Overview of the Intel VT Virtualization Features
This article will explain the various components of Intel Virtualization Technology (Intel VT).
- 1 Intel VT-x (Intel Virtualization Technology for IA-32 and Intel 64 Processors)
- 2 Intel VT-i (Intel Virtualization Technology for Itanium Processors)
- 3 Intel VT-d (Intel Virtualization Technology for Directed I/O)
- 4 Intel VT-c (Intel Virtualization Technology for Connectivity)
- 5 Table of References
- 6 Additional Information
Intel VT-x (Intel Virtualization Technology for IA-32 and Intel 64 Processors)
Intel VT-x (previously known as Intel VT) is the implementation of an Intel Secure Virtual Machine for the x86 IA-32 and Intel 64 architectures. The older designation, “Intel VT” (without the “x”), continues to be used by many BIOS menus.
VT-x is necessary for Intel systems in order to:
- run domUs under Xen Hardware Virtual Machine (HVM) (as well as run a guest system under Windows).
- run 64-bit guest systems under VMware.
- to run virtualization with KVM.
Information regarding the activation of Intel VT-x at the BIOS level (if supported by the Intel processor) can be found in the article, Activating the Intel VT Virtualization Feature.
Intel VT-i (Intel Virtualization Technology for Itanium Processors)
Intel VT-d (Intel Virtualization Technology for Directed I/O)
Intel VT-d makes direct access to a PCI device possible for guest systems with the help of the Input/Output Memory Management Unit (IOMMU) provided. This allows a LAN card to be dedicated to a guest system, which makes attainment of increased network performance beyond that of an emulated LAN card possible. Of course, once such a direct access system has been implemented, live migration of the guest system is no longer possible. VMware can be configured for use with an activated Intel VT-d system using VMware VMDirectPath for direct access to PCI cards.
Pre-requisites for Intel VT-d
- The chip set as well as the BIOS used must support Intel VT-d.
- Requires the Intel Nehalem or later micro-architecture, such as that found in Xeon 34xx, 55xx and more recent, as well as other, desktop CPUs (see A List of Intel CPUs).
- There are no special requirements placed on the CPUs themselves, since VT-d is a function of the chip set. The CPU need merely support VT in general (see ).
Information regarding the activation of Intel VT-d at the BIOS level (if supported by the Intel processor) can be found in the article, Activating the Intel VT-d Virtualization Feature.
For additional information regarding VT-d, see:
- Understanding VT-d: Intel Virtualization Technology for Directed I/O (Intel Software Network)
- Step by Step Guide on How to Enable VT-d and Perform Direct Device Assignment (Intel Software Network)
- Intel Virtualization Technology for Directed I/O (VT-d): Enhancing Intel platforms for efficient virtualization of I/O devices (Intel Software Network)
- VTdHowTo (Xen Wiki)
- VMware VMDirectPath and Intel VT-d (YouTube)
- Intel Virtualization Technology for Directed I/O Architecture Specification (Intel Coporation)
Intel VT-c (Intel Virtualization Technology for Connectivity)
Intel VT-c is a collection of input/output (I/O) virtualization technologies. These technologies include:
- Intel I/O Acceleration Technology for the Reduction of CPU Loads
- Virtual Machine Device Queues (VMDq) for the reduction of system latency, including:
- Single Root I/O Virtualization (SR-IOV) for the improvement of network I/O throughput (also known as Virtual Machine Direct Connect (VMDc))
The article, Activating the SR-IOV Virtualization Feature contains additional information about activating SR-IOV.
For additional information regarding VT-c, see:
- Understanding VT-c: Virtualization Technology for Connectivity (Intel Software Network)
- PCI-SIG SR-IOV Primer
The following, as well as other, platforms support VT-c:
- Intel 75xx systems (Intel 7500 Chipset Boxboro-EX)
Table of References
- VMware Knowledge Base: Hardware and Firmware Requirements for 64-Bit Guest Operating Systems
- KVM FAQs:What do I need to use kvm?
- Technology Brief: Intel Nehalem Virtualization Technology Micro-architecture
- First the Tick, Now the Tock: Next Generation Intel Microarchitecture (Nehalem)
- VT-d Support on the Intel® Xeon® processor 5500/5600 Series (intel.com)
- Technology Brief: Intel Virtualization Technology for Connectivity
- Features Enabled by the Intel® 7500 Chipset Include: Supports Intel® VT for Connectivity: (Intel® VT-c) which reduces I/O latency. Intel Xeon Processor 7500 Series Product Brief (page 6)
- Intel Virtualization Technology (Intel VT)
- Intel Virtualization Technology: Hardware Support for Efficient Processor Virtualization (Intel Technology Journal)
- Intel Virtualization Technology for Directed I/O (Intel Technology Journal)
Author: Werner Fischer
Werner Fischer, working in the Web Operations & Knowledge Transfer team at Thomas-Krenn, completed his studies of Computer and Media Security at FH Hagenberg in Austria. He is a regular speaker at many conferences like LinuxTag, OSMC, OSDC, LinuxCon, and author for various IT magazines. In his spare time he enjoys playing the piano and training for a good result at the annual Linz marathon relay.