Comment 11 for bug 1817943

Just removing the assert (somewhat unsurprisingly) isn't enough to make it work.

(Additional apparmor rules)
  /proc/modules r,
  /proc/driver/nvidia/params r,
  /etc/glvnd/egl_vendor.d/{,*} r,
  /usr/share/egl/egl_external_platform.d/ r,
  /usr/share/egl/egl_external_platform.d/** r,
  /sys/devices/** r,
  /sys/devices/ r,
  /dev/nvidiactl rw,

The VM now starts, but displays nothing, and you can get virt-manager to crash with possibly related line (If you have viewer open when you start the VM):
Mar 01 00:14:42 desktop libvirtd[1475]: End of file while reading data: Input/output error