diff --git a/src/intel/vulkan/genX_gpu_memcpy.c b/src/intel/vulkan/genX_gpu_memcpy.c
index eaafcfa3b22..a8e99d1a695 100644
--- a/src/intel/vulkan/genX_gpu_memcpy.c
+++ b/src/intel/vulkan/genX_gpu_memcpy.c
@@ -224,7 +224,7 @@ genX(cmd_buffer_so_memcpy)(struct anv_cmd_buffer *cmd_buffer,
 
 #if GEN_GEN >= 8
       sob.SOBufferEnable = true;
-      sob.SurfaceSize = size - 1;
+      sob.SurfaceSize = size / 4 - 1;
 #else
       sob.SurfacePitch = bs;
       sob.SurfaceEndAddress = sob.SurfaceBaseAddress;