Re: [Xen-devel] [PATCH] Use lib/swiotlb code for x86_64 SWIOTLB

["Jan Beulich" <jbeulich@xxxxxxxxxx>]

>>> Keir Fraser <Keir.Fraser@xxxxxxxxxxxx> 16.02.07 01:00 >>>
>On 15/2/07 22:59, "Langsdorf, Mark" <mark.langsdorf@xxxxxxx> wrote:
>
>> As part of my efforts to enable GART/IOMMU on x86_64,
>> I switch from using arch/i386/swiotlb-xen.c for the
>> SWIOTLB implementation to lib/swiotlb-xen.c for x86_64
>> processors.
>> 
>> After this patch is accepted, I'll submit the patch to
>> enable the GART/IOMMU.
>> 
>> Signed-off-by: Mark Langsdorf <mark.langsdorf@xxxxxxx>
>
>Jan has been through the swiotlb code recently so may have an opinion on
>this patch. Using the common swiotlb code (as far as possible) for x86/64
>may make sense -- many of the nasty differences in our own swiotlb
>implementation are to deal with CONFIG_HIGHMEM which does not exist on
>x86/64.

I can't see how this can work: First, the way the change is done i386 will also
use that file (and then arch/i386/kernel/swiotlb.c should also be deleted by
the patch). Second, there's nothing Xen specific anymore in that file, not
even the contiguous region creation (the sole difference to plain 2.6.20 is
the use of virt_to_bus/bus_to_virt). I think the first patch should be really
just a move of arch/i386/kernel/swiotlb.c to lib/swiotlb-xen.c, nothing else.

Jan

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel