I haven't fired up my debian testing vm in a while but I did the other day and upgraded it and now whenever X starts up, the keyboard dies. Can't even switch back to a tty. Booting in multi-user.target works fine, just not graphical.target. I thought I'd try to reinstall so I downloaded the latest testing netinst iso and no matter which item I choose from the boot menu, the domU just reboots.
I'm not sure how to report this as a proper bug report.