With ipxe-roms-qemu-20160127-1.git6366fa7a.el7.noarch installed, it sets the default virtio NIC in qemu to include efi-virtio.rom which isn't provided. This prevents any new VMs from being created through virt-manager. Attempting to remove ipxe-roms-qemu in an attempt to fix this takes the entire virtualization group with it. One caveat to this whole setup, which may be 100% my fault: this was on a Fedora 23 workstation with the rdo-release.repo from CentOS/RDO enabled for some OpenStack testing. 'journalctl --since "19:48:00" --until "19:51:00" -u libvirtd -ocat -f': (interface_definition):11: Extra content at the end of the document </interface><interface type="ethernet" name=""> ------------^ Unable to read from monitor: Connection reset by peer internal error: early end of file from monitor: possible problem: 2016-05-25T00:50:04.733910Z qemu-system-x86_64: -device virtio-net-pci,netdev=hostnet0,id=net0,mac=52:54:00:3a:ca:30,bus=pci.0,addr=0x3: failed to find romfile "efi-virtio.rom" failed to connect to monitor socket: No such process internal error: process exited while connecting to monitor: 2016-05-25T00:50:32.885501Z qemu-system-x86_64: -device virtio-net-pci,netdev=hostnet0,id=net0,mac=52:54:00:3a:ca:30,bus=pci.0,addr=0x3: failed to find romfile "efi-virtio.rom"
This bug is against a Version which has reached End of Life. If it's still present in supported release (http://releases.openstack.org), please update Version and reopen.