Bug#500336: patch for grub detection

[Raphael Hertzog]

On Wed, 29 Oct 2008, Ian Campbell wrote:
> > > > So the problem would bite people upgrading grub but not the kernel.
> > > 
> > > Someone who installs 2.6.26-1-xen-amd64 in a Lenny domU with the Lenny
> > > version of grub would end up with a menu.lst which did not contain this
> > > kernel, which would be incorrect.
> > 
> > But this is only a problem for pygrub users and it looks like pygrub is
> > not even packaged for Debian. 
> 
> It's just part of Xen:
> 
> $ dpkg -S /usr/lib/xen-3.2-1/bin/pygrub 
> xen-utils-3.2-1: /usr/lib/xen-3.2-1/bin/pygrub

Hu, okay. I have been using Xen on multiple (etch) machines and never used
that. I always boot a kernel stored on the dom0.

> > http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=479478 ?
> 
> Yes something like that.
> 
> I previously had concerns because /proc/xen doesn't exist on pv ops
> kernels, but since we would not go down this path on a pv ops kernel
> this doesn't even make sense to me anymore, I'm not sure what I was
> thinking... Perhaps I was considering the future existence of pvops
> domain 0 kernels but since they don't yet exist and probably will
> have /proc/xen lets not worry.

I have troubles following your reasoning here. Are you saying that
the test on /proc/xen/capabilities shown above is enough and should be
reinstated for the sake of deciding if we're on a domU ?

Can you provide a patch for this that would also include Thomas's initial
patch ?

> If a user manually installs the non-paravirt -xen-686 kernel in a domU
> (which is not unlikely, even if I think its unnecessary...):

Well, I only have the linux-modules-*-xen-686 part in all my domU and not
the kernel itself.

> Since there has historically been no d-i support for Xen (and still
> isn't for 64 bit) some users will be using constructing a domU using
> tools such as xen-tools or debootstrap (I'm sure there are others). In
> that case I'd expect them to get the -xen-686 image since the paravirt
> ops stuff hasn't propagated to all those tools yet.

Neither debootstrap nor xen-tools (at least the etch version) do install
a kernel AFAIK.

> I'm not so sure I agree (there are plenty of ways to end up with invalid
> grub configurations surely, installing pae on a non-pae machine for
> example) but I think given the above we have a solution which works for
> both cases anyway, so lets ignore that little disagreement...

I'm fine with this, I just want to get this bug fixed so that we can
release lenny. :-)

Cheers,
-- 
Raphaël Hertzog

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