Just a note to self. In the case of a serial console never getting around to the login prompt on a Xen DomU, even though it still displays all of the normal console boot messages, just change /etc/inittab as follows:

1:2345:respawn:/sbin/mingetty tty1

1:2345:respawn:/sbin/mingetty --noclear console

Also note: Why do we still call these things tty(s)? That is SOOO 70s!