It's a simple problem. Yast makes a config looking like this:

disk = [ 'file:/var/lib/xen/images/dom1/hda,hda,w' ]
memory = 128
kernel = "/var/lib/xen/images/dom1/vmlinuz-2.6.13-8-xen"
ramdisk = "/var/lib/xen/images/dom1/inst-initrd"
name = "dom1"
dhcp = "dhcp"
vif = "[ 'mac=00:30:84:00:00:01' ]"
extra = ""
root = ""

which causes quiet a lot trouble like this:

Unexpected error: exceptions.ValueError

Please report to xen-devel@lists.xensource.com
Traceback (most recent call last):
  File "/usr/sbin/xm", line 10, in ?
    main.main(sys.argv)
  File "/usr/lib/python2.4/site-packages/xen/xm/main.py", line 707, in main
    rc = cmd(args)
  File "/usr/lib/python2.4/site-packages/xen/xm/main.py", line 176, in xm_create
    create.main(args)
  File "/usr/lib/python2.4/site-packages/xen/xm/create.py", line 822, in main
    preprocess(opts, opts.vals)
  File "/usr/lib/python2.4/site-packages/xen/xm/create.py", line 718, in preprocess
    preprocess_vifs(opts, vals)
  File "/usr/lib/python2.4/site-packages/xen/xm/create.py", line 593, in
preprocess_vifs
    (k, v) = b.strip().split('=', 1)
ValueError: need more than 1 value to unpack


The problem is the quotation mark around the mac address, this line should look
like the disk entry, just without the quotation mark.