On Wed, 6 Jul 2016 08:05:15 +0200 Paolo Bonzini <pbonzini@xxxxxxxxxx> wrote: > On 06/07/2016 04:00, 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. > > I think that this fixes a bug anyway, the previous handling of VM_PFNMAP > is too simplistic. Agreed, no reason to hold off on this, it's a valid interaction that needs to be fixed regardless of how or if the vfio mediated driver makes use of it. Thanks, Alex -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
