[SeaBIOS] [SeaBIOS PATCH v2] boot: support strict boot and make it configurable

[Amos Kong]

On Tue, Jan 08, 2013 at 11:00:42PM -0500, Kevin O'Connor wrote:
> On Wed, Dec 26, 2012 at 08:55:40AM +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.
> > 
> > We need to make it configurable, seabios user can config it by a rom
> > file('etc/boot-strict'). 'strict boot' means only boot from user
> > selected devices.
> > 
> > I added some comments in this patch to explain why we can judge if
> > device is selected or not by DEFAULT_PRIO(9999). I also added 'selected'
> > flag in struct bootentry_s and struct bev_s to make it clearer.
> > 
> > If this patch is accepted, I will add a boot option (-boot strict=on)
> > for qemu.
> 
> I think it would be simpler to use the existing bootorder file instead
> of introducing a new "boot-strict" file.  Something like the below
> (untested).

Thanks for your patch. It's good. I thought you suggest me to add a
new type, and bootentry_add unselected devices to HALT type.

I did a simple test, patch works. I will re-post this patch and change
qemu code to use this new type.

Amos
 
> -Kevin
> 
> 
> diff --git a/src/boot.c b/src/boot.c
> index c67cc7f..56843e3 100644
> --- a/src/boot.c
> +++ b/src/boot.c
> @@ -291,6 +291,7 @@ static struct bootentry_s *BootList;
>  #define IPL_TYPE_CBFS        0x20
>  #define IPL_TYPE_BEV         0x80
>  #define IPL_TYPE_BCV         0x81
> +#define IPL_TYPE_HALT        0xf0
>  
>  static void
>  bootentry_add(int type, int prio, u32 data, const char *desc)
> @@ -488,6 +489,10 @@ boot_prep(void)
>      interactive_bootmenu();
>      wait_threads();
>  
> +    int haltprio = find_prio("HALT");
> +    if (haltprio >= 0)
> +        bootentry_add(IPL_TYPE_HALT, haltprio, 0, "HALT");
> +
>      // Map drives and populate BEV list
>      struct bootentry_s *pos = BootList;
>      while (pos) {
> @@ -672,6 +677,9 @@ do_boot(int seq_nr)
>      case IPL_TYPE_BEV:
>          boot_rom(ie->vector);
>          break;
> +    case IPL_TYPE_HALT:
> +        boot_fail();
> +        break;
>      }
>  
>      // Boot failed: invoke the boot recovery function