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

["Goel, Sameer" <sgoel@xxxxxxxxxxxxxx>]

On 6/9/2017 5:15 AM, 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.
> 
Appreciate the feedback Robin. I will try to incorporate the new IORT changes 
when I release the first patch set.  
> Robin.
> 
> [1]:http://www.spinics.net/lists/linux-acpi/msg74844.html
> 
>>  
>>              node = iort_scan_node(ACPI_IORT_NODE_PCI_ROOT_COMPLEX,
>> -                                  iort_match_node_callback, &bus->dev);
>> +                                  iort_match_node_callback, dev);
>>              if (!node)
>> -                    return NULL;
>> +                    return AE_NOT_FOUND;
>>  
>>              parent = iort_node_map_rid(node, rid, &streamid,
>>                                         IORT_IOMMU_TYPE);
>>  
>> -            ops = iort_iommu_xlate(dev, parent, streamid);
>> +            status = iort_iommu_xlate(dev, parent, streamid);
>> +
>> +            status = status ? AE_ERROR : AE_OK;
>>  
>>      } else {
>> +            status = AE_NOT_IMPLEMENTED;
>> +#if 0
>>              int i = 0;
>>  
>>              node = iort_scan_node(ACPI_IORT_NODE_NAMED_COMPONENT,
>> @@ -616,11 +655,17 @@ const struct iommu_ops *iort_iommu_configure(struct 
>> device *dev)
>>                      parent = iort_node_get_id(node, &streamid,
>>                                                IORT_IOMMU_TYPE, i++);
>>              }
>> +#endif
>>      }
>>  
>> -    return ops;
>> +    return status;
>>  }
> 

-- 
 Qualcomm Datacenter Technologies as an affiliate of Qualcomm Technologies, 
Inc. Qualcomm Technologies, Inc. is a member of the Code Aurora Forum, a Linux 
Foundation Collaborative Project.

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
https://lists.xen.org/xen-devel