Introduction

This document describes the software interfaces for Itanium® architecture-based processors which support VT-i (Intel® Virtualization Technology for the Intel® Itanium® architecture). These additions allow for the virtualization of processor hardware in order to allow multiple instances of operating systems to be run on a single system. This document is intended for hardware system manufacturers and software developers of applications, operating systems, or tools.

Virtualization Environment Overview

The term virtualization environment refers to the system environment created by the VMM to run virtualized software1. Figure 2-2 shows the main components in a virtualization environment2, and the interactions between them. A virtualization environment will include one or more processors supporting virtualization, the PAL supporting virtualization, the virtual machine monitor, and virtualized software. The VMM is required to allocate the resources and create the virtualization environment before guest software can be launched. In a virtualization environment, virtualized software will continue to execute on the processor unmodified. Interruptions from the processor will be handled by the VMM. A new architecture interface is defined between the VMM and PAL for access to configuration and optimization options, virtualization services, and virtualization intercept handling.

Resource Virtualization Policies

In a virtualization environment, guest operating systems are running virtualized. For each hardware and system resource on the system, there are typically two policies the VMM can choose to run the virtual processor(s) of the guest operating systems: