A recent development in the VirtualBox source tree introduces an early but usable KVM backend for Linux hosts. According to a comment by contributor Alexander Eichner, the new backend is now in a workable state, or at least when running modern guest operating systems. Older or more unusual guests, such as DOS, have not yet been tested.

And if you’re wondering what benefits this brings, the main one is that having a KVM backend allows VirtualBox to continue running virtual machines even when its own kernel modules (vboxdrv, vboxnetflt, vboxnetflt, vboxnetflt) cannot be loaded.

This is especially relevant on modern Linux systems, where Secure Boot, kernel hardening, or distribution-specific policies can block third-party kernel drivers. In such cases, VirtualBox will now automatically fall back to using KVM if it is available on the host system.