News

UPDATE: Hyper-V Needs SP1 for New Intel vPro Chips

• By Kurt Mackie
• 04/26/2011

Strictly speaking, Microsoft Windows Server 2008 R2 and Hyper-V Server 2008 R2 can't perform server virtualization using Intel's new second-generation Core vPro processors, formerly code-named "Sandy Bridge."

Virtual machines won't run due to a new feature in the chips, according to a Microsoft blog. An "advanced vector extension" (AVX) technology that's included in the new Intel Core vPro chips is the issue. Microsoft designed its server virtualization technology to not run "unknown processor capabilities" that could "potentially harm the guest OS," the blog explains. Microsoft's solutions were developed before Intel released the chips using AVX, so that's why the chips aren't supported.

The picture changes, however, if users apply Service Pack 1 (SP1), which Microsoft released in February for Windows Server 2008 R2. Earlier this month, Microsoft released SP1 for Hyper-V Server 2008 as well.

Various news accounts, such as this blog, have reported that applying SP1 to Windows 7 and Windows Server 2008 R2 will enable support for Intel's AVX technology in the new Intel Core vPro chips. Curiously, Microsoft's "release notes" and "notable changes" documentation for Windows Server 2008 R2 SP1 fail to mention this support.

Update: Microsoft, in an April 27 blog post, noted that there are some performance hotfixes for systems running Sandy Bridge and Westmere Intel Core vPro chips. These hotfixes might address the problem without requiring SP1, but it's not wholly clear.

Update 2: Microsoft offers a hotfix to Windows Server 2008 R2 that addresses the problem in which virtual machines won't start running on Sandy Bridge Intel Core vPro chips. However, an April 30 blog post by Microsoft clarifies that this hotfix restores AVX capability for the "parent partition," but not for the virtual machine on the guest operating system. Consequently, it seems that applying SP1 is Microsoft's generally recommended course of action.

The notion that SP1 adds support for Intel's new chips is also reflected in a brief entry at the end of Microsoft's support forum on the topic. "Downloaded an unofficial SP1 release of WS2008R2, and I could start them [virtual machines] straight after," the Feb. 6 entry states.

Intel's new Core vPro processors, which update its i3, i5 and i7 Core product line, were released to the market in March. Currently, the new vPro processors are aimed at the PC market, as well as notebooks. However, they are also designed to support servers.

Intel describes its AVX technology as "a new 256-bit instruction" designed to enhance virtual machine management and provide support for performance-intensive applications, such as video, audio, financial analytics or scientific simulations, according to an Intel publication (PDF). One difference with the second-generation processors is that all of the cores are integrated onto a single chip, which supposedly helps to boost processing power for visual-based applications. The new chips also include Intel's "hyper-threading technology," which purportedly doubles capacities by allowing "each processor core to work on two tasks at the same time," according to Intel.

Support for desktop virtualization using the new Core vPro chips is an ongoing process. An Intel publication, dated March 7 (PDF), states that "to ensure that the 2nd Generation Intel Core vPro processors can accommodate any desktop virtualization model, Intel is working with companies such as Citrix, Microsoft, MokaFive, RingCube, Virtual Computer, VMWare and Manova on a number of solutions and approaches."