Libvirt 0.9.11 has Support for Open vSwitch

Libvirt 0.9.11 has Support for Open vSwitch

Libvirt release 0.9.11 has added support for Open vSwitch so it is no longer required to use bridge compatibility mode! Fedora 17 has 0.9.11 included.

If you have brcompat enabled disable it.

Configuration basically consists of adding the following line to a interface setup in bridge mode with the bridge being a OVS bridge.

<virtualport type='openvswitch'/>

Here are a few links to point you in the right direction.

Configuring a domain's network interface to use Open vSwitch
http://openvswitch.org/cgi-bin/gitweb.cgi?p=openvswitch;a=blob_plain;f=INSTALL.Libvirt;hb=HEAD

Additional information on Open vSwitch Hypervisor integration. 
 http://openvswitch.org/cgi-bin/gitweb.cgi?p=openvswitch;a=blob_plain;f=IntegrationGuide;hb=HEAD

If you have a version of libvirt older than 0.9.11 you will still need to use bridge compatibility mode as described in the previous posthttp://binarybitme.blogspot.com/2011/09/using-open-vswitch-with-libvirt-and.html