NetKVM with no host-to-guest packet loss (finally)

gistfile1.txt

<interface type="bridge">
  <mac address="52:54:00:52:cb:4c"/>
  <source bridge="br0"/>
  <model type="virtio"/>
  <driver name="vhost" txmode="iothread" ioeventfd="on" event_idx="on" queues="4" rx_queue_size="256" tx_queue_size="256">
    <host csum="on" gso="on" tso4="on" tso6="on" ecn="on" ufo="on" mrg_rxbuf="on"/>
    <guest csum="on" tso4="on" tso6="on" ecn="on" ufo="on"/>
  </driver>
  <coalesce>
    <rx>
      <frames max="12"/>
    </rx>
  </coalesce>
  <address type="pci" domain="0x0000" bus="0x01" slot="0x00" function="0x0"/>
</interface>