On Tue, May 19, 2026 at 09:35:30PM +0530, Aneesh Kumar K.V wrote:
> Yes, that also resulted in simpler and cleaner code.
>
> swiotlb_tbl_map_single
> /*
> * If the physical address is encrypted but the device requires
> * decrypted DMA, use a decrypted io_tlb_mem and update the
> * attributes so the caller knows that a decrypted io_tlb_mem
> * was used.
> */
> if (!(*attrs & DMA_ATTR_CC_SHARED) && force_dma_unencrypted(dev))
> *attrs |= DMA_ATTR_CC_SHARED;
>
> if (mem->unencrypted != !!(*attrs & DMA_ATTR_CC_SHARED))
> return (phys_addr_t)DMA_MAPPING_ERROR;
Yeah, exactly that is so much clearer now that the mem->unecrypted is
tied directly.
That logic is reversed though, the incoming ATTR_CC doesn't matter for
swiotlb, that is just the source of the memcpy.
/* swiotlb pool is incorrect for this device */
if (mem->unencrypted != force_dma_unencrypted(dev))
return (phys_addr_t)DMA_MAPPING_ERROR;
/* Force attrs to match the kind of memory in the pool */
if (mem->unencrypted)
*attrs |= DMA_ATTR_CC_SHARED;
else
*attrs &= ~DMA_ATTR_CC_SHARED;
Attrs should be forced to whatever memory swiotlb selected.
Jason
