Re: [PATCH 1/3] crypto: ccp - Add function to allocate and free memory using DMA APIs

Hi Christoph,

On 30-Oct-23 7:03 PM, Christoph Hellwig wrote:

On Fri, Oct 27, 2023 at 07:05:17PM +0530, NK, JESHWANTHKUMAR wrote:

...

Can you please elaborate a bit more?

Becasue the DMA API is a blackbox. You can pass the dma_addr_t to hardware, and you can use the kernel virtual address. That it can sometimes be implemented using the IMMU API is an implementation detail. Similarly you can only feeds iovas generated by the IOMMU API into the IOMMU API, not any random other scalar value, which is what you can get from the DMA API.

Thanks for the explanation, I will send a new version of the patch.

Regards,

Jeshwanth