# RuntimeMemoryHole

| Field   | Value                    |
|---------|--------------------------|
| Index   | 238                      |
| Module  | RuntimeMemoryHole        |
| Size    | 6,400 bytes              |
| Phase   | Other (DXE runtime utility) |

## Overview

RuntimeMemoryHole is a UEFI DXE module that manages the runtime memory hole configuration, programming memory-mapped I/O (MMIO) and reserved memory ranges required for system stability after boot services are exited. It configures the memory controller to reserve specific address ranges for system management and platform-specific hardware, ensuring these regions remain accessible during OS runtime.

## Key Functions

- **ModuleEntryPoint**: Entry point that initializes and applies the runtime memory hole configuration.
- **sub_44C**: Memory hole policy initialization and register programming preparation.
- **sub_58C**: Core memory hole programming, applying reserved address range configuration to hardware.

## Dependencies

- UEFI system table and boot services
- Memory controller configuration registers
- Platform memory policy HOBs and data tables
- PCI configuration space access

## Platform

HR650X server platform, x64 architecture. Runs during DXE phase and installs runtime services for OS-accessible memory hole configuration.