console: add graphic_console_set_hwops

Add a function to allow display emulations to switch the hwops
function pointers.  This is useful for devices which have two
completely different operation modes.  Typical case is the vga
compatibility mode vs. native mode in qxl and the upcoming
virtio-vga device.
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>

include/ui/console.h

@@ -292,6 +292,9 @@ typedef struct GraphicHwOps {
 QemuConsole *graphic_console_init(DeviceState *dev, uint32_t head,
                                   const GraphicHwOps *ops,
                                   void *opaque);
+void graphic_console_set_hwops(QemuConsole *con,
+                               const GraphicHwOps *hw_ops,
+                               void *opaque);
 
 void graphic_hw_update(QemuConsole *con);
 void graphic_hw_invalidate(QemuConsole *con);

ui/console.c

@@ -1677,6 +1677,14 @@ DisplayState *init_displaystate(void)
     return display_state;
 }
 
+void graphic_console_set_hwops(QemuConsole *con,
+                               const GraphicHwOps *hw_ops,
+                               void *opaque)
+{
+    con->hw_ops = hw_ops;
+    con->hw = opaque;
+}
+
 QemuConsole *graphic_console_init(DeviceState *dev, uint32_t head,
                                   const GraphicHwOps *hw_ops,
                                   void *opaque)
@@ -1691,8 +1699,7 @@ QemuConsole *graphic_console_init(DeviceState *dev, uint32_t head,
     ds = get_alloc_displaystate();
     trace_console_gfx_new();
     s = new_console(ds, GRAPHIC_CONSOLE, head);
-    s->hw_ops = hw_ops;
-    s->hw = opaque;
+    graphic_console_set_hwops(s, hw_ops, opaque);
     if (dev) {
         object_property_set_link(OBJECT(s), OBJECT(dev), "device",
                                  &error_abort);