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

[Tom Rotenberg <tom.rotenberg@xxxxxxxxx>]

It happens also when msi_translte = 0 , and i think that it's not
related to the MSI at all... i also checked other devices which use
MSI (like the audio device), and they worked fine.
You can take a look at the new mail i sent, which incorporates more
details about this problem.

On Wed, Nov 25, 2009 at 4:47 PM, Jiang, Yunhong <yunhong.jiang@xxxxxxxxx> wrote:
> Tom Rotenberg wrote:
>> Well, you are correct... however, the situation is that the bgefore
>> the disable the intx bit was turned off, and only after disable and
>> then re-enable it was turned on, and that's the strange part of it...
>
> You mean even if the msi_translate == 0? That's strange. If this happens only 
> under msi_translate, it is reasonable and maybe something wrong. So can you 
> give me a confirmation?
>
> --jyh
>
>>
>> On Wed, Nov 25, 2009 at 11:38 AM, Jiang, Yunhong
>> <yunhong.jiang@xxxxxxxxx> wrote:
>>> 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

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