drm/i915/gvt: let force_to_nonpriv cmd handler only valid for LRI cmd

the cmd_reg_handler() is called by cmds LRM, PIPE_CTRL, SRM...
for LRM, SRM, we cannot get write data in a simple way.
On other side,  the force_to_nonpriv reigsters will only be written in LRI
in current drivers. so we don't want to bother the handler to handle those
memory access cmds, just leave a print message here.
Signed-off-by: Zhao Yan <yan.y.zhao@intel.com>
Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>

drivers/gpu/drm/i915/gvt/cmd_parser.c

@@ -813,14 +813,22 @@ static inline bool is_force_nonpriv_mmio(unsigned int offset)
 }
 
 static int force_nonpriv_reg_handler(struct parser_exec_state *s,
-				     unsigned int offset, unsigned int index)
+		unsigned int offset, unsigned int index, char *cmd)
 {
 	struct intel_gvt *gvt = s->vgpu->gvt;
-	unsigned int data = cmd_val(s, index + 1);
+	unsigned int data;
 	u32 ring_base;
 	u32 nopid;
 	struct drm_i915_private *dev_priv = s->vgpu->gvt->dev_priv;
 
+	if (!strcmp(cmd, "lri"))
+		data = cmd_val(s, index + 1);
+	else {
+		gvt_err("Unexpected forcenonpriv 0x%x write from cmd %s\n",
+			offset, cmd);
+		return -EINVAL;
+	}
+
 	ring_base = dev_priv->engine[s->ring_id]->mmio_base;
 	nopid = i915_mmio_reg_offset(RING_NOPID(ring_base));
 
@@ -877,7 +885,7 @@ static int cmd_reg_handler(struct parser_exec_state *s,
 		return -EINVAL;
 
 	if (is_force_nonpriv_mmio(offset) &&
-		force_nonpriv_reg_handler(s, offset, index))
+		force_nonpriv_reg_handler(s, offset, index, cmd))
 		return -EPERM;
 
 	if (offset == i915_mmio_reg_offset(DERRMR) ||