Messages in this thread | | | Date | Thu, 15 May 2008 18:41:26 +0900 | Subject | Re: [PATCH 0/2] x86: per-device dma_mapping_ops | From | FUJITA Tomonori <> |
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On Thu, 15 May 2008 11:30:12 +0200 Andi Kleen <andi@firstfloor.org> wrote:
> FUJITA Tomonori wrote: > > On Thu, 15 May 2008 11:01:09 +0200 > > Andi Kleen <andi@firstfloor.org> wrote: > > > >> FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> writes: > >> > >>> This patchset adds per-device dma_mapping_ops support for > >>> CONFIG_X86_64 like POWER architecture does. This change enables us to > >>> cleanly fix the Calgary IOMMU issue that some devices are not behind > >>> the IOMMU [1]. It also would be helpful to handle KVM PCI passthrough. > >> This makes it basically impossible to do stack ops, which some > >> people have been doing. > > > > Seems that I misunderstand what those people want. > > > > What those people want to do and how the stack ops achieve it? Or can > > you tell me where their patches are? > > I've seen it in two cases: first was for KVM IO bypass and the other was a > (unfinished) patch to support the NoDMA bitmaps on some systems. > > In this case you really want to do a wrapper around the existing ops > and extend the mapping. > > That worked fine by just replacing the global pointer, but will > be quite hard in your set up.
Thanks,
I thought that KVM people want to do it per device (in the first case). So with my patchse, they can replace the dma_ops pointer in dev_archdata with what they want.
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