Re: Xen 4.0 crashes with pvops kernel

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

On Tue, Jun 15, 2010 at 05:17:15PM +0300, Pasi Kärkkäinen wrote:
> On Tue, Jun 15, 2010 at 02:43:56PM +0100, Jan Beulich wrote:
> > >>> On 15.06.10 at 15:24, Cris Daniluk <cris.daniluk@gmail.com> wrote:
> > > For what its worth, it happened in 2.6.32.11 in addition to 2.6.32.13.
> > > I also had earlier tried a 2.6.31 pvops distro kernel with the same
> > > results last week. Interestingly, I also tried a 2.6.31 kernel with
> > > Xen 3.4 on the same hardware with no issues. It seems like XenLinux
> > > kernel with Xen 4.0 is fine, and pvops with Xen 3.x is fine.
> > 
> > That's odd, but perhaps the kernel behaves differently on older Xen.
> > Attempts to map IO-APIC space should be disallowed by 3.4 just as
> > with 4.0.
> >  
> 
> At least Xen 4.0 has the new IOAPIC hypercall that pvops 2.6.32 is using..

Yes and no. There are actually two ways of doing this: Using the
xen_acpi_register_gsi (or something akin to this) that makes a hypercall
to set the polarity/level of the IRQ. Then there is another which is to
map the IO APIC registers to dom0. The later is still present in 2.6.31
but not in 2.6.32.The upstream community did not like that mechanism of accessing
the IO APIC registers.

Soo, thanks to Jan's excellent knowledge of the ACPI spec and figuring
out that the DSDT tries to fiddle with the IO APIC registers we know
what the failure is.

Fixing it is another problem. Jan, any suggestions? Fixing the DSDT to
not do the store?