On Sat, Apr 27, 2019 at 03:37:39AM -0400, Paolo Bonzini wrote: > > > > The destination userspace should simply call KVM_SUBPAGES_SET_ACCESS, > > > and KVM will process it just like it would on the source. In other > > > words, it shouldn't matter if the ioctl is done as part of migration or > > > the first time a VM is setup. And in both cases, lazy setup should be > > > fine. > > > > The problem is in current patch (as in link), it assumes > > the target pages are there in EPT, but in migration case, these pages > > are not setup in ETP, so KVM_SUBPAGES_SET_ACCESS during migration or > > destination bootup will fail, should I modify the patch to setup the > > ETP in lazy mode? > > Yes, definitely. Remember that EPT page tables come and go (pages could > be swapped out, or moved from one host physical address to another; there > is also a shrinker that will release EPT page tables if memory is low), > so SPP support should be ready for that. Migration is just a special case. > > Paolo OK, got it, thanks a lot for the reply!
