[RFC PATCH v3 4/5] qapi: Allow device_add to execute in machine initialized phase

[Damien Hedde]

From: Mirela Grujic <mirela.grujic@greensocs.com>

This commit allows to use the QMP command to add a cold-plugged
device like we can do with the CLI option -device.

Note: for device_add command in qdev.json adding the 'allow-preconfig'
option has no effect because the command appears to bypass QAPI (see
TODO at qapi/qdev.json:61). The option is added there solely to
document the intent.
For the same reason, the flags have to be explicitly set in
monitor_init_qmp_commands() when the device_add command is registered.

Signed-off-by: Mirela Grujic <mirela.grujic@greensocs.com>
Signed-off-by: Damien Hedde <damien.hedde@greensocs.com>
Acked-by: Alistair Francis <alistair.francis@wdc.com>
---
 qapi/qdev.json         | 3 ++-
 monitor/misc.c         | 2 +-
 softmmu/qdev-monitor.c | 6 ++++++
 3 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/qapi/qdev.json b/qapi/qdev.json
index 69656b14df..51c5b2fbcf 100644
--- a/qapi/qdev.json
+++ b/qapi/qdev.json
@@ -74,7 +74,8 @@
 { 'command': 'device_add',
   'data': {'driver': 'str', '*bus': 'str', '*id': 'str'},
   'gen': false, # so we can get the additional arguments
-  'features': ['json-cli'] }
+  'features': ['json-cli'],
+  'allow-preconfig': true }
 
 ##
 # @device_del:
diff --git a/monitor/misc.c b/monitor/misc.c
index a3a6e47844..fd56dd8f08 100644
--- a/monitor/misc.c
+++ b/monitor/misc.c
@@ -233,7 +233,7 @@ static void monitor_init_qmp_commands(void)
     qmp_init_marshal(&qmp_commands);
 
     qmp_register_command(&qmp_commands, "device_add",
-                         qmp_device_add, 0, 0);
+                         qmp_device_add, QCO_ALLOW_PRECONFIG, 0);
 
     QTAILQ_INIT(&qmp_cap_negotiation_commands);
     qmp_register_command(&qmp_cap_negotiation_commands, "qmp_capabilities",
diff --git a/softmmu/qdev-monitor.c b/softmmu/qdev-monitor.c
index 1d6a1c4716..06729145b7 100644
--- a/softmmu/qdev-monitor.c
+++ b/softmmu/qdev-monitor.c
@@ -842,6 +842,12 @@ void qmp_device_add(QDict *qdict, QObject **ret_data, 
Error **errp)
     QemuOpts *opts;
     DeviceState *dev;
 
+    if (!phase_check(MACHINE_INIT_PHASE_INITIALIZED)) {
+        error_setg(errp, "The command is permitted only after "
+                         "the machine is initialized");
+        return;
+    }
+
     opts = qemu_opts_from_qdict(qemu_find_opts("device"), qdict, errp);
     if (!opts) {
         return;
-- 
2.33.0