chardev: do not use machine_init_done

machine_init_done is not the right flag to check when preconfig
is taken into account; for example "./qemu-system-x86_64 -serial
mon:stdio -preconfig" does not print the QEMU monitor header until after
exit_preconfig.  Add back a custom bool for mux character devices.  This
partially undoes commit c7278b4 ("chardev: introduce chr_machine_done
hook", 2018-03-12), but it keeps the cleaner logic using a function
pointer in ChardevClass.

Reviewed-by: Igor Mammedov <imammedo@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

chardev/char-mux.c

@@ -33,6 +33,13 @@
 
 /* MUX driver for serial I/O splitting */
 
+/*
+ * Set to false by suspend_mux_open.  Open events are delayed until
+ * resume_mux_open.  Usually suspend_mux_open is called before
+ * command line processing and resume_mux_open afterwards.
+ */
+static bool muxes_opened = true;
+
 /* Called with chr_write_lock held.  */
 static int mux_chr_write(Chardev *chr, const uint8_t *buf, int len)
 {
@@ -237,7 +244,7 @@ void mux_chr_send_all_event(Chardev *chr, QEMUChrEvent event)
     MuxChardev *d = MUX_CHARDEV(chr);
     int i;
 
-    if (!machine_init_done) {
+    if (!muxes_opened) {
         return;
     }
 
@@ -328,7 +335,7 @@ static void qemu_chr_open_mux(Chardev *chr,
     /* only default to opened state if we've realized the initial
      * set of muxes
      */
-    *be_opened = machine_init_done;
+    *be_opened = muxes_opened;
     qemu_chr_fe_init(&d->chr, drv, errp);
 }
 
@@ -360,19 +367,42 @@ static void qemu_chr_parse_mux(QemuOpts *opts, ChardevBackend *backend,
  * mux will receive CHR_EVENT_OPENED notifications for the BE
  * immediately.
  */
-static int open_muxes(Chardev *chr)
+static void open_muxes(Chardev *chr)
 {
     /* send OPENED to all already-attached FEs */
     mux_chr_send_all_event(chr, CHR_EVENT_OPENED);
+
     /*
      * mark mux as OPENED so any new FEs will immediately receive
      * OPENED event
      */
     chr->be_open = 1;
+}
+
+void suspend_mux_open(void)
+{
+    muxes_opened = false;
+}
+
+static int chardev_options_parsed_cb(Object *child, void *opaque)
+{
+    Chardev *chr = (Chardev *)child;
+    ChardevClass *class = CHARDEV_GET_CLASS(chr);
+
+    if (!chr->be_open && class->chr_options_parsed) {
+        class->chr_options_parsed(chr);
+    }
 
     return 0;
 }
 
+void resume_mux_open(void)
+{
+    muxes_opened = true;
+    object_child_foreach(get_chardevs_root(),
+                         chardev_options_parsed_cb, NULL);
+}
+
 static void char_mux_class_init(ObjectClass *oc, void *data)
 {
     ChardevClass *cc = CHARDEV_CLASS(oc);
@@ -383,7 +413,7 @@ static void char_mux_class_init(ObjectClass *oc, void *data)
     cc->chr_accept_input = mux_chr_accept_input;
     cc->chr_add_watch = mux_chr_add_watch;
     cc->chr_be_event = mux_chr_be_event;
-    cc->chr_machine_done = open_muxes;
+    cc->chr_options_parsed = open_muxes;
     cc->chr_update_read_handler = mux_chr_update_read_handlers;
 }
 

chardev/meson.build

@@ -25,7 +25,7 @@ chardev_ss.add(when: 'CONFIG_WIN32', if_true: files(
 
 chardev_ss = chardev_ss.apply(config_host, strict: false)
 
-softmmu_ss.add(files('chardev-sysemu.c', 'msmouse.c', 'wctablet.c', 'testdev.c'))
+softmmu_ss.add(files('msmouse.c', 'wctablet.c', 'testdev.c'))
 
 chardev_modules = {}
 

hw/core/machine.c

@@ -1179,7 +1179,7 @@ void machine_run_board_init(MachineState *machine)
 static NotifierList machine_init_done_notifiers =
     NOTIFIER_LIST_INITIALIZER(machine_init_done_notifiers);
 
-bool machine_init_done;
+static bool machine_init_done;
 
 void qemu_add_machine_init_done_notifier(Notifier *notify)
 {

include/chardev/char.h

@@ -270,8 +270,7 @@ struct ChardevClass {
     void (*chr_set_echo)(Chardev *chr, bool echo);
     void (*chr_set_fe_open)(Chardev *chr, int fe_open);
     void (*chr_be_event)(Chardev *s, QEMUChrEvent event);
-    /* Return 0 if succeeded, 1 if failed */
-    int (*chr_machine_done)(Chardev *chr);
+    void (*chr_options_parsed)(Chardev *chr);
 };
 
 Chardev *qemu_chardev_new(const char *id, const char *typename,
@@ -283,6 +282,9 @@ extern int term_escape_char;
 GSource *qemu_chr_timeout_add_ms(Chardev *chr, guint ms,
                                  GSourceFunc func, void *private);
 
+void suspend_mux_open(void);
+void resume_mux_open(void);
+
 /* console.c */
 void qemu_chr_parse_vc(QemuOpts *opts, ChardevBackend *backend, Error **errp);
 

include/sysemu/sysemu.h

@@ -16,8 +16,6 @@ extern bool qemu_uuid_set;
 void qemu_add_exit_notifier(Notifier *notify);
 void qemu_remove_exit_notifier(Notifier *notify);
 
-extern bool machine_init_done;
-
 void qemu_run_machine_init_done_notifiers(void);
 void qemu_add_machine_init_done_notifier(Notifier *notify);
 void qemu_remove_machine_init_done_notifier(Notifier *notify);

softmmu/vl.c

@@ -3462,6 +3462,8 @@ void qemu_init(int argc, char **argv, char **envp)
 
     qemu_create_machine(select_machine());
 
+    suspend_mux_open();
+
     qemu_disable_default_devices();
     qemu_create_default_devices();
     qemu_create_early_backends();
@@ -3525,4 +3527,5 @@ void qemu_init(int argc, char **argv, char **envp)
     }
     accel_setup_post(current_machine);
     os_setup_post();
+    resume_mux_open();
 }

stubs/meson.build

@@ -21,7 +21,6 @@ stub_ss.add(files('iothread-lock.c'))
 stub_ss.add(files('isa-bus.c'))
 stub_ss.add(files('is-daemonized.c'))
 stub_ss.add(when: 'CONFIG_LINUX_AIO', if_true: files('linux-aio.c'))
-stub_ss.add(files('machine-init-done.c'))
 stub_ss.add(files('migr-blocker.c'))
 stub_ss.add(files('monitor.c'))
 stub_ss.add(files('monitor-core.c'))