Christian Borntraeger <borntrae...@de.ibm.com> wrote: > Am 08.07.2015 um 14:25 schrieb Juan Quintela: >> Christian Borntraeger <borntrae...@de.ibm.com> wrote: >>> Am 08.07.2015 um 14:08 schrieb Juan Quintela: >>>> Christian Borntraeger <borntrae...@de.ibm.com> wrote: >>>>> Am 07.07.2015 um 15:08 schrieb Juan Quintela: >>>>>> This includes a new section that for now just stores the current qemu >>>>>> state. >>>>>> >>>>>> Right now, there are only one way to control what is the state of the >>>>>> target after migration. >>>>>> >>>>>> - If you run the target qemu with -S, it would start stopped. >>>>>> - If you run the target qemu without -S, it would run just after >>>>>> migration finishes. >>>>>> >>>>>> The problem here is what happens if we start the target without -S and >>>>>> there happens one error during migration that puts current state as >>>>>> -EIO. Migration would ends (notice that the error happend doing block >>>>>> IO, network IO, i.e. nothing related with migration), and when >>>>>> migration finish, we would just "continue" running on destination, >>>>>> probably hanging the guest/corruption data, whatever. >>>>>> >>>>>> Signed-off-by: Juan Quintela <quint...@redhat.com> >>>>>> Reviewed-by: Dr. David Alan Gilbert <dgilb...@redhat.com> >>>>> >>>>> This is bisected to cause a regression on s390. >>>>> >>>>> A guest restarts (booting) after managedsave/start instead of continuing. >>>>> >>>>> Do you have any idea what might be wrong? >>>> >>>> Can you check the new patch series that I sent. There is a fix that >>>> *could* help there. *could* because I don't fully understand why it can >>>> give you problems (and even only sometimes). Current guess is that some >>>> of the devices are testing the guest state on LOAD, so that patch. >>>> >>>> Please, test. >>> >>> That patch does indeed fix my problem. >>> I can see that virtio_init uses the runstate to set vm_running of the vdev. >>> This >>> is used in virtio-net for several aspects. >>> But I really dont understand why this causes the symptoms. >>> So I am tempted to add >>> a >>> Tested-by: Christian Borntraeger <borntrae...@de.ibm.com> >>> >>> but I have a bad feeling on the "why" :-/ >> >> The other reason of that patch is that it removes the need that the >> global_state is the last migration section. > > Hmm, we have some register_savevm here and there, but these seem > to be called in device realize/init or machine init. > > >> Could it be that you are >> adding sections after you launch qemu? Or that virtio devices are >> generated later on s390 for any reason? > > Not that I am aware of. There can be hotplug of course, but I dont see > why libvirt should do that during migration.
It can also happens if it plugs the devices after we have registerd the global save state. On x86_64 that don't happens, but not sure how things are structured in s390. If it was that, it has been fixed with the patch that I sent. > > Still looking..... Thanks, Juan.