Hi!
After installing kernel-xen0 from RawHide, the following lines were added to my /boot/grub/menu.lst:
title Fedora Core (2.6.10-1.1074_FC4xen0) root (hdX,X) kernel /vmlinuz-2.6.10-1.1074_FC4xen0 ro root=/dev/XXX initrd /initrd-2.6.10-1.1074_FC4xen0.img
However, this is incorrect, as vmlinuz-2.6.10-1.1074-FC4xen0 cannot be booted by GRUB directly (must be ran under the control of the XEN hypervisor). Instead, GRUB *must* boot /boot/xen.gz which is the XEN hypervisor kernel. Thus, /boot/grub/menu.lst should look like this:
title Fedora Core (2.6.10-1.1074_FC4xen0) root (hdX,X) kernel /xen.gz dom0_mem=400000 noreboot module /vmlinuz-2.6.10-1.1074_FC4xen0 ro root=/dev/XXX module /initrd-2.6.10-1.1074_FC4xen0.img
Note how now xen.gz is the kernel, and take note of the "dom0_mem" kernel parameter which is needed for XEN to allocate physical memory for XEN's domain 0, Omitting the "dom0_mem" parameter makes XEN allocate too little memory for the domain 0 kernel which, as result, will crash with an Out of Memory error.
"dom0_mem=400000" could default to "dom0_mem=130000" instead. This shouldn't be much of a problem since if we try to allocate more memory than the maximum available RAM, XEN hypervisor will complain. However, omitting "dom0_mem" will make the Linux kernel crash and reboot, which is much worse.
Should I fill in a bug report for this? Thanks.