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
With future extension in mind, the UAPI structures passed from user to kernel always starts with a mandatory version field (u32). While this is flexible for extensions of individual structures, it is difficult to maintain support of combinations of different version numbers. This patchset introduces a unified UAPI version number that governs all the UAPI data structure versions. When userspace query UAPI version for check on compatibility, a single match would be sufficient. After UAPI version check, users such as VFIO can also retrieve the matching data structure size based on version and type. Kernel IOMMU UAPI support is always backward compatible. Data structures are also only open to extension and closed to modifications. The introduction of UAPI version does not change the existing UAPI but rather simplify the data structure version and size matching. Thanks, Jacob Jacob Pan (3): iommu/uapi: Define uapi version and capabilities iommu/uapi: Use unified UAPI version iommu/uapi: Add helper function for size lookup drivers/iommu/intel-iommu.c | 3 ++- drivers/iommu/intel-svm.c | 2 +- drivers/iommu/iommu.c | 25 +++++++++++++++++++- include/linux/iommu.h | 6 +++++ include/uapi/linux/iommu.h | 57 ++++++++++++++++++++++++++++++++++++++++----- 5 files changed, 84 insertions(+), 9 deletions(-) -- 2.7.4 _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu
