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

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

On Thu, Nov 21, 2013 at 02:39:10PM +0100, Igor Mammedov wrote:
> 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.

So at the moment there's no negotiation, is there?


> > 
> > > ---
> > > 
> > > 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