I've tested the most recent kernel from Michael Young http://koji.fedoraproject.org/koji/taskinfo?taskID=2598434 kernel vmlinuz-2.6.37-0.1.rc1.git8.xendom0.fc14.x86_64(rc1.git8 + xen-next.patch) as Dom0 kernel under Xen 4.0.1 on top of F14. Attempt to work with NFS remote folder results kernel crash again - unable to handle paging request and stack trace.
Kernel works OK only as vanilla.
Boris. P.S. Same issue is in place for PV DomU running kernel vmlinuz-2.6.37-0.1.rc1.git8.xendom0.fc14.x86_64