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Intel ENQCMD requires a single PASID to be shared between multiple devices, as the PASID is stored in a single MSR register per-process and userspace can use only that one PASID. This means that the PASID allocation for any ENQCMD using device driver must always come from a shared global pool, regardless of what kind of domain the PASID will be used with. Split the code for the global PASID allocator into iommu_alloc/free_global_pasid() so that drivers can attach non-SVA domains to PASIDs as well. This patch moves global PASID allocation APIs from SVA to IOMMU APIs. Reserved PASIDs, currently only RID_PASID, are excluded from the global PASID allocation. It is expected that device drivers will use the allocated PASIDs to attach to appropriate IOMMU domains for use. Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com> Reviewed-by: Kevin Tian <kevin.tian@intel.com> Reviewed-by: Jason Gunthorpe <jgg@nvidia.com> Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com> Link: https://lore.kernel.org/r/20230802212427.1497170-3-jacob.jun.pan@linux.intel.com Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com> Signed-off-by: Joerg Roedel <jroedel@suse.de>
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.