Re: Fwd: Re: Xen 4.3 / 4.4 - concurrent APIs, VGA Passthru

[Gordan Bobic <gordan@bobich.net>]

On 2014-07-29 12:52, Georg Bege wrote:
> Am 29.07.2014 12:38, schrieb Gordan Bobic:
>> On 2014-07-29 08:39, Georg Bege wrote:
>>> Am 29.07.2014 09:10, schrieb Gordan Bobic:
>>>> On 07/29/2014 02:12 AM, Georg Bege wrote:

>>>>> no with Xen 4.3 its not working to me, in Win XP64 I get kinda
>>>>> abstract
>>>>> distortions in the screen,
>>>> 
>>>> That sounds suspiciously like the IOMEM memory stomp I see with my
>>>> motherboard.
>>>> 
>>>>> not much later then I get a kernel panic on Dom0 regarding IRQ16 
>>>>> (like
>>>>> sth IRC16: no body cared.. oops) the kernel gets damaged by it and
>>>>> then
>>>>> the whole machine works like in slow-motion (everything X11, moving 
>>>>> of
>>>>> the mouse etc.) all I can do then is hard reboot...
>>>> 
>>>> I have seen the interrupt issue before but _only_ when I xl destroy
>>>> the domUs. It never happened on a clean shutdown/reboot of domUs. 
>>>> The
>>>> interrupt you mention - does it happen to be the IRQ used by your 
>>>> USB
>>>> controller?
>>> Im not sure but the IRQ 16 is used by:
>>>  16:    2065542          0          0          0          0
>>> 0          0          0  xen-pirq-ioapic-level  ehci_hcd:usb1,
>>> snd_emu10k1, nouveau
>> 
>> ehci_hcd:usb1 sounds like USB.
>> 
>> If you look at lspci -vvv, look for "IRQ 16". It should match.
>> 
> Yes you're right, it is - however Im quite suprised how many devices
> share that same Interrupt.
> 
> Interrupt: pin A routed to IRQ 16:
> 
> 00:1a.0 USB controller: Intel Corporation C600/X79 series chipset USB2
> Enhanced Host Controller #2 (rev 05) (prog-if 20 [EHCI])
> 02:00.0 USB controller: NEC Corporation uPD720200 USB 3.0 Host
> Controller (rev 04) (prog-if 30 [XHCI])
> 03:00.0 VGA compatible controller: NVIDIA Corporation GF100GL [Quadro
> 5000] (rev a3) (prog-if 00 [VGA controller])
> 04:00.0 VGA compatible controller: NVIDIA Corporation GT218 [GeForce
> 210] (rev a2) (prog-if 00 [VGA controller])
> 05:00.0 Serial Attached SCSI controller: LSI Logic / Symbios Logic
> SAS2008 PCI-Express Fusion-MPT SAS-2 [Falcon] (rev 03)
> 0a:00.0 Multimedia audio controller: Creative Labs SB Live! EMU10k1 
> (rev 04)
> 
> Is this normal?

It sounds a bit high, but it's not implausible.

On my machine this shows:
for irq in `lspci -vvv | grep IRQ | sed -e 's/.*IRQ //' | sort -un`; do
   echo -n "IRQ $irq: ";
   lspci -vvv | grep IRQ | sed -e 's/.*IRQ //' | grep "^$irq$" | wc -l;
done

IRQ 16: 1
IRQ 18: 3
IRQ 19: 2
IRQ 21: 1
IRQ 22: 1
IRQ 23: 2
IRQ 24: 2
IRQ 29: 1
IRQ 36: 1
IRQ 37: 1
IRQ 38: 1
IRQ 39: 1
IRQ 40: 1
IRQ 212: 1
IRQ 213: 1
IRQ 214: 1
IRQ 215: 1

So IRQ 18 is used by 3 devices, all of which are on the
ICH10 SB chip (2x USB, 1x SMBus).

What surprises me slightly more is the devices that are
sharing IRQs on your system. It almost looks like at least 4
PCIe slots are sharing the same interrupt, which is somewhat
unusual.

> I've to check out the other stuff, I'll reply again once I did that -
> but might take till tomorrow.

Please do. I'd be interested to hear if you are in fact
hitting the same bug as me, as it is rather obscure and
unusual.

Gordan