From b663f0b5f3d665c261256d1f76e98f077c6e56af Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Fri, 22 Jul 2022 22:44:07 +0000 Subject: 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 Message-Id: <20220722224409.1336532-4-seanjc@google.com> Signed-off-by: Paolo Bonzini --- arch/x86/kvm/vmx/vmx.h | 12 ++++++++++++ 1 file changed, 12 insertions(+) (limited to 'arch/x86/kvm/vmx/vmx.h') 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) -- cgit