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    iommu: Add I/O ASID allocator · fa83433c
    Jean-Philippe Brucker 提交于
    Some devices might support multiple DMA address spaces, in particular
    those that have the PCI PASID feature. PASID (Process Address Space ID)
    allows to share process address spaces with devices (SVA), partition a
    device into VM-assignable entities (VFIO mdev) or simply provide
    multiple DMA address space to kernel drivers. Add a global PASID
    allocator usable by different drivers at the same time. Name it I/O ASID
    to avoid confusion with ASIDs allocated by arch code, which are usually
    a separate ID space.
    
    The IOASID space is global. Each device can have its own PASID space,
    but by convention the IOMMU ended up having a global PASID space, so
    that with SVA, each mm_struct is associated to a single PASID.
    
    The allocator is primarily used by IOMMU subsystem but in rare occasions
    drivers would like to allocate PASIDs for devices that aren't managed by
    an IOMMU, using the same ID space as IOMMU.
    Signed-off-by: NJean-Philippe Brucker <jean-philippe.brucker@arm.com>
    Signed-off-by: NJacob Pan <jacob.jun.pan@linux.intel.com>
    Reviewed-by: NJean-Philippe Brucker <jean-philippe@linaro.org>
    Reviewed-by: NEric Auger <eric.auger@redhat.com>
    Signed-off-by: NJoerg Roedel <jroedel@suse.de>
    fa83433c
Makefile 1.7 KB