| Message ID | 9675031ce557b73ebd10e7bd20ebbf57f30b177c.1589193382.git.lukasstraub2@web.de (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | colo: migration related bugfixes | expand |
* Lukas Straub (lukasstraub2@web.de) wrote: > cpu_synchronize_all_pre_loadvm() marks all vcpus as dirty, so the > registers are loaded from CPUState before we continue running > the vm. However if we failover during checkpoint, CPUState is not > initialized and the registers are loaded with garbage. This causes > guest hangs and crashes. > > Fix this by using cpu_synchronize_all_states(), which initializes > CPUState from the current cpu registers additionally to marking > the vcpus as dirty. > > Signed-off-by: Lukas Straub <lukasstraub2@web.de> OK, so I think you're saying that if the qemu_loadvm_state_main fails because we failover, we now have duff CPU state, where we should just carry on running on the secondary with the current state, so yes Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> > --- > migration/colo.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/migration/colo.c b/migration/colo.c > index 09168627bc..6b2ad35aa4 100644 > --- a/migration/colo.c > +++ b/migration/colo.c > @@ -696,7 +696,7 @@ static void colo_incoming_process_checkpoint(MigrationIncomingState *mis, > } > > qemu_mutex_lock_iothread(); > - cpu_synchronize_all_pre_loadvm(); > + cpu_synchronize_all_states(); > ret = qemu_loadvm_state_main(mis->from_src_file, mis); > qemu_mutex_unlock_iothread(); > > -- > 2.20.1 > -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK
On Wed, 13 May 2020 10:47:02 +0100 "Dr. David Alan Gilbert" <dgilbert@redhat.com> wrote: > * Lukas Straub (lukasstraub2@web.de) wrote: > > cpu_synchronize_all_pre_loadvm() marks all vcpus as dirty, so the > > registers are loaded from CPUState before we continue running > > the vm. However if we failover during checkpoint, CPUState is not > > initialized and the registers are loaded with garbage. This causes > > guest hangs and crashes. > > > > Fix this by using cpu_synchronize_all_states(), which initializes > > CPUState from the current cpu registers additionally to marking > > the vcpus as dirty. > > > > Signed-off-by: Lukas Straub <lukasstraub2@web.de> > > OK, so I think you're saying that if the qemu_loadvm_state_main fails > because we failover, we now have duff CPU state, where we should just > carry on running on the secondary with the current state, so yes Exactly, Sorry for my bad wording. > > Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> > > > --- > > migration/colo.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/migration/colo.c b/migration/colo.c > > index 09168627bc..6b2ad35aa4 100644 > > --- a/migration/colo.c > > +++ b/migration/colo.c > > @@ -696,7 +696,7 @@ static void colo_incoming_process_checkpoint(MigrationIncomingState *mis, > > } > > > > qemu_mutex_lock_iothread(); > > - cpu_synchronize_all_pre_loadvm(); > > + cpu_synchronize_all_states(); > > ret = qemu_loadvm_state_main(mis->from_src_file, mis); > > qemu_mutex_unlock_iothread(); > > > > -- > > 2.20.1 > > > > > -- > Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK >
diff --git a/migration/colo.c b/migration/colo.c index 09168627bc..6b2ad35aa4 100644 --- a/migration/colo.c +++ b/migration/colo.c @@ -696,7 +696,7 @@ static void colo_incoming_process_checkpoint(MigrationIncomingState *mis, } qemu_mutex_lock_iothread(); - cpu_synchronize_all_pre_loadvm(); + cpu_synchronize_all_states(); ret = qemu_loadvm_state_main(mis->from_src_file, mis); qemu_mutex_unlock_iothread();
cpu_synchronize_all_pre_loadvm() marks all vcpus as dirty, so the registers are loaded from CPUState before we continue running the vm. However if we failover during checkpoint, CPUState is not initialized and the registers are loaded with garbage. This causes guest hangs and crashes. Fix this by using cpu_synchronize_all_states(), which initializes CPUState from the current cpu registers additionally to marking the vcpus as dirty. Signed-off-by: Lukas Straub <lukasstraub2@web.de> --- migration/colo.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)