Problem booting Fedora 8 guest on FC6 host

Hi,

I'm trying to get a Fedora 8 para-virtual guest to run on a FC6 host.

I had problems with the install because of the bugs in the 0.200 release
of virtinst. I fixed this by doing a source install of virtinst-0.300.

The F8 install completed succesfully, but when the guest boots I get
this msg:

<snip initial boot msgs>
md: Autodetecting RAID arrays.
md: autorun ...
md: ... autorun DONE.
VFS: Cannot open root device "vg_skeggles/lv_root" or unknown-block(0,0)
Please append a correct "root=" boot option
Kernel panic - not syncing: VFS: Unable to mount root fs on
unknown-block(0,0)

Has anyone got any ideas about how to fix this?

I am currently using kernel-xen-2.6.20-1.2952.fc6 and xen 3.0.3-9.fc6
(I've upgraded to kernel-xen-2.6.20-1.3002.fc6 and xen-3.0.3-13.fc6 but
not rebooted yet).

My xen config file (created automatically by virt-install) is as follows:

name = "skeggles"
uuid = "a8912edd-ea7c-f324-f1bb-fdbc0c1a4b65"
maxmem = 512
memory = 512
vcpus = 1
bootloader = "/usr/bin/pygrub"
on_poweroff = "destroy"
on_reboot = "restart"
on_crash = "restart"
sdl = 0
vnc = 0
vncunused = 0
disk = [ "phy:/dev/vg_guests/lv_skeggles,xvda,w" ]
vif = [ "mac=00:16:3e:4c:82:c7,bridge=xenbr0" ]


Thanks,

R.