REF: https://bugzilla.tianocore.org/show_bug.cgi?id=3962 Two SMM variables (mSmrrSupported & mSmmFeatureControlSupported) are global variables, they control whether the SMRR and SMM Feature Control MSR will be restored respectively. To avoid the TOCTOU, add PCD to control SMRR & SmmFeatureControl enable. Cc: Eric Dong <eric.dong@intel.com> Reviewed-by: Ray Ni <ray.ni@intel.com> Cc: Star Zeng <star.zeng@intel.com> Cc: Michael D Kinney <michael.d.kinney@intel.com> Signed-off-by: Jiaxin Wu <jiaxin.wu@intel.com>