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| author | Sandipan Das <sandipan.das@amd.com> | 2022-04-27 17:01:49 +0530 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2022-05-03 08:05:08 -0400 |
| commit | 5a1bde46f98b893cda6122b00e94c0c40a6ead3c (patch) | |
| tree | 39a40f4c2e24ecc37f7d72a67f6f75692eaf32b0 /arch/x86/kvm | |
| parent | 5eb849322d7f7ae9d5c587c7bc3b4f7c6872cd2f (diff) | |
| download | linux-5a1bde46f98b893cda6122b00e94c0c40a6ead3c.tar.bz2 | |
kvm: x86/cpuid: Only provide CPUID leaf 0xA if host has architectural PMU
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
and Hygon processors. If AMD 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>
Message-Id: <3fef83d9c2b2f7516e8ff50d60851f29a4bcb716.1651058600.git.sandipan.das@amd.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86/kvm')
| -rw-r--r-- | arch/x86/kvm/cpuid.c | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c index b24ca7f4ed7c..732724ea5b10 100644 --- a/arch/x86/kvm/cpuid.c +++ b/arch/x86/kvm/cpuid.c @@ -887,6 +887,11 @@ static inline int __do_cpuid_func(struct kvm_cpuid_array *array, u32 function) union cpuid10_eax eax; union cpuid10_edx edx; + if (!static_cpu_has(X86_FEATURE_ARCH_PERFMON)) { + entry->eax = entry->ebx = entry->ecx = entry->edx = 0; + break; + } + perf_get_x86_pmu_capability(&cap); /* |