Re: [Xen-devel] Re: [GIT PATCH v2 0/14] xen: events: cleanups +ween off nr_irqs

[Ian Campbell]

On Fri, 2011-03-11 at 14:29 +0000, Konrad Rzeszutek Wilk wrote:
> > > > > I am having difficulties with passthrough of an USB device. Somehow the
> > > > > irq count is not going up at all (both in dom0 and domU) and it looks to
> > > > > be doing just simple polling. I've rebased the xen-pciback to be on top
> > > > > of your changes and apply cleanly. The whole lot is now in #master
> > > > > 
> > > > > MSI and MSI-X devices work just fine in both Dom0 and DomU case so
> > > > > it is something special with the legacy IRQs. Probably forgot something
> > > > > simple...
> > > > 
> > > > Thanks, I'll take a look. Did you mean "legacy IRQ" as in <16 or as in
> > > > not-MSI(-X)?
> 
> not-MSI(-X) ones. I've this fancy LSI 1030 controller that sits at GSI 46 on this
> SuperMicro board and it is quite confused.
> > > 
> > > Works for me in a PV guest, at least under the second interpretation (I
> > > don't have any useful devices IRQ < 16). This is with your pciback 0.5.
> 
> OK. Let me boot up that machine and see what /proc/interrupts look like. Maybe
> the xen-pciback.hide=() throws a lot of things out of whack.

FWIW I'm using xen-pciback.hide too.

> > > 
> > > I see something like what you describe under HVM, although pciback is
> > > not used in that case. xc_physdev_map_pirq is used but not with
> > > the /sys/.../bdf node AFAICT.
> > > 
> > > More digging required I guess...
> > 
> > If I just pass through the EHCI device it doesn't work. However if I
> > also pass-through the associated UHCI controller then I do see the
> > usb-storage device, interrupts and all. The EHCI controller still
> > doesn't work though. Note that with a PV guest passing-through the EHCI
> > controller by itself does work.
> > 
> > The issue I'm seeing seems to have more to do with accessing the memory
> > mapped BAR than IRQs though:
> 
> > 
> >         ehci_hcd: USB 2.0 'Enhanced' Host Controller (EHCI) Driver
> >         PHYSDEVOP_map_pirq mapped gsi 46 to pirq 18
> >         xen_allocate_pirq_gsi for gsi 46, pirq 18 "ioapic-level"
> >         xen: --> irq=46, pirq=18
> >         ehci_hcd 0000:00:07.0: PCI INT C -> GSI 46 (level, low) -> IRQ 46
> >         ehci: remapped rsrc 0xf3021000 to c8064000
> 
> <scratch> If you hit the 'i' in the debug console is this 
> BAR visible there? That is f3021?

'i' is irq information not BARs, but FWIW the IRQ associated with this
H/W appears to be mapped correctly.

I couldn't find another debug key which looked like it contained the
sort of thing you meant.

Ian.

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