Hello Boris, Paolo, On Fri, May 14, 2021 at 10:03:18AM +0200, Paolo Bonzini wrote: > On 14/05/21 09:33, Borislav Petkov wrote: > > Ok, so explain to me how this looks from the user standpoint: she starts > > migrating the guest, it fails to lookup an address, there's nothing > > saying where it failed but the guest crashed. > > > > Do you think this is user-friendly? > > Ok, so explain to me how this looks from the submitter standpoint: he reads > your review of his patch, he acknowledges your point with "Yes, it makes > sense to signal it with a WARN or so", and still is treated as shit. > > Do you think this is friendly? > > I absolutely agree with both of your point of view. But what's the alternative ? Ideally we should fail/stop migration even if a single guest page encryption status cannot be notified and that should be the way to proceed in this case, the guest kernel should notify the source userspace VMM to block/stop migration in this case. >From a practical side, i do see Qemu's migrate_add_blocker() interface but that looks to be a static interface and also i don't think it will force stop an ongoing migration, is there an existing mechanism to inform userspace VMM from kernel about blocking/stopping migration ? Thanks, Ashish
