On Tue, Apr 5, 2022, at 11:30 AM, Sean Christopherson wrote: > On Tue, Apr 05, 2022, Andy Lutomirski wrote: > >> resume guest >> *** host -> hypervisor -> guest *** >> Guest unshares the page. >> *** guest -> hypervisor *** >> Hypervisor removes PTE. TLBI. >> *** hypervisor -> guest *** >> >> Obviously considerable cleverness is needed to make a virt IOMMU like this >> work well, but still. >> >> Anyway, my suggestion is that the fd backing proposal get slightly modified >> to get it ready for multiple subtypes of backing object, which should be a >> pretty minimal change. Then, if someone actually needs any of this >> cleverness, it can be added later. In the mean time, the >> pread()/pwrite()/splice() scheme is pretty good. > > Tangentially related to getting private-fd ready for multiple things, > what about > implementing the pread()/pwrite()/splice() scheme in pKVM itself? I.e. > read() on > the VM fd, with the offset corresponding to gfn in some way. > Hmm, could make sense.
