This series implements Virtio spec update from Aaron Conole which
defines a way for the host to expose its max MTU to the guest.
This third version re-desings how MTU value is provided to QEMU.
Now, host_mtu parameter is added to provide QEMU with the MTU value,
and the backend, if supported, gets notified of the MTU value when the
MTU feature neogotiation succeeds.
Only user backend currently supports MTU notification. A new protocol
feature has been implemented for sending MTU value to the backend.
Aaron, Kevin, Flavio, do you confirm this works for OVS if DPDK vhost lib
adds needed API to get the MTU value?
For kernel backend, it is expected the management tool also configures
the tap/macvtap interface with same MTU value.
Daniel, I would be interrested about your feedback on this implementation
from management tool point of view.