MAKEPTE
pte = MAKEPTE(pfn, level);
newpte = MAKEPTE(pfn, 0) | mmu.pt_global | mmu.pt_nx;
pte = MAKEPTE(src->ht_pfn, 0) | mmu.pt_global | mmu.pt_nx;
newpte = MAKEPTE(dest->ht_pfn, 0) | PT_WRITABLE;