xen/irq: Check if the PCI device is owned by a domain different than DOMID_SELF.

We check if there is a domain owner for the PCI device. In case of failure
(meaning no domain has registered for this device) we make DOMID_SELF the owner.

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
[v2: deal with rebasing on v2.6.37-1]
[v3: deal with rebasing on stable/irq.cleanup]
[v4: deal with rebasing on stable/irq.ween_of_nr_irqs]
[v5: deal with rebasing on v2.6.39-rc3]
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Acked-by: Xiantao Zhang <xiantao.zhang@intel.com>
diff --git a/drivers/xen/events.c b/drivers/xen/events.c
index 42d6c93..ac0e228 100644
--- a/drivers/xen/events.c
+++ b/drivers/xen/events.c
@@ -101,6 +101,7 @@
 			unsigned short gsi;
 			unsigned char vector;
 			unsigned char flags;
+			uint16_t domid;
 		} pirq;
 	} u;
 };
@@ -184,6 +185,7 @@
 				   unsigned short pirq,
 				   unsigned short gsi,
 				   unsigned short vector,
+				   uint16_t domid,
 				   unsigned char flags)
 {
 	struct irq_info *info = info_for_irq(irq);
@@ -193,6 +195,7 @@
 	info->u.pirq.pirq = pirq;
 	info->u.pirq.gsi = gsi;
 	info->u.pirq.vector = vector;
+	info->u.pirq.domid = domid;
 	info->u.pirq.flags = flags;
 }
 
@@ -655,7 +658,7 @@
 		goto out;
 	}
 
-	xen_irq_info_pirq_init(irq, 0, pirq, gsi, irq_op.vector,
+	xen_irq_info_pirq_init(irq, 0, pirq, gsi, irq_op.vector, DOMID_SELF,
 			       shareable ? PIRQ_SHAREABLE : 0);
 
 out:
@@ -680,7 +683,8 @@
 }
 
 int xen_bind_pirq_msi_to_irq(struct pci_dev *dev, struct msi_desc *msidesc,
-			     int pirq, int vector, const char *name)
+			     int pirq, int vector, const char *name,
+			     domid_t domid)
 {
 	int irq, ret;
 
@@ -693,7 +697,7 @@
 	irq_set_chip_and_handler_name(irq, &xen_pirq_chip, handle_level_irq,
 				      name);
 
-	xen_irq_info_pirq_init(irq, 0, pirq, 0, vector, 0);
+	xen_irq_info_pirq_init(irq, 0, pirq, 0, vector, domid, 0);
 	ret = irq_set_msi_desc(irq, msidesc);
 	if (ret < 0)
 		goto error_irq;
@@ -722,7 +726,7 @@
 
 	if (xen_initial_domain()) {
 		unmap_irq.pirq = info->u.pirq.pirq;
-		unmap_irq.domid = DOMID_SELF;
+		unmap_irq.domid = info->u.pirq.domid;
 		rc = HYPERVISOR_physdev_op(PHYSDEVOP_unmap_pirq, &unmap_irq);
 		if (rc) {
 			printk(KERN_WARNING "unmap irq failed %d\n", rc);