# TxtDxe
**Index**: 0064 | **Size**: 31168 bytes | **Arch**: x64 | **Phase**: DXE

## Overview
Intel Trusted Execution Technology (TXT / LaGrande Technology) DXE driver for Purley/CoffeeLake Xeon platforms. Manages measured launch by locating the BIOS Authenticated Code Module (ACM) address from platform HOBs, setting up MTRRs and machine check banks, launching the ACM in a special environment, and handling ACM errors. Installs the TXT DXE Protocol for SMM and boot script coordination.

## Key Functions
- `TxtDxeLaunchBiosAcm` -- Disables MC banks, sends SIPI to APs, calls assembly ACM launch, restores state
- `PlatformLaunchBiosAcm` -- Assembly-level ACM launch wrapper configuring GDT/IDT/MTRRs/MCG
- `HandleAcmError` -- Decision tree for ACM errors: ignore, clear LT/TPM CMOS state, or trigger reset
- `ConfigureMachineCheckBanks` -- Saves/restores IA32_MC9-MC11 CTL and MCG_CONTAIN for ACM launch
- `InstallTxtDxeProtocol` -- Installs TXT DXE protocol into UEFI protocol database

## Protocols / Dependencies
- TXT Device Memory Policy HOB, TXT Platform Policy HOB
- MP Services Protocol (AP management and APIC ID table)
- SMM Communication Protocol, SMM Base2 Protocol, SMM LockBox Protocol
- MM PCI User Access Protocol, PCD Protocol

## Platform
HR650X, Intel TXT (Server TXT), BIOS ACM launch, LCP policy data, SINIT memory region management