4 files changed, 88 insertions, 0 deletions

diff --git a/virt/kvm/arm/vgic/vgic-v2.c b/virt/kvm/arm/vgic/vgic-v2.c
index 80897102da26..c32d7b93ffd1 100644
--- a/virt/kvm/arm/vgic/vgic-v2.c
+++ b/virt/kvm/arm/vgic/vgic-v2.c
@@ -105,6 +105,26 @@ void vgic_v2_fold_lr_state(struct kvm_vcpu *vcpu)
 				irq->pending_latch = false;
 		}
 
+		/*
+		 * 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.
+		 *
+		 * 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.
+		 */
+		if (vgic_irq_is_mapped_level(irq) && (val & GICH_LR_PENDING_BIT)) {
+			irq->line_level = vgic_get_phys_line_level(irq);
+
+			if (!irq->line_level)
+				vgic_irq_set_phys_active(irq, false);
+		}
+
 		spin_unlock_irqrestore(&irq->irq_lock, flags);
 		vgic_put_irq(vcpu->kvm, irq);
 	}
@@ -162,6 +182,15 @@ void vgic_v2_populate_lr(struct kvm_vcpu *vcpu, struct vgic_irq *irq, int lr)
 			val |= GICH_LR_EOI;
 	}
 
+	/*
+	 * Level-triggered mapped IRQs are special because we only observe
+	 * rising edges as input to the VGIC.  We therefore lower the line
+	 * level here, so that we can take new virtual IRQs.  See
+	 * vgic_v2_fold_lr_state for more info.
+	 */
+	if (vgic_irq_is_mapped_level(irq) && (val & GICH_LR_PENDING_BIT))
+		irq->line_level = false;
+
 	/* The GICv2 LR only holds five bits of priority. */
 	val |= (irq->priority >> 3) << GICH_LR_PRIORITY_SHIFT;
 
diff --git a/virt/kvm/arm/vgic/vgic-v3.c b/virt/kvm/arm/vgic/vgic-v3.c
index f47e8481fa45..6b329414e57a 100644
--- a/virt/kvm/arm/vgic/vgic-v3.c
+++ b/virt/kvm/arm/vgic/vgic-v3.c
@@ -96,6 +96,26 @@ void vgic_v3_fold_lr_state(struct kvm_vcpu *vcpu)
 				irq->pending_latch = false;
 		}
 
+		/*
+		 * 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.
+		 *
+		 * 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.
+		 */
+		if (vgic_irq_is_mapped_level(irq) && (val & ICH_LR_PENDING_BIT)) {
+			irq->line_level = vgic_get_phys_line_level(irq);
+
+			if (!irq->line_level)
+				vgic_irq_set_phys_active(irq, false);
+		}
+
 		spin_unlock_irqrestore(&irq->irq_lock, flags);
 		vgic_put_irq(vcpu->kvm, irq);
 	}
@@ -146,6 +166,15 @@ void vgic_v3_populate_lr(struct kvm_vcpu *vcpu, struct vgic_irq *irq, int lr)
 	}
 
 	/*
+	 * Level-triggered mapped IRQs are special because we only observe
+	 * rising edges as input to the VGIC.  We therefore lower the line
+	 * level here, so that we can take new virtual IRQs.  See
+	 * vgic_v3_fold_lr_state for more info.
+	 */
+	if (vgic_irq_is_mapped_level(irq) && (val & ICH_LR_PENDING_BIT))
+		irq->line_level = false;
+
+	/*
 	 * We currently only support Group1 interrupts, which is a
 	 * known defect. This needs to be addressed at some point.
 	 */
diff --git a/virt/kvm/arm/vgic/vgic.c b/virt/kvm/arm/vgic/vgic.c
index ecb8e25f5fe5..4318e9edd075 100644
--- a/virt/kvm/arm/vgic/vgic.c
+++ b/virt/kvm/arm/vgic/vgic.c
@@ -144,6 +144,29 @@ void vgic_put_irq(struct kvm *kvm, struct vgic_irq *irq)
 	kfree(irq);
 }
 
+/* Get the input level of a mapped IRQ directly from the physical GIC */
+bool vgic_get_phys_line_level(struct vgic_irq *irq)
+{
+	bool line_level;
+
+	BUG_ON(!irq->hw);
+
+	WARN_ON(irq_get_irqchip_state(irq->host_irq,
+				      IRQCHIP_STATE_PENDING,
+				      &line_level));
+	return line_level;
+}
+
+/* Set/Clear the physical active state */
+void vgic_irq_set_phys_active(struct vgic_irq *irq, bool active)
+{
+
+	BUG_ON(!irq->hw);
+	WARN_ON(irq_set_irqchip_state(irq->host_irq,
+				      IRQCHIP_STATE_ACTIVE,
+				      active));
+}
+
 /**
  * kvm_vgic_target_oracle - compute the target vcpu for an irq
  *
diff --git a/virt/kvm/arm/vgic/vgic.h b/virt/kvm/arm/vgic/vgic.h
index efbcf8f96f9c..d0787983a357 100644
--- a/virt/kvm/arm/vgic/vgic.h
+++ b/virt/kvm/arm/vgic/vgic.h
@@ -104,6 +104,11 @@ static inline bool irq_is_pending(struct vgic_irq *irq)
 		return irq->pending_latch || irq->line_level;
 }
 
+static inline bool vgic_irq_is_mapped_level(struct vgic_irq *irq)
+{
+	return irq->config == VGIC_CONFIG_LEVEL && irq->hw;
+}
+
 /*
  * This struct provides an intermediate representation of the fields contained
  * in the GICH_VMCR and ICH_VMCR registers, such that code exporting the GIC
@@ -140,6 +145,8 @@ vgic_get_mmio_region(struct kvm_vcpu *vcpu, struct vgic_io_device *iodev,
 struct vgic_irq *vgic_get_irq(struct kvm *kvm, struct kvm_vcpu *vcpu,
 			      u32 intid);
 void vgic_put_irq(struct kvm *kvm, struct vgic_irq *irq);
+bool vgic_get_phys_line_level(struct vgic_irq *irq);
+void vgic_irq_set_phys_active(struct vgic_irq *irq, bool active);
 bool vgic_queue_irq_unlock(struct kvm *kvm, struct vgic_irq *irq,
 			   unsigned long flags);
 void vgic_kick_vcpus(struct kvm *kvm);