diff -ur xen-4.2.1.orig/xen/drivers/passthrough/vtd/intremap.c xen-4.2.1/xen/drivers/passthrough/vtd/intremap.c
--- xen/drivers/passthrough/vtd/intremap.c	2012-12-17 23:01:55.000000000 +0800
+++ xen/drivers/passthrough/vtd/intremap.c	2013-05-15 23:09:06.704546506 +0800
@@ -440,16 +440,17 @@
     type = pdev_type(seg, bus, devfn);
     switch ( type )
     {
+    case DEV_TYPE_PCIe_ENDPOINT:
     case DEV_TYPE_PCIe_BRIDGE:
     case DEV_TYPE_PCIe2PCI_BRIDGE:
-    case DEV_TYPE_LEGACY_PCI_BRIDGE:
-        break;
 
-    case DEV_TYPE_PCIe_ENDPOINT:
         set_ire_sid(ire, SVT_VERIFY_SID_SQ, SQ_ALL_16, PCI_BDF2(bus, devfn));
         break;
 
     case DEV_TYPE_PCI:
+    case DEV_TYPE_LEGACY_PCI_BRIDGE:
+    /* case DEV_TYPE_PCI2PCIe_BRIDGE: */
+
         ret = find_upstream_bridge(seg, &bus, &devfn, &secbus);
         if ( ret == 0 ) /* integrated PCI device */
         {
@@ -461,10 +462,15 @@
             if ( pdev_type(seg, bus, devfn) == DEV_TYPE_PCIe2PCI_BRIDGE )
                 set_ire_sid(ire, SVT_VERIFY_BUS, SQ_ALL_16,
                             (bus << 8) | pdev->bus);
-            else if ( pdev_type(seg, bus, devfn) == DEV_TYPE_LEGACY_PCI_BRIDGE )
+            else
                 set_ire_sid(ire, SVT_VERIFY_BUS, SQ_ALL_16,
                             PCI_BDF2(bus, devfn));
         }
+        else
+            dprintk(XENLOG_WARNING VTDPREFIX,
+                    "d%d: no upstream bridge for %04x:%02x:%02x.%u\n",
+                    pdev->domain->domain_id,
+                    seg, bus, PCI_SLOT(devfn), PCI_FUNC(devfn));
         break;
 
     default: