[fedora-virt] old xen Windows XP hvm to kvm avoiding activation problems?

[Tom Horsley <tom horsley att net>]

Are there any hints out there for how I can try to convert a
Windows XP hvm running on a fairly old version of xen to
a nice new fedora 12 KVM and (the tricky part) avoid XP
deciding it needs to be reactivated?

What things should I look at in windows to decide how to
tweak the KVM machine xml so it will be as close as possible to
the same virtual hardware windows had before?