>> which software do you mean here? xen 2, xen 3, plan 9 on xen[23]?
>
> All of it :-)
>
> My original intent was if any bit required to compile xenU kernel has
> changed enough to break compilation
The guest/host OS interface changed sufficiently between xen2 and xen3
that the 9xen network and block device drivers needed to be rewritten
from scratch.
The Plan 9 guest kernel needs to be compiled using the xen/public C header
files from the xen host version you want to run on. I have tested
it with xen3.0.2 (the current "stable" release), which is the only
xen3 version I have been able to build and run on any of my machines.
In theory a guest kernel built for xen3.0.n is supposed to work with
{xen3.0.m: m >= n}, but I wouldn't bet on it.
Above the kernel level, of course, everything does "just work" - in
fact I switch back and forth between native Plan 9 and 9xen using
the same fossil root file system.
