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Add support for DMABUF MR registrations with Data-direct device. Upon userspace calling to register a DMABUF MR with the data direct bit set, the below algorithm will be followed. 1) Obtain a pinned DMABUF umem from the IB core using the user input parameters (FD, offset, length) and the DMA PF device. The DMA PF device is needed to allow the IOMMU to enable the DMA PF to access the user buffer over PCI. 2) Create a KSM MKEY by setting its entries according to the user buffer VA to IOVA mapping, with the MKEY being the data direct device-crossed MKEY. This KSM MKEY is umrable and will be used as part of the MR cache. The PD for creating it is the internal device 'data direct' kernel one. 3) Create a crossing MKEY that points to the KSM MKEY using the crossing access mode. 4) Manage the KSM MKEY by adding it to a list of 'data direct' MKEYs managed on the mlx5_ib device. 5) Return the crossing MKEY to the user, created with its supplied PD. Upon DMA PF unbind flow, the driver will revoke the KSM entries. The final deregistration will occur under the hood once the application deregisters its MKEY. Notes: - This version supports only the PINNED UMEM mode, so there is no dependency on ODP. - The IOVA supplied by the application must be system page aligned due to HW translations of KSM. - The crossing MKEY will not be umrable or part of the MR cache, as we cannot change its crossed (i.e. KSM) MKEY over UMR. Signed-off-by: Yishai Hadas <yishaih@nvidia.com> Link: https://patch.msgid.link/1f99d8020ed540d9702b9e2252a145a439609ba6.1722512548.git.leon@kernel.org Signed-off-by: Leon Romanovsky <leon@kernel.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.