Hi Dan, On a system with stock rawhide kernel (not the xen one), I get two new test failures because virCapabilitiesSupportsGuestOSType(caps, "xen") returns 0. $ ./qemuxml2xmltest 1) QEMU XML-2-XML minimal ... OK 2) QEMU XML-2-XML boot-cdrom ... OK 3) QEMU XML-2-XML boot-network ... OK 4) QEMU XML-2-XML boot-floppy ... OK 5) QEMU XML-2-XML bootloader ... libvir: QEMU error : unknown OS type xen FAILED 6) QEMU XML-2-XML clock-utc ... OK 7) QEMU XML-2-XML clock-localtime ... OK 8) QEMU XML-2-XML disk-cdrom ... OK 9) QEMU XML-2-XML disk-floppy ... OK 10) QEMU XML-2-XML disk-many ... OK 11) QEMU XML-2-XML disk-xenvbd ... OK 12) QEMU XML-2-XML graphics-vnc ... OK 13) QEMU XML-2-XML graphics-sdl ... OK 14) QEMU XML-2-XML input-usbmouse ... OK 15) QEMU XML-2-XML input-usbtablet ... OK 16) QEMU XML-2-XML input-xen ... libvir: QEMU error : unknown OS type xen FAILED 17) QEMU XML-2-XML misc-acpi ... OK 18) QEMU XML-2-XML misc-no-reboot ... OK 19) QEMU XML-2-XML net-user ... OK 20) QEMU XML-2-XML net-virtio ... OK 21) QEMU XML-2-XML serial-vc ... OK 22) QEMU XML-2-XML serial-pty ... OK 23) QEMU XML-2-XML serial-dev ... OK 24) QEMU XML-2-XML serial-file ... OK 25) QEMU XML-2-XML serial-unix ... OK 26) QEMU XML-2-XML serial-tcp ... OK 27) QEMU XML-2-XML serial-udp ... OK 28) QEMU XML-2-XML serial-tcp-telnet ... OK 29) QEMU XML-2-XML serial-many ... OK 30) QEMU XML-2-XML parallel-tcp ... OK 31) QEMU XML-2-XML console-compat ... OK [Exit 1] qemuxml2argvtest fails the same way.