When starting a configured virtual machine, an error occurs as follows:

# virsh start test
error: Failed to start domain test
error: Requested operation is not valid: PCI device 0000:03:10.1 is in use by domain rhel7

This error is often caused by a device that is already assigned to another guest or to the host itself.

Attempts to migrate and dump the virtual machine cause an error similar to the following:

# virsh dump rhel7/tmp/rhel7.dump

error: Failed to core dump domain rhel7 to /tmp/rhel7.dump
error: internal error: unable to execute QEMU command 'migrate': State blocked by non-migratable device '0000:00:03.0/vfio-pci'

Because device assignment uses hardware on the specific host where the virtual machine was started, guest migration and save are not supported when device assignment is in use. Currently, the same limitation also applies to core-dumping a guest; this may change in the future. It is important to note that QEMU does not currently support migrate, save, and dump operations on guest virtual machines with PCI devices attached, unless the --memory-only option is specified. Currently, it only can support these actions with USB devices. Work is currently being done to improve this in the future.