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

[Gerd Hoffmann]

  Hi,

> 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)?

Any -kernel boot on x86 will use either linuxboot.bin or multiboot.bin.

>From a compatibility point of view implementing it in the option rom
certainly has its advantages.  And as the option roms are shipped with
and loaded by qemu you don't even have to do runtime detection if that
simplifies things.  We can just build two versions of the roms and qemu
can use the one or the other depending on whenever the machine type in
question has fw_cfg dma enabled or not.

cheers,
  Gerd