Re: completion timeouts with pin-based interrupts in QEMU hw/nvme

[Guenter Roeck]

On 1/12/23 09:45, Klaus Jensen wrote:
> On Jan 12 09:34, Keith Busch wrote:
> > On Thu, Jan 12, 2023 at 02:10:51PM +0100, Klaus Jensen wrote:
> > > The pin-based interrupt logic in hw/nvme seems sound enough to me, so I
> > > am wondering if there is something going on with the kernel driver (but
> > > I certainly do not rule out that hw/nvme is at fault here, since
> > > pin-based interrupts has also been a source of several issues in the
> > > past).
> >
> > Does it work if you change the pci_irq_assert() back to pci_irq_pulse()?
> > While probably not the "correct" thing to do, it has better results in
> > my testing.
>
> A simple s/pci_irq_assert/pci_irq_pulse broke the device. However,
>
>         diff --git i/hw/nvme/ctrl.c w/hw/nvme/ctrl.c
>         index 03760ddeae8c..0fc46dcb9ec4 100644
>         --- i/hw/nvme/ctrl.c
>         +++ w/hw/nvme/ctrl.c
>         @@ -477,6 +477,7 @@ static void nvme_irq_check(NvmeCtrl *n)
>                  return;
>              }
>              if (~intms & n->irq_status) {
>         +        pci_irq_deassert(&n->parent_obj);
>                  pci_irq_assert(&n->parent_obj);
>              } else {
>                  pci_irq_deassert(&n->parent_obj);
>
>
> seems to do the trick (pulse is the other way around, assert, then
> deassert).
>
> Probably not the "correct" thing to do, but I'll take it since it seems
> to fix it. On a simple boot loop I got the timeout about 1 out of 5. I'm
> on ~20 runs now and have not encountered it.
>
> I'll see if I can set up a mips rootfs and test that. Guenter, what MIPS
> machine/board(s) are you testing?

See
https://github.com/groeck/linux-build-test/blob/master/rootfs/mips/run-qemu-mips.sh
and
https://github.com/groeck/linux-build-test/blob/master/rootfs/mipsel/run-qemu-mipsel.sh

I'll apply the change suggested above to my version of qemu (7.2.0)
and give it a try.

Guenter