QEMU runs the guest code via the KVM kernel module. When working with KVM, QEMU also does I/O emulation, I/O device setup, live migration, and so on. QEMU opens the device file (/dev/kvm) exposed by the KVM kernel module and executes ioctls()on it
KVM exposesa device file called /dev/kvmto applications to make use of the ioctls()provided. QEMU makes use of this device file to talk with KVM and to create, initialize, and manage the kernel mode context of virtual machines