
Accesses to unassigned io ports shall return -1 on read and be ignored on write. Ensure these properties via dedicated ops, decoupling us from the memory core's handling of unassigned accesses. Cc: qemu-stable@nongnu.org Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>