Re: [coreboot] [Qemu-devel] Release plan for 0.12.0

[Patrick Georgi <patrick@georgi-clan.de>]

Am Samstag, den 03.10.2009, 14:49 -0700 schrieb Jordan Justen:
> On Sat, Oct 3, 2009 at 10:30, Peter Stuge <peter@stuge.se> wrote:
> > Jordan Justen wrote:
> >> Anyway, it sounds like a useful project might be to develop a UEFI
> >> coreboot payload based on the tianocore.org code.
> >
> > I believe it might have been done already.
> >
> > http://www.coreboot.org/File:Tianocoreboot.png
> 
> That screenshot mentions DUET which is the tianocore.org UEFI emulator
> that boots on top of a legacy BIOS.  But, it's unclear if it was just
> DUET, or something based modified specifically for coreboot based on
> DUET.
Modified: The 16bit loader stub was dropped and replaced by 32bit C code
that did mostly the same (pushing code to the right address, jump to the
real entry point, as determined by some PE data structures).
With some minor modification to Duet it's even possible to remove the
470k limit Duet suffers from, by moving the data chunk to >1MB.

Interaction with BIOS seems to be restricted to expecting the right
tables (ACPI, MP table, SMBIOS stuff), which coreboot can provide.

> be able to boot UEFI OS's at this time.)  However, we thought a
> project such as OVMF was a more direct approach to achieve UEFI
> compatibility for QEMU.
With coreboot, seabios and Duet, it should be reasonably simple to
provide a single BIOS image that selects (based on nvram - ie.
configuration) which interface to provide: PCBIOS or UEFI.

If that is just as simple with OVMF, and easier to maintain, then it's
hard to argue with that.


Patrick