Re: [BUG] XEN domU crash when PV grub chainloads 32-bit domU grub

[Ian Campbell <ian.campbell@citrix.com>]

On Wed, 2015-09-23 at 12:47 +0000, Andreas Sundstrom wrote:
> Citerar Ian Campbell <ian.campbell@citrix.com>:
> 
> > Along those lines, if the _host_ has buckets of RAM then might it be
> > worth
> > restricting it in case the issue is with getting MFNs which are not
> > representably by the 32-bit PV interfaces? (IIRC the limit is ~160G due
> > to
> > the size of the m2p hole, a 32-bit MFN spans 16TB so it's unlikely to
> > be
> > that).
> > 
> > Likewise maybe the issue is with full addresses which don't fit in a 32
> > -bit
> > number (which is maybe more likely to happen if grub uses a 1:1 mapping
> > like I would guess it does), so limiting the host to <4GB might also be
> > interesting?
> > 
> 
> If this was meant for me I will need more information to understand  
> what to test.
> dom0 has either 12G or 8G memory in my test machines if that makes a  
> difference.

It was, sorry for not being clear.

How much memory do the test machines have?

If it is more than 160G then try booting with "mem=160G" on the hypervisor
(not Linux) command line. You can just edit that in via grub.

Then try with mem=4G (which might require shrinking dom0 too of course).

Ian.