KVM: arm/arm64: PMU: remove request-less vcpu kick

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>
Reviewed-by: Christoffer Dall <cdall@linaro.org>
Signed-off-by: Christoffer Dall <cdall@linaro.org>

diff --git a/virt/kvm/arm/pmu.c b/virt/kvm/arm/pmu.c
index 4b43e7f..2451607 100644 (file)
--- a/virt/kvm/arm/pmu.c
+++ b/virt/kvm/arm/pmu.c
@@ -203,6 +203,23 @@ 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 = !!kvm_pmu_overflow_status(vcpu);
+
+       if (pmu->irq_level == overflow)
+               return;
+
+       pmu->irq_level = overflow;
+
+       if (likely(irqchip_in_kernel(vcpu->kvm))) {
+               int ret = kvm_vgic_inject_irq(vcpu->kvm, vcpu->vcpu_id,
+                                             pmu->irq_num, overflow);
+               WARN_ON(ret);
+       }
+}
+
 /**
  * kvm_pmu_overflow_set - set PMU overflow interrupt
  * @vcpu: The vcpu pointer
@@ -210,37 +227,18 @@ 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)
-               return;
-
-       pmu->irq_level = overflow;
-
-       if (likely(irqchip_in_kernel(vcpu->kvm))) {
-               int ret;
-               ret = kvm_vgic_inject_irq(vcpu->kvm, vcpu->vcpu_id,
-                                         pmu->irq_num, overflow);
-               WARN_ON(ret);
-       }
+       kvm_pmu_check_overflow(vcpu);
 }
 
 bool kvm_pmu_should_notify_user(struct kvm_vcpu *vcpu)