Messages in this thread Patch in this message | | | Date | Fri, 3 Nov 2023 16:05:37 -0700 | Subject | [PATCH v2 2/6] KVM: x86/pmu: Reset the PMU, i.e. stop counters, before refreshing | From | Sean Christopherson <> |
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Stop all counters and release all perf events before refreshing the vPMU, i.e. before reconfiguring the vPMU to respond to changes in the vCPU model.
Clear need_cleanup in kvm_pmu_reset() as well so that KVM doesn't prematurely stop counters, e.g. if KVM enters the guest and enables counters before the vCPU is scheduled out.
Cc: stable@vger.kernel.org Reviewed-by: Dapeng Mi <dapeng1.mi@linux.intel.com> Signed-off-by: Sean Christopherson <seanjc@google.com> --- arch/x86/kvm/pmu.c | 35 ++++++++++++++++++++++------------- 1 file changed, 22 insertions(+), 13 deletions(-)
diff --git a/arch/x86/kvm/pmu.c b/arch/x86/kvm/pmu.c index 027e9c3c2b93..dc8e8e907cfb 100644 --- a/arch/x86/kvm/pmu.c +++ b/arch/x86/kvm/pmu.c @@ -657,25 +657,14 @@ int kvm_pmu_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info) return 0; } -/* refresh PMU settings. This function generally is called when underlying - * settings are changed (such as changes of PMU CPUID by guest VMs), which - * should rarely happen. - */ -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); -} - void kvm_pmu_reset(struct kvm_vcpu *vcpu) { struct kvm_pmu *pmu = vcpu_to_pmu(vcpu); struct kvm_pmc *pmc; int i; + pmu->need_cleanup = false; + bitmap_zero(pmu->reprogram_pmi, X86_PMC_IDX_MAX); for_each_set_bit(i, pmu->all_valid_pmc_idx, X86_PMC_IDX_MAX) { @@ -695,6 +684,26 @@ void kvm_pmu_reset(struct kvm_vcpu *vcpu) static_call_cond(kvm_x86_pmu_reset)(vcpu); } + +/* + * Refresh the PMU configuration for the vCPU, e.g. if userspace changes CPUID + * and/or PERF_CAPABILITIES. + */ +void kvm_pmu_refresh(struct kvm_vcpu *vcpu) +{ + if (KVM_BUG_ON(kvm_vcpu_has_run(vcpu), vcpu->kvm)) + return; + + /* + * Stop/release all existing counters/events before realizing the new + * vPMU model. + */ + kvm_pmu_reset(vcpu); + + bitmap_zero(vcpu_to_pmu(vcpu)->all_valid_pmc_idx, X86_PMC_IDX_MAX); + static_call(kvm_x86_pmu_refresh)(vcpu); +} + void kvm_pmu_init(struct kvm_vcpu *vcpu) { struct kvm_pmu *pmu = vcpu_to_pmu(vcpu); -- 2.42.0.869.gea05f2083d-goog
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