[PATCH v7 17/22] dma-direct: set decrypted flag for remapped DMA allocations

[Jason Gunthorpe]

On Wed, Jul 01, 2026 at 11:19:21AM +0530, Aneesh Kumar K.V (Arm) wrote:
> 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.
> 
> Tested-by: Jiri Pirko <jiri at nvidia.com>
> Tested-by: Michael Kelley <mhklinux at outlook.com>
> Tested-by: Mostafa Saleh <smostafa at google.com>
> Signed-off-by: Aneesh Kumar K.V (Arm) <aneesh.kumar at kernel.org>
> ---
>  kernel/dma/direct.c | 56 +++++++++++++++++++++++++++++++++++----------
>  1 file changed, 44 insertions(+), 12 deletions(-)

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

Jason