Revert "tpm: Clean up error reporting in tpm_init_tpmdev()"

This reverts commit d10e05f15d.

We report some -tpmdev failures, but then continue as if all was fine.
Reproducer:

    $ qemu-system-x86_64 -nodefaults -S -display none -monitor stdio -chardev null,id=tpm0 -tpmdev emulator,id=tpm0,chardev=chrtpm -device tpm-tis,tpmdev=tpm0
    qemu-system-x86_64: -tpmdev emulator,id=tpm0,chardev=chrtpm: tpm-emulator: tpm chardev 'chrtpm' not found.
    qemu-system-x86_64: -tpmdev emulator,id=tpm0,chardev=chrtpm: tpm-emulator: Could not cleanly shutdown the TPM: No such file or directory
    QEMU 5.0.90 monitor - type 'help' for more information
    (qemu) qemu-system-x86_64: -device tpm-tis,tpmdev=tpm0: Property 'tpm-tis.tpmdev' can't find value 'tpm0'
    $ echo $?
    1

This is a regression caused by commit d10e05f15d "tpm: Clean up error
reporting in tpm_init_tpmdev()".  It's incomplete: be->create(opts)
continues to use error_report(), and we don't set an error when it
fails.

I figure converting the create() methods to Error would make some
sense, but I'm not sure it's worth the effort right now.  Revert the
broken commit instead, and add a comment to tpm_init_tpmdev().

Straightforward conflict in tpm.c resolved.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Stefan Berger <stefanb@linux.ibm.com>
Signed-off-by: Stefan Berger <stefanb@linux.ibm.com>

include/sysemu/tpm.h

@@ -16,7 +16,7 @@
 #include "qom/object.h"
 
 int tpm_config_parse(QemuOptsList *opts_list, const char *optarg);
-void tpm_init(void);
+int tpm_init(void);
 void tpm_cleanup(void);
 
 typedef enum TPMVersion {

softmmu/vl.c

@@ -4258,7 +4258,9 @@ void qemu_init(int argc, char **argv, char **envp)
                       user_creatable_add_opts_foreach,
                       object_create_delayed, &error_fatal);
 
-    tpm_init();
+    if (tpm_init() < 0) {
+        exit(1);
+    }
 
     blk_mig_init();
     ram_mig_init();

stubs/tpm.c

@@ -10,8 +10,9 @@
 #include "sysemu/tpm.h"
 #include "hw/acpi/tpm.h"
 
-void tpm_init(void)
+int tpm_init(void)
 {
+    return 0;
 }
 
 void tpm_cleanup(void)

tpm.c

@@ -81,26 +81,33 @@ TPMBackend *qemu_find_tpm_be(const char *id)
 
 static int tpm_init_tpmdev(void *dummy, QemuOpts *opts, Error **errp)
 {
+    /*
+     * Use of error_report() in a function with an Error ** parameter
+     * is suspicious.  It is okay here.  The parameter only exists to
+     * make the function usable with qemu_opts_foreach().  It is not
+     * actually used.
+     */
     const char *value;
     const char *id;
     const TPMBackendClass *be;
     TPMBackend *drv;
+    Error *local_err = NULL;
     int i;
 
     if (!QLIST_EMPTY(&tpm_backends)) {
-        error_setg(errp, "Only one TPM is allowed.");
+        error_report("Only one TPM is allowed.");
         return 1;
     }
 
     id = qemu_opts_id(opts);
     if (id == NULL) {
-        error_setg(errp, QERR_MISSING_PARAMETER, "id");
+        error_report(QERR_MISSING_PARAMETER, "id");
         return 1;
     }
 
     value = qemu_opt_get(opts, "type");
     if (!value) {
-        error_setg(errp, QERR_MISSING_PARAMETER, "type");
+        error_report(QERR_MISSING_PARAMETER, "type");
         tpm_display_backend_drivers();
         return 1;
     }
@@ -108,14 +115,15 @@ static int tpm_init_tpmdev(void *dummy, QemuOpts *opts, Error **errp)
     i = qapi_enum_parse(&TpmType_lookup, value, -1, NULL);
     be = i >= 0 ? tpm_be_find_by_type(i) : NULL;
     if (be == NULL) {
-        error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "type",
-                   "a TPM backend type");
+        error_report(QERR_INVALID_PARAMETER_VALUE,
+                     "type", "a TPM backend type");
         tpm_display_backend_drivers();
         return 1;
     }
 
     /* validate backend specific opts */
-    if (!qemu_opts_validate(opts, be->opts, errp)) {
+    if (!qemu_opts_validate(opts, be->opts, &local_err)) {
+        error_report_err(local_err);
         return 1;
     }
 
@@ -148,10 +156,14 @@ void tpm_cleanup(void)
  * Initialize the TPM. Process the tpmdev command line options describing the
  * TPM backend.
  */
-void tpm_init(void)
+int tpm_init(void)
 {
-    qemu_opts_foreach(qemu_find_opts("tpmdev"),
-                      tpm_init_tpmdev, NULL, &error_fatal);
+    if (qemu_opts_foreach(qemu_find_opts("tpmdev"),
+                          tpm_init_tpmdev, NULL, NULL)) {
+        return -1;
+    }
+
+    return 0;
 }
 
 /*