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author | Jason Gunthorpe <jgg@nvidia.com> | 2022-11-29 16:29:31 -0400 |
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committer | Jason Gunthorpe <jgg@nvidia.com> | 2022-11-30 20:16:49 -0400 |
commit | f394576eb11dbcd3a740fa41e577b97f0720d26e (patch) | |
tree | 386355684d9f6aaab3a25ecfc2692bc889283694 /drivers/iommu/iommufd/iommufd_private.h | |
parent | ce5a23c835aa0f0a931b5bcde1e7811f951b0146 (diff) | |
download | linux-stable-f394576eb11dbcd3a740fa41e577b97f0720d26e.tar.gz linux-stable-f394576eb11dbcd3a740fa41e577b97f0720d26e.tar.bz2 linux-stable-f394576eb11dbcd3a740fa41e577b97f0720d26e.zip |
iommufd: PFN handling for iopt_pages
The top of the data structure provides an IO Address Space (IOAS) that is
similar to a VFIO container. The IOAS allows map/unmap of memory into
ranges of IOVA called iopt_areas. Multiple IOMMU domains (IO page tables)
and in-kernel accesses (like VFIO mdevs) can be attached to the IOAS to
access the PFNs that those IOVA areas cover.
The IO Address Space (IOAS) datastructure is composed of:
- struct io_pagetable holding the IOVA map
- struct iopt_areas representing populated portions of IOVA
- struct iopt_pages representing the storage of PFNs
- struct iommu_domain representing each IO page table in the system IOMMU
- struct iopt_pages_access representing in-kernel accesses of PFNs (ie
VFIO mdevs)
- struct xarray pinned_pfns holding a list of pages pinned by in-kernel
accesses
This patch introduces the lowest part of the datastructure - the movement
of PFNs in a tiered storage scheme:
1) iopt_pages::pinned_pfns xarray
2) Multiple iommu_domains
3) The origin of the PFNs, i.e. the userspace pointer
PFN have to be copied between all combinations of tiers, depending on the
configuration.
The interface is an iterator called a 'pfn_reader' which determines which
tier each PFN is stored and loads it into a list of PFNs held in a struct
pfn_batch.
Each step of the iterator will fill up the pfn_batch, then the caller can
use the pfn_batch to send the PFNs to the required destination. Repeating
this loop will read all the PFNs in an IOVA range.
The pfn_reader and pfn_batch also keep track of the pinned page accounting.
While PFNs are always stored and accessed as full PAGE_SIZE units the
iommu_domain tier can store with a sub-page offset/length to support
IOMMUs with a smaller IOPTE size than PAGE_SIZE.
Link: https://lore.kernel.org/r/8-v6-a196d26f289e+11787-iommufd_jgg@nvidia.com
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Tested-by: Nicolin Chen <nicolinc@nvidia.com>
Tested-by: Yi Liu <yi.l.liu@intel.com>
Tested-by: Lixiao Yang <lixiao.yang@intel.com>
Tested-by: Matthew Rosato <mjrosato@linux.ibm.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Diffstat (limited to 'drivers/iommu/iommufd/iommufd_private.h')
-rw-r--r-- | drivers/iommu/iommufd/iommufd_private.h | 24 |
1 files changed, 24 insertions, 0 deletions
diff --git a/drivers/iommu/iommufd/iommufd_private.h b/drivers/iommu/iommufd/iommufd_private.h index bb720bc11317..169a30ff3bf0 100644 --- a/drivers/iommu/iommufd/iommufd_private.h +++ b/drivers/iommu/iommufd/iommufd_private.h @@ -14,6 +14,30 @@ struct iommufd_ctx { struct xarray objects; }; +/* + * The IOVA to PFN map. The map automatically copies the PFNs into multiple + * domains and permits sharing of PFNs between io_pagetable instances. This + * supports both a design where IOAS's are 1:1 with a domain (eg because the + * domain is HW customized), or where the IOAS is 1:N with multiple generic + * domains. The io_pagetable holds an interval tree of iopt_areas which point + * to shared iopt_pages which hold the pfns mapped to the page table. + * + * The locking order is domains_rwsem -> iova_rwsem -> pages::mutex + */ +struct io_pagetable { + struct rw_semaphore domains_rwsem; + struct xarray domains; + unsigned int next_domain_id; + + struct rw_semaphore iova_rwsem; + struct rb_root_cached area_itree; + /* IOVA that cannot become reserved, struct iopt_allowed */ + struct rb_root_cached allowed_itree; + /* IOVA that cannot be allocated, struct iopt_reserved */ + struct rb_root_cached reserved_itree; + u8 disable_large_pages; +}; + struct iommufd_ucmd { struct iommufd_ctx *ictx; void __user *ubuffer; |