Re: [Qemu-devel] [Qemu-ppc] Qemu boot device precedence over nvram boot-device setting

[Avik Sil]

> > > > I looked at the bootindex stuff and found that when the bootindex is
> > > > specified for the disk and cdrom it generates a string like:
> > > >
> > > > "/spapr-vio-bridge/spapr-vscsi/address@hidden/address@hidden,1
> > > > /spapr-vio-bridge/spapr-vscsi/address@hidden/address@hidden,0"
> > > >
> > > > Now converting/translating this to OF device path is going to be
> > > > much trickier and might not be proper. So I propose a simple
> > > > solution by introducing a global flag that checks if explicit -boot
> > > > parameter is provided or not. The presence of this parameter is
> > > > verified in SLOF firmware. The flag had to be introduced as
> > > > boot_devices defaults to "cad" instead of null and passed to
> > > > machine->init().
> > > So you want to hack around the problem. If -boot is specified what
> > > device are you going to boot from?
> >
> > It is going to boot from the device specified in -boot as
> > default_boot_order is set to 0 in that case.
> -boot has not enough verbosity to tell the device to boot from if you
> have more than one device of each type. What are you going to boot from
> if you have two disks, two NICs, etc?

Yes, -boot has this limitation and -boot is what we are currently using. 
We are extending this using the nvram boot-device property. With the 
nvram driver in place, we would be booting from boot-device. We also 
need a way from qemu to override this, where we hit this issue of the 
default boot device. And currently SLOF boots from the first disk/cdrom 
it discovers in device tree in case there are multiple disks or cdroms.

Regards,
Avik

> --
>                         Gleb.