> So : I'm thinking that the kernel isn't the problem and that it might
> come from the config file and more precisely the disks. I'm using ext2
> formated diskfiles. I've extracted the base and etc i386 sets in the
> root diskfile, also tried with xen-i386 sets from xen website.
>
>
> question : any idea of what's the problem ? is it because I'm using
> diskfiles and not partitions ? or is it a kernel problem ?

Yes, you're missing a NetBSD disklabel on your disks/images.  It should work 
if you specify the raw partition as the root device, i.e.
extra = "bootdev=xbd0d"

Btw, the kernel config file you used doesn't seem to have the wd/sd 
identities for the block devices enabled?  Your exported disks would 
otherwise appear as sd0 and sd1 and not xbd0 and xbd1 and the bootdev 
argument would be sd0d...

    christian

> xbd0 at hypervisor0: Xen Virtual Block Device 2048 MB
> xbd1 at hypervisor0: Xen Virtual Block Device 256 MB
> boot device: xbd0
> root on xbd0a dumps on xbd0b
> mountroot: trying nfs...
> mountroot: trying ext2fs...
> root file system type: ext2fs
> warning: no /dev/console
> init: copying out path `/sbin/init' 11