Re: [RFC PATCH v2 1/5] dma-mapping: Avoid double decrypting with DMA_RESTRICTED_POOL

Aneesh Kumar K.V
2026-04-13T15:25:36Z

Jason Gunthorpe <jgg@ziepe.ca> writes:

> On Mon, Apr 13, 2026 at 11:30:38AM +0530, Aneesh Kumar K.V wrote:
>
>> I know there is a v3, but I’m commenting here to check whether we really
>> need to do this now. In my opinion, we can keep this much simpler by
>> treating all swiotlb allocations as decrypted allocations.
>
> That's not going to work when we get to supporting T=1 devices that
> may still want SWIOTLB for encrypted memory.
>

Earlier discussions indicated that a T=1 device would not require a
bounce buffer. On ARM, we require such devices to support 64-bit DMA so
they can operate with an unprotected IPA.

-aneesh