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Migration with VMotion between some Intel Xeon Pentium 4 processors causes some 64-bit versions of Windows to exit (1008749)

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Migration with VMotion between some Intel Xeon Pentium 4 processors causes some 64-bit versions of Windows to exit.
Three components interact to cause this problem:
  • The prefetchw opcode
Some Intel Xeon Pentium 4 processors produce a fault when executing AMD's prefetchw instruction (opcode 0x0F 0x0D). Because there is no CPUID feature bit to test to determine whether the opcode produces a fault on a Pentium 4 processor, software depending on the prefetchw instruction must use other methods to determine this. Applications on Intel systems might execute the instruction and check for faults or rely on the CPUID family and model information to determine the expected behavior.
  •  Kernel Patch Protection in 64-bit versions of Windows
The Kernel Patch Protection (also known as PatchGuard) feature in 64-bit versions of Windows (for example, Windows XP Professional x64, Windows Server 2003 x64 SP1, and Windows Vista x64) is intended to protect the kernel from modification by malicious software. If an operating system driver or an application attempts to modify the kernel, PatchGuard generates a bug check and shuts down the system.
  • VMotion across processors differing in prefetchw behavior
A component of the Windows kernel monitors the result of executing the prefetchw instruction. This component is believed to modify the kernel and remove ocurrences of prefetchw if the instruction produces a fault on the current processor. This kernel modification might also occur when a migration with VMotion is performed between processors that differ in their prefetchw execution behavior. In x64 versions of Windows, PatchGuard incorrectly detects this action as an intrusion by malicious software, generates a bug check, and shuts down the Windows guest operating system with STOP code 0x109.


Do not use VMotion to migrate x64 Windows virtual machines between Intel Xeon Pentium 4 processors differing in prefetchw execution behavior.
To prevent automated migration with VMotion between these processors (for example, in a DRS cluster or another environment in which an automated process initiates the migration):
  1. Edit the vpxd.cfg file using a text editor. By default, the vpxd.cfg file is located in the C:\Documents and Settings\All Users\Application Data\VMware\VMware VirtualCenter directory on the VirtualCenter Server system.
  2. In the section that applies to your hosts, versions, and guests, add the following mask pattern within the <cpuFeatureMask> element to disallow VMotion between these processors:

    An example is shown below. Added lines are marked with a *.

    * <intel>
    * <level-1>
    * <ecx>----:----:----:----:R---:----:----:----</ecx>
    * </level-1>
    * </intel>
  3. Restart the VMware VirtualCenter Server Service to enable the new mask.     
For more information on VMotion CPU compatibility requirements for Intel processors, see KB 1991.
For more information on overriding CPU compatibility restrictions, see KB 1993.
For more information on Kernel Patch Protection, see Kernel Patch Protection: Frequently Asked Questions.

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