+ * This function is used to add another level to an IO page table. Adding
+ * another level increases the size of the address space by 9 bits to a size up
+ * to 64 bits.
+ */
+static bool increase_address_space(struct protection_domain *domain,
+ gfp_t gfp)
+{
+ u64 *pte;
+
+ if (domain->mode == PAGE_MODE_6_LEVEL)
+ /* address space already 64 bit large */
+ return false;
+
+ pte = (void *)get_zeroed_page(gfp);
+ if (!pte)
+ return false;
+
+ *pte = PM_LEVEL_PDE(domain->mode,
+ virt_to_phys(domain->pt_root));
+ domain->pt_root = pte;
+ domain->mode += 1;
+ domain->updated = true;
+
+ return true;
+}
+
+static u64 *alloc_pte(struct protection_domain *domain,
+ unsigned long address,
+ int end_lvl,
+ u64 **pte_page,
+ gfp_t gfp)
+{
+ u64 *pte, *page;
+ int level;
+
+ while (address > PM_LEVEL_SIZE(domain->mode))
+ increase_address_space(domain, gfp);
+
+ level = domain->mode - 1;
+ pte = &domain->pt_root[PM_LEVEL_INDEX(level, address)];
+
+ while (level > end_lvl) {
+ if (!IOMMU_PTE_PRESENT(*pte)) {
+ page = (u64 *)get_zeroed_page(gfp);
+ if (!page)
+ return NULL;
+ *pte = PM_LEVEL_PDE(level, virt_to_phys(page));
+ }
+
+ level -= 1;
+
+ pte = IOMMU_PTE_PAGE(*pte);
+
+ if (pte_page && level == end_lvl)
+ *pte_page = pte;
+
+ pte = &pte[PM_LEVEL_INDEX(level, address)];
+ }
+
+ return pte;
+}
+
+/*
+ * This function checks if there is a PTE for a given dma address. If
+ * there is one, it returns the pointer to it.
+ */
+static u64 *fetch_pte(struct protection_domain *domain,
+ unsigned long address, int map_size)
+{
+ int level;
+ u64 *pte;
+
+ level = domain->mode - 1;
+ pte = &domain->pt_root[PM_LEVEL_INDEX(level, address)];
+
+ while (level > map_size) {
+ if (!IOMMU_PTE_PRESENT(*pte))
+ return NULL;
+
+ level -= 1;
+
+ pte = IOMMU_PTE_PAGE(*pte);
+ pte = &pte[PM_LEVEL_INDEX(level, address)];
+
+ if ((PM_PTE_LEVEL(*pte) == 0) && level != map_size) {
+ pte = NULL;
+ break;
+ }
+ }
+
+ return pte;
+}
+
+/*