Re: [PATCH 00 of 14] swiotlb/x86: lay groundwork for xen dom0 use of swiotlb

Ingo Molnar
2008-12-18T21:03:21Z

* Becky Bruce <beckyb@kernel.crashing.org> wrote:

>> Can you be more specific? What architecture is plan to use highmem
>> support in swiotlb?
>
> 32-bit powerpc needs this support - I was actually about to push a
> similar set of patches. We have several processors that support 36 bits
> of physical address space and do not have any iommu capability. The
> rest of the kernel support for those processors is now in place, so
> swiotlb is the last piece of the puzzle for that to be fully functional.
> I need to take a closer look at this series to see exactly what it's
> doing and how it differs from what I've been testing.
>
> So there is another immediate use case, and I'd really hate to see this
> code duplicated. It should be entirely possible to remove the
> assumption that we can save off the VA of the original buffer, which is
> the thing that precludes HIGHMEM support, and still have nice readable,
> maintainable code.

you can have a look at Jeremy's current lineup of patches in
tip/core/iotlb:

http://people.redhat.com/mingo/tip.git/README

(also integrated into tip/master)

What would be needed to make it suit your usecase too?

Ingo