Re: [PATCH v7 13/22] dma: swiotlb: track pool encryption state and honor DMA_ATTR_CC_SHARED

[Jason Gunthorpe]

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 <jiri@xxxxxxxxxx>
> Tested-by: Michael Kelley <mhklinux@xxxxxxxxxxx>
> Tested-by: Mostafa Saleh <smostafa@xxxxxxxxxx>
> Signed-off-by: Aneesh Kumar K.V (Arm) <aneesh.kumar@xxxxxxxxxx>
> ---
>  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@xxxxxxxxxx>

Jason