[SeaBIOS] Use SeaBIOS as UEFI CSM

[Kevin O'Connor]

On Wed, Oct 31, 2018 at 08:17:37AM +0100, Roderick Klein wrote:
> Hello Paul,
> 
> I am the president of the Dutch OS/2 VOICE organisation. I have also kind of
> been lurking here look at this possibility. Instead of modiying legacy OS'es
> I was wondering if a UEFI loader could be created with SeaBIOS build in. I
> think I did ask the question once on this list but never got a reply. Off to
> work!

To the best of my knowledge, one can't get full BIOS compatibility
from a "UEFI loader" as the BIOS really needs to be in the
0xf0000-0x100000 area of memory and that gets locked down by the
firmware.  It might be possible to "hack" SeaBIOS to run in an area of
memory outside of that range, but I suspect it would be a large amount
of work with little gain.  It would almost certainly be simpler to run
a Linux image and then launch the desired OS via QEMU.

-Kevin