Re: [Qemu-devel] [PATCH v3 5/6] s390x/css: activate ChannelSubSys migration

[Cornelia Huck <cohuck@redhat.com>]

On Tue, 3 Oct 2017 13:58:29 +0200
Thomas Huth <thuth@redhat.com> wrote:

> On 11.07.2017 16:54, Halil Pasic wrote:
> > Turn on migration for the channel subsystem for the next machine.  For
> > legacy machines we still have to do things the old way.
> > 
> > Signed-off-by: Halil Pasic <pasic@linux.vnet.ibm.com>
> > Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
> > ---
> >  hw/s390x/css.c             | 5 +++++
> >  hw/s390x/s390-virtio-ccw.c | 9 ++++-----
> >  include/hw/s390x/css.h     | 4 ++++
> >  3 files changed, 13 insertions(+), 5 deletions(-)
> > 
> > diff --git a/hw/s390x/css.c b/hw/s390x/css.c
> > index 20b5fbed68..b89b60751a 100644
> > --- a/hw/s390x/css.c
> > +++ b/hw/s390x/css.c
> > @@ -407,6 +407,11 @@ static int subch_dev_post_load(void *opaque, int version_id)
> >      return 0;
> >  }
> >  
> > +void css_register_vmstate(void)
> > +{
> > +    vmstate_register(NULL, 0, &vmstate_css, &channel_subsys);
> > +}
> > +
> >  IndAddr *get_indicator(hwaddr ind_addr, int len)
> >  {
> >      IndAddr *indicator;
> > diff --git a/hw/s390x/s390-virtio-ccw.c b/hw/s390x/s390-virtio-ccw.c
> > index 751febb87a..20e3f06519 100644
> > --- a/hw/s390x/s390-virtio-ccw.c
> > +++ b/hw/s390x/s390-virtio-ccw.c
> > @@ -206,7 +206,7 @@ static void ccw_machine_class_init(ObjectClass *oc, void *data)
> >  
> >      s390mc->ri_allowed = true;
> >      s390mc->cpu_model_allowed = true;
> > -    s390mc->css_migration_enabled = false; /* TODO: set to true */
> > +    s390mc->css_migration_enabled = true;
> >      mc->init = ccw_init;
> >      mc->reset = s390_machine_reset;
> >      mc->hot_add_cpu = s390_hot_add_cpu;
> > @@ -482,10 +482,9 @@ bool css_migration_enabled(void)
> >  
> >  static void ccw_machine_2_10_instance_options(MachineState *machine)
> >  {
> > -    /*
> > -     * TODO Once preparations are done register vmstate for the css if
> > -     * css_migration_enabled().
> > -     */
> > +    if (css_migration_enabled()) {
> > +        css_register_vmstate();
> > +    }
> >  }  
> 
> The location for the above hunk seems to be quite unfortunate: For the
> s390-ccw-virtio-2.11 machine, we now do not call css_register_vmstate()
> anymore.

Hm, you're right... only setting the boolean should be done in the
compat callbacks.

> 
> Maybe this should rather go into ccw_init() instead?

Sounds reasonable. Halil, can you please check (and send a patch if it
makes sense?)