Guest OS CPU Type Unchanged After vMotion to Different Host

Products

• VMware vSphere ESXi 8.0

Issue/Introduction

Symptom:

After performing a VM vMotion operation, the CPU type reported by the Guest OS remains unchanged, for example,

• Initially VM is up and running on Host A with an Intel(R) Xeon(R) Silver 4216 CPU.
  • When checked via Windows Guest OS (Control Panel--->System--->About), the CPU is correctly identified as Intel(R) Xeon(R) Silver 4216.
• The VM is then migrated via vMotion to Host B, which has a different CPU(Intel(R) Xeon(R) Silver 4316)
  • Despite the migration, the Guest OS still report the CPU as Intel(R) Xeon(R) Silver 4216, instead of reflecting the new host's CPU.

Environment

VMware vSphere ESXi 8.0

Cause

The CPU instruction set available to the operating system and to applications running in a virtual machine is determined at the time that a virtual machine is powered on. While a virtual machine is powered-on, the set of features available to the virtual machine remains constant regardless of what host CPU the virtual machine runs on.

Resolution

After powering off the VM and powering on it on destination host, then Guest OS will correctly display the new host's CPU.

Additional Information

Please see below:

https://techdocs.broadcom.com/us/en/vmware-cis/vsphere/vsphere/8-0/vcenter-and-host-management-8-0/migrating-virtual-machines-host-management/cpu-compatibility-and-evc-host-management.html