On Wed, Jul 01, 2026 at 11:19:13AM +0530, Aneesh Kumar K.V (Arm) wrote: > DMA_ATTR_CC_SHARED describes an existing DMA mapping whose backing memory > is already shared, or decrypted, for confidential computing. It is a > mapping attribute: callers use it to request a shared DMA address encoding > for memory that has already been prepared for shared DMA. > > Allocation paths need a related but different state. Once the DMA core > decides that an allocation must use shared backing pages, the lower-level > allocation helpers need to select shared pools, decrypt newly allocated > pages, derive the DMA address with the shared-memory translation and > restore encryption on free. That state is internal to the DMA-mapping > implementation and should not be passed by drivers to dma_alloc_attrs(). > > Signed-off-by: Aneesh Kumar K.V (Arm) <[email protected]> > --- > Documentation/core-api/dma-attributes.rst | 29 +++++++++++++++++++++++ > include/linux/dma-mapping.h | 8 +++++++ > include/trace/events/dma.h | 3 ++- > 3 files changed, 39 insertions(+), 1 deletion(-)
Reviewed-by: Jason Gunthorpe <[email protected]> Jason
