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Ensuring Virtualization Technology is enabled on your VMware host

Symptoms

  • Unable to power on a 64bit virtual machine.
  • The CPU is Virtual Technology-capable, but Virtualization Technology (VT) is not enabled.
  • Unable to install a 64bit operating system.
  • The following error is presented: The CPU of the host is incompatible with the CPU feature requirements of the virtual machine; problem detected at CPUID level 0x80000001 register 'edx' .
  • Virtual machine has been migrated and it no longer powers on.
  • The following error is presented when trying to VMotion to a host that does not have VT enabled: The CPU of the host is incompatible with the CPU feature requirements of virtual machine .

Purpose

Intel CPUs require EM64T and VT support in the chip and in the BIOS to run 64bit virtual machines. This article helps you ensure your processor is VT capable and it also instructs you on how to enable this feature.

Resolution

Ensure that your processor supports EM64T and VT.
 
All Intel Xeon processors feature:
  • Intel Virtualization Technology
  • Intel Extended Memory 64 Technology
  • Execute Disable Bit
You can check your processor's compatibility using the following link to the Intel Website:

Note: Intel Virtualization Technology (Intel VT), Intel Trusted Execution Technology (Intel TXT), and Intel 64 architecture require a computer system with a processor, chipset, BIOS, enabling software and/or operating system, device drivers and applications designed for these features. Performance varies depending on your configuration. Contact your vendor for more information.
 
Note: Intel EM64T requires a computer system with a processor, chipset, BIOS, operating system, device drivers and applications enabled for Intel EM64T. The processor does not operate (including 32bit operation) without an Intel EM64T-enabled BIOS. Performance varies depending on your hardware and software configurations. Intel EM64T-enabled operating systems, BIOS, device drivers, and applications may not be available. F or more information, including details on which processors support Intel EM64T, see www.intel.com/technology/architecture-silicon/intel64/  or consult with your system vendor for more information.
 
After you have confirmed your processor supports VT, you may need to enable the support:
  1. VT must be enabled in the host system BIOS. The feature may be named VT, Vanderpool Technology, Virtualization Technology, VMX, or Virtual Machine Extensions. Often, you find this setting under a Security screen in the BIOS. The location of this setting may change depending on the system vendor.

  2. The VT setting is locked (either on or off) at power on. After enabling VT in your system BIOS, you can first save your changes to the BIOS settings and then turn off power to the system. When you turn the system on again, your changes take effect. If you simply reboot the system without turning it off, VT is not enabled.

  3. After you have power cycled the system, confirm that your system is capable of running 64bit guests, by:

    • Booting from a CD containing the CPU Compatibility Tool included on the ESX Server 3.x CD-ROM in /images/cpuid.iso or by downloading it from www.vmware.com/download/shared_utilities.html.

    • Using the Workstation Processor Check for 64bit compatibility, which can be downloaded from http://www.vmware.com/download/ws/drivers_tools.html .

    • Some system vendors ship VT-capable systems without the ability to enable VT in the system BIOS.
      If you cannot find a way to enable VT in the system BIOS, contact your system vendor. An updated BIOS may be available.
    • Some laptops require a total power discharge to enable VT extensions once you have set it in the BIOS. To do this, disconnect the external power, and remove the battery from the laptop. Then, press the power button on the device to drain all power. Once this is done, replace the battery and reconnect the external power, and verify you are able to utilize the extensions.

All links valid as of 04 Mar 2008, please rate this article to report an issue with any of the links.

Additional Information

A sample output of the ESX CPU Compatibility Tool:
 
Reporting CPUID for 2 logical CPUs...

All CPUs are identical
Family: 0f Model: 04 Stepping: 1
ID1ECX ID1EDX ID81ECX ID81EDX
0x0000641d 0xbfebfbff 0000000000 0x20100000

Vendor : Intel
Processor Cores : 1
Brand String : " Intel(R) Xeon(TM) CPU 2.80GHz"
SSE Support : SSE1, SSE2, SSE3
Supports NX / XD : Yes
Supports CMPXCHG16B : Yes
Hyperthreading : Yes
Supports 64-bit Longmode : Yes
Supports 64-bit VMware : No

On Intel systems, the last line indicates "Yes" when the CPUs support EM64T and Intel Virtualization Technology (VT).

On AMD systems the last line indicates "Yes" on any 64bit enabled Opteron (Rev E or later).

Note: It has been reported that enabling Trusted Execution in the BIOS also causes of this issue.

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Actions
  • KB Article: 1003944
  • Updated: Nov 17, 2009
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