[Fedora-xen] Plans for paravirt_ops kernel-xen

[Mark McLoughlin]

Hi,
        Fedora's Xen hackers have been working hard towards switching
our kernel-xen package from a forward-ported Xensource kernel tree to a
state-of-the-art upstream, paravirt_ops based, kernel in Fedora 9 as
described here:

  http://fedoraproject.org/wiki/Features/XenPvops
  http://www.redhat.com/archives/fedora-xen/2007-November/msg00106.html

        Some great progress has been made, and tomorrow's rawhide will
have a kernel-xen update with:

  + A very recent 2.6.25-rc4 base

  + Xen paravirt_ops DomU from upstream

  + x86_64 Xen paravirt_ops DomU support

  + Paravirt framebuffer

        However, although the Dom0 paravirt_ops work is well advanced at
this point, we still don't have backend drivers or x86_64 Dom0 working.

        With the feature freeze looming next week, we have make the
difficult decision to focus the Fedora 9 efforts on DomU and postpone
the inclusion of paravirt_ops Dom0 support.

        The alternative course of action was to keep shipping the
2.6.21.7 based kernel-xen in Fedora 9, but we have ruled this out as a
supportable option. This kernel is almost a year old now and we cannot
expect Fedora hackers to keep the distribution working on such an old
kernel. Examples of the kind of issues we see cropping up are:

  1) Broken installs due to old squashfs:

       https://bugzilla.redhat.com/431109

  2) Broken SELinux due to old SELinux:

       https://bugzilla.redhat.com/436173

  3) Broken networking due to old netlink:

       https://bugzilla.redhat.com/431179

        We feel that making significant investment across the
distribution to keep this old kernel working for the sake of Dom0
support would be wasting effort on a dead codebase.

        Work will continue apace on the Dom0 paravirt_ops effort for
Fedora 10 and we hope to introduce the first build to rawhide soon after
Fedora 9 been branched. This first build should include backend drivers
and x86_64 support. If all goes well with the Dom0 support in Fedora 10
rawhide, we may well pull it into Fedora 9 as a post-GA update.

        So, in summary:

  1) Try out the F9 rawhide/beta paravirt_ops kernel-xen in your DomUs

  2) Keep your Dom0 on Fedora 8 for now

  3) If you want to help out with Dom0 paravirt_ops testing, then be
     ready to jump onto Fedora 10 rawhide

Thanks,
Mark.