1 files changed, 38 insertions, 9 deletions

diff --git a/drivers/xen/events.c b/drivers/xen/events.c
index 7523719bf8a4..7a55b292bf39 100644
--- a/drivers/xen/events.c
+++ b/drivers/xen/events.c
@@ -432,7 +432,8 @@ static int __must_check xen_allocate_irq_dynamic(void)
 
 	irq = irq_alloc_desc_from(first, -1);
 
-	xen_irq_init(irq);
+	if (irq >= 0)
+		xen_irq_init(irq);
 
 	return irq;
 }
@@ -713,7 +714,7 @@ int xen_bind_pirq_msi_to_irq(struct pci_dev *dev, struct msi_desc *msidesc,
 	mutex_lock(&irq_mapping_update_lock);
 
 	irq = xen_allocate_irq_dynamic();
-	if (irq == -1)
+	if (irq < 0)
 		goto out;
 
 	irq_set_chip_and_handler_name(irq, &xen_pirq_chip, handle_edge_irq,
@@ -729,7 +730,7 @@ out:
 error_irq:
 	mutex_unlock(&irq_mapping_update_lock);
 	xen_free_irq(irq);
-	return -1;
+	return ret;
 }
 #endif
 
@@ -779,7 +780,7 @@ int xen_irq_from_pirq(unsigned pirq)
 	mutex_lock(&irq_mapping_update_lock);
 
 	list_for_each_entry(info, &xen_irq_list_head, list) {
-		if (info == NULL || info->type != IRQT_PIRQ)
+		if (info->type != IRQT_PIRQ)
 			continue;
 		irq = info->irq;
 		if (info->u.pirq.pirq == pirq)
@@ -872,11 +873,32 @@ static int bind_interdomain_evtchn_to_irq(unsigned int remote_domain,
 	return err ? : bind_evtchn_to_irq(bind_interdomain.local_port);
 }
 
+static int find_virq(unsigned int virq, unsigned int cpu)
+{
+	struct evtchn_status status;
+	int port, rc = -ENOENT;
+
+	memset(&status, 0, sizeof(status));
+	for (port = 0; port <= NR_EVENT_CHANNELS; port++) {
+		status.dom = DOMID_SELF;
+		status.port = port;
+		rc = HYPERVISOR_event_channel_op(EVTCHNOP_status, &status);
+		if (rc < 0)
+			continue;
+		if (status.status != EVTCHNSTAT_virq)
+			continue;
+		if (status.u.virq == virq && status.vcpu == cpu) {
+			rc = port;
+			break;
+		}
+	}
+	return rc;
+}
 
 int bind_virq_to_irq(unsigned int virq, unsigned int cpu)
 {
 	struct evtchn_bind_virq bind_virq;
-	int evtchn, irq;
+	int evtchn, irq, ret;
 
 	mutex_lock(&irq_mapping_update_lock);
 
@@ -892,10 +914,16 @@ int bind_virq_to_irq(unsigned int virq, unsigned int cpu)
 
 		bind_virq.virq = virq;
 		bind_virq.vcpu = cpu;
-		if (HYPERVISOR_event_channel_op(EVTCHNOP_bind_virq,
-						&bind_virq) != 0)
-			BUG();
-		evtchn = bind_virq.port;
+		ret = HYPERVISOR_event_channel_op(EVTCHNOP_bind_virq,
+						&bind_virq);
+		if (ret == 0)
+			evtchn = bind_virq.port;
+		else {
+			if (ret == -EEXIST)
+				ret = find_virq(virq, cpu);
+			BUG_ON(ret < 0);
+			evtchn = ret;
+		}
 
 		xen_irq_info_virq_init(cpu, irq, evtchn, virq);
 
@@ -1670,6 +1698,7 @@ void __init xen_init_IRQ(void)
 
 	evtchn_to_irq = kcalloc(NR_EVENT_CHANNELS, sizeof(*evtchn_to_irq),
 				    GFP_KERNEL);
+	BUG_ON(!evtchn_to_irq);
 	for (i = 0; i < NR_EVENT_CHANNELS; i++)
 		evtchn_to_irq[i] = -1;