Interestingly, after i lock the qemu console up with the xdo script,
the screen is always locked in ctrl-alt-2, that is, the monitor, not the vm display,
hitting ctrl-alt-1 never returns it to the vm display,
but if i continue the xdo script running, it sometimes does return to the vm display, where you can see memtest continuing to run.
So it appears that what is locking up is the display of the monitor.
Interestingly, after i lock the qemu console up with the xdo script,
the screen is always locked in ctrl-alt-2, that is, the monitor, not the vm display,
hitting ctrl-alt-1 never returns it to the vm display,
but if i continue the xdo script running, it sometimes does return to the vm display, where you can see memtest continuing to run.
So it appears that what is locking up is the display of the monitor.