Date: Fri, 2 Oct 2015 09:40:41 -0400
From: Kevin O'Connor <kevin@koconnor.net>
Message-ID: <20151002134041.GB16190@morn.lan>
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Subject: Re: [Qemu-devel] [PATCH v4 6/7] Make the kernel image in the fw_cfg
 DMA interface bootable
To: Gerd Hoffmann <kraxel@redhat.com>
Cc: Drew <drjones@redhat.com>, Stefan Hajnoczi <stefanha@gmail.com>, "Gabriel L. Somlo" <somlo@cmu.edu>, qemu-devel@nongnu.org, Marc =?iso-8859-1?Q?Mar=ED?= <markmb@redhat.com>, Laszlo Ersek <lersek@redhat.com>

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