mirror of
https://github.com/torvalds/linux.git
synced 2025-12-07 20:06:24 +00:00
36ae67b139
Some IOMMU HW cannot snoop the CPU cache when it walks the IO page tables. The CPU is required to flush the cache to make changes visible to the HW. Provide some helpers from iommu-pages to manage this. The helpers combine both the ARM and x86 (used in Intel VT-d) versions of the cache flushing under a single API. The ARM version uses the DMA API to access the cache flush on the assumption that the iommu is using a direct mapping and is already marked incoherent. The helpers will do the DMA API calls to set things up and keep track of DMA mapped folios using a bit in the ioptdesc so that unmapping on error paths is cleaner. The Intel version just calls the arch cache flush call directly and has no need to cleanup prior to destruction. Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com> Reviewed-by: Kevin Tian <kevin.tian@intel.com> Signed-off-by: Jason Gunthorpe <jgg@nvidia.com> Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
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.