IOMMU_PAGE_SHIFT
c.address = base >> IOMMU_PAGE_SHIFT;
x = IOMMU_PAGE_SHIFT + IOMMU_NPTEPGSHIFT * lvl;
run_sz = pg_sz >> IOMMU_PAGE_SHIFT;
isize = 1ULL << (am + IOMMU_PAGE_SHIFT);
base >>= IOMMU_PAGE_SHIFT + (pglvl - lvl - 1) *