Index: libvirt-1.2.16/src/qemu/qemu_capabilities.c
===================================================================
--- libvirt-1.2.16.orig/src/qemu/qemu_capabilities.c	2015-11-04 22:42:57.909801821 +0000
+++ libvirt-1.2.16/src/qemu/qemu_capabilities.c	2015-11-04 23:09:17.099801821 +0000
@@ -3288,6 +3288,9 @@
     /* Since 2.4.50 ARM virt machine supports gic-version option */
     if (qemuCaps->version >= 2004050)
         virQEMUCapsSet(qemuCaps, QEMU_CAPS_MACH_VIRT_GIC_VERSION);
+    /* Ubuntu backported it to 2.4.0 */
+    else if (qemuCaps->version >= 2004000 && qemuCaps->Package && strstr(qemuCaps->package, "ubuntu"))
+        virQEMUCapsSet(qemuCaps, QEMU_CAPS_MACH_VIRT_GIC_VERSION);
 
     if (virQEMUCapsProbeQMPCommands(qemuCaps, mon) < 0)
         goto cleanup;