KVM: x86/pmu: Reuse pmc_perf_hw_id() and drop find_fixed_event()

Since we set the same semantic event value for the fixed counter in
pmc->eventsel, returning the perf_hw_id for the fixed counter via
find_fixed_event() can be painlessly replaced by pmc_perf_hw_id()
with the help of pmc_is_fixed() check.
Signed-off-by: Like Xu <likexu@tencent.com>
Message-Id: <20211130074221.93635-4-likexu@tencent.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

arch/x86/kvm/pmu.c

@@ -262,7 +262,7 @@ void reprogram_fixed_counter(struct kvm_pmc *pmc, u8 ctrl, int idx)
 
 	pmc->current_config = (u64)ctrl;
 	pmc_reprogram_counter(pmc, PERF_TYPE_HARDWARE,
-			      kvm_x86_ops.pmu_ops->find_fixed_event(idx),
+			      kvm_x86_ops.pmu_ops->pmc_perf_hw_id(pmc),
 			      !(en_field & 0x2), /* exclude user */
 			      !(en_field & 0x1), /* exclude kernel */
 			      pmi, false, false);

arch/x86/kvm/pmu.h

@@ -25,7 +25,6 @@ struct kvm_event_hw_type_mapping {
 
 struct kvm_pmu_ops {
 	unsigned int (*pmc_perf_hw_id)(struct kvm_pmc *pmc);
-	unsigned (*find_fixed_event)(int idx);
 	bool (*pmc_is_enabled)(struct kvm_pmc *pmc);
 	struct kvm_pmc *(*pmc_idx_to_pmc)(struct kvm_pmu *pmu, int pmc_idx);
 	struct kvm_pmc *(*rdpmc_ecx_to_pmc)(struct kvm_vcpu *vcpu,

arch/x86/kvm/svm/pmu.c

@@ -144,6 +144,10 @@ static unsigned int amd_pmc_perf_hw_id(struct kvm_pmc *pmc)
 	u8 unit_mask = (pmc->eventsel & ARCH_PERFMON_EVENTSEL_UMASK) >> 8;
 	int i;
 
+	/* return PERF_COUNT_HW_MAX as AMD doesn't have fixed events */
+	if (WARN_ON(pmc_is_fixed(pmc)))
+		return PERF_COUNT_HW_MAX;
+
 	for (i = 0; i < ARRAY_SIZE(amd_event_mapping); i++)
 		if (amd_event_mapping[i].eventsel == event_select
 		    && amd_event_mapping[i].unit_mask == unit_mask)
@@ -155,12 +159,6 @@ static unsigned int amd_pmc_perf_hw_id(struct kvm_pmc *pmc)
 	return amd_event_mapping[i].event_type;
 }
 
-/* return PERF_COUNT_HW_MAX as AMD doesn't have fixed events */
-static unsigned amd_find_fixed_event(int idx)
-{
-	return PERF_COUNT_HW_MAX;
-}
-
 /* check if a PMC is enabled by comparing it against global_ctrl bits. Because
  * AMD CPU doesn't have global_ctrl MSR, all PMCs are enabled (return TRUE).
  */
@@ -324,7 +322,6 @@ static void amd_pmu_reset(struct kvm_vcpu *vcpu)
 
 struct kvm_pmu_ops amd_pmu_ops = {
 	.pmc_perf_hw_id = amd_pmc_perf_hw_id,
-	.find_fixed_event = amd_find_fixed_event,
 	.pmc_is_enabled = amd_pmc_is_enabled,
 	.pmc_idx_to_pmc = amd_pmc_idx_to_pmc,
 	.rdpmc_ecx_to_pmc = amd_rdpmc_ecx_to_pmc,

arch/x86/kvm/vmx/pmu_intel.c

@@ -76,9 +76,9 @@ static unsigned int intel_pmc_perf_hw_id(struct kvm_pmc *pmc)
 	int i;
 
 	for (i = 0; i < ARRAY_SIZE(intel_arch_events); i++)
-		if (intel_arch_events[i].eventsel == event_select
-		    && intel_arch_events[i].unit_mask == unit_mask
-		    && (pmu->available_event_types & (1 << i)))
+		if (intel_arch_events[i].eventsel == event_select &&
+		    intel_arch_events[i].unit_mask == unit_mask &&
+		    (pmc_is_fixed(pmc) || pmu->available_event_types & (1 << i)))
 			break;
 
 	if (i == ARRAY_SIZE(intel_arch_events))
@@ -87,18 +87,6 @@ static unsigned int intel_pmc_perf_hw_id(struct kvm_pmc *pmc)
 	return intel_arch_events[i].event_type;
 }
 
-static unsigned intel_find_fixed_event(int idx)
-{
-	u32 event;
-	size_t size = ARRAY_SIZE(fixed_pmc_events);
-
-	if (WARN_ON_ONCE(idx >= size))
-		return PERF_COUNT_HW_MAX;
-
-	event = fixed_pmc_events[array_index_nospec(idx, size)];
-	return intel_arch_events[event].event_type;
-}
-
 /* check if a PMC is enabled by comparing it with globl_ctrl bits. */
 static bool intel_pmc_is_enabled(struct kvm_pmc *pmc)
 {
@@ -722,7 +710,6 @@ static void intel_pmu_cleanup(struct kvm_vcpu *vcpu)
 
 struct kvm_pmu_ops intel_pmu_ops = {
 	.pmc_perf_hw_id = intel_pmc_perf_hw_id,
-	.find_fixed_event = intel_find_fixed_event,
 	.pmc_is_enabled = intel_pmc_is_enabled,
 	.pmc_idx_to_pmc = intel_pmc_idx_to_pmc,
 	.rdpmc_ecx_to_pmc = intel_rdpmc_ecx_to_pmc,