KVM: arm/arm64: arch_timer: Preserve physical dist. active state on LR.active

We were incorrectly removing the active state from the physical
distributor on the timer interrupt when the timer output level was
deasserted.  We shouldn't be doing this without considering the virtual
interrupt's active state, because the architecture requires that when an
LR has the HW bit set and the pending or active bits set, then the
physical interrupt must also have the corresponding bits set.

This addresses an issue where we have been observing an inconsistency
between the LR state and the physical distributor state where the LR
state was active and the physical distributor was not active, which
shouldn't happen.

Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>

1 files changed, 22 insertions, 12 deletions

diff --git a/virt/kvm/arm/vgic.c b/virt/kvm/arm/vgic.c
index 533538385d5d..97e2c088e1e9 100644
--- a/virt/kvm/arm/vgic.c
+++ b/virt/kvm/arm/vgic.c
@@ -1096,6 +1096,27 @@ static void vgic_retire_lr(int lr_nr, struct kvm_vcpu *vcpu)
 	vgic_set_lr(vcpu, lr_nr, vlr);
 }
 
+static bool dist_active_irq(struct kvm_vcpu *vcpu)
+{
+	struct vgic_dist *dist = &vcpu->kvm->arch.vgic;
+
+	return test_bit(vcpu->vcpu_id, dist->irq_active_on_cpu);
+}
+
+bool kvm_vgic_map_is_active(struct kvm_vcpu *vcpu, struct irq_phys_map *map)
+{
+	int i;
+
+	for (i = 0; i < vcpu->arch.vgic_cpu.nr_lr; i++) {
+		struct vgic_lr vlr = vgic_get_lr(vcpu, i);
+
+		if (vlr.irq == map->virt_irq && vlr.state & LR_STATE_ACTIVE)
+			return true;
+	}
+
+	return dist_active_irq(vcpu);
+}
+
 /*
  * An interrupt may have been disabled after being made pending on the
  * CPU interface (the classic case is a timer running while we're
@@ -1248,7 +1269,7 @@ static void __kvm_vgic_flush_hwstate(struct kvm_vcpu *vcpu)
 	 * may have been serviced from another vcpu. In all cases,
 	 * move along.
 	 */
-	if (!kvm_vgic_vcpu_pending_irq(vcpu) && !kvm_vgic_vcpu_active_irq(vcpu))
+	if (!kvm_vgic_vcpu_pending_irq(vcpu) && !dist_active_irq(vcpu))
 		goto epilog;
 
 	/* SGIs */
@@ -1479,17 +1500,6 @@ int kvm_vgic_vcpu_pending_irq(struct kvm_vcpu *vcpu)
 	return test_bit(vcpu->vcpu_id, dist->irq_pending_on_cpu);
 }
 
-int kvm_vgic_vcpu_active_irq(struct kvm_vcpu *vcpu)
-{
-	struct vgic_dist *dist = &vcpu->kvm->arch.vgic;
-
-	if (!irqchip_in_kernel(vcpu->kvm))
-		return 0;
-
-	return test_bit(vcpu->vcpu_id, dist->irq_active_on_cpu);
-}
-
-
 void vgic_kick_vcpus(struct kvm *kvm)
 {
 	struct kvm_vcpu *vcpu;