[RFC,v2,6/6] powerpc/iommu: Implement the iommu_table_group_ops for pSeries

diff --git a/arch/powerpc/include/asm/iommu.h b/arch/powerpc/include/asm/iommu.h
index 784809e34abe..1e0c2b2882c2 100644
--- a/arch/powerpc/include/asm/iommu.h
+++ b/arch/powerpc/include/asm/iommu.h
@@ -181,9 +181,9 @@  struct iommu_table_group_ops {
 	long (*unset_window)(struct iommu_table_group *table_group,
 			int num);
 	/* Switch ownership from platform code to external user (e.g. VFIO) */
-	long (*take_ownership)(struct iommu_table_group *table_group);
+	long (*take_ownership)(struct iommu_table_group *table_group, struct device *dev);
 	/* Switch ownership from external user (e.g. VFIO) back to core */
-	void (*release_ownership)(struct iommu_table_group *table_group);
+	void (*release_ownership)(struct iommu_table_group *table_group, struct device *dev);
 };
 
 struct iommu_table_group_link {
diff --git a/arch/powerpc/kernel/iommu.c b/arch/powerpc/kernel/iommu.c
index 31dc663be0cc..2ad1e320f69f 100644
--- a/arch/powerpc/kernel/iommu.c
+++ b/arch/powerpc/kernel/iommu.c
@@ -1170,7 +1170,7 @@  spapr_tce_platform_iommu_attach_dev(struct iommu_domain *platform_domain,
 	 * The domain being set to PLATFORM from earlier
 	 * BLOCKED. The table_group ownership has to be released.
 	 */
-	table_group->ops->release_ownership(table_group);
+	table_group->ops->release_ownership(table_group, dev);
 	iommu_group_put(grp);
 
 	return 0;
@@ -1198,7 +1198,7 @@  spapr_tce_blocked_iommu_attach_dev(struct iommu_domain *platform_domain,
 	 * also sets the dma_api ops
 	 */
 	table_group = iommu_group_get_iommudata(grp);
-	ret = table_group->ops->take_ownership(table_group);
+	ret = table_group->ops->take_ownership(table_group, dev);
 	iommu_group_put(grp);
 
 	return ret;
diff --git a/arch/powerpc/platforms/powernv/pci-ioda.c b/arch/powerpc/platforms/powernv/pci-ioda.c
index 23f5b5093ec1..b0a14e48175c 100644
--- a/arch/powerpc/platforms/powernv/pci-ioda.c
+++ b/arch/powerpc/platforms/powernv/pci-ioda.c
@@ -1537,7 +1537,8 @@  static void pnv_ioda_setup_bus_dma(struct pnv_ioda_pe *pe, struct pci_bus *bus)
 	}
 }
 
-static long pnv_ioda2_take_ownership(struct iommu_table_group *table_group)
+static long pnv_ioda2_take_ownership(struct iommu_table_group *table_group,
+				     struct device *dev __maybe_unused)
 {
 	struct pnv_ioda_pe *pe = container_of(table_group, struct pnv_ioda_pe,
 						table_group);
@@ -1562,7 +1563,8 @@  static long pnv_ioda2_take_ownership(struct iommu_table_group *table_group)
 	return 0;
 }
 
-static void pnv_ioda2_release_ownership(struct iommu_table_group *table_group)
+static void pnv_ioda2_release_ownership(struct iommu_table_group *table_group,
+					struct device *dev __maybe_unused)
 {
 	struct pnv_ioda_pe *pe = container_of(table_group, struct pnv_ioda_pe,
 						table_group);
diff --git a/arch/powerpc/platforms/pseries/iommu.c b/arch/powerpc/platforms/pseries/iommu.c
index e701255560a6..470a86117b03 100644
--- a/arch/powerpc/platforms/pseries/iommu.c
+++ b/arch/powerpc/platforms/pseries/iommu.c
@@ -23,6 +23,8 @@ 
 #include <linux/memory.h>
 #include <linux/of.h>
 #include <linux/of_address.h>
+#include <linux/of_fdt.h>
+#include <linux/libfdt.h>
 #include <linux/iommu.h>
 #include <linux/rculist.h>
 #include <asm/io.h>
@@ -54,57 +56,6 @@  enum {
 	DDW_EXT_QUERY_OUT_SIZE = 2
 };
 
-static int iommu_take_ownership(struct iommu_table *tbl)
-{
-	unsigned long flags, i, sz = (tbl->it_size + 7) >> 3;
-	int ret = 0;
-
-	/*
-	 * VFIO does not control TCE entries allocation and the guest
-	 * can write new TCEs on top of existing ones so iommu_tce_build()
-	 * must be able to release old pages. This functionality
-	 * requires exchange() callback defined so if it is not
-	 * implemented, we disallow taking ownership over the table.
-	 */
-	if (!tbl->it_ops->xchg_no_kill)
-		return -EINVAL;
-
-	spin_lock_irqsave(&tbl->large_pool.lock, flags);
-	for (i = 0; i < tbl->nr_pools; i++)
-		spin_lock_nest_lock(&tbl->pools[i].lock, &tbl->large_pool.lock);
-
-	if (iommu_table_in_use(tbl)) {
-		pr_err("iommu_tce: it_map is not empty");
-		ret = -EBUSY;
-	} else {
-		memset(tbl->it_map, 0xff, sz);
-	}
-
-	for (i = 0; i < tbl->nr_pools; i++)
-		spin_unlock(&tbl->pools[i].lock);
-	spin_unlock_irqrestore(&tbl->large_pool.lock, flags);
-
-	return ret;
-}
-
-static void iommu_release_ownership(struct iommu_table *tbl)
-{
-	unsigned long flags, i, sz = (tbl->it_size + 7) >> 3;
-
-	spin_lock_irqsave(&tbl->large_pool.lock, flags);
-	for (i = 0; i < tbl->nr_pools; i++)
-		spin_lock_nest_lock(&tbl->pools[i].lock, &tbl->large_pool.lock);
-
-	memset(tbl->it_map, 0, sz);
-
-	iommu_table_reserve_pages(tbl, tbl->it_reserved_start,
-			tbl->it_reserved_end);
-
-	for (i = 0; i < tbl->nr_pools; i++)
-		spin_unlock(&tbl->pools[i].lock);
-	spin_unlock_irqrestore(&tbl->large_pool.lock, flags);
-}
-
 static struct iommu_table *iommu_pseries_alloc_table(int node)
 {
 	struct iommu_table *tbl;
@@ -196,7 +147,7 @@  static int tce_build_pSeries(struct iommu_table *tbl, long index,
 }
 
 
-static void tce_free_pSeries(struct iommu_table *tbl, long index, long npages)
+static void tce_clear_pSeries(struct iommu_table *tbl, long index, long npages)
 {
 	__be64 *tcep;
 
@@ -215,6 +166,37 @@  static unsigned long tce_get_pseries(struct iommu_table *tbl, long index)
 	return be64_to_cpu(*tcep);
 }
 
+static long pseries_tce_iommu_userspace_view_alloc(struct iommu_table *tbl)
+{
+	unsigned long cb = ALIGN(sizeof(tbl->it_userspace[0]) * tbl->it_size, PAGE_SIZE);
+	unsigned long *uas;
+
+	if (tbl->it_indirect_levels) /* Impossible */
+		return -EPERM;
+
+	WARN_ON(tbl->it_userspace);
+
+	uas = vzalloc(cb);
+	if (!uas)
+		return -ENOMEM;
+
+	tbl->it_userspace = (__be64 *) uas;
+
+	return 0;
+}
+
+static void tce_iommu_userspace_view_free(struct iommu_table *tbl)
+{
+	vfree(tbl->it_userspace);
+	tbl->it_userspace = NULL;
+}
+
+static void tce_free_pSeries(struct iommu_table *tbl)
+{
+	if (!tbl->it_userspace)
+		tce_iommu_userspace_view_free(tbl);
+}
+
 static void tce_free_pSeriesLP(unsigned long liobn, long, long, long);
 static void tce_freemulti_pSeriesLP(struct iommu_table*, long, long);
 
@@ -629,7 +611,7 @@  struct iommu_table_ops iommu_table_lpar_multi_ops;
 
 struct iommu_table_ops iommu_table_pseries_ops = {
 	.set = tce_build_pSeries,
-	.clear = tce_free_pSeries,
+	.clear = tce_clear_pSeries,
 	.get = tce_get_pseries
 };
 
@@ -738,17 +720,45 @@  static int tce_exchange_pseries(struct iommu_table *tbl, long index, unsigned
 
 	return rc;
 }
+
+static __be64 *tce_useraddr_pSeriesLP(struct iommu_table *tbl, long index,
+				      bool __always_unused alloc)
+{
+	return tbl->it_userspace ? &tbl->it_userspace[index - tbl->it_offset] : NULL;
+}
 #endif
 
 struct iommu_table_ops iommu_table_lpar_multi_ops = {
 	.set = tce_buildmulti_pSeriesLP,
 #ifdef CONFIG_IOMMU_API
 	.xchg_no_kill = tce_exchange_pseries,
+	.useraddrptr = tce_useraddr_pSeriesLP,
 #endif
 	.clear = tce_freemulti_pSeriesLP,
-	.get = tce_get_pSeriesLP
+	.get = tce_get_pSeriesLP,
+	.free = tce_free_pSeries
 };
 
+/*
+ * When the DMA window properties might have been removed,
+ * the parent node has the table_group setup on it.
+ */
+static struct device_node *pci_dma_find_parent_node(struct pci_dev *dev,
+					       struct iommu_table_group *table_group)
+{
+	struct device_node *dn = pci_device_to_OF_node(dev);
+	struct pci_dn *rpdn;
+
+	for (; dn && PCI_DN(dn); dn = dn->parent) {
+		rpdn = PCI_DN(dn);
+
+		if (table_group == rpdn->table_group)
+			return dn;
+	}
+
+	return NULL;
+}
+
 /*
  * Find nearest ibm,dma-window (default DMA window) or direct DMA window or
  * dynamic 64bit DMA window, walking up the device tree.
@@ -955,7 +965,7 @@  static void __remove_dma_window(struct device_node *np, u32 *ddw_avail, u64 liob
 }
 
 static void remove_dma_window(struct device_node *np, u32 *ddw_avail,
-			      struct property *win)
+			      struct property *win, bool cleanup)
 {
 	struct dynamic_dma_window_prop *dwp;
 	u64 liobn;
@@ -963,11 +973,13 @@  static void remove_dma_window(struct device_node *np, u32 *ddw_avail,
 	dwp = win->value;
 	liobn = (u64)be32_to_cpu(dwp->liobn);
 
-	clean_dma_window(np, dwp);
+	if (cleanup)
+		clean_dma_window(np, dwp);
 	__remove_dma_window(np, ddw_avail, liobn);
 }
 
-static int remove_ddw(struct device_node *np, bool remove_prop, const char *win_name)
+static int remove_dma_window_named(struct device_node *np, bool remove_prop, const char *win_name,
+				   bool cleanup)
 {
 	struct property *win;
 	u32 ddw_avail[DDW_APPLICABLE_SIZE];
@@ -982,9 +994,8 @@  static int remove_ddw(struct device_node *np, bool remove_prop, const char *win_
 	if (ret)
 		return 0;
 
-
 	if (win->length >= sizeof(struct dynamic_dma_window_prop))
-		remove_dma_window(np, ddw_avail, win);
+		remove_dma_window(np, ddw_avail, win, cleanup);
 
 	if (!remove_prop)
 		return 0;
@@ -1046,7 +1057,7 @@  static void find_existing_ddw_windows_named(const char *name)
 	for_each_node_with_property(pdn, name) {
 		dma64 = of_get_property(pdn, name, &len);
 		if (!dma64 || len < sizeof(*dma64)) {
-			remove_ddw(pdn, true, name);
+			remove_dma_window_named(pdn, true, name, true);
 			continue;
 		}
 
@@ -1423,7 +1434,7 @@  static bool enable_ddw(struct pci_dev *dev, struct device_node *pdn)
 		if (reset_win_ext)
 			goto out_failed;
 
-		remove_dma_window(pdn, ddw_avail, default_win);
+		remove_dma_window(pdn, ddw_avail, default_win, true);
 		default_win_removed = true;
 
 		/* Query again, to check if the window is available */
@@ -1768,24 +1779,380 @@  static unsigned long spapr_tce_get_table_size(__u32 page_shift,
 	return size;
 }
 
+/*
+ * The default window property always exists on the FDT, only during the kexec/kdump
+ * load its removed to match the DT actuals. So, its safe to fetch from FDT.
+ */
+static struct property *default_window_property_create(struct device_node *pdn)
+{
+	const void *fdt = initial_boot_params;
+	int fdt_root_offset, node_offset;
+	struct property *win;
+	const void *fdtprop;
+	int length;
+
+	fdt_root_offset = fdt_path_offset(fdt, "/");
+	node_offset = fdt_subnode_offset(fdt, fdt_root_offset, of_node_full_name(pdn));
+	if (node_offset < 0) {
+		pr_err("Failed to get the node %pOF from fdt\n", pdn);
+		return NULL;
+	}
+
+	fdtprop = fdt_getprop(fdt, node_offset, "ibm,dma-window", &length);
+	if (!length) {
+		pr_err("%pOF: Failed to get the ibm,dma-window property\n", pdn);
+		return NULL;
+	}
+
+	win = kzalloc(sizeof(struct property), GFP_KERNEL);
+	if (!win)
+		return NULL;
+
+	win->name = kstrdup("ibm,dma-window", GFP_KERNEL);
+	win->length = length;
+	win->value = kmemdup(fdtprop, length, GFP_KERNEL);
+	if (!win->value) {
+		kfree(win);
+		return NULL;
+	}
+
+	return win;
+}
+
+static struct pci_dev *iommu_group_get_first_pci_dev(struct iommu_group *group)
+{
+	struct pci_dev *pdev = NULL;
+	int ret;
+
+	/* No IOMMU group ? */
+	if (!group)
+		return NULL;
+
+	ret = iommu_group_for_each_dev(group, &pdev, dev_has_iommu_table);
+	if (!ret || !pdev)
+		return NULL;
+	return pdev;
+}
+
+static void restore_default_dma_window(struct pci_dev *pdev, struct device_node *pdn)
+{
+	struct property *def_win;
+	int ret;
+
+	reset_dma_window(pdev, pdn);
+
+	/* Restore the DT property from the FDT */
+	def_win = default_window_property_create(pdn);
+	if (!def_win)
+		return;
+	ret = of_add_property(pdn, def_win);
+	if (ret)
+		dev_err(&pdev->dev, "unable to add DMA window property for %pOF: %d",
+			pdn, ret);
+}
+
+static long remove_dynamic_dma_windows(struct pci_dev *pdev, struct device_node *pdn)
+{
+	struct pci_dn *pci = PCI_DN(pdn);
+	struct dma_win *window;
+	bool direct_mapping;
+	int len;
+
+	if (find_existing_ddw(pdn, &pdev->dev.archdata.dma_offset, &len, &direct_mapping)) {
+		remove_dma_window_named(pdn, true, direct_mapping ?
+						   DIRECT64_PROPNAME : DMA64_PROPNAME, true);
+		if (!direct_mapping) {
+			WARN_ON(!pci->table_group->tables[0] && !pci->table_group->tables[1]);
+
+			if (pci->table_group->tables[1]) {
+				iommu_tce_table_put(pci->table_group->tables[1]);
+				pci->table_group->tables[1] = NULL;
+			} else if (pci->table_group->tables[0]) {
+				/* Default window was removed and only the DDW exists */
+				iommu_tce_table_put(pci->table_group->tables[0]);
+				pci->table_group->tables[0] = NULL;
+			}
+		}
+		spin_lock(&dma_win_list_lock);
+		list_for_each_entry(window, &dma_win_list, list) {
+			if (window->device == pdn) {
+				list_del(&window->list);
+				kfree(window);
+				break;
+			}
+		}
+		spin_unlock(&dma_win_list_lock);
+	}
+
+	return 0;
+}
+
+static long pseries_setup_default_iommu_config(struct iommu_table_group *table_group,
+					       struct device *dev)
+{
+	struct pci_dev *pdev = to_pci_dev(dev);
+	const __be32 *default_prop;
+	long liobn, offset, size;
+	struct device_node *pdn;
+	struct iommu_table *tbl;
+	struct pci_dn *pci;
+
+	pdn = pci_dma_find_parent_node(pdev, table_group);
+	if (!pdn || !PCI_DN(pdn)) {
+		dev_warn(&pdev->dev, "No table_group configured for the node %pOF\n", pdn);
+		return -1;
+	}
+	pci = PCI_DN(pdn);
+
+	/* The default window is restored if not present already on removal of DDW.
+	 * However, if used by VFIO SPAPR sub driver, the user's order of removal of
+	 * windows might have been different to not leading to auto restoration,
+	 * suppose the DDW was removed first followed by the default one.
+	 * So, restore the default window with reset-pe-dma call explicitly.
+	 */
+	restore_default_dma_window(pdev, pdn);
+
+	default_prop = of_get_property(pdn, "ibm,dma-window", NULL);
+	of_parse_dma_window(pdn, default_prop, &liobn, &offset, &size);
+	tbl = iommu_pseries_alloc_table(pci->phb->node);
+	if (!tbl) {
+		dev_err(&pdev->dev, "couldn't create new IOMMU table\n");
+		return -1;
+	}
+
+	iommu_table_setparms_common(tbl, pci->phb->bus->number, liobn, offset,
+				    size, IOMMU_PAGE_SHIFT_4K, NULL,
+				    &iommu_table_lpar_multi_ops);
+	iommu_init_table(tbl, pci->phb->node, 0, 0);
+
+	pci->table_group->tables[0] = tbl;
+	set_iommu_table_base(&pdev->dev, tbl);
+
+	return 0;
+}
+
+static bool is_default_window_request(struct iommu_table_group *table_group, __u32 page_shift,
+				      __u64 window_size)
+{
+	if ((window_size <= table_group->tce32_size) &&
+	    (page_shift == IOMMU_PAGE_SHIFT_4K))
+		return true;
+
+	return false;
+}
+
 static long spapr_tce_create_table(struct iommu_table_group *table_group, int num,
 				   __u32 page_shift, __u64 window_size, __u32 levels,
 				   struct iommu_table **ptbl)
 {
-	struct iommu_table *tbl = table_group->tables[0];
-
-	if (num > 0)
-		return -EPERM;
+	struct pci_dev *pdev = iommu_group_get_first_pci_dev(table_group->group);
+	u32 ddw_avail[DDW_APPLICABLE_SIZE];
+	struct ddw_create_response create;
+	unsigned long liobn, offset, size;
+	unsigned long start = 0, end = 0;
+	struct ddw_query_response query;
+	const __be32 *default_prop;
+	struct failed_ddw_pdn *fpdn;
+	unsigned int entries_shift;
+	unsigned int window_shift;
+	struct device_node *pdn;
+	struct iommu_table *tbl;
+	struct dma_win *window;
+	struct property *win64;
+	struct pci_dn *pci;
+	u64 win_addr;
+	int len, i;
+	long ret;
 
-	if (tbl->it_page_shift != page_shift ||
-	    tbl->it_size != (window_size >> page_shift) ||
-	    tbl->it_indirect_levels != levels - 1)
+	if (!is_power_of_2(window_size) || levels > 1)
 		return -EINVAL;
 
+	window_shift = order_base_2(window_size);
+	entries_shift = window_shift - page_shift;
+
+	mutex_lock(&dma_win_init_mutex);
+
+	ret = -ENODEV;
+
+	pdn = pci_dma_find_parent_node(pdev, table_group);
+	if (!pdn || !PCI_DN(pdn)) { /* Niether of 32s|64-bit exist! */
+		dev_warn(&pdev->dev, "No dma-windows exist for the node %pOF\n", pdn);
+		goto out_failed;
+	}
+	pci = PCI_DN(pdn);
+
+	/* If the enable DDW failed for the pdn, dont retry! */
+	list_for_each_entry(fpdn, &failed_ddw_pdn_list, list) {
+		if (fpdn->pdn == pdn) {
+			dev_info(&pdev->dev, "%pOF in failed DDW device list\n", pdn);
+			goto out_unlock;
+		}
+	}
+
+	tbl = iommu_pseries_alloc_table(pci->phb->node);
+	if (!tbl) {
+		dev_dbg(&pdev->dev, "couldn't create new IOMMU table\n");
+		goto out_unlock;
+	}
+
+	if (num == 0) {
+		bool direct_mapping;
+		/* The request is not for default window? Ensure there is no DDW window already */
+		if (!is_default_window_request(table_group, page_shift, window_size)) {
+			if (find_existing_ddw(pdn, &pdev->dev.archdata.dma_offset, &len,
+					      &direct_mapping)) {
+				dev_warn(&pdev->dev, "%pOF: 64-bit window already present.", pdn);
+				ret = -EPERM;
+				goto out_unlock;
+			}
+		} else {
+			/* Request is for Default window, ensure there is no DDW if there is a
+			 * need to reset. reset-pe otherwise removes the DDW also
+			 */
+			default_prop = of_get_property(pdn, "ibm,dma-window", NULL);
+			if (!default_prop) {
+				if (find_existing_ddw(pdn, &pdev->dev.archdata.dma_offset, &len,
+						      &direct_mapping)) {
+					dev_warn(&pdev->dev, "%pOF: Attempt to create window#0 when 64-bit window is present. Preventing the attempt as that would destroy the 64-bit window",
+						 pdn);
+					ret = -EPERM;
+					goto out_unlock;
+				}
+
+				restore_default_dma_window(pdev, pdn);
+
+				default_prop = of_get_property(pdn, "ibm,dma-window", NULL);
+				of_parse_dma_window(pdn, default_prop, &liobn, &offset, &size);
+				/* Limit the default window size to window_size */
+				iommu_table_setparms_common(tbl, pci->phb->bus->number, liobn,
+							    offset, 1UL << window_shift,
+							    IOMMU_PAGE_SHIFT_4K, NULL,
+							    &iommu_table_lpar_multi_ops);
+				iommu_init_table(tbl, pci->phb->node, start, end);
+
+				table_group->tables[0] = tbl;
+
+				mutex_unlock(&dma_win_init_mutex);
+
+				goto exit;
+			}
+		}
+	}
+
+	ret = of_property_read_u32_array(pdn, "ibm,ddw-applicable",
+				&ddw_avail[0], DDW_APPLICABLE_SIZE);
+	if (ret) {
+		dev_info(&pdev->dev, "ibm,ddw-applicable not found\n");
+		goto out_failed;
+	}
+	ret = -ENODEV;
+
+	pr_err("%s: Calling query %pOF\n", __func__, pdn);
+	ret = query_ddw(pdev, ddw_avail, &query, pdn);
+	if (ret)
+		goto out_failed;
+	ret = -ENODEV;
+
+	len = window_shift;
+	if (query.largest_available_block < (1ULL << (len - page_shift))) {
+		dev_dbg(&pdev->dev, "can't map window 0x%llx with %llu %llu-sized pages\n",
+				1ULL << len, query.largest_available_block,
+				1ULL << page_shift);
+		ret = -EINVAL; /* Retry with smaller window size */
+		goto out_unlock;
+	}
+
+	if (create_ddw(pdev, ddw_avail, &create, page_shift, len)) {
+		pr_err("%s: Create ddw failed %pOF\n", __func__, pdn);
+		goto out_failed;
+	}
+
+	win_addr = ((u64)create.addr_hi << 32) | create.addr_lo;
+	win64 = ddw_property_create(DMA64_PROPNAME, create.liobn, win_addr, page_shift, len);
+	if (!win64)
+		goto remove_window;
+
+	ret = of_add_property(pdn, win64);
+	if (ret) {
+		dev_err(&pdev->dev, "unable to add DMA window property for %pOF: %ld", pdn, ret);
+		dump_stack();
+		goto free_property;
+	}
+	ret = -ENODEV;
+
+	window = ddw_list_new_entry(pdn, win64->value);
+	if (!window)
+		goto remove_property;
+
+	window->direct = false;
+
+	for (i = 0; i < ARRAY_SIZE(pci->phb->mem_resources); i++) {
+		const unsigned long mask = IORESOURCE_MEM_64 | IORESOURCE_MEM;
+
+		/* Look for MMIO32 */
+		if ((pci->phb->mem_resources[i].flags & mask) == IORESOURCE_MEM) {
+			start = pci->phb->mem_resources[i].start;
+			end = pci->phb->mem_resources[i].end;
+				break;
+		}
+	}
+
+	/* New table for using DDW instead of the default DMA window */
+	iommu_table_setparms_common(tbl, pci->phb->bus->number, create.liobn, win_addr,
+				    1UL << len, page_shift, NULL, &iommu_table_lpar_multi_ops);
+	iommu_init_table(tbl, pci->phb->node, start, end);
+
+	pci->table_group->tables[num] = tbl;
+	set_iommu_table_base(&pdev->dev, tbl);
+	pdev->dev.archdata.dma_offset = win_addr;
+
+	spin_lock(&dma_win_list_lock);
+	list_add(&window->list, &dma_win_list);
+	spin_unlock(&dma_win_list_lock);
+
+	mutex_unlock(&dma_win_init_mutex);
+
+	goto exit;
+
+remove_property:
+	of_remove_property(pdn, win64);
+free_property:
+	kfree(win64->name);
+	kfree(win64->value);
+	kfree(win64);
+remove_window:
+	__remove_dma_window(pdn, ddw_avail, create.liobn);
+
+out_failed:
+	fpdn = kzalloc(sizeof(*fpdn), GFP_KERNEL);
+	if (!fpdn)
+		goto out_unlock;
+	fpdn->pdn = pdn;
+	list_add(&fpdn->list, &failed_ddw_pdn_list);
+
+out_unlock:
+	mutex_unlock(&dma_win_init_mutex);
+
+	return ret;
+exit:
+	/* Allocate the userspace view */
+	pseries_tce_iommu_userspace_view_alloc(tbl);
+	tbl->it_allocated_size = spapr_tce_get_table_size(page_shift, window_size, levels);
+
 	*ptbl = iommu_tce_table_get(tbl);
+
 	return 0;
 }
 
+static bool is_default_window_table(struct iommu_table_group *table_group, struct iommu_table *tbl)
+{
+	if (((tbl->it_size << tbl->it_page_shift)  <= table_group->tce32_size) &&
+	    (tbl->it_page_shift == IOMMU_PAGE_SHIFT_4K))
+		return true;
+
+	return false;
+}
+
 static long spapr_tce_set_window(struct iommu_table_group *table_group,
 				 int num, struct iommu_table *tbl)
 {
@@ -1794,43 +2161,135 @@  static long spapr_tce_set_window(struct iommu_table_group *table_group,
 
 static long spapr_tce_unset_window(struct iommu_table_group *table_group, int num)
 {
-	return 0;
+	struct pci_dev *pdev = iommu_group_get_first_pci_dev(table_group->group);
+	struct device_node *dn = pci_device_to_OF_node(pdev), *pdn;
+	struct iommu_table *tbl = table_group->tables[num];
+	struct failed_ddw_pdn *fpdn;
+	struct dma_win *window;
+	const char *win_name;
+	struct pci_dn *pci;
+	int ret = -ENODEV;
+
+	mutex_lock(&dma_win_init_mutex);
+
+	if ((num == 0) && is_default_window_table(table_group, tbl))
+		win_name = "ibm,dma-window";
+	else
+		win_name = DMA64_PROPNAME;
+
+	pdn = pci_dma_find(dn, NULL);
+	if (!pdn || !PCI_DN(pdn)) { /* Niether of 32s|64-bit exist! */
+		dev_warn(&pdev->dev, "No dma-windows exist for the node %pOF\n", pdn);
+		goto out_failed;
+	}
+	pci = PCI_DN(pdn);
+
+	/* Dont clear the TCEs, User should have done it */
+	if (remove_dma_window_named(pdn, true, win_name, false)) {
+		pr_err("%s: The existing DDW removal failed for node %pOF\n", __func__, pdn);
+		goto out_failed; /* Could not remove it either! */
+	}
+
+	if (strcmp(win_name, DMA64_PROPNAME) == 0) {
+		spin_lock(&dma_win_list_lock);
+		list_for_each_entry(window, &dma_win_list, list) {
+			if (window->device == pdn) {
+				list_del(&window->list);
+				kfree(window);
+				break;
+			}
+		}
+		spin_unlock(&dma_win_list_lock);
+	}
+
+	iommu_tce_table_put(table_group->tables[num]);
+	table_group->tables[num] = NULL;
+
+	ret = 0;
+
+	goto out_unlock;
+
+out_failed:
+	fpdn = kzalloc(sizeof(*fpdn), GFP_KERNEL);
+	if (!fpdn)
+		goto out_unlock;
+	fpdn->pdn = pdn;
+	list_add(&fpdn->list, &failed_ddw_pdn_list);
+
+out_unlock:
+	mutex_unlock(&dma_win_init_mutex);
+
+	return ret;
 }
 
-static long spapr_tce_take_ownership(struct iommu_table_group *table_group)
+static long spapr_tce_take_ownership(struct iommu_table_group *table_group, struct device *dev)
 {
-	int i, j, rc = 0;
+	struct iommu_table *tbl = table_group->tables[0];
+	struct pci_dev *pdev = to_pci_dev(dev);
+	struct device_node *dn = pci_device_to_OF_node(pdev);
+	struct device_node *pdn;
 
-	for (i = 0; i < IOMMU_TABLE_GROUP_MAX_TABLES; ++i) {
-		struct iommu_table *tbl = table_group->tables[i];
+	/* SRIOV VFs using direct map by the host driver OR multifunction devices
+	 * where the ownership was taken on the attempt by the first function
+	 */
+	if (!tbl && (table_group->max_dynamic_windows_supported != 1))
+		return 0;
 
-		if (!tbl || !tbl->it_map)
-			continue;
+	mutex_lock(&dma_win_init_mutex);
 
-		rc = iommu_take_ownership(tbl);
-		if (!rc)
-			continue;
+	pdn = pci_dma_find(dn, NULL);
+	if (!pdn || !PCI_DN(pdn)) { /* Niether of 32s|64-bit exist! */
+		dev_warn(&pdev->dev, "No dma-windows exist for the node %pOF\n", pdn);
+		mutex_unlock(&dma_win_init_mutex);
+		return -1;
+	}
+
+	/*
+	 * Though rtas call reset-pe removes the DDW, it doesn't clear the entries on the table
+	 * if there are any. In case of direct map, the entries will be left over, which
+	 * is fine for PEs with 2 DMA windows where the second window is created with create-pe
+	 * at which point the table is cleared. However, on VFs having only one DMA window, the
+	 * default window would end up seeing the entries left over from the direct map done
+	 * on the second window. So, remove the ddw explicitly so that clean_dma_window()
+	 * cleans up the entries if any.
+	 */
+	if (remove_dynamic_dma_windows(pdev, pdn)) {
+		dev_warn(&pdev->dev, "The existing DDW removal failed for node %pOF\n", pdn);
+		mutex_unlock(&dma_win_init_mutex);
+		return -1;
+	}
 
-		for (j = 0; j < i; ++j)
-			iommu_release_ownership(table_group->tables[j]);
-		return rc;
+	/* The table_group->tables[0] is not null now, it must be the default window
+	 * Remove it, let the userspace create it as it needs.
+	 */
+	if (table_group->tables[0]) {
+		remove_dma_window_named(pdn, true, "ibm,dma-window", true);
+		iommu_tce_table_put(tbl);
+		table_group->tables[0] = NULL;
 	}
+	set_iommu_table_base(dev, NULL);
+
+	mutex_unlock(&dma_win_init_mutex);
+
 	return 0;
 }
 
-static void spapr_tce_release_ownership(struct iommu_table_group *table_group)
+static void spapr_tce_release_ownership(struct iommu_table_group *table_group, struct device *dev)
 {
-	int i;
+	struct iommu_table *tbl = table_group->tables[0];
 
-	for (i = 0; i < IOMMU_TABLE_GROUP_MAX_TABLES; ++i) {
-		struct iommu_table *tbl = table_group->tables[i];
+	if (tbl) { /* Default window already restored */
+		return;
+	}
 
-		if (!tbl)
-			continue;
+	mutex_lock(&dma_win_init_mutex);
 
-		if (tbl->it_map)
-			iommu_release_ownership(tbl);
-	}
+	/* Restore the default window */
+	pseries_setup_default_iommu_config(table_group, dev);
+
+	mutex_unlock(&dma_win_init_mutex);
+
+	return;
 }
 
 struct iommu_table_group_ops spapr_tce_table_group_ops = {
@@ -1903,8 +2362,8 @@  static int iommu_reconfig_notifier(struct notifier_block *nb, unsigned long acti
 		 * we have to remove the property when releasing
 		 * the device node.
 		 */
-		if (remove_ddw(np, false, DIRECT64_PROPNAME))
-			remove_ddw(np, false, DMA64_PROPNAME);
+		if (remove_dma_window_named(np, false, DIRECT64_PROPNAME, true))
+			remove_dma_window_named(np, false, DMA64_PROPNAME, true);
 
 		if (pci && pci->table_group)
 			iommu_pseries_free_group(pci->table_group,