Re: [Qemu-devel] [PATCH 08/11] QMP: Asynchronous messages enable/disable support

[Luiz Capitulino <lcapitulino@redhat.com>]

On Mon, 25 Jan 2010 16:33:02 +0200
Avi Kivity <avi@redhat.com> wrote:

> On 01/25/2010 04:29 PM, Markus Armbruster wrote:
> >
> > I agree with Anthony that async message masking doesn't really affect
> > the protocol proper.  We could pretend it does so we can let protocol
> > capability negotiation (which we need anyway) cover it.  But I'm
> > certainly fine with keeping it separate.
> >
> > Whether we call it protocol or not, the question whether we should
> > permit changing the masks at any time is valid, I think.  Permitting it
> > adds a bit of conceptual complexity, as a command disabling reporting of
> > an event can race with the event.  But that's just giving clients some
> > more rope.  I'm fine with that.
> >    
> 
> Without disagreeing with the rest (which means I'm just nit-picking), 
> there's no race.  Once the command that disables an event report returns 
> to the caller, the event can no longer be reported.

 I wouldn't call it a race, but if you don't want an event you'll have
to deal with it between mode change and masking.

 Not a big deal, only confirms that clients are required to know how to
ignore events, even if masking is available (which I'm not going to
introduce).