Re: [PATCH v6 1/4] iommu: Generalize default PCIe requester ID PASID

[Baolu Lu]

On 5/20/23 4:32 AM, Jacob Pan wrote:
> PCIe Process address space ID (PASID) is used to tag DMA traffic, it
> provides finer grained isolation than requester ID (RID).
>
> For each RID, 0 is as a special PASID for the legacy DMA (without
> PASID), thus RID_PASID. This is universal across all architectures,
> therefore warranted to be declared in the common header.
> Noting that VT-d could support none-zero RID_PASID, but currently not
> used.
>
> By having a common RID_PASID, we can avoid conflicts between different
> use cases in the generic code. e.g. SVA and DMA API with PASIDs.
>
> Signed-off-by: Jacob Pan<jacob.jun.pan@xxxxxxxxxxxxxxx>

Reviewed-by: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx>

Best regards,
baolu