qapi: Extend -compat to set policy for unstable interfaces

New option parameters unstable-input and unstable-output set policy
for unstable interfaces just like deprecated-input and
deprecated-output set policy for deprecated interfaces (see commit
6dd75472d5 "qemu-options: New -compat to set policy for deprecated
interfaces").  This is intended for testing users of the management
interfaces.  It is experimental.

For now, this covers only syntactic aspects of QMP, i.e. stuff tagged
with feature 'unstable'.  We may want to extend it to cover semantic
aspects, or the command line.

Note that there is no good way for management application to detect
presence of these new option parameters: they are not visible output
of query-qmp-schema or query-command-line-options.  Tolerable, because
it's meant for testing.  If running with -compat fails, skip the test.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Acked-by: John Snow <jsnow@redhat.com>
Message-Id: <20211028102520.747396-10-armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
[Doc comments fixed up]

diff --git a/include/qapi/util.h b/include/qapi/util.h
index 0cc98db9f922dfb56e8e3ac4545e30a77443dbe9..81a2b13a3339c7f6341cc43f8679542949684cfe 100644 (file)
--- a/include/qapi/util.h
+++ b/include/qapi/util.h
@@ -13,6 +13,7 @@
 
 typedef enum {
     QAPI_DEPRECATED,
+    QAPI_UNSTABLE,
 } QapiSpecialFeature;
 
 typedef struct QEnumLookup {

diff --git a/qapi/compat.json b/qapi/compat.json
index 74a8493d3d27dc6b75da15ab7b572b4cd2b0ba3a..dd7261ae2a95156741ad0d82e80d37cb78bee6f7 100644 (file)
--- a/qapi/compat.json
+++ b/qapi/compat.json
@@ -47,9 +47,15 @@
 #
 # @deprecated-input: how to handle deprecated input (default 'accept')
 # @deprecated-output: how to handle deprecated output (default 'accept')
+# @unstable-input: how to handle unstable input (default 'accept')
+#                  (since 6.2)
+# @unstable-output: how to handle unstable output (default 'accept')
+#                   (since 6.2)
 #
 # Since: 6.0
 ##
 { 'struct': 'CompatPolicy',
   'data': { '*deprecated-input': 'CompatPolicyInput',
-            '*deprecated-output': 'CompatPolicyOutput' } }
+            '*deprecated-output': 'CompatPolicyOutput',
+            '*unstable-input': 'CompatPolicyInput',
+            '*unstable-output': 'CompatPolicyOutput' } }

diff --git a/qapi/qapi-util.c b/qapi/qapi-util.c
index 53b493cb7e44c897d23ac2bd0d3b2ee6149cc39c..fda7044539040e7683b4735a302f51b1cbad8531 100644 (file)
--- a/qapi/qapi-util.c
+++ b/qapi/qapi-util.c
@@ -49,6 +49,12 @@ bool compat_policy_input_ok(unsigned special_features,
                                     error_class, kind, name, errp)) {
         return false;
     }
+    if ((special_features & (1u << QAPI_UNSTABLE))
+        && !compat_policy_input_ok1("Unstable",
+                                    policy->unstable_input,
+                                    error_class, kind, name, errp)) {
+        return false;
+    }
     return true;
 }
 

diff --git a/qapi/qobject-output-visitor.c b/qapi/qobject-output-visitor.c
index b155bf41499d327ca23d3d4ef9e5b8bf29c46455..74770edd73c68849b2099bef597b3953aa7716fa 100644 (file)
--- a/qapi/qobject-output-visitor.c
+++ b/qapi/qobject-output-visitor.c
@@ -212,8 +212,12 @@ static bool qobject_output_type_null(Visitor *v, const char *name,
 static bool qobject_output_policy_skip(Visitor *v, const char *name,
                                        unsigned special_features)
 {
-    return !(special_features & 1u << QAPI_DEPRECATED)
-        || v->compat_policy.deprecated_output == COMPAT_POLICY_OUTPUT_HIDE;
+    CompatPolicy *pol = &v->compat_policy;
+
+    return ((special_features & 1u << QAPI_DEPRECATED)
+            && pol->deprecated_output == COMPAT_POLICY_OUTPUT_HIDE)
+        || ((special_features & 1u << QAPI_UNSTABLE)
+            && pol->unstable_output == COMPAT_POLICY_OUTPUT_HIDE);
 }
 
 /* Finish building, and return the root object.

diff --git a/qemu-options.hx b/qemu-options.hx
index 5f375bbfa666f5e8064e5e7816d3e47631dbba9f..f051536b630f2f018088f46b509d17dac427cd55 100644 (file)
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -3641,7 +3641,9 @@ DEFHEADING(Debug/Expert options:)
 
 DEF("compat", HAS_ARG, QEMU_OPTION_compat,
     "-compat [deprecated-input=accept|reject|crash][,deprecated-output=accept|hide]\n"
-    "                Policy for handling deprecated management interfaces\n",
+    "                Policy for handling deprecated management interfaces\n"
+    "-compat [unstable-input=accept|reject|crash][,unstable-output=accept|hide]\n"
+    "                Policy for handling unstable management interfaces\n",
     QEMU_ARCH_ALL)
 SRST
 ``-compat [deprecated-input=@var{input-policy}][,deprecated-output=@var{output-policy}]``
@@ -3659,6 +3661,22 @@ SRST
         Suppress deprecated command results and events
 
     Limitation: covers only syntactic aspects of QMP.
+
+``-compat [unstable-input=@var{input-policy}][,unstable-output=@var{output-policy}]``
+    Set policy for handling unstable management interfaces (experimental):
+
+    ``unstable-input=accept`` (default)
+        Accept unstable commands and arguments
+    ``unstable-input=reject``
+        Reject unstable commands and arguments
+    ``unstable-input=crash``
+        Crash on unstable commands and arguments
+    ``unstable-output=accept`` (default)
+        Emit unstable command results and events
+    ``unstable-output=hide``
+        Suppress unstable command results and events
+
+    Limitation: covers only syntactic aspects of QMP.
 ERST
 
 DEF("fw_cfg", HAS_ARG, QEMU_OPTION_fwcfg,

diff --git a/scripts/qapi/events.py b/scripts/qapi/events.py
index 82475e84ecc991ca9a32331613aa645f46115617..27b44c49f5e92056a95a6e5cb87e8babf2bfb2b4 100644 (file)
--- a/scripts/qapi/events.py
+++ b/scripts/qapi/events.py
@@ -109,13 +109,15 @@ def gen_event_send(name: str,
         if not boxed:
             ret += gen_param_var(arg_type)
 
-    if 'deprecated' in [f.name for f in features]:
-        ret += mcgen('''
+    for f in features:
+        if f.is_special():
+            ret += mcgen('''
 
-    if (compat_policy.deprecated_output == COMPAT_POLICY_OUTPUT_HIDE) {
+    if (compat_policy.%(feat)s_output == COMPAT_POLICY_OUTPUT_HIDE) {
         return;
     }
-''')
+''',
+                         feat=f.name)
 
     ret += mcgen('''
 

diff --git a/scripts/qapi/schema.py b/scripts/qapi/schema.py
index 55f82d7389c4180595f10f76ff6ad401abb77295..b7b3fc0ce400c80edd7395be7acced5471f2e9cc 100644 (file)
--- a/scripts/qapi/schema.py
+++ b/scripts/qapi/schema.py
@@ -254,9 +254,11 @@ class QAPISchemaType(QAPISchemaEntity):
 
     def check(self, schema):
         QAPISchemaEntity.check(self, schema)
-        if 'deprecated' in [f.name for f in self.features]:
-            raise QAPISemError(
-                self.info, "feature 'deprecated' is not supported for types")
+        for feat in self.features:
+            if feat.is_special():
+                raise QAPISemError(
+                    self.info,
+                    f"feature '{feat.name}' is not supported for types")
 
     def describe(self):
         assert self.meta
@@ -726,7 +728,7 @@ class QAPISchemaFeature(QAPISchemaMember):
     role = 'feature'
 
     def is_special(self):
-        return self.name in ('deprecated')
+        return self.name in ('deprecated', 'unstable')
 
 
 class QAPISchemaObjectTypeMember(QAPISchemaMember):