From 2c3c1048746a4622d8c89a29670120dc8fab93c4 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sun, 7 Apr 2024 20:49:45 +0200 Subject: Adding upstream version 6.1.76. Signed-off-by: Daniel Baumann --- drivers/iommu/ioasid.c | 422 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 422 insertions(+) create mode 100644 drivers/iommu/ioasid.c (limited to 'drivers/iommu/ioasid.c') diff --git a/drivers/iommu/ioasid.c b/drivers/iommu/ioasid.c new file mode 100644 index 000000000..a786c0349 --- /dev/null +++ b/drivers/iommu/ioasid.c @@ -0,0 +1,422 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * I/O Address Space ID allocator. There is one global IOASID space, split into + * subsets. Users create a subset with DECLARE_IOASID_SET, then allocate and + * free IOASIDs with ioasid_alloc() and ioasid_free(). + */ +#include +#include +#include +#include +#include + +struct ioasid_data { + ioasid_t id; + struct ioasid_set *set; + void *private; + struct rcu_head rcu; +}; + +/* + * struct ioasid_allocator_data - Internal data structure to hold information + * about an allocator. There are two types of allocators: + * + * - Default allocator always has its own XArray to track the IOASIDs allocated. + * - Custom allocators may share allocation helpers with different private data. + * Custom allocators that share the same helper functions also share the same + * XArray. + * Rules: + * 1. Default allocator is always available, not dynamically registered. This is + * to prevent race conditions with early boot code that want to register + * custom allocators or allocate IOASIDs. + * 2. Custom allocators take precedence over the default allocator. + * 3. When all custom allocators sharing the same helper functions are + * unregistered (e.g. due to hotplug), all outstanding IOASIDs must be + * freed. Otherwise, outstanding IOASIDs will be lost and orphaned. + * 4. When switching between custom allocators sharing the same helper + * functions, outstanding IOASIDs are preserved. + * 5. When switching between custom allocator and default allocator, all IOASIDs + * must be freed to ensure unadulterated space for the new allocator. + * + * @ops: allocator helper functions and its data + * @list: registered custom allocators + * @slist: allocators share the same ops but different data + * @flags: attributes of the allocator + * @xa: xarray holds the IOASID space + * @rcu: used for kfree_rcu when unregistering allocator + */ +struct ioasid_allocator_data { + struct ioasid_allocator_ops *ops; + struct list_head list; + struct list_head slist; +#define IOASID_ALLOCATOR_CUSTOM BIT(0) /* Needs framework to track results */ + unsigned long flags; + struct xarray xa; + struct rcu_head rcu; +}; + +static DEFINE_SPINLOCK(ioasid_allocator_lock); +static LIST_HEAD(allocators_list); + +static ioasid_t default_alloc(ioasid_t min, ioasid_t max, void *opaque); +static void default_free(ioasid_t ioasid, void *opaque); + +static struct ioasid_allocator_ops default_ops = { + .alloc = default_alloc, + .free = default_free, +}; + +static struct ioasid_allocator_data default_allocator = { + .ops = &default_ops, + .flags = 0, + .xa = XARRAY_INIT(ioasid_xa, XA_FLAGS_ALLOC), +}; + +static struct ioasid_allocator_data *active_allocator = &default_allocator; + +static ioasid_t default_alloc(ioasid_t min, ioasid_t max, void *opaque) +{ + ioasid_t id; + + if (xa_alloc(&default_allocator.xa, &id, opaque, XA_LIMIT(min, max), GFP_ATOMIC)) { + pr_err("Failed to alloc ioasid from %d to %d\n", min, max); + return INVALID_IOASID; + } + + return id; +} + +static void default_free(ioasid_t ioasid, void *opaque) +{ + struct ioasid_data *ioasid_data; + + ioasid_data = xa_erase(&default_allocator.xa, ioasid); + kfree_rcu(ioasid_data, rcu); +} + +/* Allocate and initialize a new custom allocator with its helper functions */ +static struct ioasid_allocator_data *ioasid_alloc_allocator(struct ioasid_allocator_ops *ops) +{ + struct ioasid_allocator_data *ia_data; + + ia_data = kzalloc(sizeof(*ia_data), GFP_ATOMIC); + if (!ia_data) + return NULL; + + xa_init_flags(&ia_data->xa, XA_FLAGS_ALLOC); + INIT_LIST_HEAD(&ia_data->slist); + ia_data->flags |= IOASID_ALLOCATOR_CUSTOM; + ia_data->ops = ops; + + /* For tracking custom allocators that share the same ops */ + list_add_tail(&ops->list, &ia_data->slist); + + return ia_data; +} + +static bool use_same_ops(struct ioasid_allocator_ops *a, struct ioasid_allocator_ops *b) +{ + return (a->free == b->free) && (a->alloc == b->alloc); +} + +/** + * ioasid_register_allocator - register a custom allocator + * @ops: the custom allocator ops to be registered + * + * Custom allocators take precedence over the default xarray based allocator. + * Private data associated with the IOASID allocated by the custom allocators + * are managed by IOASID framework similar to data stored in xa by default + * allocator. + * + * There can be multiple allocators registered but only one is active. In case + * of runtime removal of a custom allocator, the next one is activated based + * on the registration ordering. + * + * Multiple allocators can share the same alloc() function, in this case the + * IOASID space is shared. + */ +int ioasid_register_allocator(struct ioasid_allocator_ops *ops) +{ + struct ioasid_allocator_data *ia_data; + struct ioasid_allocator_data *pallocator; + int ret = 0; + + spin_lock(&ioasid_allocator_lock); + + ia_data = ioasid_alloc_allocator(ops); + if (!ia_data) { + ret = -ENOMEM; + goto out_unlock; + } + + /* + * No particular preference, we activate the first one and keep + * the later registered allocators in a list in case the first one gets + * removed due to hotplug. + */ + if (list_empty(&allocators_list)) { + WARN_ON(active_allocator != &default_allocator); + /* Use this new allocator if default is not active */ + if (xa_empty(&active_allocator->xa)) { + rcu_assign_pointer(active_allocator, ia_data); + list_add_tail(&ia_data->list, &allocators_list); + goto out_unlock; + } + pr_warn("Default allocator active with outstanding IOASID\n"); + ret = -EAGAIN; + goto out_free; + } + + /* Check if the allocator is already registered */ + list_for_each_entry(pallocator, &allocators_list, list) { + if (pallocator->ops == ops) { + pr_err("IOASID allocator already registered\n"); + ret = -EEXIST; + goto out_free; + } else if (use_same_ops(pallocator->ops, ops)) { + /* + * If the new allocator shares the same ops, + * then they will share the same IOASID space. + * We should put them under the same xarray. + */ + list_add_tail(&ops->list, &pallocator->slist); + goto out_free; + } + } + list_add_tail(&ia_data->list, &allocators_list); + + spin_unlock(&ioasid_allocator_lock); + return 0; +out_free: + kfree(ia_data); +out_unlock: + spin_unlock(&ioasid_allocator_lock); + return ret; +} +EXPORT_SYMBOL_GPL(ioasid_register_allocator); + +/** + * ioasid_unregister_allocator - Remove a custom IOASID allocator ops + * @ops: the custom allocator to be removed + * + * Remove an allocator from the list, activate the next allocator in + * the order it was registered. Or revert to default allocator if all + * custom allocators are unregistered without outstanding IOASIDs. + */ +void ioasid_unregister_allocator(struct ioasid_allocator_ops *ops) +{ + struct ioasid_allocator_data *pallocator; + struct ioasid_allocator_ops *sops; + + spin_lock(&ioasid_allocator_lock); + if (list_empty(&allocators_list)) { + pr_warn("No custom IOASID allocators active!\n"); + goto exit_unlock; + } + + list_for_each_entry(pallocator, &allocators_list, list) { + if (!use_same_ops(pallocator->ops, ops)) + continue; + + if (list_is_singular(&pallocator->slist)) { + /* No shared helper functions */ + list_del(&pallocator->list); + /* + * All IOASIDs should have been freed before + * the last allocator that shares the same ops + * is unregistered. + */ + WARN_ON(!xa_empty(&pallocator->xa)); + if (list_empty(&allocators_list)) { + pr_info("No custom IOASID allocators, switch to default.\n"); + rcu_assign_pointer(active_allocator, &default_allocator); + } else if (pallocator == active_allocator) { + rcu_assign_pointer(active_allocator, + list_first_entry(&allocators_list, + struct ioasid_allocator_data, list)); + pr_info("IOASID allocator changed"); + } + kfree_rcu(pallocator, rcu); + break; + } + /* + * Find the matching shared ops to delete, + * but keep outstanding IOASIDs + */ + list_for_each_entry(sops, &pallocator->slist, list) { + if (sops == ops) { + list_del(&ops->list); + break; + } + } + break; + } + +exit_unlock: + spin_unlock(&ioasid_allocator_lock); +} +EXPORT_SYMBOL_GPL(ioasid_unregister_allocator); + +/** + * ioasid_set_data - Set private data for an allocated ioasid + * @ioasid: the ID to set data + * @data: the private data + * + * For IOASID that is already allocated, private data can be set + * via this API. Future lookup can be done via ioasid_find. + */ +int ioasid_set_data(ioasid_t ioasid, void *data) +{ + struct ioasid_data *ioasid_data; + int ret = 0; + + spin_lock(&ioasid_allocator_lock); + ioasid_data = xa_load(&active_allocator->xa, ioasid); + if (ioasid_data) + rcu_assign_pointer(ioasid_data->private, data); + else + ret = -ENOENT; + spin_unlock(&ioasid_allocator_lock); + + /* + * Wait for readers to stop accessing the old private data, so the + * caller can free it. + */ + if (!ret) + synchronize_rcu(); + + return ret; +} +EXPORT_SYMBOL_GPL(ioasid_set_data); + +/** + * ioasid_alloc - Allocate an IOASID + * @set: the IOASID set + * @min: the minimum ID (inclusive) + * @max: the maximum ID (inclusive) + * @private: data private to the caller + * + * Allocate an ID between @min and @max. The @private pointer is stored + * internally and can be retrieved with ioasid_find(). + * + * Return: the allocated ID on success, or %INVALID_IOASID on failure. + */ +ioasid_t ioasid_alloc(struct ioasid_set *set, ioasid_t min, ioasid_t max, + void *private) +{ + struct ioasid_data *data; + void *adata; + ioasid_t id; + + data = kzalloc(sizeof(*data), GFP_ATOMIC); + if (!data) + return INVALID_IOASID; + + data->set = set; + data->private = private; + + /* + * Custom allocator needs allocator data to perform platform specific + * operations. + */ + spin_lock(&ioasid_allocator_lock); + adata = active_allocator->flags & IOASID_ALLOCATOR_CUSTOM ? active_allocator->ops->pdata : data; + id = active_allocator->ops->alloc(min, max, adata); + if (id == INVALID_IOASID) { + pr_err("Failed ASID allocation %lu\n", active_allocator->flags); + goto exit_free; + } + + if ((active_allocator->flags & IOASID_ALLOCATOR_CUSTOM) && + xa_alloc(&active_allocator->xa, &id, data, XA_LIMIT(id, id), GFP_ATOMIC)) { + /* Custom allocator needs framework to store and track allocation results */ + pr_err("Failed to alloc ioasid from %d\n", id); + active_allocator->ops->free(id, active_allocator->ops->pdata); + goto exit_free; + } + data->id = id; + + spin_unlock(&ioasid_allocator_lock); + return id; +exit_free: + spin_unlock(&ioasid_allocator_lock); + kfree(data); + return INVALID_IOASID; +} +EXPORT_SYMBOL_GPL(ioasid_alloc); + +/** + * ioasid_free - Free an ioasid + * @ioasid: the ID to remove + */ +void ioasid_free(ioasid_t ioasid) +{ + struct ioasid_data *ioasid_data; + + spin_lock(&ioasid_allocator_lock); + ioasid_data = xa_load(&active_allocator->xa, ioasid); + if (!ioasid_data) { + pr_err("Trying to free unknown IOASID %u\n", ioasid); + goto exit_unlock; + } + + active_allocator->ops->free(ioasid, active_allocator->ops->pdata); + /* Custom allocator needs additional steps to free the xa element */ + if (active_allocator->flags & IOASID_ALLOCATOR_CUSTOM) { + ioasid_data = xa_erase(&active_allocator->xa, ioasid); + kfree_rcu(ioasid_data, rcu); + } + +exit_unlock: + spin_unlock(&ioasid_allocator_lock); +} +EXPORT_SYMBOL_GPL(ioasid_free); + +/** + * ioasid_find - Find IOASID data + * @set: the IOASID set + * @ioasid: the IOASID to find + * @getter: function to call on the found object + * + * The optional getter function allows to take a reference to the found object + * under the rcu lock. The function can also check if the object is still valid: + * if @getter returns false, then the object is invalid and NULL is returned. + * + * If the IOASID exists, return the private pointer passed to ioasid_alloc. + * Private data can be NULL if not set. Return an error if the IOASID is not + * found, or if @set is not NULL and the IOASID does not belong to the set. + */ +void *ioasid_find(struct ioasid_set *set, ioasid_t ioasid, + bool (*getter)(void *)) +{ + void *priv; + struct ioasid_data *ioasid_data; + struct ioasid_allocator_data *idata; + + rcu_read_lock(); + idata = rcu_dereference(active_allocator); + ioasid_data = xa_load(&idata->xa, ioasid); + if (!ioasid_data) { + priv = ERR_PTR(-ENOENT); + goto unlock; + } + if (set && ioasid_data->set != set) { + /* data found but does not belong to the set */ + priv = ERR_PTR(-EACCES); + goto unlock; + } + /* Now IOASID and its set is verified, we can return the private data */ + priv = rcu_dereference(ioasid_data->private); + if (getter && !getter(priv)) + priv = NULL; +unlock: + rcu_read_unlock(); + + return priv; +} +EXPORT_SYMBOL_GPL(ioasid_find); + +MODULE_AUTHOR("Jean-Philippe Brucker "); +MODULE_AUTHOR("Jacob Pan "); +MODULE_DESCRIPTION("IO Address Space ID (IOASID) allocator"); +MODULE_LICENSE("GPL"); -- cgit v1.2.3