netdev - Re: [Resend RFC PATCH V4 09/13] x86/Swiotlb/HV: Add Swiotlb bounce buffer remap function for HV IVM

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Date:   Sat, 14 Aug 2021 00:43:16 +0800
From:   Tianyu Lan <ltykernel@...il.com>
To:     Christoph Hellwig <hch@....de>
Cc:     kys@...rosoft.com, haiyangz@...rosoft.com, sthemmin@...rosoft.com,
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Subject: Re: [Resend RFC PATCH V4 09/13] x86/Swiotlb/HV: Add Swiotlb bounce
 buffer remap function for HV IVM

Hi Christoph:
       I followed your this suggestion to rework the latest
version(https://lkml.org/lkml/2021/8/9/805). I just remove the arch
prefix from your suggested name arch_dma_map_decrypted because the 
platform may populate their map/umap callback in the ops. But from your 
latest comment(https://lkml.org/lkml/2021/8/12/149), these names confuse 
vs the actual dma_map_* calls... Could you help to give the right 
function name? The new map function is to map bounce buffer in the 
trust/Isolation VM and these buffers are DMA memory.



On 7/20/2021 9:54 PM, Christoph Hellwig wrote:
>> -	set_memory_decrypted((unsigned long)vaddr, bytes >> PAGE_SHIFT);
>> -	memset(vaddr, 0, bytes);
>> +	mem->vstart = (void *)set_memory_decrypted_map((unsigned long)vaddr, bytes);
> Please always pass kernel virtual addresses as pointers.
> 
> And I think these APIs might need better names, e.g.
> 
> arch_dma_map_decrypted and arch_dma_unmap_decrypted.
> 
> Also these will need fallback versions for non-x86 architectures that
> currently use memory encryption.