[Qemu-devel] [PATCH 11/19] Add a query-devices command to QMP

["Daniel P. Berrange" <berrange@redhat.com>]

Adds a command to QMP called 'query-devices' to allow for discovery
of all devices known to the QEMU binary. THis is inteded to replace
use of the '-device ?' and '-device devtype,?' command line args

The data format is designed to allow easy extension to support more
data:

    [
        {
            "name": "virtio-9p-pci",
            "creatable": true,
            "bus": "PCI",
            "props": [
                {
                    "name": "indirect_desc",
                    "type": "bit",
                    "info": "on/off"
                },
                {
                    "name": "mount_tag",
                    "type": "string",
                    "info": "string"
                },
                {
                    "name": "fsdev",
                    "type": "string",
                    "info": "string"
                }
            ]
        },
        {
            "name": "virtio-balloon-pci",
            "creatable": true,
            "bus": "PCI",
            "props": [
                {
                    "name": "indirect_desc",
                    "type": "bit",
                    "info": "on/off"
                }
            ]
        },
        ...
    ]

No legacy readline monitor output is provided.

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
---
 hw/qdev.c |  146 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 hw/qdev.h |    2 +
 monitor.c |    8 +++
 3 files changed, 156 insertions(+), 0 deletions(-)

diff --git a/hw/qdev.c b/hw/qdev.c
index 1186dfa..0a10c3c 100644
--- a/hw/qdev.c
+++ b/hw/qdev.c
@@ -29,6 +29,7 @@
 #include "qdev.h"
 #include "sysemu.h"
 #include "monitor.h"
+#include "qjson.h"
 
 static int qdev_hotplug = 0;
 
@@ -810,3 +811,148 @@ int do_device_del(Monitor *mon, const QDict *qdict, QObject **ret_data)
     }
     return qdev_unplug(dev);
 }
+
+static const char *qdev_property_type_to_string(int type) {
+    switch (type) {
+    case PROP_TYPE_UNSPEC:
+	return "unknown";
+    case PROP_TYPE_UINT8:
+	return "uint8";
+    case PROP_TYPE_UINT16:
+	return "uint16";
+    case PROP_TYPE_UINT32:
+	return "uint32";
+    case PROP_TYPE_INT32:
+	return "int32";
+    case PROP_TYPE_UINT64:
+	return "uint64";
+    case PROP_TYPE_TADDR:
+	return "taddr";
+    case PROP_TYPE_MACADDR:
+	return "macaddr";
+    case PROP_TYPE_DRIVE:
+	return "drive";
+    case PROP_TYPE_CHR:
+	return "chr";
+    case PROP_TYPE_STRING:
+	return "string";
+    case PROP_TYPE_NETDEV:
+	return "netdev";
+    case PROP_TYPE_VLAN:
+	return "vlan";
+    case PROP_TYPE_PTR:
+	return "pointer";
+    case PROP_TYPE_BIT:
+	return "bit";
+    }
+    return NULL;
+}
+
+
+/*
+ * Describe capabilities of all devices registered with qdev
+ *
+ * The returned output is a QList, each element is a QDict
+ * describing a single device type. The valid keys for the
+ * device dictionary are
+ *
+ *  - "name": the short name of the device
+ *  - "bus": the name of the bus type for the device
+ *  - "alias": an alias by which the device is also known (optional)
+ *  - "description": a long description the device (optional)
+ *  - "props": a list of device properties
+ *  - "creatable": whether this device can be created on command line
+ *
+ * The 'props' list is a QList, with each element being a
+ * QDict describing a single property of the device. The
+ * valid property keys are
+ *
+ *  - "name": the short name of the property
+ *  - "info": short description of the property
+ *  - "type": the data type of the property value
+ *
+ * An example:
+ *
+ *   [
+ *       {
+ *           "name": "virtio-9p-pci",
+ *           "creatable": true,
+ *           "bus": "PCI",
+ *           "props": [
+ *               {
+ *                   "name": "indirect_desc",
+ *                   "type": "bit",
+ *                   "info": "on/off"
+ *               },
+ *               {
+ *                   "name": "mount_tag",
+ *                   "type": "string",
+ *                   "info": "string"
+ *               },
+ *               {
+ *                   "name": "fsdev",
+ *                   "type": "string",
+ *                   "info": "string"
+ *               }
+ *           ]
+ *       },
+ *       {
+ *           "name": "virtio-balloon-pci",
+ *           "creatable": true,
+ *           "bus": "PCI",
+ *           "props": [
+ *               {
+ *                   "name": "indirect_desc",
+ *                   "type": "bit",
+ *                   "info": "on/off"
+ *               }
+ *           ]
+ *       },
+ *       ....
+ *   ]
+ */
+void do_info_devices(Monitor *mon, QObject **data)
+{
+    DeviceInfo *info;
+    QList *devs = qlist_new();
+
+    for (info = device_info_list; info != NULL; info = info->next) {
+	QObject *dev;
+	QList *props = qlist_new();
+	Property *prop;
+
+	for (prop = info->props; prop && prop->name; prop++) {
+	    QObject *entry;
+	    /*
+	     * TODO Properties without a parser are just for dirty hacks.
+	     * qdev_prop_ptr is the only such PropertyInfo.  It's marked
+	     * for removal.  This conditional should be removed along with
+	     * it.
+	     */
+	    if (!prop->info->parse) {
+		continue;           /* no way to set it, don't show */
+	    }
+
+	    const char *type = qdev_property_type_to_string(prop->info->type);
+
+	    entry = qobject_from_jsonf("{ 'name': %s, 'info': %s, 'type': %s }",
+				       prop->name, prop->info->name, type);
+
+	    qlist_append_obj(props, entry);
+	}
+
+	dev = qobject_from_jsonf("{ 'name': %s, 'bus': %s, 'props': %p, 'creatable': %i }",
+				 info->name,
+				 info->bus_info->name,
+				 props,
+				 info->no_user ? 0 : 1);
+	if (info->alias)
+	    qdict_put_obj((QDict*)dev, "alias", QOBJECT(qstring_from_str(info->alias)));
+	if (info->desc)
+	    qdict_put_obj((QDict*)dev, "description", QOBJECT(qstring_from_str(info->desc)));
+
+	qlist_append_obj(devs, dev);
+    }
+
+    *data = QOBJECT(devs);
+}
diff --git a/hw/qdev.h b/hw/qdev.h
index a44060e..fe6f981 100644
--- a/hw/qdev.h
+++ b/hw/qdev.h
@@ -280,6 +280,8 @@ void qdev_prop_set_defaults(DeviceState *dev, Property *props);
 void qdev_prop_register_global_list(GlobalProperty *props);
 void qdev_prop_set_globals(DeviceState *dev);
 
+void do_info_devices(Monitor *mon, QObject **data);
+
 /* This is a nasty hack to allow passing a NULL bus to qdev_create.  */
 extern struct BusInfo system_bus_info;
 
diff --git a/monitor.c b/monitor.c
index b6aa2b4..13f70a0 100644
--- a/monitor.c
+++ b/monitor.c
@@ -2458,6 +2458,14 @@ static const mon_cmd_t info_cmds[] = {
         .mhandler.info_new = do_info_machines,
     },
     {
+        .name       = "devices",
+        .args_type  = "",
+        .params     = "",
+        .help       = "show the registered QDev devices",
+        .user_print = monitor_user_noop,
+        .mhandler.info_new = do_info_devices,
+    },
+    {
         .name       = "commands",
         .args_type  = "",
         .params     = "",
-- 
1.6.6.1