Is there a setting to allow/disable spoof checking and trust on VF from SR-IOV device? 
Lookin at https://www.libvirt.org/formatdomain.html#elementsDriverBackendOptions can this be done through the driver element?
<driver name='vhost' txmode='iothread' ioeventfd='on' event_idx='off' queues='5' rx_queue_size='256' tx_queue_size='256'>
      <host csum='off' gso='off' tso4='off' tso6='off' ecn='off' ufo='off' mrg_rxbuf='off'/>
      <guest csum='off' tso4='off' tso6='off' ecn='off' ufo='off'/> </driver>
At the moment i have to manually run: 
ip link set $_dev vf $vf spoofchk off
ip link set $_dev vf $vf trust on

Is it possible to set this values from the xml file on a per interface basis?