[PATCH 2/8] qapi: add 'warn' option to CompatPolicyInput

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

This prints a warning on stderr every time a policy violation
is encountered, but accepts the input.

Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
---
 qapi/compat.json |  4 +++-
 qapi/qapi-util.c |  4 ++++
 qemu-options.hx  | 12 ++++++++----
 3 files changed, 15 insertions(+), 5 deletions(-)

diff --git a/qapi/compat.json b/qapi/compat.json
index 0f90ea1f524..dfa3fea0577 100644
--- a/qapi/compat.json
+++ b/qapi/compat.json
@@ -17,10 +17,12 @@
 #
 # @crash: abort() the process
 #
+# @warn: Accept with a warning printed to stderr (Since: 11.2)
+#
 # Since: 6.0
 ##
 { 'enum': 'CompatPolicyInput',
-  'data': [ 'accept', 'reject', 'crash' ] }
+  'data': [ 'accept', 'reject', 'crash', 'warn' ] }
 
 ##
 # @CompatPolicyOutput:
diff --git a/qapi/qapi-util.c b/qapi/qapi-util.c
index 93898f57a05..f81a171a5b1 100644
--- a/qapi/qapi-util.c
+++ b/qapi/qapi-util.c
@@ -28,6 +28,10 @@ static bool compat_policy_input_ok1(CompatPolicyInput policy,
     switch (policy) {
     case COMPAT_POLICY_INPUT_ACCEPT:
         return true;
+    case COMPAT_POLICY_INPUT_WARN:
+        warn_report("%s %s %s disabled by policy",
+                    adjective, kind, name);
+        return true;
     case COMPAT_POLICY_INPUT_REJECT:
         error_set(errp, error_class, "%s %s %s disabled by policy",
                   adjective, kind, name);
diff --git a/qemu-options.hx b/qemu-options.hx
index f72f30e246d..16d9c6c9072 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -4693,9 +4693,9 @@ DEFHEADING()
 DEFHEADING(Debug/Expert options:)
 
 DEF("compat", HAS_ARG, QEMU_OPTION_compat,
-    "-compat [deprecated-input=accept|reject|crash][,deprecated-output=accept|hide]\n"
+    "-compat [deprecated-input=accept|reject|crash|warn][,deprecated-output=accept|hide]\n"
     "                Policy for handling deprecated management interfaces\n"
-    "-compat [unstable-input=accept|reject|crash][,unstable-output=accept|hide]\n"
+    "-compat [unstable-input=accept|reject|crash|warn][,unstable-output=accept|hide]\n"
     "                Policy for handling unstable management interfaces\n",
     QEMU_ARCH_ALL)
 SRST
@@ -4703,7 +4703,9 @@ SRST
     Set policy for handling deprecated management interfaces (experimental):
 
     ``deprecated-input=accept`` (default)
-        Accept deprecated commands and arguments
+        Accept deprecated commands and arguments silently
+    ``deprecated-input=warn``
+        Accept deprecated commands and arguments with warning on stderr
     ``deprecated-input=reject``
         Reject deprecated commands and arguments
     ``deprecated-input=crash``
@@ -4719,7 +4721,9 @@ SRST
     Set policy for handling unstable management interfaces (experimental):
 
     ``unstable-input=accept`` (default)
-        Accept unstable commands and arguments
+        Accept unstable commands and arguments silently
+    ``unstable-input=warn``
+        Accept unstable commands and arguments with warning on stderr
     ``unstable-input=reject``
         Reject unstable commands and arguments
     ``unstable-input=crash``
-- 
2.56.0