From: Sandipan Das Date: Wed, 27 Apr 2022 11:31:49 +0000 (+0530) Subject: kvm: x86/cpuid: Only provide CPUID leaf 0xA if host has architectural PMU X-Git-Tag: v5.15.73~4429 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=11f5f236dbd6e685356e10f158e306e592cb70ff;p=platform%2Fkernel%2Flinux-rpi.git kvm: x86/cpuid: Only provide CPUID leaf 0xA if host has architectural PMU [ Upstream commit 5a1bde46f98b893cda6122b00e94c0c40a6ead3c ] 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 Signed-off-by: Sandipan Das Message-Id: <3fef83d9c2b2f7516e8ff50d60851f29a4bcb716.1651058600.git.sandipan.das@amd.com> Signed-off-by: Paolo Bonzini Signed-off-by: Sasha Levin --- diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c index 5f1d4a5..b17c9b00 100644 --- a/arch/x86/kvm/cpuid.c +++ b/arch/x86/kvm/cpuid.c @@ -725,6 +725,11 @@ 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); /*