[SeaBIOS] SeaBIOS as EFI application

[Jordan Justen]

On Sat, Nov 10, 2012 at 1:07 PM, Kevin O'Connor <kevin at koconnor.net> wrote:
> On Sat, Nov 10, 2012 at 11:30:39AM -0800, Jordan Justen wrote:
>> On Sat, Nov 10, 2012 at 8:25 AM, Thorsten Glaser <tg at mirbsd.de> wrote:
>> > Kevin O'Connor dixit:
>> >>1 - Using SeaBIOS as a CSM.  The CSM spec is amazingly complex as
>> >
>> >>2 - Implementing in SeaBIOS a subset of the EFI OS interface so that
>> >
>> > Both aren’t really what I want.
>>
>> It sounds like you definitely don't want 2, but you do want something
>> similar to 1. In a UEFI+CSM system, the CSM essentially provides the
>> environment that legacy BIOS based software can use.
>
> I don't think one can add a CSM to an existing machine though.

I think you could load it similarly to an OS, but what you load would
probably require some chipset/platform knowledge.

> So, if
> you're looking to boot DOS from a machine with an off-the-shelf UEFI
> implementation without a CSM then I don't think adding a CSM will
> work.

Yes, I think you are correct, due to the chipset/platform legacy
pieces that likely aren't provided in a non-CSM UEFI system.

-Jordan