qapi: Convert simple union TpmTypeOptions to flat one

Simple unions predate flat unions.  Having both complicates the QAPI
schema language and the QAPI generator.  We haven't been using simple
unions in new code for a long time, because they are less flexible and
somewhat awkward on the wire.

To prepare for their removal, convert simple union TpmTypeOptions to
an equivalent flat one, with existing enum TpmType replacing implicit
enum TpmTypeOptionsKind.  Adds some boilerplate to the schema, which
is a bit ugly, but a lot easier to maintain than the simple union
feature.

Cc: Stefan Berger <stefanb@linux.vnet.ibm.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Acked-by: Stefan Berger <stefanb@linux.ibm.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20210917143134.412106-6-armbru@redhat.com>
[Indentation tidied up]

backends/tpm/tpm_emulator.c

@@ -623,7 +623,7 @@ static TpmTypeOptions *tpm_emulator_get_tpm_options(TPMBackend *tb)
     TPMEmulator *tpm_emu = TPM_EMULATOR(tb);
     TpmTypeOptions *options = g_new0(TpmTypeOptions, 1);
 
-    options->type = TPM_TYPE_OPTIONS_KIND_EMULATOR;
+    options->type = TPM_TYPE_EMULATOR;
     options->u.emulator.data = QAPI_CLONE(TPMEmulatorOptions, tpm_emu->options);
 
     return options;

backends/tpm/tpm_passthrough.c

@@ -321,7 +321,7 @@ static TpmTypeOptions *tpm_passthrough_get_tpm_options(TPMBackend *tb)
 {
     TpmTypeOptions *options = g_new0(TpmTypeOptions, 1);
 
-    options->type = TPM_TYPE_OPTIONS_KIND_PASSTHROUGH;
+    options->type = TPM_TYPE_PASSTHROUGH;
     options->u.passthrough.data = QAPI_CLONE(TPMPassthroughOptions,
                                              TPM_PASSTHROUGH(tb)->options);
 

monitor/hmp-cmds.c

@@ -925,10 +925,10 @@ void hmp_info_tpm(Monitor *mon, const QDict *qdict)
                        c, TpmModel_str(ti->model));
 
         monitor_printf(mon, "  \\ %s: type=%s",
-                       ti->id, TpmTypeOptionsKind_str(ti->options->type));
+                       ti->id, TpmType_str(ti->options->type));
 
         switch (ti->options->type) {
-        case TPM_TYPE_OPTIONS_KIND_PASSTHROUGH:
+        case TPM_TYPE_PASSTHROUGH:
             tpo = ti->options->u.passthrough.data;
             monitor_printf(mon, "%s%s%s%s",
                            tpo->has_path ? ",path=" : "",
@@ -936,11 +936,11 @@ void hmp_info_tpm(Monitor *mon, const QDict *qdict)
                            tpo->has_cancel_path ? ",cancel-path=" : "",
                            tpo->has_cancel_path ? tpo->cancel_path : "");
             break;
-        case TPM_TYPE_OPTIONS_KIND_EMULATOR:
+        case TPM_TYPE_EMULATOR:
             teo = ti->options->u.emulator.data;
             monitor_printf(mon, ",chardev=%s", teo->chardev);
             break;
-        case TPM_TYPE_OPTIONS_KIND__MAX:
+        case TPM_TYPE__MAX:
             break;
         }
         monitor_printf(mon, "\n");

qapi/tpm.json

@@ -99,6 +99,24 @@
 { 'struct': 'TPMEmulatorOptions', 'data': { 'chardev' : 'str' },
   'if': 'CONFIG_TPM' }
 
+##
+# @TPMPassthroughOptionsWrapper:
+#
+# Since: 1.5
+##
+{ 'struct': 'TPMPassthroughOptionsWrapper',
+  'data': { 'data': 'TPMPassthroughOptions' },
+  'if': 'CONFIG_TPM' }
+
+##
+# @TPMEmulatorOptionsWrapper:
+#
+# Since: 2.11
+##
+{ 'struct': 'TPMEmulatorOptionsWrapper',
+  'data': { 'data': 'TPMEmulatorOptions' },
+  'if': 'CONFIG_TPM' }
+
 ##
 # @TpmTypeOptions:
 #
@@ -110,8 +128,10 @@
 # Since: 1.5
 ##
 { 'union': 'TpmTypeOptions',
-   'data': { 'passthrough' : 'TPMPassthroughOptions',
-             'emulator': 'TPMEmulatorOptions' },
+  'base': { 'type': 'TpmType' },
+  'discriminator': 'type',
+  'data': { 'passthrough' : 'TPMPassthroughOptionsWrapper',
+            'emulator': 'TPMEmulatorOptionsWrapper' },
   'if': 'CONFIG_TPM' }
 
 ##