Re: [Qemu-devel] nvram and boot order

[Gleb Natapov <gleb@redhat.com>]

On Wed, Oct 17, 2012 at 07:07:53AM +1100, Benjamin Herrenschmidt wrote:
> On Tue, 2012-10-16 at 14:55 -0500, Anthony Liguori wrote:
> > 
> > 4) If -boot is specified, the parameter should alter the contents of
> >    NVRAM to change the boot order to what is specified by -boot.
> > 
> > 5) If ,bootorder is specified, it should take predence over -boot.
> > 
> > 6) ,bootorder= should also alter the contents of NVRAM to determine
> > the
> >    boot order
> 
> That's where I disagree. At least for us... I don't see why -boot or
> -bootorder should alter the nvram content.
> 
> The plan is to have the nvram content essentially in control of SLOF
> (ie. the BIOS in x86 land). Qemu doesn't know much of anything appart
> from providing the storage for it.
> 
> I see -boot and -bootorder as ways to *temporarily* override whatever
> setting was put in nvram by the guest. The nvram is typically populated
> by the distro installer (though sometimes by hand by the user). One may
> want to just temporarily boot from a CD (rescue for example, or to test
> a live CD or something ...), that doesn't mean the permanent setting
> should be altered.
> 
> I would pass -boot and -bootorder to SLOF like we pass the current
> bootlist today and let it deal with it, I wouldn't touch the nvram.
> 
Agree with you and David. This is not QEMU busyness to touch nvram
content. For all we know it may be encrypted by a key knows only to
the firmware.

--
			Gleb.