QEMU is a virtualization tool and fast, dynamically translating, emulator. Used as a virtualization tool, it leverages KVM to execute instructions and either hardware virtualization or software emulation for peripherals. When virtualization is unavailable or the host and guest architectures don’t match, such as AArch64 running on x86_64, it can emulate either a full system or “user mode”, in which just user-level instructions are emulated and system calls are translated and serviced by the host operating system.