1 files changed, 110 insertions, 9 deletions

diff --git a/virt/kvm/arm/vgic/vgic.c b/virt/kvm/arm/vgic/vgic.c
index 69b61abefa19..39f3358c6d91 100644
--- a/virt/kvm/arm/vgic/vgic.c
+++ b/virt/kvm/arm/vgic/vgic.c
@@ -33,10 +33,17 @@ struct vgic_global __section(.hyp.text) kvm_vgic_global_state;
 
 /*
  * Locking order is always:
- *   vgic_cpu->ap_list_lock
- *     vgic_irq->irq_lock
+ * its->cmd_lock (mutex)
+ *   its->its_lock (mutex)
+ *     vgic_cpu->ap_list_lock
+ *       kvm->lpi_list_lock
+ *         vgic_irq->irq_lock
  *
- * (that is, always take the ap_list_lock before the struct vgic_irq lock).
+ * If you need to take multiple locks, always take the upper lock first,
+ * then the lower ones, e.g. first take the its_lock, then the irq_lock.
+ * If you are already holding a lock and need to take a higher one, you
+ * have to drop the lower ranking lock first and re-aquire it after having
+ * taken the upper one.
  *
  * When taking more than one ap_list_lock at the same time, always take the
  * lowest numbered VCPU's ap_list_lock first, so:
@@ -45,6 +52,41 @@ struct vgic_global __section(.hyp.text) kvm_vgic_global_state;
  *     spin_lock(vcpuY->arch.vgic_cpu.ap_list_lock);
  */
 
+/*
+ * Iterate over the VM's list of mapped LPIs to find the one with a
+ * matching interrupt ID and return a reference to the IRQ structure.
+ */
+static struct vgic_irq *vgic_get_lpi(struct kvm *kvm, u32 intid)
+{
+	struct vgic_dist *dist = &kvm->arch.vgic;
+	struct vgic_irq *irq = NULL;
+
+	spin_lock(&dist->lpi_list_lock);
+
+	list_for_each_entry(irq, &dist->lpi_list_head, lpi_list) {
+		if (irq->intid != intid)
+			continue;
+
+		/*
+		 * This increases the refcount, the caller is expected to
+		 * call vgic_put_irq() later once it's finished with the IRQ.
+		 */
+		vgic_get_irq_kref(irq);
+		goto out_unlock;
+	}
+	irq = NULL;
+
+out_unlock:
+	spin_unlock(&dist->lpi_list_lock);
+
+	return irq;
+}
+
+/*
+ * This looks up the virtual interrupt ID to get the corresponding
+ * struct vgic_irq. It also increases the refcount, so any caller is expected
+ * to call vgic_put_irq() once it's finished with this IRQ.
+ */
 struct vgic_irq *vgic_get_irq(struct kvm *kvm, struct kvm_vcpu *vcpu,
 			      u32 intid)
 {
@@ -56,14 +98,43 @@ struct vgic_irq *vgic_get_irq(struct kvm *kvm, struct kvm_vcpu *vcpu,
 	if (intid <= VGIC_MAX_SPI)
 		return &kvm->arch.vgic.spis[intid - VGIC_NR_PRIVATE_IRQS];
 
-	/* LPIs are not yet covered */
+	/* LPIs */
 	if (intid >= VGIC_MIN_LPI)
-		return NULL;
+		return vgic_get_lpi(kvm, intid);
 
 	WARN(1, "Looking up struct vgic_irq for reserved INTID");
 	return NULL;
 }
 
+/*
+ * We can't do anything in here, because we lack the kvm pointer to
+ * lock and remove the item from the lpi_list. So we keep this function
+ * empty and use the return value of kref_put() to trigger the freeing.
+ */
+static void vgic_irq_release(struct kref *ref)
+{
+}
+
+void vgic_put_irq(struct kvm *kvm, struct vgic_irq *irq)
+{
+	struct vgic_dist *dist;
+
+	if (irq->intid < VGIC_MIN_LPI)
+		return;
+
+	if (!kref_put(&irq->refcount, vgic_irq_release))
+		return;
+
+	dist = &kvm->arch.vgic;
+
+	spin_lock(&dist->lpi_list_lock);
+	list_del(&irq->lpi_list);
+	dist->lpi_list_count--;
+	spin_unlock(&dist->lpi_list_lock);
+
+	kfree(irq);
+}
+
 /**
  * kvm_vgic_target_oracle - compute the target vcpu for an irq
  *
@@ -236,6 +307,11 @@ retry:
 		goto retry;
 	}
 
+	/*
+	 * Grab a reference to the irq to reflect the fact that it is
+	 * now in the ap_list.
+	 */
+	vgic_get_irq_kref(irq);
 	list_add_tail(&irq->ap_list, &vcpu->arch.vgic_cpu.ap_list_head);
 	irq->vcpu = vcpu;
 
@@ -269,14 +345,17 @@ static int vgic_update_irq_pending(struct kvm *kvm, int cpuid,
 	if (!irq)
 		return -EINVAL;
 
-	if (irq->hw != mapped_irq)
+	if (irq->hw != mapped_irq) {
+		vgic_put_irq(kvm, irq);
 		return -EINVAL;
+	}
 
 	spin_lock(&irq->irq_lock);
 
 	if (!vgic_validate_injection(irq, level)) {
 		/* Nothing to see here, move along... */
 		spin_unlock(&irq->irq_lock);
+		vgic_put_irq(kvm, irq);
 		return 0;
 	}
 
@@ -288,6 +367,7 @@ static int vgic_update_irq_pending(struct kvm *kvm, int cpuid,
 	}
 
 	vgic_queue_irq_unlock(kvm, irq);
+	vgic_put_irq(kvm, irq);
 
 	return 0;
 }
@@ -330,25 +410,28 @@ int kvm_vgic_map_phys_irq(struct kvm_vcpu *vcpu, u32 virt_irq, u32 phys_irq)
 	irq->hwintid = phys_irq;
 
 	spin_unlock(&irq->irq_lock);
+	vgic_put_irq(vcpu->kvm, irq);
 
 	return 0;
 }
 
 int kvm_vgic_unmap_phys_irq(struct kvm_vcpu *vcpu, unsigned int virt_irq)
 {
-	struct vgic_irq *irq = vgic_get_irq(vcpu->kvm, vcpu, virt_irq);
-
-	BUG_ON(!irq);
+	struct vgic_irq *irq;
 
 	if (!vgic_initialized(vcpu->kvm))
 		return -EAGAIN;
 
+	irq = vgic_get_irq(vcpu->kvm, vcpu, virt_irq);
+	BUG_ON(!irq);
+
 	spin_lock(&irq->irq_lock);
 
 	irq->hw = false;
 	irq->hwintid = 0;
 
 	spin_unlock(&irq->irq_lock);
+	vgic_put_irq(vcpu->kvm, irq);
 
 	return 0;
 }
@@ -386,6 +469,15 @@ retry:
 			list_del(&irq->ap_list);
 			irq->vcpu = NULL;
 			spin_unlock(&irq->irq_lock);
+
+			/*
+			 * This vgic_put_irq call matches the
+			 * vgic_get_irq_kref in vgic_queue_irq_unlock,
+			 * where we added the LPI to the ap_list. As
+			 * we remove the irq from the list, we drop
+			 * also drop the refcount.
+			 */
+			vgic_put_irq(vcpu->kvm, irq);
 			continue;
 		}
 
@@ -614,6 +706,15 @@ bool kvm_vgic_map_is_active(struct kvm_vcpu *vcpu, unsigned int virt_irq)
 	spin_lock(&irq->irq_lock);
 	map_is_active = irq->hw && irq->active;
 	spin_unlock(&irq->irq_lock);
+	vgic_put_irq(vcpu->kvm, irq);
 
 	return map_is_active;
 }
+
+int kvm_send_userspace_msi(struct kvm *kvm, struct kvm_msi *msi)
+{
+	if (vgic_has_its(kvm))
+		return vgic_its_inject_msi(kvm, msi);
+	else
+		return -ENODEV;
+}