Re: [PATCH] swiotlb-xen: override common mmap and get_sgtable dma ops

[Boris Ostrovsky]

On 6/14/21 8:47 AM, Roman Skakun wrote:
> Hey, Boris!
> Thanks for the review.
>
> I have an additional question about current implementation that disturbed me.
> I think, that we can have cases when mapped memory can not be
> physically contiguous.
> In order to proceed this correctly need to apply some additional steps
> to current implementation as well.
>
> In mmap() :
> 1. Is the memory region physically contiguous?
> 2. Remap multiple ranges if it is not.
>
> In get_sgtable() :
> 1. Is the memory region physically contiguous?
> 2. Create sgt that will be included multiple contiguous ranges if it is not.
>
> What do you think about it?


We make sure that we allocate contiguous memory in xen_swiotlb_alloc_coherent().


-boris