ui: Create sync objects and fences only for blobs

Create sync objects and fences only for dmabufs that are blobs. Once a
fence is created (after glFlush) and is signalled,
graphic_hw_gl_flushed() will be called and virtio-gpu cmd processing
will be resumed.

Cc: Gerd Hoffmann <kraxel@redhat.com>
Signed-off-by: Vivek Kasireddy <vivek.kasireddy@intel.com>
Message-Id: <20210914211837.3229977-4-vivek.kasireddy@intel.com>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>

include/ui/console.h

@@ -170,6 +170,7 @@ typedef struct QemuDmaBuf {
     bool      y0_top;
     void      *sync;
     int       fence_fd;
+    bool      allow_fences;
 } QemuDmaBuf;
 
 typedef struct DisplayState DisplayState;

include/ui/egl-helpers.h

@@ -19,6 +19,7 @@ typedef struct egl_fb {
     GLuint texture;
     GLuint framebuffer;
     bool delete_texture;
+    QemuDmaBuf *dmabuf;
 } egl_fb;
 
 void egl_fb_destroy(egl_fb *fb);

include/ui/gtk.h

@@ -155,6 +155,7 @@ extern bool gtk_use_gl_area;
 /* ui/gtk.c */
 void gd_update_windowsize(VirtualConsole *vc);
 int gd_monitor_update_interval(GtkWidget *widget);
+void gd_hw_gl_flushed(void *vc);
 
 /* ui/gtk-egl.c */
 void gd_egl_init(VirtualConsole *vc);