VMM_IS_OPEN
if ((sc->vmm_flags & (VMM_HELD | VMM_IS_OPEN)) == 0) {
sc->vmm_flags |= VMM_IS_OPEN;
VERIFY3U(sc->vmm_flags & VMM_IS_OPEN, !=, 0);
sc->vmm_flags &= ~VMM_IS_OPEN;