KVM: x86/pmu: Prevent the PMU from counting disallowed events

When counting "Instructions Retired" (0xc0) in a guest, KVM will
occasionally increment the PMU counter regardless of if that event is
being filtered. This is because some PMU events are incremented via
kvm_pmu_trigger_event(), which doesn't know about the event filter. Add
the event filter to kvm_pmu_trigger_event(), so events that are
disallowed do not increment their counters.

Fixes: 9cd803d496e7 ("KVM: x86: Update vPMCs when retiring instructions")
Signed-off-by: Aaron Lewis <aaronlewis@google.com>
Reviewed-by: Like Xu <likexu@tencent.com>
Link: https://lore.kernel.org/r/20230307141400.1486314-2-aaronlewis@google.com
[sean: prepend "pmc" to the new function]
Signed-off-by: Sean Christopherson <seanjc@google.com>

diff --git a/arch/x86/kvm/pmu.c b/arch/x86/kvm/pmu.c
index 2226db9..597a8f8 100644 (file)
--- a/arch/x86/kvm/pmu.c
+++ b/arch/x86/kvm/pmu.c
@@ -400,6 +400,12 @@ static bool check_pmu_event_filter(struct kvm_pmc *pmc)
        return is_fixed_event_allowed(filter, pmc->idx);
 }
 
+static bool pmc_event_is_allowed(struct kvm_pmc *pmc)
+{
+       return pmc_is_globally_enabled(pmc) && pmc_speculative_in_use(pmc) &&
+              check_pmu_event_filter(pmc);
+}
+
 static void reprogram_counter(struct kvm_pmc *pmc)
 {
        struct kvm_pmu *pmu = pmc_to_pmu(pmc);
@@ -409,10 +415,7 @@ static void reprogram_counter(struct kvm_pmc *pmc)
 
        pmc_pause_counter(pmc);
 
-       if (!pmc_speculative_in_use(pmc) || !pmc_is_globally_enabled(pmc))
-               goto reprogram_complete;
-
-       if (!check_pmu_event_filter(pmc))
+       if (!pmc_event_is_allowed(pmc))
                goto reprogram_complete;
 
        if (pmc->counter < pmc->prev_counter)
@@ -688,7 +691,7 @@ void kvm_pmu_trigger_event(struct kvm_vcpu *vcpu, u64 perf_hw_id)
        for_each_set_bit(i, pmu->all_valid_pmc_idx, X86_PMC_IDX_MAX) {
                pmc = static_call(kvm_x86_pmu_pmc_idx_to_pmc)(pmu, i);
 
-               if (!pmc || !pmc_is_globally_enabled(pmc) || !pmc_speculative_in_use(pmc))
+               if (!pmc || !pmc_event_is_allowed(pmc))
                        continue;
 
                /* Ignore checks for edge detect, pin control, invert and CMASK bits */