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@xxxxxxx> AuthorDate: Thu, 21 Apr 2022 11:16:59 +05:30 Committer: Peter Zijlstra <peterz@xxxxxxxxxxxxx> 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@xxxxxxx> Signed-off-by: Sandipan Das <sandipan.das@xxxxxxx> Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx> Link: https://lkml.kernel.org/r/54bc7fe4cadf6bdef823bab1fba43d4891d2e1a9.1650515382.git.sandipan.das@xxxxxxx --- 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); /*
![]() |