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Date: Fri, 2 Oct 2015 10:24:08 +0200
From: Marc =?UTF-8?B?TWFyw60=?= <markmb@redhat.com>
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Subject: Re: [Qemu-devel] [PATCH v4 6/7] Make the kernel image in the fw_cfg
 DMA interface bootable
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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, Kevin O'Connor <kevin@koconnor.net>, Laszlo Ersek <lersek@redhat.com>

On Fri, 02 Oct 2015 10:16:26 +0200
Gerd Hoffmann <kraxel@redhat.com> wrote:

>   Hi,
> 
> > That's fine with me.  Marc - I think qemu_vmlinux_setup() in SeaBIOS
> > with the following would work:
> > 
> > void qemu_vmlinux_setup(void)
> > {
> >     u32 kernel_size;
> >     qemu_cfg_read_entry(&kernel_size, QEMU_CFG_KERNEL_SIZE,
> > sizeof(kernel_size)); if (kernel_size)
> >         boot_add_qemu_vmlinux("QEMU Kernel image", 0);
> > }
> 
> It isn't that simple.  We also have support for multiboot kernels
> (using multiboot.bin option rom).  So when doing this you need to be
> prepared to find a multiboot kernel in fw_cfg.
> 
> cheers,
>   Gerd

A solution that I can see is adding DMA boot capabilities to the
linuxboot.S optionrom. I was trying to avoid this, but it looks like
not doing so creates lots of problems. It may be better than adding a
"nice" shortcut somewhere in QEMU or SeaBIOS.

Who uses this optionrom (and will benefit from this change)?

Thanks
Marc