Markus Schönhaber, Mon, 3 Dec 2018 13:58:31 +0100:
M A Young, Mon, 3 Dec 2018 12:33:40 +0000 (GMT):
It looks like the "Linux 4.19.5 fails to boot as Xen dom0" issue being discussed on the xen-devel list, eg. see https://lists.xenproject.org/archives/html/xen-devel/2018-11/msg03557.html Basically there is an issue with the 4.19.5 kernel that upset Xen.
Thanks for the pointer! Guess, I'll try to rebuild the kernel with the patches posted there to see if that not only fixes booting as Dom0 but also as DomU.
Indeed, my DomU boots fine with an upstream 4.19.5 kernel with those patches applied.