"Michael S. Tsirkin" <[email protected]> writes: > commit 71491c54eafa ("virtio_pci: don't try to use intxif pin is zero") > breaks virtio_pci 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. > > This seems to happen because pci_dev->pin is not populated in > pci_assign_irq(). > > Which is absolutely a bug in the relevant PCI code, but it > may also affect other platforms that use of_irq_parse_and_map_pci(). > > Work around the issue in virtio for now, and let's try to fix > all affected pci systems and then we can revert this. > > Reported-by: Michael Ellerman <[email protected]> > Fixes: 71491c54eafa ("virtio_pci: don't try to use intxif pin is zero") > Cc: "Angus Chen" <[email protected]> > Signed-off-by: Michael S. Tsirkin <[email protected]> > --- > drivers/virtio/virtio_pci_common.c | 10 ++++++++-- > 1 file changed, 8 insertions(+), 2 deletions(-) > > diff --git a/drivers/virtio/virtio_pci_common.c > b/drivers/virtio/virtio_pci_common.c > index 4df77eeb4d16..6155ea4e7e4b 100644 > --- a/drivers/virtio/virtio_pci_common.c > +++ b/drivers/virtio/virtio_pci_common.c > @@ -400,6 +400,7 @@ int vp_find_vqs(struct virtio_device *vdev, unsigned int > nvqs, > struct irq_affinity *desc) > { > int err; > + u8 pin = 0; > > /* Try MSI-X with one vector per queue. */ > err = vp_find_vqs_msix(vdev, nvqs, vqs, callbacks, names, true, ctx, > desc); > @@ -409,8 +410,13 @@ int vp_find_vqs(struct virtio_device *vdev, unsigned int > nvqs, > err = vp_find_vqs_msix(vdev, nvqs, vqs, callbacks, names, false, ctx, > desc); > if (!err) > return 0; > - /* Is there an interrupt pin? If not give up. */ > - if (!(to_vp_device(vdev)->pci_dev->pin)) > + /* > + * Is there an interrupt pin? If not give up. > + * NB: It would seem to be better to use pci_dev->pin - unfortunately > + * not all platforms populate it. > + */ > + pci_read_config_byte(dev, PCI_INTERRUPT_PIN, &pin); > + if (!pin) > return err; > /* Finally fall back to regular interrupts. */ > return vp_find_vqs_intx(vdev, nvqs, vqs, callbacks, names, ctx);
Needs the delta below in order to compile. But with that it fixes the issue for me. Tested-by: Michael Ellerman <[email protected]> cheers diff --git a/drivers/virtio/virtio_pci_common.c b/drivers/virtio/virtio_pci_common.c index 6155ea4e7e4b..cae134e2573f 100644 --- a/drivers/virtio/virtio_pci_common.c +++ b/drivers/virtio/virtio_pci_common.c @@ -415,7 +415,7 @@ int vp_find_vqs(struct virtio_device *vdev, unsigned int nvqs, * NB: It would seem to be better to use pci_dev->pin - unfortunately * not all platforms populate it. */ - pci_read_config_byte(dev, PCI_INTERRUPT_PIN, &pin); + pci_read_config_byte(to_vp_device(vdev)->pci_dev, PCI_INTERRUPT_PIN, &pin); if (!pin) return err; /* Finally fall back to regular interrupts. */ _______________________________________________ Virtualization mailing list [email protected] https://lists.linuxfoundation.org/mailman/listinfo/virtualization
