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KVM: x86/pmu: Reset the PMU, i.e. stop counters, before refreshing

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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>
Link: https://lore.kernel.org/r/20231103230541.352265-3-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
This commit is contained in:
Sean Christopherson 2023-11-03 16:05:37 -07:00
parent cbb359d81a
commit 1647b52757
1 changed files with 22 additions and 13 deletions
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35
arch/x86/kvm/pmu.c
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@ -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);