QEMU is a generic and open source machine emulator and virtualizer.

When used as a machine emulator, QEMU can run OSes and programs made for one
machine (e.g. an ARM board) on a different machine (e.g. your own PC). By using
dynamic translation, it achieves very good performance.

When used as a virtualizer, QEMU achieves near native performance by executing
the guest code directly on the host CPU. QEMU supports virtualization when
executing under the Xen hypervisor or using the KVM kernel module in Linux.
In NetBSD and DragonFly BSD, NVMM is employed to achieve hardware-accelerated
virtualization.

WWW: https://www.qemu.org/