Re: [Qemu-devel] [Resend][Seabios PATCH] don't boot from un-selected devices

[Amos Kong <akong@redhat.com>]

On Wed, Dec 19, 2012 at 11:32:08AM +0200, Gleb Natapov wrote:
> On Wed, Dec 19, 2012 at 03:24:45PM +0800, Amos Kong wrote:
> > Current seabios will try to boot from selected devices first,
> > if they are all failed, seabios will also try to boot from
> > un-selected devices.
> > 
> > For example:
> > @ qemu-kvm -boot order=n,menu=on ...
> > 
> > Guest will boot from network first, if it's failed, guest will try to
> > boot from other un-selected devices (floppy, cdrom, disk) one by one.
> > 
> > Sometimes, user don't want to boot from some devices. This patch changes

Hi Gleb,

> And sometimes he want. The patch changes behaviour unconditionally. New
> behaviour should be user selectable. Something line -boot order=strict
> on qemu command line.

Sometimes, user don't know which devices are in boot list of seabios,
so they could not disable them through qemu cmdline.

I didn't describe the purpose clearly. Currently we can assign boot
order by "-boot order=...", if fails to boot from all devices in order
parameters, other devices in seabios's boot table will also be tried. 

The exact request should be "only boot from selected devices".

I agree to make it configurable.
eg:  qemu -boot order=nd,strict=on,menu=on
     strick: on  (only boot from selected devices)
     strick: off  (will try to boot from all devices in seabios' boot table)
     default strick should be 'off' as current behavior.
 
Thanks, Amos

> > seabios to boot only from selected devices.
> > 
> > If user choose first boot device from menu, then seabios will try all
> > the devices, even some of them are not selected.
> > 
> > Signed-off-by: Amos Kong <akong@redhat.com>
> > ---
> > Resend for CCing seabios maillist.
> > ---
> >  src/boot.c |   13 ++++++++-----
> >  1 files changed, 8 insertions(+), 5 deletions(-)
> > 
> > diff --git a/src/boot.c b/src/boot.c
> > index 3ca7960..ee810ac 100644
> > --- a/src/boot.c
> > +++ b/src/boot.c
> > @@ -424,6 +424,10 @@ interactive_bootmenu(void)
> >          maxmenu++;
> >          printf("%d. %s\n", maxmenu
> >                 , strtcpy(desc, pos->description, ARRAY_SIZE(desc)));
> > +        /* If user chooses first boot device from menu, we will treat
> > +	    all the devices as selected. */
> > +        if (pos->priority == DEFAULT_PRIO)
> > +            pos->priority = DEFAULT_PRIO - 1;
> >          pos = pos->next;
> >      }
> >  
> > @@ -490,7 +494,10 @@ boot_prep(void)
> >  
> >      // Map drives and populate BEV list
> >      struct bootentry_s *pos = BootList;
> > -    while (pos) {
> > +
> > +    /* The priority of un-selected device is not changed,
> > +       we only boot from user selected devices. */
> > +    while (pos && pos->priority != DEFAULT_PRIO) {
> >          switch (pos->type) {
> >          case IPL_TYPE_BCV:
> >              call_bcv(pos->vector.seg, pos->vector.offset);
> > @@ -513,10 +520,6 @@ boot_prep(void)
> >          }
> >          pos = pos->next;
> >      }
> > -
> > -    // If nothing added a floppy/hd boot - add it manually.
> > -    add_bev(IPL_TYPE_FLOPPY, 0);
> > -    add_bev(IPL_TYPE_HARDDISK, 0);