Re: [PATCH v3 04/13] xen/arm: support for guest SGI

[Sander Bogaert <sander.bogaert@gmail.com>]

On 26-04-13 15:35, Julien Grall wrote:
> On 04/26/2013 02:24 PM, Ian Campbell wrote:
> 
>> On Fri, 2013-04-26 at 13:12 +0100, Sander Bogaert wrote:
>>> I've been running crashme ( executing random instructions ) on Xen on
>>> Arm installed on an Arndale board. I'm using Julien's dom0 and Xen
>>> branch. The Xen branch wasn't updated in a few days.
>>>
>>> I managed to crash Xen from dom0 userspace:
>>> (XEN)
>>> (XEN) ****************************************
>>> (XEN) Panic on CPU 1:
>>> (XEN) Unhandled SGI 2 on CPU1
>>> (XEN) ****************************************
>>> (XEN)
>>> (XEN) Reboot in five seconds...
>>>
>>> Tracking this back to the source:
>>> xen/arch/arm/gic.c:648 static void do_sgi
>>> xen/arch/arm/gic.c:671 void gic_interrupt
>>>
>>> From what I understood from the source all sgi's except 0 & 1
>>> would/will cause this panic since they are just not handled.
>>
>> Do you know how the SGI was triggered, because if guest/dom0 userspace
>> can trigger an arbitrary SGI then we have big problems!
>>
>> Julien, does your tree have anything in it which might explain this?
> 
> 
> This SGI should only be triggered to call a function on another CPU. But
> it seems his xen tree doesn't have the patch applied. So nobody should
> call this SGI.
> 

I've been using 5ce4118f5768c6137d58888d57972bdfdf4c9aba in the branch
'arndale' on this repo:
git://xenbits.xen.org/people/julieng/xen-unstable.git .

I will try to reproduce this, I did log my initial seed for crashme and
the ones leading up to the crash. Is there something I can enable to get
some more output? I thought Xen would print some data ( I've seen that
before, the register content & such + a stacktrace ).

I should have started a new thread for this, I thought it was related to
what this patch fixes.

Sander