[libvirt] vhost-net configuration

Hi everyone, I'm trying to test out the virtio driver's "tx=bh" option, or iothread in libvirt. When I create a machine, I get the "unsupported" error message: # virsh create web101.xml error: Failed to create domain from web101.xml error: unsupported configuration: vhost-net is not supported with this QEMU binary My interface XML looks like this: <interface type='bridge'> <mac address='52:54:00:6f:51:43'/> <source bridge='vnet0'/> <model type='virtio'/> <driver name='vhost' txmode='iothread'/> <address type='pci' domain='0x0000' bus='0x00' slot='0x03' function='0x0'/> </interface> I've compiled libvirt (0.9.1) and QEMU (0.14.1) from source, but am still using my distro's kernel, 2.6.32-71.29.1.el6.x86_64. (Scientific Linux 6) Thanks, and please let me know if you need any more info! --Cal