KVM: arm64: PMU: Reload when resetting

Replace kvm_pmu_vcpu_reset() with the generic PMU reloading mechanism to
ensure the consistency with system registers and to reduce code size.

Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Reviewed-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20250315-pmc-v5-5-ecee87dab216@daynix.com
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>

Author: akihikodaki

arch/arm64/kvm/pmu-emul.c

@@ -254,20 +254,6 @@ void kvm_pmu_vcpu_init(struct kvm_vcpu *vcpu)
 		pmu->pmc[i].idx = i;
 }
 
-/**
- * kvm_pmu_vcpu_reset - reset pmu state for cpu
- * @vcpu: The vcpu pointer
- *
- */
-void kvm_pmu_vcpu_reset(struct kvm_vcpu *vcpu)
-{
-	unsigned long mask = kvm_pmu_implemented_counter_mask(vcpu);
-	int i;
-
-	for_each_set_bit(i, &mask, 32)
-		kvm_pmu_stop_counter(kvm_vcpu_idx_to_pmc(vcpu, i));
-}
-
 /**
  * kvm_pmu_vcpu_destroy - free perf event of PMU for cpu
  * @vcpu: The vcpu pointer

arch/arm64/kvm/reset.c

@@ -196,9 +196,6 @@ void kvm_reset_vcpu(struct kvm_vcpu *vcpu)
 	vcpu->arch.reset_state.reset = false;
 	spin_unlock(&vcpu->arch.mp_state_lock);
 
-	/* Reset PMU outside of the non-preemptible section */
-	kvm_pmu_vcpu_reset(vcpu);
-
 	preempt_disable();
 	loaded = (vcpu->cpu != -1);
 	if (loaded)

arch/arm64/kvm/sys_regs.c

@@ -4480,6 +4480,9 @@ void kvm_reset_sys_regs(struct kvm_vcpu *vcpu)
 	}
 
 	set_bit(KVM_ARCH_FLAG_ID_REGS_INITIALIZED, &kvm->arch.flags);
+
+	if (kvm_vcpu_has_pmu(vcpu))
+		kvm_make_request(KVM_REQ_RELOAD_PMU, vcpu);
 }
 
 /**

include/kvm/arm_pmu.h

@@ -52,7 +52,6 @@ u64 kvm_pmu_implemented_counter_mask(struct kvm_vcpu *vcpu);
 u64 kvm_pmu_accessible_counter_mask(struct kvm_vcpu *vcpu);
 u64 kvm_pmu_get_pmceid(struct kvm_vcpu *vcpu, bool pmceid1);
 void kvm_pmu_vcpu_init(struct kvm_vcpu *vcpu);
-void kvm_pmu_vcpu_reset(struct kvm_vcpu *vcpu);
 void kvm_pmu_vcpu_destroy(struct kvm_vcpu *vcpu);
 void kvm_pmu_reprogram_counter_mask(struct kvm_vcpu *vcpu, u64 val);
 void kvm_pmu_flush_hwstate(struct kvm_vcpu *vcpu);
@@ -127,7 +126,6 @@ static inline u64 kvm_pmu_accessible_counter_mask(struct kvm_vcpu *vcpu)
 	return 0;
 }
 static inline void kvm_pmu_vcpu_init(struct kvm_vcpu *vcpu) {}
-static inline void kvm_pmu_vcpu_reset(struct kvm_vcpu *vcpu) {}
 static inline void kvm_pmu_vcpu_destroy(struct kvm_vcpu *vcpu) {}
 static inline void kvm_pmu_reprogram_counter_mask(struct kvm_vcpu *vcpu, u64 val) {}
 static inline void kvm_pmu_flush_hwstate(struct kvm_vcpu *vcpu) {}