Re: Dom0 PAE panic when starting xend

[Christoph Egger <Christoph_Egger%gmx.de@localhost>]

On Tuesday 10 March 2009 17:21:02 Manuel Bouyer wrote:
> 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.

I just tried with casting to paddr_t. Unfortunately, this doesn't fix
the mmu_update failure. xenevtmmap() runs twice before the
panic happens.

Christoph