Hello Jiri,

On Tue, 7 Apr 2026 at 14:56, Jiri Pirko jiri@resnulli.us wrote:

From: Jiri Pirko jiri@nvidia.com

Document the system_cc_shared dma-buf heap that was introduced recently. Describe its purpose, availability conditions and relation to confidential computing VMs.

Signed-off-by: Jiri Pirko jiri@nvidia.com Reviewed-by: T.J.Mercier tjmercier@google.com

Thank you for the patch!

Marek: Since you're taking the dependent patches through your tree, could you please use: Acked-by: Sumit Semwal sumit.semwal@linaro.org

and take this as well?

Thanks and Best regards, Sumit.

---

Documentation/userspace-api/dma-buf-heaps.rst | 7 +++++++ 1 file changed, 7 insertions(+)

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

-- 2.51.1