT(tsc_page->tsc_scale == 0); + + GUEST_DONE(); +} + +#define VCPU_ID 0 + +static void host_check_tsc_msr_rdtsc(struct kvm_vm *vm) +{ + u64 tsc_freq, r1, r2, t1, t2; + s64 delta_ns; + + tsc_freq = vcpu_get_msr(vm, VCPU_ID, HV_X64_MSR_TSC_FREQUENCY); + TEST_ASSERT(tsc_freq > 0, "TSC frequency must be nonzero"); + + /* First, check MSR-based clocksource */ + r1 = rdtsc(); + t1 = vcpu_get_msr(vm, VCPU_ID, HV_X64_MSR_TIME_REF_COUNT); + nop_loop(); + r2 = rdtsc(); + t2 = vcpu_get_msr(vm, VCPU_ID, HV_X64_MSR_TIME_REF_COUNT); + + TEST_ASSERT(t2 > t1, "Time reference MSR is not monotonic (%ld <= %ld)", t1, t2); + + /* HV_X64_MSR_TIME_REF_COUNT is in 100ns */ + delta_ns = ((t2 - t1) * 100) - ((r2 - r1) * 1000000000 / tsc_freq); + if (delta_ns < 0) + delta_ns = -delta_ns; + + /* 1% tolerance */ + TEST_ASSERT(delta_ns * 100 < (t2 - t1) * 100, + "Elapsed time does not match (MSR=%ld, TSC=%ld)", + (t2 - t1) * 100, (r2 - r1) * 1000000000 / tsc_freq); +} + +int main(void) +{ + struct kvm_vm *vm; + struct kvm_run *run; + struct ucall uc; + vm_vaddr_t tsc_page_gva; + int stage; + + vm = vm_create_default(VCPU_ID, 0, guest_main); + run = vcpu_state(vm, VCPU_ID); + + vcpu_set_hv_cpuid(vm, VCPU_ID); + + tsc_page_gva = vm_vaddr_alloc(vm, getpagesize(), 0x10000, 0, 0); + memset(addr_gpa2hva(vm, tsc_page_gva), 0x0, getpagesize()); + TEST_ASSERT((addr_gva2gpa(vm, tsc_page_gva) & (getpagesize() - 1)) == 0, + "TSC page has to be page aligned\n"); + vcpu_args_set(vm, VCPU_ID, 2, tsc_page_gva, addr_gva2gpa(vm, tsc_page_gva)); + + host_check_tsc_msr_rdtsc(vm); + + for (stage = 1;; stage++) { + _vcpu_run(vm, VCPU_ID); + TEST_ASSERT(run->exit_reason == KVM_EXIT_IO, + "Stage %d: unexpected exit reason: %u (%s),\n", + stage, run->exit_reason, + exit_reason_str(run->exit_reason)); + + switch (get_ucall(vm, VCPU_ID, &uc)) { + case UCALL_ABORT: + TEST_FAIL("%s at %s:%ld", (const char *)uc.args[0], + __FILE__, uc.args[1]); + /* NOT REACHED */ + case UCALL_SYNC: + break; + case UCALL_DONE: + /* Keep in sync with guest_main() */ + TEST_ASSERT(stage == 11, "Testing ended prematurely, stage %d\n", + stage); + goto out; + default: + TEST_FAIL("Unknown ucall %lu", uc.cmd); + } + + TEST_ASSERT(!strcmp((const char *)uc.args[0], "hello") && + uc.args[1] == stage, + "Stage %d: Unexpected register values vmexit, got %lx", + stage, (ulong)uc.args[1]); + + /* Reset kvmclock triggering TSC page update */ + if (stage == 7 || stage == 8 || stage == 10) { + struct kvm_clock_data clock = {0}; + + vm_ioctl(vm, KVM_SET_CLOCK, &clock); + } + } + +out: + kvm_vm_free(vm); +}