qapi/machine: Make @dump-skeys command generic

Reduce misc-target.json by one target specific command.

Error message is returned for machines not implementing
TYPE_DUMP_SKEYS_INTERFACE:

  $ qemu-system-aarch64 -M virt -S -qmp stdio
  {"QMP": {"version": {"qemu": {"micro": 50, "major": 9}}, "capabilities": ["oob"]}}
  { "execute": "qmp_capabilities" }
  {"return": {}}
  { "execute": "dump-skeys", "arguments": { "filename": "/tmp/foo" }  }
  {"error": {"class": "GenericError", "desc": "Storage keys information not available for this architecture"}}

Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Message-ID: <20250310151414.11550-5-philmd@linaro.org>
Signed-off-by: Thomas Huth <thuth@redhat.com>

hw/core/machine-qmp-cmds.c

@@ -25,6 +25,7 @@
 #include "system/numa.h"
 #include "system/runstate.h"
 #include "system/system.h"
+#include "hw/s390x/storage-keys.h"
 
 /*
  * fast means: we NEVER interrupt vCPU threads to retrieve
@@ -406,3 +407,16 @@ GuidInfo *qmp_query_vm_generation_id(Error **errp)
     info->guid = qemu_uuid_unparse_strdup(&vms->guid);
     return info;
 }
+
+void qmp_dump_skeys(const char *filename, Error **errp)
+{
+    ObjectClass *mc = object_get_class(qdev_get_machine());
+    ObjectClass *oc = object_class_dynamic_cast(mc, TYPE_DUMP_SKEYS_INTERFACE);
+
+    if (!oc) {
+        error_setg(errp, "Storage keys information not available"
+                         " for this architecture");
+        return;
+    }
+    DUMP_SKEYS_INTERFACE_CLASS(oc)->qmp_dump_skeys(filename, errp);
+}

hw/s390x/s390-skeys.c

@@ -15,6 +15,7 @@
 #include "hw/qdev-properties.h"
 #include "hw/s390x/storage-keys.h"
 #include "qapi/error.h"
+#include "qapi/qapi-commands-machine.h"
 #include "qapi/qapi-commands-misc-target.h"
 #include "qobject/qdict.h"
 #include "qemu/error-report.h"
@@ -219,11 +220,6 @@ out:
     fclose(f);
 }
 
-void qmp_dump_skeys(const char *filename, Error **errp)
-{
-    s390_qmp_dump_skeys(filename, errp);
-}
-
 static bool qemu_s390_skeys_are_enabled(S390SKeysState *ss)
 {
     QEMUS390SKeysState *skeys = QEMU_S390_SKEYS(ss);

qapi/machine.json

@@ -1898,3 +1898,21 @@
 { 'command': 'x-query-interrupt-controllers',
   'returns': 'HumanReadableText',
   'features': [ 'unstable' ]}
+
+##
+# @dump-skeys:
+#
+# Dump the storage keys for an s390x guest
+#
+# @filename: the path to the file to dump to
+#
+# Since: 2.5
+#
+# .. qmp-example::
+#
+#     -> { "execute": "dump-skeys",
+#          "arguments": { "filename": "/tmp/skeys" } }
+#     <- { "return": {} }
+##
+{ 'command': 'dump-skeys',
+  'data': { 'filename': 'str' } }

qapi/misc-target.json

@@ -274,25 +274,6 @@
   'returns': 'SevAttestationReport',
   'if': 'TARGET_I386' }
 
-##
-# @dump-skeys:
-#
-# Dump guest's storage keys
-#
-# @filename: the path to the file to dump to
-#
-# Since: 2.5
-#
-# .. qmp-example::
-#
-#     -> { "execute": "dump-skeys",
-#          "arguments": { "filename": "/tmp/skeys" } }
-#     <- { "return": {} }
-##
-{ 'command': 'dump-skeys',
-  'data': { 'filename': 'str' },
-  'if': 'TARGET_S390X' }
-
 ##
 # @GICCapability:
 #