1 files changed, 38 insertions, 1 deletions

diff --git a/arch/arm64/kvm/vgic/vgic.c b/arch/arm64/kvm/vgic/vgic.c
index 111bff47e471..5dad4996cfb2 100644
--- a/arch/arm64/kvm/vgic/vgic.c
+++ b/arch/arm64/kvm/vgic/vgic.c
@@ -106,7 +106,6 @@ struct vgic_irq *vgic_get_irq(struct kvm *kvm, struct kvm_vcpu *vcpu,
 	if (intid >= VGIC_MIN_LPI)
 		return vgic_get_lpi(kvm, intid);
 
-	WARN(1, "Looking up struct vgic_irq for reserved INTID");
 	return NULL;
 }
 
@@ -1022,3 +1021,41 @@ bool kvm_vgic_map_is_active(struct kvm_vcpu *vcpu, unsigned int vintid)
 
 	return map_is_active;
 }
+
+/*
+ * Level-triggered mapped IRQs are special because we only observe rising
+ * edges as input to the VGIC.
+ *
+ * If the guest never acked the interrupt we have to sample the physical
+ * line and set the line level, because the device state could have changed
+ * or we simply need to process the still pending interrupt later.
+ *
+ * We could also have entered the guest with the interrupt active+pending.
+ * On the next exit, we need to re-evaluate the pending state, as it could
+ * otherwise result in a spurious interrupt by injecting a now potentially
+ * stale pending state.
+ *
+ * If this causes us to lower the level, we have to also clear the physical
+ * active state, since we will otherwise never be told when the interrupt
+ * becomes asserted again.
+ *
+ * Another case is when the interrupt requires a helping hand on
+ * deactivation (no HW deactivation, for example).
+ */
+void vgic_irq_handle_resampling(struct vgic_irq *irq,
+				bool lr_deactivated, bool lr_pending)
+{
+	if (vgic_irq_is_mapped_level(irq)) {
+		bool resample = false;
+
+		if (unlikely(vgic_irq_needs_resampling(irq))) {
+			resample = !(irq->active || irq->pending_latch);
+		} else if (lr_pending || (lr_deactivated && irq->line_level)) {
+			irq->line_level = vgic_get_phys_line_level(irq);
+			resample = !irq->line_level;
+		}
+
+		if (resample)
+			vgic_irq_set_phys_active(irq, false);
+	}
+}