Messages in this thread | | | Date | Sun, 28 Sep 2008 20:49:26 +0200 | From | Joerg Roedel <> | Subject | Re: [PATCH 0/9][RFC] stackable dma_ops for x86 |
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On Sun, Sep 28, 2008 at 11:21:26PM +0900, FUJITA Tomonori wrote: > On Mon, 22 Sep 2008 20:21:12 +0200 > Joerg Roedel <joerg.roedel@amd.com> wrote: > > > Hi, > > > > this patch series implements stackable dma_ops on x86. This is useful to > > be able to fall back to a different dma_ops implementation if one can > > not handle a particular device (as necessary for example with > > paravirtualized device passthrough or if a hardware IOMMU only handles a > > subset of available devices). > > We already handle the latter. This patchset is more flexible but > seems to incur more overheads. > > This feature will be used for only paravirtualized device passthrough? > If so, I feel that there is more simpler (and specific) solutions for > it.
Its not only for device passthrough. It handles also the cases where a hardware IOMMU does not handle all devices in the system (like in some Calgary systems but also possible with AMD IOMMU). With this patchset we can handle these cases in a generic way without hacking it into the hardware drivers (these hacks are also in the AMD IOMMU code and I plan to remove them in the case this patchset will be accepted).
Joerg
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