[Qemu-devel] [PATCH 21/21] QMP: add cpu-add command

[Igor Mammedov <imammedo@redhat.com>]

Adds "cpu-add id=xxx" QMP command.

cpu-add's "id" argument is a CPU number in a range [0..max-cpus)

Example QMP command:
 -> { "execute": "cpu-add", "arguments": { "id": 2 } }
 <- { "return": {} }

Signed-off-by: Igor Mammedov <imammedo@redhat.com>
---
v6:
  * added valid values description to qapi schema
  * split out cpu_hot_add hooks introduction into separate patch
  * split out implementation of cpu_hot_add for target-i386
v5:
  * accept id=[0..max_cpus) range in cpu-add command
v4:
  * merge "qmp: add cpu-add qmp command" & "target-i386: implement CPU hot-add" patches
  * move notifier call to CPUCLass.realize()
  * add hook cpu_hot_add to QEMUMachine
  * make QEMUMachineInitArgs global and keep default cpu_model there

v3:
  * it appears that 'online/offline' in cpu-set are confusing people
    with what command actually does and users might have to distinguish
    if 'offline' is not implemented by parsing error message. To simplify
    things replace cpu-set with cpu-add command to show more clear what
    command does and just add cpu-del when CPU remove is implemented.

v2:
  * s/cpu_set/cpu-set/
  * qmp doc style fix
  * use bool type instead of opencodding online/offline string
     suggested-by: Eric Blake <eblake@redhat.com>
---
 qapi-schema.json |   11 +++++++++++
 qmp-commands.hx  |   23 +++++++++++++++++++++++
 qmp.c            |   10 ++++++++++
 3 files changed, 44 insertions(+), 0 deletions(-)

diff --git a/qapi-schema.json b/qapi-schema.json
index 751d3c2..11a5c82 100644
--- a/qapi-schema.json
+++ b/qapi-schema.json
@@ -1387,6 +1387,17 @@
 { 'command': 'cpu', 'data': {'index': 'int'} }
 
 ##
+# @cpu-add
+#
+# Adds CPU with specified ID
+#
+# @id: ID of CPU to be created, valid values [0..max_cpus)
+#
+# Returns: Nothing on success
+##
+{ 'command': 'cpu-add', 'data': {'id': 'int'} }
+
+##
 # @memsave:
 #
 # Save a portion of guest memory to a file.
diff --git a/qmp-commands.hx b/qmp-commands.hx
index 4d65422..1e5d299 100644
--- a/qmp-commands.hx
+++ b/qmp-commands.hx
@@ -385,6 +385,29 @@ Note: CPUs' indexes are obtained with the 'query-cpus' command.
 EQMP
 
     {
+        .name       = "cpu-add",
+        .args_type  = "id:i",
+        .mhandler.cmd_new = qmp_marshal_input_cpu_add,
+    },
+
+SQMP
+cpu-add
+-------
+
+Adds virtual cpu
+
+Arguments:
+
+- "id": cpu id (json-int)
+
+Example:
+
+-> { "execute": "cpu-add", "arguments": { "id": 2 } }
+<- { "return": {} }
+
+EQMP
+
+    {
         .name       = "memsave",
         .args_type  = "val:l,size:i,filename:s,cpu:i?",
         .mhandler.cmd_new = qmp_marshal_input_memsave,
diff --git a/qmp.c b/qmp.c
index ed6c7ef..dd34be6 100644
--- a/qmp.c
+++ b/qmp.c
@@ -24,6 +24,7 @@
 #include "hw/qdev.h"
 #include "sysemu/blockdev.h"
 #include "qom/qom-qobject.h"
+#include "hw/boards.h"
 
 NameInfo *qmp_query_name(Error **errp)
 {
@@ -108,6 +109,15 @@ void qmp_cpu(int64_t index, Error **errp)
     /* Just do nothing */
 }
 
+void qmp_cpu_add(int64_t id, Error **errp)
+{
+    if (current_machine->hot_add_cpu) {
+        current_machine->hot_add_cpu(id, errp);
+    } else {
+        error_setg(errp, "Not supported");
+    }
+}
+
 #ifndef CONFIG_VNC
 /* If VNC support is enabled, the "true" query-vnc command is
    defined in the VNC subsystem */
-- 
1.7.1