Xen Dom0, are we making progress?

[Nikolas Britton]

On 3/13/07, Kip Macy <kip.macy at gmail.com> wrote:
> > I know you were working on Xen support in FreeBSD, but web about it
> > (http://www.fsmware.com/xenofreebsd/7.0/STATUS) has one year old info
> > (support planned in FreeBSD 6.1). So is there any progress, or Xen will
> > not be in any near future release?
>
> Basically Xen did not mature in the fashion that I anticipated. As far
> as I can tell it is really only good for server consolidation for
> large Linux distro vendors. You need to have what amounts to a private
> branch. The xen developers don't appear to understand the importance
> of interface versioning. They broke ABI compatibility going from 3.0.2
> -> 3.0.3 (trivial to fix, but that is not the point). When last I
> worked on it, they had one branch that was in constant flux and
> another branch that only received minor bug fixes and was 18 months
> behind from a functionality standpoint (think 5.x / 4.x). There are
> numerous other logging / supportability issues that I think are only
> addressed by the major distros. As it stood 6 months ago, unless you
> understood the internals of various bits of the code, there was no way
> of diagnosing failures due to a misconfiguration.
>
> This is not to say that it isn't cool technology, but rather that
> isn't going to be useful for the things I wanted to use it for so my
> time is being directed elsewhere. If I ever have a need for EC2 I may
> look at it again.
>
> One of the guys who ported FreeBSD to the xbox has expressed interest
> - so something may yet come of it.
>
> I'm happy to provide technical support to an individual who is largely
> self-sustaining in working on the code.
>

What about implementing something like DragonFly BSD virtual kernels?
Matthew Dillon talks about it in is bsdtalk interview:
http://cisx1.uma.maine.edu/~wbackman/bsdtalk/bsdtalk098.mp3

I suppose it's sorta like linux compat / windows on windows /
coLinux... Towards the end of the interview he talk about it being
extremely easy to implement:
1. signal mailboxes.
2. memory map / virtual page table support.
3. vm space management.