virtio-gpu: Make non-gl display updates work again when blob=true

In the case where the console does not have gl capability, and
if blob is set to true, make sure that the display updates still
work. Commit e86a93f accidentally broke this by misplacing
the return statement (in resource_flush) causing the updates to
be silently ignored.

Fixes: e86a93f ("virtio-gpu: splitting one extended mode guest fb into n-scanouts")
Cc: Gerd Hoffmann <kraxel@redhat.com>
Cc: Marc-André Lureau <marcandre.lureau@redhat.com>
Cc: Dongwon Kim <dongwon.kim@intel.com>
Signed-off-by: Vivek Kasireddy <vivek.kasireddy@intel.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-ID: <20230623060454.3749910-1-vivek.kasireddy@intel.com>

hw/display/virtio-gpu.c

@@ -498,6 +498,8 @@ static void virtio_gpu_resource_flush(VirtIOGPU *g,
     struct virtio_gpu_resource_flush rf;
     struct virtio_gpu_scanout *scanout;
     pixman_region16_t flush_region;
+    bool within_bounds = false;
+    bool update_submitted = false;
     int i;
 
     VIRTIO_GPU_FILL_CMD(rf);
@@ -518,13 +520,28 @@ static void virtio_gpu_resource_flush(VirtIOGPU *g,
                 rf.r.x < scanout->x + scanout->width &&
                 rf.r.x + rf.r.width >= scanout->x &&
                 rf.r.y < scanout->y + scanout->height &&
-                rf.r.y + rf.r.height >= scanout->y &&
-                console_has_gl(scanout->con)) {
-                dpy_gl_update(scanout->con, 0, 0, scanout->width,
-                              scanout->height);
+                rf.r.y + rf.r.height >= scanout->y) {
+                within_bounds = true;
+
+                if (console_has_gl(scanout->con)) {
+                    dpy_gl_update(scanout->con, 0, 0, scanout->width,
+                                  scanout->height);
+                    update_submitted = true;
+                }
             }
         }
-        return;
+
+        if (update_submitted) {
+            return;
+        }
+        if (!within_bounds) {
+            qemu_log_mask(LOG_GUEST_ERROR, "%s: flush bounds outside scanouts"
+                          " bounds for flush %d: %d %d %d %d\n",
+                          __func__, rf.resource_id, rf.r.x, rf.r.y,
+                          rf.r.width, rf.r.height);
+            cmd->error = VIRTIO_GPU_RESP_ERR_INVALID_PARAMETER;
+            return;
+        }
     }
 
     if (!res->blob &&