KVM is a Linux kernel module that turns the operating system into a hypervisor. Introduced in 2007, it allows a user-space program (like QEMU) to utilize the hardware virtualization features of modern processors (Intel VT-x or AMD-V). Unlike pure emulation, KVM allows the guest operating system to run instructions directly on the host CPU, drastically reducing overhead and increasing speed to near-bare-metal levels. The Synergy: How They Work Together In a typical setup, the two roles are clearly defined:
acts as the "brains" and "interface," providing the I/O device emulation (disk drives, network cards, USB controllers) and the management tools to start and stop the VMs. QEMU and Kernel-based Virtual Machine
When you run a command to start a KVM-accelerated VM, you are technically using QEMU to talk to the /dev/kvm interface. This collaboration allows for advanced features like , where a running VM is moved from one physical server to another without downtime. Conclusion KVM is a Linux kernel module that turns