// SPDX-License-Identifier: GPL-2.0-only /* * Copyright (C) 2007-2008 Advanced Micro Devices, Inc. * Author: Joerg Roedel */ #define pr_fmt(fmt) "iommu: " fmt #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include static struct kset *iommu_group_kset; static DEFINE_IDA(iommu_group_ida); static unsigned int iommu_def_domain_type __read_mostly; static bool iommu_dma_strict __read_mostly = IS_ENABLED(CONFIG_IOMMU_DEFAULT_DMA_STRICT); static u32 iommu_cmd_line __read_mostly; struct iommu_group { struct kobject kobj; struct kobject *devices_kobj; struct list_head devices; struct mutex mutex; void *iommu_data; void (*iommu_data_release)(void *iommu_data); char *name; int id; struct iommu_domain *default_domain; struct iommu_domain *blocking_domain; struct iommu_domain *domain; struct list_head entry; unsigned int owner_cnt; void *owner; }; struct group_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); }; static const char * const iommu_group_resv_type_string[] = { [IOMMU_RESV_DIRECT] = "direct", [IOMMU_RESV_DIRECT_RELAXABLE] = "direct-relaxable", [IOMMU_RESV_RESERVED] = "reserved", [IOMMU_RESV_MSI] = "msi", [IOMMU_RESV_SW_MSI] = "msi", }; #define IOMMU_CMD_LINE_DMA_API BIT(0) #define IOMMU_CMD_LINE_STRICT BIT(1) static int iommu_bus_notifier(struct notifier_block *nb, unsigned long action, void *data); static int iommu_alloc_default_domain(struct iommu_group *group, struct device *dev); static struct iommu_domain *__iommu_domain_alloc(struct bus_type *bus, unsigned type); static int __iommu_attach_device(struct iommu_domain *domain, struct device *dev); static int __iommu_attach_group(struct iommu_domain *domain, struct iommu_group *group); static int __iommu_group_set_domain(struct iommu_group *group, struct iommu_domain *new_domain); static int iommu_create_device_direct_mappings(struct iommu_group *group, struct device *dev); static struct iommu_group *iommu_group_get_for_dev(struct device *dev); static ssize_t iommu_group_store_type(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 LIST_HEAD(iommu_device_list); static DEFINE_SPINLOCK(iommu_device_lock); static struct bus_type * const iommu_buses[] = { &platform_bus_type, #ifdef CONFIG_PCI &pci_bus_type, #endif #ifdef CONFIG_ARM_AMBA &amba_bustype, #endif #ifdef CONFIG_FSL_MC_BUS &fsl_mc_bus_type, #endif #ifdef CONFIG_TEGRA_HOST1X_CONTEXT_BUS &host1x_context_device_bus_type, #endif }; /* * Use a function instead of an array here because the domain-type is a * bit-field, so an array would waste memory. */ static const char *iommu_domain_type_str(unsigned int t) { switch (t) { case IOMMU_DOMAIN_BLOCKED: return "Blocked"; case IOMMU_DOMAIN_IDENTITY: return "Passthrough"; case IOMMU_DOMAIN_UNMANAGED: return "Unmanaged"; case IOMMU_DOMAIN_DMA: case IOMMU_DOMAIN_DMA_FQ: return "Translated"; default: return "Unknown"; } } static int __init iommu_subsys_init(void) { struct notifier_block *nb; if (!(iommu_cmd_line & IOMMU_CMD_LINE_DMA_API)) { if (IS_ENABLED(CONFIG_IOMMU_DEFAULT_PASSTHROUGH)) iommu_set_default_passthrough(false); else iommu_set_default_translated(false); if (iommu_default_passthrough() && cc_platform_has(CC_ATTR_MEM_ENCRYPT)) { pr_info("Memory encryption detected - Disabling default IOMMU Passthrough\n"); iommu_set_default_translated(false); } } if (!iommu_default_passthrough() && !iommu_dma_strict) iommu_def_domain_type = IOMMU_DOMAIN_DMA_FQ; pr_info("Default domain type: %s %s\n", iommu_domain_type_str(iommu_def_domain_type), (iommu_cmd_line & IOMMU_CMD_LINE_DMA_API) ? "(set via kernel command line)" : ""); if (!iommu_default_passthrough()) pr_info("DMA domain TLB invalidation policy: %s mode %s\n", iommu_dma_strict ? "strict" : "lazy", (iommu_cmd_line & IOMMU_CMD_LINE_STRICT) ? "(set via kernel command line)" : ""); nb = kcalloc(ARRAY_SIZE(iommu_buses), sizeof(*nb), GFP_KERNEL); if (!nb) return -ENOMEM; for (int i = 0; i < ARRAY_SIZE(iommu_buses); i++) { nb[i].notifier_call = iommu_bus_notifier; bus_register_notifier(iommu_buses[i], &nb[i]); } return 0; } subsys_initcall(iommu_subsys_init); /** * iommu_device_register() - Register an IOMMU hardware instance * @iommu: IOMMU handle for the instance * @ops: IOMMU ops to associate with the instance * @hwdev: (optional) actual instance device, used for fwnode lookup * * Return: 0 on success, or an error. */ int iommu_device_register(struct iommu_device *iommu, const struct iommu_ops *ops, struct device *hwdev) { /* We need to be able to take module references appropriately */ if (WARN_ON(is_module_address((unsigned long)ops) && !ops->owner)) return -EINVAL; iommu->ops = ops; if (hwdev) iommu->fwnode = dev_fwnode(hwdev); spin_lock(&iommu_device_lock); list_add_tail(&iommu->list, &iommu_device_list); spin_unlock(&iommu_device_lock); return 0; } EXPORT_SYMBOL_GPL(iommu_device_register); void iommu_device_unregister(struct iommu_device *iommu) { spin_lock(&iommu_device_lock); list_del(&iommu->list); spin_unlock(&iommu_device_lock); } EXPORT_SYMBOL_GPL(iommu_device_unregister); static struct dev_iommu *dev_iommu_get(struct device *dev) { struct dev_iommu *param = dev->iommu; if (param) return param; param = kzalloc(sizeof(*param), GFP_KERNEL); if (!param) return NULL; mutex_init(¶m->lock); dev->iommu = param; return param; } static void dev_iommu_free(struct device *dev) { struct dev_iommu *param = dev->iommu; dev->iommu = NULL; if (param->fwspec) { fwnode_handle_put(param->fwspec->iommu_fwnode); kfree(param->fwspec); } kfree(param); } static int __iommu_probe_device(struct device *dev, struct list_head *group_list) { const struct iommu_ops *ops = dev->bus->iommu_ops; struct iommu_device *iommu_dev; struct iommu_group *group; int ret; if (!ops) return -ENODEV; if (!dev_iommu_get(dev)) return -ENOMEM; if (!try_module_get(ops->owner)) { ret = -EINVAL; goto err_free; } iommu_dev = ops->probe_device(dev); if (IS_ERR(iommu_dev)) { ret = PTR_ERR(iommu_dev); goto out_module_put; } dev->iommu->iommu_dev = iommu_dev; group = iommu_group_get_for_dev(dev); if (IS_ERR(group)) { ret = PTR_ERR(group); goto out_release; } iommu_group_put(group); if (group_list && !group->default_domain && list_empty(&group->entry)) list_add_tail(&group->entry, group_list); iommu_device_link(iommu_dev, dev); return 0; out_release: if (ops->release_device) ops->release_device(dev); out_module_put: module_put(ops->owner); err_free: dev_iommu_free(dev); return ret; } int iommu_probe_device(struct device *dev) { const struct iommu_ops *ops; struct iommu_group *group; int ret; ret = __iommu_probe_device(dev, NULL); if (ret) goto err_out; group = iommu_group_get(dev); if (!group) { ret = -ENODEV; goto err_release; } /* * Try to allocate a default domain - needs support from the * IOMMU driver. There are still some drivers which don't * support default domains, so the return value is not yet * checked. */ mutex_lock(&group->mutex); iommu_alloc_default_domain(group, dev); /* * If device joined an existing group which has been claimed, don't * attach the default domain. */ if (group->default_domain && !group->owner) { ret = __iommu_attach_device(group->default_domain, dev); if (ret) { mutex_unlock(&group->mutex); iommu_group_put(group); goto err_release; } } iommu_create_device_direct_mappings(group, dev); mutex_unlock(&group->mutex); iommu_group_put(group); ops = dev_iommu_ops(dev); if (ops->probe_finalize) ops->probe_finalize(dev); return 0; err_release: iommu_release_device(dev); err_out: return ret; } void iommu_release_device(struct device *dev) { const struct iommu_ops *ops; if (!dev->iommu) return; iommu_device_unlink(dev->iommu->iommu_dev, dev); ops = dev_iommu_ops(dev); if (ops->release_device) ops->release_device(dev); iommu_group_remove_device(dev); module_put(ops->owner); dev_iommu_free(dev); } static int __init iommu_set_def_domain_type(char *str) { bool pt; int ret; ret = kstrtobool(str, &pt); if (ret) return ret; if (pt) iommu_set_default_passthrough(true); else iommu_set_default_translated(true); return 0; } early_param("iommu.passthrough", iommu_set_def_domain_type); static int __init iommu_dma_setup(char *str) { int ret = kstrtobool(str, &iommu_dma_strict); if (!ret) iommu_cmd_line |= IOMMU_CMD_LINE_STRICT; return ret; } early_param("iommu.strict", iommu_dma_setup); void iommu_set_dma_strict(void) { iommu_dma_strict = true; if (iommu_def_domain_type == IOMMU_DOMAIN_DMA_FQ) iommu_def_domain_type = IOMMU_DOMAIN_DMA; } 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); } /** * iommu_insert_resv_region - Insert a new region in the * list of reserved regions. * @new: new region to insert * @regions: list of regions * * Elements are sorted by start address and overlapping segments * of the same type are merged. */ static int iommu_insert_resv_region(struct iommu_resv_region *new, struct list_head *regions) { struct iommu_resv_region *iter, *tmp, *nr, *top; LIST_HEAD(stack); nr = iommu_alloc_resv_region(new->start, new->length, new->prot, new->type); if (!nr) return -ENOMEM; /* First add the new element based on start address sorting */ list_for_each_entry(iter, regions, list) { if (nr->start < iter->start || (nr->start == iter->start && nr->type <= iter->type)) break; } list_add_tail(&nr->list, &iter->list); /* Merge overlapping segments of type nr->type in @regions, if any */ list_for_each_entry_safe(iter, tmp, regions, list) { phys_addr_t top_end, iter_end = iter->start + iter->length - 1; /* no merge needed on elements of different types than @new */ if (iter->type != new->type) { list_move_tail(&iter->list, &stack); continue; } /* look for the last stack element of same type as @iter */ list_for_each_entry_reverse(top, &stack, list) if (top->type == iter->type) goto check_overlap; list_move_tail(&iter->list, &stack); continue; check_overlap: top_end = top->start + top->length - 1; if (iter->start > top_end + 1) { list_move_tail(&iter->list, &stack); } else { top->length = max(top_end, iter_end) - top->start + 1; list_del(&iter->list); kfree(iter); } } list_splice(&stack, regions); return 0; } static int iommu_insert_device_resv_regions(struct list_head *dev_resv_regions, struct list_head *group_resv_regions) { struct iommu_resv_region *entry; int ret = 0; list_for_each_entry(entry, dev_resv_regions, list) { ret = iommu_insert_resv_region(entry, group_resv_regions); if (ret) break; } return ret; } int iommu_get_group_resv_regions(struct iommu_group *group, struct list_head *head) { struct group_device *device; int ret = 0; mutex_lock(&group->mutex); list_for_each_entry(device, &group->devices, list) { struct list_head dev_resv_regions; /* * Non-API groups still expose reserved_regions in sysfs, * so filter out calls that get here that way. */ if (!device->dev->iommu) break; INIT_LIST_HEAD(&dev_resv_regions); iommu_get_resv_regions(device->dev, &dev_resv_regions); ret = iommu_insert_device_resv_regions(&dev_resv_regions, head); iommu_put_resv_regions(device->dev, &dev_resv_regions); if (ret) break; } mutex_unlock(&group->mutex); return ret; } EXPORT_SYMBOL_GPL(iommu_get_group_resv_regions); static ssize_t iommu_group_show_resv_regions(struct iommu_group *group, char *buf) { struct iommu_resv_region *region, *next; struct list_head group_resv_regions; char *str = buf; INIT_LIST_HEAD(&group_resv_regions); iommu_get_group_resv_regions(group, &group_resv_regions); list_for_each_entry_safe(region, next, &group_resv_regions, list) { str += sprintf(str, "0x%016llx 0x%016llx %s\n", (long long int)region->start, (long long int)(region->start + region->length - 1), iommu_group_resv_type_string[region->type]); kfree(region); } return (str - buf); } static ssize_t iommu_group_show_type(struct iommu_group *group, char *buf) { char *type = "unknown\n"; mutex_lock(&group->mutex); if (group->default_domain) { switch (group->default_domain->type) { case IOMMU_DOMAIN_BLOCKED: type = "blocked\n"; break; case IOMMU_DOMAIN_IDENTITY: type = "identity\n"; break; case IOMMU_DOMAIN_UNMANAGED: type = "unmanaged\n"; break; case IOMMU_DOMAIN_DMA: type = "DMA\n"; break; case IOMMU_DOMAIN_DMA_FQ: type = "DMA-FQ\n"; break; } } mutex_unlock(&group->mutex); strcpy(buf, type); return strlen(type); } static IOMMU_GROUP_ATTR(name, S_IRUGO, iommu_group_show_name, NULL); static IOMMU_GROUP_ATTR(reserved_regions, 0444, iommu_group_show_resv_regions, NULL); static IOMMU_GROUP_ATTR(type, 0644, iommu_group_show_type, iommu_group_store_type); static void iommu_group_release(struct kobject *kobj) { struct iommu_group *group = to_iommu_group(kobj); pr_debug("Releasing group %d\n", group->id); if (group->iommu_data_release) group->iommu_data_release(group->iommu_data); ida_free(&iommu_group_ida, group->id); if (group->default_domain) iommu_domain_free(group->default_domain); if (group->blocking_domain) iommu_domain_free(group->blocking_domain); 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 * * 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); INIT_LIST_HEAD(&group->entry); ret = ida_alloc(&iommu_group_ida, GFP_KERNEL); if (ret < 0) { kfree(group); return ERR_PTR(ret); } group->id = ret; ret = kobject_init_and_add(&group->kobj, &iommu_group_ktype, NULL, "%d", group->id); if (ret) { kobject_put(&group->kobj); 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); ret = iommu_group_create_file(group, &iommu_group_attr_reserved_regions); if (ret) return ERR_PTR(ret); ret = iommu_group_create_file(group, &iommu_group_attr_type); if (ret) return ERR_PTR(ret); pr_debug("Allocated group %d\n", group->id); 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); static int iommu_create_device_direct_mappings(struct iommu_group *group, struct device *dev) { struct iommu_domain *domain = group->default_domain; struct iommu_resv_region *entry; struct list_head mappings; unsigned long pg_size; int ret = 0; if (!domain || !iommu_is_dma_domain(domain)) return 0; BUG_ON(!domain->pgsize_bitmap); pg_size = 1UL << __ffs(domain->pgsize_bitmap); INIT_LIST_HEAD(&mappings); iommu_get_resv_regions(dev, &mappings); /* We need to consider overlapping regions for different devices */ list_for_each_entry(entry, &mappings, list) { dma_addr_t start, end, addr; size_t map_size = 0; start = ALIGN(entry->start, pg_size); end = ALIGN(entry->start + entry->length, pg_size); if (entry->type != IOMMU_RESV_DIRECT && entry->type != IOMMU_RESV_DIRECT_RELAXABLE) continue; for (addr = start; addr <= end; addr += pg_size) { phys_addr_t phys_addr; if (addr == end) goto map_end; phys_addr = iommu_iova_to_phys(domain, addr); if (!phys_addr) { map_size += pg_size; continue; } map_end: if (map_size) { ret = iommu_map(domain, addr - map_size, addr - map_size, map_size, entry->prot); if (ret) goto out; map_size = 0; } } } iommu_flush_iotlb_all(domain); out: iommu_put_resv_regions(dev, &mappings); return ret; } static bool iommu_is_attach_deferred(struct device *dev) { const struct iommu_ops *ops = dev_iommu_ops(dev); if (ops->is_attach_deferred) return ops->is_attach_deferred(dev); return false; } /** * 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 group_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) goto err_free_device; device->name = kasprintf(GFP_KERNEL, "%s", kobject_name(&dev->kobj)); rename: if (!device->name) { ret = -ENOMEM; goto err_remove_link; } ret = sysfs_create_link_nowarn(group->devices_kobj, &dev->kobj, device->name); if (ret) { if (ret == -EEXIST && i >= 0) { /* * Account for the slim chance of collision * and append an instance to the name. */ kfree(device->name); device->name = kasprintf(GFP_KERNEL, "%s.%d", kobject_name(&dev->kobj), i++); goto rename; } goto err_free_name; } kobject_get(group->devices_kobj); dev->iommu_group = group; mutex_lock(&group->mutex); list_add_tail(&device->list, &group->devices); if (group->domain && !iommu_is_attach_deferred(dev)) ret = __iommu_attach_device(group->domain, dev); mutex_unlock(&group->mutex); if (ret) goto err_put_group; trace_add_device_to_group(group->id, dev); dev_info(dev, "Adding to iommu group %d\n", group->id); return 0; err_put_group: mutex_lock(&group->mutex); list_del(&device->list); mutex_unlock(&group->mutex); dev->iommu_group = NULL; kobject_put(group->devices_kobj); sysfs_remove_link(group->devices_kobj, device->name); err_free_name: kfree(device->name); err_remove_link: sysfs_remove_link(&dev->kobj, "iommu_group"); err_free_device: kfree(device); dev_err(dev, "Failed to add to iommu group %d: %d\n", group->id, ret); return ret; } 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 group_device *tmp_device, *device = NULL; if (!group) return; dev_info(dev, "Removing from iommu group %d\n", group->id); 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); static int iommu_group_device_count(struct iommu_group *group) { struct group_device *entry; int ret = 0; list_for_each_entry(entry, &group->devices, list) ret++; return ret; } static int __iommu_group_for_each_dev(struct iommu_group *group, void *data, int (*fn)(struct device *, void *)) { struct group_device *device; int ret = 0; list_for_each_entry(device, &group->devices, list) { ret = fn(device->dev, data); if (ret) break; } return ret; } /** * 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 *)) { int ret; mutex_lock(&group->mutex); ret = __iommu_group_for_each_dev(group, data, fn); 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_ref_get - Increment reference on a group * @group: the group to use, must not be NULL * * This function is called by iommu drivers to take additional references on an * existing group. Returns the given group for convenience. */ struct iommu_group *iommu_group_ref_get(struct iommu_group *group) { kobject_get(group->devices_kobj); return group; } EXPORT_SYMBOL_GPL(iommu_group_ref_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_register_device_fault_handler() - Register a device fault handler * @dev: the device * @handler: the fault handler * @data: private data passed as argument to the handler * * When an IOMMU fault event is received, this handler gets called with the * fault event and data as argument. The handler should return 0 on success. If * the fault is recoverable (IOMMU_FAULT_PAGE_REQ), the consumer should also * complete the fault by calling iommu_page_response() with one of the following * response code: * - IOMMU_PAGE_RESP_SUCCESS: retry the translation * - IOMMU_PAGE_RESP_INVALID: terminate the fault * - IOMMU_PAGE_RESP_FAILURE: terminate the fault and stop reporting * page faults if possible. * * Return 0 if the fault handler was installed successfully, or an error. */ int iommu_register_device_fault_handler(struct device *dev, iommu_dev_fault_handler_t handler, void *data) { struct dev_iommu *param = dev->iommu; int ret = 0; if (!param) return -EINVAL; mutex_lock(¶m->lock); /* Only allow one fault handler registered for each device */ if (param->fault_param) { ret = -EBUSY; goto done_unlock; } get_device(dev); param->fault_param = kzalloc(sizeof(*param->fault_param), GFP_KERNEL); if (!param->fault_param) { put_device(dev); ret = -ENOMEM; goto done_unlock; } param->fault_param->handler = handler; param->fault_param->data = data; mutex_init(¶m->fault_param->lock); INIT_LIST_HEAD(¶m->fault_param->faults); done_unlock: mutex_unlock(¶m->lock); return ret; } EXPORT_SYMBOL_GPL(iommu_register_device_fault_handler); /** * iommu_unregister_device_fault_handler() - Unregister the device fault handler * @dev: the device * * Remove the device fault handler installed with * iommu_register_device_fault_handler(). * * Return 0 on success, or an error. */ int iommu_unregister_device_fault_handler(struct device *dev) { struct dev_iommu *param = dev->iommu; int ret = 0; if (!param) return -EINVAL; mutex_lock(¶m->lock); if (!param->fault_param) goto unlock; /* we cannot unregister handler if there are pending faults */ if (!list_empty(¶m->fault_param->faults)) { ret = -EBUSY; goto unlock; } kfree(param->fault_param); param->fault_param = NULL; put_device(dev); unlock: mutex_unlock(¶m->lock); return ret; } EXPORT_SYMBOL_GPL(iommu_unregister_device_fault_handler); /** * iommu_report_device_fault() - Report fault event to device driver * @dev: the device * @evt: fault event data * * Called by IOMMU drivers when a fault is detected, typically in a threaded IRQ * handler. When this function fails and the fault is recoverable, it is the * caller's responsibility to complete the fault. * * Return 0 on success, or an error. */ int iommu_report_device_fault(struct device *dev, struct iommu_fault_event *evt) { struct dev_iommu *param = dev->iommu; struct iommu_fault_event *evt_pending = NULL; struct iommu_fault_param *fparam; int ret = 0; if (!param || !evt) return -EINVAL; /* we only report device fault if there is a handler registered */ mutex_lock(¶m->lock); fparam = param->fault_param; if (!fparam || !fparam->handler) { ret = -EINVAL; goto done_unlock; } if (evt->fault.type == IOMMU_FAULT_PAGE_REQ && (evt->fault.prm.flags & IOMMU_FAULT_PAGE_REQUEST_LAST_PAGE)) { evt_pending = kmemdup(evt, sizeof(struct iommu_fault_event), GFP_KERNEL); if (!evt_pending) { ret = -ENOMEM; goto done_unlock; } mutex_lock(&fparam->lock); list_add_tail(&evt_pending->list, &fparam->faults); mutex_unlock(&fparam->lock); } ret = fparam->handler(&evt->fault, fparam->data); if (ret && evt_pending) { mutex_lock(&fparam->lock); list_del(&evt_pending->list); mutex_unlock(&fparam->lock); kfree(evt_pending); } done_unlock: mutex_unlock(¶m->lock); return ret; } EXPORT_SYMBOL_GPL(iommu_report_device_fault); int iommu_page_response(struct device *dev, struct iommu_page_response *msg) { bool needs_pasid; int ret = -EINVAL; struct iommu_fault_event *evt; struct iommu_fault_page_request *prm; struct dev_iommu *param = dev->iommu; const struct iommu_ops *ops = dev_iommu_ops(dev); bool has_pasid = msg->flags & IOMMU_PAGE_RESP_PASID_VALID; if (!ops->page_response) return -ENODEV; if (!param || !param->fault_param) return -EINVAL; if (msg->version != IOMMU_PAGE_RESP_VERSION_1 || msg->flags & ~IOMMU_PAGE_RESP_PASID_VALID) return -EINVAL; /* Only send response if there is a fault report pending */ mutex_lock(¶m->fault_param->lock); if (list_empty(¶m->fault_param->faults)) { dev_warn_ratelimited(dev, "no pending PRQ, drop response\n"); goto done_unlock; } /* * Check if we have a matching page request pending to respond, * otherwise return -EINVAL */ list_for_each_entry(evt, ¶m->fault_param->faults, list) { prm = &evt->fault.prm; if (prm->grpid != msg->grpid) continue; /* * If the PASID is required, the corresponding request is * matched using the group ID, the PASID valid bit and the PASID * value. Otherwise only the group ID matches request and * response. */ needs_pasid = prm->flags & IOMMU_FAULT_PAGE_RESPONSE_NEEDS_PASID; if (needs_pasid && (!has_pasid || msg->pasid != prm->pasid)) continue; if (!needs_pasid && has_pasid) { /* No big deal, just clear it. */ msg->flags &= ~IOMMU_PAGE_RESP_PASID_VALID; msg->pasid = 0; } ret = ops->page_response(dev, evt, msg); list_del(&evt->list); kfree(evt); break; } done_unlock: mutex_unlock(¶m->fault_param->lock); return ret; } EXPORT_SYMBOL_GPL(iommu_page_response); /** * 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 existing groups. DMA * aliases are only supported 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 (pci_devs_are_dma_aliases(pdev, tmp)) { 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; } /* * Generic device_group call-back function. It just allocates one * iommu-group per device. */ struct iommu_group *generic_device_group(struct device *dev) { return iommu_group_alloc(); } EXPORT_SYMBOL_GPL(generic_device_group); /* * Use standard PCI bus topology, isolation features, and DMA alias quirks * to find or create an IOMMU group for a device. */ struct iommu_group *pci_device_group(struct device *dev) { struct pci_dev *pdev = to_pci_dev(dev); struct group_for_pci_data data; struct pci_bus *bus; struct iommu_group *group = NULL; u64 devfns[4] = { 0 }; if (WARN_ON(!dev_is_pci(dev))) return ERR_PTR(-EINVAL); /* * 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(); } EXPORT_SYMBOL_GPL(pci_device_group); /* Get the IOMMU group for device on fsl-mc bus */ struct iommu_group *fsl_mc_device_group(struct device *dev) { struct device *cont_dev = fsl_mc_cont_dev(dev); struct iommu_group *group; group = iommu_group_get(cont_dev); if (!group) group = iommu_group_alloc(); return group; } EXPORT_SYMBOL_GPL(fsl_mc_device_group); static int iommu_get_def_domain_type(struct device *dev) { const struct iommu_ops *ops = dev_iommu_ops(dev); if (dev_is_pci(dev) && to_pci_dev(dev)->untrusted) return IOMMU_DOMAIN_DMA; if (ops->def_domain_type) return ops->def_domain_type(dev); return 0; } static int iommu_group_alloc_default_domain(struct bus_type *bus, struct iommu_group *group, unsigned int type) { struct iommu_domain *dom; dom = __iommu_domain_alloc(bus, type); if (!dom && type != IOMMU_DOMAIN_DMA) { dom = __iommu_domain_alloc(bus, IOMMU_DOMAIN_DMA); if (dom) pr_warn("Failed to allocate default IOMMU domain of type %u for group %s - Falling back to IOMMU_DOMAIN_DMA", type, group->name); } if (!dom) return -ENOMEM; group->default_domain = dom; if (!group->domain) group->domain = dom; return 0; } static int iommu_alloc_default_domain(struct iommu_group *group, struct device *dev) { unsigned int type; if (group->default_domain) return 0; type = iommu_get_def_domain_type(dev) ? : iommu_def_domain_type; return iommu_group_alloc_default_domain(dev->bus, group, type); } /** * 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(). */ static struct iommu_group *iommu_group_get_for_dev(struct device *dev) { const struct iommu_ops *ops = dev_iommu_ops(dev); struct iommu_group *group; int ret; group = iommu_group_get(dev); if (group) return group; group = ops->device_group(dev); if (WARN_ON_ONCE(group == NULL)) return ERR_PTR(-EINVAL); if (IS_ERR(group)) return group; ret = iommu_group_add_device(group, dev); if (ret) goto out_put_group; return group; out_put_group: iommu_group_put(group); return ERR_PTR(ret); } struct iommu_domain *iommu_group_default_domain(struct iommu_group *group) { return group->default_domain; } static int probe_iommu_group(struct device *dev, void *data) { struct list_head *group_list = data; struct iommu_group *group; int ret; /* Device is probed already if in a group */ group = iommu_group_get(dev); if (group) { iommu_group_put(group); return 0; } ret = __iommu_probe_device(dev, group_list); if (ret == -ENODEV) ret = 0; return ret; } static int remove_iommu_group(struct device *dev, void *data) { iommu_release_device(dev); return 0; } static int iommu_bus_notifier(struct notifier_block *nb, unsigned long action, void *data) { struct device *dev = data; if (action == BUS_NOTIFY_ADD_DEVICE) { int ret; ret = iommu_probe_device(dev); return (ret) ? NOTIFY_DONE : NOTIFY_OK; } else if (action == BUS_NOTIFY_REMOVED_DEVICE) { iommu_release_device(dev); return NOTIFY_OK; } return 0; } struct __group_domain_type { struct device *dev; unsigned int type; }; static int probe_get_default_domain_type(struct device *dev, void *data) { struct __group_domain_type *gtype = data; unsigned int type = iommu_get_def_domain_type(dev); if (type) { if (gtype->type && gtype->type != type) { dev_warn(dev, "Device needs domain type %s, but device %s in the same iommu group requires type %s - using default\n", iommu_domain_type_str(type), dev_name(gtype->dev), iommu_domain_type_str(gtype->type)); gtype->type = 0; } if (!gtype->dev) { gtype->dev = dev; gtype->type = type; } } return 0; } static void probe_alloc_default_domain(struct bus_type *bus, struct iommu_group *group) { struct __group_domain_type gtype; memset(>ype, 0, sizeof(gtype)); /* Ask for default domain requirements of all devices in the group */ __iommu_group_for_each_dev(group, >ype, probe_get_default_domain_type); if (!gtype.type) gtype.type = iommu_def_domain_type; iommu_group_alloc_default_domain(bus, group, gtype.type); } static int iommu_group_do_dma_attach(struct device *dev, void *data) { struct iommu_domain *domain = data; int ret = 0; if (!iommu_is_attach_deferred(dev)) ret = __iommu_attach_device(domain, dev); return ret; } static int __iommu_group_dma_attach(struct iommu_group *group) { return __iommu_group_for_each_dev(group, group->default_domain, iommu_group_do_dma_attach); } static int iommu_group_do_probe_finalize(struct device *dev, void *data) { const struct iommu_ops *ops = dev_iommu_ops(dev); if (ops->probe_finalize) ops->probe_finalize(dev); return 0; } static void __iommu_group_dma_finalize(struct iommu_group *group) { __iommu_group_for_each_dev(group, group->default_domain, iommu_group_do_probe_finalize); } static int iommu_do_create_direct_mappings(struct device *dev, void *data) { struct iommu_group *group = data; iommu_create_device_direct_mappings(group, dev); return 0; } static int iommu_group_create_direct_mappings(struct iommu_group *group) { return __iommu_group_for_each_dev(group, group, iommu_do_create_direct_mappings); } int bus_iommu_probe(struct bus_type *bus) { struct iommu_group *group, *next; LIST_HEAD(group_list); int ret; /* * This code-path does not allocate the default domain when * creating the iommu group, so do it after the groups are * created. */ ret = bus_for_each_dev(bus, NULL, &group_list, probe_iommu_group); if (ret) return ret; list_for_each_entry_safe(group, next, &group_list, entry) { /* Remove item from the list */ list_del_init(&group->entry); mutex_lock(&group->mutex); /* Try to allocate default domain */ probe_alloc_default_domain(bus, group); if (!group->default_domain) { mutex_unlock(&group->mutex); continue; } iommu_group_create_direct_mappings(group); ret = __iommu_group_dma_attach(group); mutex_unlock(&group->mutex); if (ret) break; __iommu_group_dma_finalize(group); } return ret; } /** * 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 (ops == NULL) { bus->iommu_ops = NULL; return 0; } if (bus->iommu_ops != NULL) return -EBUSY; bus->iommu_ops = ops; /* Do IOMMU specific setup for this bus-type */ err = bus_iommu_probe(bus); if (err) { /* Clean up */ bus_for_each_dev(bus, NULL, NULL, remove_iommu_group); 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); /** * device_iommu_capable() - check for a general IOMMU capability * @dev: device to which the capability would be relevant, if available * @cap: IOMMU capability * * Return: true if an IOMMU is present and supports the given capability * for the given device, otherwise false. */ bool device_iommu_capable(struct device *dev, enum iommu_cap cap) { const struct iommu_ops *ops; if (!dev->iommu || !dev->iommu->iommu_dev) return false; ops = dev_iommu_ops(dev); if (!ops->capable) return false; return ops->capable(dev, cap); } EXPORT_SYMBOL_GPL(device_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); static struct iommu_domain *__iommu_domain_alloc(struct bus_type *bus, unsigned type) { struct iommu_domain *domain; if (bus == NULL || bus->iommu_ops == NULL) return NULL; domain = bus->iommu_ops->domain_alloc(type); if (!domain) return NULL; domain->type = type; /* Assume all sizes by default; the driver may override this later */ domain->pgsize_bitmap = bus->iommu_ops->pgsize_bitmap; if (!domain->ops) domain->ops = bus->iommu_ops->default_domain_ops; if (iommu_is_dma_domain(domain) && iommu_get_dma_cookie(domain)) { iommu_domain_free(domain); domain = NULL; } return domain; } struct iommu_domain *iommu_domain_alloc(struct bus_type *bus) { return __iommu_domain_alloc(bus, IOMMU_DOMAIN_UNMANAGED); } EXPORT_SYMBOL_GPL(iommu_domain_alloc); void iommu_domain_free(struct iommu_domain *domain) { iommu_put_dma_cookie(domain); domain->ops->free(domain); } EXPORT_SYMBOL_GPL(iommu_domain_free); /* * Put the group's domain back to the appropriate core-owned domain - either the * standard kernel-mode DMA configuration or an all-DMA-blocked domain. */ static void __iommu_group_set_core_domain(struct iommu_group *group) { struct iommu_domain *new_domain; int ret; if (group->owner) new_domain = group->blocking_domain; else new_domain = group->default_domain; ret = __iommu_group_set_domain(group, new_domain); WARN(ret, "iommu driver failed to attach the default/blocking domain"); } static 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; } int iommu_attach_device(struct iommu_domain *domain, struct device *dev) { struct iommu_group *group; int ret; group = iommu_group_get(dev); if (!group) return -ENODEV; /* * Lock the group to make sure the device-count doesn't * change while we are attaching */ mutex_lock(&group->mutex); ret = -EINVAL; if (iommu_group_device_count(group) != 1) goto out_unlock; ret = __iommu_attach_group(domain, group); out_unlock: mutex_unlock(&group->mutex); iommu_group_put(group); return ret; } EXPORT_SYMBOL_GPL(iommu_attach_device); int iommu_deferred_attach(struct device *dev, struct iommu_domain *domain) { if (iommu_is_attach_deferred(dev)) return __iommu_attach_device(domain, dev); return 0; } static void __iommu_detach_device(struct iommu_domain *domain, struct device *dev) { if (iommu_is_attach_deferred(dev)) return; domain->ops->detach_dev(domain, dev); trace_detach_device_from_domain(dev); } void iommu_detach_device(struct iommu_domain *domain, struct device *dev) { struct iommu_group *group; group = iommu_group_get(dev); if (!group) return; mutex_lock(&group->mutex); if (WARN_ON(domain != group->domain) || WARN_ON(iommu_group_device_count(group) != 1)) goto out_unlock; __iommu_group_set_core_domain(group); out_unlock: mutex_unlock(&group->mutex); iommu_group_put(group); } EXPORT_SYMBOL_GPL(iommu_detach_device); struct iommu_domain *iommu_get_domain_for_dev(struct device *dev) { struct iommu_domain *domain; struct iommu_group *group; group = iommu_group_get(dev); if (!group) return NULL; domain = group->domain; iommu_group_put(group); return domain; } EXPORT_SYMBOL_GPL(iommu_get_domain_for_dev); /* * For IOMMU_DOMAIN_DMA implementations which already provide their own * guarantees that the group and its default domain are valid and correct. */ struct iommu_domain *iommu_get_dma_domain(struct device *dev) { return dev->iommu_group->default_domain; } /* * IOMMU groups are really the natural 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); } static int __iommu_attach_group(struct iommu_domain *domain, struct iommu_group *group) { int ret; if (group->domain && group->domain != group->default_domain && group->domain != group->blocking_domain) return -EBUSY; ret = __iommu_group_for_each_dev(group, domain, iommu_group_do_attach_device); if (ret == 0) group->domain = domain; return ret; } int iommu_attach_group(struct iommu_domain *domain, struct iommu_group *group) { int ret; mutex_lock(&group->mutex); ret = __iommu_attach_group(domain, group); mutex_unlock(&group->mutex); return ret; } 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; } static int __iommu_group_set_domain(struct iommu_group *group, struct iommu_domain *new_domain) { int ret; if (group->domain == new_domain) return 0; /* * New drivers should support default domains and so the detach_dev() op * will never be called. Otherwise the NULL domain represents some * platform specific behavior. */ if (!new_domain) { if (WARN_ON(!group->domain->ops->detach_dev)) return -EINVAL; __iommu_group_for_each_dev(group, group->domain, iommu_group_do_detach_device); group->domain = NULL; return 0; } /* * Changing the domain is done by calling attach_dev() on the new * domain. This switch does not have to be atomic and DMA can be * discarded during the transition. DMA must only be able to access * either new_domain or group->domain, never something else. * * Note that this is called in error unwind paths, attaching to a * domain that has already been attached cannot fail. */ ret = __iommu_group_for_each_dev(group, new_domain, iommu_group_do_attach_device); if (ret) return ret; group->domain = new_domain; return 0; } void iommu_detach_group(struct iommu_domain *domain, struct iommu_group *group) { mutex_lock(&group->mutex); __iommu_group_set_core_domain(group); mutex_unlock(&group->mutex); } EXPORT_SYMBOL_GPL(iommu_detach_group); phys_addr_t iommu_iova_to_phys(struct iommu_domain *domain, dma_addr_t iova) { if (domain->type == IOMMU_DOMAIN_IDENTITY) return iova; if (domain->type == IOMMU_DOMAIN_BLOCKED) 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 iova, phys_addr_t paddr, size_t size, size_t *count) { unsigned int pgsize_idx, pgsize_idx_next; unsigned long pgsizes; size_t offset, pgsize, pgsize_next; unsigned long addr_merge = paddr | iova; /* Page sizes supported by the hardware and small enough for @size */ pgsizes = domain->pgsize_bitmap & GENMASK(__fls(size), 0); /* Constrain the page sizes further based on the maximum alignment */ if (likely(addr_merge)) pgsizes &= GENMASK(__ffs(addr_merge), 0); /* Make sure we have at least one suitable page size */ BUG_ON(!pgsizes); /* Pick the biggest page size remaining */ pgsize_idx = __fls(pgsizes); pgsize = BIT(pgsize_idx); if (!count) return pgsize; /* Find the next biggest support page size, if it exists */ pgsizes = domain->pgsize_bitmap & ~GENMASK(pgsize_idx, 0); if (!pgsizes) goto out_set_count; pgsize_idx_next = __ffs(pgsizes); pgsize_next = BIT(pgsize_idx_next); /* * There's no point trying a bigger page size unless the virtual * and physical addresses are similarly offset within the larger page. */ if ((iova ^ paddr) & (pgsize_next - 1)) goto out_set_count; /* Calculate the offset to the next page size alignment boundary */ offset = pgsize_next - (addr_merge & (pgsize_next - 1)); /* * If size is big enough to accommodate the larger page, reduce * the number of smaller pages. */ if (offset + pgsize_next <= size) size = offset; out_set_count: *count = size >> pgsize_idx; return pgsize; } static int __iommu_map_pages(struct iommu_domain *domain, unsigned long iova, phys_addr_t paddr, size_t size, int prot, gfp_t gfp, size_t *mapped) { const struct iommu_domain_ops *ops = domain->ops; size_t pgsize, count; int ret; pgsize = iommu_pgsize(domain, iova, paddr, size, &count); pr_debug("mapping: iova 0x%lx pa %pa pgsize 0x%zx count %zu\n", iova, &paddr, pgsize, count); if (ops->map_pages) { ret = ops->map_pages(domain, iova, paddr, pgsize, count, prot, gfp, mapped); } else { ret = ops->map(domain, iova, paddr, pgsize, prot, gfp); *mapped = ret ? 0 : pgsize; } return ret; } static int __iommu_map(struct iommu_domain *domain, unsigned long iova, phys_addr_t paddr, size_t size, int prot, gfp_t gfp) { const struct iommu_domain_ops *ops = domain->ops; unsigned long orig_iova = iova; unsigned int min_pagesz; size_t orig_size = size; phys_addr_t orig_paddr = paddr; int ret = 0; if (unlikely(!(ops->map || ops->map_pages) || domain->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->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 mapped = 0; ret = __iommu_map_pages(domain, iova, paddr, size, prot, gfp, &mapped); /* * Some pages may have been mapped, even if an error occurred, * so we should account for those so they can be unmapped. */ size -= mapped; if (ret) break; iova += mapped; paddr += mapped; } /* unroll mapping in case something went wrong */ if (ret) iommu_unmap(domain, orig_iova, orig_size - size); else trace_map(orig_iova, orig_paddr, orig_size); return ret; } static int _iommu_map(struct iommu_domain *domain, unsigned long iova, phys_addr_t paddr, size_t size, int prot, gfp_t gfp) { const struct iommu_domain_ops *ops = domain->ops; int ret; ret = __iommu_map(domain, iova, paddr, size, prot, gfp); if (ret == 0 && ops->iotlb_sync_map) ops->iotlb_sync_map(domain, iova, size); return ret; } int iommu_map(struct iommu_domain *domain, unsigned long iova, phys_addr_t paddr, size_t size, int prot) { might_sleep(); return _iommu_map(domain, iova, paddr, size, prot, GFP_KERNEL); } EXPORT_SYMBOL_GPL(iommu_map); int iommu_map_atomic(struct iommu_domain *domain, unsigned long iova, phys_addr_t paddr, size_t size, int prot) { return _iommu_map(domain, iova, paddr, size, prot, GFP_ATOMIC); } EXPORT_SYMBOL_GPL(iommu_map_atomic); static size_t __iommu_unmap_pages(struct iommu_domain *domain, unsigned long iova, size_t size, struct iommu_iotlb_gather *iotlb_gather) { const struct iommu_domain_ops *ops = domain->ops; size_t pgsize, count; pgsize = iommu_pgsize(domain, iova, iova, size, &count); return ops->unmap_pages ? ops->unmap_pages(domain, iova, pgsize, count, iotlb_gather) : ops->unmap(domain, iova, pgsize, iotlb_gather); } static size_t __iommu_unmap(struct iommu_domain *domain, unsigned long iova, size_t size, struct iommu_iotlb_gather *iotlb_gather) { const struct iommu_domain_ops *ops = domain->ops; size_t unmapped_page, unmapped = 0; unsigned long orig_iova = iova; unsigned int min_pagesz; if (unlikely(!(ops->unmap || ops->unmap_pages) || domain->pgsize_bitmap == 0UL)) return 0; if (unlikely(!(domain->type & __IOMMU_DOMAIN_PAGING))) return 0; /* find out the minimum page size supported */ min_pagesz = 1 << __ffs(domain->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 0; } 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) { unmapped_page = __iommu_unmap_pages(domain, iova, size - unmapped, iotlb_gather); 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; } size_t iommu_unmap(struct iommu_domain *domain, unsigned long iova, size_t size) { struct iommu_iotlb_gather iotlb_gather; size_t ret; iommu_iotlb_gather_init(&iotlb_gather); ret = __iommu_unmap(domain, iova, size, &iotlb_gather); iommu_iotlb_sync(domain, &iotlb_gather); return ret; } EXPORT_SYMBOL_GPL(iommu_unmap); size_t iommu_unmap_fast(struct iommu_domain *domain, unsigned long iova, size_t size, struct iommu_iotlb_gather *iotlb_gather) { return __iommu_unmap(domain, iova, size, iotlb_gather); } EXPORT_SYMBOL_GPL(iommu_unmap_fast); static ssize_t __iommu_map_sg(struct iommu_domain *domain, unsigned long iova, struct scatterlist *sg, unsigned int nents, int prot, gfp_t gfp) { const struct iommu_domain_ops *ops = domain->ops; size_t len = 0, mapped = 0; phys_addr_t start; unsigned int i = 0; int ret; while (i <= nents) { phys_addr_t s_phys = sg_phys(sg); if (len && s_phys != start + len) { ret = __iommu_map(domain, iova + mapped, start, len, prot, gfp); if (ret) goto out_err; mapped += len; len = 0; } if (sg_is_dma_bus_address(sg)) goto next; if (len) { len += sg->length; } else { len = sg->length; start = s_phys; } next: if (++i < nents) sg = sg_next(sg); } if (ops->iotlb_sync_map) ops->iotlb_sync_map(domain, iova, mapped); return mapped; out_err: /* undo mappings already done */ iommu_unmap(domain, iova, mapped); return ret; } ssize_t iommu_map_sg(struct iommu_domain *domain, unsigned long iova, struct scatterlist *sg, unsigned int nents, int prot) { might_sleep(); return __iommu_map_sg(domain, iova, sg, nents, prot, GFP_KERNEL); } EXPORT_SYMBOL_GPL(iommu_map_sg); ssize_t iommu_map_sg_atomic(struct iommu_domain *domain, unsigned long iova, struct scatterlist *sg, unsigned int nents, int prot) { return __iommu_map_sg(domain, iova, sg, nents, prot, GFP_ATOMIC); } /** * report_iommu_fault() - report about an IOMMU fault to the IOMMU framework * @domain: the iommu domain where the fault has happened * @dev: the device where the fault has happened * @iova: the faulting address * @flags: mmu fault flags (e.g. IOMMU_FAULT_READ/IOMMU_FAULT_WRITE/...) * * This function should be called by the low-level IOMMU implementations * whenever IOMMU faults happen, to allow high-level users, that are * interested in such events, to know about them. * * This event may be useful for several possible use cases: * - mere logging of the event * - dynamic TLB/PTE loading * - if restarting of the faulting device is required * * Returns 0 on success and an appropriate error code otherwise (if dynamic * PTE/TLB loading will one day be supported, implementations will be able * to tell whether it succeeded or not according to this return value). * * Specifically, -ENOSYS is returned if a fault handler isn't installed * (though fault handlers can also return -ENOSYS, in case they want to * elicit the default behavior of the IOMMU drivers). */ int report_iommu_fault(struct iommu_domain *domain, struct device *dev, unsigned long iova, int flags) { int ret = -ENOSYS; /* * if upper layers showed interest and installed a fault handler, * invoke it. */ if (domain->handler) ret = domain->handler(domain, dev, iova, flags, domain->handler_token); trace_io_page_fault(dev, iova, flags); return ret; } EXPORT_SYMBOL_GPL(report_iommu_fault); static int __init iommu_init(void) { iommu_group_kset = kset_create_and_add("iommu_groups", NULL, kernel_kobj); BUG_ON(!iommu_group_kset); iommu_debugfs_setup(); return 0; } core_initcall(iommu_init); int iommu_enable_nesting(struct iommu_domain *domain) { if (domain->type != IOMMU_DOMAIN_UNMANAGED) return -EINVAL; if (!domain->ops->enable_nesting) return -EINVAL; return domain->ops->enable_nesting(domain); } EXPORT_SYMBOL_GPL(iommu_enable_nesting); int iommu_set_pgtable_quirks(struct iommu_domain *domain, unsigned long quirk) { if (domain->type != IOMMU_DOMAIN_UNMANAGED) return -EINVAL; if (!domain->ops->set_pgtable_quirks) return -EINVAL; return domain->ops->set_pgtable_quirks(domain, quirk); } EXPORT_SYMBOL_GPL(iommu_set_pgtable_quirks); void iommu_get_resv_regions(struct device *dev, struct list_head *list) { const struct iommu_ops *ops = dev_iommu_ops(dev); if (ops->get_resv_regions) ops->get_resv_regions(dev, list); } /** * iommu_put_resv_regions - release resered regions * @dev: device for which to free reserved regions * @list: reserved region list for device * * This releases a reserved region list acquired by iommu_get_resv_regions(). */ void iommu_put_resv_regions(struct device *dev, struct list_head *list) { struct iommu_resv_region *entry, *next; list_for_each_entry_safe(entry, next, list, list) { if (entry->free) entry->free(dev, entry); else kfree(entry); } } EXPORT_SYMBOL(iommu_put_resv_regions); struct iommu_resv_region *iommu_alloc_resv_region(phys_addr_t start, size_t length, int prot, enum iommu_resv_type type) { struct iommu_resv_region *region; region = kzalloc(sizeof(*region), GFP_KERNEL); if (!region) return NULL; INIT_LIST_HEAD(®ion->list); region->start = start; region->length = length; region->prot = prot; region->type = type; return region; } EXPORT_SYMBOL_GPL(iommu_alloc_resv_region); void iommu_set_default_passthrough(bool cmd_line) { if (cmd_line) iommu_cmd_line |= IOMMU_CMD_LINE_DMA_API; iommu_def_domain_type = IOMMU_DOMAIN_IDENTITY; } void iommu_set_default_translated(bool cmd_line) { if (cmd_line) iommu_cmd_line |= IOMMU_CMD_LINE_DMA_API; iommu_def_domain_type = IOMMU_DOMAIN_DMA; } bool iommu_default_passthrough(void) { return iommu_def_domain_type == IOMMU_DOMAIN_IDENTITY; } EXPORT_SYMBOL_GPL(iommu_default_passthrough); const struct iommu_ops *iommu_ops_from_fwnode(struct fwnode_handle *fwnode) { const struct iommu_ops *ops = NULL; struct iommu_device *iommu; spin_lock(&iommu_device_lock); list_for_each_entry(iommu, &iommu_device_list, list) if (iommu->fwnode == fwnode) { ops = iommu->ops; break; } spin_unlock(&iommu_device_lock); return ops; } int iommu_fwspec_init(struct device *dev, struct fwnode_handle *iommu_fwnode, const struct iommu_ops *ops) { struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev); if (fwspec) return ops == fwspec->ops ? 0 : -EINVAL; if (!dev_iommu_get(dev)) return -ENOMEM; /* Preallocate for the overwhelmingly common case of 1 ID */ fwspec = kzalloc(struct_size(fwspec, ids, 1), GFP_KERNEL); if (!fwspec) return -ENOMEM; of_node_get(to_of_node(iommu_fwnode)); fwspec->iommu_fwnode = iommu_fwnode; fwspec->ops = ops; dev_iommu_fwspec_set(dev, fwspec); return 0; } EXPORT_SYMBOL_GPL(iommu_fwspec_init); void iommu_fwspec_free(struct device *dev) { struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev); if (fwspec) { fwnode_handle_put(fwspec->iommu_fwnode); kfree(fwspec); dev_iommu_fwspec_set(dev, NULL); } } EXPORT_SYMBOL_GPL(iommu_fwspec_free); int iommu_fwspec_add_ids(struct device *dev, u32 *ids, int num_ids) { struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev); int i, new_num; if (!fwspec) return -EINVAL; new_num = fwspec->num_ids + num_ids; if (new_num > 1) { fwspec = krealloc(fwspec, struct_size(fwspec, ids, new_num), GFP_KERNEL); if (!fwspec) return -ENOMEM; dev_iommu_fwspec_set(dev, fwspec); } for (i = 0; i < num_ids; i++) fwspec->ids[fwspec->num_ids + i] = ids[i]; fwspec->num_ids = new_num; return 0; } EXPORT_SYMBOL_GPL(iommu_fwspec_add_ids); /* * Per device IOMMU features. */ int iommu_dev_enable_feature(struct device *dev, enum iommu_dev_features feat) { if (dev->iommu && dev->iommu->iommu_dev) { const struct iommu_ops *ops = dev->iommu->iommu_dev->ops; if (ops->dev_enable_feat) return ops->dev_enable_feat(dev, feat); } return -ENODEV; } EXPORT_SYMBOL_GPL(iommu_dev_enable_feature); /* * The device drivers should do the necessary cleanups before calling this. */ int iommu_dev_disable_feature(struct device *dev, enum iommu_dev_features feat) { if (dev->iommu && dev->iommu->iommu_dev) { const struct iommu_ops *ops = dev->iommu->iommu_dev->ops; if (ops->dev_disable_feat) return ops->dev_disable_feat(dev, feat); } return -EBUSY; } EXPORT_SYMBOL_GPL(iommu_dev_disable_feature); /** * iommu_sva_bind_device() - Bind a process address space to a device * @dev: the device * @mm: the mm to bind, caller must hold a reference to it * @drvdata: opaque data pointer to pass to bind callback * * Create a bond between device and address space, allowing the device to access * the mm using the returned PASID. If a bond already exists between @device and * @mm, it is returned and an additional reference is taken. Caller must call * iommu_sva_unbind_device() to release each reference. * * iommu_dev_enable_feature(dev, IOMMU_DEV_FEAT_SVA) must be called first, to * initialize the required SVA features. * * On error, returns an ERR_PTR value. */ struct iommu_sva * iommu_sva_bind_device(struct device *dev, struct mm_struct *mm, void *drvdata) { struct iommu_group *group; struct iommu_sva *handle = ERR_PTR(-EINVAL); const struct iommu_ops *ops = dev_iommu_ops(dev); if (!ops->sva_bind) return ERR_PTR(-ENODEV); group = iommu_group_get(dev); if (!group) return ERR_PTR(-ENODEV); /* Ensure device count and domain don't change while we're binding */ mutex_lock(&group->mutex); /* * To keep things simple, SVA currently doesn't support IOMMU groups * with more than one device. Existing SVA-capable systems are not * affected by the problems that required IOMMU groups (lack of ACS * isolation, device ID aliasing and other hardware issues). */ if (iommu_group_device_count(group) != 1) goto out_unlock; handle = ops->sva_bind(dev, mm, drvdata); out_unlock: mutex_unlock(&group->mutex); iommu_group_put(group); return handle; } EXPORT_SYMBOL_GPL(iommu_sva_bind_device); /** * iommu_sva_unbind_device() - Remove a bond created with iommu_sva_bind_device * @handle: the handle returned by iommu_sva_bind_device() * * Put reference to a bond between device and address space. The device should * not be issuing any more transaction for this PASID. All outstanding page * requests for this PASID must have been flushed to the IOMMU. */ void iommu_sva_unbind_device(struct iommu_sva *handle) { struct iommu_group *group; struct device *dev = handle->dev; const struct iommu_ops *ops = dev_iommu_ops(dev); if (!ops->sva_unbind) return; group = iommu_group_get(dev); if (!group) return; mutex_lock(&group->mutex); ops->sva_unbind(handle); mutex_unlock(&group->mutex); iommu_group_put(group); } EXPORT_SYMBOL_GPL(iommu_sva_unbind_device); u32 iommu_sva_get_pasid(struct iommu_sva *handle) { const struct iommu_ops *ops = dev_iommu_ops(handle->dev); if (!ops->sva_get_pasid) return IOMMU_PASID_INVALID; return ops->sva_get_pasid(handle); } EXPORT_SYMBOL_GPL(iommu_sva_get_pasid); /* * Changes the default domain of an iommu group that has *only* one device * * @group: The group for which the default domain should be changed * @prev_dev: The device in the group (this is used to make sure that the device * hasn't changed after the caller has called this function) * @type: The type of the new default domain that gets associated with the group * * Returns 0 on success and error code on failure * * Note: * 1. Presently, this function is called only when user requests to change the * group's default domain type through /sys/kernel/iommu_groups//type * Please take a closer look if intended to use for other purposes. */ static int iommu_change_dev_def_domain(struct iommu_group *group, struct device *prev_dev, int type) { struct iommu_domain *prev_dom; struct group_device *grp_dev; int ret, dev_def_dom; struct device *dev; mutex_lock(&group->mutex); if (group->default_domain != group->domain) { dev_err_ratelimited(prev_dev, "Group not assigned to default domain\n"); ret = -EBUSY; goto out; } /* * iommu group wasn't locked while acquiring device lock in * iommu_group_store_type(). So, make sure that the device count hasn't * changed while acquiring device lock. * * Changing default domain of an iommu group with two or more devices * isn't supported because there could be a potential deadlock. Consider * the following scenario. T1 is trying to acquire device locks of all * the devices in the group and before it could acquire all of them, * there could be another thread T2 (from different sub-system and use * case) that has already acquired some of the device locks and might be * waiting for T1 to release other device locks. */ if (iommu_group_device_count(group) != 1) { dev_err_ratelimited(prev_dev, "Cannot change default domain: Group has more than one device\n"); ret = -EINVAL; goto out; } /* Since group has only one device */ grp_dev = list_first_entry(&group->devices, struct group_device, list); dev = grp_dev->dev; if (prev_dev != dev) { dev_err_ratelimited(prev_dev, "Cannot change default domain: Device has been changed\n"); ret = -EBUSY; goto out; } prev_dom = group->default_domain; if (!prev_dom) { ret = -EINVAL; goto out; } dev_def_dom = iommu_get_def_domain_type(dev); if (!type) { /* * If the user hasn't requested any specific type of domain and * if the device supports both the domains, then default to the * domain the device was booted with */ type = dev_def_dom ? : iommu_def_domain_type; } else if (dev_def_dom && type != dev_def_dom) { dev_err_ratelimited(prev_dev, "Device cannot be in %s domain\n", iommu_domain_type_str(type)); ret = -EINVAL; goto out; } /* * Switch to a new domain only if the requested domain type is different * from the existing default domain type */ if (prev_dom->type == type) { ret = 0; goto out; } /* We can bring up a flush queue without tearing down the domain */ if (type == IOMMU_DOMAIN_DMA_FQ && prev_dom->type == IOMMU_DOMAIN_DMA) { ret = iommu_dma_init_fq(prev_dom); if (!ret) prev_dom->type = IOMMU_DOMAIN_DMA_FQ; goto out; } /* Sets group->default_domain to the newly allocated domain */ ret = iommu_group_alloc_default_domain(dev->bus, group, type); if (ret) goto out; ret = iommu_create_device_direct_mappings(group, dev); if (ret) goto free_new_domain; ret = __iommu_attach_device(group->default_domain, dev); if (ret) goto free_new_domain; group->domain = group->default_domain; /* * Release the mutex here because ops->probe_finalize() call-back of * some vendor IOMMU drivers calls arm_iommu_attach_device() which * in-turn might call back into IOMMU core code, where it tries to take * group->mutex, resulting in a deadlock. */ mutex_unlock(&group->mutex); /* Make sure dma_ops is appropriatley set */ iommu_group_do_probe_finalize(dev, group->default_domain); iommu_domain_free(prev_dom); return 0; free_new_domain: iommu_domain_free(group->default_domain); group->default_domain = prev_dom; group->domain = prev_dom; out: mutex_unlock(&group->mutex); return ret; } /* * Changing the default domain through sysfs requires the users to unbind the * drivers from the devices in the iommu group, except for a DMA -> DMA-FQ * transition. Return failure if this isn't met. * * We need to consider the race between this and the device release path. * device_lock(dev) is used here to guarantee that the device release path * will not be entered at the same time. */ static ssize_t iommu_group_store_type(struct iommu_group *group, const char *buf, size_t count) { struct group_device *grp_dev; struct device *dev; int ret, req_type; if (!capable(CAP_SYS_ADMIN) || !capable(CAP_SYS_RAWIO)) return -EACCES; if (WARN_ON(!group) || !group->default_domain) return -EINVAL; if (sysfs_streq(buf, "identity")) req_type = IOMMU_DOMAIN_IDENTITY; else if (sysfs_streq(buf, "DMA")) req_type = IOMMU_DOMAIN_DMA; else if (sysfs_streq(buf, "DMA-FQ")) req_type = IOMMU_DOMAIN_DMA_FQ; else if (sysfs_streq(buf, "auto")) req_type = 0; else return -EINVAL; /* * Lock/Unlock the group mutex here before device lock to * 1. Make sure that the iommu group has only one device (this is a * prerequisite for step 2) * 2. Get struct *dev which is needed to lock device */ mutex_lock(&group->mutex); if (iommu_group_device_count(group) != 1) { mutex_unlock(&group->mutex); pr_err_ratelimited("Cannot change default domain: Group has more than one device\n"); return -EINVAL; } /* Since group has only one device */ grp_dev = list_first_entry(&group->devices, struct group_device, list); dev = grp_dev->dev; get_device(dev); /* * Don't hold the group mutex because taking group mutex first and then * the device lock could potentially cause a deadlock as below. Assume * two threads T1 and T2. T1 is trying to change default domain of an * iommu group and T2 is trying to hot unplug a device or release [1] VF * of a PCIe device which is in the same iommu group. T1 takes group * mutex and before it could take device lock assume T2 has taken device * lock and is yet to take group mutex. Now, both the threads will be * waiting for the other thread to release lock. Below, lock order was * suggested. * device_lock(dev); * mutex_lock(&group->mutex); * iommu_change_dev_def_domain(); * mutex_unlock(&group->mutex); * device_unlock(dev); * * [1] Typical device release path * device_lock() from device/driver core code * -> bus_notifier() * -> iommu_bus_notifier() * -> iommu_release_device() * -> ops->release_device() vendor driver calls back iommu core code * -> mutex_lock() from iommu core code */ mutex_unlock(&group->mutex); /* Check if the device in the group still has a driver bound to it */ device_lock(dev); if (device_is_bound(dev) && !(req_type == IOMMU_DOMAIN_DMA_FQ && group->default_domain->type == IOMMU_DOMAIN_DMA)) { pr_err_ratelimited("Device is still bound to driver\n"); ret = -EBUSY; goto out; } ret = iommu_change_dev_def_domain(group, dev, req_type); ret = ret ?: count; out: device_unlock(dev); put_device(dev); return ret; } /** * iommu_device_use_default_domain() - Device driver wants to handle device * DMA through the kernel DMA API. * @dev: The device. * * The device driver about to bind @dev wants to do DMA through the kernel * DMA API. Return 0 if it is allowed, otherwise an error. */ int iommu_device_use_default_domain(struct device *dev) { struct iommu_group *group = iommu_group_get(dev); int ret = 0; if (!group) return 0; mutex_lock(&group->mutex); if (group->owner_cnt) { if (group->domain != group->default_domain || group->owner) { ret = -EBUSY; goto unlock_out; } } group->owner_cnt++; unlock_out: mutex_unlock(&group->mutex); iommu_group_put(group); return ret; } /** * iommu_device_unuse_default_domain() - Device driver stops handling device * DMA through the kernel DMA API. * @dev: The device. * * The device driver doesn't want to do DMA through kernel DMA API anymore. * It must be called after iommu_device_use_default_domain(). */ void iommu_device_unuse_default_domain(struct device *dev) { struct iommu_group *group = iommu_group_get(dev); if (!group) return; mutex_lock(&group->mutex); if (!WARN_ON(!group->owner_cnt)) group->owner_cnt--; mutex_unlock(&group->mutex); iommu_group_put(group); } static int __iommu_group_alloc_blocking_domain(struct iommu_group *group) { struct group_device *dev = list_first_entry(&group->devices, struct group_device, list); if (group->blocking_domain) return 0; group->blocking_domain = __iommu_domain_alloc(dev->dev->bus, IOMMU_DOMAIN_BLOCKED); if (!group->blocking_domain) { /* * For drivers that do not yet understand IOMMU_DOMAIN_BLOCKED * create an empty domain instead. */ group->blocking_domain = __iommu_domain_alloc( dev->dev->bus, IOMMU_DOMAIN_UNMANAGED); if (!group->blocking_domain) return -EINVAL; } return 0; } /** * iommu_group_claim_dma_owner() - Set DMA ownership of a group * @group: The group. * @owner: Caller specified pointer. Used for exclusive ownership. * * This is to support backward compatibility for vfio which manages * the dma ownership in iommu_group level. New invocations on this * interface should be prohibited. */ int iommu_group_claim_dma_owner(struct iommu_group *group, void *owner) { int ret = 0; mutex_lock(&group->mutex); if (group->owner_cnt) { ret = -EPERM; goto unlock_out; } else { if (group->domain && group->domain != group->default_domain) { ret = -EBUSY; goto unlock_out; } ret = __iommu_group_alloc_blocking_domain(group); if (ret) goto unlock_out; ret = __iommu_group_set_domain(group, group->blocking_domain); if (ret) goto unlock_out; group->owner = owner; } group->owner_cnt++; unlock_out: mutex_unlock(&group->mutex); return ret; } EXPORT_SYMBOL_GPL(iommu_group_claim_dma_owner); /** * iommu_group_release_dma_owner() - Release DMA ownership of a group * @group: The group. * * Release the DMA ownership claimed by iommu_group_claim_dma_owner(). */ void iommu_group_release_dma_owner(struct iommu_group *group) { int ret; mutex_lock(&group->mutex); if (WARN_ON(!group->owner_cnt || !group->owner)) goto unlock_out; group->owner_cnt = 0; group->owner = NULL; ret = __iommu_group_set_domain(group, group->default_domain); WARN(ret, "iommu driver failed to attach the default domain"); unlock_out: mutex_unlock(&group->mutex); } EXPORT_SYMBOL_GPL(iommu_group_release_dma_owner); /** * iommu_group_dma_owner_claimed() - Query group dma ownership status * @group: The group. * * This provides status query on a given group. It is racy and only for * non-binding status reporting. */ bool iommu_group_dma_owner_claimed(struct iommu_group *group) { unsigned int user; mutex_lock(&group->mutex); user = group->owner_cnt; mutex_unlock(&group->mutex); return user; } EXPORT_SYMBOL_GPL(iommu_group_dma_owner_claimed);