vl: switch -M parsing to keyval

Switch from QemuOpts to keyval.  This enables the introduction
of non-scalar machine properties, and JSON syntax in the future.

For JSON syntax to be supported right now, we would have to
consider what would happen if string-based dictionaries (produced by
-M key=val) were to be merged with strongly-typed dictionaries
(produced by -M {'key': 123}).

The simplest way out is to never enter the situation, and only allow one
-M option when JSON syntax is in use.  However, we want options such as
-smp to become syntactic sugar for -M, and this is a problem; as soon
as -smp becomes a shortcut for -M, QEMU would forbid using -M '{....}'
together with -smp.  Therefore, allowing JSON syntax right now for -M
would be a forward-compatibility nightmare and it would be impossible
anyway to introduce -M incrementally in tools.

Instead, support for JSON syntax is delayed until after the main
options are converted to QOM compound properties.  These include -boot,
-acpitable, -smbios, -m, -semihosting-config, -rtc and -fw_cfg.  Once JSON
syntax is introduced, these options will _also_ be forbidden together
with -M '{...}'.

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

softmmu/vl.c

@@ -145,6 +145,8 @@ static const char *cpu_option;
 static const char *mem_path;
 static const char *incoming;
 static const char *loadvm;
+static const char *accelerators;
+static QDict *machine_opts_dict;
 static QTAILQ_HEAD(, ObjectOption) object_opts = QTAILQ_HEAD_INITIALIZER(object_opts);
 static ram_addr_t maxram_size;
 static uint64_t ram_slots;
@@ -235,21 +237,6 @@ static QemuOptsList qemu_option_rom_opts = {
     },
 };
 
-static QemuOptsList qemu_machine_opts = {
-    .name = "machine",
-    .implied_opt_name = "type",
-    .merge_lists = true,
-    .head = QTAILQ_HEAD_INITIALIZER(qemu_machine_opts.head),
-    .desc = {
-        /*
-         * no elements => accept any
-         * sanity checking will happen later
-         * when setting machine properties
-         */
-        { }
-    },
-};
-
 static QemuOptsList qemu_accel_opts = {
     .name = "accel",
     .implied_opt_name = "accel",
@@ -498,16 +485,6 @@ static QemuOptsList qemu_action_opts = {
     },
 };
 
-/**
- * Get machine options
- *
- * Returns: machine options (never null).
- */
-static QemuOpts *qemu_get_machine_opts(void)
-{
-    return qemu_find_opts_singleton("machine");
-}
-
 const char *qemu_get_vm_name(void)
 {
     return qemu_name;
@@ -815,33 +792,6 @@ static MachineClass *find_default_machine(GSList *machines)
     return default_machineclass;
 }
 
-static int machine_help_func(QemuOpts *opts, MachineState *machine)
-{
-    ObjectProperty *prop;
-    ObjectPropertyIterator iter;
-
-    if (!qemu_opt_has_help_opt(opts)) {
-        return 0;
-    }
-
-    object_property_iter_init(&iter, OBJECT(machine));
-    while ((prop = object_property_iter_next(&iter))) {
-        if (!prop->set) {
-            continue;
-        }
-
-        printf("%s.%s=%s", MACHINE_GET_CLASS(machine)->name,
-               prop->name, prop->type);
-        if (prop->description) {
-            printf(" (%s)\n", prop->description);
-        } else {
-            printf("\n");
-        }
-    }
-
-    return 1;
-}
-
 static void version(void)
 {
     printf("QEMU emulator version " QEMU_FULL_VERSION "\n"
@@ -1554,33 +1504,31 @@ static gint machine_class_cmp(gconstpointer a, gconstpointer b)
                   object_class_get_name(OBJECT_CLASS(mc1)));
 }
 
-static MachineClass *machine_parse(const char *name, GSList *machines)
+static void machine_help_func(const QDict *qdict)
 {
-    MachineClass *mc;
-    GSList *el;
+    GSList *machines, *el;
+    const char *type = qdict_get_try_str(qdict, "type");
 
-    if (is_help_option(name)) {
-        printf("Supported machines are:\n");
-        machines = g_slist_sort(machines, machine_class_cmp);
-        for (el = machines; el; el = el->next) {
-            MachineClass *mc = el->data;
-            if (mc->alias) {
-                printf("%-20s %s (alias of %s)\n", mc->alias, mc->desc, mc->name);
-            }
-            printf("%-20s %s%s%s\n", mc->name, mc->desc,
-                   mc->is_default ? " (default)" : "",
-                   mc->deprecation_reason ? " (deprecated)" : "");
+    machines = object_class_get_list(TYPE_MACHINE, false);
+    if (type) {
+        ObjectClass *machine_class = OBJECT_CLASS(find_machine(type, machines));
+        if (machine_class) {
+            type_print_class_properties(object_class_get_name(machine_class));
+            return;
         }
-        exit(0);
     }
 
-    mc = find_machine(name, machines);
-    if (!mc) {
-        error_report("unsupported machine type");
-        error_printf("Use -machine help to list supported machines\n");
-        exit(1);
+    printf("Supported machines are:\n");
+    machines = g_slist_sort(machines, machine_class_cmp);
+    for (el = machines; el; el = el->next) {
+        MachineClass *mc = el->data;
+        if (mc->alias) {
+            printf("%-20s %s (alias of %s)\n", mc->alias, mc->desc, mc->name);
+        }
+        printf("%-20s %s%s%s\n", mc->name, mc->desc,
+               mc->is_default ? " (default)" : "",
+               mc->deprecation_reason ? " (deprecated)" : "");
     }
-    return mc;
 }
 
 static const char *pid_file;
@@ -1633,32 +1581,31 @@ static const QEMUOption *lookup_opt(int argc, char **argv,
     return popt;
 }
 
-static MachineClass *select_machine(void)
+static MachineClass *select_machine(QDict *qdict, Error **errp)
 {
+    const char *optarg = qdict_get_try_str(qdict, "type");
     GSList *machines = object_class_get_list(TYPE_MACHINE, false);
-    MachineClass *machine_class = find_default_machine(machines);
-    const char *optarg;
-    QemuOpts *opts;
-    Location loc;
+    MachineClass *machine_class;
+    Error *local_err = NULL;
 
-    loc_push_none(&loc);
-
-    opts = qemu_get_machine_opts();
-    qemu_opts_loc_restore(opts);
-
-    optarg = qemu_opt_get(opts, "type");
     if (optarg) {
-        machine_class = machine_parse(optarg, machines);
+        machine_class = find_machine(optarg, machines);
+        qdict_del(qdict, "type");
+        if (!machine_class) {
+            error_setg(&local_err, "unsupported machine type");
+        }
+    } else {
+        machine_class = find_default_machine(machines);
+        if (!machine_class) {
+            error_setg(&local_err, "No machine specified, and there is no default");
+        }
     }
 
-    if (!machine_class) {
-        error_report("No machine specified, and there is no default");
-        error_printf("Use -machine help to list supported machines\n");
-        exit(1);
-    }
-
-    loc_pop(&loc);
     g_slist_free(machines);
+    if (local_err) {
+        error_append_hint(&local_err, "Use -machine help to list supported machines\n");
+        error_propagate(errp, local_err);
+    }
     return machine_class;
 }
 
@@ -1677,42 +1624,70 @@ static int object_parse_property_opt(Object *obj,
     return 0;
 }
 
-static int machine_set_property(void *opaque,
-                                const char *name, const char *value,
-                                Error **errp)
+/* *Non*recursively replace underscores with dashes in QDict keys.  */
+static void keyval_dashify(QDict *qdict, Error **errp)
 {
-    g_autofree char *qom_name = g_strdup(name);
+    const QDictEntry *ent, *next;
     char *p;
 
-    for (p = qom_name; *p; p++) {
-        if (*p == '_') {
-            *p = '-';
+    for (ent = qdict_first(qdict); ent; ent = next) {
+        g_autofree char *new_key = NULL;
+
+        next = qdict_next(qdict, ent);
+        if (!strchr(ent->key, '_')) {
+            continue;
         }
+        new_key = g_strdup(ent->key);
+        for (p = new_key; *p; p++) {
+            if (*p == '_') {
+                *p = '-';
+            }
+        }
+        if (qdict_haskey(qdict, new_key)) {
+            error_setg(errp, "Conflict between '%s' and '%s'", ent->key, new_key);
+            return;
+        }
+        qobject_ref(ent->value);
+        qdict_put_obj(qdict, new_key, ent->value);
+        qdict_del(qdict, ent->key);
     }
+}
+
+static void qemu_apply_legacy_machine_options(QDict *qdict)
+{
+    const char *value;
+
+    keyval_dashify(qdict, &error_fatal);
 
     /* Legacy options do not correspond to MachineState properties.  */
-    if (g_str_equal(qom_name, "accel")) {
-        return 0;
-    }
-    if (g_str_equal(qom_name, "igd-passthru")) {
-        object_register_sugar_prop(ACCEL_CLASS_NAME("xen"), qom_name, value,
-                                   false);
-        return 0;
-    }
-    if (g_str_equal(qom_name, "kvm-shadow-mem")) {
-        object_register_sugar_prop(ACCEL_CLASS_NAME("kvm"), qom_name, value,
-                                   false);
-        return 0;
-    }
-    if (g_str_equal(qom_name, "kernel-irqchip")) {
-        object_register_sugar_prop(ACCEL_CLASS_NAME("kvm"), qom_name, value,
-                                   false);
-        object_register_sugar_prop(ACCEL_CLASS_NAME("whpx"), qom_name, value,
-                                   false);
-        return 0;
+    value = qdict_get_try_str(qdict, "accel");
+    if (value) {
+        accelerators = g_strdup(value);
+        qdict_del(qdict, "accel");
     }
 
-    return object_parse_property_opt(opaque, name, value, "type", errp);
+    value = qdict_get_try_str(qdict, "igd-passthru");
+    if (value) {
+        object_register_sugar_prop(ACCEL_CLASS_NAME("xen"), "igd-passthru", value,
+                                   false);
+        qdict_del(qdict, "igd-passthru");
+    }
+
+    value = qdict_get_try_str(qdict, "kvm-shadow-mem");
+    if (value) {
+        object_register_sugar_prop(ACCEL_CLASS_NAME("kvm"), "kvm-shadow-mem", value,
+                                   false);
+        qdict_del(qdict, "kvm-shadow-mem");
+    }
+
+    value = qdict_get_try_str(qdict, "kernel-irqchip");
+    if (value) {
+        object_register_sugar_prop(ACCEL_CLASS_NAME("kvm"), "kernel-irqchip", value,
+                                   false);
+        object_register_sugar_prop(ACCEL_CLASS_NAME("whpx"), "kernel-irqchip", value,
+                                   false);
+        qdict_del(qdict, "kernel-irqchip");
+    }
 }
 
 static void object_option_foreach_add(bool (*type_opt_predicate)(const char *))
@@ -1827,16 +1802,14 @@ static bool object_create_early(const char *type)
     return true;
 }
 
-static void qemu_apply_machine_options(void)
+static void qemu_apply_machine_options(QDict *qdict)
 {
     MachineClass *machine_class = MACHINE_GET_CLASS(current_machine);
-    QemuOpts *machine_opts = qemu_get_machine_opts();
     const char *boot_order = NULL;
     const char *boot_once = NULL;
     QemuOpts *opts;
 
-    qemu_opt_foreach(machine_opts, machine_set_property, current_machine,
-                     &error_fatal);
+    object_set_properties_from_keyval(OBJECT(current_machine), qdict, false, &error_fatal);
     current_machine->ram_size = ram_size;
     current_machine->maxram_size = maxram_size;
     current_machine->ram_slots = ram_slots;
@@ -1865,10 +1838,8 @@ static void qemu_apply_machine_options(void)
     current_machine->boot_once = boot_once;
 
     if (semihosting_enabled() && !semihosting_get_argc()) {
-        const char *kernel_filename = qemu_opt_get(machine_opts, "kernel");
-        const char *kernel_cmdline = qemu_opt_get(machine_opts, "append") ?: "";
         /* fall back to the -kernel/-append */
-        semihosting_arg_fallback(kernel_filename, kernel_cmdline);
+        semihosting_arg_fallback(current_machine->kernel_filename, current_machine->kernel_cmdline);
     }
 }
 
@@ -1924,8 +1895,7 @@ static void qemu_create_early_backends(void)
 
     /*
      * Note: we need to create audio and block backends before
-     * machine_set_property(), so machine properties can refer to
-     * them.
+     * setting machine properties, so they can be referred to.
      */
     configure_blockdev(&bdo_queue, machine_class, snapshot);
     audio_init_audiodevs();
@@ -2091,16 +2061,14 @@ static void set_memory_options(MachineClass *mc)
     loc_pop(&loc);
 }
 
-static void qemu_create_machine(MachineClass *machine_class)
+static void qemu_create_machine(QDict *qdict)
 {
+    MachineClass *machine_class = select_machine(qdict, &error_fatal);
     object_set_machine_compat_props(machine_class->compat_props);
 
     set_memory_options(machine_class);
 
     current_machine = MACHINE(object_new_with_class(OBJECT_CLASS(machine_class)));
-    if (machine_help_func(qemu_get_machine_opts(), current_machine)) {
-        exit(0);
-    }
     object_property_add_child(object_get_root(), "machine",
                               OBJECT(current_machine));
     object_property_add_child(container_get(OBJECT(current_machine),
@@ -2131,8 +2099,12 @@ static void qemu_create_machine(MachineClass *machine_class)
      * specified either by the configuration file or by the command line.
      */
     if (machine_class->default_machine_opts) {
-        qemu_opts_set_defaults(qemu_find_opts("machine"),
-                               machine_class->default_machine_opts, 0);
+        QDict *default_opts =
+            keyval_parse(machine_class->default_machine_opts, NULL, NULL,
+                         &error_abort);
+        object_set_properties_from_keyval(OBJECT(current_machine), default_opts,
+                                          false, &error_abort);
+        qobject_unref(default_opts);
     }
 }
 
@@ -2154,7 +2126,8 @@ static int global_init_func(void *opaque, QemuOpts *opts, Error **errp)
  */
 static bool is_qemuopts_group(const char *group)
 {
-    if (g_str_equal(group, "object")) {
+    if (g_str_equal(group, "object") ||
+        g_str_equal(group, "machine")) {
         return false;
     }
     return true;
@@ -2167,6 +2140,13 @@ static void qemu_record_config_group(const char *group, QDict *dict,
         Visitor *v = qobject_input_visitor_new_keyval(QOBJECT(dict));
         object_option_add_visitor(v);
         visit_free(v);
+    } else if (g_str_equal(group, "machine")) {
+        /*
+         * Cannot merge string-valued and type-safe dictionaries, so JSON
+         * is not accepted yet for -M.
+         */
+        assert(!from_json);
+        keyval_merge(machine_opts_dict, dict, errp);
     } else {
         abort();
     }
@@ -2297,13 +2277,11 @@ static int do_configure_accelerator(void *opaque, QemuOpts *opts, Error **errp)
 
 static void configure_accelerators(const char *progname)
 {
-    const char *accelerators;
     bool init_failed = false;
 
     qemu_opts_foreach(qemu_find_opts("icount"),
                       do_configure_icount, NULL, &error_fatal);
 
-    accelerators = qemu_opt_get(qemu_get_machine_opts(), "accel");
     if (QTAILQ_EMPTY(&qemu_accel_opts.head)) {
         char **accel_list, **tmp;
 
@@ -2391,12 +2369,11 @@ static void create_default_memdev(MachineState *ms, const char *path)
                             &error_fatal);
 }
 
-static void qemu_validate_options(void)
+static void qemu_validate_options(const QDict *machine_opts)
 {
-    QemuOpts *machine_opts = qemu_get_machine_opts();
-    const char *kernel_filename = qemu_opt_get(machine_opts, "kernel");
-    const char *initrd_filename = qemu_opt_get(machine_opts, "initrd");
-    const char *kernel_cmdline = qemu_opt_get(machine_opts, "append");
+    const char *kernel_filename = qdict_get_try_str(machine_opts, "kernel");
+    const char *initrd_filename = qdict_get_try_str(machine_opts, "initrd");
+    const char *kernel_cmdline = qdict_get_try_str(machine_opts, "append");
 
     if (kernel_filename == NULL) {
          if (kernel_cmdline != NULL) {
@@ -2736,7 +2713,6 @@ void qemu_init(int argc, char **argv, char **envp)
     qemu_add_opts(&qemu_trace_opts);
     qemu_plugin_add_opts();
     qemu_add_opts(&qemu_option_rom_opts);
-    qemu_add_opts(&qemu_machine_opts);
     qemu_add_opts(&qemu_accel_opts);
     qemu_add_opts(&qemu_mem_opts);
     qemu_add_opts(&qemu_smp_opts);
@@ -2777,6 +2753,7 @@ void qemu_init(int argc, char **argv, char **envp)
         }
     }
 
+    machine_opts_dict = qdict_new();
     if (userconfig) {
         qemu_read_default_config_file(&error_fatal);
     }
@@ -2866,8 +2843,7 @@ void qemu_init(int argc, char **argv, char **envp)
                 parse_display(optarg);
                 break;
             case QEMU_OPTION_nographic:
-                olist = qemu_find_opts("machine");
-                qemu_opts_parse_noisily(olist, "graphics=off", false);
+                qdict_put_str(machine_opts_dict, "graphics", "off");
                 nographic = true;
                 dpy.type = DISPLAY_TYPE_NONE;
                 break;
@@ -2891,16 +2867,16 @@ void qemu_init(int argc, char **argv, char **envp)
                 }
                 break;
             case QEMU_OPTION_kernel:
-                qemu_opts_set(qemu_find_opts("machine"), "kernel", optarg, &error_abort);
+                qdict_put_str(machine_opts_dict, "kernel", optarg);
                 break;
             case QEMU_OPTION_initrd:
-                qemu_opts_set(qemu_find_opts("machine"), "initrd", optarg, &error_abort);
+                qdict_put_str(machine_opts_dict, "initrd", optarg);
                 break;
             case QEMU_OPTION_append:
-                qemu_opts_set(qemu_find_opts("machine"), "append", optarg, &error_abort);
+                qdict_put_str(machine_opts_dict, "append", optarg);
                 break;
             case QEMU_OPTION_dtb:
-                qemu_opts_set(qemu_find_opts("machine"), "dtb", optarg, &error_abort);
+                qdict_put_str(machine_opts_dict, "dtb", optarg);
                 break;
             case QEMU_OPTION_cdrom:
                 drive_add(IF_DEFAULT, 2, optarg, CDROM_OPTS);
@@ -3010,7 +2986,7 @@ void qemu_init(int argc, char **argv, char **envp)
                 }
                 break;
             case QEMU_OPTION_bios:
-                qemu_opts_set(qemu_find_opts("machine"), "firmware", optarg, &error_abort);
+                qdict_put_str(machine_opts_dict, "firmware", optarg);
                 break;
             case QEMU_OPTION_singlestep:
                 singlestep = 1;
@@ -3281,17 +3257,20 @@ void qemu_init(int argc, char **argv, char **envp)
                 preconfig_requested = true;
                 break;
             case QEMU_OPTION_enable_kvm:
-                olist = qemu_find_opts("machine");
-                qemu_opts_parse_noisily(olist, "accel=kvm", false);
+                qdict_put_str(machine_opts_dict, "accel", "kvm");
                 break;
             case QEMU_OPTION_M:
             case QEMU_OPTION_machine:
-                olist = qemu_find_opts("machine");
-                opts = qemu_opts_parse_noisily(olist, optarg, true);
-                if (!opts) {
-                    exit(1);
+                {
+                    bool help;
+
+                    keyval_parse_into(machine_opts_dict, optarg, "type", &help, &error_fatal);
+                    if (help) {
+                        machine_help_func(machine_opts_dict);
+                        exit(EXIT_SUCCESS);
+                    }
+                    break;
                 }
-                break;
             case QEMU_OPTION_accel:
                 accel_opts = qemu_opts_parse_noisily(qemu_find_opts("accel"),
                                                      optarg, true);
@@ -3318,12 +3297,10 @@ void qemu_init(int argc, char **argv, char **envp)
                 }
                 break;
             case QEMU_OPTION_usb:
-                olist = qemu_find_opts("machine");
-                qemu_opts_parse_noisily(olist, "usb=on", false);
+                qdict_put_str(machine_opts_dict, "usb", "on");
                 break;
             case QEMU_OPTION_usbdevice:
-                olist = qemu_find_opts("machine");
-                qemu_opts_parse_noisily(olist, "usb=on", false);
+                qdict_put_str(machine_opts_dict, "usb", "on");
                 add_device_config(DEV_USB, optarg);
                 break;
             case QEMU_OPTION_device:
@@ -3342,12 +3319,10 @@ void qemu_init(int argc, char **argv, char **envp)
                 vnc_parse(optarg);
                 break;
             case QEMU_OPTION_no_acpi:
-                olist = qemu_find_opts("machine");
-                qemu_opts_parse_noisily(olist, "acpi=off", false);
+                qdict_put_str(machine_opts_dict, "acpi", "off");
                 break;
             case QEMU_OPTION_no_hpet:
-                olist = qemu_find_opts("machine");
-                qemu_opts_parse_noisily(olist, "hpet=off", false);
+                qdict_put_str(machine_opts_dict, "hpet", "off");
                 break;
             case QEMU_OPTION_no_reboot:
                 olist = qemu_find_opts("action");
@@ -3600,7 +3575,7 @@ void qemu_init(int argc, char **argv, char **envp)
      */
     loc_set_none();
 
-    qemu_validate_options();
+    qemu_validate_options(machine_opts_dict);
     qemu_process_sugar_options();
 
     /*
@@ -3633,7 +3608,7 @@ void qemu_init(int argc, char **argv, char **envp)
 
     configure_rtc(qemu_find_opts_singleton("rtc"));
 
-    qemu_create_machine(select_machine());
+    qemu_create_machine(machine_opts_dict);
 
     suspend_mux_open();
 
@@ -3641,12 +3616,14 @@ void qemu_init(int argc, char **argv, char **envp)
     qemu_create_default_devices();
     qemu_create_early_backends();
 
-    qemu_apply_machine_options();
+    qemu_apply_legacy_machine_options(machine_opts_dict);
+    qemu_apply_machine_options(machine_opts_dict);
+    qobject_unref(machine_opts_dict);
     phase_advance(PHASE_MACHINE_CREATED);
 
     /*
      * Note: uses machine properties such as kernel-irqchip, must run
-     * after machine_set_property().
+     * after qemu_apply_machine_options.
      */
     configure_accelerators(argv[0]);
     phase_advance(PHASE_ACCEL_CREATED);