Re: [Xen-devel] [PATCH 07/11] swiotlb-xen: provide a single page-coherent.h header

[Julien Grall]

Hi,

On 8/16/19 2:00 PM, Christoph Hellwig wrote:
> Merge the various page-coherent.h files into a single one that either
> provides prototypes or stubs depending on the need for cache
> maintainance.
>
> For extra benefits alo include <xen/page-coherent.h> in the file
> actually implementing the interfaces provided.
>
> Signed-off-by: Christoph Hellwig <hch@xxxxxx>
> ---
>   arch/arm/include/asm/xen/page-coherent.h   |  2 --
>   arch/arm/xen/mm.c                          |  1 +
>   arch/arm64/include/asm/xen/page-coherent.h |  2 --
>   arch/x86/include/asm/xen/page-coherent.h   | 22 ------------------
>   drivers/xen/swiotlb-xen.c                  |  4 +---
>   include/Kbuild                             |  2 +-
>   include/xen/{arm => }/page-coherent.h      | 27 +++++++++++++++++++---

I am not sure I agree with this rename. The implementation of the 
helpers are very Arm specific as this is assuming Dom0 is 1:1 mapped.

This was necessary due to the lack of IOMMU on Arm platforms back then.
But this is now a pain to get rid of it on newer platform...

Cheers,

--
Julien Grall