[Qemu-devel] [PATCH v2 00/31] pc: ACPI memory hotplug

[Igor Mammedov <imammedo@redhat.com>]

What's new since v8:

 * rebased on top of Marcel's QOMyfing machine work
    depends on patch from qom-next:
     "machine: Conversion of QEMUMachineInitArgs to MachineState"
 * fixed QEMU abort if it's running in daemonized mode
 * fixed leak in memdev backend
 * introduced custom PCMachine
 * DIMM devices are now bus-less and use bus-less hotplug method
 * DIMMDevice: renamed property/field 'start' to 'addr'
 * ACPI tables:
   * avoid punching hotples in PCI CRS by placing
     MEMORY_HOPTLUG_DEVICE on PCI0 bus
 * incorporated most of comments/fixes from reviewers

What's new since v7:

* Per Andreas' suggestion dropped DIMMBus concept.
* Added hotplug binding for bus-less devices
* DIMM device is split to backend and frontend. Therefore following
  command/options were added for supporting it:

  For memory-ram backend:
      CLI: -object-add memory-ram,
          with options: 'id' and 'size'
  For dimm frontend:
      option "size" became readonly, pulling it's size from attached backend
      added option "memdev" for specifying backend by 'id'

* dropped support for 32 bit guests
* failed hotplug action doesn't consume 1 slot anymore
* vaious fixes adressing reviewer's comments most of them in ACPI part
---

This series allows to hotplug 'arbitrary' DIMM devices specifying size,
NUMA node mapping (guest side), slot and address where to map it, at runtime.

Due to ACPI limitation there is need to specify a number of possible
DIMM devices. For this task -m option was extended to support
following format:

  -m [mem=]RamSize[,slots=N,maxmem=M]

To allow memory hotplug user must specify a pair of additional parameters:
    'slots' - number of possible increments
    'maxmem' - max possible total memory size QEMU is allowed to use,
               including RamSize.

minimal monitor command syntax to hotplug DIMM device:

  object_add memory-ram,id=memX,size=1G
  device_add dimm,id=dimmX,memdev=memX

DIMM device provides following properties that could be used with
device_add / -device to alter default behavior:

  id    - unique string identifying device [mandatory]
  slot  - number in range [0-slots) [optional], if not specified
          the first free slot is used
  node  - NUMA node id [optional] (default: 0)
  size  - amount of memory to add, readonly derived from backing memdev
  addr - guest's physical address where to plug DIMM [optional],
          if not specified the first gap in hotplug memory region
          that fits DIMM is used

 -device option could be used for adding potentially hotunplugable DIMMs
and also for specifying hotplugged DIMMs in migration case.

Tested guests:
 - RHEL 6x64
 - Windows 2012DCx64
 - Windows 2008DCx64

Known limitations/bugs/TODOs:
 - hot-remove is not supported, yet
 - max number of supported DIMM devices 256 (due to ACPI object name
   limit), could be increased creating several containers and putting
   DIMMs there. (exercise for future) 
 - e820 table doesn't include DIMM devices added with -device /
   (or after reboot devices added with device_add)
 - Windows 2008 remembers DIMM configuration, so if DIMM with other
   addr/size is added into the same slot, it refuses to use it insisting
   on old mapping.

QEMU git tree for testing is available at:
  https://github.com/imammedo/qemu/commits/memory-hotplug-v9

Example QEMU cmd line:
  qemu-system-x86_64 -enable-kvm -monitor unix:/tmp/mon,server,nowait \ 
     -m 4096,slots=4,maxmem=8G guest.img

PS:
  Windows guest requires SRAT table for hotplug to work so add an extra option:
   -numa node
  to QEMU command line.


Igor Mammedov (30):
  pc: ACPI BIOS: use enum for defining memory affinity flags
  object_add: allow completion handler to get canonical path
  vl.c: daemonize before guest memory allocation
  add memdev backend infrastructure
  vl.c: extend -m option to support options for memory hotplug
  pc: create custom generic PC machine type
  qdev: hotplug for buss-less devices
  qdev: expose DeviceState.hotplugged field as a property
  memory: add memory_region_is_mapped() API
  dimm: do not allow to set already used memdev
  pc: initialize memory hotplug address space
  pc: exit QEMU if number of slots more than supported 256
  pc: add 'etc/reserved-memory-end' fw_cfg interface for SeaBIOS
  pc: add memory hotplug handler to PC_MACHINE
  dimm: add busy address check and address auto-allocation
  dimm: add busy slot check and slot auto-allocation
  acpi: rename cpu_hotplug_defs.h to acpi_defs.h
  acpi: memory hotplug ACPI hardware implementation
  trace: add acpi memory hotplug IO region events
  trace: pc: add DIMM slot & address allocation
  acpi:piix4: allow plug/unlug callbacks handle not only PCI devices
  acpi:piix4: add memory hotplug handling
  pc: ich9 lpc: make it work with global/compat properties
  acpi:ich9: add memory hotplug handling
  pc: migrate piix4 & ich9 MemHotplugState
  pc: add acpi-device link to PCMachineState
  pc: propagate memory hotplug event to ACPI device
  pc: ACPI BIOS: implement memory hotplug interface
  pc: ACPI BIOS: reserve SRAT entry for hotplug mem hole
  pc: ACPI BIOS: make GPE.3 handle memory hotplug event on PIIX and Q35
    machines

Vasilis Liaskovitis (1):
  dimm: implement dimm device abstraction

 backends/Makefile.objs             |    2 +
 backends/hostmem-ram.c             |   54 ++++++++
 backends/hostmem.c                 |  110 ++++++++++++++++
 default-configs/i386-softmmu.mak   |    1 +
 default-configs/x86_64-softmmu.mak |    1 +
 docs/specs/acpi_mem_hotplug.txt    |   44 +++++++
 hw/Makefile.objs                   |    1 +
 hw/acpi/Makefile.objs              |    1 +
 hw/acpi/ich9.c                     |   62 +++++++++
 hw/acpi/memory_hotplug.c           |  187 ++++++++++++++++++++++++++++
 hw/acpi/piix4.c                    |   74 ++++++++++--
 hw/core/qdev.c                     |   30 +++++
 hw/i386/Makefile.objs              |    3 +-
 hw/i386/acpi-build.c               |   72 ++++++++++-
 hw/i386/acpi-dsdt.dsl              |    7 +-
 hw/i386/pc.c                       |  198 +++++++++++++++++++++++++++++-
 hw/i386/pc_piix.c                  |   51 +++++---
 hw/i386/pc_q35.c                   |   25 +++-
 hw/i386/q35-acpi-dsdt.dsl          |    7 +-
 hw/i386/ssdt-mem.dsl               |   77 ++++++++++++
 hw/i386/ssdt-misc.dsl              |  164 ++++++++++++++++++++++++
 hw/isa/lpc_ich9.c                  |   33 +++++-
 hw/mem/Makefile.objs               |    1 +
 hw/mem/dimm.c                      |  240 ++++++++++++++++++++++++++++++++++++
 hw/mips/mips_malta.c               |    2 +-
 include/exec/memory.h              |    8 ++
 include/hw/acpi/acpi.h             |    6 +
 include/hw/acpi/acpi_defs.h        |   57 +++++++++
 include/hw/acpi/cpu_hotplug.h      |    2 +-
 include/hw/acpi/cpu_hotplug_defs.h |   33 -----
 include/hw/acpi/ich9.h             |    4 +
 include/hw/acpi/memory_hotplug.h   |   37 ++++++
 include/hw/boards.h                |   11 ++-
 include/hw/i386/pc.h               |   63 +++++++++-
 include/hw/mem/dimm.h              |   80 ++++++++++++
 include/sysemu/hostmem.h           |   60 +++++++++
 memory.c                           |   15 ++-
 qemu-options.hx                    |    9 +-
 qmp.c                              |   11 ++-
 trace-events                       |   17 +++
 vl.c                               |   64 +++++++++-
 41 files changed, 1820 insertions(+), 104 deletions(-)
 create mode 100644 backends/hostmem-ram.c
 create mode 100644 backends/hostmem.c
 create mode 100644 docs/specs/acpi_mem_hotplug.txt
 create mode 100644 hw/acpi/memory_hotplug.c
 create mode 100644 hw/i386/ssdt-mem.dsl
 create mode 100644 hw/mem/Makefile.objs
 create mode 100644 hw/mem/dimm.c
 create mode 100644 include/hw/acpi/acpi_defs.h
 delete mode 100644 include/hw/acpi/cpu_hotplug_defs.h
 create mode 100644 include/hw/acpi/memory_hotplug.h
 create mode 100644 include/hw/mem/dimm.h
 create mode 100644 include/sysemu/hostmem.h