From a HyperV Windows Guest you can find out what HyperV Host the Guest VM is running on. This post tells you how.
Option 1
Look at the following registry key, it will contain the Host Name of the HyperV Host.
HKLM\Software\Microsoft\Virtual Machine\Guest\Parameters\HostName
Option 2
Query the registry key using PowerShell.
(Get-Item "HKLM:\SOFTWARE\Microsoft\Virtual Machine\Guest\Parameters").GetValue("HostName")