Kernel-based Virtual Machine

Kernel-based Virtual Machine aka KVM

KVM (Kernel-based Virtual Machine) is an open source virtualization technology for Linux. It installs natively on all Linux distributions and turns underlying physical servers into hypervisors so that they can host multiple, isolated virtual machines (VMs). Kernel Virtual Machine consists of a loadable kernel module, kvm.ko, that provides the core virtualization infrastructure and a processor specific module, kvm-intel.ko or kvm-amd.ko.

KVM requires a processor with hardware virtualization extensions, such as Intel VT or AMD-V. KVM supports hardware-assisted virtualization for a wide variety of guest operating systems including BSD, Solaris, Windows, Haiku, ReactOS, Plan 9, AROS, macOS, and more.

On a linux system you can check to see if KVM support is enabled with the cpu-checker utility

sudo apt install cpu-checker
kvm-ok

The kvm-ok command will return something like the following if virtualization is enabled.

$ kvm-ok
INFO: /dev/kvm exists
KVM acceleration can be used

Software such as virtualbox requires virtualization enabled for purposes.

KVM is currently part of Linux since kernel 2.6.20. It was announced in 2006 and subsequently merged into the mainline Linux kernel version by 2007.

Using KVM, one can run multiple virtual machines running unmodified Linux or Windows images. Each virtual machine has private virtualized hardware: a network card, disk, graphics adapter and so on.