[v7,2/4] qmp: add dump machine type compatibility properties

diff --git a/hw/core/machine-qmp-cmds.c b/hw/core/machine-qmp-cmds.c
index 3860a50c3b..a49d0dc362 100644
--- a/hw/core/machine-qmp-cmds.c
+++ b/hw/core/machine-qmp-cmds.c
@@ -66,7 +66,8 @@  CpuInfoFastList *qmp_query_cpus_fast(Error **errp)
     return head;
 }
 
-MachineInfoList *qmp_query_machines(Error **errp)
+MachineInfoList *qmp_query_machines(bool has_compat_props, bool compat_props,
+                                    Error **errp)
 {
     GSList *el, *machines = object_class_get_list(TYPE_MACHINE, false);
     MachineInfoList *mach_list = NULL;
@@ -98,6 +99,26 @@  MachineInfoList *qmp_query_machines(Error **errp)
             info->default_ram_id = g_strdup(mc->default_ram_id);
         }
 
+        if (compat_props && mc->compat_props) {
+            int i;
+            info->compat_props = NULL;
+            CompatPropertyList **tail = &(info->compat_props);
+            info->has_compat_props = true;
+
+            for (i = 0; i < mc->compat_props->len; i++) {
+                GlobalProperty *mt_prop = g_ptr_array_index(mc->compat_props,
+                                                            i);
+                CompatProperty *prop;
+
+                prop = g_malloc0(sizeof(*prop));
+                prop->driver = g_strdup(mt_prop->driver);
+                prop->property = g_strdup(mt_prop->property);
+                prop->value = g_strdup(mt_prop->value);
+
+                QAPI_LIST_APPEND(tail, prop);
+            }
+        }
+
         QAPI_LIST_PREPEND(mach_list, info);
     }
 
diff --git a/qapi/machine.json b/qapi/machine.json
index b6d634b30d..15a1d62f42 100644
--- a/qapi/machine.json
+++ b/qapi/machine.json
@@ -135,6 +135,29 @@ 
 ##
 { 'command': 'query-cpus-fast', 'returns': [ 'CpuInfoFast' ] }
 
+##
+# @CompatProperty:
+#
+# Machine type compatibility property that uses in machine
+# definitions to specify default values.  It's based on representaion
+# of properties in QEMU and created for machine type comparing
+# (see scripts/compare-machine-types.py)
+#
+# @driver: name of the driver which default value of certain property
+#     is changed in the machine type
+#
+# @property: property name
+#
+# @value: property value that will be assigned as default to
+#     the driver by machine type
+#
+# Since: 9.0
+##
+{ 'struct': 'CompatProperty',
+  'data': { 'driver': 'str',
+            'property': 'str',
+            'value': 'str' } }
+
 ##
 # @MachineInfo:
 #
@@ -166,6 +189,13 @@ 
 #
 # @acpi: machine type supports ACPI (since 8.0)
 #
+# @compat-props: List of the machine type's compatibility properties.
+#     (since 9.0)
+#
+# Features:
+#
+# @unstable: Member @compat-props is experimental.
+#
 # Since: 1.2
 ##
 { 'struct': 'MachineInfo',
@@ -173,18 +203,48 @@ 
             '*is-default': 'bool', 'cpu-max': 'int',
             'hotpluggable-cpus': 'bool',  'numa-mem-supported': 'bool',
             'deprecated': 'bool', '*default-cpu-type': 'str',
-            '*default-ram-id': 'str', 'acpi': 'bool' } }
+            '*default-ram-id': 'str', 'acpi': 'bool',
+            '*compat-props': { 'type': ['CompatProperty'],
+                               'features': ['unstable'] } } }
 
 ##
 # @query-machines:
 #
 # Return a list of supported machines
 #
+# @compat-props: if true return will contain information about
+#     machine type compatibility properties (since 9.0)
+#
 # Returns: a list of MachineInfo
 #
 # Since: 1.2
+#
+# Example:
+#
+# -> { "execute": "query-machines", "arguments": { "compat-props": true } }
+# <- { "return": [
+#          {
+#              "hotpluggable-cpus": true,
+#              "name": "pc-q35-6.2",
+#              "compat-props": [
+#                  {
+#                      "driver": "virtio-mem",
+#                      "property": "unplugged-inaccessible",
+#                      "value": "off"
+#                   }
+#               ],
+#               "numa-mem-supported": false,
+#               "default-cpu-type": "qemu64-x86_64-cpu",
+#               "cpu-max": 288,
+#               "deprecated": false,
+#               "default-ram-id": "pc.ram"
+#           },
+#           ...
+#    }
 ##
-{ 'command': 'query-machines', 'returns': ['MachineInfo'] }
+{ 'command': 'query-machines',
+  'data': { '*compat-props': 'bool' },
+  'returns': ['MachineInfo'] }
 
 ##
 # @CurrentMachineParams:
diff --git a/tests/qtest/fuzz/qos_fuzz.c b/tests/qtest/fuzz/qos_fuzz.c
index e403d373a0..b71e945c5f 100644
--- a/tests/qtest/fuzz/qos_fuzz.c
+++ b/tests/qtest/fuzz/qos_fuzz.c
@@ -46,7 +46,7 @@  static void qos_set_machines_devices_available(void)
     MachineInfoList *mach_info;
     ObjectTypeInfoList *type_info;
 
-    mach_info = qmp_query_machines(&error_abort);
+    mach_info = qmp_query_machines(false, false, &error_abort);
     machines_apply_to_node(mach_info);
     qapi_free_MachineInfoList(mach_info);