Hi Baolu, On Thu, 19 May 2022 14:41:06 +0800, Baolu Lu <baolu.lu@xxxxxxxxxxxxxxx> wrote: > > IOMMU group maintains a PASID array which stores the associated IOMMU > > domains. This patch introduces a helper function to do domain to PASID > > look up. It will be used by TLB flush and device-PASID attach > > verification. > > Do you really need this? > > The IOMMU driver has maintained a device tracking list for each domain. > It has been used for cache invalidation when unmap() is called against > dma domain. Yes, I am aware of the device list. In v3, I stored DMA API PASID in device list of device_domain_info. Since we already have a pasid_array, Jason suggested to share the storage with the code. This helper is needed to reverse look up the DMA PASID based on the domain attached. Discussions here: https://lore.kernel.org/lkml/20220511170025.GF49344@xxxxxxxxxx/t/#mf7cb7d54d89e6e732a020dc22435260da0a49580 Thanks, Jacob
