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Define idxd_copy_cr() to copy completion record to fault address in user address that is found by work queue (wq) and PASID. It will be used to write the user's completion record that the hardware device is not able to write due to user completion record page fault. An xarray is added to associate the PASID and mm with the struct idxd_user_context so mm can be found by PASID and wq. It is called when handling the completion record fault in a kernel thread context. Switch to the mm using kthread_use_vm() and copy the completion record to the mm via copy_to_user(). Once the copy is completed, switch back to the current mm using kthread_unuse_mm(). Suggested-by: Christoph Hellwig <hch@infradead.org> Suggested-by: Jason Gunthorpe <jgg@nvidia.com> Suggested-by: Tony Luck <tony.luck@intel.com> Tested-by: Tony Zhu <tony.zhu@intel.com> Signed-off-by: Fenghua Yu <fenghua.yu@intel.com> Reviewed-by: Dave Jiang <dave.jiang@intel.com> Link: https://lore.kernel.org/r/20230407203143.2189681-9-fenghua.yu@intel.com Signed-off-by: Vinod Koul <vkoul@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 Restructured Text 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.