QEMU can emulate z/Architecture (in particular, 64 bit) s390x systems via the qemu-system-s390x binary. Only one machine type, s390-ccw-virtio, is supported (with versioning for compatibility handling).
When using KVM as accelerator, QEMU can emulate CPUs up to the generation of the host. When using the default cpu model with TCG as accelerator, QEMU will emulate a subset of z13 cpu features that should be enough to run distributions built for the z13.
QEMU will not emulate most of the traditional devices found under LPAR or z/VM; virtio devices (especially using virtio-ccw) make up the bulk of the available devices. Passthrough of host devices via vfio-pci, vfio-ccw, or vfio-ap is also available.
s390x/vfio-ap s390x/css s390x/3270 s390x/vfio-ccw
s390x/bootdevices s390x/protvirt