Virtual Machine Hardware-Intel's VT-X, VT-D, and VT-C technology Overview

"Choosing the right hardware platform for server virtualization is just as important as choosing the right virtualization software ." -IDC

Intel VT includes VT-X, VT-D, and VT-C technologies for processors, chipsets, and networks, respectively.

Processors: Intel virtualization technology (Intel VT-x), including Intel VT flexmigration, Intel VT flexpriority, and Intel VT extended page tables)

Chipset: Intel VT virtualization technology (Intel VT-d) that supports direct I/O access)

Network: supports connected intel virtualization technology (Intel VT-c), including virtual machine device Queue (vmdq) and Virtual Machine Direct Connection (vmdc)

Intel integrates hardware-assisted virtualization into all major server components to help it organizations integrate more applications and heavier workloads on each server, this further improves flexibility, reliability, and reduces TCO.

Processor: Intel VT-x

Intel's superior virtualization support for Intel VT-X in the Intel processor helps improve the flexibility and stability of software-based virtualization solutions. By eliminating the need for a virtual machine Monitor (vmm) to listen to, interrupt, and execute specific commands on behalf of the customer's operating system in accordance with the requirements of software virtualization, not only can the vmm intervention be effectively reduced, it also provides powerful hardware support for the control of the transmission platform between the vmm and the customer's operating system. In this way, vmm intervention is required to achieve fast, reliable, and secure switching.

In addition, the virtual machine Migration Feature of Intel VT-X provides strong protection for your IT investment and further enhances the flexibility of failover, load balancing, disaster recovery and maintenance:

-- Intel VT flexpriority: When a processor executes a task, it often receives requests or "interruptions" commands from other devices or applications that require attention. To minimize the impact on performance, a dedicated register (APIC task priority register, or TPR) in the processor monitors the task priority. In this way, only interruptions with a higher priority than the current running task will be promptly followed.

Intel flexpriority allows you to create a virtual copy of tpr6 that can be read and, in some cases, can be changed by the customer's operating system without intervention. These measures can significantly improve the performance of 32-bit TPR operating systems. (For example, it can improve the performance of applications running on Windows Server * 2000 by 35% .)

-- Intel virtualization flexible migration Technology (Intel VT flexmigration): an important advantage of virtualization is the ability to migrate running applications between physical servers without downtime. Intel VT flexmigration is designed to achieve seamless migration between current intel processor-based servers and future servers, even if new systems may include enhanced instruction sets. With this technology, the management program can establish a set of consistent commands on all servers in the migration pool to achieve seamless migration of workload. This generates a more flexible and unified server resource pool that can run seamlessly in multiple generations of hardware.

Chipset: Intel VT-d

The intel chipset provides better virtualization support because more customer operating systems are integrated on each server, the amount of data transferred (I/O traffic) to and from the system increases and becomes more complex. Without hardware assistance, the Virtual Machine monitor (vmm) must be directly involved in each I/O transaction. This not only slows down the data transmission speed, but also increases the server processor load due to more frequent vmm activities. This is like a busy shopping center where every customer has to go in and out through a door and can only receive instructions from the center manager. This will not only delay the customer's time, but also make the manager unable to handle other emergencies.

Intel VT-D not only accelerates data transmission, but also eliminates most of the performance overhead by reducing the need for vmm to manage I/O traffic. This is achieved by enabling vmm to securely allocate specific I/O devices to specific customers' operating systems. Each device has a dedicated area in the system memory. Only the device and its assigned customer operating system can access this area.

After initial allocation, the data can be transmitted directly between the customer's operating system and the devices allocated to it. In this way, the flow of I/O traffic will be faster, and the reduced vmm activity will further reduce the server processor load. In addition, the security and availability of the system are further enhanced because the I/o data used for specific devices or customers' operating systems cannot be accessed by any other hardware or customer software components.
 

Network: Intel VT-C

Better virtualization support in intel I/O equipment as enterprises deploy more and more applications in a virtualized environment, and use real-time migration to save power or improve availability, requirements for virtualized I/O devices are also significantly improved. By integrating a wide range of hardware auxiliary features into I/O devices (this device is used to maintain connections between servers and data center networks, storage infrastructure, and other external devices, intel VT-C further optimizes the network for virtualization. Essentially, the combination of these technologies features is very similar to the Post Office: Separate received letters, packages, and envelopes and deliver them to their respective destinations. By executing these functions on a dedicated network chip, Intel VT-C significantly improves delivery speed and reduces
Vmm and server processor load. Intel VT-C includes the following two key technologies (currently all Intel 10-Gigabit server NICs and selected intel Gigabit server NICs are supported ):

-- Maximize I/O throughput with virtual machine device Queue (vmdq): In traditional server virtualization environments, vmm must classify each individual packet, and send it to the Virtual Machine assigned to it. This will occupy a large number of processor cycles. With vmdq, this classification function can be performed by dedicated hardware in the Intel Server Nic. vmm only needs to send pre-classification data packet groups to appropriate customer operating systems. This reduces the I/O latency and enables the processor to have more available cycles to process business applications. Intel VT-C can increase I/O throughput by more than doubled, so that the throughput of virtualized applications is close to that of the local machine. Each server will integrate more applications, while there will be fewer I/O bottlenecks.

-- Dramatically improve virtualization performance with Virtual Machine Direct Connection (vmdc): With PCI-SIG single I/O Virtualization (SR-IOV) standard, Virtual Machine Direct Connection (vmdc) allows virtual machines to directly access network I/O hardware, significantly improving virtual performance. As mentioned above, Intel VT-D supports direct communication channels between the customer's operating system and the device's I/O Ports. The SR-IOV can scale this by supporting multiple direct communication channels per I/O port. For example, a single intel 10-Gigabit server Nic can allocate a protected, 1 GB/second dedicated link to each operating system in 10 customer operating systems. These direct communication links bypass vmm
Vswitch to further improve I/O performance and reduce server processor load.