DBG_STACK_SIZE
static char dbg0_stack[DBG_STACK_SIZE] __aligned(16);
np = ((struct nmi_pcpu *)&dbg_stack[DBG_STACK_SIZE]) - 1;
DOMAINSET_PREF(domain), DBG_STACK_SIZE,
pmap_pti_add_kva_locked(va - DBG_STACK_SIZE, va, false);