This problem still exists for me, I still have to downgrade to run kernel linux-image-2.6.32-5-xen-amd64_2.6.32-18_amd64.deb (from july 2010)
for it to work. The discussion not leading to a solution can be found here: http://lists.xensource.com/archives/html/xen-users/2010-09/msg00488.html In other words, most recent kernel in Debian stable does not work as a Dom0 kernel for me! I have to go "in production" by the end of next week and it would feel much better to use a more recent Dom0 kernel :) /Erik