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
