Re: L1[0x1fb] = 0000000000000000 which faults on one type of machine but on another works?

[Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>]

On Thu, Mar 17, 2011 at 11:52:12AM -0400, Konrad Rzeszutek Wilk wrote:
> On Thu, Mar 17, 2011 at 10:25:11AM +0000, Jan Beulich wrote:
> > >>> On 16.03.11 at 23:19, Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> wrote:
> > > But one thing I can't understand is why on one machine (IBM x3850)
> > > I get this crash, while another one with the same pagetable contents
> > > (L1 has nothing for 0x1fb) it works just fine? I added a panic and used
> > > the Xen hypervisor kdb to manually inspect the pagetable, and it has
> > > the same contents as the IBM x3850 -but it boots fine with this invalid 
> > > value.
> > > Any ideas?
> > 
> > Without seeing the full stack trace it's hard to tell. To me, it looks
> > like a mistake for native_apic_read() to be called at all under Xen,
> > and perhaps there's one lurking somewhere that gets hit only on
> > those IBM (Summit?) machines.
> 
> That was it. When we bootup we call 'set_xen_basic_apic_ops' which

Forgot to mention it but thank you for steering me in the right direction!

The patches are in
 git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen.git for-2.6.32/bug-fixes