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

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-direct: pass attrs to dma_capable() for DMA_ATTR_CC_SHARED checks

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

Teach dma_capable() about DMA_ATTR_CC_SHARED so the capability
check can reject encrypted DMA addresses for devices that require
unencrypted/shared DMA.

Also propagate DMA_ATTR_CC_SHARED in swiotlb_map() when the selected
SWIOTLB pool is decrypted so the capability check sees the correct DMA
address attribute.

Reviewed-by: Jason Gunthorpe 
Tested-by: Jiri Pirko 
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/20260717180442.110954-16-aneesh.kumar@kernel.org
Signed-off-by: Marek Szyprowski

dma-mapping: introduce DMA_ATTR_CC_SHARED for shared memory

2026-04-02T05:29:33+00:00

Current CC designs don't place a vIOMMU in front of untrusted devices.
Instead, the DMA API forces all untrusted device DMA through swiotlb
bounce buffers (is_swiotlb_force_bounce()) which copies data into
shared memory on behalf of the device.

When a caller has already arranged for the memory to be shared
via set_memory_decrypted(), the DMA API needs to know so it can map
directly using the unencrypted physical address rather than bounce
buffering. Following the pattern of DMA_ATTR_MMIO, add
DMA_ATTR_CC_SHARED for this purpose. Like the MMIO case, only the
caller knows what kind of memory it has and must inform the DMA API
for it to work correctly.

Signed-off-by: Jiri Pirko 
Reviewed-by: Jason Gunthorpe 
Acked-by: Sumit Semwal 
Signed-off-by: Marek Szyprowski 
Link: https://lore.kernel.org/r/20260325192352.437608-2-jiri@resnulli.us

Merge tag 'dma-mapping-7.0-2026-03-25' into dma-mapping-for-next

2026-03-25T17:25:43+00:00

dma-mapping fixes for Linux 7.0

A set of fixes for DMA-mapping subsystem, which resolve false-positive
warnings from KMSAN and DMA-API debug (Shigeru Yoshida and Leon
Romanovsky) as well as a simple build fix (Miguel Ojeda).

Signed-off-by: Marek Szyprowski

dma-direct: prevent SWIOTLB path when DMA_ATTR_REQUIRE_COHERENT is set

2026-03-20T11:05:56+00:00

DMA_ATTR_REQUIRE_COHERENT indicates that SWIOTLB must not be used.
Ensure the SWIOTLB path is declined whenever the DMA direct path is
selected.

Signed-off-by: Leon Romanovsky 
Signed-off-by: Marek Szyprowski 
Link: https://lore.kernel.org/r/20260316-dma-debug-overlap-v3-5-1dde90a7f08b@nvidia.com

dma-mapping: Support batch mode for dma_direct_{map,unmap}_sg

2026-03-13T22:47:48+00:00

Extending these APIs with a flush argument:
dma_direct_unmap_phys(), dma_direct_map_phys(), and
dma_direct_sync_single_for_cpu(). For single-buffer cases, flush=true
would be used, while for SG cases flush=false would be used, followed
by a single flush after all cache operations are issued in
dma_direct_{map,unmap}_sg().

This ultimately benefits dma_map_sg() and dma_unmap_sg().

Cc: Catalin Marinas 
Cc: Will Deacon 
Cc: Marek Szyprowski 
Cc: Robin Murphy 
Cc: Ada Couprie Diaz 
Cc: Ard Biesheuvel 
Cc: Marc Zyngier 
Cc: Anshuman Khandual 
Cc: Ryan Roberts 
Cc: Suren Baghdasaryan 
Cc: Tangquan Zheng 
Reviewed-by: Leon Romanovsky 
Tested-by: Xueyuan Chen 
Signed-off-by: Barry Song 
Signed-off-by: Marek Szyprowski 
Link: https://lore.kernel.org/r/20260228221337.59951-1-21cnbao@gmail.com

dma-mapping: Separate DMA sync issuing and completion waiting

2026-03-13T22:47:31+00:00

Currently, arch_sync_dma_for_cpu and arch_sync_dma_for_device
always wait for the completion of each DMA buffer. That is,
issuing the DMA sync and waiting for completion is done in a
single API call.

For scatter-gather lists with multiple entries, this means
issuing and waiting is repeated for each entry, which can hurt
performance. Architectures like ARM64 may be able to issue all
DMA sync operations for all entries first and then wait for
completion together.

To address this, arch_sync_dma_for_* now batches DMA operations
and performs a flush afterward. On ARM64, the flush is implemented
with a dsb instruction in arch_sync_dma_flush(). On other
architectures, arch_sync_dma_flush() is currently a nop.

Cc: Leon Romanovsky 
Cc: Catalin Marinas 
Cc: Will Deacon 
Cc: Marek Szyprowski 
Cc: Robin Murphy 
Cc: Ada Couprie Diaz 
Cc: Ard Biesheuvel 
Cc: Marc Zyngier 
Cc: Anshuman Khandual 
Cc: Ryan Roberts 
Cc: Suren Baghdasaryan 
Cc: Joerg Roedel 
Cc: Stefano Stabellini 
Cc: Oleksandr Tyshchenko 
Cc: Tangquan Zheng 
Reviewed-by: Juergen Gross  # drivers/xen/swiotlb-xen.c
Tested-by: Xueyuan Chen 
Signed-off-by: Barry Song 
Reviewed-by: Leon Romanovsky 
Signed-off-by: Marek Szyprowski 
Link: https://lore.kernel.org/r/20260228221316.59934-1-21cnbao@gmail.com

dma-mapping: avoid random addr value print out on error path

2026-02-23T07:26:54+00:00

dma_addr is unitialized in dma_direct_map_phys() when swiotlb is forced
and DMA_ATTR_MMIO is set which leads to random value print out in
warning. Fix that by just returning DMA_MAPPING_ERROR.

Fixes: e53d29f957b3 ("dma-mapping: convert dma_direct_*map_page to be phys_addr_t based")
Signed-off-by: Jiri Pirko 
Signed-off-by: Marek Szyprowski 
Link: https://lore.kernel.org/r/20260209153809.250835-2-jiri@resnulli.us

dma-mapping: Remove dma_mark_clean (again)

2026-01-07T23:19:08+00:00

With IA-64 now gone, there are no users of the dma_mark_clean hook,
so we can retire it for good.

Signed-off-by: Robin Murphy 
Signed-off-by: Marek Szyprowski 
Link: https://lore.kernel.org/r/c004927f01962726ff1dcf94d1b4efff84db805a.1767727673.git.robin.murphy@arm.com

dma-mapping: convert dma_direct_*map_page to be phys_addr_t based

2025-09-11T22:18:20+00:00

Convert the DMA direct mapping functions to accept physical addresses
directly instead of page+offset parameters. The functions were already
operating on physical addresses internally, so this change eliminates
the redundant page-to-physical conversion at the API boundary.

The functions dma_direct_map_page() and dma_direct_unmap_page() are
renamed to dma_direct_map_phys() and dma_direct_unmap_phys() respectively,
with their calling convention changed from (struct page *page,
unsigned long offset) to (phys_addr_t phys).

Architecture-specific functions arch_dma_map_page_direct() and
arch_dma_unmap_page_direct() are similarly renamed to
arch_dma_map_phys_direct() and arch_dma_unmap_phys_direct().

The is_pci_p2pdma_page() checks are replaced with DMA_ATTR_MMIO checks
to allow integration with dma_direct_map_resource and dma_direct_map_phys()
is extended to support MMIO path either.

Reviewed-by: Jason Gunthorpe 
Signed-off-by: Leon Romanovsky 
Signed-off-by: Marek Szyprowski 
Link: https://lore.kernel.org/r/bb15a22f76dc2e26683333ff54e789606cfbfcf0.1757423202.git.leonro@nvidia.com