Re: [Qemu-ppc] [Qemu-devel] [PATCH] Add nvram to default boot device list

[David Gibson]

On Thu, Oct 11, 2012 at 07:34:42AM +0530, Avik Sil wrote:
> This patch adds nvram specified boot device into qemu default
> boot_devices list. This helps firmware to boot from nvram specified
> boot device if no -boot option is specified.

I really don't think this is a good idea, it extends an already
deprecated mechanism in a fuzzy way and requires careful checking to
see if it could break anything.  On all platforms the boot sequence
should be:
        if bootindex is specified:
                boot according to bootindex
        else if -boot is specified:
                boot according to -boot sequence
        else:
                use platform firmware default sequence

The last will of course vary by platform, and could depend on platform
details like the contents of NVRAM.  Your original idea of making it
clear to the guest when -boot has been specified (as opposed to when
it contains its default value) was the right one, and this "x" in
-boot is going the wrong direction.

-- 
David Gibson                    | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au  | minimalist, thank you.  NOT _the_ _other_
                                | _way_ _around_!
http://www.ozlabs.org/~dgibson