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Re: [Qemu-devel] [PATCH RFC 0/3] seabios: move acpi table formatting out
From: |
Michael S. Tsirkin |
Subject: |
Re: [Qemu-devel] [PATCH RFC 0/3] seabios: move acpi table formatting out of bios |
Date: |
Tue, 7 May 2013 21:00:48 +0300 |
On Thu, Apr 25, 2013 at 12:02:20PM +0300, 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.
After some thought, there are two additional
options worth considering, in that they simplify
bios code somewhat:
- bios could get size from qemu, allocate a buffer
(e.g. could be one buffer for all tables)
and pass the address to qemu.
qemu does all the patching
- further, qemu could do the copy of tables into
that address directly
thoughts?
> 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
- Re: [Qemu-devel] [PATCH RFC 0/3] seabios: move acpi table formatting out of bios,
Michael S. Tsirkin <=
- Re: [Qemu-devel] [PATCH RFC 0/3] seabios: move acpi table formatting out of bios, Kevin O'Connor, 2013/05/07
- Re: [Qemu-devel] [PATCH RFC 0/3] seabios: move acpi table formatting out of bios, Gleb Natapov, 2013/05/08
- Re: [Qemu-devel] [PATCH RFC 0/3] seabios: move acpi table formatting out of bios, Michael S. Tsirkin, 2013/05/08
- Re: [Qemu-devel] [PATCH RFC 0/3] seabios: move acpi table formatting out of bios, Gleb Natapov, 2013/05/08
- Re: [Qemu-devel] [PATCH RFC 0/3] seabios: move acpi table formatting out of bios, Michael S. Tsirkin, 2013/05/08
- Re: [Qemu-devel] [PATCH RFC 0/3] seabios: move acpi table formatting out of bios, Gleb Natapov, 2013/05/08
- Re: [Qemu-devel] [PATCH RFC 0/3] seabios: move acpi table formatting out of bios, Michael S. Tsirkin, 2013/05/08
- Re: [Qemu-devel] [PATCH RFC 0/3] seabios: move acpi table formatting out of bios, Gleb Natapov, 2013/05/08
- Re: [Qemu-devel] [PATCH RFC 0/3] seabios: move acpi table formatting out of bios, Michael S. Tsirkin, 2013/05/08
- Re: [Qemu-devel] [PATCH RFC 0/3] seabios: move acpi table formatting out of bios, Gleb Natapov, 2013/05/08