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Jason Gunthorpe
101a285411
Currently a incoherent walk domain cannot be attached to a coherent capable iommu. Kevin says HW probably doesn't exist with such a mixture, but making the driver support it makes logical sense anyhow. When building the PASID entry the PWSNP (Page Walk Snoop) bit tells the HW if it should issue snoops. If the page table is cache flushed because of PT_FEAT_DMA_INCOHERENT then it is fine to set this bit to 0 even if the HW supports 1. Weaken the compatible check to permit a coherent instance to accept an incoherent table and fix the PASID table construction to set PWSNP from PT_FEAT_DMA_INCOHERENT. SVA always sets PWSNP. Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com> Signed-off-by: Jason Gunthorpe <jgg@nvidia.com> Reviewed-by: Kevin Tian <kevin.tian@intel.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.