From mboxrd@z Thu Jan  1 00:00:00 1970
From: Keir Fraser <keir.fraser@eu.citrix.com>
Subject: Re: xen crash related to pci passthrough
Date: Fri, 28 May 2010 10:52:59 +0100
Message-ID: <C825510B.16222%keir.fraser@eu.citrix.com>
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To: Alex Zeffertt <Alex.Zeffertt@eu.citrix.com>, Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Xen-devel <xen-devel@lists.xensource.com>, Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
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On 28/05/2010 10:28, "Alex Zeffertt" <Alex.Zeffertt@eu.citrix.com> wrote:

> This is only tangentially related, but...
> 
> In xen/arch/x86/irq.c:__pirq_guest_unbind() this code looks wrong to me:
> 
>      memmove(&action->guest[i], &action->guest[i+1], IRQ_MAX_GUESTS-i-1);
> 
> Should it be:
> 
>      memmove(&action->guest[i], &action->guest[i+1],
> sizeof(action->guest[0])*(IRQ_MAX_GUESTS-i-1));

Yes, that must be one of the oldest bugs ever!

 Thanks,
 Keir

> 
> ?
> 
> Regards,
> 
> Alex
> 
> 
> On 27/05/10 22:02, Jeremy Fitzhardinge wrote:
>> On 05/27/2010 01:02 PM, Keir Fraser wrote:
>>> On 27/05/2010 20:51, "Jeremy Fitzhardinge"<jeremy@goop.org>  wrote:
>>> 
>>> 
>>>>     3. attach device to PV domU
>>>>        dom0# xl pci-attach f13pv64 0000:03:00.0
>>>>     4. unbind from pciback
>>>>        dom0# echo 0000:03:00.0>  /sys/bus/pci/drivers/pciback/unbind
>>>>     5. rmmod driver in domU
>>>>        domU# rmmod e1000e
>>>>     6. Crash!
>>>> 
>>>> The device in question is an Intel 82574L ethernet controller, using
>>>> msi-x interrupts.
>>>> 
>>> What happens if you pci-detach before unbinding from pciback? Not that Xen
>>> should crash of course, but a crash resulting from a mistake in detach
>>> ordring in dom0 would be less worrying than some alternatives.
>>> 
>> 
>> Doing things in a more sensible order (rmmod in domU, detach, unbind)
>> seems to work OK.  I was deliberately seeing what would happen if I
>> tried pulling the device out from under a domain.
>> 
>>      J
>> 
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>