diff options
| -rw-r--r-- | arch/x86/kvm/pmu.c | 3 | ||||
| -rw-r--r-- | arch/x86/kvm/x86.c | 10 |
2 files changed, 12 insertions, 1 deletions
diff --git a/arch/x86/kvm/pmu.c b/arch/x86/kvm/pmu.c index 29492c2a0c82..136184fe9e92 100644 --- a/arch/x86/kvm/pmu.c +++ b/arch/x86/kvm/pmu.c @@ -589,6 +589,9 @@ int kvm_pmu_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info) */ void kvm_pmu_refresh(struct kvm_vcpu *vcpu) { + if (KVM_BUG_ON(kvm_vcpu_has_run(vcpu), vcpu->kvm)) + return; + bitmap_zero(vcpu_to_pmu(vcpu)->all_valid_pmc_idx, X86_PMC_IDX_MAX); static_call(kvm_x86_pmu_refresh)(vcpu); } diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index cf33b7d910a6..a86ad45a53b8 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -3632,9 +3632,17 @@ int kvm_set_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info) if (data & ~kvm_caps.supported_perf_cap) return 1; + /* + * Note, this is not just a performance optimization! KVM + * disallows changing feature MSRs after the vCPU has run; PMU + * refresh will bug the VM if called after the vCPU has run. + */ + if (vcpu->arch.perf_capabilities == data) + break; + vcpu->arch.perf_capabilities = data; kvm_pmu_refresh(vcpu); - return 0; + break; case MSR_EFER: return set_efer(vcpu, msr_info); case MSR_K7_HWCR: |