linux.git/kernel/dma/direct.c, branch v7.3-rc2

Merge tags 'dma-mapping-7.3-2026-08-24' and 'dma-mapping-7.3-2026-08-24-2' of git://git.kernel.org/pub/scm/linux/kernel/git/mszyprowski/linux

2026-08-24T18:35:46+00:00

Pull dma-mapping updates from Marek Szyprowski:

 - swiotlb:
     - new configuration option for the default pool size
       (Jagadeesh Pagadala)
     - reduce overhead for high watermark tracking (chenhuguanshen)

 - minor code cleanups and improvements (Vova Sharaienko, Honglei Huang
   and Marek Szyprowski)

 - add proper tracking of the shared DMA state through direct, pool and
   swiotlb paths (Aneesh Kumar K.V)

   This is important for confidential-computing

* tag 'dma-mapping-7.3-2026-08-24' of git://git.kernel.org/pub/scm/linux/kernel/git/mszyprowski/linux:
  dma/swiotlb: decouple high watermark tracking from CONFIG_DEBUG_FS
  MAINTAINERS: update tree for DMA MAPPING HELPERS
  dma/swiotlb: introduce Kconfig option for compile-time default pool size
  dma-direct: Improve readability of the dma_direct_map_sg() for P2PDMA case
  iommu/dma: simplify dma_iova_destroy() and drop the free_iova helper
  dma-coherent: use KiB in DMA allocation logs
  dma-coherent: fix spacing coding style issue

* tag 'dma-mapping-7.3-2026-08-24-2' of git://git.kernel.org/pub/scm/linux/kernel/git/mszyprowski/linux: (23 commits)
  swiotlb: remove unused SWIOTLB_FORCE flag
  dma: swiotlb: handle set_memory_decrypted() failures
  dma: swiotlb: free dynamic pools from process context
  dma-direct: rename ret to cpu_addr in alloc helpers
  dma-direct: select DMA address encoding from __DMA_ATTR_ALLOC_CC_SHARED
  dma-direct: set decrypted flag for remapped DMA allocations
  dma-direct: make dma_direct_map_phys() honor DMA_ATTR_CC_SHARED
  dma-direct: Move dma_direct_map_phys() to dma/direct.c
  dma-direct: pass attrs to dma_capable() for DMA_ATTR_CC_SHARED checks
  dma-mapping: make dma_pgprot() honor __DMA_ATTR_ALLOC_CC_SHARED
  dma: swiotlb: track pool encryption state and honor DMA_ATTR_CC_SHARED
  dma: swiotlb: pass mapping attributes by reference
  dma-pool: track decrypted atomic pools and select them via attrs
  dma-direct: use __DMA_ATTR_ALLOC_CC_SHARED in alloc/free paths
  dma-mapping: Add internal shared allocation attribute
  coco: arm64: s390: powerpc: Mark secure guests with CC_ATTR_GUEST_MEM_ENCRYPT
  dma-direct: swiotlb: handle swiotlb alloc/free outside __dma_direct_alloc_pages
  s390: Expose protected virtualization through cc_platform_has()
  swiotlb: Preserve allocation virtual address for dynamic pools
  dma: free atomic pool pages by physical address
  ...

mm: prefer vma_[start,end]_pgoff() to vma->vm_pgoff in kernel/

2026-08-05T02:19:01+00:00

Be consistent in using vma_start_pgoff() and vma_end_pgoff(), which clearly
indicates which part of the VMA the page offset refers to and aids
greppability.

This is part of a broader series laying the ground to provide a virtual
page offset for MAP_PRIVATE-file backed anon folios.

No functional change intended.

Link: https://lore.kernel.org/20260710-b4-pre-scalable-cow-v2-19-2a5aa403d977@kernel.org
Signed-off-by: Lorenzo Stoakes 
Acked-by: Marek Szyprowski  # for kernel/dma
Reviewed-by: Gregory Price 
Acked-by: Pedro Falcato 
Reviewed-by: Vlastimil Babka (SUSE) 
Cc: Ackerley Tng 
Cc: David Hildenbrand (Arm) 
Cc: Kai Huang 
Cc: SJ Park 
Cc: Thomas Zimmermann 
Cc: Liam R. Howlett (Oracle) 
Cc: Zi Yan 
Signed-off-by: Andrew Morton

dma-direct: rename ret to cpu_addr in alloc helpers

2026-07-31T06:44:52+00:00

ret in dma_direct_alloc() and dma_direct_alloc_pages() holds the returned
CPU mapping, not a generic return value. Rename it to cpu_addr and update
the remaining uses to match.

This makes the allocation paths easier to follow and keeps the local naming
consistent with what the variable actually represents.

Reviewed-by: Jason Gunthorpe 
Tested-by: Michael Kelley 
Tested-by: Mostafa Saleh 
Reviewed-by: Petr Tesarik 
Signed-off-by: Aneesh Kumar K.V (Arm) 
Link: https://lore.kernel.org/r/20260717180442.110954-21-aneesh.kumar@kernel.org
Signed-off-by: Marek Szyprowski

dma-direct: select DMA address encoding from __DMA_ATTR_ALLOC_CC_SHARED

2026-07-31T06:44:52+00:00

Make the dma-direct helpers derive the DMA address encoding from
__DMA_ATTR_ALLOC_CC_SHARED instead of implicitly relying on
force_dma_unencrypted() inside phys_to_dma_direct()

Pass an explicit unencrypted/decrypted state into phys_to_dma_direct(),
make the alloc paths return DMA addresses that match the requested buffer
encryption state. Also only call dma_set_decrypted() when
__DMA_ATTR_ALLOC_CC_SHARED is actually set.

Reviewed-by: Jason Gunthorpe 
Tested-by: Jiri Pirko 
Tested-by: Michael Kelley 
Tested-by: Mostafa Saleh 
Signed-off-by: Aneesh Kumar K.V (Arm) 
Reviewed-by: Mostafa Saleh 
Link: https://lore.kernel.org/r/20260717180442.110954-20-aneesh.kumar@kernel.org
Signed-off-by: Marek Szyprowski

dma-direct: set decrypted flag for remapped DMA allocations

2026-07-31T06:44:52+00:00

Devices that are DMA non-coherent and require a remap were skipping
dma_set_decrypted(), leaving DMA buffers encrypted even when the device
requires unencrypted access. Move the call after the if (remap) branch
so that both the direct and remapped allocation paths correctly mark the
allocation as decrypted (or fail cleanly) before use.

Fix dma_direct_alloc() and dma_direct_free() to apply set_memory_*() to the
linear-map alias of the backing pages instead of the remapped CPU address.
Also disallow highmem pages for __DMA_ATTR_ALLOC_CC_SHARED, because highmem
buffers do not provide a usable linear-map address.

Reviewed-by: Jason Gunthorpe 
Tested-by: Jiri Pirko 
Tested-by: Michael Kelley 
Tested-by: Mostafa Saleh 
Signed-off-by: Aneesh Kumar K.V (Arm) 
Link: https://lore.kernel.org/r/20260717180442.110954-19-aneesh.kumar@kernel.org
Signed-off-by: Marek Szyprowski

dma-direct: make dma_direct_map_phys() honor DMA_ATTR_CC_SHARED

2026-07-31T06:44:03+00:00

Teach dma_direct_map_phys() to select the DMA address encoding based on
DMA_ATTR_CC_SHARED.

Use phys_to_dma_unencrypted() for decrypted mappings and
phys_to_dma_encrypted() otherwise. If a device requires unencrypted DMA
but the source physical address is still encrypted, force the mapping
through swiotlb so the DMA address and backing memory attributes remain
consistent.

Update the arm64, x86, s390 and powerpc secure-guest setup to not use
swiotlb force option

Tested-by: Jiri Pirko 
Tested-by: Michael Kelley 
Tested-by: Mostafa Saleh 
Signed-off-by: Aneesh Kumar K.V (Arm) 
Link: https://lore.kernel.org/r/20260717180442.110954-18-aneesh.kumar@kernel.org
[mszyprow: rebased onto latest changes in arch/arm64/mm/init.c]
Signed-off-by: Marek Szyprowski

dma-direct: Move dma_direct_map_phys() to dma/direct.c

2026-07-31T06:40:59+00:00

dma_direct_map_phys() is too large to benefit from being inlined. Move its
implementation to direct.c and leave the declaration in direct.h.

No functional change in this patch

Signed-off-by: Aneesh Kumar K.V (Arm) 
Link: https://lore.kernel.org/r/20260717180442.110954-17-aneesh.kumar@kernel.org
Signed-off-by: Marek Szyprowski

dma-mapping: make dma_pgprot() honor __DMA_ATTR_ALLOC_CC_SHARED

2026-07-31T06:40:59+00:00

Fold encrypted/decrypted pgprot selection into dma_pgprot() so callers
do not need to adjust the page protection separately.

Update dma_pgprot() to apply pgprot_decrypted() when DMA_ATTR_CC_SHARED or
__DMA_ATTR_ALLOC_CC_SHARED is set and pgprot_encrypted() otherwise Convert
the dma-direct mmap paths to pass DMA_ATTR_CC_SHARED instead of open-coding
force_dma_unencrypted() handling around dma_pgprot().

Reviewed-by: Jason Gunthorpe 
Tested-by: Jiri Pirko 
Tested-by: Michael Kelley 
Tested-by: Mostafa Saleh 
Signed-off-by: Aneesh Kumar K.V (Arm) 
Link: https://lore.kernel.org/r/20260717180442.110954-15-aneesh.kumar@kernel.org
Signed-off-by: Marek Szyprowski

dma: swiotlb: track pool encryption state and honor DMA_ATTR_CC_SHARED

2026-07-31T06:40:59+00:00

Teach swiotlb to distinguish between encrypted and decrypted bounce
buffer pools, and make allocation and mapping paths select a pool whose
state matches the requested DMA attributes.

Add a cc_shared flag to io_tlb_mem, initialize it for the default and
restricted pools, and propagate __DMA_ATTR_ALLOC_CC_SHARED into swiotlb
pool allocation. Reject swiotlb alloc/map requests when the selected pool
does not match the required encrypted/decrypted state.

Also return DMA addresses with the matching phys_to_dma_{encrypted,
unencrypted} helper so the DMA address encoding stays consistent with the
chosen pool.

Reviewed-by: Jason Gunthorpe 
Tested-by: Jiri Pirko 
Tested-by: Michael Kelley 
Tested-by: Mostafa Saleh 
Signed-off-by: Aneesh Kumar K.V (Arm) 
Link: https://lore.kernel.org/r/20260717180442.110954-14-aneesh.kumar@kernel.org
Signed-off-by: Marek Szyprowski

dma-pool: track decrypted atomic pools and select them via attrs

2026-07-31T06:40:58+00:00

Teach the atomic DMA pool code to distinguish between encrypted and
unencrypted pools, and make pool allocation select the matching pool based
on DMA attributes.

Introduce a dma_gen_pool wrapper that records whether a pool is
unencrypted, initialize that state when the atomic pools are created, and
use it when expanding and resizing the pools. Update dma_alloc_from_pool()
to take attrs and skip pools whose encrypted state does not match
__DMA_ATTR_ALLOC_CC_SHARED. Update dma_free_from_pool() accordingly.

Also pass __DMA_ATTR_ALLOC_CC_SHARED from the swiotlb atomic allocation
path so decrypted swiotlb allocations are taken from the correct atomic
pool.

Tested-by: Jiri Pirko 
Tested-by: Michael Kelley 
Tested-by: Mostafa Saleh 
Reviewed-by: Mostafa Saleh 
Signed-off-by: Aneesh Kumar K.V (Arm) 
Link: https://lore.kernel.org/r/20260717180442.110954-12-aneesh.kumar@kernel.org
Signed-off-by: Marek Szyprowski