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

[Igor Mammedov <imammedo@redhat.com>]

On Thu, 21 Nov 2013 08:20:56 +0200
"Michael S. Tsirkin" <mst@redhat.com> wrote:

> 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?
version negotiation between ASL and hardware could be used to that effect.

QEMU could start with present but disabled memory hotplug and if
QEMU and BIOS ASL could come in agreement that both support it in
compatible way, it could be enabled.

> 
> > ---
> > 
> > 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