Re: [PATCH v1 2/2] dma-mapping-common: add DMA attribute - DMA_ATTR_IOMMU_BYPASS

David Woodhouse
2015-10-28T06:30:01Z

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On Sun, 2015-10-25 at 09:07 -0700, Shamir Rabinovitch wrote:
>
> +
> +DMA_ATTR_IOMMU_BYPASS
> +---------------------
> +
> > +For systems with IOMMU it is assumed all DMA translations use the IOMMU.

Not entirely true. We have per-device dma_ops on a most architectures
already, and we were just talking about the need to add them to
POWER/SPARC too, because we need to avoid trying to use the IOMMU to
map virtio devices too.

As we look at that (and make the per-device dma_ops a generic thing
rather than per-arch), we should probably look at folding your case in
too.

--
dwmw2

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