Comment from theinvisiblethings blog: "I doubt this will work from a xen domU or dom0 context because 1) AFAIK you don't have access to MTRR registers from there 2) their kernels are running in ring1 not ring0." Maybe openvz/vserver virtualization restrict access to MTRR somehow too... why you so sure?

As many have pointed out, there's no real point to "exploiting" a machine that you already have full (root) access to - with one exception: virtual servers.

The whole 'danger' of this exploit is that it enables a virtual server's "privileged" "root" user to gain hypervisor access, which is equivalent to taking over the entire physical machine and any/all other virtual servers hosted on said machine.

If you don't run a virtual server farm, this exploit means absolutely nothing to you. If you do, it's a very easy, scary way whereby any of your "clients" can take over your physical machines and access all of the other virtual servers hosted on the same piece of hardware.

I think you are right, because I checked again, and only 10 or so domains currently are owned by the State of Kentucky. Yesterday, the number was much higher - over half - and it wasn't a matter of registrar compliance (I don't think the individual registrars had a say in the matter), ICANN was the one who handed control of the domains to the State.