diff mbox series

[v3,6/6] powerpc/iommu: Reimplement the iommu_table_group_ops for pSeries

Message ID 171810901192.1721.18057294492426295643.stgit@linux.ibm.com (mailing list archive)
State New, archived
Headers show
Series powerpc: pSeries: vfio: iommu: Re-enable support for SPAPR TCE VFIO | expand

Commit Message

Shivaprasad G Bhat June 11, 2024, 12:30 p.m. UTC
PPC64 IOMMU API defines iommu_table_group_ops which handles DMA
windows for PEs, their ownership transfer, create/set/unset the TCE
tables for the Dynamic DMA wundows(DDW). VFIOS uses these APIs for
support on POWER.

The commit 9d67c9433509 ("powerpc/iommu: Add "borrowing"
iommu_table_group_ops") implemented partial support for this API with
"borrow" mechanism wherein the DMA windows if created already by the
host driver, they would be available for VFIO to use. Also, it didn't
have the support to control/modify the window size or the IO page
size.

The current patch implements all the necessary iommu_table_group_ops
APIs there by avoiding the "borrrowing". So, just the way it is on the
PowerNV platform, with this patch the iommu table group ownership is
transferred to the VFIO PPC subdriver, the iommu table, DMA windows
creation/deletion all driven through the APIs.

The pSeries uses the query-pe-dma-window, create-pe-dma-window and
reset-pe-dma-window RTAS calls for DMA window creation, deletion and
reset to defaul. The RTAs calls do show some minor differences to the
way things are to be handled on the pSeries which are listed below.

* On pSeries, the default DMA window size is "fixed" cannot be custom
sized as requested by the user. For non-SRIOV VFs, It is fixed at 2GB
and for SRIOV VFs, its variable sized based on the capacity assigned
to it during the VF assignment to the LPAR. So, for the  default DMA
window alone the size if requested less than tce32_size, the smaller
size is enforced using the iommu table->it_size.

* The DMA start address for 32-bit window is 0, and for the 64-bit
window in case of PowerNV is hardcoded to TVE select (bit 59) at 512PiB
offset. This address is returned at the time of create_table() API call
(even before the window is created), the subsequent set_window() call
actually opens the DMA window. On pSeries, the DMA start address for
32-bit window is known from the 'ibm,dma-window' DT property. However,
the 64-bit window start address is not known until the create-pe-dma
RTAS call is made. So, the create_table() which returns the DMA window
start address actually opens the DMA window and returns the DMA start
address as returned by the Hypervisor for the create-pe-dma RTAS call.

* The reset-pe-dma RTAS call resets the DMA windows and restores the
default DMA window, however it does not clear the TCE table entries
if there are any. In case of ownership transfer from platform domain
which used direct mapping, the patch chooses remove-pe-dma instead of
reset-pe for the 64-bit window intentionally so that the
clear_dma_window() is called.

Other than the DMA window management changes mentioned above, the
patch also brings back the userspace view for the single level TCE
as it existed before commit 090bad39b237a ("powerpc/powernv: Add
indirect levels to it_userspace") along with the relavent
refactoring.

Signed-off-by: Shivaprasad G Bhat <sbhat@linux.ibm.com>
---
 arch/powerpc/include/asm/iommu.h          |    4 
 arch/powerpc/kernel/iommu.c               |    4 
 arch/powerpc/platforms/powernv/pci-ioda.c |    6 
 arch/powerpc/platforms/pseries/iommu.c    |  631 +++++++++++++++++++++++++----
 4 files changed, 547 insertions(+), 98 deletions(-)

Comments

kernel test robot June 12, 2024, 9:11 a.m. UTC | #1
Hi Shivaprasad,

kernel test robot noticed the following build warnings:

[auto build test WARNING on powerpc/fixes]
[also build test WARNING on awilliam-vfio/next awilliam-vfio/for-linus linus/master v6.10-rc3]
[cannot apply to powerpc/next next-20240612]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Shivaprasad-G-Bhat/powerpc-iommu-Move-pSeries-specific-functions-to-pseries-iommu-c/20240611-203313
base:   https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git fixes
patch link:    https://lore.kernel.org/r/171810901192.1721.18057294492426295643.stgit%40linux.ibm.com
patch subject: [PATCH v3 6/6] powerpc/iommu: Reimplement the iommu_table_group_ops for pSeries
config: powerpc64-randconfig-001-20240612 (https://download.01.org/0day-ci/archive/20240612/202406121640.yr6LK5HJ-lkp@intel.com/config)
compiler: powerpc64-linux-gcc (GCC) 13.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240612/202406121640.yr6LK5HJ-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202406121640.yr6LK5HJ-lkp@intel.com/

All warnings (new ones prefixed by >>):

   arch/powerpc/platforms/pseries/iommu.c: In function 'spapr_tce_create_table':
>> arch/powerpc/platforms/pseries/iommu.c:1953:22: warning: variable 'entries_shift' set but not used [-Wunused-but-set-variable]
    1953 |         unsigned int entries_shift;
         |                      ^~~~~~~~~~~~~
   arch/powerpc/platforms/pseries/iommu.c: In function 'spapr_tce_unset_window':
>> arch/powerpc/platforms/pseries/iommu.c:2166:24: warning: variable 'pci' set but not used [-Wunused-but-set-variable]
    2166 |         struct pci_dn *pci;
         |                        ^~~


vim +/entries_shift +1953 arch/powerpc/platforms/pseries/iommu.c

  1940	
  1941	static long spapr_tce_create_table(struct iommu_table_group *table_group, int num,
  1942					   __u32 page_shift, __u64 window_size, __u32 levels,
  1943					   struct iommu_table **ptbl)
  1944	{
  1945		struct pci_dev *pdev = iommu_group_get_first_pci_dev(table_group->group);
  1946		u32 ddw_avail[DDW_APPLICABLE_SIZE];
  1947		struct ddw_create_response create;
  1948		unsigned long liobn, offset, size;
  1949		unsigned long start = 0, end = 0;
  1950		struct ddw_query_response query;
  1951		const __be32 *default_prop;
  1952		struct failed_ddw_pdn *fpdn;
> 1953		unsigned int entries_shift;
  1954		unsigned int window_shift;
  1955		struct device_node *pdn;
  1956		struct iommu_table *tbl;
  1957		struct dma_win *window;
  1958		struct property *win64;
  1959		struct pci_dn *pci;
  1960		u64 win_addr;
  1961		int len, i;
  1962		long ret;
  1963	
  1964		if (!is_power_of_2(window_size) || levels > 1)
  1965			return -EINVAL;
  1966	
  1967		window_shift = order_base_2(window_size);
  1968		entries_shift = window_shift - page_shift;
  1969	
  1970		mutex_lock(&dma_win_init_mutex);
  1971	
  1972		ret = -ENODEV;
  1973	
  1974		pdn = pci_dma_find_parent_node(pdev, table_group);
  1975		if (!pdn || !PCI_DN(pdn)) { /* Niether of 32s|64-bit exist! */
  1976			dev_warn(&pdev->dev, "No dma-windows exist for the node %pOF\n", pdn);
  1977			goto out_failed;
  1978		}
  1979		pci = PCI_DN(pdn);
  1980	
  1981		/* If the enable DDW failed for the pdn, dont retry! */
  1982		list_for_each_entry(fpdn, &failed_ddw_pdn_list, list) {
  1983			if (fpdn->pdn == pdn) {
  1984				dev_info(&pdev->dev, "%pOF in failed DDW device list\n", pdn);
  1985				goto out_unlock;
  1986			}
  1987		}
  1988	
  1989		tbl = iommu_pseries_alloc_table(pci->phb->node);
  1990		if (!tbl) {
  1991			dev_dbg(&pdev->dev, "couldn't create new IOMMU table\n");
  1992			goto out_unlock;
  1993		}
  1994	
  1995		if (num == 0) {
  1996			bool direct_mapping;
  1997			/* The request is not for default window? Ensure there is no DDW window already */
  1998			if (!is_default_window_request(table_group, page_shift, window_size)) {
  1999				if (find_existing_ddw(pdn, &pdev->dev.archdata.dma_offset, &len,
  2000						      &direct_mapping)) {
  2001					dev_warn(&pdev->dev, "%pOF: 64-bit window already present.", pdn);
  2002					ret = -EPERM;
  2003					goto out_unlock;
  2004				}
  2005			} else {
  2006				/* Request is for Default window, ensure there is no DDW if there is a
  2007				 * need to reset. reset-pe otherwise removes the DDW also
  2008				 */
  2009				default_prop = of_get_property(pdn, "ibm,dma-window", NULL);
  2010				if (!default_prop) {
  2011					if (find_existing_ddw(pdn, &pdev->dev.archdata.dma_offset, &len,
  2012							      &direct_mapping)) {
  2013						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",
  2014							 pdn);
  2015						ret = -EPERM;
  2016						goto out_unlock;
  2017					}
  2018	
  2019					restore_default_dma_window(pdev, pdn);
  2020	
  2021					default_prop = of_get_property(pdn, "ibm,dma-window", NULL);
  2022					of_parse_dma_window(pdn, default_prop, &liobn, &offset, &size);
  2023					/* Limit the default window size to window_size */
  2024					iommu_table_setparms_common(tbl, pci->phb->bus->number, liobn,
  2025								    offset, 1UL << window_shift,
  2026								    IOMMU_PAGE_SHIFT_4K, NULL,
  2027								    &iommu_table_lpar_multi_ops);
  2028					iommu_init_table(tbl, pci->phb->node, start, end);
  2029	
  2030					table_group->tables[0] = tbl;
  2031	
  2032					mutex_unlock(&dma_win_init_mutex);
  2033	
  2034					goto exit;
  2035				}
  2036			}
  2037		}
  2038	
  2039		ret = of_property_read_u32_array(pdn, "ibm,ddw-applicable",
  2040					&ddw_avail[0], DDW_APPLICABLE_SIZE);
  2041		if (ret) {
  2042			dev_info(&pdev->dev, "ibm,ddw-applicable not found\n");
  2043			goto out_failed;
  2044		}
  2045		ret = -ENODEV;
  2046	
  2047		pr_err("%s: Calling query %pOF\n", __func__, pdn);
  2048		ret = query_ddw(pdev, ddw_avail, &query, pdn);
  2049		if (ret)
  2050			goto out_failed;
  2051		ret = -ENODEV;
  2052	
  2053		len = window_shift;
  2054		if (query.largest_available_block < (1ULL << (len - page_shift))) {
  2055			dev_dbg(&pdev->dev, "can't map window 0x%llx with %llu %llu-sized pages\n",
  2056					1ULL << len, query.largest_available_block,
  2057					1ULL << page_shift);
  2058			ret = -EINVAL; /* Retry with smaller window size */
  2059			goto out_unlock;
  2060		}
  2061	
  2062		if (create_ddw(pdev, ddw_avail, &create, page_shift, len)) {
  2063			pr_err("%s: Create ddw failed %pOF\n", __func__, pdn);
  2064			goto out_failed;
  2065		}
  2066	
  2067		win_addr = ((u64)create.addr_hi << 32) | create.addr_lo;
  2068		win64 = ddw_property_create(DMA64_PROPNAME, create.liobn, win_addr, page_shift, len);
  2069		if (!win64)
  2070			goto remove_window;
  2071	
  2072		ret = of_add_property(pdn, win64);
  2073		if (ret) {
  2074			dev_err(&pdev->dev, "unable to add DMA window property for %pOF: %ld", pdn, ret);
  2075			goto free_property;
  2076		}
  2077		ret = -ENODEV;
  2078	
  2079		window = ddw_list_new_entry(pdn, win64->value);
  2080		if (!window)
  2081			goto remove_property;
  2082	
  2083		window->direct = false;
  2084	
  2085		for (i = 0; i < ARRAY_SIZE(pci->phb->mem_resources); i++) {
  2086			const unsigned long mask = IORESOURCE_MEM_64 | IORESOURCE_MEM;
  2087	
  2088			/* Look for MMIO32 */
  2089			if ((pci->phb->mem_resources[i].flags & mask) == IORESOURCE_MEM) {
  2090				start = pci->phb->mem_resources[i].start;
  2091				end = pci->phb->mem_resources[i].end;
  2092					break;
  2093			}
  2094		}
  2095	
  2096		/* New table for using DDW instead of the default DMA window */
  2097		iommu_table_setparms_common(tbl, pci->phb->bus->number, create.liobn, win_addr,
  2098					    1UL << len, page_shift, NULL, &iommu_table_lpar_multi_ops);
  2099		iommu_init_table(tbl, pci->phb->node, start, end);
  2100	
  2101		pci->table_group->tables[num] = tbl;
  2102		set_iommu_table_base(&pdev->dev, tbl);
  2103		pdev->dev.archdata.dma_offset = win_addr;
  2104	
  2105		spin_lock(&dma_win_list_lock);
  2106		list_add(&window->list, &dma_win_list);
  2107		spin_unlock(&dma_win_list_lock);
  2108	
  2109		mutex_unlock(&dma_win_init_mutex);
  2110	
  2111		goto exit;
  2112	
  2113	remove_property:
  2114		of_remove_property(pdn, win64);
  2115	free_property:
  2116		kfree(win64->name);
  2117		kfree(win64->value);
  2118		kfree(win64);
  2119	remove_window:
  2120		__remove_dma_window(pdn, ddw_avail, create.liobn);
  2121	
  2122	out_failed:
  2123		fpdn = kzalloc(sizeof(*fpdn), GFP_KERNEL);
  2124		if (!fpdn)
  2125			goto out_unlock;
  2126		fpdn->pdn = pdn;
  2127		list_add(&fpdn->list, &failed_ddw_pdn_list);
  2128	
  2129	out_unlock:
  2130		mutex_unlock(&dma_win_init_mutex);
  2131	
  2132		return ret;
  2133	exit:
  2134		/* Allocate the userspace view */
  2135		pseries_tce_iommu_userspace_view_alloc(tbl);
  2136		tbl->it_allocated_size = spapr_tce_get_table_size(page_shift, window_size, levels);
  2137	
  2138		*ptbl = iommu_tce_table_get(tbl);
  2139	
  2140		return 0;
  2141	}
  2142
kernel test robot June 14, 2024, 1:24 p.m. UTC | #2
Hi Shivaprasad,

kernel test robot noticed the following build errors:

[auto build test ERROR on powerpc/fixes]
[also build test ERROR on awilliam-vfio/next awilliam-vfio/for-linus linus/master v6.10-rc3]
[cannot apply to powerpc/next next-20240613]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Shivaprasad-G-Bhat/powerpc-iommu-Move-pSeries-specific-functions-to-pseries-iommu-c/20240611-203313
base:   https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git fixes
patch link:    https://lore.kernel.org/r/171810901192.1721.18057294492426295643.stgit%40linux.ibm.com
patch subject: [PATCH v3 6/6] powerpc/iommu: Reimplement the iommu_table_group_ops for pSeries
config: powerpc64-randconfig-r133-20240614 (https://download.01.org/0day-ci/archive/20240614/202406142110.r97Ts8Xm-lkp@intel.com/config)
compiler: clang version 19.0.0git (https://github.com/llvm/llvm-project 78ee473784e5ef6f0b19ce4cb111fb6e4d23c6b2)
reproduce: (https://download.01.org/0day-ci/archive/20240614/202406142110.r97Ts8Xm-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202406142110.r97Ts8Xm-lkp@intel.com/

All errors (new ones prefixed by >>):

   In file included from arch/powerpc/platforms/pseries/iommu.c:16:
   In file included from include/linux/mm.h:2253:
   include/linux/vmstat.h:500:43: warning: arithmetic between different enumeration types ('enum zone_stat_item' and 'enum numa_stat_item') [-Wenum-enum-conversion]
     500 |         return vmstat_text[NR_VM_ZONE_STAT_ITEMS +
         |                            ~~~~~~~~~~~~~~~~~~~~~ ^
     501 |                            item];
         |                            ~~~~
   include/linux/vmstat.h:507:43: warning: arithmetic between different enumeration types ('enum zone_stat_item' and 'enum numa_stat_item') [-Wenum-enum-conversion]
     507 |         return vmstat_text[NR_VM_ZONE_STAT_ITEMS +
         |                            ~~~~~~~~~~~~~~~~~~~~~ ^
     508 |                            NR_VM_NUMA_EVENT_ITEMS +
         |                            ~~~~~~~~~~~~~~~~~~~~~~
   include/linux/vmstat.h:514:36: warning: arithmetic between different enumeration types ('enum node_stat_item' and 'enum lru_list') [-Wenum-enum-conversion]
     514 |         return node_stat_name(NR_LRU_BASE + lru) + 3; // skip "nr_"
         |                               ~~~~~~~~~~~ ^ ~~~
   include/linux/vmstat.h:519:43: warning: arithmetic between different enumeration types ('enum zone_stat_item' and 'enum numa_stat_item') [-Wenum-enum-conversion]
     519 |         return vmstat_text[NR_VM_ZONE_STAT_ITEMS +
         |                            ~~~~~~~~~~~~~~~~~~~~~ ^
     520 |                            NR_VM_NUMA_EVENT_ITEMS +
         |                            ~~~~~~~~~~~~~~~~~~~~~~
   include/linux/vmstat.h:528:43: warning: arithmetic between different enumeration types ('enum zone_stat_item' and 'enum numa_stat_item') [-Wenum-enum-conversion]
     528 |         return vmstat_text[NR_VM_ZONE_STAT_ITEMS +
         |                            ~~~~~~~~~~~~~~~~~~~~~ ^
     529 |                            NR_VM_NUMA_EVENT_ITEMS +
         |                            ~~~~~~~~~~~~~~~~~~~~~~
>> arch/powerpc/platforms/pseries/iommu.c:1839:47: error: use of undeclared identifier 'dev_has_iommu_table'; did you mean 'device_iommu_capable'?
    1839 |         ret = iommu_group_for_each_dev(group, &pdev, dev_has_iommu_table);
         |                                                      ^~~~~~~~~~~~~~~~~~~
         |                                                      device_iommu_capable
   include/linux/iommu.h:1079:20: note: 'device_iommu_capable' declared here
    1079 | static inline bool device_iommu_capable(struct device *dev, enum iommu_cap cap)
         |                    ^
   arch/powerpc/platforms/pseries/iommu.c:1953:15: warning: variable 'entries_shift' set but not used [-Wunused-but-set-variable]
    1953 |         unsigned int entries_shift;
         |                      ^
   arch/powerpc/platforms/pseries/iommu.c:2166:17: warning: variable 'pci' set but not used [-Wunused-but-set-variable]
    2166 |         struct pci_dn *pci;
         |                        ^
   7 warnings and 1 error generated.


vim +1839 arch/powerpc/platforms/pseries/iommu.c

  1829	
  1830	static struct pci_dev *iommu_group_get_first_pci_dev(struct iommu_group *group)
  1831	{
  1832		struct pci_dev *pdev = NULL;
  1833		int ret;
  1834	
  1835		/* No IOMMU group ? */
  1836		if (!group)
  1837			return NULL;
  1838	
> 1839		ret = iommu_group_for_each_dev(group, &pdev, dev_has_iommu_table);
  1840		if (!ret || !pdev)
  1841			return NULL;
  1842		return pdev;
  1843	}
  1844
diff mbox series

Patch

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 ed8204cfa319..76381e14e800 100644
--- a/arch/powerpc/kernel/iommu.c
+++ b/arch/powerpc/kernel/iommu.c
@@ -1171,7 +1171,7 @@  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;
@@ -1199,7 +1199,7 @@  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 cffa64cf60e7..29211944565a 100644
--- a/arch/powerpc/platforms/pseries/iommu.c
+++ b/arch/powerpc/platforms/pseries/iommu.c
@@ -21,6 +21,7 @@ 
 #include <linux/dma-mapping.h>
 #include <linux/crash_dump.h>
 #include <linux/memory.h>
+#include <linux/vmalloc.h>
 #include <linux/of.h>
 #include <linux/of_address.h>
 #include <linux/iommu.h>
@@ -54,57 +55,6 @@  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 +146,7 @@  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 +165,37 @@  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 +610,7 @@  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 +719,45 @@  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.
@@ -963,7 +972,7 @@  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;
@@ -971,11 +980,44 @@  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 void copy_property(struct device_node *pdn, const char *from, const char *to)
+{
+	struct property *src, *dst;
+
+	src = of_find_property(pdn, from, NULL);
+	if (!src)
+		return;
+
+	dst = kzalloc(sizeof(*dst), GFP_KERNEL);
+	if (!dst)
+		return;
+
+	dst->name = kstrdup(to, GFP_KERNEL);
+	dst->value = kmemdup(src->value, src->length, GFP_KERNEL);
+	dst->length = src->length;
+	if (!dst->name || !dst->value)
+		return;
+
+	if (of_add_property(pdn, dst)) {
+		pr_err("Unable to add DMA window property for %pOF", pdn);
+		goto free_prop;
+	}
+
+	return;
+
+free_prop:
+	kfree(dst->name);
+	kfree(dst->value);
+	kfree(dst);
+}
+
+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];
@@ -990,13 +1032,20 @@  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;
 
+	/* Default window property if removed is lost as reset-pe doesn't restore it.
+	 * Though FDT has a copy of it, the DLPAR hotplugged devices will not have a
+	 * node on FDT until next reboot. So, back it up.
+	 */
+	if ((strcmp(win_name, "ibm,dma-window") == 0) &&
+	    !of_find_property(np, "ibm,dma-window-saved", NULL))
+		copy_property(np, win_name, "ibm,dma-window-saved");
+
 	ret = of_remove_property(np, win);
 	if (ret)
 		pr_warn("%pOF: failed to remove DMA window property: %d\n",
@@ -1054,7 +1103,7 @@  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;
 		}
 
@@ -1431,7 +1480,7 @@  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 */
@@ -1568,6 +1617,8 @@  static bool enable_ddw(struct pci_dev *dev, struct device_node *pdn)
 
 	if (default_win_removed) {
 		/* default_win is valid here because default_win_removed == true */
+		if (!of_find_property(pdn, "ibm,dma-window-saved", NULL))
+			copy_property(pdn, "ibm,dma-window", "ibm,dma-window-saved");
 		of_remove_property(pdn, default_win);
 		dev_info(&dev->dev, "Removed default DMA window for %pOF\n", pdn);
 	}
@@ -1776,24 +1827,328 @@  static unsigned long spapr_tce_get_table_size(__u32 page_shift,
 	return size;
 }
 
+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)
+{
+	reset_dma_window(pdev, pdn);
+	copy_property(pdn, "ibm,dma-window-saved", "ibm,dma-window");
+}
+
+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);
+		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)
 {
@@ -1802,43 +2157,135 @@  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;
+	}
 
-		for (j = 0; j < i; ++j)
-			iommu_release_ownership(table_group->tables[j]);
-		return rc;
+	/*
+	 * 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;
 	}
+
+	/* 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 = {
@@ -1911,8 +2358,8 @@  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,