KVM (kernel-based virtual machine)

KVM (kernel-based virtual machine)
Name	KVM (kernel-based virtual machine)
Developer	Linus Torvalds, Qumranet, Red Hat, IBM
Released	2007
Programming language	C (programming language)
Operating system	Linux kernel
License	GNU General Public License
Website	Linux Foundation

KVM (kernel-based virtual machine) is a virtualization subsystem integrated into the Linux kernel that transforms the kernel into a hypervisor by exposing processor virtualization extensions. It enables creation and management of multiple isolated execution environments, leveraging hardware features from vendors such as Intel Corporation and Advanced Micro Devices, while interfacing with userland tools from projects like QEMU and libvirt. KVM underpins virtualization deployments across enterprises, research institutions, and cloud providers including Amazon Web Services, Google Cloud Platform, and Microsoft Azure partners.

History

KVM originated at Qumranet in the mid-2000s and was merged into the Linux kernel mainline in 2007 under the stewardship of Linus Torvalds following development influenced by work at Xen (virtual machine monitor), VMware, Inc., and academic virtualization research from institutions such as University of Cambridge and Massachusetts Institute of Technology. Early contributions and commercial adoption involved Red Hat and later contributions by IBM, Intel Corporation, Advanced Micro Devices, and community developers associated with organizations like Canonical (company) and SUSE. The project evolved alongside standards from the Open Virtualization Alliance and integrations with orchestration projects such as OpenStack and container initiatives influenced by Docker, Inc. and Kubernetes.

Architecture

KVM is implemented as a pair of kernel modules that interface with processor features from Intel Corporation (VT-x) and Advanced Micro Devices (AMD-V), integrating with the Linux kernel scheduler, memory manager, and interrupt handling. The architecture delegates device emulation to userland processes such as QEMU while the in-kernel component provides virtualization primitives similar to traditional hypervisors like Xen (virtual machine monitor) and Hyper-V. Management and orchestration commonly use tools and APIs from libvirt, OpenStack, oVirt, and CloudStack. Networking and storage integration involve upstream projects and standards including Open vSwitch, NetworkManager, Ceph (software), and NVMe.

Features and Capabilities

KVM supports full virtualization on hardware with extensions from Intel Corporation and Advanced Micro Devices, live migration interoperable with cloud platforms like Amazon Web Services and Google Cloud Platform, and snapshotting used by orchestration systems such as oVirt and OpenStack. It supports device assignment technologies including VFIO and SR-IOV as specified by PCI-SIG, enabling direct passthrough for devices from vendors like NVIDIA and Broadcom. Storage and file formats commonly associated with KVM include QCOW2 and RAW, while performance and features benefit from paravirtualized drivers originating in projects such as VirtIO and collaborations with Red Hat and Intel Corporation.

Performance and Scalability

KVM leverages optimizations in the Linux kernel such as NUMA awareness, huge pages, and scheduler policies used by platforms like Red Hat Enterprise Linux and SUSE Linux Enterprise Server to scale across many cores in servers produced by manufacturers like Dell Technologies and Hewlett Packard Enterprise. Benchmarks from cloud providers and research labs compare KVM against hypervisors such as Xen (virtual machine monitor), VMware ESXi, and Microsoft Hyper-V using workloads typified by standards bodies like SPEC and projects from Phoronix Test Suite. Horizontal scaling is achieved with orchestration tools including Kubernetes and OpenStack, while vertical performance is enhanced through features supported by Intel Corporation and Advanced Micro Devices firmware teams.

Security and Isolation

KVM relies on hardware-assisted isolation from Intel Corporation and Advanced Micro Devices virtualization extensions and complements that with kernel-level mitigations developed within the Linux kernel community alongside security frameworks like SELinux and AppArmor. Isolation is hardened via techniques including IOMMU management from PCI-SIG and VFIO drivers developed collaboratively by contributors from Red Hat and Intel Corporation. Security incidents and mitigations have involved collaboration between vendors such as Google and organizations like the Open Web Application Security Project, with upstream fixes reviewed through Kernel.org workflows and community governance.

Use Cases and Implementations

KVM is used by public cloud providers including Amazon Web Services, Google Cloud Platform, and Alibaba Group partners, on-premises virtualization stacks from Red Hat (via Red Hat Virtualization), and in enterprise offerings from IBM and Canonical (company). Research and high-performance computing deployments at institutions like CERN and national laboratories leverage KVM for reproducible environments, while telecommunications vendors implementing 5G infrastructure use KVM alongside projects like OpenStack and Open Network Automation Platform. Edge computing and IoT gateways produced by vendors such as Intel Corporation and ARM Holdings often incorporate KVM-based virtualization for workload isolation.

Development and Community

Development occurs on repositories hosted by Kernel.org and coordination through mailing lists and code review systems used by the Linux kernel community, with major contributions from companies including Red Hat, IBM, Intel Corporation, and SUSE. The ecosystem includes related projects and standards bodies such as QEMU, libvirt, OpenStack, Linux Foundation, and the Open Virtualization Alliance that drive interoperability, testing, and certification efforts. Governance follows upstream kernel processes guided by maintainers and influential contributors like Linus Torvalds and specialized maintainers affiliated with organizations such as Red Hat and Canonical (company).

Category:Virtualization