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

["Goel, Sameer" <sgoel@codeaurora.org>]

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.

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