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

[Gerd Hoffmann]

>> As this is quite a bunch of work I would tend to avoid a flag day like
>> this so we can switch over tables one by one without building up big
>> patch queues.
> 
> True.  I'm certainly open to ideas.
> 
> In practice, one never wants to mix QEMU generated ACPI tables with
> SeaBIOS generated ACPI tables.

Yea, that would only be the case for the transition phase.

But maybe it isn't the best idea to attempt doing the switch without
breaking anything along the way.  We could use the existing logic vs.
"all tables from qemu" depending on a fw_cfg file being present or not
as you've suggested.  Make that runtime-switchable in qemu for easy testing.

Then start the qemu-provided tables with the minimal feature set needed
to boot up (i.e. no cpu hotplug, no pci hotplug, no ssdt patching,
static smbios, ...).  That could be easy enougth to be added in a single
patch series.

ovmf + coreboot can be updated to also use the qemu tables at this point.

Once we are there start generating/patching tables on the qemu side to
get back to feature parity with current seabios-provided tables.  Can
easily be done incrementally, even without having to patch seabios /
ovmf / coreboot for each step (well, in theory, in practice there are
probably cases where we have to fixup something overseen earlier ...).

Sounds sane?

cheers,
  Gerd