Re: [PATCH] fw_cfg: Allow reboot-timeout=-1 again

["Dr. David Alan Gilbert" <dgilbert@redhat.com>]

* Markus Armbruster (armbru@redhat.com) wrote:
> "Dr. David Alan Gilbert (git)" <dgilbert@redhat.com> writes:
> 
> > From: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
> >
> > Commit ee5d0f89de3e53cdb0dc added range checking on reboot-timeout
> > to only allow the range 0..65535; however both qemu and libvirt document
> > the special value -1  to mean don't reboot.
> > Allow it again.
> >
> > Fixes: ee5d0f89de3e53cdb0dc ("fw_cfg: Fix -boot reboot-timeout error checking")
> > RH bz: https://bugzilla.redhat.com/show_bug.cgi?id=1765443
> > Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
> > ---
> >  hw/nvram/fw_cfg.c | 5 +++--
> >  1 file changed, 3 insertions(+), 2 deletions(-)
> >
> > diff --git a/hw/nvram/fw_cfg.c b/hw/nvram/fw_cfg.c
> > index 7dc3ac378e..1a9ec44232 100644
> > --- a/hw/nvram/fw_cfg.c
> > +++ b/hw/nvram/fw_cfg.c
> > @@ -247,10 +247,11 @@ static void fw_cfg_reboot(FWCfgState *s)
> >  
> >      if (reboot_timeout) {
> >          rt_val = qemu_opt_get_number(opts, "reboot-timeout", -1);
> > +
> >          /* validate the input */
> > -        if (rt_val < 0 || rt_val > 0xffff) {
> > +        if (rt_val < -1 || rt_val > 0xffff) {
> >              error_report("reboot timeout is invalid,"
> > -                         "it should be a value between 0 and 65535");
> > +                         "it should be a value between -1 and 65535");
> >              exit(1);
> >          }
> >      }
> 
> Semantic conflict with "PATCH] qemu-options.hx: Update for
> reboot-timeout parameter", Message-Id:
> <20191015151451.727323-1-hhan@redhat.com>.

Thanks for spotting that.
I think Han and also submitted patches to review it from libvirt
and it wasn't obvious what to do.  (Cc'd Han in).

> I'm too tired right now to risk an opinion on which one we want.

As is everyone else !  The problem here is that its documented
as a valid thing to do, and libvirt does it, and you might have 
a current XML file that did it.  Now I think you could change libvirt
to omit the reboot-timeout parameter if it was called with -1.

So given its a documented thing in both qemu and libvirt xml
if we want to remove it then it sohuld be deprecated properly - but it's
already broken.

Dave

--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK