KVM: x86/pmu: Add macros to iterate over all PMCs given a bitmap

Add and use kvm_for_each_pmc() to dedup a variety of open coded for-loops
that iterate over valid PMCs given a bitmap (and because seeing checkpatch
whine about bad macro style is always amusing).

No functional change intended.

Link: https://lore.kernel.org/r/20231110022857.1273836-6-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>

Author: sean-jc

arch/x86/kvm/pmu.c

@@ -493,6 +493,7 @@ void kvm_pmu_handle_event(struct kvm_vcpu *vcpu)
 {
 	DECLARE_BITMAP(bitmap, X86_PMC_IDX_MAX);
 	struct kvm_pmu *pmu = vcpu_to_pmu(vcpu);
+	struct kvm_pmc *pmc;
 	int bit;
 
 	bitmap_copy(bitmap, pmu->reprogram_pmi, X86_PMC_IDX_MAX);
@@ -505,12 +506,7 @@ void kvm_pmu_handle_event(struct kvm_vcpu *vcpu)
 	BUILD_BUG_ON(sizeof(bitmap) != sizeof(atomic64_t));
 	atomic64_andnot(*(s64 *)bitmap, &pmu->__reprogram_pmi);
 
-	for_each_set_bit(bit, bitmap, X86_PMC_IDX_MAX) {
-		struct kvm_pmc *pmc = kvm_pmc_idx_to_pmc(pmu, bit);
-
-		if (unlikely(!pmc))
-			continue;
-
+	kvm_for_each_pmc(pmu, pmc, bit, bitmap) {
 		/*
 		 * If reprogramming fails, e.g. due to contention, re-set the
 		 * regprogram bit set, i.e. opportunistically try again on the
@@ -730,11 +726,7 @@ static void kvm_pmu_reset(struct kvm_vcpu *vcpu)
 
 	bitmap_zero(pmu->reprogram_pmi, X86_PMC_IDX_MAX);
 
-	for_each_set_bit(i, pmu->all_valid_pmc_idx, X86_PMC_IDX_MAX) {
-		pmc = kvm_pmc_idx_to_pmc(pmu, i);
-		if (!pmc)
-			continue;
-
+	kvm_for_each_pmc(pmu, pmc, i, pmu->all_valid_pmc_idx) {
 		pmc_stop_counter(pmc);
 		pmc->counter = 0;
 		pmc->emulated_counter = 0;
@@ -806,10 +798,8 @@ void kvm_pmu_cleanup(struct kvm_vcpu *vcpu)
 	bitmap_andnot(bitmask, pmu->all_valid_pmc_idx,
 		      pmu->pmc_in_use, X86_PMC_IDX_MAX);
 
-	for_each_set_bit(i, bitmask, X86_PMC_IDX_MAX) {
-		pmc = kvm_pmc_idx_to_pmc(pmu, i);
-
-		if (pmc && pmc->perf_event && !pmc_speculative_in_use(pmc))
+	kvm_for_each_pmc(pmu, pmc, i, bitmask) {
+		if (pmc->perf_event && !pmc_speculative_in_use(pmc))
 			pmc_stop_counter(pmc);
 	}
 
@@ -861,10 +851,8 @@ void kvm_pmu_trigger_event(struct kvm_vcpu *vcpu, u64 perf_hw_id)
 	struct kvm_pmc *pmc;
 	int i;
 
-	for_each_set_bit(i, pmu->all_valid_pmc_idx, X86_PMC_IDX_MAX) {
-		pmc = kvm_pmc_idx_to_pmc(pmu, i);
-
-		if (!pmc || !pmc_event_is_allowed(pmc))
+	kvm_for_each_pmc(pmu, pmc, i, pmu->all_valid_pmc_idx) {
+		if (!pmc_event_is_allowed(pmc))
 			continue;
 
 		/* Ignore checks for edge detect, pin control, invert and CMASK bits */

arch/x86/kvm/pmu.h

@@ -83,6 +83,12 @@ static inline struct kvm_pmc *kvm_pmc_idx_to_pmc(struct kvm_pmu *pmu, int idx)
 	return NULL;
 }
 
+#define kvm_for_each_pmc(pmu, pmc, i, bitmap)			\
+	for_each_set_bit(i, bitmap, X86_PMC_IDX_MAX)		\
+		if (!(pmc = kvm_pmc_idx_to_pmc(pmu, i)))	\
+			continue;				\
+		else						\
+
 static inline u64 pmc_bitmask(struct kvm_pmc *pmc)
 {
 	struct kvm_pmu *pmu = pmc_to_pmu(pmc);

arch/x86/kvm/vmx/pmu_intel.c

@@ -704,11 +704,8 @@ void intel_pmu_cross_mapped_check(struct kvm_pmu *pmu)
 	struct kvm_pmc *pmc = NULL;
 	int bit, hw_idx;
 
-	for_each_set_bit(bit, (unsigned long *)&pmu->global_ctrl,
-			 X86_PMC_IDX_MAX) {
-		pmc = kvm_pmc_idx_to_pmc(pmu, bit);
-
-		if (!pmc || !pmc_speculative_in_use(pmc) ||
+	kvm_for_each_pmc(pmu, pmc, bit, (unsigned long *)&pmu->global_ctrl) {
+		if (!pmc_speculative_in_use(pmc) ||
 		    !pmc_is_globally_enabled(pmc) || !pmc->perf_event)
 			continue;