virtio-gpu-3d: fix memory leak in resource attach backing

If the virgl_renderer_resource_attach_iov function fails the
'res_iovs' will be leaked. Add check of the return value to
free the 'res_iovs' when failing.
Signed-off-by: NLi Qiang <liq3ea@gmail.com>
Reviewed-by: NMarc-André Lureau <marcandre.lureau@redhat.com>
Message-id: 1482999086-59795-1-git-send-email-liq3ea@gmail.com
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>

hw/display/virtio-gpu-3d.c

@@ -291,8 +291,11 @@ static void virgl_resource_attach_backing(VirtIOGPU *g,
         return;
     }
 
-    virgl_renderer_resource_attach_iov(att_rb.resource_id,
-                                       res_iovs, att_rb.nr_entries);
+    ret = virgl_renderer_resource_attach_iov(att_rb.resource_id,
+                                             res_iovs, att_rb.nr_entries);
+
+    if (ret != 0)
+        virtio_gpu_cleanup_mapping_iov(res_iovs, att_rb.nr_entries);
 }
 
 static void virgl_resource_detach_backing(VirtIOGPU *g,