Re: [Qemu-devel] [RFC][PATCH 0/6] "bootonceindex" property

[Huttunen, Janne (Nokia - FI/Espoo)]

On Wed, 2017-03-22 at 04:43 -0400, Paolo Bonzini wrote:
> 
> Understood---my question is how you would set up the alternate
> boot order: is it something like "keep a button pressed while
> turning on", or something written in NVRAM, or something else
> that is completely different?

In my case the real hardware has a management processor
on the board and the temporary boot source (and also the
permanent one for that matter) for the main processor can
be set from there. Since neither the BIOS nor the management
firmware are open source, I don't know how it technically
works, but I assume there either is some shared memory
between the main BIOS and the management processor or
alternatively the BIOS talks with the management processor
with some protocol during boot to get the order.