Re: PCI pass-through / MSI question: Is 30(hex) the lower limit for pirq?

[Dante Cinco <dantecinco@gmail.com>]

Pasi, Jan,

Thank for your help. Adding the extra_guest_irqs Xen boot option 
resolved the issue I was having with the 8G QLogic card in the Windows 
domU. Each of the 2 QLogic devices requires 32 IRQs when MSI-X is 
enabled so I set the value to 80 (16 extra).

Dante

On 5/28/2010 1:50 AM, Pasi Kärkkäinen wrote:
> On Fri, May 28, 2010 at 08:30:40AM +0100, Jan Beulich wrote:
>    
>>>>> On 28.05.10 at 01:29, Dante Cinco<dantecinco@gmail.com>  wrote:
>>>>>            
>>> I'm trying to bring up a Windows domU with PCI pass-through and it looks
>>> like Xen is running out of pirqs (see log below). I'm using Xen 4.0.0 and
>>> dom0 2.6.32.12 pv-ops and pci-stub to hide the PCIe device.
>>>
>>> It looks like the first available pirq is 4e(hex) and the last available is
>>> 30(hex) and after that, Xen returns an msix error. What's the consequence of
>>> running out of pirqs?
>>>        
>> Did you try the extra_guest_irqs= Xen command line option to
>> increase the number of PIRQs (defaulting to 32) for the guest?
>>
>>      
> I added this xen.gz option to:
> http://wiki.xensource.com/xenwiki/XenHypervisorBootOptions
>
> -- Pasi
>
>