Re: [Qemu-devel] [PATCH 11/12 v2] qmp: add cpu-set qmp command

[Luiz Capitulino <lcapitulino@redhat.com>]

On Tue, 26 Mar 2013 14:43:01 +0100
Igor Mammedov <imammedo@redhat.com> wrote:

> On Mon, 25 Mar 2013 14:22:36 -0600
> Eric Blake <eblake@redhat.com> wrote:
> 
> > On 03/25/2013 02:09 PM, Luiz Capitulino wrote:
> > > On Mon, 25 Mar 2013 16:35:11 +0100
> > > Igor Mammedov <imammedo@redhat.com> wrote:
> > > 
> > 
> > >> +void qmp_cpu_set(int64_t id, const bool online, Error **errp)
> > >> +{
> > >> +    if (online) {
> > >> +        do_cpu_hot_add(id, errp);
> > >> +    } else {
> > >> +        error_setg(errp, "Unplug is not implemented");
> > >> +    }
> > >> +}
> > > 
> > > As a general rule, we don't allow command extensions to be done this
> > > way because this is not queriable. A client would have to try online=off
> > > to see if QEMU version X supports it, worse: the client would have to
> > > parse the error message to be sure the failure actually corresponds
> > > to unplug not implemented.
> > > 
> > > The alternative is to have cpu-set-online and later cpu-set-offline. Quite
> > > verbose, but doesn't have issues.
> It looks like better as way to go. Later on we could keep them for
> compatibility sake and map it to device_add/device_del commands when they are
> ready.

I find the batch API to be a bit overkill (I'd add it in the future if really
needed), but I won't oppose to it.