[PATCH v2 7/9] KVM: arm/arm64: PMU: remove request-less vcpu kick

[Andrew Jones <drjones@redhat.com>]

Refactor PMU overflow handling in order to remove the request-less
vcpu kick.  Now, since kvm_vgic_inject_irq() uses vcpu requests,
there should be no chance that a kick sent at just the wrong time
(between the VCPU's call to kvm_pmu_flush_hwstate() and before it
enters guest mode) results in a failure for the guest to see updated
GIC state until its next exit some time later for some other reason.

Signed-off-by: Andrew Jones <drjones@redhat.com>
---
 virt/kvm/arm/pmu.c | 29 +++++++++++++++--------------
 1 file changed, 15 insertions(+), 14 deletions(-)

diff --git a/virt/kvm/arm/pmu.c b/virt/kvm/arm/pmu.c
index 69ccce308458..9d725f3afb11 100644
--- a/virt/kvm/arm/pmu.c
+++ b/virt/kvm/arm/pmu.c
@@ -203,6 +203,19 @@ static u64 kvm_pmu_overflow_status(struct kvm_vcpu *vcpu)
 	return reg;
 }
 
+static void kvm_pmu_check_overflow(struct kvm_vcpu *vcpu)
+{
+	struct kvm_pmu *pmu = &vcpu->arch.pmu;
+	bool overflow;
+
+	overflow = !!kvm_pmu_overflow_status(vcpu);
+	if (pmu->irq_level != overflow) {
+		pmu->irq_level = overflow;
+		kvm_vgic_inject_irq(vcpu->kvm, vcpu->vcpu_id,
+				    pmu->irq_num, overflow);
+	}
+}
+
 /**
  * kvm_pmu_overflow_set - set PMU overflow interrupt
  * @vcpu: The vcpu pointer
@@ -210,31 +223,19 @@ static u64 kvm_pmu_overflow_status(struct kvm_vcpu *vcpu)
  */
 void kvm_pmu_overflow_set(struct kvm_vcpu *vcpu, u64 val)
 {
-	u64 reg;
-
 	if (val == 0)
 		return;
 
 	vcpu_sys_reg(vcpu, PMOVSSET_EL0) |= val;
-	reg = kvm_pmu_overflow_status(vcpu);
-	if (reg != 0)
-		kvm_vcpu_kick(vcpu);
+	kvm_pmu_check_overflow(vcpu);
 }
 
 static void kvm_pmu_update_state(struct kvm_vcpu *vcpu)
 {
-	struct kvm_pmu *pmu = &vcpu->arch.pmu;
-	bool overflow;
-
 	if (!kvm_arm_pmu_v3_ready(vcpu))
 		return;
 
-	overflow = !!kvm_pmu_overflow_status(vcpu);
-	if (pmu->irq_level != overflow) {
-		pmu->irq_level = overflow;
-		kvm_vgic_inject_irq(vcpu->kvm, vcpu->vcpu_id,
-				    pmu->irq_num, overflow);
-	}
+	kvm_pmu_check_overflow(vcpu);
 }
 
 /**
-- 
2.9.3