As of September 2010, vhost is not included in any released tarballs, so you need the git version. VhostNet provides better latency (10% less than e1000 on my system) and greater throughput (8x the normal virtio, around 7~8 Gigabits/sec here) for network. Obtaining the code You need the at least qemu-kvm-0.13.0 (http://sourceforge.net/projects/kvm/files/qemu-kvm/) kernel requirements On the host y