Messages in this thread | | | From | "Tian, Kevin" <> | Subject | RE: [PATCH v5 1/7] iommu: Generalize default PCIe requester ID PASID | Date | Fri, 28 Apr 2023 09:38:32 +0000 |
| |
> From: Jacob Pan <jacob.jun.pan@linux.intel.com> > Sent: Friday, April 28, 2023 1:50 AM > > 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.
You intend it to be generic but in the end only vt-d driver is changed to use it in this series...
> @@ -190,6 +190,7 @@ enum iommu_dev_features { > IOMMU_DEV_FEAT_IOPF, > }; > > +#define IOMMU_DEF_RID_PASID (0U) /* Reserved for DMA w/o PASID > */
Is RID a general team on other platform?
Would IOMMU_DEF_NO_PASID serve the purpose better?
| |