PG_UWE
if (*pv->pv_pte & (PG_KWE | PG_UWE)) {
*pv->pv_pte &= ~(PG_KWE | PG_UWE);
up[prot] |= PG_KWE | PG_UWE;
if (!(*pte & (user ? PG_UWE : PG_UWE | PG_KWE))) {