6.6-stable review patch. If anyone has any objections, please let me know.
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From: Sean Christopherson seanjc@google.com
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@vger.kernel.org Reviewed-by: Dapeng Mi dapeng1.mi@linux.intel.com Link: https://lore.kernel.org/r/20231103230541.352265-3-seanjc@google.com Signed-off-by: Sean Christopherson seanjc@google.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- 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);