[Qemu-devel] Re: [PATCHv2] Support for booting from virtio disks

[Kevin O'Connor <kevin@koconnor.net>]

On Wed, May 12, 2010 at 10:22:59AM +0300, Avi Kivity wrote:
> On 05/11/2010 03:31 PM, Gleb Natapov wrote:
> >Real BIOS can do that because it enumerates all bootable devices,
> >attach name for each one of them and then asks user to configure
> >boot order using names it attached to devices. In our case we
> >want to provide boot order on qemu command line before BIOS
> >enumerated devices, so qemu should be able to pass enough information
> >about boot device so that BIOS can uniquely identify it after it will
> >discover all bootable devices. bus/device pair can be such thing.
> 
> Having a BIOS menu is also useful, you don't have to drop to the
> management tool, instead you do everything from the console.

Having a "setup menu" is something real hardware could use as well.  I
don't think the setup menu should be in SeaBIOS - instead, SeaBIOS
could launch another program (stored in flash or qemu_fw) dedicated to
doing setup.

> >>Alternatively we can seed the order from the command line (-boot
> >>id1,id2,id3 where id* are some qdev property attached to disks, this
> >>is more flexible than the current syntax I think).
> >>
> >The problem is how to communicate this order to Seabios.
> 
> Topology (bus/device/lun).

USB is a pain here.  It's posible with BDF (Bus/Dev/Fn) and port
number (which accounts for hubs having ports as well).

-Kevin