From grub.conf:
title Fedora Core Xen (2.6.12-1.1454_FC4xen0)
root (hd0,0)
kernel /boot/xen.gz
module /boot/vmlinuz-2.6.12-1.1454_FC4xen0 ro root=LABEL=/ rhgb quiet
module /boot/initrd-2.6.12-1.1454_FC4xen0.img
Xen runs in ring 0 (approx 32MB)
Linux runs in ring 2/3
