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

[Alexander Graf]

On 12.10.2012, at 00:59, David Gibson wrote:

> 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.

Given that this is a fundamental direction for a bunch of machines, how about 
we talk about it on the weekly QEMU call?


Alex