diff options
| author | Jacob Pan <jacob.jun.pan@linux.intel.com> | 2023-08-09 20:47:54 +0800 |
|---|---|---|
| committer | Joerg Roedel <jroedel@suse.de> | 2023-08-09 17:44:34 +0200 |
| commit | 4298780126c298f20ae4bc8676591eaf8c48767e (patch) | |
| tree | a25d3e7d406a420a7c9454fa9f09a7d380385c26 /include/linux/iommu.h | |
| parent | 52a93d39b17dc7eb98b6aa3edb93943248e03b2f (diff) | |
iommu: Generalize PASID 0 for normal DMA w/o PASID
PCIe Process address space ID (PASID) is used to tag DMA traffic, it
provides finer grained isolation than requester ID (RID).
For each device/RID, 0 is a special PASID for the normal DMA (no
PASID). This is universal across all architectures that supports PASID,
therefore warranted to be reserved globally and declared in the common
header. Consequently, we can avoid the conflict between different PASID
use cases in the generic code. e.g. SVA and DMA API with PASIDs.
This paved away for device drivers to choose global PASID policy while
continue doing normal DMA.
Noting that VT-d could support none-zero RID/NO_PASID, but currently not
used.
Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
Link: https://lore.kernel.org/r/20230802212427.1497170-2-jacob.jun.pan@linux.intel.com
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Diffstat (limited to 'include/linux/iommu.h')
| -rw-r--r-- | include/linux/iommu.h | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/include/linux/iommu.h b/include/linux/iommu.h index d31642596675..2870bc29d456 100644 --- a/include/linux/iommu.h +++ b/include/linux/iommu.h @@ -196,6 +196,7 @@ enum iommu_dev_features { IOMMU_DEV_FEAT_IOPF, }; +#define IOMMU_NO_PASID (0U) /* Reserved for DMA w/o PASID */ #define IOMMU_PASID_INVALID (-1U) typedef unsigned int ioasid_t; |