qmp: add dump machine type compatibility properties

To control that creating new machine type doesn't affect the previous
types (their compat_props) and to check complex compat_props inheritance
we need qmp command to print machine type compatibility properties.
This patch adds the ability to get list of all the compat_props of the
corresponding supported machines for their comparison via new optional
argument of "query-machines" command. Since information on compatibility
properties can increase the command output by a factor of 40, add an
argument to enable it, default off.

Signed-off-by: Maksim Davydov <davydov-max@yandex-team.ru>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
Acked-by: Markus Armbruster <armbru@redhat.com>
Message-ID: <20240318213550.155573-3-davydov-max@yandex-team.ru>
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>

1 files changed, 65 insertions, 2 deletions

diff --git a/qapi/machine.json b/qapi/machine.json
index 2df407e877..3e9cc3f17d 100644
--- a/qapi/machine.json
+++ b/qapi/machine.json
@@ -136,6 +136,26 @@
 { 'command': 'query-cpus-fast', 'returns': [ 'CpuInfoFast' ] }
 
 ##
+# @CompatProperty:
+#
+# Property default values specific to a machine type, for use by
+# scripts/compare-machine-types.
+#
+# @qom-type: name of the QOM type to which the default applies
+#
+# @property: name of its property to which the default applies
+#
+# @value: the default value (machine-specific default can overwrite
+#     the "default" default, to avoid this use -machine none)
+#
+# Since: 9.1
+##
+{ 'struct': 'CompatProperty',
+  'data': { 'qom-type': 'str',
+            'property': 'str',
+            'value': 'str' } }
+
+##
 # @MachineInfo:
 #
 # Information describing a machine.
@@ -166,6 +186,14 @@
 #
 # @acpi: machine type supports ACPI (since 8.0)
 #
+# @compat-props: The machine type's compatibility properties.  Only
+#     present when query-machines argument @compat-props is true.
+#     (since 9.1)
+#
+# Features:
+#
+# @unstable: Member @compat-props is experimental.
+#
 # Since: 1.2
 ##
 { 'struct': 'MachineInfo',
@@ -173,18 +201,53 @@
             '*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, also return compatibility properties.
+#     (default: false) (since 9.1)
+#
+# Features:
+#
+# @unstable: Argument @compat-props is experimental.
+#
 # 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": [
+#                       {
+#                          "qom-type": "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': { 'type': 'bool',
+                               'features': [ 'unstable' ] } },
+  'returns': ['MachineInfo'] }
 
 ##
 # @CurrentMachineParams: