[SeaBIOS] How much RAM is required?

[Markus Armbruster]

Peter Stuge <peter at stuge.se> writes:

> Markus Armbruster wrote:
>> >>> SeaBIOS requires a minimum of 1Meg of ram.  I didn't even know one
>> >>> could request less than 1meg of ram from QEMU.
>> >>
>> >> I'll cook up a QEMU patch to give it at least that much.
>> 
>> > But QEMU may use other firmware/payload than SeaBIOS which might
>> > require less than 1 MB of RAM.
>> 
>> Good point.
>
> I disagree actually. It is not an invalid point, but please optimize
> for the common case and let's deal with microscopic corner cases if
> they actually happen.
>
>
>> Could SeaBIOS fail more cleanly when it detects insufficient RAM?
>
> What would you propose?

Fail POST with panic("Not enough RAM")?

Perfect score if can limit ourselves to just ROM, registers, and
possibly CPU cache, but no RAM, before this check.  It's been done
elsewhere, but it may not be practical for us.

If we can't, we merely reduce the "need this much RAM to avoid silent
failure" limit to something pretty much any conceivable firmware will
require.  QEMU might be more willing to enforce such a low limit.
Making it enforce 1MiB will be a hard sell, I'm afraid...