KVM: x86/pmu: Extract check_pmu_event_filter() handling both GP and fixed counters

Checking the kvm->arch.pmu_event_filter policy in both gp and fixed
code paths was somewhat redundant, so common parts can be extracted,
which reduces code footprint and improves readability.
Signed-off-by: Like Xu <likexu@tencent.com>
Reviewed-by: Wanpeng Li <wanpengli@tencent.com>
Message-Id: <20220518132512.37864-3-likexu@tencent.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

arch/x86/kvm/pmu.c

@@ -250,14 +250,44 @@ static int cmp_u64(const void *pa, const void *pb)
 	return (a > b) - (a < b);
 }
 
+static bool check_pmu_event_filter(struct kvm_pmc *pmc)
+{
+	struct kvm_pmu_event_filter *filter;
+	struct kvm *kvm = pmc->vcpu->kvm;
+	bool allow_event = true;
+	__u64 key;
+	int idx;
+
+	filter = srcu_dereference(kvm->arch.pmu_event_filter, &kvm->srcu);
+	if (!filter)
+		goto out;
+
+	if (pmc_is_gp(pmc)) {
+		key = pmc->eventsel & AMD64_RAW_EVENT_MASK_NB;
+		if (bsearch(&key, filter->events, filter->nevents,
+			    sizeof(__u64), cmp_u64))
+			allow_event = filter->action == KVM_PMU_EVENT_ALLOW;
+		else
+			allow_event = filter->action == KVM_PMU_EVENT_DENY;
+	} else {
+		idx = pmc->idx - INTEL_PMC_IDX_FIXED;
+		if (filter->action == KVM_PMU_EVENT_DENY &&
+		    test_bit(idx, (ulong *)&filter->fixed_counter_bitmap))
+			allow_event = false;
+		if (filter->action == KVM_PMU_EVENT_ALLOW &&
+		    !test_bit(idx, (ulong *)&filter->fixed_counter_bitmap))
+			allow_event = false;
+	}
+
+out:
+	return allow_event;
+}
+
 void reprogram_gp_counter(struct kvm_pmc *pmc, u64 eventsel)
 {
 	u64 config;
 	u32 type = PERF_TYPE_RAW;
-	struct kvm *kvm = pmc->vcpu->kvm;
-	struct kvm_pmu_event_filter *filter;
-	struct kvm_pmu *pmu = vcpu_to_pmu(pmc->vcpu);
-	bool allow_event = true;
+	struct kvm_pmu *pmu = pmc_to_pmu(pmc);
 
 	if (eventsel & ARCH_PERFMON_EVENTSEL_PIN_CONTROL)
 		printk_once("kvm pmu: pin control bit is ignored\n");
@@ -269,17 +299,7 @@ void reprogram_gp_counter(struct kvm_pmc *pmc, u64 eventsel)
 	if (!(eventsel & ARCH_PERFMON_EVENTSEL_ENABLE) || !pmc_is_enabled(pmc))
 		return;
 
-	filter = srcu_dereference(kvm->arch.pmu_event_filter, &kvm->srcu);
-	if (filter) {
-		__u64 key = eventsel & AMD64_RAW_EVENT_MASK_NB;
-
-		if (bsearch(&key, filter->events, filter->nevents,
-			    sizeof(__u64), cmp_u64))
-			allow_event = filter->action == KVM_PMU_EVENT_ALLOW;
-		else
-			allow_event = filter->action == KVM_PMU_EVENT_DENY;
-	}
-	if (!allow_event)
+	if (!check_pmu_event_filter(pmc))
 		return;
 
 	if (!(eventsel & (ARCH_PERFMON_EVENTSEL_EDGE |
@@ -312,23 +332,14 @@ void reprogram_fixed_counter(struct kvm_pmc *pmc, u8 ctrl, int idx)
 {
 	unsigned en_field = ctrl & 0x3;
 	bool pmi = ctrl & 0x8;
-	struct kvm_pmu_event_filter *filter;
-	struct kvm *kvm = pmc->vcpu->kvm;
 
 	pmc_pause_counter(pmc);
 
 	if (!en_field || !pmc_is_enabled(pmc))
 		return;
 
-	filter = srcu_dereference(kvm->arch.pmu_event_filter, &kvm->srcu);
-	if (filter) {
-		if (filter->action == KVM_PMU_EVENT_DENY &&
-		    test_bit(idx, (ulong *)&filter->fixed_counter_bitmap))
+	if (!check_pmu_event_filter(pmc))
 		return;
-		if (filter->action == KVM_PMU_EVENT_ALLOW &&
-		    !test_bit(idx, (ulong *)&filter->fixed_counter_bitmap))
-			return;
-	}
 
 	if (pmc->current_config == (u64)ctrl && pmc_resume_counter(pmc))
 		return;