Compatible SMM memory (SMRAM) Protection check module This CHIPSEC module simply reads SMRAMC and checks that D_LCK is set.
Reference: In 2006, Security Issues Related to Pentium System Management Mode outlined a configuration issue where compatibility SMRAM was not locked on some platforms. This means that ring 0 software was able to modify System Management Mode (SMM) code and data that should have been protected.
In Compatability SMRAM (CSEG), access to memory is defined by the SMRAMC register. When SMRAMC[D_LCK] is not set by the BIOS, SMRAM can be accessed even when the CPU is not in SMM. Such attacks were also described in Using CPU SMM to Circumvent OS Security Functions and Using SMM for Other Purposes.
chipsec_main -m common.smm
>>> chipsec_main.py -m common.smm
This module will only run on client (core) platforms that have PCI0.0.0_SMRAMC defined.