diff --git a/src/gfxstream/guest/platform/include/virtgpu_gfxstream_protocol.h b/src/gfxstream/guest/platform/include/virtgpu_gfxstream_protocol.h
index 2edc2f30d26..c618ddc93ee 100644
--- a/src/gfxstream/guest/platform/include/virtgpu_gfxstream_protocol.h
+++ b/src/gfxstream/guest/platform/include/virtgpu_gfxstream_protocol.h
@@ -42,6 +42,7 @@
 #define GFXSTREAM_CREATE_IMPORT_SYNC_VK         0xa001
 #define GFXSTREAM_CREATE_QSRI_EXPORT_VK         0xa002
 #define GFXSTREAM_RESOURCE_CREATE_3D            0xa003
+#define GFXSTREAM_ACQUIRE_SYNC                  0xa004
 
 // clang-format off
 // A placeholder command to ensure virtio-gpu completes
@@ -104,6 +105,12 @@ struct gfxstreamResourceCreate3d {
     uint64_t blobId;
 };
 
+struct gfxstreamAcquireSync {
+    struct gfxstreamHeader hdr;
+    uint32_t padding;
+    uint64_t syncId;
+};
+
 struct vulkanCapset {
     uint32_t protocolVersion;
 
@@ -116,7 +123,8 @@ struct vulkanCapset {
     uint32_t blobAlignment;
     uint32_t noRenderControlEnc;
     uint32_t alwaysBlob;
-    uint32_t padding[13];
+    uint32_t externalSync;
+    uint32_t padding[12];
 };
 
 struct magmaCapset {