I am using Xen-4.4.0, libvirt-1.2.9 My ubuntu.cfg is: ubuntu10.cfg bootloader = "/usr/local/lib/xen/boot/hvmloader" builder="hvm" memory = 512 name = "ubuntu" vif = [ "type=ioemu,bridge=ovsbr0", "type=ioemu,bridge=ovsbr0","type=ioemu,bridge=ovsbr0","type=ioemu,bridge=ovsbr0",,"type=ioemu,bridge=ovsbr0"] device_model_version = "qemu-xen-traditional" If I didnot add " device_model_version = "qemu-xen-traditional" " to ubuntu.cfg, I only can add four NICs to VM. If I add five or more,, I got these errors: libxl: error: libxl_dm.c:1371:device_model_spawn_outcome: domain 12 device model: spawn failed (rc=-3) libxl: error: libxl_create.c:1186:domcreate_devmodel_started: device model did not start: -3 libxl: error: libxl_dm.c:1475:kill_device_model: Device Model already exited If I add " device_model_version = "qemu-xen-traditional" " to ubuntu.cfg, I can apply 8 NICs to VM. But, I want to create domU by virsh(libvirt), so How convert " device_model_version = "qemu-xen-traditional"" to xml file used by virsh? and How many NIC can a VM have? what leads to this limit？ -- Best Regards, yandong