[Cialug] Xen hupervisor boot configuration missing

[L. V. Lammert]

Updates a system recently, and there are some VMs on it that are not being
used but need to get updated. I was very surprised when I could not
connect to libvirtd; after some testing, it appears the hypervisor is not
even running, and that option on the boot menu seems to have disappeard.

The last update apparently removed the boot loader config, .. but the
package manager thinks Xen and Xen-tools are installed, so cannot
reinstall.

How would one rebuild the boot config itself?

	TIA!