Re: [PATCH v3 0/3] virtio DMA API core stuff

From: Benjamin Herrenschmidt
Date: Thu Nov 19 2015 - 21:57:51 EST


On Thu, 2015-11-19 at 23:38 +0000, David Woodhouse wrote:
>
> I understand that POWER and other platforms don't currently have a
> clean way to indicate that certain device don't have translation. And I
> understand that we may end up with a *quirk* which ensures that the DMA
> API does the right thing (i.e. nothing) in certain cases.
>
> But we should *NOT* be involving the virtio device drivers in that
> quirk, in any way. And putting a feature bit in the virtio device
> itself doesn't seem at all sane either.
>
> Bear in mind that qemu-system-x86_64 currently has the *same* problem
> with assigned physical devices. It's claiming they're translated, and
> they're not.

It's not that clear but yeah ... as I mentioned, I can't find a
way to do that quirk that won't break when we want to actually use
the iommu...Â

Ben.

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