From: Like Xu Date: Sat, 3 Jun 2023 01:10:54 +0000 (-0700) Subject: KVM: x86/pmu: Advertise PERFCTR_CORE iff the min nr of counters is met X-Git-Tag: v6.5-rc1~71^2~3^2~4 X-Git-Url: http://git.osdn.net/view?a=commitdiff_plain;h=d338d8789e64b2d8ed2f82f9364c415d6efa118d;p=tomoyo%2Ftomoyo-test1.git KVM: x86/pmu: Advertise PERFCTR_CORE iff the min nr of counters is met Enable and advertise PERFCTR_CORE if and only if the minimum number of required counters are available, i.e. if perf says there are less than six general purpose counters. Opportunistically, use kvm_cpu_cap_check_and_set() instead of open coding the check for host support. Suggested-by: Sean Christopherson Signed-off-by: Like Xu [sean: massage shortlog and changelog] Link: https://lore.kernel.org/r/20230603011058.1038821-9-seanjc@google.com Signed-off-by: Sean Christopherson --- diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c index ca32389f3c36..d9669e3cc00a 100644 --- a/arch/x86/kvm/svm/svm.c +++ b/arch/x86/kvm/svm/svm.c @@ -5025,9 +5025,18 @@ static __init void svm_set_cpu_caps(void) boot_cpu_has(X86_FEATURE_AMD_SSBD)) kvm_cpu_cap_set(X86_FEATURE_VIRT_SSBD); - /* AMD PMU PERFCTR_CORE CPUID */ - if (enable_pmu && boot_cpu_has(X86_FEATURE_PERFCTR_CORE)) - kvm_cpu_cap_set(X86_FEATURE_PERFCTR_CORE); + if (enable_pmu) { + /* + * Enumerate support for PERFCTR_CORE if and only if KVM has + * access to enough counters to virtualize "core" support, + * otherwise limit vPMU support to the legacy number of counters. + */ + if (kvm_pmu_cap.num_counters_gp < AMD64_NUM_COUNTERS_CORE) + kvm_pmu_cap.num_counters_gp = min(AMD64_NUM_COUNTERS, + kvm_pmu_cap.num_counters_gp); + else + kvm_cpu_cap_check_and_set(X86_FEATURE_PERFCTR_CORE); + } /* CPUID 0x8000001F (SME/SEV features) */ sev_set_cpu_caps();