[Xen-users] Problems converting FC8 HVM guest to PV

[Evan Lavelle <sa212+xen@xxxxxxxxxxx>]

I'm running a Fedora 8 Dom0, x86_64, with a Fedora 8 DomU, HVM, i386. 
I'd like to convert the (working) DomU to PV, but I've been banging my 
head against a brick wall for the last few hours. Can anyone point me in 
the right direction?
Plan A was to use pygrub, and to make a new DomU ramdisk with the 
xenblock module. I ran mkinitrd with --preload=xenblock, and set up a 
new grub entry on the DomU:
title Fedora (2.6.21-2952.fc8xen.xenblk)
 root (hd0,0)
 kernel /xen.gz-2.6.21-2952.fc8
 module /vmlinuz-2.6.21-2952.fc8xen ro root=LABEL=/ rhgb quiet
 module /initrd-2.6.21-2952.fc8xen.xenblk.img

The config file on the Dom0 was:

name   = "fc8-32-001"
memory = 1024
vcpus  = 1
vif  = [ 'mac=00:0f:b5:ae:4f:2a, bridge=xenbr0' ]
disk = [ 'phy:/dev/VG_Guests/FC8-32-001,hda,w' ,
         'file:/tmp/FC8-32.ISO,hdc:cdrom,r'];
bootloader="/usr/bin/pygrub"
boot = "cd"
sdl  = 1
vnc  = 0

When I created the domU, pygrub correctly gave me the boot menu from the 
DomU, but it wouldn't boot the entry above; it complained that it wasn't 
a valid kernel ("not a Xen-ELF image", and it wasn't a xen_guest). 
However, it *is* a valid (gzipped) Xen kernel (I know because readelf 
reports a __xen_guest entry, and if I use it as the HVM DomU kernel then 
uname reports it as a Xen kernel). So, I figured that pygrub was broken, 
and moved on to plan B.
Plan B was to move the 32-bit guest kernel and ramdisk to the Dom0, and 
modify the config file. I've tried lots of different variations on the 
config file, and I've currently got:
name   = "fc8-32-002"
memory = 1024
vcpus  = 1
vif  = [ 'mac=00:0f:b5:ae:4f:2a, bridge=xenbr0' ]
disk = [ 'phy:/dev/VG_Guests/FC8-32-001,hda,w' ];
#bootloader="/usr/bin/pygrub"
kernel  = "/boot/fc8-32/vmlinuz-2.6.21-2952.fc8xen"
ramdisk = "/boot/fc8-32/initrd-2.6.21-2952.fc8xen.img"
root    = "/dev/hda ro"
sdl     = 1
vnc     = 0

This doesn't work, and none of the variations worked. I copied the 
32-bit DomU Xenified kernel into the Dom0 path in the 'kernel' line. 
I've tried the config with and without the ramdisk line, and with the 
original 32-bit guest initrd, as well as my new xenblock version. I've 
tried variations on the 'hda' as well, and on the root line. I get 
several different error messages.
Any ideas? I suspect that I'm missing something obvious.

Thanks -

Evan

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