[Fixed] Expose Hardware-Assisted Virtualization to the Guest OS Greyed Out

Why this option is greyed out? The hardware virtualization option can improve virtualization performance, but some reasons can cause the option can be chosen, including BIOS/UEFI settings, CPU compatibility, and hypervisor conflict.

By @Amelia Last Updated October 29, 2024
 

ESXi 6.7 – PCIe passthrough and “Expose hardware assisted virtualization to guest OS”

Hi. I want to PCIe pass-through my GPU to the WS2016 guest machine. I understand that i need to disable "Expose hardware assisted virtualization to guest OS", but the option is enabled and grayed out. Why i cannot change it and how i can disable nested virtualization for this particular guest?

- Question from Reddit

Hardware-assisted virtualization allows the guest operating system to interact directly with the hardware as a way to improve virtual machine performance and security. It relies on features such as Intel VT-x or AMD-V to allow the operating system to run seamlessly on the host. However, sometimes there are issues where the HAV option is grayed out or unavailable in the operating system settings and when this issue occurs it can limit the performance of the virtual machine, so it needs to be addressed in time. The next part of the article will focus on how to resolve this issue.

How to Resolve the Expose Hardware-Assisted Virtualization to the Guest OS Greyed Out

If the option Expose Hardware-Assisted Virtualization to the Guest OS is grayed out in the virtualization software it may limit the operation of the virtual machine, here are the steps you can take to resolve the issue.

1. Verify CPU Virtualization Support

Ensure that your CPU supports hardware virtualization, for Intel processors, find out if Intel VT-x is supported, and for AMD processors, see if ADM-V is supported.

▶Using Windows to check: You need to open the Command Prompt and type systemifo, then look for Virtualization Enabled in Fireware.

▶Using Linux to check: You can use the following command

lscpu | grep Virtualization

2. Enable Virtualization in BIOS/UEFI

When you have ensured that your CPU supports virtualization, you need to ensure it is enabled in the BIOS/UEFI.

▶Restart your computer and press F2, f10, or Delete during startup to enter the BIOS/UEFI settings.

▶Navigate to the CPU or Advanced settings and look for virtualization options to enable the Intel Virtualization Technology.

▶Enable these options, then save and exit the BIOS.

3. Check Hypervisor Settings

If you are using Windows, check if Hyper-V or other hypervisors are enabled, and vice versa for the same reason, as they may conflict with other virtualization software.

▶Disable Hyper-V

In the Control Panel, go to Programs and Features and select Turn Windows features on or off. Then expand the Hyper-V, and uncheck Hyper-V and any related features.

▶Disable Windows Security Features

In the Windows Security, go to Device Security and select Core Isolation Details, then disable Memory Integrity.

Protect Your Virtualized Environments via AOMEI Cyber Backup

When hardware-assisted virtualization to the guest OS is greyed out, this means that the virtualized environment is not supported by hardware, resulting in limited security features. Also, running the guest OS without hardware support may cause it to crash or become unstable, thus putting data at risk of loss.

AOMEI Cyber Backup is a professional VMware backup tool that protects virtual machines from security threats. 

You can use AOMEI Cyber Backup to enjoy the following features:

✍Automated VM Backup: You can schedule VMware or Hyper-V virtual machine backups and perform hot backups to protect critical data with minimal manual intervention. ✍Instant Disaster Recovery: It can instantly restore an entire virtual machine to a previous state from any selected version of history. ✍Centralized Management: It provides a centralized interface for managing backup tasks across multiple VMware ESXi hosts. ✍Easy to Use: It offers a user-friendly interface, making backup processes hassle-free and accessible for everyone. ✍Role Assignment: It allows an administrator to create sub-accounts with limited privileges, effectively reducing administrative costs and manual errors.

Download FreewareVMware ESXi & Hyper-V
Secure Download

Automate Backup of Multiple VMs with AOMEI Cyber Backup

Step 1. Download AOMEI Cyber Backup, navigate to Source Device > VMware > + AddVMware Device to Add vCenter or Standalone ESXi. Then enter Device Information and User Information, after finishing, click Confirm.

Step 2. Navigate to Backup Task > Create New Task, and select VMware ESXi Backup as the Backup Type. Then set up Task Name, Device Name, Target, ArchiveSchedule, and Email Notification.

✦ Device Name: Select the host and virtual machines you want to back up.

✦ Target: Select a destination to store virtual machine files. It offers local or network location, also you can connect external hard drive to VM to store the backup files.

Archive: You can add an Amazon S3 storage and archive VMware Backup versions to this S3 storage.

✦ Schedule: It offers flexible backup strategies, such as full, incremental, and differential backup to safeguard VMware data comprehensively. You can specify the backup time as daily, weekly, or monthly which will offer continuous protection.

✦ Email Notification: Turn on the email notification, then it will send you emails to notify you the backup process and the abnormality.

Step 3. Click Start Backup, you can select Add the schedule only, or Add the schedule and start backup now.

Step 4. Click Restore, and choose the restore VMs. You can choose to Restore to original location, and click Start Restore.

FAQ about Virtualization

Q: Do I need to enable virtualization in BIOS for VMware?

A: Yes, once virtualization is enabled, you can create and run virtual machines in VMware without issues.

Q: Is enabling hardware virtualization safe?

A: Yes, enabling hardware virtualization is safe, and it’s a standard practice for running virtual machines.

Q: How many types does hardware virtualization have?

A: Three types, including full virtualization, paravirtualization, and hard-assisted virtualization.

Conclusion

When there are potential configuration issues or limitations, the expose hardware-assisted virtualization to the guest OS greyed out option may be grayed out and then unelectable. After going through the steps provided in this article to ensure that configuration and other issues are resolved, you will be able to maximize the high performance of virtualization and have a smoother virtualization experience.