+typedef int (*vtd_page_walk_hook)(IOMMUTLBEntry *entry, void *private);
+
+/**
+ * vtd_page_walk_level - walk over specific level for IOVA range
+ *
+ * @addr: base GPA addr to start the walk
+ * @start: IOVA range start address
+ * @end: IOVA range end address (start <= addr < end)
+ * @hook_fn: hook func to be called when detected page
+ * @private: private data to be passed into hook func
+ * @read: whether parent level has read permission
+ * @write: whether parent level has write permission
+ * @notify_unmap: whether we should notify invalid entries
+ */
+static int vtd_page_walk_level(dma_addr_t addr, uint64_t start,
+ uint64_t end, vtd_page_walk_hook hook_fn,
+ void *private, uint32_t level,
+ bool read, bool write, bool notify_unmap)
+{
+ bool read_cur, write_cur, entry_valid;
+ uint32_t offset;
+ uint64_t slpte;
+ uint64_t subpage_size, subpage_mask;
+ IOMMUTLBEntry entry;
+ uint64_t iova = start;
+ uint64_t iova_next;
+ int ret = 0;
+
+ trace_vtd_page_walk_level(addr, level, start, end);
+
+ subpage_size = 1ULL << vtd_slpt_level_shift(level);
+ subpage_mask = vtd_slpt_level_page_mask(level);
+
+ while (iova < end) {
+ iova_next = (iova & subpage_mask) + subpage_size;
+
+ offset = vtd_iova_level_offset(iova, level);
+ slpte = vtd_get_slpte(addr, offset);
+
+ if (slpte == (uint64_t)-1) {
+ trace_vtd_page_walk_skip_read(iova, iova_next);
+ goto next;
+ }
+
+ if (vtd_slpte_nonzero_rsvd(slpte, level)) {
+ trace_vtd_page_walk_skip_reserve(iova, iova_next);
+ goto next;
+ }
+
+ /* Permissions are stacked with parents' */
+ read_cur = read && (slpte & VTD_SL_R);
+ write_cur = write && (slpte & VTD_SL_W);
+
+ /*
+ * As long as we have either read/write permission, this is a
+ * valid entry. The rule works for both page entries and page
+ * table entries.
+ */
+ entry_valid = read_cur | write_cur;
+
+ if (vtd_is_last_slpte(slpte, level)) {
+ entry.target_as = &address_space_memory;
+ entry.iova = iova & subpage_mask;
+ /* NOTE: this is only meaningful if entry_valid == true */
+ entry.translated_addr = vtd_get_slpte_addr(slpte);
+ entry.addr_mask = ~subpage_mask;
+ entry.perm = IOMMU_ACCESS_FLAG(read_cur, write_cur);
+ if (!entry_valid && !notify_unmap) {
+ trace_vtd_page_walk_skip_perm(iova, iova_next);
+ goto next;
+ }
+ trace_vtd_page_walk_one(level, entry.iova, entry.translated_addr,
+ entry.addr_mask, entry.perm);
+ if (hook_fn) {
+ ret = hook_fn(&entry, private);
+ if (ret < 0) {
+ return ret;
+ }
+ }
+ } else {
+ if (!entry_valid) {
+ trace_vtd_page_walk_skip_perm(iova, iova_next);
+ goto next;
+ }
+ ret = vtd_page_walk_level(vtd_get_slpte_addr(slpte), iova,
+ MIN(iova_next, end), hook_fn, private,
+ level - 1, read_cur, write_cur,
+ notify_unmap);
+ if (ret < 0) {
+ return ret;
+ }
+ }
+
+next:
+ iova = iova_next;
+ }
+
+ return 0;
+}
+
+/**
+ * vtd_page_walk - walk specific IOVA range, and call the hook
+ *
+ * @ce: context entry to walk upon
+ * @start: IOVA address to start the walk
+ * @end: IOVA range end address (start <= addr < end)
+ * @hook_fn: the hook that to be called for each detected area
+ * @private: private data for the hook function
+ */
+static int vtd_page_walk(VTDContextEntry *ce, uint64_t start, uint64_t end,
+ vtd_page_walk_hook hook_fn, void *private,
+ bool notify_unmap)
+{
+ dma_addr_t addr = vtd_ce_get_slpt_base(ce);
+ uint32_t level = vtd_ce_get_level(ce);
+
+ if (!vtd_iova_range_check(start, ce)) {
+ return -VTD_FR_ADDR_BEYOND_MGAW;
+ }
+
+ if (!vtd_iova_range_check(end, ce)) {
+ /* Fix end so that it reaches the maximum */
+ end = vtd_iova_limit(ce);
+ }
+
+ return vtd_page_walk_level(addr, start, end, hook_fn, private,
+ level, true, true, notify_unmap);
+}
+