The following issue is observed with CONFIG_DEBUG_PREEMPT when KVM loads:
KVM: vmx: using Hyper-V Enlightened VMCS
BUG: using smp_processor_id() in preemptible [00000000] code: systemd-udevd/488
caller is set_hv_tscchange_cb+0x16/0x80
CPU: 1 PID: 488 Comm: systemd-udevd Not tainted 5.15.0-rc5+ #396
Hardware name: Microsoft Corporation Virtual Machine/Virtual Machine, BIOS Hyper-V UEFI Release v4.0 12/17/2019
Call Trace:
dump_stack_lvl+0x6a/0x9a
check_preemption_disabled+0xde/0xe0
? kvm_gen_update_masterclock+0xd0/0xd0 [kvm]
set_hv_tscchange_cb+0x16/0x80
kvm_arch_init+0x23f/0x290 [kvm]
kvm_init+0x30/0x310 [kvm]
vmx_init+0xaf/0x134 [kvm_intel]
...
set_hv_tscchange_cb() can get preempted in between acquiring
smp_processor_id() and writing to HV_X64_MSR_REENLIGHTENMENT_CONTROL. This
is not an issue by itself: HV_X64_MSR_REENLIGHTENMENT_CONTROL is a
partition-wide MSR and it doesn't matter which particular CPU will be
used to receive reenlightenment notifications. The only real problem can
(in theory) be observed if the CPU whose id was acquired with
smp_processor_id() goes offline before we manage to write to the MSR,
the logic in hv_cpu_die() won't be able to reassign it correctly.
Reported-by: Michael Kelley <mikelley@microsoft.com>
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Link: https://lore.kernel.org/r/20211012155005.1613352-1-vkuznets@redhat.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
Clean up the following includecheck warning:
./arch/x86/hyperv/ivm.c: linux/bitfield.h is included more than once.
./arch/x86/hyperv/ivm.c: linux/types.h is included more than once.
Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Signed-off-by: Jiapeng Chong <jiapeng.chong@linux.alibaba.com>
Link: https://lore.kernel.org/r/1635325022-99889-1-git-send-email-jiapeng.chong@linux.alibaba.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
Fix following checkinclude.pl warning:
./arch/x86/hyperv/hv_init.c: linux/io.h is included more than once.
The include is in line 13. Remove the duplicated here.
Signed-off-by: Wan Jiabing <wanjiabing@vivo.com>
Link: https://lore.kernel.org/r/20211026113249.30481-1-wanjiabing@vivo.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
hyperv provides ghcb hvcall to handle VMBus
HVCALL_SIGNAL_EVENT and HVCALL_POST_MESSAGE
msg in SNP Isolation VM. Add such support.
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Signed-off-by: Tianyu Lan <Tianyu.Lan@microsoft.com>
Link: https://lore.kernel.org/r/20211025122116.264793-8-ltykernel@gmail.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
Hyperv provides GHCB protocol to write Synthetic Interrupt
Controller MSR registers in Isolation VM with AMD SEV SNP
and these registers are emulated by hypervisor directly.
Hyperv requires to write SINTx MSR registers twice. First
writes MSR via GHCB page to communicate with hypervisor
and then writes wrmsr instruction to talk with paravisor
which runs in VMPL0. Guest OS ID MSR also needs to be set
via GHCB page.
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Signed-off-by: Tianyu Lan <Tianyu.Lan@microsoft.com>
Link: https://lore.kernel.org/r/20211025122116.264793-7-ltykernel@gmail.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
Add new hvcall guest address host visibility support to mark
memory visible to host. Call it inside set_memory_decrypted
/encrypted(). Add HYPERVISOR feature check in the
hv_is_isolation_supported() to optimize in non-virtualization
environment.
Acked-by: Dave Hansen <dave.hansen@intel.com>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Signed-off-by: Tianyu Lan <Tianyu.Lan@microsoft.com>
Link: https://lore.kernel.org/r/20211025122116.264793-4-ltykernel@gmail.com
[ wei: fix conflicts with tip ]
Signed-off-by: Wei Liu <wei.liu@kernel.org>
Hyperv exposes GHCB page via SEV ES GHCB MSR for SNP guest
to communicate with hypervisor. Map GHCB page for all
cpus to read/write MSR register and submit hvcall request
via ghcb page.
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Signed-off-by: Tianyu Lan <Tianyu.Lan@microsoft.com>
Link: https://lore.kernel.org/r/20211025122116.264793-2-ltykernel@gmail.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
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Merge tag 'hyperv-fixes-signed-20211007' of git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux
Pull hyperv fixes from Wei Liu:
- Replace uuid.h with types.h in a header (Andy Shevchenko)
- Avoid sleeping in atomic context in PCI driver (Long Li)
- Avoid sending IPI to self when it shouldn't (Vitaly Kuznetsov)
* tag 'hyperv-fixes-signed-20211007' of git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux:
x86/hyperv: Avoid erroneously sending IPI to 'self'
hyper-v: Replace uuid.h with types.h
PCI: hv: Fix sleep while in non-sleep context when removing child devices from the bus
__send_ipi_mask_ex() uses an optimization: when the target CPU mask is
equal to 'cpu_present_mask' it uses 'HV_GENERIC_SET_ALL' format to avoid
converting the specified cpumask to VP_SET. This case was overlooked when
'exclude_self' parameter was added. As the result, a spurious IPI to
'self' can be send.
Reported-by: Thomas Gleixner <tglx@linutronix.de>
Fixes: dfb5c1e12c ("x86/hyperv: remove on-stack cpumask from hv_send_ipi_mask_allbutself")
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Link: https://lore.kernel.org/r/20211006125016.941616-1-vkuznets@redhat.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
It is not a good practice to allocate a cpumask on stack, given it may
consume up to 1 kilobytes of stack space if the kernel is configured to
have 8192 cpus.
The internal helper functions __send_ipi_mask{,_ex} need to loop over
the provided mask anyway, so it is not too difficult to skip `self'
there. We can thus do away with the on-stack cpumask in
hv_send_ipi_mask_allbutself.
Adjust call sites of __send_ipi_mask as needed.
Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Suggested-by: Michael Kelley <mikelley@microsoft.com>
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Fixes: 68bb7bfb79 ("X86/Hyper-V: Enable IPI enlightenments")
Signed-off-by: Wei Liu <wei.liu@kernel.org>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Link: https://lore.kernel.org/r/20210910185714.299411-3-wei.liu@kernel.org
For root partition the VP assist pages are pre-determined by the
hypervisor. The root kernel is not allowed to change them to
different locations. And thus, we are getting below stack as in
current implementation root is trying to perform write to specific
MSR.
[ 2.778197] unchecked MSR access error: WRMSR to 0x40000073 (tried to write 0x0000000145ac5001) at rIP: 0xffffffff810c1084 (native_write_msr+0x4/0x30)
[ 2.784867] Call Trace:
[ 2.791507] hv_cpu_init+0xf1/0x1c0
[ 2.798144] ? hyperv_report_panic+0xd0/0xd0
[ 2.804806] cpuhp_invoke_callback+0x11a/0x440
[ 2.811465] ? hv_resume+0x90/0x90
[ 2.818137] cpuhp_issue_call+0x126/0x130
[ 2.824782] __cpuhp_setup_state_cpuslocked+0x102/0x2b0
[ 2.831427] ? hyperv_report_panic+0xd0/0xd0
[ 2.838075] ? hyperv_report_panic+0xd0/0xd0
[ 2.844723] ? hv_resume+0x90/0x90
[ 2.851375] __cpuhp_setup_state+0x3d/0x90
[ 2.858030] hyperv_init+0x14e/0x410
[ 2.864689] ? enable_IR_x2apic+0x190/0x1a0
[ 2.871349] apic_intr_mode_init+0x8b/0x100
[ 2.878017] x86_late_time_init+0x20/0x30
[ 2.884675] start_kernel+0x459/0x4fb
[ 2.891329] secondary_startup_64_no_verify+0xb0/0xbb
Since the hypervisor already provides the VP assist pages for root
partition, we need to memremap the memory from hypervisor for root
kernel to use. The mapping is done in hv_cpu_init during bringup and is
unmapped in hv_cpu_die during teardown.
Signed-off-by: Praveen Kumar <kumarpraveen@linux.microsoft.com>
Reviewed-by: Sunil Muthuswamy <sunilmut@microsoft.com>
Link: https://lore.kernel.org/r/20210731120519.17154-1-kumarpraveen@linux.microsoft.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
The check for whether hibernation is possible, and the enabling of
Hyper-V panic notification during kexec, are both architecture neutral.
Move the code from under arch/x86 and into drivers/hv/hv_common.c where
it can also be used for ARM64.
No functional change.
Signed-off-by: Michael Kelley <mikelley@microsoft.com>
Link: https://lore.kernel.org/r/1626287687-2045-4-git-send-email-mikelley@microsoft.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
Architecture independent Hyper-V code calls various arch-specific handlers
when needed. To aid in supporting multiple architectures, provide weak
defaults that can be overridden by arch-specific implementations where
appropriate. But when arch-specific overrides aren't needed or haven't
been implemented yet for a particular architecture, these stubs reduce
the amount of clutter under arch/.
No functional change.
Signed-off-by: Michael Kelley <mikelley@microsoft.com>
Link: https://lore.kernel.org/r/1626287687-2045-3-git-send-email-mikelley@microsoft.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
The code to allocate and initialize the hv_vp_index array is
architecture neutral. Similarly, the code to allocate and
populate the hypercall input and output arg pages is architecture
neutral. Move both sets of code out from arch/x86 and into
utility functions in drivers/hv/hv_common.c that can be shared
by Hyper-V initialization on ARM64.
No functional changes. However, the allocation of the hypercall
input and output arg pages is done differently so that the
size is always the Hyper-V page size, even if not the same as
the guest page size (such as with ARM64's 64K page size).
Signed-off-by: Michael Kelley <mikelley@microsoft.com>
Link: https://lore.kernel.org/r/1626287687-2045-2-git-send-email-mikelley@microsoft.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
The extended capability query code is currently under arch/x86, but it
is architecture neutral, and is used by arch neutral code in the Hyper-V
balloon driver. Hence the balloon driver fails to build on other
architectures.
Fix by moving the ext cap code out from arch/x86. Because it is also
called from built-in architecture specific code, it can't be in a module,
so the Makefile treats as built-in even when CONFIG_HYPERV is "m". Also
drivers/Makefile is tweaked because this is the first occurrence of a
Hyper-V file that is built-in even when CONFIG_HYPERV is "m".
While here, update the hypercall status check to use the new helper
function instead of open coding. No functional change.
Signed-off-by: Michael Kelley <mikelley@microsoft.com>
Reviewed-by: Sunil Muthuswamy <sunilmut@microsoft.com>
Link: https://lore.kernel.org/r/1622669804-2016-1-git-send-email-mikelley@microsoft.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
- Implement concurrent TLB flushes, which overlaps the local TLB flush with the
remote TLB flush. In testing this improved sysbench performance measurably by
a couple of percentage points, especially if TLB-heavy security mitigations
are active.
- Further micro-optimizations to improve the performance of TLB flushes.
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'x86-mm-2021-04-29' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 tlb updates from Ingo Molnar:
"The x86 MM changes in this cycle were:
- Implement concurrent TLB flushes, which overlaps the local TLB
flush with the remote TLB flush.
In testing this improved sysbench performance measurably by a
couple of percentage points, especially if TLB-heavy security
mitigations are active.
- Further micro-optimizations to improve the performance of TLB
flushes"
* tag 'x86-mm-2021-04-29' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
smp: Micro-optimize smp_call_function_many_cond()
smp: Inline on_each_cpu_cond() and on_each_cpu()
x86/mm/tlb: Remove unnecessary uses of the inline keyword
cpumask: Mark functions as pure
x86/mm/tlb: Do not make is_lazy dirty for no reason
x86/mm/tlb: Privatize cpu_tlbstate
x86/mm/tlb: Flush remote and local TLBs concurrently
x86/mm/tlb: Open-code on_each_cpu_cond_mask() for tlb_is_not_lazy()
x86/mm/tlb: Unify flush_tlb_func_local() and flush_tlb_func_remote()
smp: Run functions concurrently in smp_call_function_many_cond()
There is not a consistent pattern for checking Hyper-V hypercall status.
Existing code uses a number of variants. The variants work, but a consistent
pattern would improve the readability of the code, and be more conformant
to what the Hyper-V TLFS says about hypercall status.
Implemented new helper functions hv_result(), hv_result_success(), and
hv_repcomp(). Changed the places where hv_do_hypercall() and related variants
are used to use the helper functions.
Signed-off-by: Joseph Salisbury <joseph.salisbury@microsoft.com>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Link: https://lore.kernel.org/r/1618620183-9967-2-git-send-email-joseph.salisbury@linux.microsoft.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
Linux has support for free page reporting now (36e66c554b) for
virtualized environment. On Hyper-V when virtually backed VMs are
configured, Hyper-V will advertise cold memory discard capability,
when supported. This patch adds the support to hook into the free
page reporting infrastructure and leverage the Hyper-V cold memory
discard hint hypercall to report/free these pages back to the host.
Signed-off-by: Sunil Muthuswamy <sunilmut@microsoft.com>
Tested-by: Matheus Castello <matheus@castello.eng.br>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Tested-by: Nathan Chancellor <nathan@kernel.org>
Link: https://lore.kernel.org/r/SN4PR2101MB0880121FA4E2FEC67F35C1DCC0649@SN4PR2101MB0880.namprd21.prod.outlook.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
Fixes the following W=1 kernel build warning(s):
arch/x86/hyperv/hv_apic.c:58:15: warning: variable ‘hi’ set but not used [-Wunused-but-set-variable]
Compiled with CONFIG_HYPERV enabled:
make allmodconfig ARCH=x86_64 CROSS_COMPILE=x86_64-linux-gnu-
make W=1 arch/x86/hyperv/hv_apic.o ARCH=x86_64 CROSS_COMPILE=x86_64-linux-gnu-
HV_X64_MSR_EOI occupies bit 31:0 and HV_X64_MSR_TPR occupies bit 7:0,
which means the higher 32 bits are not really used. Cast the variable hi
to void to silence this warning.
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Xu Yihang <xuyihang@huawei.com>
Link: https://lore.kernel.org/r/20210323025013.191533-1-xuyihang@huawei.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
Fixes the following W=1 kernel build warning(s):
arch/x86/hyperv/hv_spinlock.c:28:16: warning: variable ‘msr_val’ set but not used [-Wunused-but-set-variable]
unsigned long msr_val;
As Hypervisor Top-Level Functional Specification states in chapter 7.5
Virtual Processor Idle Sleep State, "A partition which possesses the
AccessGuestIdleMsr privilege (refer to section 4.2.2) may trigger entry
into the virtual processor idle sleep state through a read to the
hypervisor-defined MSR HV_X64_MSR_GUEST_IDLE".
That means only a read of the MSR is necessary. The returned value
msr_val is not used. Cast it to void to silence this warning.
Reference:
https://docs.microsoft.com/en-us/virtualization/hyper-v-on-windows/reference/tlfs
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Xu Yihang <xuyihang@huawei.com>
Link: https://lore.kernel.org/r/20210323024302.174434-1-xuyihang@huawei.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
Fix ~144 single-word typos in arch/x86/ code comments.
Doing this in a single commit should reduce the churn.
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: linux-kernel@vger.kernel.org
STIMER0 interrupts are most naturally modeled as per-cpu IRQs. But
because x86/x64 doesn't have per-cpu IRQs, the core STIMER0 interrupt
handling machinery is done in code under arch/x86 and Linux IRQs are
not used. Adding support for ARM64 means adding equivalent code
using per-cpu IRQs under arch/arm64.
A better model is to treat per-cpu IRQs as the normal path (which it is
for modern architectures), and the x86/x64 path as the exception. Do this
by incorporating standard Linux per-cpu IRQ allocation into the main
SITMER0 driver code, and bypass it in the x86/x64 exception case. For
x86/x64, special case code is retained under arch/x86, but no STIMER0
interrupt handling code is needed under arch/arm64.
No functional change.
Signed-off-by: Michael Kelley <mikelley@microsoft.com>
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://lore.kernel.org/r/1614721102-2241-11-git-send-email-mikelley@microsoft.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
With the new Hyper-V MSR set function, hyperv_report_panic_msg() can be
architecture neutral, so move it out from under arch/x86 and merge into
hv_kmsg_dump(). This move also avoids needing a separate implementation
under arch/arm64.
No functional change.
Signed-off-by: Michael Kelley <mikelley@microsoft.com>
Reviewed-by: Boqun Feng <boqun.feng@gmail.com>
Link: https://lore.kernel.org/r/1614721102-2241-5-git-send-email-mikelley@microsoft.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
Current code defines a separate get and set macro for each Hyper-V
synthetic MSR used by the VMbus driver. Furthermore, the get macro
can't be converted to a standard function because the second argument
is modified in place, which is somewhat bad form.
Redo this by providing a single get and a single set function that
take a parameter specifying the MSR to be operated on. Fixup usage
of the get function. Calling locations are no more complex than before,
but the code under arch/x86 and the upcoming code under arch/arm64
is significantly simplified.
Also standardize the names of Hyper-V synthetic MSRs that are
architecture neutral. But keep the old x86-specific names as aliases
that can be removed later when all references (particularly in KVM
code) have been cleaned up in a separate patch series.
No functional change.
Signed-off-by: Michael Kelley <mikelley@microsoft.com>
Reviewed-by: Boqun Feng <boqun.feng@gmail.com>
Link: https://lore.kernel.org/r/1614721102-2241-4-git-send-email-mikelley@microsoft.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
The Hyper-V page allocator functions are implemented in an architecture
neutral way. Move them into the architecture neutral VMbus module so
a separate implementation for ARM64 is not needed.
No functional change.
Signed-off-by: Michael Kelley <mikelley@microsoft.com>
Reviewed-by: Boqun Feng <boqun.feng@gmail.com>
Link: https://lore.kernel.org/r/1614721102-2241-2-git-send-email-mikelley@microsoft.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
To improve TLB shootdown performance, flush the remote and local TLBs
concurrently. Introduce flush_tlb_multi() that does so. Introduce
paravirtual versions of flush_tlb_multi() for KVM, Xen and hyper-v (Xen
and hyper-v are only compile-tested).
While the updated smp infrastructure is capable of running a function on
a single local core, it is not optimized for this case. The multiple
function calls and the indirect branch introduce some overhead, and
might make local TLB flushes slower than they were before the recent
changes.
Before calling the SMP infrastructure, check if only a local TLB flush
is needed to restore the lost performance in this common case. This
requires to check mm_cpumask() one more time, but unless this mask is
updated very frequently, this should impact performance negatively.
Signed-off-by: Nadav Amit <namit@vmware.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Michael Kelley <mikelley@microsoft.com> # Hyper-v parts
Reviewed-by: Juergen Gross <jgross@suse.com> # Xen and paravirt parts
Reviewed-by: Dave Hansen <dave.hansen@linux.intel.com>
Link: https://lore.kernel.org/r/20210220231712.2475218-5-namit@vmware.com
Just like MSI/MSI-X, IO-APIC interrupts are remapped by Microsoft
Hypervisor when Linux runs as the root partition. Implement an IRQ
domain to handle mapping and unmapping of IO-APIC interrupts.
Signed-off-by: Wei Liu <wei.liu@kernel.org>
Acked-by: Joerg Roedel <joro@8bytes.org>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Link: https://lore.kernel.org/r/20210203150435.27941-17-wei.liu@kernel.org
When Linux runs as the root partition on Microsoft Hypervisor, its
interrupts are remapped. Linux will need to explicitly map and unmap
interrupts for hardware.
Implement an MSI domain to issue the correct hypercalls. And initialize
this irq domain as the default MSI irq domain.
Signed-off-by: Sunil Muthuswamy <sunilmut@microsoft.com>
Co-Developed-by: Sunil Muthuswamy <sunilmut@microsoft.com>
Signed-off-by: Wei Liu <wei.liu@kernel.org>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Link: https://lore.kernel.org/r/20210203150435.27941-16-wei.liu@kernel.org
They are used to deposit pages into Microsoft Hypervisor and bring up
logical and virtual processors.
Signed-off-by: Lillian Grassin-Drake <ligrassi@microsoft.com>
Signed-off-by: Sunil Muthuswamy <sunilmut@microsoft.com>
Signed-off-by: Nuno Das Neves <nunodasneves@linux.microsoft.com>
Co-Developed-by: Lillian Grassin-Drake <ligrassi@microsoft.com>
Co-Developed-by: Sunil Muthuswamy <sunilmut@microsoft.com>
Co-Developed-by: Nuno Das Neves <nunodasneves@linux.microsoft.com>
Signed-off-by: Wei Liu <wei.liu@kernel.org>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Link: https://lore.kernel.org/r/20210203150435.27941-10-wei.liu@kernel.org
When Linux is running as the root partition, the hypercall page will
have already been setup by Hyper-V. Copy the content over to the
allocated page.
Add checks to hv_suspend & co to bail early because they are not
supported in this setup yet.
Signed-off-by: Lillian Grassin-Drake <ligrassi@microsoft.com>
Signed-off-by: Sunil Muthuswamy <sunilmut@microsoft.com>
Signed-off-by: Nuno Das Neves <nunodasneves@linux.microsoft.com>
Co-Developed-by: Lillian Grassin-Drake <ligrassi@microsoft.com>
Co-Developed-by: Sunil Muthuswamy <sunilmut@microsoft.com>
Co-Developed-by: Nuno Das Neves <nunodasneves@linux.microsoft.com>
Signed-off-by: Wei Liu <wei.liu@kernel.org>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Link: https://lore.kernel.org/r/20210203150435.27941-8-wei.liu@kernel.org
We will need the partition ID for executing some hypercalls later.
Signed-off-by: Lillian Grassin-Drake <ligrassi@microsoft.com>
Co-Developed-by: Sunil Muthuswamy <sunilmut@microsoft.com>
Signed-off-by: Wei Liu <wei.liu@kernel.org>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Link: https://lore.kernel.org/r/20210203150435.27941-7-wei.liu@kernel.org
When Linux runs as the root partition, it will need to make hypercalls
which return data from the hypervisor.
Allocate pages for storing results when Linux runs as the root
partition.
Signed-off-by: Lillian Grassin-Drake <ligrassi@microsoft.com>
Co-Developed-by: Lillian Grassin-Drake <ligrassi@microsoft.com>
Signed-off-by: Wei Liu <wei.liu@kernel.org>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Link: https://lore.kernel.org/r/20210203150435.27941-6-wei.liu@kernel.org
If bit 22 of Group B Features is set, the guest has access to the
Isolation Configuration CPUID leaf. On x86, the first four bits
of EAX in this leaf provide the isolation type of the partition;
we entail three isolation types: 'SNP' (hardware-based isolation),
'VBS' (software-based isolation), and 'NONE' (no isolation).
Signed-off-by: Andrea Parri (Microsoft) <parri.andrea@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: x86@kernel.org
Cc: linux-arch@vger.kernel.org
Link: https://lore.kernel.org/r/20210201144814.2701-2-parri.andrea@gmail.com
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Signed-off-by: Wei Liu <wei.liu@kernel.org>
With commit 4df4cb9e99, the Hyper-V direct-mode STIMER is actually
initialized before LAPIC is initialized: see
apic_intr_mode_init()
x86_platform.apic_post_init()
hyperv_init()
hv_stimer_alloc()
apic_bsp_setup()
setup_local_APIC()
setup_local_APIC() temporarily disables LAPIC, initializes it and
re-eanble it. The direct-mode STIMER depends on LAPIC, and when it's
registered, it can be programmed immediately and the timer can fire
very soon:
hv_stimer_init
clockevents_config_and_register
clockevents_register_device
tick_check_new_device
tick_setup_device
tick_setup_periodic(), tick_setup_oneshot()
clockevents_program_event
When the timer fires in the hypervisor, if the LAPIC is in the
disabled state, new versions of Hyper-V ignore the event and don't inject
the timer interrupt into the VM, and hence the VM hangs when it boots.
Note: when the VM starts/reboots, the LAPIC is pre-enabled by the
firmware, so the window of LAPIC being temporarily disabled is pretty
small, and the issue can only happen once out of 100~200 reboots for
a 40-vCPU VM on one dev host, and on another host the issue doesn't
reproduce after 2000 reboots.
The issue is more noticeable for kdump/kexec, because the LAPIC is
disabled by the first kernel, and stays disabled until the kdump/kexec
kernel enables it. This is especially an issue to a Generation-2 VM
(for which Hyper-V doesn't emulate the PIT timer) when CONFIG_HZ=1000
(rather than CONFIG_HZ=250) is used.
Fix the issue by moving hv_stimer_alloc() to a later place where the
LAPIC timer is initialized.
Fixes: 4df4cb9e99 ("x86/hyperv: Initialize clockevents earlier in CPU onlining")
Signed-off-by: Dexuan Cui <decui@microsoft.com>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Link: https://lore.kernel.org/r/20210116223136.13892-1-decui@microsoft.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
We've observed crashes due to an empty cpu mask in
hyperv_flush_tlb_others. Obviously the cpu mask in question is changed
between the cpumask_empty call at the beginning of the function and when
it is actually used later.
One theory is that an interrupt comes in between and a code path ends up
changing the mask. Move the check after interrupt has been disabled to
see if it fixes the issue.
Signed-off-by: Wei Liu <wei.liu@kernel.org>
Cc: stable@kernel.org
Link: https://lore.kernel.org/r/20210105175043.28325-1-wei.liu@kernel.org
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Currently the kexec kernel can panic or hang due to 2 causes:
1) hv_cpu_die() is not called upon kexec, so the hypervisor corrupts the
old VP Assist Pages when the kexec kernel runs. The same issue is fixed
for hibernation in commit 421f090c81 ("x86/hyperv: Suspend/resume the
VP assist page for hibernation"). Now fix it for kexec.
2) hyperv_cleanup() is called too early. In the kexec path, the other CPUs
are stopped in hv_machine_shutdown() -> native_machine_shutdown(), so
between hv_kexec_handler() and native_machine_shutdown(), the other CPUs
can still try to access the hypercall page and cause panic. The workaround
"hv_hypercall_pg = NULL;" in hyperv_cleanup() is unreliabe. Move
hyperv_cleanup() to a better place.
Signed-off-by: Dexuan Cui <decui@microsoft.com>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Link: https://lore.kernel.org/r/20201222065541.24312-1-decui@microsoft.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
The comment about Hyper-V accessors is unclear regarding their
potential use in x2apic mode, as is the associated commit message
in e211288b72. Clarify that while the architectural and
synthetic MSRs are equivalent in x2apic mode, the full set of xapic
accessors cannot be used because of register layout differences.
Fixes: e211288b72 ("x86/hyperv: Make vapic support x2apic mode")
Signed-off-by: Michael Kelley <mikelley@microsoft.com>
Link: https://lore.kernel.org/r/1603723972-81303-1-git-send-email-mikelley@microsoft.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
In the architecture independent version of hyperv-tlfs.h, commit c55a844f46
removed the "X64" in the symbol names so they would make sense for both x86 and
ARM64. That commit added aliases with the "X64" in the x86 version of hyperv-tlfs.h
so that existing x86 code would continue to compile.
As a cleanup, update the x86 code to use the symbols without the "X64", then remove
the aliases. There's no functional change.
Signed-off-by: Joseph Salisbury <joseph.salisbury@microsoft.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Link: https://lore.kernel.org/r/1601130386-11111-1-git-send-email-jsalisbury@linux.microsoft.com
Fix the recently added new __vmalloc_node_range callers to pass the
correct values as the owner for display in /proc/vmallocinfo.
Fixes: 800e26b813 ("x86/hyperv: allocate the hypercall page with only read and execute bits")
Fixes: 10d5e97c1b ("arm64: use PAGE_KERNEL_ROX directly in alloc_insn_page")
Fixes: 7a0e27b2a0 ("mm: remove vmalloc_exec")
Reported-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/20200627075649.2455097-1-hch@lst.de
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Patch series "fix a hyperv W^X violation and remove vmalloc_exec"
Dexuan reported a W^X violation due to the fact that the hyper hypercall
page due switching it to be allocated using vmalloc_exec.
The problem is that PAGE_KERNEL_EXEC as used by vmalloc_exec actually
sets writable permissions in the pte. This series fixes the issue by
switching to the low-level __vmalloc_node_range interface that allows
specifing more detailed permissions instead. It then also open codes
the other two callers and removes the somewhat confusing vmalloc_exec
interface.
Peter noted that the hyper hypercall page allocation also has another
long standing issue in that it shouldn't use the full vmalloc but just
the module space. This issue is so far theoretical as the allocation is
done early in the boot process. I plan to fix it with another bigger
series for 5.9.
This patch (of 3):
Avoid a W^X violation cause by the fact that PAGE_KERNEL_EXEC includes
the writable bit.
For this resurrect the removed PAGE_KERNEL_RX definition, but as
PAGE_KERNEL_ROX to match arm64 and powerpc.
Link: http://lkml.kernel.org/r/20200618064307.32739-2-hch@lst.de
Fixes: 78bb17f76e ("x86/hyperv: use vmalloc_exec for the hypercall page")
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reported-by: Dexuan Cui <decui@microsoft.com>
Tested-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Acked-by: Wei Liu <wei.liu@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Jessica Yu <jeyu@kernel.org>
Cc: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Convert various hypervisor vectors to IDTENTRY_SYSVEC:
- Implement the C entry point with DEFINE_IDTENTRY_SYSVEC
- Emit the ASM stub with DECLARE_IDTENTRY_SYSVEC
- Remove the ASM idtentries in 64-bit
- Remove the BUILD_INTERRUPT entries in 32-bit
- Remove the old prototypes
No functional change.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Andy Lutomirski <luto@kernel.org>
Reviewed-by: Wei Liu <wei.liu@kernel.org>
Link: https://lore.kernel.org/r/20200521202119.647997594@linutronix.de
Patch series "decruft the vmalloc API", v2.
Peter noticed that with some dumb luck you can toast the kernel address
space with exported vmalloc symbols.
I used this as an opportunity to decruft the vmalloc.c API and make it
much more systematic. This also removes any chance to create vmalloc
mappings outside the designated areas or using executable permissions
from modules. Besides that it removes more than 300 lines of code.
This patch (of 29):
Use the designated helper for allocating executable kernel memory, and
remove the now unused PAGE_KERNEL_RX define.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Acked-by: Wei Liu <wei.liu@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Christophe Leroy <christophe.leroy@c-s.fr>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: David Airlie <airlied@linux.ie>
Cc: Gao Xiang <xiang@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Laura Abbott <labbott@redhat.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Nitin Gupta <ngupta@vflare.org>
Cc: Robin Murphy <robin.murphy@arm.com>
Cc: Sakari Ailus <sakari.ailus@linux.intel.com>
Cc: Stephen Hemminger <sthemmin@microsoft.com>
Cc: Sumit Semwal <sumit.semwal@linaro.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@ozlabs.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Link: http://lkml.kernel.org/r/20200414131348.444715-1-hch@lst.de
Link: http://lkml.kernel.org/r/20200414131348.444715-2-hch@lst.de
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Errors during hibernation with reenlightenment notifications enabled were
reported:
[ 51.730435] PM: hibernation entry
[ 51.737435] PM: Syncing filesystems ...
...
[ 54.102216] Disabling non-boot CPUs ...
[ 54.106633] smpboot: CPU 1 is now offline
[ 54.110006] unchecked MSR access error: WRMSR to 0x40000106 (tried to
write 0x47c72780000100ee) at rIP: 0xffffffff90062f24
native_write_msr+0x4/0x20)
[ 54.110006] Call Trace:
[ 54.110006] hv_cpu_die+0xd9/0xf0
...
Normally, hv_cpu_die() just reassigns reenlightenment notifications to some
other CPU when the CPU receiving them goes offline. Upon hibernation, there
is no other CPU which is still online so cpumask_any_but(cpu_online_mask)
returns >= nr_cpu_ids and using it as hv_vp_index index is incorrect.
Disable the feature when cpumask_any_but() fails.
Also, as we now disable reenlightenment notifications upon hibernation we
need to restore them on resume. Check if hv_reenlightenment_cb was
previously set and restore from hv_resume().
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: Dexuan Cui <decui@microsoft.com>
Reviewed-by: Tianyu Lan <Tianyu.Lan@microsoft.com>
Link: https://lore.kernel.org/r/20200512160153.134467-1-vkuznets@redhat.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
Unlike the other CPUs, CPU0 is never offlined during hibernation, so in the
resume path, the "new" kernel's VP assist page is not suspended (i.e. not
disabled), and later when we jump to the "old" kernel, the page is not
properly re-enabled for CPU0 with the allocated page from the old kernel.
So far, the VP assist page is used by hv_apic_eoi_write(), and is also
used in the case of nested virtualization (running KVM atop Hyper-V).
For hv_apic_eoi_write(), when the page is not properly re-enabled,
hvp->apic_assist is always 0, so the HV_X64_MSR_EOI MSR is always written.
This is not ideal with respect to performance, but Hyper-V can still
correctly handle this according to the Hyper-V spec; nevertheless, Linux
still must update the Hyper-V hypervisor with the correct VP assist page
to prevent Hyper-V from writing to the stale page, which causes guest
memory corruption and consequently may have caused the hangs and triple
faults seen during non-boot CPUs resume.
Fix the issue by calling hv_cpu_die()/hv_cpu_init() in the syscore ops.
Without the fix, hibernation can fail at a rate of 1/300 ~ 1/500.
With the fix, hibernation can pass a long-haul test of 2000 runs.
In the case of nested virtualization, disabling/reenabling the assist
page upon hibernation may be unsafe if there are active L2 guests.
It looks KVM should be enhanced to abort the hibernation request if
there is any active L2 guest.
Fixes: 05bd330a7f ("x86/hyperv: Suspend/resume the hypercall page for hibernation")
Cc: stable@vger.kernel.org
Signed-off-by: Dexuan Cui <decui@microsoft.com>
Link: https://lore.kernel.org/r/1587437171-2472-1-git-send-email-decui@microsoft.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
When oops happens with panic_on_oops unset, the oops
thread is killed by die() and system continues to run.
In such case, guest should not report crash register
data to host since system still runs. Check panic_on_oops
and return directly in hyperv_report_panic() when the function
is called in the die() and panic_on_oops is unset. Fix it.
Fixes: 7ed4325a44 ("Drivers: hv: vmbus: Make panic reporting to be more useful")
Signed-off-by: Tianyu Lan <Tianyu.Lan@microsoft.com>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Link: https://lore.kernel.org/r/20200406155331.2105-7-Tianyu.Lan@microsoft.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
Vitaly Kuznetsov
Jiapeng Chong
Wan Jiabing
Tianyu Lan
Linus Torvalds
Wei Liu
Praveen Kumar
Michael Kelley
Joseph Salisbury
Zheng Yongjun
Sunil Muthuswamy
Xu Yihang
Ingo Molnar
Nadav Amit
Andrea Parri (Microsoft)
Dexuan Cui
Christoph Hellwig
Thomas Gleixner