[SeaBIOS] [PATCH 2/2] accept MADT over fw_cfg

[Michael S. Tsirkin]

On Thu, Mar 21, 2013 at 08:04:38PM -0400, Kevin O'Connor wrote:
> On Thu, Mar 21, 2013 at 03:26:26PM +0200, Michael S. Tsirkin wrote:
> > On Thu, Mar 21, 2013 at 01:14:38PM +0000, David Woodhouse wrote:
> > > On Thu, 2013-03-21 at 15:12 +0200, Michael S. Tsirkin wrote:
> > > > Anyway, I am not against such runtime flags.
> > > > 
> > > > If we add to this an option to build a minimal BIOS
> > > > that only works with the new QEMU, do we have a deal?
> > > 
> > > Yeah, definitely. The code for SeaBIOS to build its own should certainly
> > > be optional. It should be possible to build a minimal SeaBIOS which
> > > *can't*.
> 
> Agreed.
> 
> > Okay that's exactly what me and Laszlo are working on.
> > We want to add a special way to build qemu and seabios
> > such that they work with tables in qemu, then add
> > runtime detection on top.
> > 
> > The advantage is that we can make progress
> > without keeping lots of patches out of tree.
> > Unless of course Kevin nacks this all ...
> 
> I think we need to have a plan for what the final interface will look
> like.
> 
> Right now, we can't change QEMU to pass tables via the existing fw_cfg
> entries unless we upgrade SeaBIOS in QEMU first (otherwise things like
> duplicate MADT entries occur).  If we're going to upgrade SeaBIOS in
> QEMU, we really want that upgrade to be the final version.  We don't
> want to have to bump the seabios rev in qemu multiple times in
> lock-step with the changes.
> 
> So, I see two ways to do this:
> 
> 1 - update SeaBIOS with a patch series that makes it capable of
> handling all tables via existing and new fw_cfg entries (including
> flags to disable all internal tables), update QEMU to use that SeaBIOS
> rev, and then apply a patch series to QEMU that has it create all the
> tables (with the final patch flagging to seabios that it should no
> longer create any internal tables).
> 
> or, 2 - apply a patch series to QEMU that has it create all the tables
> via new fw_cfg entries, then apply a patch series to seabios that
> updates it to use the new fw_cfg entries instead of its existing
> internal tables, and then apply that new rev of seabios to qemu.
> 
> Were you proposing one of the above paths, or did you have something
> else in mind?
> 
> -Kevin

Exactly, I'm proposing 1, on top of this, a set of compile-time flags to
optionally stip unused tables from the bios binary.

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MST