Messages in this thread | | | Date | Fri, 16 May 2008 00:39:46 +0300 | From | Muli Ben-Yehuda <> | Subject | Re: [PATCH 0/2] x86: per-device dma_mapping_ops |
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On Thu, May 15, 2008 at 11:03:40PM +0200, Andi Kleen wrote: > On Thu, May 15, 2008 at 06:26:31PM +0300, Muli Ben-Yehuda wrote: > > On Thu, May 15, 2008 at 06:41:26PM +0900, FUJITA Tomonori wrote: > > > > > 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. > > > > That's my understanding too. We use stackable ops as a poor man's > > replacement for per-device ops (depending on what kind of device > > it is, call the original ops or our pvdma ops). > > But in the KVM case you still need to support the underlying ops > too, e.g. in case of bouncing through swiotlb needed
Good point, although "secondary" DMA-ops should only be needed in rare cases (the only one I can think of is bouncing through swiotlb for a pass-through device which has a limited DMA mask), whereas per-device ops are needed for every pass-through device.
Cheers, Muli
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