diff --git a/src/mapi/glapi/gen/gl_API.xml b/src/mapi/glapi/gen/gl_API.xml
index bc59ddc759a..874ec8dd552 100644
--- a/src/mapi/glapi/gen/gl_API.xml
+++ b/src/mapi/glapi/gen/gl_API.xml
@@ -12936,14 +12936,7 @@
     </function>
 
     <function name="DrawElementsUserBuf" es1="1.0" es2="2.0" marshal="custom">
-        <param name="indexBuf" type="GLintptr"/> <!-- "struct gl_buffer_object *" really -->
-        <param name="mode" type="GLenum"/>
-        <param name="count" type="GLsizei"/>
-        <param name="type" type="GLenum"/>
-        <param name="indices" type="const GLvoid *"/>
-        <param name="instancecount" type="GLsizei"/>
-        <param name="basevertex" type="GLint"/>
-        <param name="baseinstance" type="GLuint"/>
+        <param name="cmd" type="const GLvoid *"/> <!-- struct marshal_cmd_DrawElementsUserBuf -->
     </function>
 
     <function name="MultiDrawArraysUserBuf" es1="1.0" es2="2.0" marshal="custom">
diff --git a/src/mesa/main/draw.c b/src/mesa/main/draw.c
index 8519bd55244..0004cff184d 100644
--- a/src/mesa/main/draw.c
+++ b/src/mesa/main/draw.c
@@ -42,6 +42,7 @@
 #include "transformfeedback.h"
 #include "pipe/p_state.h"
 #include "api_exec_decl.h"
+#include "glthread_marshal.h"
 
 #include "state_tracker/st_context.h"
 #include "state_tracker/st_draw.h"
@@ -1983,10 +1984,7 @@ _mesa_DrawElementsInstancedBaseVertexBaseInstance(GLenum mode,
  * GL_ELEMENT_ARRAY_BUFFER if indexBuf != NULL.
  */
 void GLAPIENTRY
-_mesa_DrawElementsUserBuf(GLintptr indexBuf, GLenum mode,
-                          GLsizei count, GLenum type,
-                          const GLvoid *indices, GLsizei numInstances,
-                          GLint basevertex, GLuint baseInstance)
+_mesa_DrawElementsUserBuf(const GLvoid *ptr)
 {
    GET_CURRENT_CONTEXT(ctx);
    FLUSH_FOR_DRAW(ctx);
@@ -1996,19 +1994,31 @@ _mesa_DrawElementsUserBuf(GLintptr indexBuf, GLenum mode,
    if (ctx->NewState)
       _mesa_update_state(ctx);
 
+   const struct marshal_cmd_DrawElementsUserBuf *cmd =
+      (const struct marshal_cmd_DrawElementsUserBuf *)ptr;
+   const GLenum mode = cmd->mode;
+   const GLsizei count = cmd->count;
+   const GLenum type = cmd->type;
+   const GLsizei instance_count = cmd->instance_count;
+
    if (!_mesa_is_no_error_enabled(ctx) &&
        !_mesa_validate_DrawElementsInstanced(ctx, mode, count, type,
-                                             numInstances))
+                                             instance_count))
       return;
 
    struct gl_buffer_object *index_bo =
-      indexBuf ? (struct gl_buffer_object*)indexBuf :
-                 ctx->Array.VAO->IndexBufferObj;
+      cmd->index_buffer ? cmd->index_buffer : ctx->Array.VAO->IndexBufferObj;
 
+   const GLvoid *indices = cmd->indices;
+   const GLint basevertex = cmd->basevertex;
+   const GLuint baseinstance = cmd->baseinstance;
+
+   ctx->DrawID = cmd->drawid;
    _mesa_validated_drawrangeelements(ctx, index_bo,
                                      mode, false, 0, ~0,
                                      count, type, indices, basevertex,
-                                     numInstances, baseInstance);
+                                     instance_count, baseinstance);
+   ctx->DrawID = 0;
 }
 
 
diff --git a/src/mesa/main/glthread_draw.c b/src/mesa/main/glthread_draw.c
index 746aa6860d9..e362b428745 100644
--- a/src/mesa/main/glthread_draw.c
+++ b/src/mesa/main/glthread_draw.c
@@ -707,21 +707,6 @@ _mesa_unmarshal_DrawElementsInstancedBaseVertexBaseInstanceDrawID(struct gl_cont
    return cmd_size;
 }
 
-struct marshal_cmd_DrawElementsUserBuf
-{
-   struct marshal_cmd_base cmd_base;
-   GLenum16 mode;
-   GLenum16 type;
-   GLsizei count;
-   GLsizei instance_count;
-   GLint basevertex;
-   GLuint baseinstance;
-   GLuint drawid;
-   GLuint user_buffer_mask;
-   const GLvoid *indices;
-   struct gl_buffer_object *index_buffer;
-};
-
 uint32_t
 _mesa_unmarshal_DrawElementsUserBuf(struct gl_context *ctx,
                                     const struct marshal_cmd_DrawElementsUserBuf *restrict cmd)
@@ -735,21 +720,9 @@ _mesa_unmarshal_DrawElementsUserBuf(struct gl_context *ctx,
       _mesa_InternalBindVertexBuffers(ctx, buffers, user_buffer_mask);
 
    /* Draw. */
-   const GLenum mode = cmd->mode;
-   const GLsizei count = cmd->count;
-   const GLenum type = cmd->type;
-   const GLvoid *indices = cmd->indices;
-   const GLsizei instance_count = cmd->instance_count;
-   const GLint basevertex = cmd->basevertex;
-   const GLuint baseinstance = cmd->baseinstance;
-   struct gl_buffer_object *index_buffer = cmd->index_buffer;
+   CALL_DrawElementsUserBuf(ctx->Dispatch.Current, (cmd));
 
-   ctx->DrawID = cmd->drawid;
-   CALL_DrawElementsUserBuf(ctx->Dispatch.Current,
-                            ((GLintptr)index_buffer, mode, count, type,
-                             indices, instance_count, basevertex,
-                             baseinstance));
-   ctx->DrawID = 0;
+   struct gl_buffer_object *index_buffer = cmd->index_buffer;
    _mesa_reference_buffer_object(ctx, &index_buffer, NULL);
    return cmd->cmd_base.cmd_size;
 }
@@ -1803,10 +1776,7 @@ _mesa_marshal_DrawArraysUserBuf(void)
 }
 
 void GLAPIENTRY
-_mesa_marshal_DrawElementsUserBuf(GLintptr indexBuf, GLenum mode,
-                                  GLsizei count, GLenum type,
-                                  const GLvoid *indices, GLsizei numInstances,
-                                  GLint basevertex, GLuint baseInstance)
+_mesa_marshal_DrawElementsUserBuf(const GLvoid *cmd)
 {
    unreachable("should never end up here");
 }
diff --git a/src/mesa/main/glthread_marshal.h b/src/mesa/main/glthread_marshal.h
index 512800020f6..3560754d39d 100644
--- a/src/mesa/main/glthread_marshal.h
+++ b/src/mesa/main/glthread_marshal.h
@@ -55,6 +55,21 @@ typedef uint32_t (*_mesa_unmarshal_func)(struct gl_context *ctx,
                                          const void *restrict cmd);
 extern const _mesa_unmarshal_func _mesa_unmarshal_dispatch[NUM_DISPATCH_CMD];
 
+struct marshal_cmd_DrawElementsUserBuf
+{
+   struct marshal_cmd_base cmd_base;
+   GLenum16 mode;
+   GLenum16 type;
+   GLsizei count;
+   GLsizei instance_count;
+   GLint basevertex;
+   GLuint baseinstance;
+   GLuint drawid;
+   GLuint user_buffer_mask;
+   const GLvoid *indices;
+   struct gl_buffer_object *index_buffer;
+};
+
 static inline void *
 _mesa_glthread_allocate_command(struct gl_context *ctx,
                                 uint16_t cmd_id,