Comment # 9 on bug 1003999 from Ruediger Oertel

> how did that /dev/dm-N work for KVM guests? 
any block device works, this is just a device mapper device.
for qemu/kvm we are using virtio for basically everything, even console.
the classic worker setup had logical volumes for both kvm and xen.
(current workers just use files in a tmpfs instead, but you need enough
ram to do this ...)

anyway, fixed
github.com:openSUSE/obs-build.git commit
d65f0f936ffc4632f49ca2906cbf554f0474938b
has the changes.

(plus the missing xenblk (xen-blkfront) in the initrd used, which was the first
problem encountered in the bug.)