LinuxKVM

LinuxKVM, commonly referred to as KVM on Linux, is a virtualization infrastructure integrated into the Linux kernel that enables a host system to run multiple isolated virtual machines. It consists of a pair of kernel modules, kvm.ko and a hardware-specific module such as kvm_intel.ko or kvm_amd.ko, and provides the /dev/kvm interface used by user-space virtualization tools. By leveraging hardware virtualization extensions (Intel VT-x or AMD-V), KVM allows guest operating systems to execute directly on the host CPU with near-native performance. The kernel handles CPU and memory virtualization, while user-space processes provide device emulation and I/O services.

KVM relies on user-space VM managers, with QEMU as the most common companion. Tools such as libvirt and virt-manager offer higher-level management interfaces. Guests can run unmodified Linux, Windows, or other operating systems. Performance is enhanced through paravirtualized drivers (for example, virtio) to optimize network and storage I/O. KVM supports features such as live migration of running virtual machines between hosts and various snapshot and storage options, typically coordinated through the user-space manager.

Hardware requirements include a processor with hardware virtualization extensions and a Linux kernel with KVM support enabled. Nested virtualization is possible on certain CPUs and kernel versions. Linux distributions commonly ship with KVM support ready to use, making it a popular choice for servers, cloud platforms, and desktop virtualization environments.

History and adoption: KVM was merged into the Linux kernel in 2007, led by Avi Kivity, and has since become a standard, widely deployed virtualization solution in many Linux-based infrastructures.