[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] PCI Passthrough ARM Design : Draft1
On Thu, 11 Jun 2015, Ian Campbell wrote: > On Thu, 2015-06-11 at 07:25 -0400, Julien Grall wrote: > > Hi Ian, > > > > On 11/06/2015 04:56, Ian Campbell wrote: > > > On Wed, 2015-06-10 at 15:21 -0400, Julien Grall wrote: > > >> Hi, > > >> > > >> On 10/06/2015 08:45, Ian Campbell wrote: > > >>>> 4. DomU access / assignment PCI device > > >>>> -------------------------------------- > > >>>> When a device is attached to a domU, provision has to be made such that > > >>>> it can > > >>>> access the MMIO space of the device and xen is able to identify the > > >>>> mapping > > >>>> between guest bdf and system bdf. Two hypercalls are introduced > > >>> > > >>> I don't think we want/need new hypercalls here, the same existing > > >>> hypercalls which are used on x86 should be suitable. That's > > >>> XEN_DOMCTL_memory_mapping from the toolstack I think. > > >> > > >> XEN_DOMCTL_memory_mapping is done by QEMU for x86 HVM when the guest > > >> (i.e hvmloader?) is writing in the PCI BAR. > > > > > > What about for x86 PV? I think it is done by the toolstack there, I > > > don't know what pciback does with accesses to BAR registers. > > > > XEN_DOMCTL_memory_mapping is only used to map memory in stage-2 page > > table. This is only used for auto-translated guest. > > > > In the case of x86 PV, the page-table is managed by the guest. The only > > things to do is to give the MMIO permission to the guest in order to the > > let him use them. This is done at boot time in the toolstack. > > Ah yes, makes sense. > > Manish, this sort of thing and the constraints etc should be discussed > in the doc please. I think that the toolstack (libxl) will need to call xc_domain_memory_mapping (XEN_DOMCTL_memory_mapping), in addition to xc_domain_iomem_permission, for auto-translated PV guests on x86 (PVH) and ARM guests. _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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