Re: [Xen-devel] [RFC 6/6] acpi:arm64: Add support for parsing IORT table

[Julien Grall <julien.grall@xxxxxxx>]

(CC x86 folks)

Hi,

On 09/06/17 12:15, Robin Murphy wrote:
> On 08/06/17 20:30, Sameer Goel wrote:
> [...]
> >  /**
> > - * iort_iommu_configure - Set-up IOMMU configuration for a device.
> > + * iort_iommu_configure - Set-up IOMMU configuration for a device. This
> > + * function sets up the fwspec as needed for a given device. Only PCI
> > + * devices are supported for now.
> >   *
> >   * @dev: device to configure
> >   *
> > - * Returns: iommu_ops pointer on configuration success
> > - *          NULL on configuration failure
> > + * Returns: Appropriate acpi_status
> >   */
> > -const struct iommu_ops *iort_iommu_configure(struct device *dev)
> > +acpi_status iort_iommu_configure(struct device *dev)
> >  {
> >         struct acpi_iort_node *node, *parent;
> > -       const struct iommu_ops *ops = NULL;
> >         u32 streamid = 0;
> > +       acpi_status status = AE_OK;
> >
> >         if (dev_is_pci(dev)) {
> > -               struct pci_bus *bus = to_pci_dev(dev)->bus;
> > +               struct pci_dev *pci_device = to_pci_dev(dev);
> >                 u32 rid;
> >
> > -               pci_for_each_dma_alias(to_pci_dev(dev), __get_pci_rid,
> > -                                      &rid);
> > +               rid = PCI_BDF2(pci_device->bus,pci_device->devfn);
> Beware that the Linux code isn't actually correct to begin with[1]. I
> don't know how much Xen deals with PCI bridges and quirks, but as it
> stands you should be able to trivially expose the flaw here by plugging
> in a Marvell 88SE912x-based SATA card and watching either DMA or MSIs
> (or even both) kick up stream table faults.
>
> Robin.
>
> [1]:http://www.spinics.net/lists/linux-acpi/msg74844.html
I am not sure how x86 is handling that. The closest I can find would be 
domain_context_mapping. I have CCed x86 folks to get more feedback here.
Cheers,

--
Julien Grall

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