If CR0 PG bit is not set, it means paging is not enabled on BSP. Thus, Execute Disable feature is not working actually. Thus, we cannot enable it on APs. v2: Correct the commit log. Cc: Feng Tian <feng.tian@intel.com> Cc: Michael Kinney <michael.d.kinney@intel.com> Contributed-under: TianoCore Contribution Agreement 1.0 Signed-off-by: Jeff Fan <jeff.fan@intel.com> Reviewed-by: Feng Tian <feng.tian@intel.com>