Re: [Qemu-devel] [PATCH v4 6/7] Make the kernel image in the fw_cfg DMA interface bootable

[Kevin O'Connor]

On Fri, Oct 02, 2015 at 10:09:17AM +0200, Gerd Hoffmann wrote:
> > - read four bytes from under the fw_cfg selector QEMU_CFG_KERNEL_SIZE
> >   (0x0008),
> > - if it is zero,    return -1 --> no kernel boot requested,
> > - if it is nonzero, return  0 --> which means "top priority".
> > 
> > In other words, I agree with:
> > 
> > > -    option_rom[nb_option_roms].bootindex = 0;
> > > +    option_rom[nb_option_roms].bootindex = 1;

The bootindex in QEMU is not visible in the firmware, so if the rest
of patch 6 is dropped then the above should be dropped as well.

> Hmm.  That makes the boot order undefined for "qemu -kernel foo -device
> virtio-blk,drive=bar,bootindex=1" when using an old seabios.  I don't
> think this is a good idea.

Wouldn't that make the bootorder undefined everywhere?  What does it
mean to use -kernel and specify a bootorder?

-Kevin