On Thu, 2012-05-31 at 15:47 -0400, Don Dutile wrote:
> On 05/30/2012 04:19 PM, Alex Williamson wrote:
> > Work around broken devices and adhere to ACS support when determining
> > IOMMU grouping.
> >
> > Signed-off-by: Alex Williamson<alex.williamson@xxxxxxxxxx>
> > ---
> >
> > drivers/iommu/intel-iommu.c | 25 +++++++++++++++++++++++++
> > 1 file changed, 25 insertions(+)
> >
> > diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
> > index 4a43452..ebf2b31 100644
> > --- a/drivers/iommu/intel-iommu.c
> > +++ b/drivers/iommu/intel-iommu.c
> > @@ -4090,6 +4090,14 @@ static int intel_iommu_domain_has_cap(struct iommu_domain *domain,
> > return 0;
> > }
> >
> > +static void swap_pci_ref(struct pci_dev **from, struct pci_dev *to)
> > +{
> > + pci_dev_put(*from);
> > + *from = to;
> > +}
> > +
> > +#define REQ_ACS_FLAGS (PCI_ACS_SV | PCI_ACS_RR | PCI_ACS_CR | PCI_ACS_UF)
> > +
> > static int intel_iommu_add_device(struct device *dev)
> > {
> > struct pci_dev *pdev = to_pci_dev(dev);
> > @@ -4112,6 +4120,23 @@ static int intel_iommu_add_device(struct device *dev)
> > } else
> > dma_pdev = pci_dev_get(pdev);
> >
> > + swap_pci_ref(&dma_pdev, pci_get_dma_source(dma_pdev));
> > +
> > + if (dma_pdev->multifunction&&
> > + !pci_acs_enabled(dma_pdev, REQ_ACS_FLAGS))
> > + swap_pci_ref(&dma_pdev,
> > + pci_get_slot(dma_pdev->bus,
> > + PCI_DEVFN(PCI_SLOT(dma_pdev->devfn),
> > + 0)));
> > +
> > + while (!pci_is_root_bus(dma_pdev->bus)) {
> > + if (pci_acs_path_enabled(dma_pdev->bus->self,
> > + NULL, REQ_ACS_FLAGS))
> > + break;
> > +
> > + swap_pci_ref(&dma_pdev, pci_dev_get(dma_pdev->bus->self));
> > + }
> > +
> I'm having deja-vu on this patch....
> .... why not just make the above two patches as two functions in drivers/iommu/iommu.c,
> one exported for these two modules (and maybe others someday...), e.g., iommu_pdev_put())
> which [intel-,amd-]iommu.c call ?
Do we want to put PCI specific code in the IOMMU base code? I think
we'd want to avoid that. I have no objection to reducing the
duplication, but I'm not sure who else is going to use this, where to
put it and what to call it. So, I left the duplication here so it might
get more review from the IOMMU driver maintainers. Thanks,
Alex
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