Re: [Qemu-devel] [PATCH 4/6] monitor: check if chardev can switch gcontext for OOB

[Peter Xu <peterx@redhat.com>]

On Tue, Oct 09, 2018 at 05:12:49PM +0400, Marc-André Lureau wrote:
> Note: this patch will conflict with Peter "[PATCH v9 3/6] monitor:
> remove "x-oob", turn oob on by default", but can be trivially updated.
> 
> Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
> ---
>  monitor.c | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/monitor.c b/monitor.c
> index a25514490a..c175cf6f0d 100644
> --- a/monitor.c
> +++ b/monitor.c
> @@ -4550,9 +4550,10 @@ void monitor_init(Chardev *chr, int flags)
>      bool use_oob = flags & MONITOR_USE_OOB;
>  
>      if (use_oob) {
> -        if (CHARDEV_IS_MUX(chr)) {
> +        if (!qemu_chr_has_feature(chr, QEMU_CHAR_FEATURE_GCONTEXT)) {
>              error_report("Monitor out-of-band is not supported with "
> -                         "MUX typed chardev backend");
> +                         "%s typed chardev backend",
> +                         object_get_typename(OBJECT(chr)));

This seems a bit confusing to me at the first glance since we forbid
mux because not all frontends are ready to run outside main loop (and
now we have mon_iothread so it'll be odd too to run anything
non-monitor on that too...), rather than whether the backend can
dynamically switch its context.

I'm not sure, but do you mean you want to disable oob for backends
like spice or braille?  I just noticed that it seems even legal if we
pipe a qmp monitor with a windows mouse...

I believe in all cases the commit message can be enhanced on
explaining "why" of this patch. :)

Regards,

-- 
Peter Xu