Re: [Qemu-devel] [PATCH v3] pci : Add pba_offset PCI quirk for Chelsio T5 devices

[Alex Williamson <alex.williamson@redhat.com>]

On Tue, 2015-06-30 at 17:58 -0400, Bandan Das wrote:
> Gabriel Laupre <glaupre@chelsio.com> writes:
> ...
> > +    /* Test the size of the pba variables and catch if they extend outside of
> > +     * the specified BAR. If it is the case, we have a broken configuration or
> > +     * we need to apply a hardware specific quirk. */
> > +    if (vdev->msix->table_offset >=
> > +        vdev->bars[vdev->msix->table_bar].region.size ||
> > +        vdev->msix->pba_offset >=
> > +        vdev->bars[vdev->msix->pba_bar].region.size) {
> > +
> > +        PCIDevice *pdev = &vdev->pdev;
> > +        uint16_t vendor = pci_get_word(pdev->config + PCI_VENDOR_ID);
> > +        uint16_t device = pci_get_word(pdev->config + PCI_DEVICE_ID);
> > +
> > +        /* Chelsio T5 Virtual Function devices are encoded as 0x58xx for T5
> > +         * adapters. The T5 hardware returns an incorrect value of 0x8000 for
> > +         * the VF PBA offset. The correct value is 0x1000, so we hard code that
> > +         * here. */
> > +        if (vendor == PCI_VENDOR_ID_CHELSIO && (device & 0xff00) == 0x5800) {
> > +            vdev->msix->pba_offset = 0x1000;
> 
> For the rare case where table_offset is wrong for the device being checked for
> above and pba_offset is actually correct, shouldn't we fail ?
> 
> > +        } else {
> > +            error_report("vfio: Hardware reports invalid configuration, "
> > +            "MSIX data outside of specified BAR");
> 
> Since we are printing anyway, and we have already made the check above, why
> not print exactly what's wrong instead of "MSIX data" ?

Probably diminishing returns to get too specific, we just need to know
that it's a hardware bug.  If we want the test to be more thorough, it
should be extracted from msix_init() so we're not duplicating code.
Thanks,

Alex

> > +            return -EINVAL;
> > +        }
> > +    }
> > +
> >      trace_vfio_early_setup_msix(vdev->vbasedev.name, pos,
> >                                  vdev->msix->table_bar,
> >                                  vdev->msix->table_offset,
> > diff --git a/include/hw/pci/pci_ids.h b/include/hw/pci/pci_ids.h
> > index 49c062b..d98e6c9 100644
> > --- a/include/hw/pci/pci_ids.h
> > +++ b/include/hw/pci/pci_ids.h
> > @@ -114,6 +114,8 @@
> >  #define PCI_VENDOR_ID_ENSONIQ            0x1274
> >  #define PCI_DEVICE_ID_ENSONIQ_ES1370     0x5000
> >  
> > +#define PCI_VENDOR_ID_CHELSIO            0x1425
> > +
> >  #define PCI_VENDOR_ID_FREESCALE          0x1957
> >  #define PCI_DEVICE_ID_MPC8533E           0x0030