On Wed, Jul 01, 2026 at 11:19:17AM +0530, Aneesh Kumar K.V (Arm) wrote:

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.

Tested-by: Jiri Pirko <redacted>
Tested-by: Michael Kelley <redacted>
Tested-by: Mostafa Saleh <smostafa@google.com>
Signed-off-by: Aneesh Kumar K.V (Arm) <aneesh.kumar@kernel.org>
---
 include/linux/dma-direct.h |  10 +++
 include/linux/swiotlb.h    |  10 ++-
 kernel/dma/direct.c        |  13 ++-
 kernel/dma/swiotlb.c       | 177 ++++++++++++++++++++++++++++---------
 4 files changed, 162 insertions(+), 48 deletions(-)

Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>

Jason