Re: Dom0 PAE panic when starting xend

[Manuel Bouyer <bouyer%antioche.eu.org@localhost>]

On Tue, Mar 10, 2009 at 05:14:03PM +0100, Christoph Egger wrote:
> > Good catch; x86_btop() needs to be fixed as it could break other
> > things. For the problem to show up you need to have 4G or more RAM though
> > (which might also explain why it doesn't cause problems for some).
> >
> > The problem is that x86_btop() is used for both physical and virtual
> > addresses, which doesn't fit very well PAE. Maybe just casting to paddr_t
> > would be good enough ...
> 
> My machine has exactly 4GB RAM.

OK, so that's most likely it. With a PCI hole of 768M or more (that's what I
see on hardware I have) you have about 3/4G or ram above the 4GB barrier.
I'll also add that Xen likes to allocate memory
top-down, so in such a configuration dom0 is likely getting most of its
RAM (if not all) above the 4GB barrier.

-- 
Manuel Bouyer, LIP6, Universite Paris VI.           
Manuel.Bouyer%lip6.fr@localhost
     NetBSD: 26 ans d'experience feront toujours la difference
--