Re: [Qemu-devel] [PATCH] x86: Manage BIOS boot menu via command line

[Anthony Liguori <anthony@codemonkey.ws>]

Jan Kiszka wrote:
> Anthony Liguori wrote:
>   
>> Paul Brook wrote:
>>     
>>>
>> Or -boot cad,prompt=[on|off]
>>     
>
> -boot currently takes arbitrary characters from a-z. Adding some
> extension means changing a lot of code (the users are unfortunately not
> well structured right now).

Our user interface should not be dictated by our lack of structure 
internally.  That said, I don't believe it's as bad as you may first think.

If you parse the parameters of the string in vl.c, you can construct a 
new string that just contains "cad" and pass that to machine_init.  That 
makes it pretty straight forward.

>  And how to deal with the monitor interface
> then? Keep it, extend it?

Extend it with the same syntax, in the same fashion.

>  Moreover, how should we express the case of
> enabling the boot menu without providing any boot device,
> "-boot prompt=on"? Then parsing this will be fun - not impossible, for
> sure. But so far I'm looking for a straightforward approach.
>   

I don't know that that syntax is needed.  You could force -boot 
,prompt=on but I think just explicitly specifying -boot cad,prompt=on is 
enough.

>> Or firmware config since that can be shared with non-x86 targets.
>>     
>
> I'm open for the firmware config if you explain to me how state
> information is supposed to be transfered from rombios32.c (where the
> fw_cfg is evaluated) to some function in rombios.c. Tried this but found
> nothing obvious.
>   

Gleb, could you comment here?  I'm obviously ignorant of the firmware 
config code in the BIOS.  It seems like the right thing to use but if 
it's all the current support is in 32-bit code, it may be difficult to 
use that within the 16-bit code without rewriting it all.

Regards,

Anthony Liguori

> Jan
>