--- libvirt-1.2.8.orig/src/qemu/qemu_command.c
+++ libvirt-1.2.8/src/qemu/qemu_command.c
@@ -1795,7 +1795,8 @@ qemuDomainMachineIsI440FX(virDomainDefPt
             STRPREFIX(def->os.machine, "pc-0.") ||
             STRPREFIX(def->os.machine, "pc-1.") ||
             STRPREFIX(def->os.machine, "pc-i440") ||
-            STRPREFIX(def->os.machine, "rhel"));
+            STRPREFIX(def->os.machine, "rhel") ||
+            STREQ(def->os.machine, "ubuntu"));
 }
 
 
@@ -1995,7 +1996,8 @@ qemuAssignDevicePCISlots(virDomainDefPtr
         STRPREFIX(def->os.machine, "pc-1.") ||
         STRPREFIX(def->os.machine, "pc-i440") ||
         STREQ(def->os.machine, "pc") ||
-        STRPREFIX(def->os.machine, "rhel")) &&
+        STRPREFIX(def->os.machine, "rhel") ||
+        STREQ(def->os.machine, "ubuntu")) &&
         qemuValidateDevicePCISlotsPIIX3(def, qemuCaps, addrs) < 0) {
         goto error;
     }
--- libvirt-1.2.8.orig/src/qemu/qemu_domain.c
+++ libvirt-1.2.8/src/qemu/qemu_domain.c
@@ -739,7 +739,8 @@ qemuDomainDefPostParse(virDomainDefPtr d
             !STRPREFIX(def->os.machine, "pc-1.") &&
             !STRPREFIX(def->os.machine, "pc-i440") &&
             !STREQ(def->os.machine, "pc") &&
-            !STRPREFIX(def->os.machine, "rhel"))
+            !STRPREFIX(def->os.machine, "rhel") &&
+            !STREQ(def->os.machine, "ubuntu"))
             break;
         addPCIRoot = true;
         break;