* [tip: perf/core] kvm: x86/cpuid: Fix CPUID leaf 0xA
@ 2022-04-29 20:28 tip-bot2 for Sandipan Das
2022-05-09 17:24 ` Borislav Petkov
0 siblings, 1 reply; 5+ messages in thread
From: tip-bot2 for Sandipan Das @ 2022-04-29 20:28 UTC (permalink / raw)
To: linux-tip-commits
Cc: Vasant Hegde, Sandipan Das, Peter Zijlstra (Intel), x86, linux-kernel
The following commit has been merged into the perf/core branch of tip:
Commit-ID: fafd15ab6dc1fdfff66908e6d9231b124e1875cf
Gitweb: https://git.kernel.org/tip/fafd15ab6dc1fdfff66908e6d9231b124e1875cf
Author: Sandipan Das <sandipan.das@amd.com>
AuthorDate: Thu, 21 Apr 2022 11:16:59 +05:30
Committer: Peter Zijlstra <peterz@infradead.org>
CommitterDate: Fri, 29 Apr 2022 11:06:27 +02:00
kvm: x86/cpuid: Fix CPUID leaf 0xA
On some x86 processors, CPUID leaf 0xA provides information
on Architectural Performance Monitoring features. It
advertises a PMU version which Qemu uses to determine the
availability of additional MSRs to manage the PMCs.
Upon receiving a KVM_GET_SUPPORTED_CPUID ioctl request for
the same, the kernel constructs return values based on the
x86_pmu_capability irrespective of the vendor.
This leaf and the additional MSRs are not supported on AMD
processors. If PerfMonV2 is detected, the PMU version is
set to 2 and guest startup breaks because of an attempt to
access a non-existent MSR. Return zeros to avoid this.
Fixes: a6c06ed1a60a ("KVM: Expose the architectural performance monitoring CPUID leaf")
Reported-by: Vasant Hegde <vasant.hegde@amd.com>
Signed-off-by: Sandipan Das <sandipan.das@amd.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/54bc7fe4cadf6bdef823bab1fba43d4891d2e1a9.1650515382.git.sandipan.das@amd.com
---
arch/x86/kvm/cpuid.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index b24ca7f..ae1d963 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -887,6 +887,12 @@ static inline int __do_cpuid_func(struct kvm_cpuid_array *array, u32 function)
union cpuid10_eax eax;
union cpuid10_edx edx;
+ if (boot_cpu_data.x86_vendor == X86_VENDOR_AMD ||
+ boot_cpu_data.x86_vendor == X86_VENDOR_HYGON) {
+ entry->eax = entry->ebx = entry->ecx = entry->edx = 0;
+ break;
+ }
+
perf_get_x86_pmu_capability(&cap);
/*
^ permalink raw reply related [flat|nested] 5+ messages in thread* Re: [tip: perf/core] kvm: x86/cpuid: Fix CPUID leaf 0xA
2022-04-29 20:28 [tip: perf/core] kvm: x86/cpuid: Fix CPUID leaf 0xA tip-bot2 for Sandipan Das
@ 2022-05-09 17:24 ` Borislav Petkov
2022-05-10 4:59 ` Sandipan Das
0 siblings, 1 reply; 5+ messages in thread
From: Borislav Petkov @ 2022-05-09 17:24 UTC (permalink / raw)
To: Sandipan Das
Cc: linux-tip-commits, Vasant Hegde, Sandipan Das,
Peter Zijlstra (Intel),
x86, linux-kernel
On Fri, Apr 29, 2022 at 08:28:48PM -0000, tip-bot2 for Sandipan Das wrote:
> The following commit has been merged into the perf/core branch of tip:
>
> Commit-ID: fafd15ab6dc1fdfff66908e6d9231b124e1875cf
> Gitweb: https://git.kernel.org/tip/fafd15ab6dc1fdfff66908e6d9231b124e1875cf
> Author: Sandipan Das <sandipan.das@amd.com>
> AuthorDate: Thu, 21 Apr 2022 11:16:59 +05:30
> Committer: Peter Zijlstra <peterz@infradead.org>
> CommitterDate: Fri, 29 Apr 2022 11:06:27 +02:00
>
> kvm: x86/cpuid: Fix CPUID leaf 0xA
>
> On some x86 processors, CPUID leaf 0xA provides information
> on Architectural Performance Monitoring features. It
> advertises a PMU version which Qemu uses to determine the
> availability of additional MSRs to manage the PMCs.
>
> Upon receiving a KVM_GET_SUPPORTED_CPUID ioctl request for
> the same, the kernel constructs return values based on the
> x86_pmu_capability irrespective of the vendor.
>
> This leaf and the additional MSRs are not supported on AMD
> processors. If PerfMonV2 is detected, the PMU version is
> set to 2 and guest startup breaks because of an attempt to
> access a non-existent MSR. Return zeros to avoid this.
>
> Fixes: a6c06ed1a60a ("KVM: Expose the architectural performance monitoring CPUID leaf")
> Reported-by: Vasant Hegde <vasant.hegde@amd.com>
> Signed-off-by: Sandipan Das <sandipan.das@amd.com>
> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
> Link: https://lkml.kernel.org/r/54bc7fe4cadf6bdef823bab1fba43d4891d2e1a9.1650515382.git.sandipan.das@amd.com
> ---
> arch/x86/kvm/cpuid.c | 6 ++++++
> 1 file changed, 6 insertions(+)
>
> diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
> index b24ca7f..ae1d963 100644
> --- a/arch/x86/kvm/cpuid.c
> +++ b/arch/x86/kvm/cpuid.c
> @@ -887,6 +887,12 @@ static inline int __do_cpuid_func(struct kvm_cpuid_array *array, u32 function)
> union cpuid10_eax eax;
> union cpuid10_edx edx;
>
> + if (boot_cpu_data.x86_vendor == X86_VENDOR_AMD ||
> + boot_cpu_data.x86_vendor == X86_VENDOR_HYGON) {
> + entry->eax = entry->ebx = entry->ecx = entry->edx = 0;
> + break;
> + }
> +
This is all fine and dandy but this patch in tip conflicts with the very
similar patch of yours:
5a1bde46f98b ("kvm: x86/cpuid: Only provide CPUID leaf 0xA if host has architectural PMU")
which is already upstream.
So which is it? Should we zap this version in tip instead?
--
Regards/Gruss,
Boris.
https://people.kernel.org/tglx/notes-about-netiquette
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [tip: perf/core] kvm: x86/cpuid: Fix CPUID leaf 0xA
2022-05-09 17:24 ` Borislav Petkov
@ 2022-05-10 4:59 ` Sandipan Das
2022-05-10 9:35 ` Peter Zijlstra
0 siblings, 1 reply; 5+ messages in thread
From: Sandipan Das @ 2022-05-10 4:59 UTC (permalink / raw)
To: Borislav Petkov
Cc: linux-tip-commits, Vasant Hegde, Peter Zijlstra (Intel),
pbonzini, x86, linux-kernel
Hi Boris,
On 5/9/2022 10:54 PM, Borislav Petkov wrote:
> On Fri, Apr 29, 2022 at 08:28:48PM -0000, tip-bot2 for Sandipan Das wrote:
>> The following commit has been merged into the perf/core branch of tip:
>>
>> Commit-ID: fafd15ab6dc1fdfff66908e6d9231b124e1875cf
>> Gitweb: https://git.kernel.org/tip/fafd15ab6dc1fdfff66908e6d9231b124e1875cf
>> Author: Sandipan Das <sandipan.das@amd.com>
>> AuthorDate: Thu, 21 Apr 2022 11:16:59 +05:30
>> Committer: Peter Zijlstra <peterz@infradead.org>
>> CommitterDate: Fri, 29 Apr 2022 11:06:27 +02:00
>>
>> kvm: x86/cpuid: Fix CPUID leaf 0xA
>>
>> On some x86 processors, CPUID leaf 0xA provides information
>> on Architectural Performance Monitoring features. It
>> advertises a PMU version which Qemu uses to determine the
>> availability of additional MSRs to manage the PMCs.
>>
>> Upon receiving a KVM_GET_SUPPORTED_CPUID ioctl request for
>> the same, the kernel constructs return values based on the
>> x86_pmu_capability irrespective of the vendor.
>>
>> This leaf and the additional MSRs are not supported on AMD
>> processors. If PerfMonV2 is detected, the PMU version is
>> set to 2 and guest startup breaks because of an attempt to
>> access a non-existent MSR. Return zeros to avoid this.
>>
>> Fixes: a6c06ed1a60a ("KVM: Expose the architectural performance monitoring CPUID leaf")
>> Reported-by: Vasant Hegde <vasant.hegde@amd.com>
>> Signed-off-by: Sandipan Das <sandipan.das@amd.com>
>> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
>> Link: https://lkml.kernel.org/r/54bc7fe4cadf6bdef823bab1fba43d4891d2e1a9.1650515382.git.sandipan.das@amd.com
>> ---
>> arch/x86/kvm/cpuid.c | 6 ++++++
>> 1 file changed, 6 insertions(+)
>>
>> diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
>> index b24ca7f..ae1d963 100644
>> --- a/arch/x86/kvm/cpuid.c
>> +++ b/arch/x86/kvm/cpuid.c
>> @@ -887,6 +887,12 @@ static inline int __do_cpuid_func(struct kvm_cpuid_array *array, u32 function)
>> union cpuid10_eax eax;
>> union cpuid10_edx edx;
>>
>> + if (boot_cpu_data.x86_vendor == X86_VENDOR_AMD ||
>> + boot_cpu_data.x86_vendor == X86_VENDOR_HYGON) {
>> + entry->eax = entry->ebx = entry->ecx = entry->edx = 0;
>> + break;
>> + }
>> +
>
> This is all fine and dandy but this patch in tip conflicts with the very
> similar patch of yours:
>
> 5a1bde46f98b ("kvm: x86/cpuid: Only provide CPUID leaf 0xA if host has architectural PMU")
>
> which is already upstream.
>
> So which is it? Should we zap this version in tip instead?
>
Please remove this patch and keep commit 5a1bde46f98b instead.
- Sandipan
^ permalink raw reply [flat|nested] 5+ messages in thread
* [tip: perf/core] kvm: x86/cpuid: Fix CPUID leaf 0xA
@ 2022-05-04 9:23 tip-bot2 for Sandipan Das
0 siblings, 0 replies; 5+ messages in thread
From: tip-bot2 for Sandipan Das @ 2022-05-04 9:23 UTC (permalink / raw)
To: linux-tip-commits
Cc: Vasant Hegde, Sandipan Das, Peter Zijlstra (Intel), x86, linux-kernel
The following commit has been merged into the perf/core branch of tip:
Commit-ID: 202c3484768bce3f077efbbcc1eaa9cac8010093
Gitweb: https://git.kernel.org/tip/202c3484768bce3f077efbbcc1eaa9cac8010093
Author: Sandipan Das <sandipan.das@amd.com>
AuthorDate: Thu, 21 Apr 2022 11:16:59 +05:30
Committer: Peter Zijlstra <peterz@infradead.org>
CommitterDate: Wed, 04 May 2022 11:18:27 +02:00
kvm: x86/cpuid: Fix CPUID leaf 0xA
On some x86 processors, CPUID leaf 0xA provides information
on Architectural Performance Monitoring features. It
advertises a PMU version which Qemu uses to determine the
availability of additional MSRs to manage the PMCs.
Upon receiving a KVM_GET_SUPPORTED_CPUID ioctl request for
the same, the kernel constructs return values based on the
x86_pmu_capability irrespective of the vendor.
This leaf and the additional MSRs are not supported on AMD
processors. If PerfMonV2 is detected, the PMU version is
set to 2 and guest startup breaks because of an attempt to
access a non-existent MSR. Return zeros to avoid this.
Fixes: a6c06ed1a60a ("KVM: Expose the architectural performance monitoring CPUID leaf")
Reported-by: Vasant Hegde <vasant.hegde@amd.com>
Signed-off-by: Sandipan Das <sandipan.das@amd.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/54bc7fe4cadf6bdef823bab1fba43d4891d2e1a9.1650515382.git.sandipan.das@amd.com
---
arch/x86/kvm/cpuid.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index b24ca7f..ae1d963 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -887,6 +887,12 @@ static inline int __do_cpuid_func(struct kvm_cpuid_array *array, u32 function)
union cpuid10_eax eax;
union cpuid10_edx edx;
+ if (boot_cpu_data.x86_vendor == X86_VENDOR_AMD ||
+ boot_cpu_data.x86_vendor == X86_VENDOR_HYGON) {
+ entry->eax = entry->ebx = entry->ecx = entry->edx = 0;
+ break;
+ }
+
perf_get_x86_pmu_capability(&cap);
/*
^ permalink raw reply related [flat|nested] 5+ messages in thread
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2022-04-29 20:28 [tip: perf/core] kvm: x86/cpuid: Fix CPUID leaf 0xA tip-bot2 for Sandipan Das
2022-05-09 17:24 ` Borislav Petkov
2022-05-10 4:59 ` Sandipan Das
2022-05-10 9:35 ` Peter Zijlstra
2022-05-04 9:23 tip-bot2 for Sandipan Das
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