[PATCH v1 5/5] virtio-gpu: Make resource_flush wait on the sync object for blobs

[Vivek Kasireddy]

To make sure that the Guest would not use the backing storage
associated with a blob resource before or at the same time when
the Host does a blit with it, resource_flush needs to wait on
the sync object associated with the blob. Doing this would prevent
tearing/flickering or other issues when using blob resources.

Cc: Gerd Hoffmann <kraxel@redhat.com>
Signed-off-by: Vivek Kasireddy <vivek.kasireddy@intel.com>
Signed-off-by: Dongwon Kim <dongwon.kim@intel.com>
---
 hw/display/virtio-gpu-udmabuf.c | 28 ++++++++++++++++++++++++++++
 hw/display/virtio-gpu.c         |  1 +
 include/hw/virtio/virtio-gpu.h  |  2 ++
 3 files changed, 31 insertions(+)

diff --git a/hw/display/virtio-gpu-udmabuf.c b/hw/display/virtio-gpu-udmabuf.c
index 33e329e8aa..8c1b6f8763 100644
--- a/hw/display/virtio-gpu-udmabuf.c
+++ b/hw/display/virtio-gpu-udmabuf.c
@@ -167,6 +167,34 @@ static void virtio_gpu_free_dmabuf(VirtIOGPU *g, 
VGPUDMABuf *dmabuf)
     g_free(dmabuf);
 }
 
+static VGPUDMABuf
+*virtio_gpu_find_dmabuf(VirtIOGPU *g,
+                        struct virtio_gpu_simple_resource *res)
+{
+    VGPUDMABuf *dmabuf, *tmp;
+
+    QTAILQ_FOREACH_SAFE(dmabuf, &g->dmabuf.bufs, next, tmp) {
+        if (dmabuf->buf.fd == res->dmabuf_fd) {
+            return dmabuf;
+        }
+    }
+
+    return NULL;
+}
+
+void virtio_gpu_resource_wait_sync(VirtIOGPU *g,
+                                   struct virtio_gpu_simple_resource *res)
+{
+    struct virtio_gpu_scanout *scanout;
+    VGPUDMABuf *dmabuf;
+
+    dmabuf = virtio_gpu_find_dmabuf(g, res);
+    if (dmabuf && dmabuf->buf.sync) {
+        scanout = &g->parent_obj.scanout[dmabuf->scanout_id];
+        dpy_gl_wait_dmabuf(scanout->con, &dmabuf->buf);
+    }
+}
+
 static VGPUDMABuf
 *virtio_gpu_create_dmabuf(VirtIOGPU *g,
                           uint32_t scanout_id,
diff --git a/hw/display/virtio-gpu.c b/hw/display/virtio-gpu.c
index 4d549377cb..dd037137e9 100644
--- a/hw/display/virtio-gpu.c
+++ b/hw/display/virtio-gpu.c
@@ -523,6 +523,7 @@ static void virtio_gpu_resource_flush(VirtIOGPU *g,
                 console_has_gl(scanout->con)) {
                 dpy_gl_update(scanout->con, 0, 0, scanout->width,
                               scanout->height);
+                virtio_gpu_resource_wait_sync(g, res);
                 return;
             }
         }
diff --git a/include/hw/virtio/virtio-gpu.h b/include/hw/virtio/virtio-gpu.h
index bcf54d970f..9b9b499d06 100644
--- a/include/hw/virtio/virtio-gpu.h
+++ b/include/hw/virtio/virtio-gpu.h
@@ -274,6 +274,8 @@ int virtio_gpu_update_dmabuf(VirtIOGPU *g,
                              uint32_t scanout_id,
                              struct virtio_gpu_simple_resource *res,
                              struct virtio_gpu_framebuffer *fb);
+void virtio_gpu_resource_wait_sync(VirtIOGPU *g,
+                                   struct virtio_gpu_simple_resource *res);
 
 /* virtio-gpu-3d.c */
 void virtio_gpu_virgl_process_cmd(VirtIOGPU *g,
-- 
2.30.2