[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] Is there a way to map pv guest pseudo physical address into dom0?
At 17:26 +0800 on 27 Jun (1309195596), Wei Liu wrote: > > You need to arrange for the Xen specific bit of the virtio frontend to > > do the p2m translation. All externally visible addresses from a PV guest > > must be in MFN space. > > > > That's not a good approach. Dirvers reside on a higher level from the > "Xen specific bit". Doing this kind of translation will break their > generality. But there seems no other way to get this job done... This is a general problem with operating systems: bus addresses are not always the same as CPU memory addresses (even though in the easy case of a simple x86 PC they often are). This is why OSes already have interfaces to allocate DMA-able memory and to translate between the address that CPU will map and the one the peripheral should use. If your driver's not using the right address-space to program its hardware it is broken; the Xen PV model is just an extreme case of this. Tim. -- Tim Deegan <Tim.Deegan@xxxxxxxxxx> Principal Software Engineer, Xen Platform Team Citrix Systems UK Ltd. (Company #02937203, SL9 0BG) _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxxxxxxxx http://lists.xensource.com/xen-devel
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