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KVM: x86/pmu: Handle emulated instruction for mediated vPMU

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Mediated vPMU needs to accumulate the emulated instructions into counter
and load the counter into HW at vm-entry.

Moreover, if the accumulation leads to counter overflow, KVM needs to
update GLOBAL_STATUS and inject PMI into guest as well.

Suggested-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Dapeng Mi <dapeng1.mi@linux.intel.com>
Signed-off-by: Mingwei Zhang <mizhang@google.com>
Tested-by: Xudong Hao <xudong.hao@intel.com>
Tested-by: Manali Shukla <manali.shukla@amd.com>
Link: https://patch.msgid.link/20251206001720.468579-30-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
This commit is contained in:
Dapeng Mi 2025-12-05 16:17:05 -08:00 committed by Sean Christopherson
parent f7a65e58d6
commit 283a5aa57b
1 changed files with 37 additions and 2 deletions
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39
arch/x86/kvm/pmu.c
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@ -1031,10 +1031,45 @@ void kvm_pmu_destroy(struct kvm_vcpu *vcpu)
kvm_pmu_reset(vcpu);
}
static bool pmc_is_pmi_enabled(struct kvm_pmc *pmc)
{
u8 fixed_ctr_ctrl;
if (pmc_is_gp(pmc))
return pmc->eventsel & ARCH_PERFMON_EVENTSEL_INT;
fixed_ctr_ctrl = fixed_ctrl_field(pmc_to_pmu(pmc)->fixed_ctr_ctrl,
pmc->idx - KVM_FIXED_PMC_BASE_IDX);
return fixed_ctr_ctrl & INTEL_FIXED_0_ENABLE_PMI;
}
static void kvm_pmu_incr_counter(struct kvm_pmc *pmc)
{
pmc->emulated_counter++;
kvm_pmu_request_counter_reprogram(pmc);
struct kvm_vcpu *vcpu = pmc->vcpu;
/*
* For perf-based PMUs, accumulate software-emulated events separately
* from pmc->counter, as pmc->counter is offset by the count of the
* associated perf event. Request reprogramming, which will consult
* both emulated and hardware-generated events to detect overflow.
*/
if (!kvm_vcpu_has_mediated_pmu(vcpu)) {
pmc->emulated_counter++;
kvm_pmu_request_counter_reprogram(pmc);
return;
}
/*
* For mediated PMUs, pmc->counter is updated when the vCPU's PMU is
* put, and will be loaded into hardware when the PMU is loaded. Simply
* increment the counter and signal overflow if it wraps to zero.
*/
pmc->counter = (pmc->counter + 1) & pmc_bitmask(pmc);
if (!pmc->counter) {
pmc_to_pmu(pmc)->global_status |= BIT_ULL(pmc->idx);
if (pmc_is_pmi_enabled(pmc))
kvm_make_request(KVM_REQ_PMI, vcpu);
}
}
static inline bool cpl_is_matched(struct kvm_pmc *pmc)