Initial import

1 files changed, 1275 insertions, 0 deletions

diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
new file mode 100644
index 000000000..d4f527e56
--- /dev/null
+++ b/drivers/iommu/iommu.c
@@ -0,0 +1,1275 @@
+/*
+ * Copyright (C) 2007-2008 Advanced Micro Devices, Inc.
+ * Author: Joerg Roedel <jroedel@suse.de>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published
+ * by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
+ */
+
+#define pr_fmt(fmt)    "%s: " fmt, __func__
+
+#include <linux/device.h>
+#include <linux/kernel.h>
+#include <linux/bug.h>
+#include <linux/types.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/errno.h>
+#include <linux/iommu.h>
+#include <linux/idr.h>
+#include <linux/notifier.h>
+#include <linux/err.h>
+#include <linux/pci.h>
+#include <linux/bitops.h>
+#include <trace/events/iommu.h>
+
+static struct kset *iommu_group_kset;
+static struct ida iommu_group_ida;
+static struct mutex iommu_group_mutex;
+
+struct iommu_callback_data {
+	const struct iommu_ops *ops;
+};
+
+struct iommu_group {
+	struct kobject kobj;
+	struct kobject *devices_kobj;
+	struct list_head devices;
+	struct mutex mutex;
+	struct blocking_notifier_head notifier;
+	void *iommu_data;
+	void (*iommu_data_release)(void *iommu_data);
+	char *name;
+	int id;
+};
+
+struct iommu_device {
+	struct list_head list;
+	struct device *dev;
+	char *name;
+};
+
+struct iommu_group_attribute {
+	struct attribute attr;
+	ssize_t (*show)(struct iommu_group *group, char *buf);
+	ssize_t (*store)(struct iommu_group *group,
+			 const char *buf, size_t count);
+};
+
+#define IOMMU_GROUP_ATTR(_name, _mode, _show, _store)		\
+struct iommu_group_attribute iommu_group_attr_##_name =		\
+	__ATTR(_name, _mode, _show, _store)
+
+#define to_iommu_group_attr(_attr)	\
+	container_of(_attr, struct iommu_group_attribute, attr)
+#define to_iommu_group(_kobj)		\
+	container_of(_kobj, struct iommu_group, kobj)
+
+static ssize_t iommu_group_attr_show(struct kobject *kobj,
+				     struct attribute *__attr, char *buf)
+{
+	struct iommu_group_attribute *attr = to_iommu_group_attr(__attr);
+	struct iommu_group *group = to_iommu_group(kobj);
+	ssize_t ret = -EIO;
+
+	if (attr->show)
+		ret = attr->show(group, buf);
+	return ret;
+}
+
+static ssize_t iommu_group_attr_store(struct kobject *kobj,
+				      struct attribute *__attr,
+				      const char *buf, size_t count)
+{
+	struct iommu_group_attribute *attr = to_iommu_group_attr(__attr);
+	struct iommu_group *group = to_iommu_group(kobj);
+	ssize_t ret = -EIO;
+
+	if (attr->store)
+		ret = attr->store(group, buf, count);
+	return ret;
+}
+
+static const struct sysfs_ops iommu_group_sysfs_ops = {
+	.show = iommu_group_attr_show,
+	.store = iommu_group_attr_store,
+};
+
+static int iommu_group_create_file(struct iommu_group *group,
+				   struct iommu_group_attribute *attr)
+{
+	return sysfs_create_file(&group->kobj, &attr->attr);
+}
+
+static void iommu_group_remove_file(struct iommu_group *group,
+				    struct iommu_group_attribute *attr)
+{
+	sysfs_remove_file(&group->kobj, &attr->attr);
+}
+
+static ssize_t iommu_group_show_name(struct iommu_group *group, char *buf)
+{
+	return sprintf(buf, "%s\n", group->name);
+}
+
+static IOMMU_GROUP_ATTR(name, S_IRUGO, iommu_group_show_name, NULL);
+
+static void iommu_group_release(struct kobject *kobj)
+{
+	struct iommu_group *group = to_iommu_group(kobj);
+
+	if (group->iommu_data_release)
+		group->iommu_data_release(group->iommu_data);
+
+	mutex_lock(&iommu_group_mutex);
+	ida_remove(&iommu_group_ida, group->id);
+	mutex_unlock(&iommu_group_mutex);
+
+	kfree(group->name);
+	kfree(group);
+}
+
+static struct kobj_type iommu_group_ktype = {
+	.sysfs_ops = &iommu_group_sysfs_ops,
+	.release = iommu_group_release,
+};
+
+/**
+ * iommu_group_alloc - Allocate a new group
+ * @name: Optional name to associate with group, visible in sysfs
+ *
+ * This function is called by an iommu driver to allocate a new iommu
+ * group.  The iommu group represents the minimum granularity of the iommu.
+ * Upon successful return, the caller holds a reference to the supplied
+ * group in order to hold the group until devices are added.  Use
+ * iommu_group_put() to release this extra reference count, allowing the
+ * group to be automatically reclaimed once it has no devices or external
+ * references.
+ */
+struct iommu_group *iommu_group_alloc(void)
+{
+	struct iommu_group *group;
+	int ret;
+
+	group = kzalloc(sizeof(*group), GFP_KERNEL);
+	if (!group)
+		return ERR_PTR(-ENOMEM);
+
+	group->kobj.kset = iommu_group_kset;
+	mutex_init(&group->mutex);
+	INIT_LIST_HEAD(&group->devices);
+	BLOCKING_INIT_NOTIFIER_HEAD(&group->notifier);
+
+	mutex_lock(&iommu_group_mutex);
+
+again:
+	if (unlikely(0 == ida_pre_get(&iommu_group_ida, GFP_KERNEL))) {
+		kfree(group);
+		mutex_unlock(&iommu_group_mutex);
+		return ERR_PTR(-ENOMEM);
+	}
+
+	if (-EAGAIN == ida_get_new(&iommu_group_ida, &group->id))
+		goto again;
+
+	mutex_unlock(&iommu_group_mutex);
+
+	ret = kobject_init_and_add(&group->kobj, &iommu_group_ktype,
+				   NULL, "%d", group->id);
+	if (ret) {
+		mutex_lock(&iommu_group_mutex);
+		ida_remove(&iommu_group_ida, group->id);
+		mutex_unlock(&iommu_group_mutex);
+		kfree(group);
+		return ERR_PTR(ret);
+	}
+
+	group->devices_kobj = kobject_create_and_add("devices", &group->kobj);
+	if (!group->devices_kobj) {
+		kobject_put(&group->kobj); /* triggers .release & free */
+		return ERR_PTR(-ENOMEM);
+	}
+
+	/*
+	 * The devices_kobj holds a reference on the group kobject, so
+	 * as long as that exists so will the group.  We can therefore
+	 * use the devices_kobj for reference counting.
+	 */
+	kobject_put(&group->kobj);
+
+	return group;
+}
+EXPORT_SYMBOL_GPL(iommu_group_alloc);
+
+struct iommu_group *iommu_group_get_by_id(int id)
+{
+	struct kobject *group_kobj;
+	struct iommu_group *group;
+	const char *name;
+
+	if (!iommu_group_kset)
+		return NULL;
+
+	name = kasprintf(GFP_KERNEL, "%d", id);
+	if (!name)
+		return NULL;
+
+	group_kobj = kset_find_obj(iommu_group_kset, name);
+	kfree(name);
+
+	if (!group_kobj)
+		return NULL;
+
+	group = container_of(group_kobj, struct iommu_group, kobj);
+	BUG_ON(group->id != id);
+
+	kobject_get(group->devices_kobj);
+	kobject_put(&group->kobj);
+
+	return group;
+}
+EXPORT_SYMBOL_GPL(iommu_group_get_by_id);
+
+/**
+ * iommu_group_get_iommudata - retrieve iommu_data registered for a group
+ * @group: the group
+ *
+ * iommu drivers can store data in the group for use when doing iommu
+ * operations.  This function provides a way to retrieve it.  Caller
+ * should hold a group reference.
+ */
+void *iommu_group_get_iommudata(struct iommu_group *group)
+{
+	return group->iommu_data;
+}
+EXPORT_SYMBOL_GPL(iommu_group_get_iommudata);
+
+/**
+ * iommu_group_set_iommudata - set iommu_data for a group
+ * @group: the group
+ * @iommu_data: new data
+ * @release: release function for iommu_data
+ *
+ * iommu drivers can store data in the group for use when doing iommu
+ * operations.  This function provides a way to set the data after
+ * the group has been allocated.  Caller should hold a group reference.
+ */
+void iommu_group_set_iommudata(struct iommu_group *group, void *iommu_data,
+			       void (*release)(void *iommu_data))
+{
+	group->iommu_data = iommu_data;
+	group->iommu_data_release = release;
+}
+EXPORT_SYMBOL_GPL(iommu_group_set_iommudata);
+
+/**
+ * iommu_group_set_name - set name for a group
+ * @group: the group
+ * @name: name
+ *
+ * Allow iommu driver to set a name for a group.  When set it will
+ * appear in a name attribute file under the group in sysfs.
+ */
+int iommu_group_set_name(struct iommu_group *group, const char *name)
+{
+	int ret;
+
+	if (group->name) {
+		iommu_group_remove_file(group, &iommu_group_attr_name);
+		kfree(group->name);
+		group->name = NULL;
+		if (!name)
+			return 0;
+	}
+
+	group->name = kstrdup(name, GFP_KERNEL);
+	if (!group->name)
+		return -ENOMEM;
+
+	ret = iommu_group_create_file(group, &iommu_group_attr_name);
+	if (ret) {
+		kfree(group->name);
+		group->name = NULL;
+		return ret;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(iommu_group_set_name);
+
+/**
+ * iommu_group_add_device - add a device to an iommu group
+ * @group: the group into which to add the device (reference should be held)
+ * @dev: the device
+ *
+ * This function is called by an iommu driver to add a device into a
+ * group.  Adding a device increments the group reference count.
+ */
+int iommu_group_add_device(struct iommu_group *group, struct device *dev)
+{
+	int ret, i = 0;
+	struct iommu_device *device;
+
+	device = kzalloc(sizeof(*device), GFP_KERNEL);
+	if (!device)
+		return -ENOMEM;
+
+	device->dev = dev;
+
+	ret = sysfs_create_link(&dev->kobj, &group->kobj, "iommu_group");
+	if (ret) {
+		kfree(device);
+		return ret;
+	}
+
+	device->name = kasprintf(GFP_KERNEL, "%s", kobject_name(&dev->kobj));
+rename:
+	if (!device->name) {
+		sysfs_remove_link(&dev->kobj, "iommu_group");
+		kfree(device);
+		return -ENOMEM;
+	}
+
+	ret = sysfs_create_link_nowarn(group->devices_kobj,
+				       &dev->kobj, device->name);
+	if (ret) {
+		kfree(device->name);
+		if (ret == -EEXIST && i >= 0) {
+			/*
+			 * Account for the slim chance of collision
+			 * and append an instance to the name.
+			 */
+			device->name = kasprintf(GFP_KERNEL, "%s.%d",
+						 kobject_name(&dev->kobj), i++);
+			goto rename;
+		}
+
+		sysfs_remove_link(&dev->kobj, "iommu_group");
+		kfree(device);
+		return ret;
+	}
+
+	kobject_get(group->devices_kobj);
+
+	dev->iommu_group = group;
+
+	mutex_lock(&group->mutex);
+	list_add_tail(&device->list, &group->devices);
+	mutex_unlock(&group->mutex);
+
+	/* Notify any listeners about change to group. */
+	blocking_notifier_call_chain(&group->notifier,
+				     IOMMU_GROUP_NOTIFY_ADD_DEVICE, dev);
+
+	trace_add_device_to_group(group->id, dev);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(iommu_group_add_device);
+
+/**
+ * iommu_group_remove_device - remove a device from it's current group
+ * @dev: device to be removed
+ *
+ * This function is called by an iommu driver to remove the device from
+ * it's current group.  This decrements the iommu group reference count.
+ */
+void iommu_group_remove_device(struct device *dev)
+{
+	struct iommu_group *group = dev->iommu_group;
+	struct iommu_device *tmp_device, *device = NULL;
+
+	/* Pre-notify listeners that a device is being removed. */
+	blocking_notifier_call_chain(&group->notifier,
+				     IOMMU_GROUP_NOTIFY_DEL_DEVICE, dev);
+
+	mutex_lock(&group->mutex);
+	list_for_each_entry(tmp_device, &group->devices, list) {
+		if (tmp_device->dev == dev) {
+			device = tmp_device;
+			list_del(&device->list);
+			break;
+		}
+	}
+	mutex_unlock(&group->mutex);
+
+	if (!device)
+		return;
+
+	sysfs_remove_link(group->devices_kobj, device->name);
+	sysfs_remove_link(&dev->kobj, "iommu_group");
+
+	trace_remove_device_from_group(group->id, dev);
+
+	kfree(device->name);
+	kfree(device);
+	dev->iommu_group = NULL;
+	kobject_put(group->devices_kobj);
+}
+EXPORT_SYMBOL_GPL(iommu_group_remove_device);
+
+/**
+ * iommu_group_for_each_dev - iterate over each device in the group
+ * @group: the group
+ * @data: caller opaque data to be passed to callback function
+ * @fn: caller supplied callback function
+ *
+ * This function is called by group users to iterate over group devices.
+ * Callers should hold a reference count to the group during callback.
+ * The group->mutex is held across callbacks, which will block calls to
+ * iommu_group_add/remove_device.
+ */
+int iommu_group_for_each_dev(struct iommu_group *group, void *data,
+			     int (*fn)(struct device *, void *))
+{
+	struct iommu_device *device;
+	int ret = 0;
+
+	mutex_lock(&group->mutex);
+	list_for_each_entry(device, &group->devices, list) {
+		ret = fn(device->dev, data);
+		if (ret)
+			break;
+	}
+	mutex_unlock(&group->mutex);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(iommu_group_for_each_dev);
+
+/**
+ * iommu_group_get - Return the group for a device and increment reference
+ * @dev: get the group that this device belongs to
+ *
+ * This function is called by iommu drivers and users to get the group
+ * for the specified device.  If found, the group is returned and the group
+ * reference in incremented, else NULL.
+ */
+struct iommu_group *iommu_group_get(struct device *dev)
+{
+	struct iommu_group *group = dev->iommu_group;
+
+	if (group)
+		kobject_get(group->devices_kobj);
+
+	return group;
+}
+EXPORT_SYMBOL_GPL(iommu_group_get);
+
+/**
+ * iommu_group_put - Decrement group reference
+ * @group: the group to use
+ *
+ * This function is called by iommu drivers and users to release the
+ * iommu group.  Once the reference count is zero, the group is released.
+ */
+void iommu_group_put(struct iommu_group *group)
+{
+	if (group)
+		kobject_put(group->devices_kobj);
+}
+EXPORT_SYMBOL_GPL(iommu_group_put);
+
+/**
+ * iommu_group_register_notifier - Register a notifier for group changes
+ * @group: the group to watch
+ * @nb: notifier block to signal
+ *
+ * This function allows iommu group users to track changes in a group.
+ * See include/linux/iommu.h for actions sent via this notifier.  Caller
+ * should hold a reference to the group throughout notifier registration.
+ */
+int iommu_group_register_notifier(struct iommu_group *group,
+				  struct notifier_block *nb)
+{
+	return blocking_notifier_chain_register(&group->notifier, nb);
+}
+EXPORT_SYMBOL_GPL(iommu_group_register_notifier);
+
+/**
+ * iommu_group_unregister_notifier - Unregister a notifier
+ * @group: the group to watch
+ * @nb: notifier block to signal
+ *
+ * Unregister a previously registered group notifier block.
+ */
+int iommu_group_unregister_notifier(struct iommu_group *group,
+				    struct notifier_block *nb)
+{
+	return blocking_notifier_chain_unregister(&group->notifier, nb);
+}
+EXPORT_SYMBOL_GPL(iommu_group_unregister_notifier);
+
+/**
+ * iommu_group_id - Return ID for a group
+ * @group: the group to ID
+ *
+ * Return the unique ID for the group matching the sysfs group number.
+ */
+int iommu_group_id(struct iommu_group *group)
+{
+	return group->id;
+}
+EXPORT_SYMBOL_GPL(iommu_group_id);
+
+static struct iommu_group *get_pci_alias_group(struct pci_dev *pdev,
+					       unsigned long *devfns);
+
+/*
+ * To consider a PCI device isolated, we require ACS to support Source
+ * Validation, Request Redirection, Completer Redirection, and Upstream
+ * Forwarding.  This effectively means that devices cannot spoof their
+ * requester ID, requests and completions cannot be redirected, and all
+ * transactions are forwarded upstream, even as it passes through a
+ * bridge where the target device is downstream.
+ */
+#define REQ_ACS_FLAGS   (PCI_ACS_SV | PCI_ACS_RR | PCI_ACS_CR | PCI_ACS_UF)
+
+/*
+ * For multifunction devices which are not isolated from each other, find
+ * all the other non-isolated functions and look for existing groups.  For
+ * each function, we also need to look for aliases to or from other devices
+ * that may already have a group.
+ */
+static struct iommu_group *get_pci_function_alias_group(struct pci_dev *pdev,
+							unsigned long *devfns)
+{
+	struct pci_dev *tmp = NULL;
+	struct iommu_group *group;
+
+	if (!pdev->multifunction || pci_acs_enabled(pdev, REQ_ACS_FLAGS))
+		return NULL;
+
+	for_each_pci_dev(tmp) {
+		if (tmp == pdev || tmp->bus != pdev->bus ||
+		    PCI_SLOT(tmp->devfn) != PCI_SLOT(pdev->devfn) ||
+		    pci_acs_enabled(tmp, REQ_ACS_FLAGS))
+			continue;
+
+		group = get_pci_alias_group(tmp, devfns);
+		if (group) {
+			pci_dev_put(tmp);
+			return group;
+		}
+	}
+
+	return NULL;
+}
+
+/*
+ * Look for aliases to or from the given device for exisiting groups.  The
+ * dma_alias_devfn only supports aliases on the same bus, therefore the search
+ * space is quite small (especially since we're really only looking at pcie
+ * device, and therefore only expect multiple slots on the root complex or
+ * downstream switch ports).  It's conceivable though that a pair of
+ * multifunction devices could have aliases between them that would cause a
+ * loop.  To prevent this, we use a bitmap to track where we've been.
+ */
+static struct iommu_group *get_pci_alias_group(struct pci_dev *pdev,
+					       unsigned long *devfns)
+{
+	struct pci_dev *tmp = NULL;
+	struct iommu_group *group;
+
+	if (test_and_set_bit(pdev->devfn & 0xff, devfns))
+		return NULL;
+
+	group = iommu_group_get(&pdev->dev);
+	if (group)
+		return group;
+
+	for_each_pci_dev(tmp) {
+		if (tmp == pdev || tmp->bus != pdev->bus)
+			continue;
+
+		/* We alias them or they alias us */
+		if (((pdev->dev_flags & PCI_DEV_FLAGS_DMA_ALIAS_DEVFN) &&
+		     pdev->dma_alias_devfn == tmp->devfn) ||
+		    ((tmp->dev_flags & PCI_DEV_FLAGS_DMA_ALIAS_DEVFN) &&
+		     tmp->dma_alias_devfn == pdev->devfn)) {
+
+			group = get_pci_alias_group(tmp, devfns);
+			if (group) {
+				pci_dev_put(tmp);
+				return group;
+			}
+
+			group = get_pci_function_alias_group(tmp, devfns);
+			if (group) {
+				pci_dev_put(tmp);
+				return group;
+			}
+		}
+	}
+
+	return NULL;
+}
+
+struct group_for_pci_data {
+	struct pci_dev *pdev;
+	struct iommu_group *group;
+};
+
+/*
+ * DMA alias iterator callback, return the last seen device.  Stop and return
+ * the IOMMU group if we find one along the way.
+ */
+static int get_pci_alias_or_group(struct pci_dev *pdev, u16 alias, void *opaque)
+{
+	struct group_for_pci_data *data = opaque;
+
+	data->pdev = pdev;
+	data->group = iommu_group_get(&pdev->dev);
+
+	return data->group != NULL;
+}
+
+/*
+ * Use standard PCI bus topology, isolation features, and DMA alias quirks
+ * to find or create an IOMMU group for a device.
+ */
+static struct iommu_group *iommu_group_get_for_pci_dev(struct pci_dev *pdev)
+{
+	struct group_for_pci_data data;
+	struct pci_bus *bus;
+	struct iommu_group *group = NULL;
+	u64 devfns[4] = { 0 };
+
+	/*
+	 * Find the upstream DMA alias for the device.  A device must not
+	 * be aliased due to topology in order to have its own IOMMU group.
+	 * If we find an alias along the way that already belongs to a
+	 * group, use it.
+	 */
+	if (pci_for_each_dma_alias(pdev, get_pci_alias_or_group, &data))
+		return data.group;
+
+	pdev = data.pdev;
+
+	/*
+	 * Continue upstream from the point of minimum IOMMU granularity
+	 * due to aliases to the point where devices are protected from
+	 * peer-to-peer DMA by PCI ACS.  Again, if we find an existing
+	 * group, use it.
+	 */
+	for (bus = pdev->bus; !pci_is_root_bus(bus); bus = bus->parent) {
+		if (!bus->self)
+			continue;
+
+		if (pci_acs_path_enabled(bus->self, NULL, REQ_ACS_FLAGS))
+			break;
+
+		pdev = bus->self;
+
+		group = iommu_group_get(&pdev->dev);
+		if (group)
+			return group;
+	}
+
+	/*
+	 * Look for existing groups on device aliases.  If we alias another
+	 * device or another device aliases us, use the same group.
+	 */
+	group = get_pci_alias_group(pdev, (unsigned long *)devfns);
+	if (group)
+		return group;
+
+	/*
+	 * Look for existing groups on non-isolated functions on the same
+	 * slot and aliases of those funcions, if any.  No need to clear
+	 * the search bitmap, the tested devfns are still valid.
+	 */
+	group = get_pci_function_alias_group(pdev, (unsigned long *)devfns);
+	if (group)
+		return group;
+
+	/* No shared group found, allocate new */
+	return iommu_group_alloc();
+}
+
+/**
+ * iommu_group_get_for_dev - Find or create the IOMMU group for a device
+ * @dev: target device
+ *
+ * This function is intended to be called by IOMMU drivers and extended to
+ * support common, bus-defined algorithms when determining or creating the
+ * IOMMU group for a device.  On success, the caller will hold a reference
+ * to the returned IOMMU group, which will already include the provided
+ * device.  The reference should be released with iommu_group_put().
+ */
+struct iommu_group *iommu_group_get_for_dev(struct device *dev)
+{
+	struct iommu_group *group;
+	int ret;
+
+	group = iommu_group_get(dev);
+	if (group)
+		return group;
+
+	if (!dev_is_pci(dev))
+		return ERR_PTR(-EINVAL);
+
+	group = iommu_group_get_for_pci_dev(to_pci_dev(dev));
+
+	if (IS_ERR(group))
+		return group;
+
+	ret = iommu_group_add_device(group, dev);
+	if (ret) {
+		iommu_group_put(group);
+		return ERR_PTR(ret);
+	}
+
+	return group;
+}
+
+static int add_iommu_group(struct device *dev, void *data)
+{
+	struct iommu_callback_data *cb = data;
+	const struct iommu_ops *ops = cb->ops;
+
+	if (!ops->add_device)
+		return 0;
+
+	WARN_ON(dev->iommu_group);
+
+	ops->add_device(dev);
+
+	return 0;
+}
+
+static int iommu_bus_notifier(struct notifier_block *nb,
+			      unsigned long action, void *data)
+{
+	struct device *dev = data;
+	const struct iommu_ops *ops = dev->bus->iommu_ops;
+	struct iommu_group *group;
+	unsigned long group_action = 0;
+
+	/*
+	 * ADD/DEL call into iommu driver ops if provided, which may
+	 * result in ADD/DEL notifiers to group->notifier
+	 */
+	if (action == BUS_NOTIFY_ADD_DEVICE) {
+		if (ops->add_device)
+			return ops->add_device(dev);
+	} else if (action == BUS_NOTIFY_DEL_DEVICE) {
+		if (ops->remove_device && dev->iommu_group) {
+			ops->remove_device(dev);
+			return 0;
+		}
+	}
+
+	/*
+	 * Remaining BUS_NOTIFYs get filtered and republished to the
+	 * group, if anyone is listening
+	 */
+	group = iommu_group_get(dev);
+	if (!group)
+		return 0;
+
+	switch (action) {
+	case BUS_NOTIFY_BIND_DRIVER:
+		group_action = IOMMU_GROUP_NOTIFY_BIND_DRIVER;
+		break;
+	case BUS_NOTIFY_BOUND_DRIVER:
+		group_action = IOMMU_GROUP_NOTIFY_BOUND_DRIVER;
+		break;
+	case BUS_NOTIFY_UNBIND_DRIVER:
+		group_action = IOMMU_GROUP_NOTIFY_UNBIND_DRIVER;
+		break;
+	case BUS_NOTIFY_UNBOUND_DRIVER:
+		group_action = IOMMU_GROUP_NOTIFY_UNBOUND_DRIVER;
+		break;
+	}
+
+	if (group_action)
+		blocking_notifier_call_chain(&group->notifier,
+					     group_action, dev);
+
+	iommu_group_put(group);
+	return 0;
+}
+
+static int iommu_bus_init(struct bus_type *bus, const struct iommu_ops *ops)
+{
+	int err;
+	struct notifier_block *nb;
+	struct iommu_callback_data cb = {
+		.ops = ops,
+	};
+
+	nb = kzalloc(sizeof(struct notifier_block), GFP_KERNEL);
+	if (!nb)
+		return -ENOMEM;
+
+	nb->notifier_call = iommu_bus_notifier;
+
+	err = bus_register_notifier(bus, nb);
+	if (err) {
+		kfree(nb);
+		return err;
+	}
+
+	err = bus_for_each_dev(bus, NULL, &cb, add_iommu_group);
+	if (err) {
+		bus_unregister_notifier(bus, nb);
+		kfree(nb);
+		return err;
+	}
+
+	return 0;
+}
+
+/**
+ * bus_set_iommu - set iommu-callbacks for the bus
+ * @bus: bus.
+ * @ops: the callbacks provided by the iommu-driver
+ *
+ * This function is called by an iommu driver to set the iommu methods
+ * used for a particular bus. Drivers for devices on that bus can use
+ * the iommu-api after these ops are registered.
+ * This special function is needed because IOMMUs are usually devices on
+ * the bus itself, so the iommu drivers are not initialized when the bus
+ * is set up. With this function the iommu-driver can set the iommu-ops
+ * afterwards.
+ */
+int bus_set_iommu(struct bus_type *bus, const struct iommu_ops *ops)
+{
+	int err;
+
+	if (bus->iommu_ops != NULL)
+		return -EBUSY;
+
+	bus->iommu_ops = ops;
+
+	/* Do IOMMU specific setup for this bus-type */
+	err = iommu_bus_init(bus, ops);
+	if (err)
+		bus->iommu_ops = NULL;
+
+	return err;
+}
+EXPORT_SYMBOL_GPL(bus_set_iommu);
+
+bool iommu_present(struct bus_type *bus)
+{
+	return bus->iommu_ops != NULL;
+}
+EXPORT_SYMBOL_GPL(iommu_present);
+
+bool iommu_capable(struct bus_type *bus, enum iommu_cap cap)
+{
+	if (!bus->iommu_ops || !bus->iommu_ops->capable)
+		return false;
+
+	return bus->iommu_ops->capable(cap);
+}
+EXPORT_SYMBOL_GPL(iommu_capable);
+
+/**
+ * iommu_set_fault_handler() - set a fault handler for an iommu domain
+ * @domain: iommu domain
+ * @handler: fault handler
+ * @token: user data, will be passed back to the fault handler
+ *
+ * This function should be used by IOMMU users which want to be notified
+ * whenever an IOMMU fault happens.
+ *
+ * The fault handler itself should return 0 on success, and an appropriate
+ * error code otherwise.
+ */
+void iommu_set_fault_handler(struct iommu_domain *domain,
+					iommu_fault_handler_t handler,
+					void *token)
+{
+	BUG_ON(!domain);
+
+	domain->handler = handler;
+	domain->handler_token = token;
+}
+EXPORT_SYMBOL_GPL(iommu_set_fault_handler);
+
+struct iommu_domain *iommu_domain_alloc(struct bus_type *bus)
+{
+	struct iommu_domain *domain;
+
+	if (bus == NULL || bus->iommu_ops == NULL)
+		return NULL;
+
+	domain = bus->iommu_ops->domain_alloc(IOMMU_DOMAIN_UNMANAGED);
+	if (!domain)
+		return NULL;
+
+	domain->ops  = bus->iommu_ops;
+	domain->type = IOMMU_DOMAIN_UNMANAGED;
+
+	return domain;
+}
+EXPORT_SYMBOL_GPL(iommu_domain_alloc);
+
+void iommu_domain_free(struct iommu_domain *domain)
+{
+	domain->ops->domain_free(domain);
+}
+EXPORT_SYMBOL_GPL(iommu_domain_free);
+
+int iommu_attach_device(struct iommu_domain *domain, struct device *dev)
+{
+	int ret;
+	if (unlikely(domain->ops->attach_dev == NULL))
+		return -ENODEV;
+
+	ret = domain->ops->attach_dev(domain, dev);
+	if (!ret)
+		trace_attach_device_to_domain(dev);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(iommu_attach_device);
+
+void iommu_detach_device(struct iommu_domain *domain, struct device *dev)
+{
+	if (unlikely(domain->ops->detach_dev == NULL))
+		return;
+
+	domain->ops->detach_dev(domain, dev);
+	trace_detach_device_from_domain(dev);
+}
+EXPORT_SYMBOL_GPL(iommu_detach_device);
+
+/*
+ * IOMMU groups are really the natrual working unit of the IOMMU, but
+ * the IOMMU API works on domains and devices.  Bridge that gap by
+ * iterating over the devices in a group.  Ideally we'd have a single
+ * device which represents the requestor ID of the group, but we also
+ * allow IOMMU drivers to create policy defined minimum sets, where
+ * the physical hardware may be able to distiguish members, but we
+ * wish to group them at a higher level (ex. untrusted multi-function
+ * PCI devices).  Thus we attach each device.
+ */
+static int iommu_group_do_attach_device(struct device *dev, void *data)
+{
+	struct iommu_domain *domain = data;
+
+	return iommu_attach_device(domain, dev);
+}
+
+int iommu_attach_group(struct iommu_domain *domain, struct iommu_group *group)
+{
+	return iommu_group_for_each_dev(group, domain,
+					iommu_group_do_attach_device);
+}
+EXPORT_SYMBOL_GPL(iommu_attach_group);
+
+static int iommu_group_do_detach_device(struct device *dev, void *data)
+{
+	struct iommu_domain *domain = data;
+
+	iommu_detach_device(domain, dev);
+
+	return 0;
+}
+
+void iommu_detach_group(struct iommu_domain *domain, struct iommu_group *group)
+{
+	iommu_group_for_each_dev(group, domain, iommu_group_do_detach_device);
+}
+EXPORT_SYMBOL_GPL(iommu_detach_group);
+
+phys_addr_t iommu_iova_to_phys(struct iommu_domain *domain, dma_addr_t iova)
+{
+	if (unlikely(domain->ops->iova_to_phys == NULL))
+		return 0;
+
+	return domain->ops->iova_to_phys(domain, iova);
+}
+EXPORT_SYMBOL_GPL(iommu_iova_to_phys);
+
+static size_t iommu_pgsize(struct iommu_domain *domain,
+			   unsigned long addr_merge, size_t size)
+{
+	unsigned int pgsize_idx;
+	size_t pgsize;
+
+	/* Max page size that still fits into 'size' */
+	pgsize_idx = __fls(size);
+
+	/* need to consider alignment requirements ? */
+	if (likely(addr_merge)) {
+		/* Max page size allowed by address */
+		unsigned int align_pgsize_idx = __ffs(addr_merge);
+		pgsize_idx = min(pgsize_idx, align_pgsize_idx);
+	}
+
+	/* build a mask of acceptable page sizes */
+	pgsize = (1UL << (pgsize_idx + 1)) - 1;
+
+	/* throw away page sizes not supported by the hardware */
+	pgsize &= domain->ops->pgsize_bitmap;
+
+	/* make sure we're still sane */
+	BUG_ON(!pgsize);
+
+	/* pick the biggest page */
+	pgsize_idx = __fls(pgsize);
+	pgsize = 1UL << pgsize_idx;
+
+	return pgsize;
+}
+
+int iommu_map(struct iommu_domain *domain, unsigned long iova,
+	      phys_addr_t paddr, size_t size, int prot)
+{
+	unsigned long orig_iova = iova;
+	unsigned int min_pagesz;
+	size_t orig_size = size;
+	int ret = 0;
+
+	if (unlikely(domain->ops->map == NULL ||
+		     domain->ops->pgsize_bitmap == 0UL))
+		return -ENODEV;
+
+	if (unlikely(!(domain->type & __IOMMU_DOMAIN_PAGING)))
+		return -EINVAL;
+
+	/* find out the minimum page size supported */
+	min_pagesz = 1 << __ffs(domain->ops->pgsize_bitmap);
+
+	/*
+	 * both the virtual address and the physical one, as well as
+	 * the size of the mapping, must be aligned (at least) to the
+	 * size of the smallest page supported by the hardware
+	 */
+	if (!IS_ALIGNED(iova | paddr | size, min_pagesz)) {
+		pr_err("unaligned: iova 0x%lx pa %pa size 0x%zx min_pagesz 0x%x\n",
+		       iova, &paddr, size, min_pagesz);
+		return -EINVAL;
+	}
+
+	pr_debug("map: iova 0x%lx pa %pa size 0x%zx\n", iova, &paddr, size);
+
+	while (size) {
+		size_t pgsize = iommu_pgsize(domain, iova | paddr, size);
+
+		pr_debug("mapping: iova 0x%lx pa %pa pgsize 0x%zx\n",
+			 iova, &paddr, pgsize);
+
+		ret = domain->ops->map(domain, iova, paddr, pgsize, prot);
+		if (ret)
+			break;
+
+		iova += pgsize;
+		paddr += pgsize;
+		size -= pgsize;
+	}
+
+	/* unroll mapping in case something went wrong */
+	if (ret)
+		iommu_unmap(domain, orig_iova, orig_size - size);
+	else
+		trace_map(orig_iova, paddr, orig_size);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(iommu_map);
+
+size_t iommu_unmap(struct iommu_domain *domain, unsigned long iova, size_t size)
+{
+	size_t unmapped_page, unmapped = 0;
+	unsigned int min_pagesz;
+	unsigned long orig_iova = iova;
+
+	if (unlikely(domain->ops->unmap == NULL ||
+		     domain->ops->pgsize_bitmap == 0UL))
+		return -ENODEV;
+
+	if (unlikely(!(domain->type & __IOMMU_DOMAIN_PAGING)))
+		return -EINVAL;
+
+	/* find out the minimum page size supported */
+	min_pagesz = 1 << __ffs(domain->ops->pgsize_bitmap);
+
+	/*
+	 * The virtual address, as well as the size of the mapping, must be
+	 * aligned (at least) to the size of the smallest page supported
+	 * by the hardware
+	 */
+	if (!IS_ALIGNED(iova | size, min_pagesz)) {
+		pr_err("unaligned: iova 0x%lx size 0x%zx min_pagesz 0x%x\n",
+		       iova, size, min_pagesz);
+		return -EINVAL;
+	}
+
+	pr_debug("unmap this: iova 0x%lx size 0x%zx\n", iova, size);
+
+	/*
+	 * Keep iterating until we either unmap 'size' bytes (or more)
+	 * or we hit an area that isn't mapped.
+	 */
+	while (unmapped < size) {
+		size_t pgsize = iommu_pgsize(domain, iova, size - unmapped);
+
+		unmapped_page = domain->ops->unmap(domain, iova, pgsize);
+		if (!unmapped_page)
+			break;
+
+		pr_debug("unmapped: iova 0x%lx size 0x%zx\n",
+			 iova, unmapped_page);
+
+		iova += unmapped_page;
+		unmapped += unmapped_page;
+	}
+
+	trace_unmap(orig_iova, size, unmapped);
+	return unmapped;
+}
+EXPORT_SYMBOL_GPL(iommu_unmap);
+
+size_t default_iommu_map_sg(struct iommu_domain *domain, unsigned long iova,
+			 struct scatterlist *sg, unsigned int nents, int prot)
+{
+	struct scatterlist *s;
+	size_t mapped = 0;
+	unsigned int i, min_pagesz;
+	int ret;
+
+	if (unlikely(domain->ops->pgsize_bitmap == 0UL))
+		return 0;
+
+	min_pagesz = 1 << __ffs(domain->ops->pgsize_bitmap);
+
+	for_each_sg(sg, s, nents, i) {
+		phys_addr_t phys = page_to_phys(sg_page(s)) + s->offset;
+
+		/*
+		 * We are mapping on IOMMU page boundaries, so offset within
+		 * the page must be 0. However, the IOMMU may support pages
+		 * smaller than PAGE_SIZE, so s->offset may still represent
+		 * an offset of that boundary within the CPU page.
+		 */
+		if (!IS_ALIGNED(s->offset, min_pagesz))
+			goto out_err;
+
+		ret = iommu_map(domain, iova + mapped, phys, s->length, prot);
+		if (ret)
+			goto out_err;
+
+		mapped += s->length;
+	}
+
+	return mapped;
+
+out_err:
+	/* undo mappings already done */
+	iommu_unmap(domain, iova, mapped);
+
+	return 0;
+
+}
+EXPORT_SYMBOL_GPL(default_iommu_map_sg);
+
+int iommu_domain_window_enable(struct iommu_domain *domain, u32 wnd_nr,
+			       phys_addr_t paddr, u64 size, int prot)
+{
+	if (unlikely(domain->ops->domain_window_enable == NULL))
+		return -ENODEV;
+
+	return domain->ops->domain_window_enable(domain, wnd_nr, paddr, size,
+						 prot);
+}
+EXPORT_SYMBOL_GPL(iommu_domain_window_enable);
+
+void iommu_domain_window_disable(struct iommu_domain *domain, u32 wnd_nr)
+{
+	if (unlikely(domain->ops->domain_window_disable == NULL))
+		return;
+
+	return domain->ops->domain_window_disable(domain, wnd_nr);
+}
+EXPORT_SYMBOL_GPL(iommu_domain_window_disable);
+
+static int __init iommu_init(void)
+{
+	iommu_group_kset = kset_create_and_add("iommu_groups",
+					       NULL, kernel_kobj);
+	ida_init(&iommu_group_ida);
+	mutex_init(&iommu_group_mutex);
+
+	BUG_ON(!iommu_group_kset);
+
+	return 0;
+}
+arch_initcall(iommu_init);
+
+int iommu_domain_get_attr(struct iommu_domain *domain,
+			  enum iommu_attr attr, void *data)
+{
+	struct iommu_domain_geometry *geometry;
+	bool *paging;
+	int ret = 0;
+	u32 *count;
+
+	switch (attr) {
+	case DOMAIN_ATTR_GEOMETRY:
+		geometry  = data;
+		*geometry = domain->geometry;
+
+		break;
+	case DOMAIN_ATTR_PAGING:
+		paging  = data;
+		*paging = (domain->ops->pgsize_bitmap != 0UL);
+		break;
+	case DOMAIN_ATTR_WINDOWS:
+		count = data;
+
+		if (domain->ops->domain_get_windows != NULL)
+			*count = domain->ops->domain_get_windows(domain);
+		else
+			ret = -ENODEV;
+
+		break;
+	default:
+		if (!domain->ops->domain_get_attr)
+			return -EINVAL;
+
+		ret = domain->ops->domain_get_attr(domain, attr, data);
+	}
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(iommu_domain_get_attr);
+
+int iommu_domain_set_attr(struct iommu_domain *domain,
+			  enum iommu_attr attr, void *data)
+{
+	int ret = 0;
+	u32 *count;
+
+	switch (attr) {
+	case DOMAIN_ATTR_WINDOWS:
+		count = data;
+
+		if (domain->ops->domain_set_windows != NULL)
+			ret = domain->ops->domain_set_windows(domain, *count);
+		else
+			ret = -ENODEV;
+
+		break;
+	default:
+		if (domain->ops->domain_set_attr == NULL)
+			return -EINVAL;
+
+		ret = domain->ops->domain_set_attr(domain, attr, data);
+	}
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(iommu_domain_set_attr);