6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Sean Christopherson <seanjc@xxxxxxxxxx> commit 1647b52757d59131fe30cf73fa36fac834d4367f upstream. 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@xxxxxxxxxxxxxxx Reviewed-by: Dapeng Mi <dapeng1.mi@xxxxxxxxxxxxxxx> Link: https://lore.kernel.org/r/20231103230541.352265-3-seanjc@xxxxxxxxxx Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- arch/x86/kvm/pmu.c | 35 ++++++++++++++++++++++------------- 1 file changed, 22 insertions(+), 13 deletions(-) --- a/arch/x86/kvm/pmu.c +++ b/arch/x86/kvm/pmu.c @@ -657,25 +657,14 @@ int kvm_pmu_set_msr(struct kvm_vcpu *vcp 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);
