Re: [Qemu-devel] [PATCH 00/27 RFC v7] ACPI memory hotplug

["Michael S. Tsirkin" <mst@redhat.com>]

On Thu, Nov 21, 2013 at 03:38:21AM +0100, Igor Mammedov wrote:
> ---
> What's new since v6:
> 
> * DIMM device is split to backend and frontend. Therefore following
>   command/options were added for supporting it:
> 
>   For memdev backend:
>       CLI: -memdev-add
>       Monitor/QMP: memdev-add
>           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'
> 
> * Added Q35 support
> * Added support for 32 bit guests
> * build for i386 emulator (not tested)

OK so a large patchset so did not review yet.  One question
due to the dependency on bios honouring etc/reserved-memory-end: is
there some way to detect old BIOS and fail memory hotplug?

> ---
> 
> 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:
> 
>   memdev-add 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
>   start - 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
>  - Windows 2008DCx32
> 
> Known limitations/bugs/TODOs:
>  - only hot-add supported
>  - max number of supported DIMM devices 255 (due to ACPI object name
>    limit), could be increased creating several containers and putting
>    DIMMs there. (exercise for future) 
>  - failed hotplug action consumes 1 slot (device_add doesn't delete
>    device properly if realize failed)
>  - 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
>    start/size is added into the same slot, it refuses to use it insisting
>    on old mapping.
> 
> Series is based on mst's PCI tree and requires following SeaBIOS patch:
>   http://patchwork.ozlabs.org/patch/292614/
>   on top of patches to load ACPI tables from QEMU
>   working SeaBIOS tree for testing is available at:
>     https://github.com/imammedo/seabios/commits/memhp-wip
> 
> QEMU git tree for testing is available at:
>   https://github.com/imammedo/qemu/commits/memory-hotplug-v7
> 
> Example QEMU cmd line:
>   qemu-system-x86_64 -enable-kvm -monitor unix:/tmp/mon,server,nowait \ 
>      -m 4096,slots=4,maxmem=8G -L /custome_seabios guest.img
> 
> PS:
>   Windows guest requires SRAT table for hotplug to work so add extra option:
>    -numa node
>   to QEMU command line.
> 
> 
> Igor Mammedov (26):
>   acpi: factor out common pm_update_sci() into acpi core
>   rename pci_hotplug_fn to hotplug_fn and make it available for other
>     devices
>   pc: add 'etc/reserved-memory-end' fw_cfg interface for SeaBIOS
>   vl: convert -m to qemu_opts_parse()
>   qapi: add SIZE type parser to string_input_visitor
>   get reference to /backend container via qemu_get_backend()
>   add memdev backend infrastructure
>   dimm: map DimmDevice into DimBus provided address space
>   dimm: add busy slot check and slot auto-allocation
>   dimm: add busy address check and address auto-allocation
>   dimm: add hotplug callback to DimmBus
>   acpi: memory hotplug ACPI hardware implementation
>   acpi: initialize memory hotplug ACPI PIIX4 hardware
>   acpi: piix4: add memory-hotplug-io-base property to piix4_pm
>   acpi: ich9: allow guest to clear SCI rised by GPE
>   acpi: initialize memory hotplug ACPI ICH9 hardware
>   acpi: ich9: add memory-hotplug-io-base property to ich9_pm
>   acpi: piix4/ich9: add optional vmstate field for MemHotplugState
>     migration
>   pc: piix: make PCII440FXState type public
>   pc: add memory hotplug 440fx machine
>   pc: add memory hotplug Q35 machine
>   pc: ACPI BIOS: implement memory hotplug interface
>   pc: ACPI BIOS: add ssdt-mem.hex.generated and update
>     ssdt-misc.hex.generated
>   pc: ACPI BIOS: use enum for defining memory affinity flags
>   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.c                 |  275 +++++++++++
>  backends/hostmem_compat_ram.c      |   42 ++
>  default-configs/i386-softmmu.mak   |    1 +
>  default-configs/x86_64-softmmu.mak |    1 +
>  docs/specs/acpi_mem_hotplug.txt    |   38 ++
>  hmp-commands.hx                    |   13 +
>  hw/Makefile.objs                   |    1 +
>  hw/acpi/core.c                     |  189 ++++++++
>  hw/acpi/ich9.c                     |   57 ++-
>  hw/acpi/pcihp.c                    |    6 +-
>  hw/acpi/piix4.c                    |   91 +++--
>  hw/i386/Makefile.objs              |    3 +-
>  hw/i386/acpi-build.c               |   91 ++++-
>  hw/i386/acpi-dsdt.dsl              |    5 +-
>  hw/i386/pc.c                       |   90 ++++-
>  hw/i386/pc_piix.c                  |    7 +-
>  hw/i386/pc_q35.c                   |    4 +
>  hw/i386/q35-acpi-dsdt.dsl          |    5 +-
>  hw/i386/ssdt-mem.dsl               |   75 +++
>  hw/i386/ssdt-mem.hex.generated     |  197 ++++++++
>  hw/i386/ssdt-misc.dsl              |  179 ++++++++
>  hw/i386/ssdt-misc.hex.generated    |  881 +++++++++++++++++++++++++++++++++++-
>  hw/mem/Makefile.objs               |    1 +
>  hw/mem/dimm.c                      |  321 +++++++++++++
>  hw/pci-host/piix.c                 |   36 +-
>  hw/pci-host/q35.c                  |   19 +-
>  hw/pci/pci.c                       |   12 +-
>  hw/pci/pcie.c                      |    7 +-
>  hw/pci/shpc.c                      |    9 +-
>  include/hw/acpi/acpi.h             |   42 ++
>  include/hw/acpi/ich9.h             |    6 +
>  include/hw/acpi/pcihp.h            |    2 +-
>  include/hw/acpi/piix4.h            |    2 +
>  include/hw/i386/pc.h               |   33 ++-
>  include/hw/mem/dimm.h              |   99 ++++
>  include/hw/pci-host/piix.h         |   29 ++
>  include/hw/pci-host/q35.h          |    1 +
>  include/hw/pci/pci.h               |   11 +-
>  include/hw/pci/pci_bus.h           |    2 +-
>  include/hw/qdev-core.h             |    9 +
>  include/sysemu/hostmem.h           |  102 +++++
>  include/sysemu/sysemu.h            |    3 +
>  monitor.c                          |    1 +
>  qapi-schema.json                   |   18 +
>  qapi/string-input-visitor.c        |   18 +
>  qemu-options.hx                    |   16 +-
>  qmp-commands.hx                    |   27 ++
>  ui/console.c                       |    3 +-
>  vl.c                               |   98 ++++-
>  50 files changed, 3040 insertions(+), 140 deletions(-)
>  create mode 100644 backends/hostmem.c
>  create mode 100644 backends/hostmem_compat_ram.c
>  create mode 100644 docs/specs/acpi_mem_hotplug.txt
>  create mode 100644 hw/i386/ssdt-mem.dsl
>  create mode 100644 hw/i386/ssdt-mem.hex.generated
>  create mode 100644 hw/mem/Makefile.objs
>  create mode 100644 hw/mem/dimm.c
>  create mode 100644 include/hw/mem/dimm.h
>  create mode 100644 include/hw/pci-host/piix.h
>  create mode 100644 include/sysemu/hostmem.h