Re: pv-ops domU not working with MSI interrupts on Nehalem

[Konrad Rzeszutek Wilk <konrad.wilk@Oracle.Com>]

On Mon, Sep 27, 2010 at 08:52:39AM -0700, Bruce Edge wrote:
> One of our developers who is working on a tachyon driver is
> complaining that the pvops domU kernel is not working for these MSI
> interrupts.
> This is using the current head of xen/2.6.32.x on both a single
> Nahelam 920 and a dual E5540. This behavior is consistent with Xen
> 4.0.1, 4.0.2.rc1-pre and 4.1.
> 
> Here are his comments:
> 
> - the driver has no problem to enable msi interrupt and request the
> interrupt through kernel functions pci_enable_msi & request_irq

What shows up in the Xen console when you send the 'q' key? Does it
show that the vector is assigned to the appropiate guest?

> - the interrupt does happen. But the interrupt service routine of
> tachyon driver doesn't detect any interrupt status related to this
> interrupt, which inhibits the tachyon chip from coming on-line. And
> there are high count of tachyon interrupt in /proc/interrupts

Is it checking the PCI_STATUS_INTERRUPT or the appropiate register
in the MMIO BAR?

> 
> kaan-18-dpm:~# cat /proc/interrupts | grep TACH
> 124:     760415          0          0          0          0          0
>          0          0          0          0          0          0
>     0          0  xen-pirq-pcifront-msi  HW_TACHYON
> 125:     762234          0          0          0          0          0
>          0          0          0          0          0          0
>     0          0  xen-pirq-pcifront-msi  HW_TACHYON
> 126:     764180          0          0          0          0          0
>          0          0          0          0          0          0
>     0          0  xen-pirq-pcifront-msi  HW_TACHYON
> 127:     764164          0          0          0          0          0
>          0          0          0          0          0          0
>     0          0  xen-pirq-pcifront-msi  HW_TACHYON

Can you provide the full dmesg output?