How to launch QEMU from command line without libvirt with macvtap and vhost support
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=$(< /sys/class/net/testtap/address)
This sets up two different fd's. The first for macvtap and the second for vhost-net.
ip link del testbr
ip link del testvlan
ip link del testtap
ip link add name testbr type bridge
ip link add link testbr name testvlan type macvlan mode bridge
ip addr add 172.20.0.1/16 dev testvlan
ip link set dev testvlan up
ip link set dev testbr up
ip link add link testbr name testtap type macvtap mode bridge
ip link set testtap up
tapindex=$(< /sys/class/net/testtap/ifindex)
tapdev=/dev/tap"$tapindex"
echo "Tap Index :=" $tapindex
echo "Tap Dev :=" $tapdev
echo "Mac Address :="
cat /sys/class/net/testtap/address
../x86_64-softmmu/qemu-system-x86_64 -trace events=/tmp/events
-machine pc-lite,accel=kvm,kernel_irqchip,nvdimm -cpu host -m 256,maxmem=1G,slots=2 -smp 2 -no-user-config -nodefaults -rtc base=utc,driftfix=slew -global kvm-pit.lost_tick_policy=discard
-kernel ./vmlinux-4.9.34-63.1.container -append "reboot=k panic=1 rw tsc=reliable no_timer_check noreplace-smp root=/dev/pmem0p1
init=/usr/lib/systemd/systemd initcall_debug rootfstype=ext4 rootflags=dax,data=ordered dhcp rcupdate.rcu_expedited=1 clocksource=kvm-clock console=hvc0 single iommu=false quiet"
-device virtio-serial-pci,id=virtio-serial0 -chardev pty,id=charconsole0 -device virtconsole,chardev=charconsole0,id=console0 -nographic
-object memory-backend-file,id=mem0,share,mem-path=./clear-16160-containers.img,size=235929600 -device nvdimm,memdev=mem0,id=nv0 -no-reboot
-netdev tap,fd=3,id=hostnet0,vhost=on,vhostfd=4 3<>$"$tapdev" 4<>/dev/vhost-net -device virtio-net-pci,netdev=hostnet0,id=net0,mac=$(< /sys/class/net/testtap/address)