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

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>
This commit is contained in:
Sean Christopherson 2023-11-03 16:05:37 -07:00 committed by Greg Kroah-Hartman
parent 57bbd59ae0
commit 7c7ddf4586
1 changed files with 22 additions and 13 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

35
arch/x86/kvm/pmu.c
View File

@ -657,25 +657,14 @@ int kvm_pmu_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
return 0; 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) void kvm_pmu_reset(struct kvm_vcpu *vcpu)
{ {
struct kvm_pmu *pmu = vcpu_to_pmu(vcpu); struct kvm_pmu *pmu = vcpu_to_pmu(vcpu);
struct kvm_pmc *pmc; struct kvm_pmc *pmc;
int i; int i;
pmu->need_cleanup = false;
bitmap_zero(pmu->reprogram_pmi, X86_PMC_IDX_MAX); bitmap_zero(pmu->reprogram_pmi, X86_PMC_IDX_MAX);
for_each_set_bit(i, pmu->all_valid_pmc_idx, 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); 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) void kvm_pmu_init(struct kvm_vcpu *vcpu)
{ {
struct kvm_pmu *pmu = vcpu_to_pmu(vcpu); struct kvm_pmu *pmu = vcpu_to_pmu(vcpu);