IOMMU user API header was introduced to support nested DMA translation and related fault handling. The current UAPI data structures consist of three areas that cover the interactions between host kernel and guest: - fault handling - cache invalidation - bind guest page tables, i.e. guest PASID
Future extensions are likely to support more architectures and vIOMMU features. In the previous discussion, using user-filled data size and feature flags is made a preferred approach over a unified version number. https://lkml.org/lkml/2020/1/29/45 In addition to introduce argsz field to data structures, this patchset is also trying to document the UAPI design, usage, and extension rules. VT-d driver changes to utilize the new argsz field is included, VFIO usage is to follow. Thanks, Jacob Changeog: v3: - Rewrote backward compatibility rule to support existing code re-compiled with newer kernel UAPI header that runs on older kernel. Based on review comment from Alex W. https://lore.kernel.org/linux-iommu/20200611094741.6d118...@w520.home/ - Take user pointer directly in UAPI functions. Perform argsz check and copy_from_user() in IOMMU driver. Eliminate the need for VFIO or other upper layer to parse IOMMU data. - Create wrapper function for in-kernel users of UAPI functions v2: - Removed unified API version and helper - Introduced argsz for each UAPI data - Introduced UAPI doc Jacob Pan (5): docs: IOMMU user API iommu/uapi: Add argsz for user filled data iommu/uapi: Use named union for user data iommu/uapi: Handle data and argsz filled by users iommu/uapi: Support both kernel and user unbind guest PASID Documentation/userspace-api/iommu.rst | 244 ++++++++++++++++++++++++++++++++++ drivers/iommu/intel/iommu.c | 24 ++-- drivers/iommu/intel/svm.c | 5 +- drivers/iommu/iommu.c | 138 +++++++++++++++++-- include/linux/iommu.h | 20 ++- include/uapi/linux/iommu.h | 10 +- 6 files changed, 413 insertions(+), 28 deletions(-) create mode 100644 Documentation/userspace-api/iommu.rst -- 2.7.4 _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu
