Re: [Qemu-devel] Re: [PATCH 1/4] Add GPL bios as a submodule

[ron minnich]

On Sun, May 17, 2009 at 4:22 PM, Anthony Liguori <address@hidden> wrote:

> I find this very unlikely.  I don't think coreboot bothers with things like
> building ACPI tables.  Why would it have to when it has a full Linux
> environment?

We did not used to. But it's been a long time since we did just linux
in flash. Now there are lots of other combinations:
coreboot+seabios
coreboot+seabios+gpxe
coreboot+tiano
and on and on ...

Many of these combinations require ACPI and/or SMM. Sad news: vendor
hardware is nowadays *more*, not *less*, dependent on SMM -- very few
modern Intel
chipsets can function without a working SMM layer -- or so the people
with the docs tell me. So SMM and ACPI, both huge security issues in
their
own right, are almost impossible to eliminate nowadays. And, good fun,
some new chips now require that microcode be patched *before* memory
is even turned out. Good fun. No more patching microcode from Linux!

So coreboot supports SMM&ACPI where they are needed. SMM is mostly
restricted to Intel chips for now.

coreboot also supports tiano, But oh, the irony!: Tiano was billed as
a way to an "open source" bios, in competition with coreboot, but you
really can't build a completely open source BIOS with Tiano alone: you
need to have coreboot to turn on the hardware because you need chipset
stuff that only comes from vendors as a binary blob. So, again, AFAIK,
nobody is really bothering to do much with Tiano core. Tiano is at
most half a BIOS or less. The only fully open source BIOS stack you
can get with Tiano is going to be one that includes coreboot.

To pile on the funny bits, vendors, after telling us for 10 years that
linux-in-flash was a stupid idea, are buying into it in a big way. At
the same time coreboot is supporting more traditional models, some
BIOS vendor are jumping on the Linux-in-FLASH bandwagon. Now wait,
whose side are we on anyway?

> It's a neat project and I think it's valuable to make it more easily used in
> QEMU, but I don't think it can replace our existing BIOS.  I also don't
> think that that's its general mission statement either.  I think its primary
> purpose is to eliminate all the legacy firmware junk and provide the
> quickest and most featureful environment for large clusters.

I think it can replace your existing BIOS. I would not have said that
one year ago. Nowadays, coreboot+seabios can even boot/install xp,
vista, and windows 7. I have now got systems that boot anything I've
tried that used to use a traditional BIOS. These guys:
http://xfc.xfce.org/index.html are using coreboot for a build-bot
because the BIOS that came with the board did not even work; coreboot
got them going.

BTW, thanks for qemu. I do most of my initial coreboot testing on
qemu. It's really been a lifesaver. Conversely, qemu (and kvm for that
matter) users who want a fast booting bios that stays out of their way
can do well with coreboot. There are a lot of people besides me using
coreboot+qemu. Qemu is a very fine piece of work!

ron