On Wed, Feb 26, 2020 at 10:38 PM Paolo Bonzini <pbonzini@xxxxxxxxxx> wrote: > > On 27/02/20 01:22, Oliver Upton wrote: > > Are there any strong opinions about how the newly introduced nested > > state should be handled across live migrations? When applying this > > patch set internally I realized live migration would be busted in the > > case of a kernel rollback (i.e. a kernel with this patchset emits the > > nested state, kernel w/o receives it + refuses). > > Only if you use MTF + emulation. In this case it's a pure bugfix so > it's okay to break backwards migration. If it's really a new feature, > it should support KVM_ENABLE_CAP to enable it. > > Paolo > True. I suppose I've conflated the pure bugfix here with the fact that MTF is new to us. Thanks Paolo! -- Best, Oliver > > Easy fix is to only turn on the feature once it is rollback-proof, but > > I wonder if there is any room for improvement on this topic.. >
