On Mon, Aug 16, 2021 at 10:50:26PM +0800, Tianyu Lan wrote:

Hi Christoph:
      Sorry to bother you.Please double check with these two patches
" [PATCH V3 10/13] x86/Swiotlb: Add Swiotlb bounce buffer remap function 
for HV IVM" and "[PATCH V3 09/13] DMA: Add dma_map_decrypted/dma_
unmap_encrypted() function".

Do you have a git tree somewhere to look at the whole tree?

      The swiotlb bounce buffer in the isolation VM are allocated in the
low end memory and these memory has struct page backing. All dma address
returned by swiotlb/DMA API are low end memory and this is as same as what 
happen in the traditional VM.

Indeed.

      The API dma_map_decrypted() introduced in the patch 9 is to map the 
bounce buffer in the extra space and these memory in the low end space are 
used as DMA memory in the driver. Do you prefer these APIs
still in the set_memory.c? I move the API to dma/mapping.c due to the
suggested name arch_dma_map_decrypted() in the previous mail
(https://lore.kernel.org/netdev/20210720135437.GA13554@lst.de/ (local)).

Well, what would help is a clear description of the semantics.