Re: [PATCH] x86/dpci: remove the dpci EOI timer

[Jason Andryuk <jandryuk@xxxxxxxxx>]

On Wed, Jan 13, 2021 at 1:34 PM Jason Andryuk <jandryuk@xxxxxxxxx> wrote:
>
> On Wed, Jan 13, 2021 at 1:06 PM Roger Pau Monné <roger.pau@xxxxxxxxxx> wrote:
> >
> > On Wed, Jan 13, 2021 at 10:48:52AM -0500, Jason Andryuk wrote:

<snip>

> > > I have some laptops running OpenXT where the USB controller and NIC
> > > share an interrupt, and I assign them to different domains.  Qubes
> > > would hit this as well.
> >
> > Is there any chance you could try the patch and see if you can hit the
> > issue it was trying to fix?
>
> Would testing a backport to 4.12 be useful?  There were some file
> renames, but it looks to apply.  The only difference is the 4.12
> hvm_pirq_eoi hunk still has `(ent && ent->fields.mask) || `.  Maybe
> backport commit eb298f32fac5ac "x86/dpci: EOI interrupt regardless of
> its masking status" as well?

Ok, I added these two patches to OpenXT with Xen 4.12.

> Testing staging would take a little longer to make a machine available.
>
> I guess I'd also need to disable MSI for the two devices to ensure
> they are both using the GSI?

lspci in dom0 shows the USB xhci controller, iwlwifi, and e1000e
devices all with IRQ 16 and all with MSI disabled ("MSI: Enabled-").
The two linux HVMs run with (PV) linux stubdoms, and the HVM kernels
were started with pci=nosmi.  Networking through the iwlwifi device
works for that VM while a mouse attached to the xhci controller is
also working in the second VM.  Is there something else I should test?

Regards,
Jason