This sets up a host local bridge with a macvlan interface for VM to host communication. The macvtap is setup with vhost support.
The command line options to note are
-netdev tap,fd=3,id=hostnet0,vhost=on,vhostfd=4 3<>$"$tapdev" 4<>/dev/vhost-net -device virtio-net-pci,netdev=hostnet0,id=net0,mac=$(< /sys/class/net/testtap/address)
This sets up two different fd's. The first for macvtap and the second for vhost-net.