Re: [Qemu-devel] [PATCH] vl: exit if a bad property value is passed to -global

[Greg Kurz <groug@kaod.org>]

On Wed, 20 Jul 2016 17:18:26 -0300
Eduardo Habkost <ehabkost@redhat.com> wrote:

> Sorry for the long delay:
> 
> On Thu, Jul 14, 2016 at 10:29:57AM +0200, Igor Mammedov wrote:
> > On Thu, 14 Jul 2016 11:42:40 +1000
> > David Gibson <david@gibson.dropbear.id.au> wrote:
> >   
> > > On Wed, Jul 13, 2016 at 08:05:03PM +0200, Greg Kurz wrote:  
> > > > When passing '-global driver=host-powerpc64-cpu,property=compat,value=foo'
> > > > on the command line, without this patch, we get the following warning per
> > > > device (which means many lines if the guests has many cpus):
> > > > 
> > > > qemu-system-ppc64: Warning: can't apply global host-powerpc64-cpu.compat=foo:
> > > >     Invalid compatibility mode "foo"
> > > > 
> > > > ... and QEMU continues execution, ignoring the property.
> > > > 
> > > > With this patch, we get a single line:
> > > > 
> > > > qemu-system-ppc64: can't apply global host-powerpc64-cpu.compat=foo:
> > > >     Invalid compatibility mode "foo"
> > > > 
> > > > ... and QEMU exits.
> > > > 
> > > > Signed-off-by: Greg Kurz <groug@kaod.org>    
> > > 
> > > Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
> > > 
> > > Not really up to me to decide if this is the right approach for global
> > > option handling, but it seems like the way to go to me.  
> > CCing Eduardo
> >  as he basically rewrote that path several times and might know why it's this way now.
> >   
> > >   
> > > > ---
> > > >  vl.c |    3 ++-
> > > >  1 file changed, 2 insertions(+), 1 deletion(-)
> > > > 
> > > > diff --git a/vl.c b/vl.c
> > > > index 356713ea075c..a7cc92781687 100644
> > > > --- a/vl.c
> > > > +++ b/vl.c
> > > > @@ -2922,6 +2922,7 @@ static int global_init_func(void *opaque, QemuOpts *opts, Error **errp)
> > > >      g->property = qemu_opt_get(opts, "property");
> > > >      g->value    = qemu_opt_get(opts, "value");
> > > >      g->user_provided = true;
> > > > +    g->errp = errp;  
> 
> Exiting QEMU like you suggest is valid, but we can't set errp to
> error_fatal here, because it could make QEMU abort when using
> device_add.
> 

Indeed QEMU exits :\

> Probably the simplest solution is to ignore GlobalProperty.errp
> in qdev_prop_set_globals_for_type() if dev->hotplugged is set.
> Then we can safely set errp here.
> 

That should do the trick. I'll send a v2.

Thanks !

--
Greg