[coreboot] [Bochs-developers] Has anyone used a real BIOS image?

Carl-Daniel Hailfinger c-d.hailfinger.devel.2006 at gmx.net
Mon Apr 6 01:12:23 CEST 2009

Hi Mark,

you have some coreboot questions in the mail below. I'm quoting it in
full and adding the coreboot mailing list to CC.

On 06.04.2009 00:15, Mark Marshall wrote:
> For various reasons (mainly out of curiosity) I've been spending a while 
> to see if I can get Bochs to boot (and maybe then run) with a real 
> (unaltered) BIOS.  Has anyone done this in the past?  What BIOS did they 
> use?  How much did they need to tweak things to get it to work?  (I need 
> PCI for this to be interesting to me).
> I've been playing around trying to get an ASUS P2B to boot.  I've got as 
> far as it getting the graphics up and running (by mapping in the VGA 
> cards BIOS) but it seems to hang while it's running some sort of test on 
> the PIT.  The POST code has counted up from 0x05 to 0x14 but then hangs. 
>   (The Award docs I've found on the net all say that 0x14 means it's 
> doing something with the PIT).

Are you trying to get an Asus P2B (hardware) to work or do you want to
execute the P2B BIOS in Bochs? Given your first sentence, it seems you
want the latter.

> To get this far I've had to tweak a few things, mainly to move the PCI 
> hardware up to 440BX standard.  I've also created a skeleton SuperIO.
> This is the sort of generation of hardware that I wanted to go for, but 
> I had no real requirements.  It seemed that the P2B was well understood 
> (It's the generation of Intel chip-set that seems to be best documented).
> I had to add a little more support to the SMBus stuff, but I still don't 
> really know what values I should return to mean what - there's a good 
> chance I've told the BIOS that I have gigs of RAM.
> Has anyone ever used a coreboot BIOS with Bochs?  Does this work?  Do 
> the coreboot guys even use Bochs to get things going (if they don't yet, 
> then I suspect that they would really appreciate Bochs emulation being 
> improved to the point where this is possible).

The standard coreboot target for development without hardware is Qemu. I
believe coreboot runs in Bochs as well, but it's been a long time since
I tried and I don't really remember the results.

> I first got interested in Bochs because I've been writing the VGA BIOS 
> for the OGD1 project.  For this I wanted a development cycle that didn't 
> involve re-flashing a board and then power-cycling a PC.  Bochs has been 
> great for this, so thanks.
> MM
> PS.
> I will at some point have a few patches to send up-stream, but I have 
> slightly large questions about the configuration mechanism used in Bochs 
> at the moment.  I'd like to be able to give it configuration files that 
> matched different _real_ hardware - I'm not convinced that we can do 
> that at the moment. (A P2B, a A7N8x, etc.).



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