Share via

Hyper-V: Troubleshoot BIOS Settings for HP Compaq dc7800

  • Article

There are three VT-related settings in the BIOS setup as follows:

  • Virtualization Technology (VTx) set to on/enable
  • Virtualization Technology Directed I/O (VTd) set to offf/disabled
  • Data Execution Prevention set to on/enable

 "Virtualization Technology Directed I/O" is support in the chipset for device assignment to a VM.  Hyper-V doesn’t support that.

NOTE:   The machine must be completely powered off (pull the AC cable to be sure) after you change these BIOS settings.

For example, VTx is a processor mode, that requires a cold boot of CPU. On normal reboot it does not power off.

NOTE: In some servers you even have to wait a minute before powering it on again. This is because of a security feature which ensures that that the virtualization setting can be written only once after power is applied to the processor.   Typically the BIOS consumes this one write during BIOS POST before you can get to the BIOS config.    On some machines that can take some time to drop power at the CPU.    

In general, when changing the BIOS settings to enable Hyper-V:

  1. Ensure you have the latest BIOS revision
  2. Change the setting in the BIOS.
  3. Save the BIOS settings. 
  4. Power off the machine with the power button.
  5. Pull the AC power cord and wait for a few minutes.