Declare -realtime as deprecated

The old -realtime mlock=on|off parameter does exactly the same as the
new -overcommit mem-lock=on|off parameter. Additionally, "-realtime"
does not activate any additional "realtime" capabilities as the name
might indicate. We should avoid to confuse the users this way, so
let's deprecate the old -realtime option.

Signed-off-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Eduardo Habkost <ehabkost@redhat.com>
Message-Id: <20190411175345.19414-1-thuth@redhat.com>

qemu-deprecated.texi

@@ -72,6 +72,11 @@ backend settings instead of environment variables.  To ease migration to
 the new format, the ``-audiodev-help'' option can be used to convert
 the current values of the environment variables to ``-audiodev'' options.
 
+@subsection -realtime (since 4.1)
+
+The @code{-realtime mlock=on|off} argument has been replaced by the
+@code{-overcommit mem-lock=on|off} argument.
+
 @section QEMU Machine Protocol (QMP) commands
 
 @subsection block-dirty-bitmap-add "autoload" parameter (since 2.12.0)

vl.c

@@ -3927,6 +3927,8 @@ int main(int argc, char **argv, char **envp)
                 }
                 break;
             case QEMU_OPTION_realtime:
+                warn_report("'-realtime mlock=...' is deprecated, please use "
+                             "'-overcommit mem-lock=...' instead");
                 opts = qemu_opts_parse_noisily(qemu_find_opts("realtime"),
                                                optarg, false);
                 if (!opts) {