[Pkg-xen-devel] Xen status in lenny?

[Pasi Kärkkäinen]

On Tue, Jul 15, 2008 at 01:08:23PM +0200, Lucas Nussbaum wrote:
> On 12/07/08 at 19:39 -0700, Steve Langasek wrote:
> > On Sun, Jul 13, 2008 at 12:10:28AM +0200, Lucas Nussbaum wrote:
> > > We (Debian) should make a clear statement that users of Debian as dom0
> > > will have at least one supported configuration at any time during the
> > > lenny lifetime.
> > 
> > What I don't see you saying is that *you* are volunteering to step up and
> > help provide security support for this kernel.  So it's "we" when we're
> > making a statement, but it's still "they" who would have to provide the
> > actual support, AFAICS.
> 
> How/if we will support Xen in lenny is more a policy decision than a
> technical decision, even if it has important technical aspects.
> 
> Even if it's not optimal, I agree with do-ocracy for technical
> decisions. However, using it for everything is dangerous. Instead, I
> prefer to:
> 1/ understand the situation
> 2/ determine the possible solutions
> 3/ determine the best solutions, given external constraints (inc.
>    manpower)
> 4/ try to find someone to do the work
> 
> Throwing "you are not going to do the work anyway, so you are
> irrelevant" at everybody is not helpful at all, and just adds noise to
> the discussion, because we are still between stages 2 and 3 here.

The situation is pretty much like this:

- Upstream vendor (Xensource) only develops 2.6.18 Xen dom0/domU kernel atm.

- paravirt_ops (pv_ops) Xen support in vanilla (v2.6.24+) Linux kernels is currently
  domU only. Also it's 32bit PAE only, no 64bit yet. Other features are
  missing too (compared to xensource 2.6.18 xen kernel).

- Xen kernel features from 2.6.18 are being ported and added slowly to 2.6.2x
  pv_ops kernels but it takes time and effort to get them ported and accepted 
  upstream (by linus). Currently Jeremy Fitzhardinge (from Xensource) is doing 
  this work. I think currently he's working on getting 64bit domU support ready/integrated.

- Redhat/Fedora has done some pv_ops xen dom0 support work, but it's not
  ready yet and it hasn't had much progress lately.. unfortunately.

- 2.6.22 and 2.6.24 (non pv_ops) kernels with forward ported patches from 2.6.18 
  are a real pain for kernel maintainers.. 

- Fedora decided to drop dom0 xen kernel for Fedora 9. Fedora 9 only ships
  with xen pv_ops domU kernel. They're planning to add dom0 support back for 
  Fedora 10 if/when (pv_ops) dom0 support is included in the upstream 
  vanilla (linus) kernel. 

Some links:

http://wiki.xensource.com/xenwiki/XenParavirtOps
http://fedoraproject.org/wiki/Features/XenPvopsDom0

-- Pasi