Hi Jacob, On 12/7/21 9:47 PM, Jacob Pan wrote:
DMA mapping API is the de facto standard for in-kernel DMA. It operates on a per device/RID basis which is not PASID-aware.Some modern devices such as Intel Data Streaming Accelerator, PASID is required for certain work submissions. To allow such devices use DMA mapping API, we need the following functionalities: 1. Provide device a way to retrieve a kernel PASID for work submission 2. Enable the kernel PASID on the IOMMU 3. Establish address space for the kernel PASID that matches the default domain. Let it be IOVA or physical address in case of pass-through. This patch introduces a driver facing API that enables DMA API PASID usage. Once enabled, device drivers can continue to use DMA APIs as is. There is no difference in dma_handle between without PASID and with PASID.
Can a device issue DMA requests with PASID even there's no system IOMMU or the system IOMMU is disabled? Best regards, baolu _______________________________________________ iommu mailing list [email protected] https://lists.linuxfoundation.org/mailman/listinfo/iommu
