Merge remote-tracking branch 'remotes/ehabkost/tags/machine-next-pull-request' into staging

Machine queue post-3.1.0 (including 4.0 machine-types)

Features:
* Add 4.0 machine-types to q35/440fx/arm/spapr (Alex Williamson)

Documentation:
* Document vCPU hotplug procedure (Kashyap Chamarthy)
* Deprecate `cpu-add` monitor commands (Kashyap Chamarthy)

Bug fixes:
* A small sun4v_rtc_write() tracing fix that fell through the cracks
  (Eduardo Habkost)
* Validation of "host-nodes" option on memory backends (Eduardo Habkost)
* memory-device fixes and cleanups (David Hildenbrand)

Cleanups:
* Machine-type code cleanup (remove unnecessary instance_init functions)
  (Eduardo Habkost)
* qdev, qom, and global property code cleanups (Marc-André Lureau)
* PCMachineState field renames (Corey Minyard)
* numa: Match struct to typedef name (Eric Blake)
* hostmem-file: remove object id from pmem error message (Zhang Yi)

# gpg: Signature made Tue 11 Dec 2018 17:58:03 GMT
# gpg:                using RSA key 2807936F984DC5A6
# gpg: Good signature from "Eduardo Habkost <ehabkost@redhat.com>"
# Primary key fingerprint: 5A32 2FD5 ABC4 D3DB ACCF  D1AA 2807 936F 984D C5A6

* remotes/ehabkost/tags/machine-next-pull-request: (24 commits)
  qom: remove unimplemented class_finalize
  qdev: move qdev_prop_register_global_list() to tests
  accel: register global_props like machine globals
  qom: make user_creatable_complete() specific to UserCreatable
  qom: make interface types abstract
  tests: qdev_prop_check_globals() doesn't return "all_used"
  pc: Use default_machine_opts to set suppress_vmdesc
  spapr: Delete instance_options functions
  spapr: Use default_machine_opts to set suppress_vmdesc
  spapr: Use default_machine_opts to set use_hotplug_event_source
  virt: Eliminate separate instance_init functions
  q35/440fx/arm/spapr: Add QEMU 4.0 machine type
  hostmem: Validate host-nodes before setting bitmap
  numa: Match struct to typedef name
  i386: Rename bools in PCMachineState to end in _enabled
  move ObjectClass to typedefs.h
  memory-device: avoid overflows on very huge devices
  memory-device: use QEMU_IS_ALIGNED
  range: pass const pointer where possible
  Deprecate HMP `cpu-add`
  ...

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

1 files changed, 142 insertions, 0 deletions

diff --git a/docs/cpu-hotplug.rst b/docs/cpu-hotplug.rst
new file mode 100644
index 0000000000..1c268e00b4
--- /dev/null
+++ b/docs/cpu-hotplug.rst
@@ -0,0 +1,142 @@
+===================
+Virtual CPU hotplug
+===================
+
+A complete example of vCPU hotplug (and hot-unplug) using QMP
+``device_add`` and ``device_del``.
+
+vCPU hotplug
+------------
+
+(1) Launch QEMU as follows (note that the "maxcpus" is mandatory to
+    allow vCPU hotplug)::
+
+      $ qemu-system-x86_64 -display none -no-user-config -m 2048 \
+          -nodefaults -monitor stdio -machine pc,accel=kvm,usb=off \
+          -smp 1,maxcpus=2 -cpu IvyBridge-IBRS \
+          -qmp unix:/tmp/qmp-sock,server,nowait
+
+(2) Run 'qmp-shell' (located in the source tree, under: "scripts/qmp/)
+    to connect to the just-launched QEMU::
+
+      $> ./qmp-shell -p -v /tmp/qmp-sock
+      [...]
+      (QEMU)
+
+(3) Find out which CPU types could be plugged, and into which sockets::
+
+      (QEMU) query-hotpluggable-cpus
+      {
+          "execute": "query-hotpluggable-cpus",
+          "arguments": {}
+      }
+      {
+          "return": [
+              {
+                  "type": "IvyBridge-IBRS-x86_64-cpu",
+                  "vcpus-count": 1,
+                  "props": {
+                      "socket-id": 1,
+                      "core-id": 0,
+                      "thread-id": 0
+                  }
+              },
+              {
+                  "qom-path": "/machine/unattached/device[0]",
+                  "type": "IvyBridge-IBRS-x86_64-cpu",
+                  "vcpus-count": 1,
+                  "props": {
+                      "socket-id": 0,
+                      "core-id": 0,
+                      "thread-id": 0
+                  }
+              }
+          ]
+      }
+      (QEMU)
+
+(4) The ``query-hotpluggable-cpus`` command returns an object for CPUs
+    that are present (containing a "qom-path" member) or which may be
+    hot-plugged (no "qom-path" member).  From its output in step (3), we
+    can see that ``IvyBridge-IBRS-x86_64-cpu`` is present in socket 0,
+    while hot-plugging a CPU into socket 1 requires passing the listed
+    properties to QMP ``device_add``:
+
+      (QEMU) device_add id=cpu-2 driver=IvyBridge-IBRS-x86_64-cpu socket-id=1 core-id=0 thread-id=0
+      {
+          "execute": "device_add",
+          "arguments": {
+              "socket-id": 1,
+              "driver": "IvyBridge-IBRS-x86_64-cpu",
+              "id": "cpu-2",
+              "core-id": 0,
+              "thread-id": 0
+          }
+      }
+      {
+          "return": {}
+      }
+      (QEMU)
+
+(5) Optionally, run QMP `query-cpus-fast` for some details about the
+    vCPUs::
+
+      (QEMU) query-cpus-fast
+      {
+          "execute": "query-cpus-fast",
+          "arguments": {}
+      }
+      {
+          "return": [
+              {
+                  "qom-path": "/machine/unattached/device[0]",
+                  "target": "x86_64",
+                  "thread-id": 11534,
+                  "cpu-index": 0,
+                  "props": {
+                      "socket-id": 0,
+                      "core-id": 0,
+                      "thread-id": 0
+                  },
+                  "arch": "x86"
+              },
+              {
+                  "qom-path": "/machine/peripheral/cpu-2",
+                  "target": "x86_64",
+                  "thread-id": 12106,
+                  "cpu-index": 1,
+                  "props": {
+                      "socket-id": 1,
+                      "core-id": 0,
+                      "thread-id": 0
+                  },
+                  "arch": "x86"
+              }
+          ]
+      }
+      (QEMU)
+
+vCPU hot-unplug
+---------------
+
+From the 'qmp-shell', invoke the QMP ``device_del`` command::
+
+      (QEMU) device_del id=cpu-2
+      {
+          "execute": "device_del",
+          "arguments": {
+              "id": "cpu-2"
+          }
+      }
+      {
+          "return": {}
+      }
+      (QEMU)
+
+.. note::
+    vCPU hot-unplug requires guest cooperation; so the ``device_del``
+    command above does not guarantee vCPU removal -- it's a "request to
+    unplug".  At this point, the guest will get a System Control
+    Interupt (SCI) and calls the ACPI handler for the affected vCPU
+    device.  Then the guest kernel will bring the vCPU offline and tell
+    QEMU to unplug it.