Re: [Qemu-devel] [Linaro-acpi] [RFC PATCH 0/7] hw/arm/virt: Dynamic ACPI v5.1 table generation

[Paolo Bonzini]

On 12/11/2014 13:04, Mark Rutland wrote:
>> > SeaBIOS fishes out information from fw_cfg, and puts it in low memory.
>> > On ARM you could use DT binary blobs instead of fw_cfg, as proposed
>> > already (I don't remember if it was in this thread or IRC).  Then if you
>> > want to go !UEFI you can extract the tables from those binary blobs.
> This sounds broken. I am very much not a fan of shoving binary blobs
> into DT to workaround a shoddy boot interface.

We tried spec-ing everything and building the tables in the firmware on
x86.  You really do not want to do that; it's painful to have to update
firmware in lockstep with QEMU, and when you add the next feature it
always seems like you got the bindings wrong.

And we only had one client (SeaBIOS) while you will have at least two
(TianoCore and Linux, presumably? or is Huawei targeting OSv only?).

What we do now is we have two blobs, one with the ACPI tables and one
that tells the firmware how to relocate pointers from one table to
another.  It's been working very well for both SeaBIOS and OVMF.

Paolo