I change always manually the serial/graphical. When running cmake
you can define variable QEMU_ACCEL that will be used as accelerator.
Also ninja has the following targets for running qemu
1. qemu: Run graphical qemu environment
2. qemu-nographic: Run qemu without graphical screen. You should
select 'serial only' from grub menu.
3. qemu-debug: Run qemu without accelerator and interrupt
debugger.
Bananymous