accel: abort if we fail to load the accelerator plugin

if QEMU is configured with modules enabled, it is possible that the
load of an accelerator module will fail.
Exit in this case, relying on module_object_class_by_name to report
the specific load error if any.

Signed-off-by: Claudio Fontana <cfontana@suse.de>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>

[claudio: changed abort() to exit(1)]
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20220929093035.4231-6-cfontana@suse.de>

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

accel/accel-softmmu.c

@@ -66,6 +66,7 @@ void accel_init_ops_interfaces(AccelClass *ac)
 {
     const char *ac_name;
     char *ops_name;
+    ObjectClass *oc;
     AccelOpsClass *ops;
 
     ac_name = object_class_get_name(OBJECT_CLASS(ac));
@@ -73,8 +74,13 @@ void accel_init_ops_interfaces(AccelClass *ac)
 
     ops_name = g_strdup_printf("%s" ACCEL_OPS_SUFFIX, ac_name);
     ops = ACCEL_OPS_CLASS(module_object_class_by_name(ops_name));
+    oc = module_object_class_by_name(ops_name);
+    if (!oc) {
+        error_report("fatal: could not load module for type '%s'", ops_name);
+        exit(1);
+    }
     g_free(ops_name);
-
+    ops = ACCEL_OPS_CLASS(oc);
     /*
      * all accelerators need to define ops, providing at least a mandatory
      * non-NULL create_vcpu_thread operation.