title: Virtualbox enable nested vtx/amd-v greyed out
body: <p>On my <strong>Ubuntu 18.04</strong>, I've installed <strong>VirtualBox 6.0</strong> in order to have <strong><em>nested virtualization</em></strong>. Virtualization is <strong>enabled</strong> in my bios.</p>
  
  <p>However, when I open the settings of my (powered off) virtual machine and go to <strong>System</strong> -> <strong>Processor</strong>, the option "<strong>Enable Nested VT-x/AMD-V</strong>" is greyed out and I cannot enable it.</p>
  
  <p><a href="https://i.stack.imgur.com/RT2kA.png" rel="noreferrer"><img src="https://i.stack.imgur.com/RT2kA.png" alt="enter image description here"></a></p>