Add virtio-gpu & virgl, if supported by guest OS
Submitted by Marc-Andre Lureau
This patch is untested.
Assuming your host has all the latest qemu/libvirt/libvirt-glib/osinfo/spice-gtk etc, then this patch should be enough to setup a VM with virgl support.
Most of the required bits are already merged upstream and pending release, the libvirt/libvirt-glib/osinfo are not yet upstream.