WARNING - OLD ARCHIVES

This is an archived copy of the Xen.org mailing list, which we have preserved to ensure that existing links to archives are not broken. The live archive, which contains the latest emails, can be found at http://lists.xen.org/
   
 
 
Xen 
 
Home Products Support Community News
 
   
 

xen-devel

RE: [Xen-devel] Bug when disabling/enabling a PT device with MSI enabled

To: Tom Rotenberg <tom.rotenberg@xxxxxxxxx>
Subject: RE: [Xen-devel] Bug when disabling/enabling a PT device with MSI enabled
From: "Jiang, Yunhong" <yunhong.jiang@xxxxxxxxx>
Date: Wed, 25 Nov 2009 17:38:42 +0800
Accept-language: en-US
Acceptlanguage: en-US
Cc: "xen-devel@xxxxxxxxxxxxxxxxxxx" <xen-devel@xxxxxxxxxxxxxxxxxxx>, Kamala Narasimhan <Kamala.Narasimhan@xxxxxxxxxx>
Delivery-date: Wed, 25 Nov 2009 01:41:11 -0800
Envelope-to: www-data@xxxxxxxxxxxxxxxxxxx
In-reply-to: <8686c3cd0911250129t5292d204r268840cdb01d4257@xxxxxxxxxxxxxx>
List-help: <mailto:xen-devel-request@lists.xensource.com?subject=help>
List-id: Xen developer discussion <xen-devel.lists.xensource.com>
List-post: <mailto:xen-devel@lists.xensource.com>
List-subscribe: <http://lists.xensource.com/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=subscribe>
List-unsubscribe: <http://lists.xensource.com/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=unsubscribe>
References: <8686c3cd0911241042n1b6f84a9u3623518baa021cc2@xxxxxxxxxxxxxx> <5997D0BE578D47409D1EBD41DFD341F489F5F54E84@xxxxxxxxxxxxxxxxxxxxxxxxx> <8686c3cd0911250027g696b8222qc5d3b1f4a39265ef@xxxxxxxxxxxxxx> <E2263E4A5B2284449EEBD0AAB751098418E57406D9@xxxxxxxxxxxxxxxxxxxxxxxxxxxx> <E2263E4A5B2284449EEBD0AAB751098418E57406DA@xxxxxxxxxxxxxxxxxxxxxxxxxxxx>, <8686c3cd0911250129t5292d204r268840cdb01d4257@xxxxxxxxxxxxxx>
Sender: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
Thread-index: AcptsdGAh5o0D6PcQ6qvO2CK5dOwmQAAUHFJ
Thread-topic: [Xen-devel] Bug when disabling/enabling a PT device with MSI enabled
If the msi_translate=0, why IntX bit is turned on is wrong? I assume guest 
should use intX in such situation.

--jyh
________________________________________
From: Tom Rotenberg [tom.rotenberg@xxxxxxxxx]
Sent: Wednesday, November 25, 2009 2:29 AM
To: Jiang, Yunhong
Cc: Kamala Narasimhan; xen-devel@xxxxxxxxxxxxxxxxxxx
Subject: Re: [Xen-devel] Bug when disabling/enabling a PT device with MSI       
enabled

Well, to try and see if the problem is msi related or not, i
registered the device with the option of 'msi_translate=0' to force
the use of intx instead of MSI, and i still got the problem... so i
guess it's not related to the MSI.

It looks like the IntX bit (bit 3 of status word) is runed on somehow
outside qemu, and that's the problem... could that be?

On Wed, Nov 25, 2009 at 11:17 AM, Jiang, Yunhong
<yunhong.jiang@xxxxxxxxx> wrote:
> Sorry send out the mail too quickly.
> I realized it is MSI translation when I finished first section but forgot 
> remove it, so please ignore  first section.
> You only need care about MSI translation, the code is in hw/pass-through.c.  
> You can check qemu's changelog at a8d1bd66.
>
> --jyh
> ________________________________________
> From: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx 
> [xen-devel-bounces@xxxxxxxxxxxxxxxxxxx] On Behalf Of Jiang, Yunhong 
> [yunhong.jiang@xxxxxxxxx]
> Sent: Wednesday, November 25, 2009 2:10 AM
> To: Tom Rotenberg; Kamala Narasimhan
> Cc: xen-devel@xxxxxxxxxxxxxxxxxxx
> Subject: RE: [Xen-devel] Bug when disabling/enabling a PT device with MSI     
>   enabled
>
> This should be about qemu's MSI support. The code is in qemu/hw/pt-msi.c for 
> all MSI emulation.
> Windows XP does not support MSI if I remember correctly. SO this issue should 
> be about MSI translation, i.e. guest is using IOAPIC while host is using MSI. 
> Xen hypervisor will translate the MSI to guest's IOAPIC.
>
> --jyh
> ________________________________________
> From: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx 
> [xen-devel-bounces@xxxxxxxxxxxxxxxxxxx] On Behalf Of Tom Rotenberg 
> [tom.rotenberg@xxxxxxxxx]
> Sent: Wednesday, November 25, 2009 1:27 AM
> To: Kamala Narasimhan
> Cc: xen-devel@xxxxxxxxxxxxxxxxxxx
> Subject: Re: [Xen-devel] Bug when disabling/enabling a PT device with MSI     
>   enabled
>
> Well, just tested it with the 2.6.18 latest kernel, and the bug still exists.
> Also, i think that iit's more related to how qemu handles the
> "disable/enable" of domU for PT devices with MSI... but i don't know
> where to start from? it looks like when re-enabling a PT device with
> MSI, we need qemu to re-initialize the device according to it's
> original MSI state (and not to what it was resetted before).
>
> Does anyone has any clue about it?
>
> On Wed, Nov 25, 2009 at 4:25 AM, Kamala Narasimhan
> <Kamala.Narasimhan@xxxxxxxxxx> wrote:
>>
>> Couple of questions -
>>
>> 1) What kind of device are you referring to below?  Display by any chance?
>> 2) Which tree is your dom0 kernel based on?
>>
>> There is a chance you are missing some msi patches in your dom0 kernel.  You 
>> might want to do a quick search for msi patches in 
>> http://xenbits.xen.org/staging/linux-2.6.18-xen.hg?rev=msi and see if you 
>> are missing anything obvious.  I recently encountered a similar issue in a 
>> slightly different situation, a subset of the problem was caused because of 
>> missing msi patches.
>>
>> Kamala
>>
>>> -----Original Message-----
>>> From: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx [mailto:xen-devel-
>>> bounces@xxxxxxxxxxxxxxxxxxx] On Behalf Of Tom Rotenberg
>>> Sent: Tuesday, November 24, 2009 1:43 PM
>>> To: xen-devel@xxxxxxxxxxxxxxxxxxx
>>> Subject: [Xen-devel] Bug when disabling/enabling a PT device with MSI
>>> enabled
>>>
>>> Hi,
>>>
>>> I am using the xen-3,4, and i am doing pass-through for a device with
>>> MSI enabled (the device of-course supports MSI) to a domU with Windows
>>> XP. When i disable and then re-enable the device using Windows device
>>> manager, everything looks like it's working fine, but the device seems
>>> to malfunction.
>>> After digging a little bit, i saw that the problem is, because the bit
>>> of the interrupt-status (bit 3) in the status register (offset 0x6 in
>>> the PCI config space) was turned on somehow -  this proibably caused
>>> the MSI to malfunction (because the IntX assertion was enabled - thus
>>> disabling the MSI) - and this lead to the problem i experienced.
>>>
>>> Any ideas on how to solve this issue?
>>>
>>> Tom
>>>
>>> _______________________________________________
>>> Xen-devel mailing list
>>> Xen-devel@xxxxxxxxxxxxxxxxxxx
>>> http://lists.xensource.com/xen-devel
>>
>
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@xxxxxxxxxxxxxxxxxxx
> http://lists.xensource.com/xen-devel
>
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@xxxxxxxxxxxxxxxxxxx
> http://lists.xensource.com/xen-devel
>

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel