Yes, you could apply this change in compiler output without functionality impact to existing userspace applications. But you&#x27;d have to recompile everything, and it&#x27;s not clear how it&#x27;d be <i>useful</i>; part of the question is what the privileged interfaces should be.<p>For Chrome this is useful because they want Chrome itself to be an unprivileged application, and they want to be essentially a recursive kernel to untrusted web content: there are multiple &quot;users&quot; (websites) that shouldn&#x27;t be able to access each other&#x27;s content, and certainly shouldn&#x27;t be able to mess with the browser itself, and they get a restricted filesystem-like thing, screen-like thing, etc.<p>For a general-purpose OS, the OS is assumed to have control of the CPU and can just use normal hardware protection. So it&#x27;s primarily useful if you want to build an OS that can be installed inside an unprivileged user account on another OS. But in practice, most people grant their unprivileged user account enough privilege to use hardware-assisted virtualization.