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Re: [Xen-devel] [PATCH] Make x86_64 swiotlb code to support dma_ops [2/2

To: "Langsdorf, Mark" <mark.langsdorf@xxxxxxx>, <xen-devel@xxxxxxxxxxxxxxxxxxx>
Subject: Re: [Xen-devel] [PATCH] Make x86_64 swiotlb code to support dma_ops [2/2]
From: Keir Fraser <keir@xxxxxxxxxxxxx>
Date: Wed, 28 Feb 2007 21:43:07 +0000
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On 28/2/07 21:35, "Langsdorf, Mark" <mark.langsdorf@xxxxxxx> wrote:

>> Other points that I can see from a quick browse include the fact that
>> alloc_coherent() still looks broken afaics
> 
> The i386 swiotlb implementation doesn't seem to have an
> alloc_coherent().  Since all this patch is intended to do
> is move swiotlb into the x86_64 directory, I'm not sure
> how to resolve the broken implementation.

By pulling in a new arch/x86_64/pci-dma-xen.c you are replacing the
implementations of things like dma_alloc_coherent(). These replacements,
being pretty much unmodified from the x86/64 native originals, simply aren't
going to work on Xen. I'm not sure how far we'll need to deviate -- I
suspect we'll end up with a file that look much like the i386/pci-dma-xen.c
but with calls to swiotlb_xxx() replaced with dma_ops->xxx. Maybe we could
even stick with just i386/pci-dma-xen.c and macro up the uses of
swiotlb_xxx() (so that they can be replaced with uses of dma_ops->xxx for
x86/64 by cpp).

 -- Keir


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