ui/vnc: Do not use console_select()

console_select() is shared by other displays and a console_select() call
from one of them triggers console switching also in ui/curses,
circumventing key state reinitialization that needs to be performed in
preparation and resulting in stuck keys.

Use its internal state to track the current active console to prevent
such a surprise console switch.

Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <20240319-console-v2-2-3fd6feef321a@daynix.com>

include/ui/console.h

@@ -413,6 +413,7 @@ void qemu_console_early_init(void);
 
 void qemu_console_set_display_gl_ctx(QemuConsole *con, DisplayGLCtx *ctx);
 
+QemuConsole *qemu_console_lookup_default(void);
 QemuConsole *qemu_console_lookup_by_index(unsigned int index);
 QemuConsole *qemu_console_lookup_by_device(DeviceState *dev, uint32_t head);
 QemuConsole *qemu_console_lookup_by_device_name(const char *device_id,

include/ui/kbd-state.h

@@ -99,4 +99,15 @@ bool qkbd_state_modifier_get(QKbdState *kbd, QKbdModifier mod);
  */
 void qkbd_state_lift_all_keys(QKbdState *kbd);
 
+/**
+ * qkbd_state_switch_console: Switch console.
+ *
+ * This sends key up events to the previous console for all keys which are in
+ * down state to prevent keys being stuck, and remembers the new console.
+ *
+ * @kbd: state tracker state.
+ * @con: new QemuConsole for this state tracker.
+ */
+void qkbd_state_switch_console(QKbdState *kbd, QemuConsole *con);
+
 #endif /* QEMU_UI_KBD_STATE_H */

ui/console.c

@@ -1325,6 +1325,18 @@ void graphic_console_close(QemuConsole *con)
     dpy_gfx_replace_surface(con, surface);
 }
 
+QemuConsole *qemu_console_lookup_default(void)
+{
+    QemuConsole *con;
+
+    QTAILQ_FOREACH(con, &consoles, next) {
+        if (QEMU_IS_GRAPHIC_CONSOLE(con)) {
+            return con;
+        }
+    }
+    return QTAILQ_FIRST(&consoles);
+}
+
 QemuConsole *qemu_console_lookup_by_index(unsigned int index)
 {
     QemuConsole *con;

ui/kbd-state.c

@@ -117,6 +117,12 @@ void qkbd_state_lift_all_keys(QKbdState *kbd)
     }
 }
 
+void qkbd_state_switch_console(QKbdState *kbd, QemuConsole *con)
+{
+    qkbd_state_lift_all_keys(kbd);
+    kbd->con = con;
+}
+
 void qkbd_state_set_delay(QKbdState *kbd, int delay_ms)
 {
     kbd->key_delay_ms = delay_ms;

ui/vnc.c

@@ -1872,12 +1872,16 @@ static void do_key_event(VncState *vs, int down, int keycode, int sym)
     /* QEMU console switch */
     switch (qcode) {
     case Q_KEY_CODE_1 ... Q_KEY_CODE_9: /* '1' to '9' keys */
-        if (vs->vd->dcl.con == NULL && down &&
+        if (down &&
             qkbd_state_modifier_get(vs->vd->kbd, QKBD_MOD_CTRL) &&
             qkbd_state_modifier_get(vs->vd->kbd, QKBD_MOD_ALT)) {
-            /* Reset the modifiers sent to the current console */
-            qkbd_state_lift_all_keys(vs->vd->kbd);
-            console_select(qcode - Q_KEY_CODE_1);
+            QemuConsole *con = qemu_console_lookup_by_index(qcode - Q_KEY_CODE_1);
+            if (con) {
+                unregister_displaychangelistener(&vs->vd->dcl);
+                qkbd_state_switch_console(vs->vd->kbd, con);
+                vs->vd->dcl.con = con;
+                register_displaychangelistener(&vs->vd->dcl);
+            }
             return;
         }
     default:
@@ -4206,7 +4210,7 @@ void vnc_display_open(const char *id, Error **errp)
             goto fail;
         }
     } else {
-        con = NULL;
+        con = qemu_console_lookup_default();
     }
 
     if (con != vd->dcl.con) {