Pkg xen devel - Nov 2014 - Bug#737613: Debian Bug 737613: Xen not loading dom0 on Jessie - FATAL error on running /etc/init.d/xen

Control: forcemerge 503287 737613

(making $subjet a bit more helpful this time too)

On Mon, Nov 24, 2014 at 05:28:59PM +0000, Ian Campbell
wrote:
> Before investigating any further can either of you confirm whether
> this still happens with the version of Xen currently in Jessie, which
> is 4.4.1-3 (and the current kernel too). That was a major version
> bump, so it is worth confirming.
Actually nevermind this. Right after hitting send a bit more googling around
the issue took me to http://osdir.com/ml/general/2013-09/msg42718.html which
reminded me about https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=503287 and
checking the original report again it appears that you are indeed running
32-bit userspace on a 64-kernel on a 64-bit Xen. Unfortunately that combination
is not supported, quoting that first link:

  The Xen i386 userspace tools cannot run on a 64-bit kernel+hypervisor
  combo.
  
  The working combinations are:
  
  64 bit hyp, 64 bit dom0 kernel, 64 bit dom0 userspace.
  64 bit hyp, 32 bit dom0 kernel, 32 bit dom0 userspace.

The failure would be the same sort of invalid ioctl error as was observed.

Sorry for not spotting this sooner. Unfortunately this is unlikely to be fixed
within Debian (it's really an upstream thing).

Now that multiarch exists I think it ought to be possible to install the 64-bit
Xen toolstack on an otherwise 32-bit dom0 userspace, but I've not tried that
myself.

Sorry again for not figuring this out before.

I'm merging this bug with the existing wishlist bug, which is tagged wontfix
I'm afraid. It occurs to me today that /etc/init.d/xen could at least try
and
detect this situation and warn about it instead of hanging.

Ian.

Hi

Thanks for that. I'm not sure exactly what I was running that was 
incorrect. I set up the system with a

apt-get install xen-system-amd64

with a source file pointing at jessie. Therefore all the xen packages 
came via this route.

What do I need to change to get 64 bit userspace? I would like to run 
64/64/64.

The documentation on line is a bit thin.

Cheers

On 24/11/14 17:41, Ian Campbell wrote:
> Control: forcemerge 503287 737613
>
> (making $subjet a bit more helpful this time too)
>
> On Mon, Nov 24, 2014 at 05:28:59PM +0000, Ian Campbell wrote:
>> Before investigating any further can either of you confirm whether
>> this still happens with the version of Xen currently in Jessie, which
>> is 4.4.1-3 (and the current kernel too). That was a major version
>> bump, so it is worth confirming.
>
> Actually nevermind this. Right after hitting send a bit more googling
around
> the issue took me to http://osdir.com/ml/general/2013-09/msg42718.html
which
> reminded me about https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=503287
and
> checking the original report again it appears that you are indeed running
> 32-bit userspace on a 64-kernel on a 64-bit Xen. Unfortunately that
combination
> is not supported, quoting that first link:
>
>    The Xen i386 userspace tools cannot run on a 64-bit kernel+hypervisor
>    combo.
>
>    The working combinations are:
>
>    64 bit hyp, 64 bit dom0 kernel, 64 bit dom0 userspace.
>    64 bit hyp, 32 bit dom0 kernel, 32 bit dom0 userspace.
>
> The failure would be the same sort of invalid ioctl error as was observed.
>
> Sorry for not spotting this sooner. Unfortunately this is unlikely to be
fixed
> within Debian (it's really an upstream thing).
>
> Now that multiarch exists I think it ought to be possible to install the
64-bit
> Xen toolstack on an otherwise 32-bit dom0 userspace, but I've not tried
that
> myself.
>
> Sorry again for not figuring this out before.
>
> I'm merging this bug with the existing wishlist bug, which is tagged
wontfix
> I'm afraid. It occurs to me today that /etc/init.d/xen could at least
try and
> detect this situation and warn about it instead of hanging.
>
> Ian.
>
-- 

Steve Hnizdur

On Wed, 2014-11-26 at 19:57 +0000, Steve Hnizdur wrote:
> Hi
> 
> Thanks for that. I'm not sure exactly what I was running that was 
> incorrect. I set up the system with a
> 
> apt-get install xen-system-amd64
> 
> with a source file pointing at jessie. Therefore all the xen packages 
> came via this route.
> 
> What do I need to change to get 64 bit userspace? I would like to run 
> 64/64/64.
Assuming you don't want to just reinstall...

That would involve doing a "cross-grade" from 32- to 64-bit userspace
using multiarch. I've seen people doing this in various blog posts and
things but AIUI is not for the faint of heart and I expect it isn't
strictly speaking "Supported".

Oh, it's even on the wiki: https://wiki.debian.org/CrossGrading and
there are some links to blog posts at the bottom, maybe it's not as
scary as I imagined.

If your real aim is just to install the amd64 Xen tools bits and not to
replace your entire userspace then I think (but I've never tried it) you
could enable amd64 as a foreign arch (as that wiki page describes) and
then just apt-get install the Xen related packages with the :amd64
suffix to force it to reinstall those as amd64.

Ian.