Messages in this thread | | | Date | Wed, 2 Jul 2003 19:20:26 +0200 | From | Andi Kleen <> | Subject | Re: [RFC] block layer support for DMA IOMMU bypass mode II |
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On Wed, Jul 02, 2003 at 10:55:10AM -0600, Grant Grundler wrote: > On Wed, Jul 02, 2003 at 01:57:01AM +0200, Andi Kleen wrote: > > The K8 IOMMU cannot support this virtually contiguous thing. The reason > > is that there is no guarantee that an entry in a sglist is a multiple > > of page size. And the aperture can only map 4K sized chunks, like > > a CPU MMU. So e.g. when you have an sglist with multiple 1K entries there is > > no way to get them continuous in IOMMU space (short of copying) > > Can two adjacent IOMMU entries be used to map two 1K buffers? > Assume the 1st buffer ends on a 4k alignment and the next one > starts on a 4k alignment.
Yes, it could. But is that situation likely/worth to handle?
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