I have a CentOS (6.8) box running as Dom0 that uses
xen-4.6.3-4.el6.x86_64.rpm kernel-3.18.44-20.el6.x86_64.rpm
and friends from the virt repo.
I can get a basic X environment (Vesa driver) when running in non-Xen mode but, when booting into the hypervisor, that fails.
I've tried one suggestion, adding a nopat to the kernel invocation, but that hasn't helpd although I'm sure the full suggestion, which I can no longer find, also mentioned an "mtrr" addition as well.
I'm also sure believe I even saw someone get pointed to some "aftermarket" xorg-x11 RPMs that claimed to work better with the Xen4CentOS environment than the standard ones.
My ability to search the interweb thing and find this info has clearly fallen to an all time low, so, does anyone on here have a better memory than I do, as regards that stuff ? (Assuming i didn't dream it!)