I just tested this: GRUB_TERMINAL_INPUT="console serial" GRUB_TERMINAL_OUTPUT="console serial" GRUB_SERIAL_COMMAND="serial --speed=115200 --unit=0 --word=8 --parity=no --stop=1"
And it worked fine with grub actually showing up with 'virsh console' and no problems booting under openstack either. This would likely be the preferred solution.
