diff options
| author | Sean Christopherson <seanjc@google.com> | 2022-07-22 22:44:07 +0000 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2022-07-28 13:23:57 -0400 |
| commit | b663f0b5f3d665c261256d1f76e98f077c6e56af (patch) | |
| tree | 8777e738715206876273b1ed9c29848d5c4e4838 /arch/x86 | |
| parent | 93255bf92939d948bc86d81c6bb70bb0fecc5db1 (diff) | |
| download | linux-b663f0b5f3d665c261256d1f76e98f077c6e56af.tar.bz2 | |
KVM: VMX: Add helper to check if the guest PMU has PERF_GLOBAL_CTRL
Add a helper to check of the guest PMU has PERF_GLOBAL_CTRL, which is
unintuitive _and_ diverges from Intel's architecturally defined behavior.
Even worse, KVM currently implements the check using two different (but
equivalent) checks, _and_ there has been at least one attempt to add a
_third_ flavor.
Cc: stable@vger.kernel.org
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20220722224409.1336532-4-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86')
| -rw-r--r-- | arch/x86/kvm/vmx/pmu_intel.c | 4 | ||||
| -rw-r--r-- | arch/x86/kvm/vmx/vmx.h | 12 |
2 files changed, 14 insertions, 2 deletions
diff --git a/arch/x86/kvm/vmx/pmu_intel.c b/arch/x86/kvm/vmx/pmu_intel.c index 6e355c5d2f40..78f2800fd850 100644 --- a/arch/x86/kvm/vmx/pmu_intel.c +++ b/arch/x86/kvm/vmx/pmu_intel.c @@ -111,7 +111,7 @@ static bool intel_pmc_is_enabled(struct kvm_pmc *pmc) { struct kvm_pmu *pmu = pmc_to_pmu(pmc); - if (pmu->version < 2) + if (!intel_pmu_has_perf_global_ctrl(pmu)) return true; return test_bit(pmc->idx, (unsigned long *)&pmu->global_ctrl); @@ -207,7 +207,7 @@ static bool intel_is_valid_msr(struct kvm_vcpu *vcpu, u32 msr) case MSR_CORE_PERF_GLOBAL_STATUS: case MSR_CORE_PERF_GLOBAL_CTRL: case MSR_CORE_PERF_GLOBAL_OVF_CTRL: - ret = pmu->version > 1; + return intel_pmu_has_perf_global_ctrl(pmu); break; case MSR_IA32_PEBS_ENABLE: ret = vcpu_get_perf_capabilities(vcpu) & PERF_CAP_PEBS_FORMAT; diff --git a/arch/x86/kvm/vmx/vmx.h b/arch/x86/kvm/vmx/vmx.h index 286c88e285ea..2a0b94e0fda7 100644 --- a/arch/x86/kvm/vmx/vmx.h +++ b/arch/x86/kvm/vmx/vmx.h @@ -91,6 +91,18 @@ union vmx_exit_reason { u32 full; }; +static inline bool intel_pmu_has_perf_global_ctrl(struct kvm_pmu *pmu) +{ + /* + * Architecturally, Intel's SDM states that IA32_PERF_GLOBAL_CTRL is + * supported if "CPUID.0AH: EAX[7:0] > 0", i.e. if the PMU version is + * greater than zero. However, KVM only exposes and emulates the MSR + * to/for the guest if the guest PMU supports at least "Architectural + * Performance Monitoring Version 2". + */ + return pmu->version > 1; +} + #define vcpu_to_lbr_desc(vcpu) (&to_vmx(vcpu)->lbr_desc) #define vcpu_to_lbr_records(vcpu) (&to_vmx(vcpu)->lbr_desc.records) |