RE: [GIT PULL] virtio: fixes, features

[Angus Chen]

> -----Original Message-----
> From: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
> Sent: Wednesday, October 12, 2022 2:21 PM
> To: Michael S. Tsirkin <mst@xxxxxxxxxx>
> Cc: kvm@xxxxxxxxxxxxxxx; virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx;
> netdev@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx;
> alvaro.karsz@xxxxxxxxxxxxx; Angus Chen <angus.chen@xxxxxxxxxxxxxxx>;
> gavinl@xxxxxxxxxx; jasowang@xxxxxxxxxx; lingshan.zhu@xxxxxxxxx;
> mst@xxxxxxxxxx; wangdeming@xxxxxxxxxx; xiujianfeng@xxxxxxxxxx;
> linuxppc-dev@xxxxxxxxxxxxxxxx; Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
> Subject: Re: [GIT PULL] virtio: fixes, features
> 
> "Michael S. Tsirkin" <mst@xxxxxxxxxx> writes:
> > The following changes since commit
> 4fe89d07dcc2804c8b562f6c7896a45643d34b2f:
> >
> >   Linux 6.0 (2022-10-02 14:09:07 -0700)
> >
> > are available in the Git repository at:
> >
> >   https://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost.git
> tags/for_linus
> >
> > for you to fetch changes up to
> 71491c54eafa318fdd24a1f26a1c82b28e1ac21d:
> >
> >   virtio_pci: don't try to use intxif pin is zero (2022-10-07 20:00:44 -0400)
> >
> > ----------------------------------------------------------------
> > virtio: fixes, features
> >
> > 9k mtu perf improvements
> > vdpa feature provisioning
> > virtio blk SECURE ERASE support
> >
> > Fixes, cleanups all over the place.
> >
> > Signed-off-by: Michael S. Tsirkin <mst@xxxxxxxxxx>
> >
> > ----------------------------------------------------------------
> > Alvaro Karsz (1):
> >       virtio_blk: add SECURE ERASE command support
> >
> > Angus Chen (1):
> >       virtio_pci: don't try to use intxif pin is zero
> 
> This commit breaks virtio_pci for me on powerpc, when running as a qemu
> guest.
> 
> vp_find_vqs() bails out because pci_dev->pin == 0.
> 
> But pci_dev->irq is populated correctly, so vp_find_vqs_intx() would
> succeed if we called it - which is what the code used to do.
> 
> I think this happens because pci_dev->pin is not populated in
> pci_assign_irq().
> 
> I would absolutely believe this is bug in our PCI code, but I think it
> may also affect other platforms that use of_irq_parse_and_map_pci().
> 
> cheers
HI,sorry for reply again. If I change the code like blew:
 pci_read_config_byte(dev, PCI_INTERRUPT_PIN, &pin);
 if (!pin) {
        warn_on("some thing");
         return 0;
        }
It will fix the orign bug.
Or we should populated the pci_dev->pin value correctly according to PCI spec about "Interrupt Pin" Register.

I have no idea about it, any suggestions are welcome.
Thank you.