[SeaBIOS] [PATCH RFC 00/13] qemu: generate acpi tables for the guest
anthony at codemonkey.ws
Mon May 13 22:38:51 CEST 2013
"Michael S. Tsirkin" <mst at redhat.com> writes:
> This patchset moves all generation of ACPI tables
> from guest BIOS to the hypervisor.
> Although ACPI tables come from a system BIOS on real hw,
> it makes sense that the ACPI tables are coupled with the
> virtual machine, since they have to abstract the x86 machine to
> the OS's.
> Several future developments that this will enable:
> - make it easier to use alternative firmware:
> any firmware can just load the ACPI tables from QEMU.
> case in point OVMF.
UEFI obviously can create ACPI tables already so I don't think this is a
You could use this argument to say that QEMU should implement int13 or
> - make it easier to add more chipsets without bumping
> into fw_cfg boundaries.
But then you're just introducing a different boundary (the ACPI tables).
fw_cfg is a cross-platform interface so it makes a lot more sense to add
more features to it to better enumerate the underlying platform.
> - describe a complex configuration
> e.g. a bridged PCI topology to enable
> acpi hotplug of devices behind a PCI bridge,
> or for multi-root topology.
This has strong analogies to generating device trees and is also a good
reason why exposing this information via a common interface (fw_cfg)
would be a good idea.
> If you look at the actual code:
> i386: imports ACPI table generation code from seabios
> you will see that it's more complex than it
> needs to be, with lots of low level casts
> and similar tricks.
> There's also a bit of duplication where we
> already declare similar acpi structures in qemu.
> This is the result of code being a direct port from seabios.
> Laszlo's patch (build ACPI MADT (APIC) for fw_cfg)
> shows how this will be cleaned up by follow-up work.
> I think it's best to do it in this order: port
> code directly, and apply cleanups and reduce duplication
> that results, on top.
> This way it's much easier to see that we don't introduce
> In particular, for a simple VM with piix,
> I booted a guest on qemu with and without the
> change, and verified that ACPI tables are
> unchanged except for trivial pointer address changes.
> Such binary compatibility makes it easier to be
> confident that this change won't break things.
> So the idea is Laszlo's patchset (patches 2-7) will be rebased on top of
> this patchset, this way we'll get small cleanup changes, where each step
> is easy to verify as not changing anything from Guest POV.
> One issue this patchset creates is cross-version migration.
> Specifically migration to qemu 1.5 will not work
> if it happens while bios is accessing fw_cfg when we
> This is a general problem of the fw_cfg implementation,
> I plan to extend fw_cfg implementation to address this.
> I plan to test q35 and numa setups before I submit
> this for inclusion, in a similar way.
> git trees, for those interested in testing this:
> git://git.kernel.org/pub/scm/virt/kvm/mst/qemu.git acpi
> git://git.kernel.org/pub/scm/virt/kvm/mst/seabios.git acpi
> bios patchset will be posted tomorrow (need to clean up
> the commit log a bit).
I don't think it's a good idea to move BIOS functionality in QEMU.
We don't frequently add firmware or chipsets so it seems like we're
optimizing for an uncommon scenario here.
> Laszlo Ersek (1):
> refer to FWCfgState explicitly
> Michael S. Tsirkin (12):
> apic: rename apic specific bitopts
> hw/i386/pc.c: move IO_APIC_DEFAULT_ADDRESS to include/hw/i386/apic.h
> fw_cfg: move typedef to qemu/typedefs.h
> i386: add ACPI table files from seabios
> acpi: add rules to compile ASL source
> acpi: pre-compiled ASL files
> range: add Range structure
> i386: add bios linker/loader
> i386: generate pc guest info
> pc: pass PCI hole ranges to Guests
> i386: ACPI table generation code from seabios
> pc: reuse guest info for legacy fw cfg
> configure | 9 +-
> hw/acpi/ich9.c | 7 +-
> hw/acpi/piix4.c | 44 +-
> hw/core/loader.c | 2 +-
> hw/i386/Makefile.objs | 27 +
> hw/i386/acpi-build.c | 685 ++++
> hw/i386/acpi-dsdt-cpu-hotplug.dsl | 93 +
> hw/i386/acpi-dsdt-dbug.dsl | 41 +
> hw/i386/acpi-dsdt-hpet.dsl | 51 +
> hw/i386/acpi-dsdt-isa.dsl | 117 +
> hw/i386/acpi-dsdt-pci-crs.dsl | 105 +
> hw/i386/acpi-dsdt.dsl | 343 ++
> hw/i386/acpi-dsdt.hex.generated | 4409 ++++++++++++++++++++
> hw/i386/bios-linker-loader.c | 155 +
> hw/i386/multiboot.c | 2 +-
> hw/i386/multiboot.h | 4 +-
> hw/i386/pc.c | 159 +-
> hw/i386/pc_piix.c | 28 +-
> hw/i386/pc_q35.c | 14 +-
> hw/i386/q35-acpi-dsdt.dsl | 452 +++
> hw/i386/q35-acpi-dsdt.hex.generated | 7346 ++++++++++++++++++++++++++++++++++
> hw/i386/ssdt-misc.dsl | 73 +
> hw/i386/ssdt-misc.hex.generated | 190 +
> hw/i386/ssdt-pcihp.dsl | 51 +
> hw/i386/ssdt-pcihp.hex.generated | 108 +
> hw/i386/ssdt-proc.dsl | 63 +
> hw/i386/ssdt-proc.hex.generated | 134 +
> hw/intc/apic.c | 42 +-
> hw/isa/lpc_ich9.c | 11 +-
> hw/mips/mips_malta.c | 2 +-
> hw/pci-host/q35.c | 5 +
> hw/sparc/sun4m.c | 6 +-
> hw/sparc64/sun4u.c | 2 +-
> include/hw/acpi/ich9.h | 2 +-
> include/hw/i386/acpi-build.h | 9 +
> include/hw/i386/apic.h | 2 +
> include/hw/i386/bios-linker-loader.h | 26 +
> include/hw/i386/ich9.h | 3 +-
> include/hw/i386/pc.h | 67 +-
> include/hw/loader.h | 3 +-
> include/hw/nvram/fw_cfg.h | 2 +-
> include/hw/pci-host/q35.h | 2 +
> include/qemu/range.h | 22 +
> include/qemu/typedefs.h | 2 +
> scripts/acpi_extract.py | 362 ++
> scripts/acpi_extract_preprocess.py | 52 +
> scripts/update-acpi.sh | 4 +
> 47 files changed, 15248 insertions(+), 90 deletions(-)
> create mode 100644 hw/i386/acpi-build.c
> create mode 100644 hw/i386/acpi-dsdt-cpu-hotplug.dsl
> create mode 100644 hw/i386/acpi-dsdt-dbug.dsl
> create mode 100644 hw/i386/acpi-dsdt-hpet.dsl
> create mode 100644 hw/i386/acpi-dsdt-isa.dsl
> create mode 100644 hw/i386/acpi-dsdt-pci-crs.dsl
> create mode 100644 hw/i386/acpi-dsdt.dsl
> create mode 100644 hw/i386/acpi-dsdt.hex.generated
> create mode 100644 hw/i386/bios-linker-loader.c
> create mode 100644 hw/i386/q35-acpi-dsdt.dsl
> create mode 100644 hw/i386/q35-acpi-dsdt.hex.generated
> create mode 100644 hw/i386/ssdt-misc.dsl
> create mode 100644 hw/i386/ssdt-misc.hex.generated
> create mode 100644 hw/i386/ssdt-pcihp.dsl
> create mode 100644 hw/i386/ssdt-pcihp.hex.generated
> create mode 100644 hw/i386/ssdt-proc.dsl
> create mode 100644 hw/i386/ssdt-proc.hex.generated
> create mode 100644 include/hw/i386/acpi-build.h
> create mode 100644 include/hw/i386/bios-linker-loader.h
> create mode 100755 scripts/acpi_extract.py
> create mode 100755 scripts/acpi_extract_preprocess.py
> create mode 100644 scripts/update-acpi.sh
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