Re: [PATCH] intel-iommu: Obey coherent_dma_mask for alloc_coherenton passthrough

From: David Woodhouse
Date: Mon Nov 09 2009 - 20:01:55 EST


On Tue, 2009-11-10 at 00:46 +0000, David Woodhouse wrote:
>
> if (iommu_no_mapping(hwdev))
> - return paddr;
> + return paddr > dma_mask - size ? 0 : paddr;

Hm, that's still wrong. If your mask is 0xffffffff and you map
0xfffff000 + 0x1000, that should be allowed, right? How about:

return paddr <= dma_mask - size + 1 ? paddr : 0;

And is this strictly necessary as part of the patch we're discussing?

--
David Woodhouse Open Source Technology Centre
David.Woodhouse@xxxxxxxxx Intel Corporation

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