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| author | Paolo Bonzini <pbonzini@redhat.com> | 2021-02-02 17:36:08 +0300 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2021-02-04 13:27:24 +0300 |
| commit | 9c9520ce883386dc3794c7d60204487ff1db09cb (patch) | |
| tree | 6a973ed310fb4a63ddf2eb8ad4e8664d536cee33 /arch/x86/kvm/vmx/pmu_intel.c | |
| parent | a755753903a40d982f6dd23d65eb96b248a2577a (diff) | |
| download | linux-9c9520ce883386dc3794c7d60204487ff1db09cb.tar.xz | |
KVM: vmx/pmu: Add PMU_CAP_LBR_FMT check when guest LBR is enabled
Usespace could set the bits [0, 5] of the IA32_PERF_CAPABILITIES
MSR which tells about the record format stored in the LBR records.
The LBR will be enabled on the guest if host perf supports LBR
(checked via x86_perf_get_lbr()) and the vcpu model is compatible
with the host one.
Signed-off-by: Like Xu <like.xu@linux.intel.com>
Message-Id: <20210201051039.255478-4-like.xu@linux.intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86/kvm/vmx/pmu_intel.c')
| -rw-r--r-- | arch/x86/kvm/vmx/pmu_intel.c | 19 |
1 files changed, 19 insertions, 0 deletions
diff --git a/arch/x86/kvm/vmx/pmu_intel.c b/arch/x86/kvm/vmx/pmu_intel.c index 7403d46998d6..d21104e6f9ec 100644 --- a/arch/x86/kvm/vmx/pmu_intel.c +++ b/arch/x86/kvm/vmx/pmu_intel.c @@ -173,6 +173,16 @@ static inline struct kvm_pmc *get_fw_gp_pmc(struct kvm_pmu *pmu, u32 msr) return get_gp_pmc(pmu, msr, MSR_IA32_PMC0); } +bool intel_pmu_lbr_is_compatible(struct kvm_vcpu *vcpu) +{ + /* + * As a first step, a guest could only enable LBR feature if its + * cpu model is the same as the host because the LBR registers + * would be pass-through to the guest and they're model specific. + */ + return boot_cpu_data.x86_model == guest_cpuid_model(vcpu); +} + static bool intel_is_valid_msr(struct kvm_vcpu *vcpu, u32 msr) { struct kvm_pmu *pmu = vcpu_to_pmu(vcpu); @@ -321,6 +331,8 @@ static int intel_pmu_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info) static void intel_pmu_refresh(struct kvm_vcpu *vcpu) { struct kvm_pmu *pmu = vcpu_to_pmu(vcpu); + struct lbr_desc *lbr_desc = vcpu_to_lbr_desc(vcpu); + struct x86_pmu_capability x86_pmu; struct kvm_cpuid_entry2 *entry; union cpuid10_eax eax; @@ -387,12 +399,18 @@ static void intel_pmu_refresh(struct kvm_vcpu *vcpu) INTEL_PMC_MAX_GENERIC, pmu->nr_arch_fixed_counters); nested_vmx_pmu_entry_exit_ctls_update(vcpu); + + if (intel_pmu_lbr_is_compatible(vcpu)) + x86_perf_get_lbr(&lbr_desc->records); + else + lbr_desc->records.nr = 0; } static void intel_pmu_init(struct kvm_vcpu *vcpu) { int i; struct kvm_pmu *pmu = vcpu_to_pmu(vcpu); + struct lbr_desc *lbr_desc = vcpu_to_lbr_desc(vcpu); for (i = 0; i < INTEL_PMC_MAX_GENERIC; i++) { pmu->gp_counters[i].type = KVM_PMC_GP; @@ -409,6 +427,7 @@ static void intel_pmu_init(struct kvm_vcpu *vcpu) } vcpu->arch.perf_capabilities = vmx_get_perf_capabilities(); + lbr_desc->records.nr = 0; } static void intel_pmu_reset(struct kvm_vcpu *vcpu) |