Configuration of Intel TXT register, following the guide:
Intel® Trusted Execution Technology: Software Development Guide Measured Launched Environment Developer’s Guide August 2016 Revision 013
from https://web.archive.org/web/20170506220426/https://www.intel.com/content/www/us/en/software-developers/intel-txt-software-development-guide.html (and https://usermanual.wiki/Document/inteltxtsoftwaredevelopmentguide.1721028921 )
Appendix B.1. (Intel® TXT Configuration Registers) details:
These registers are mapped into two regions of memory, representing the public and private configuration spaces. […] The private space registers are mapped to the address range starting at FED20000H. The public space registers are mapped to the address range starting at FED30000H.
As chipsec usually runs in environments where the private space is not available, only the public space registers were described here.