On Wed, Jul 06, 2016 at 10:35:18AM +0800, Xiao Guangrong wrote: > > > On 07/06/2016 10:18 AM, Neo Jia wrote: > >On Wed, Jul 06, 2016 at 10:00:46AM +0800, Xiao Guangrong wrote: > >> > >> > >>On 07/05/2016 08:18 PM, Paolo Bonzini wrote: > >>> > >>> > >>>On 05/07/2016 07:41, Neo Jia wrote: > >>>>On Thu, Jun 30, 2016 at 03:01:49PM +0200, Paolo Bonzini wrote: > >>>>>The vGPU folks would like to trap the first access to a BAR by setting > >>>>>vm_ops on the VMAs produced by mmap-ing a VFIO device. The fault handler > >>>>>then can use remap_pfn_range to place some non-reserved pages in the VMA. > >>>>> > >>>>>KVM lacks support for this kind of non-linear VM_PFNMAP mapping, and > >>>>>these > >>>>>patches should fix this. > >>>> > >>>>Hi Paolo, > >>>> > >>>>I have tested your patches with the mediated passthru patchset that is > >>>>being > >>>>reviewed in KVM and QEMU mailing list. > >>>> > >>>>The fault handler gets called successfully and the previously mapped > >>>>memory gets > >>>>unmmaped correctly via unmap_mapping_range. > >>> > >>>Great, then I'll include them in 4.8. > >> > >>Code is okay, but i still suspect if this implementation, fetch mmio pages > >>in fault > >>handler, is needed. We'd better include these patches after the design of > >>vfio > >>framework is decided. > > > >Hi Guangrong, > > > >I disagree. The design of VFIO framework has been actively discussed in the > >KVM > >and QEMU mailing for a while and the fault handler is agreed upon to provide > >the > >flexibility for different driver vendors' implementation. With that said, I > >am > >still open to discuss with you and anybody else about this framework as the > >goal > >is to allow multiple vendor to plugin into this framework to support their > >mediated device virtualization scheme, such as Intel, IBM and us. > > The discussion is still going on. And current vfio patchset we reviewed is > still > problematic.
My point is the fault handler part has been discussed already, with that said I am always open to any constructive suggestions to make things better and maintainable. (Appreciate your code review on the VFIO thread, I think we still own you another response, will do that.) > > > > >May I ask you what the exact issue you have with this interface for Intel to > >support > >your own GPU virtualization? > > Intel's vGPU can work with this framework. We really appreciate your / > nvidia's > contribution. Then, I don't think we should embargo Paolo's patch. > > i didn’t mean to offend you, i just want to make sure if this complexity is > really > needed and inspect if this framework is safe enough and think it over if we > have > a better implementation. Not at all. :-) Suggestions are always welcome, I just want to know the exact issues you have with the code so I can have a better response to address that with proper information. Thanks, Neo
