[Qemu-devel] [RFC PATCH v2 00/12] Guest startup time optimization

[Chao Peng]

This patchset is trying to optimize guest startup time by disabling
or simplifying some features in QEMU. The version 1 can be found at:
https://lists.nongnu.org/archive/html/qemu-devel/2016-06/msg04842.html

Unlike version 1, this version optimizes Q35 directly instead of
introducing a totally new platform. But we still keep the design of
skipping firmware as till now we don't have good idea to optimize
firmware to get the comparable boot time.

The patchset is against commit 5f0e775 (Update version for v2.7.0-rc3
release) on master branch.

Basically this patchset introduces several switches to qemu comandline
so that several features can be turned off in some use cases. The
default behavior will not change in case no switches are provided.

Performance data:
feature(switches)       time saved in guest
-nosmbus                4ms
-nosata                 6ms
-nopic                  2ms
-nopit                  5ms
-static-prt             8ms
-nofw                   62ms

Thanks,
Chao

Chao Peng (9):
  pc: make smbus configurable
  pc: make sata configurable
  pc: make pic configurable
  pc: make pit configurable
  acpi: build static _PRT
  ich9: enable pm registers when there is no firmware
  q35: initialize MMCFG base when there is no firmware
  pc: support direct loading protected/long mode kernel
  pc: skip firmware

Haozhong Zhang (3):
  acpi: expose data structurs and functions of BIOS linker loader
  acpi: expose acpi_checksum()
  acpi: patch guest ACPI when there is no firmware

 hw/acpi/bios-linker-loader.c         |  83 +---------
 hw/acpi/core.c                       |   2 +-
 hw/acpi/nvdimm.c                     |   6 +-
 hw/i386/Makefile.objs                |   2 +-
 hw/i386/acpi-build-nofw.c            | 295 ++++++++++++++++++++++++++++++++++
 hw/i386/acpi-build.c                 | 102 +++++++-----
 hw/i386/acpi-build.h                 |   5 +
 hw/i386/pc.c                         | 301 +++++++++++++++++++++++++++++++----
 hw/i386/pc_piix.c                    |   2 +-
 hw/i386/pc_q35.c                     |  60 ++++---
 hw/isa/lpc_ich9.c                    |  12 +-
 hw/pci-host/q35.c                    |  15 +-
 include/hw/acpi/acpi.h               |   2 +
 include/hw/acpi/bios-linker-loader.h |  85 ++++++++++
 include/hw/i386/pc.h                 |  16 +-
 15 files changed, 800 insertions(+), 188 deletions(-)
 create mode 100644 hw/i386/acpi-build-nofw.c

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1.8.3.1