Re: [SeaBIOS] [PATCH RFC 0/3] seabios: move acpi table formatting out of bios

[Michael S. Tsirkin]

On Thu, Apr 25, 2013 at 08:19:48PM +0200, Fred . wrote:
> With ACPI moved out of SeaBIOS to QEMU, how will ACPI work when using SeaBIOS
> without QEMU?
>
> Like if using SeaBIOS with Boch, KVM or Coreboot?

KVM merged with QEMU, so it will use romfiles too.
Others will have two options:

- keep using that tables in seabios. With time we will be able
  to drop qemu-specific stuff in the tables which should make life
  easier for Bochs/coreboot.
- add ACPI through romfiles like QEMU will do.

Which one will be chosen will be up to relevant projects,
but note how they benefit in any case.
> On Thu, Apr 25, 2013 at 11:02 AM, Michael S. Tsirkin  wrote:
> Untested yet, but I thought I'd share the
> BIOS bits so we can agree on direction.
>
> In particular check out ROM sizes:
> - Before patchset with DSDT enabled
>     Total size: 127880  Fixed: 59060  Free: 3192 (used 97.6% of 128KiB rom)
> - Before patchset with DSDT disabled
>     Total size: 122844  Fixed: 58884  Free: 8228 (used 93.7% of 128KiB rom)
> - After patchset:
>     Total size: 128776  Fixed: 59100  Free: 2296 (used 98.2% of 128KiB rom)
> - Legacy disabled at build time:
>     Total size: 119836  Fixed: 58996  Free: 11236 (used 91.4% of 128KiB
> rom)
>
> As can be seen from this, most size savings come
> from dropping DSDT, but we do save a bit by removing
> other tables. Of course the real reason to move tables to QEMU
> is so that ACPI can better match hardware.
>
> This patchset adds an option to move all code for formatting acpi tables
> out of BIOS. With this, QEMU has full control over the table layout.
> All tables are loaded from the new "/etc/acpi/" directory.
> Any entries in this directory cause BIOS to disable
> ACPI table generation completely.
> A generic linker script, controlled by QEMU, is
> loaded from "/etc/linker-script". It is used to
> patch in table pointers and checksums.
>
> BIOS still has limited ability to parse the tables,
> for the following purposes:
>         - locate resume vector
>         - allocate RSDP in FSEG
>         - allocate FACS at an aligned address
>
> --
> MST
>
>
> Michael S. Tsirkin (3):
>   linker: utility to patch in-memory ROM files
>   acpi: load and link tables from /etc/acpi/
>   acpi: add an option to disable builtin tables
>
>  Makefile     |  2 +-
>  src/Kconfig  | 12 +++++++-
>  src/acpi.c   | 67 +++++++++++++++++++++++++++++++++++++++++++-
>  src/linker.c | 90
> ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
>  src/linker.h | 50 +++++++++++++++++++++++++++++++++
>  src/util.h   |  1 +
>  6 files changed, 219 insertions(+), 3 deletions(-)
>  create mode 100644 src/linker.c
>  create mode 100644 src/linker.h
>
> --
> MST
>
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[Qemu-devel] [PATCH RFC 0/3] seabios: move acpi table formatting out of bios

[Kevin O'Connor]

On Fri, Apr 26, 2013 at 12:11:24AM +0300, Michael S. Tsirkin wrote:
> On Thu, Apr 25, 2013 at 08:19:48PM +0200, Fred . wrote:
> > With ACPI moved out of SeaBIOS to QEMU, how will ACPI work when using SeaBIOS
> > without QEMU?
> >
> > Like if using SeaBIOS with Boch, KVM or Coreboot?
>
> KVM merged with QEMU, so it will use romfiles too.
> Others will have two options:
> keep using that tables in seabios. With time we will be able
> to drop qemu-specific stuff in the tables which should make life
> easier for Bochs/coreboot.

FYI - coreboot does not and never has used the acpi tables in seabios.

-Kevin