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

[Julien Grall <julien.grall@xxxxxxxxxx>]

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.

-- 
Julien

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