Re: Xen 4.0 crashes with pvops kernel

[Cris Daniluk <cris.daniluk@gmail.com>]

On Tue, Jun 15, 2010 at 9:20 AM, Jan Beulich <JBeulich@novell.com> wrote:
>>>> On 15.06.10 at 14:56, Keir Fraser <keir.fraser@eu.citrix.com> wrote:
>> On 15/06/2010 13:50, "Jan Beulich" <JBeulich@novell.com> wrote:
>>
>>>
>>> Keir, assuming these are reads only, would it make sense to permit
>>> Dom0 to map the IO-APIC space read-only? Perhaps even
>>> transparently converting writeable mappings to read-only ones
>>> (since drivers/acpi/osl.c tries to establish writeable mappings
>>> irrespective of the actual needs)? The obvious danger in doing
>>> so is that going forward there may appear fields in that page
>>> reads of which aren't side effect free...
>>
>> Well, how come it works with other Linux kernels -- presumably they have
>> some extra error handling in the ACPI subsystem? Shouldn't that just be
>> added to this kernel?
>
> I'm rather suspecting there's new code (compared to 2.6.18) that's
> lacking proper error handling, though I didn't look in detail so far.
>
> Hmm, looking a little more closely it seems they indeed try to write
> to that space - this we for sure can't allow. I'll see if I can follow
> the code path (unfortunately the stack trace is an imprecise one).
>
> Cris, seeing DSDT and SSDTs from that system would surely be
> helpful.
>

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.

Anyway, what is a useful format to provide those tables in? The dumps
are quite long and seem like they will format horribly via email.

Thanks for your help,

Cris