The function CheckFeatureSupported() is used as an EFI_AP_PROCEDURE in the MP Services Protocol service StartAllAPs(). Any function used as an EFI_AP_PROCEDURE must use EFIAPI calling convention. Cc: Laszlo Ersek <lersek@redhat.com> Cc: Jeff Fan <jeff.fan@intel.com> Cc: Jiewen Yao <jiewen.yao@intel.com> Contributed-under: TianoCore Contribution Agreement 1.0 Signed-off-by: Michael Kinney <michael.d.kinney@intel.com> Reviewed-by: Jeff Fan <jeff.fan@intel.com> Reviewed-by: Laszlo Ersek <lersek@redhat.com> Reviewed-by: Jiewen Yao <jiewen.yao@intel.com>