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authorLinus Torvalds <torvalds@linux-foundation.org>2026-04-17 11:12:42 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2026-04-17 11:12:42 -0700
commit87768582a440e7049a04e8af7383b86738d15b38 (patch)
treec6490ceb75f0af1ff214b64067fcd29d596f3a53 /Documentation/userspace-api
parentd662a710c668a86a39ebaad334d9960a0cc776c2 (diff)
parent15818b2cd42df3cc886f4cc46acfab4d072dcacc (diff)
Merge tag 'dma-mapping-7.1-2026-04-16' of git://git.kernel.org/pub/scm/linux/kernel/git/mszyprowski/linux
Pull dma-mapping updates from Marek Szyprowski: - added support for batched cache sync, what improves performance of dma_map/unmap_sg() operations on ARM64 architecture (Barry Song) - introduced DMA_ATTR_CC_SHARED attribute for explicitly shared memory used in confidential computing (Jiri Pirko) - refactored spaghetti-like code in drivers/of/of_reserved_mem.c and its clients (Marek Szyprowski, shared branch with device-tree updates to avoid merge conflicts) - prepared Contiguous Memory Allocator related code for making dma-buf drivers modularized (Maxime Ripard) - added support for benchmarking dma_map_sg() calls to tools/dma utility (Qinxin Xia) * tag 'dma-mapping-7.1-2026-04-16' of git://git.kernel.org/pub/scm/linux/kernel/git/mszyprowski/linux: (24 commits) dma-buf: heaps: system: document system_cc_shared heap dma-buf: heaps: system: add system_cc_shared heap for explicitly shared memory dma-mapping: introduce DMA_ATTR_CC_SHARED for shared memory mm: cma: Export cma_alloc(), cma_release() and cma_get_name() dma: contiguous: Export dev_get_cma_area() dma: contiguous: Make dma_contiguous_default_area static dma: contiguous: Make dev_get_cma_area() a proper function dma: contiguous: Turn heap registration logic around of: reserved_mem: rework fdt_init_reserved_mem_node() of: reserved_mem: clarify fdt_scan_reserved_mem*() functions of: reserved_mem: rearrange code a bit of: reserved_mem: replace CMA quirks by generic methods of: reserved_mem: switch to ops based OF_DECLARE() of: reserved_mem: use -ENODEV instead of -ENOENT of: reserved_mem: remove fdt node from the structure dma-mapping: fix false kernel-doc comment marker dma-mapping: Support batch mode for dma_direct_{map,unmap}_sg dma-mapping: Separate DMA sync issuing and completion waiting arm64: Provide dcache_inval_poc_nosync helper arm64: Provide dcache_clean_poc_nosync helper ...
Diffstat (limited to 'Documentation/userspace-api')
-rw-r--r--Documentation/userspace-api/dma-buf-heaps.rst7
1 files changed, 7 insertions, 0 deletions
diff --git a/Documentation/userspace-api/dma-buf-heaps.rst b/Documentation/userspace-api/dma-buf-heaps.rst
index 05445c83b79a..f56b743cdb36 100644
--- a/Documentation/userspace-api/dma-buf-heaps.rst
+++ b/Documentation/userspace-api/dma-buf-heaps.rst
@@ -16,6 +16,13 @@ following heaps:
- The ``system`` heap allocates virtually contiguous, cacheable, buffers.
+ - The ``system_cc_shared`` heap allocates virtually contiguous, cacheable,
+ buffers using shared (decrypted) memory. It is only present on
+ confidential computing (CoCo) VMs where memory encryption is active
+ (e.g., AMD SEV, Intel TDX). The allocated pages have the encryption
+ bit cleared, making them accessible for device DMA without TDISP
+ support. On non-CoCo VM configurations, this heap is not registered.
+
- The ``default_cma_region`` heap allocates physically contiguous,
cacheable, buffers. Only present if a CMA region is present. Such a
region is usually created either through the kernel commandline