[Fedora-xen] Re: Heads-up: Requiring PAE for running Xen

[Jeremy Katz]

On Sat, 2006-05-20 at 17:40 +0200, Thorsten Leemhuis wrote:
> Am Samstag, den 20.05.2006, 16:14 +0200 schrieb Axel Thimm: 
> > On Wed, May 17, 2006 at 02:07:59PM -0400, Jeremy Katz wrote:
> > > As we move forward with Xen enablement, there's a desire for
> > > being able to access more than 4 gigs of RAM on 32-bit Xen hosts.  The
> > > options for handling this are
> > [...] 
> > > 2) Switch the 32-bit xen kernels to require PAE.  For most "current"
> > > non-laptop hardware, this is a non-issue.  It does mean that xen won't
> > > work a lot of earlier PentiumM laptops
> > [...]
> > > Given these, we're looking at going with #2 and thus only having Xen
> > > work on PAE-capable hardware in the development tree.  And we're
> > > planning to try to execute this switchover the beginning of next week.
> > > Note that this will not affect bare metal installs at all.
> > [...] 
> > So maybe rawhide should continue with both PAE and non-PAE kernels and
> > decide on dropping the non-PAE when a release is about to be cut?
> > Otherwise you will keep out a large amount of (admittedly casual)
> > testers.
> 
> Well, I was always against kernel's in Fedora Extras (and I still am,
> [mostly]). But having a Xen non-PAE kernel in Extras sounds like the
> proper solution for the above problem. But having kernels in Extras
> would only be okay for me if
> - they are build with the same spec-file as the other kernels
> - they are build on the same build system in the same step as the other
> kernels
> - they are moved to the proper Extras repo in the same moment as the
> other kernels are pushed out

This involves huge fundamental changes to the build infrastructure that
I'm really not sure are worth doing

> There are some technical problems that probably would need to be solved
> before the above could be realized, but that should be possible if we
> really want to.

The other problem is the kernel binaries *have* to be with the
installer, too -- otherwise, you can't install the guest as everything
(HV + dom0 kernel + domU kernel) has to either be PAE or not.  Mixing
and matching can't happen :(

Jeremy