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Diffstat (limited to 'drivers/gpu/drm/drm_gpusvm.c')
| -rw-r--r-- | drivers/gpu/drm/drm_gpusvm.c | 1572 |
1 files changed, 1572 insertions, 0 deletions
diff --git a/drivers/gpu/drm/drm_gpusvm.c b/drivers/gpu/drm/drm_gpusvm.c new file mode 100644 index 000000000000..5bb4c77db2c3 --- /dev/null +++ b/drivers/gpu/drm/drm_gpusvm.c @@ -0,0 +1,1572 @@ +// SPDX-License-Identifier: GPL-2.0-only OR MIT +/* + * Copyright © 2024 Intel Corporation + * + * Authors: + * Matthew Brost <matthew.brost@intel.com> + */ + +#include <linux/dma-mapping.h> +#include <linux/export.h> +#include <linux/hmm.h> +#include <linux/hugetlb_inline.h> +#include <linux/memremap.h> +#include <linux/mm_types.h> +#include <linux/slab.h> + +#include <drm/drm_device.h> +#include <drm/drm_gpusvm.h> +#include <drm/drm_pagemap.h> +#include <drm/drm_print.h> + +/** + * DOC: Overview + * + * GPU Shared Virtual Memory (GPU SVM) layer for the Direct Rendering Manager (DRM) + * is a component of the DRM framework designed to manage shared virtual memory + * between the CPU and GPU. It enables efficient data exchange and processing + * for GPU-accelerated applications by allowing memory sharing and + * synchronization between the CPU's and GPU's virtual address spaces. + * + * Key GPU SVM Components: + * + * - Notifiers: + * Used for tracking memory intervals and notifying the GPU of changes, + * notifiers are sized based on a GPU SVM initialization parameter, with a + * recommendation of 512M or larger. They maintain a Red-BlacK tree and a + * list of ranges that fall within the notifier interval. Notifiers are + * tracked within a GPU SVM Red-BlacK tree and list and are dynamically + * inserted or removed as ranges within the interval are created or + * destroyed. + * - Ranges: + * Represent memory ranges mapped in a DRM device and managed by GPU SVM. + * They are sized based on an array of chunk sizes, which is a GPU SVM + * initialization parameter, and the CPU address space. Upon GPU fault, + * the largest aligned chunk that fits within the faulting CPU address + * space is chosen for the range size. Ranges are expected to be + * dynamically allocated on GPU fault and removed on an MMU notifier UNMAP + * event. As mentioned above, ranges are tracked in a notifier's Red-Black + * tree. + * + * - Operations: + * Define the interface for driver-specific GPU SVM operations such as + * range allocation, notifier allocation, and invalidations. + * + * - Device Memory Allocations: + * Embedded structure containing enough information for GPU SVM to migrate + * to / from device memory. + * + * - Device Memory Operations: + * Define the interface for driver-specific device memory operations + * release memory, populate pfns, and copy to / from device memory. + * + * This layer provides interfaces for allocating, mapping, migrating, and + * releasing memory ranges between the CPU and GPU. It handles all core memory + * management interactions (DMA mapping, HMM, and migration) and provides + * driver-specific virtual functions (vfuncs). This infrastructure is sufficient + * to build the expected driver components for an SVM implementation as detailed + * below. + * + * Expected Driver Components: + * + * - GPU page fault handler: + * Used to create ranges and notifiers based on the fault address, + * optionally migrate the range to device memory, and create GPU bindings. + * + * - Garbage collector: + * Used to unmap and destroy GPU bindings for ranges. Ranges are expected + * to be added to the garbage collector upon a MMU_NOTIFY_UNMAP event in + * notifier callback. + * + * - Notifier callback: + * Used to invalidate and DMA unmap GPU bindings for ranges. + */ + +/** + * DOC: Locking + * + * GPU SVM handles locking for core MM interactions, i.e., it locks/unlocks the + * mmap lock as needed. + * + * GPU SVM introduces a global notifier lock, which safeguards the notifier's + * range RB tree and list, as well as the range's DMA mappings and sequence + * number. GPU SVM manages all necessary locking and unlocking operations, + * except for the recheck range's pages being valid + * (drm_gpusvm_range_pages_valid) when the driver is committing GPU bindings. + * This lock corresponds to the ``driver->update`` lock mentioned in + * Documentation/mm/hmm.rst. Future revisions may transition from a GPU SVM + * global lock to a per-notifier lock if finer-grained locking is deemed + * necessary. + * + * In addition to the locking mentioned above, the driver should implement a + * lock to safeguard core GPU SVM function calls that modify state, such as + * drm_gpusvm_range_find_or_insert and drm_gpusvm_range_remove. This lock is + * denoted as 'driver_svm_lock' in code examples. Finer grained driver side + * locking should also be possible for concurrent GPU fault processing within a + * single GPU SVM. The 'driver_svm_lock' can be via drm_gpusvm_driver_set_lock + * to add annotations to GPU SVM. + */ + +/** + * DOC: Partial Unmapping of Ranges + * + * Partial unmapping of ranges (e.g., 1M out of 2M is unmapped by CPU resulting + * in MMU_NOTIFY_UNMAP event) presents several challenges, with the main one + * being that a subset of the range still has CPU and GPU mappings. If the + * backing store for the range is in device memory, a subset of the backing + * store has references. One option would be to split the range and device + * memory backing store, but the implementation for this would be quite + * complicated. Given that partial unmappings are rare and driver-defined range + * sizes are relatively small, GPU SVM does not support splitting of ranges. + * + * With no support for range splitting, upon partial unmapping of a range, the + * driver is expected to invalidate and destroy the entire range. If the range + * has device memory as its backing, the driver is also expected to migrate any + * remaining pages back to RAM. + */ + +/** + * DOC: Examples + * + * This section provides three examples of how to build the expected driver + * components: the GPU page fault handler, the garbage collector, and the + * notifier callback. + * + * The generic code provided does not include logic for complex migration + * policies, optimized invalidations, fined grained driver locking, or other + * potentially required driver locking (e.g., DMA-resv locks). + * + * 1) GPU page fault handler + * + * .. code-block:: c + * + * int driver_bind_range(struct drm_gpusvm *gpusvm, struct drm_gpusvm_range *range) + * { + * int err = 0; + * + * driver_alloc_and_setup_memory_for_bind(gpusvm, range); + * + * drm_gpusvm_notifier_lock(gpusvm); + * if (drm_gpusvm_range_pages_valid(range)) + * driver_commit_bind(gpusvm, range); + * else + * err = -EAGAIN; + * drm_gpusvm_notifier_unlock(gpusvm); + * + * return err; + * } + * + * int driver_gpu_fault(struct drm_gpusvm *gpusvm, unsigned long fault_addr, + * unsigned long gpuva_start, unsigned long gpuva_end) + * { + * struct drm_gpusvm_ctx ctx = {}; + * int err; + * + * driver_svm_lock(); + * retry: + * // Always process UNMAPs first so view of GPU SVM ranges is current + * driver_garbage_collector(gpusvm); + * + * range = drm_gpusvm_range_find_or_insert(gpusvm, fault_addr, + * gpuva_start, gpuva_end, + * &ctx); + * if (IS_ERR(range)) { + * err = PTR_ERR(range); + * goto unlock; + * } + * + * if (driver_migration_policy(range)) { + * err = drm_pagemap_populate_mm(driver_choose_drm_pagemap(), + * gpuva_start, gpuva_end, gpusvm->mm, + * ctx->timeslice_ms); + * if (err) // CPU mappings may have changed + * goto retry; + * } + * + * err = drm_gpusvm_range_get_pages(gpusvm, range, &ctx); + * if (err == -EOPNOTSUPP || err == -EFAULT || err == -EPERM) { // CPU mappings changed + * if (err == -EOPNOTSUPP) + * drm_gpusvm_range_evict(gpusvm, range); + * goto retry; + * } else if (err) { + * goto unlock; + * } + * + * err = driver_bind_range(gpusvm, range); + * if (err == -EAGAIN) // CPU mappings changed + * goto retry + * + * unlock: + * driver_svm_unlock(); + * return err; + * } + * + * 2) Garbage Collector + * + * .. code-block:: c + * + * void __driver_garbage_collector(struct drm_gpusvm *gpusvm, + * struct drm_gpusvm_range *range) + * { + * assert_driver_svm_locked(gpusvm); + * + * // Partial unmap, migrate any remaining device memory pages back to RAM + * if (range->flags.partial_unmap) + * drm_gpusvm_range_evict(gpusvm, range); + * + * driver_unbind_range(range); + * drm_gpusvm_range_remove(gpusvm, range); + * } + * + * void driver_garbage_collector(struct drm_gpusvm *gpusvm) + * { + * assert_driver_svm_locked(gpusvm); + * + * for_each_range_in_garbage_collector(gpusvm, range) + * __driver_garbage_collector(gpusvm, range); + * } + * + * 3) Notifier callback + * + * .. code-block:: c + * + * void driver_invalidation(struct drm_gpusvm *gpusvm, + * struct drm_gpusvm_notifier *notifier, + * const struct mmu_notifier_range *mmu_range) + * { + * struct drm_gpusvm_ctx ctx = { .in_notifier = true, }; + * struct drm_gpusvm_range *range = NULL; + * + * driver_invalidate_device_pages(gpusvm, mmu_range->start, mmu_range->end); + * + * drm_gpusvm_for_each_range(range, notifier, mmu_range->start, + * mmu_range->end) { + * drm_gpusvm_range_unmap_pages(gpusvm, range, &ctx); + * + * if (mmu_range->event != MMU_NOTIFY_UNMAP) + * continue; + * + * drm_gpusvm_range_set_unmapped(range, mmu_range); + * driver_garbage_collector_add(gpusvm, range); + * } + * } + */ + +/** + * npages_in_range() - Calculate the number of pages in a given range + * @start: The start address of the range + * @end: The end address of the range + * + * This macro calculates the number of pages in a given memory range, + * specified by the start and end addresses. It divides the difference + * between the end and start addresses by the page size (PAGE_SIZE) to + * determine the number of pages in the range. + * + * Return: The number of pages in the specified range. + */ +static unsigned long +npages_in_range(unsigned long start, unsigned long end) +{ + return (end - start) >> PAGE_SHIFT; +} + +/** + * drm_gpusvm_range_find() - Find GPU SVM range from GPU SVM notifier + * @notifier: Pointer to the GPU SVM notifier structure. + * @start: Start address of the range + * @end: End address of the range + * + * Return: A pointer to the drm_gpusvm_range if found or NULL + */ +struct drm_gpusvm_range * +drm_gpusvm_range_find(struct drm_gpusvm_notifier *notifier, unsigned long start, + unsigned long end) +{ + struct interval_tree_node *itree; + + itree = interval_tree_iter_first(¬ifier->root, start, end - 1); + + if (itree) + return container_of(itree, struct drm_gpusvm_range, itree); + else + return NULL; +} +EXPORT_SYMBOL_GPL(drm_gpusvm_range_find); + +/** + * drm_gpusvm_for_each_range_safe() - Safely iterate over GPU SVM ranges in a notifier + * @range__: Iterator variable for the ranges + * @next__: Iterator variable for the ranges temporay storage + * @notifier__: Pointer to the GPU SVM notifier + * @start__: Start address of the range + * @end__: End address of the range + * + * This macro is used to iterate over GPU SVM ranges in a notifier while + * removing ranges from it. + */ +#define drm_gpusvm_for_each_range_safe(range__, next__, notifier__, start__, end__) \ + for ((range__) = drm_gpusvm_range_find((notifier__), (start__), (end__)), \ + (next__) = __drm_gpusvm_range_next(range__); \ + (range__) && (drm_gpusvm_range_start(range__) < (end__)); \ + (range__) = (next__), (next__) = __drm_gpusvm_range_next(range__)) + +/** + * __drm_gpusvm_notifier_next() - get the next drm_gpusvm_notifier in the list + * @notifier: a pointer to the current drm_gpusvm_notifier + * + * Return: A pointer to the next drm_gpusvm_notifier if available, or NULL if + * the current notifier is the last one or if the input notifier is + * NULL. + */ +static struct drm_gpusvm_notifier * +__drm_gpusvm_notifier_next(struct drm_gpusvm_notifier *notifier) +{ + if (notifier && !list_is_last(¬ifier->entry, + ¬ifier->gpusvm->notifier_list)) + return list_next_entry(notifier, entry); + + return NULL; +} + +static struct drm_gpusvm_notifier * +notifier_iter_first(struct rb_root_cached *root, unsigned long start, + unsigned long last) +{ + struct interval_tree_node *itree; + + itree = interval_tree_iter_first(root, start, last); + + if (itree) + return container_of(itree, struct drm_gpusvm_notifier, itree); + else + return NULL; +} + +/** + * drm_gpusvm_for_each_notifier() - Iterate over GPU SVM notifiers in a gpusvm + * @notifier__: Iterator variable for the notifiers + * @notifier__: Pointer to the GPU SVM notifier + * @start__: Start address of the notifier + * @end__: End address of the notifier + * + * This macro is used to iterate over GPU SVM notifiers in a gpusvm. + */ +#define drm_gpusvm_for_each_notifier(notifier__, gpusvm__, start__, end__) \ + for ((notifier__) = notifier_iter_first(&(gpusvm__)->root, (start__), (end__) - 1); \ + (notifier__) && (drm_gpusvm_notifier_start(notifier__) < (end__)); \ + (notifier__) = __drm_gpusvm_notifier_next(notifier__)) + +/** + * drm_gpusvm_for_each_notifier_safe() - Safely iterate over GPU SVM notifiers in a gpusvm + * @notifier__: Iterator variable for the notifiers + * @next__: Iterator variable for the notifiers temporay storage + * @notifier__: Pointer to the GPU SVM notifier + * @start__: Start address of the notifier + * @end__: End address of the notifier + * + * This macro is used to iterate over GPU SVM notifiers in a gpusvm while + * removing notifiers from it. + */ +#define drm_gpusvm_for_each_notifier_safe(notifier__, next__, gpusvm__, start__, end__) \ + for ((notifier__) = notifier_iter_first(&(gpusvm__)->root, (start__), (end__) - 1), \ + (next__) = __drm_gpusvm_notifier_next(notifier__); \ + (notifier__) && (drm_gpusvm_notifier_start(notifier__) < (end__)); \ + (notifier__) = (next__), (next__) = __drm_gpusvm_notifier_next(notifier__)) + +/** + * drm_gpusvm_notifier_invalidate() - Invalidate a GPU SVM notifier. + * @mni: Pointer to the mmu_interval_notifier structure. + * @mmu_range: Pointer to the mmu_notifier_range structure. + * @cur_seq: Current sequence number. + * + * This function serves as a generic MMU notifier for GPU SVM. It sets the MMU + * notifier sequence number and calls the driver invalidate vfunc under + * gpusvm->notifier_lock. + * + * Return: true if the operation succeeds, false otherwise. + */ +static bool +drm_gpusvm_notifier_invalidate(struct mmu_interval_notifier *mni, + const struct mmu_notifier_range *mmu_range, + unsigned long cur_seq) +{ + struct drm_gpusvm_notifier *notifier = + container_of(mni, typeof(*notifier), notifier); + struct drm_gpusvm *gpusvm = notifier->gpusvm; + + if (!mmu_notifier_range_blockable(mmu_range)) + return false; + + down_write(&gpusvm->notifier_lock); + mmu_interval_set_seq(mni, cur_seq); + gpusvm->ops->invalidate(gpusvm, notifier, mmu_range); + up_write(&gpusvm->notifier_lock); + + return true; +} + +/* + * drm_gpusvm_notifier_ops - MMU interval notifier operations for GPU SVM + */ +static const struct mmu_interval_notifier_ops drm_gpusvm_notifier_ops = { + .invalidate = drm_gpusvm_notifier_invalidate, +}; + +/** + * drm_gpusvm_init() - Initialize the GPU SVM. + * @gpusvm: Pointer to the GPU SVM structure. + * @name: Name of the GPU SVM. + * @drm: Pointer to the DRM device structure. + * @mm: Pointer to the mm_struct for the address space. + * @device_private_page_owner: Device private pages owner. + * @mm_start: Start address of GPU SVM. + * @mm_range: Range of the GPU SVM. + * @notifier_size: Size of individual notifiers. + * @ops: Pointer to the operations structure for GPU SVM. + * @chunk_sizes: Pointer to the array of chunk sizes used in range allocation. + * Entries should be powers of 2 in descending order with last + * entry being SZ_4K. + * @num_chunks: Number of chunks. + * + * This function initializes the GPU SVM. + * + * Return: 0 on success, a negative error code on failure. + */ +int drm_gpusvm_init(struct drm_gpusvm *gpusvm, + const char *name, struct drm_device *drm, + struct mm_struct *mm, void *device_private_page_owner, + unsigned long mm_start, unsigned long mm_range, + unsigned long notifier_size, + const struct drm_gpusvm_ops *ops, + const unsigned long *chunk_sizes, int num_chunks) +{ + if (!ops->invalidate || !num_chunks) + return -EINVAL; + + gpusvm->name = name; + gpusvm->drm = drm; + gpusvm->mm = mm; + gpusvm->device_private_page_owner = device_private_page_owner; + gpusvm->mm_start = mm_start; + gpusvm->mm_range = mm_range; + gpusvm->notifier_size = notifier_size; + gpusvm->ops = ops; + gpusvm->chunk_sizes = chunk_sizes; + gpusvm->num_chunks = num_chunks; + + mmgrab(mm); + gpusvm->root = RB_ROOT_CACHED; + INIT_LIST_HEAD(&gpusvm->notifier_list); + + init_rwsem(&gpusvm->notifier_lock); + + fs_reclaim_acquire(GFP_KERNEL); + might_lock(&gpusvm->notifier_lock); + fs_reclaim_release(GFP_KERNEL); + +#ifdef CONFIG_LOCKDEP + gpusvm->lock_dep_map = NULL; +#endif + + return 0; +} +EXPORT_SYMBOL_GPL(drm_gpusvm_init); + +/** + * drm_gpusvm_notifier_find() - Find GPU SVM notifier + * @gpusvm: Pointer to the GPU SVM structure + * @fault_addr: Fault address + * + * This function finds the GPU SVM notifier associated with the fault address. + * + * Return: Pointer to the GPU SVM notifier on success, NULL otherwise. + */ +static struct drm_gpusvm_notifier * +drm_gpusvm_notifier_find(struct drm_gpusvm *gpusvm, + unsigned long fault_addr) +{ + return notifier_iter_first(&gpusvm->root, fault_addr, fault_addr + 1); +} + +/** + * to_drm_gpusvm_notifier() - retrieve the container struct for a given rbtree node + * @node: a pointer to the rbtree node embedded within a drm_gpusvm_notifier struct + * + * Return: A pointer to the containing drm_gpusvm_notifier structure. + */ +static struct drm_gpusvm_notifier *to_drm_gpusvm_notifier(struct rb_node *node) +{ + return container_of(node, struct drm_gpusvm_notifier, itree.rb); +} + +/** + * drm_gpusvm_notifier_insert() - Insert GPU SVM notifier + * @gpusvm: Pointer to the GPU SVM structure + * @notifier: Pointer to the GPU SVM notifier structure + * + * This function inserts the GPU SVM notifier into the GPU SVM RB tree and list. + */ +static void drm_gpusvm_notifier_insert(struct drm_gpusvm *gpusvm, + struct drm_gpusvm_notifier *notifier) +{ + struct rb_node *node; + struct list_head *head; + + interval_tree_insert(¬ifier->itree, &gpusvm->root); + + node = rb_prev(¬ifier->itree.rb); + if (node) + head = &(to_drm_gpusvm_notifier(node))->entry; + else + head = &gpusvm->notifier_list; + + list_add(¬ifier->entry, head); +} + +/** + * drm_gpusvm_notifier_remove() - Remove GPU SVM notifier + * @gpusvm: Pointer to the GPU SVM tructure + * @notifier: Pointer to the GPU SVM notifier structure + * + * This function removes the GPU SVM notifier from the GPU SVM RB tree and list. + */ +static void drm_gpusvm_notifier_remove(struct drm_gpusvm *gpusvm, + struct drm_gpusvm_notifier *notifier) +{ + interval_tree_remove(¬ifier->itree, &gpusvm->root); + list_del(¬ifier->entry); +} + +/** + * drm_gpusvm_fini() - Finalize the GPU SVM. + * @gpusvm: Pointer to the GPU SVM structure. + * + * This function finalizes the GPU SVM by cleaning up any remaining ranges and + * notifiers, and dropping a reference to struct MM. + */ +void drm_gpusvm_fini(struct drm_gpusvm *gpusvm) +{ + struct drm_gpusvm_notifier *notifier, *next; + + drm_gpusvm_for_each_notifier_safe(notifier, next, gpusvm, 0, LONG_MAX) { + struct drm_gpusvm_range *range, *__next; + + /* + * Remove notifier first to avoid racing with any invalidation + */ + mmu_interval_notifier_remove(¬ifier->notifier); + notifier->flags.removed = true; + + drm_gpusvm_for_each_range_safe(range, __next, notifier, 0, + LONG_MAX) + drm_gpusvm_range_remove(gpusvm, range); + } + + mmdrop(gpusvm->mm); + WARN_ON(!RB_EMPTY_ROOT(&gpusvm->root.rb_root)); +} +EXPORT_SYMBOL_GPL(drm_gpusvm_fini); + +/** + * drm_gpusvm_notifier_alloc() - Allocate GPU SVM notifier + * @gpusvm: Pointer to the GPU SVM structure + * @fault_addr: Fault address + * + * This function allocates and initializes the GPU SVM notifier structure. + * + * Return: Pointer to the allocated GPU SVM notifier on success, ERR_PTR() on failure. + */ +static struct drm_gpusvm_notifier * +drm_gpusvm_notifier_alloc(struct drm_gpusvm *gpusvm, unsigned long fault_addr) +{ + struct drm_gpusvm_notifier *notifier; + + if (gpusvm->ops->notifier_alloc) + notifier = gpusvm->ops->notifier_alloc(); + else + notifier = kzalloc(sizeof(*notifier), GFP_KERNEL); + + if (!notifier) + return ERR_PTR(-ENOMEM); + + notifier->gpusvm = gpusvm; + notifier->itree.start = ALIGN_DOWN(fault_addr, gpusvm->notifier_size); + notifier->itree.last = ALIGN(fault_addr + 1, gpusvm->notifier_size) - 1; + INIT_LIST_HEAD(¬ifier->entry); + notifier->root = RB_ROOT_CACHED; + INIT_LIST_HEAD(¬ifier->range_list); + + return notifier; +} + +/** + * drm_gpusvm_notifier_free() - Free GPU SVM notifier + * @gpusvm: Pointer to the GPU SVM structure + * @notifier: Pointer to the GPU SVM notifier structure + * + * This function frees the GPU SVM notifier structure. + */ +static void drm_gpusvm_notifier_free(struct drm_gpusvm *gpusvm, + struct drm_gpusvm_notifier *notifier) +{ + WARN_ON(!RB_EMPTY_ROOT(¬ifier->root.rb_root)); + + if (gpusvm->ops->notifier_free) + gpusvm->ops->notifier_free(notifier); + else + kfree(notifier); +} + +/** + * to_drm_gpusvm_range() - retrieve the container struct for a given rbtree node + * @node: a pointer to the rbtree node embedded within a drm_gpusvm_range struct + * + * Return: A pointer to the containing drm_gpusvm_range structure. + */ +static struct drm_gpusvm_range *to_drm_gpusvm_range(struct rb_node *node) +{ + return container_of(node, struct drm_gpusvm_range, itree.rb); +} + +/** + * drm_gpusvm_range_insert() - Insert GPU SVM range + * @notifier: Pointer to the GPU SVM notifier structure + * @range: Pointer to the GPU SVM range structure + * + * This function inserts the GPU SVM range into the notifier RB tree and list. + */ +static void drm_gpusvm_range_insert(struct drm_gpusvm_notifier *notifier, + struct drm_gpusvm_range *range) +{ + struct rb_node *node; + struct list_head *head; + + drm_gpusvm_notifier_lock(notifier->gpusvm); + interval_tree_insert(&range->itree, ¬ifier->root); + + node = rb_prev(&range->itree.rb); + if (node) + head = &(to_drm_gpusvm_range(node))->entry; + else + head = ¬ifier->range_list; + + list_add(&range->entry, head); + drm_gpusvm_notifier_unlock(notifier->gpusvm); +} + +/** + * __drm_gpusvm_range_remove() - Remove GPU SVM range + * @notifier: Pointer to the GPU SVM notifier structure + * @range: Pointer to the GPU SVM range structure + * + * This macro removes the GPU SVM range from the notifier RB tree and list. + */ +static void __drm_gpusvm_range_remove(struct drm_gpusvm_notifier *notifier, + struct drm_gpusvm_range *range) +{ + interval_tree_remove(&range->itree, ¬ifier->root); + list_del(&range->entry); +} + +/** + * drm_gpusvm_range_alloc() - Allocate GPU SVM range + * @gpusvm: Pointer to the GPU SVM structure + * @notifier: Pointer to the GPU SVM notifier structure + * @fault_addr: Fault address + * @chunk_size: Chunk size + * @migrate_devmem: Flag indicating whether to migrate device memory + * + * This function allocates and initializes the GPU SVM range structure. + * + * Return: Pointer to the allocated GPU SVM range on success, ERR_PTR() on failure. + */ +static struct drm_gpusvm_range * +drm_gpusvm_range_alloc(struct drm_gpusvm *gpusvm, + struct drm_gpusvm_notifier *notifier, + unsigned long fault_addr, unsigned long chunk_size, + bool migrate_devmem) +{ + struct drm_gpusvm_range *range; + + if (gpusvm->ops->range_alloc) + range = gpusvm->ops->range_alloc(gpusvm); + else + range = kzalloc(sizeof(*range), GFP_KERNEL); + + if (!range) + return ERR_PTR(-ENOMEM); + + kref_init(&range->refcount); + range->gpusvm = gpusvm; + range->notifier = notifier; + range->itree.start = ALIGN_DOWN(fault_addr, chunk_size); + range->itree.last = ALIGN(fault_addr + 1, chunk_size) - 1; + INIT_LIST_HEAD(&range->entry); + range->notifier_seq = LONG_MAX; + range->flags.migrate_devmem = migrate_devmem ? 1 : 0; + + return range; +} + +/** + * drm_gpusvm_check_pages() - Check pages + * @gpusvm: Pointer to the GPU SVM structure + * @notifier: Pointer to the GPU SVM notifier structure + * @start: Start address + * @end: End address + * + * Check if pages between start and end have been faulted in on the CPU. Use to + * prevent migration of pages without CPU backing store. + * + * Return: True if pages have been faulted into CPU, False otherwise + */ +static bool drm_gpusvm_check_pages(struct drm_gpusvm *gpusvm, + struct drm_gpusvm_notifier *notifier, + unsigned long start, unsigned long end) +{ + struct hmm_range hmm_range = { + .default_flags = 0, + .notifier = ¬ifier->notifier, + .start = start, + .end = end, + .dev_private_owner = gpusvm->device_private_page_owner, + }; + unsigned long timeout = + jiffies + msecs_to_jiffies(HMM_RANGE_DEFAULT_TIMEOUT); + unsigned long *pfns; + unsigned long npages = npages_in_range(start, end); + int err, i; + + mmap_assert_locked(gpusvm->mm); + + pfns = kvmalloc_array(npages, sizeof(*pfns), GFP_KERNEL); + if (!pfns) + return false; + + hmm_range.notifier_seq = mmu_interval_read_begin(¬ifier->notifier); + hmm_range.hmm_pfns = pfns; + + while (true) { + err = hmm_range_fault(&hmm_range); + if (err == -EBUSY) { + if (time_after(jiffies, timeout)) + break; + + hmm_range.notifier_seq = + mmu_interval_read_begin(¬ifier->notifier); + continue; + } + break; + } + if (err) + goto err_free; + + for (i = 0; i < npages;) { + if (!(pfns[i] & HMM_PFN_VALID)) { + err = -EFAULT; + goto err_free; + } + i += 0x1 << hmm_pfn_to_map_order(pfns[i]); + } + +err_free: + kvfree(pfns); + return err ? false : true; +} + +/** + * drm_gpusvm_range_chunk_size() - Determine chunk size for GPU SVM range + * @gpusvm: Pointer to the GPU SVM structure + * @notifier: Pointer to the GPU SVM notifier structure + * @vas: Pointer to the virtual memory area structure + * @fault_addr: Fault address + * @gpuva_start: Start address of GPUVA which mirrors CPU + * @gpuva_end: End address of GPUVA which mirrors CPU + * @check_pages_threshold: Check CPU pages for present threshold + * + * This function determines the chunk size for the GPU SVM range based on the + * fault address, GPU SVM chunk sizes, existing GPU SVM ranges, and the virtual + * memory area boundaries. + * + * Return: Chunk size on success, LONG_MAX on failure. + */ +static unsigned long +drm_gpusvm_range_chunk_size(struct drm_gpusvm *gpusvm, + struct drm_gpusvm_notifier *notifier, + struct vm_area_struct *vas, + unsigned long fault_addr, + unsigned long gpuva_start, + unsigned long gpuva_end, + unsigned long check_pages_threshold) +{ + unsigned long start, end; + int i = 0; + +retry: + for (; i < gpusvm->num_chunks; ++i) { + start = ALIGN_DOWN(fault_addr, gpusvm->chunk_sizes[i]); + end = ALIGN(fault_addr + 1, gpusvm->chunk_sizes[i]); + + if (start >= vas->vm_start && end <= vas->vm_end && + start >= drm_gpusvm_notifier_start(notifier) && + end <= drm_gpusvm_notifier_end(notifier) && + start >= gpuva_start && end <= gpuva_end) + break; + } + + if (i == gpusvm->num_chunks) + return LONG_MAX; + + /* + * If allocation more than page, ensure not to overlap with existing + * ranges. + */ + if (end - start != SZ_4K) { + struct drm_gpusvm_range *range; + + range = drm_gpusvm_range_find(notifier, start, end); + if (range) { + ++i; + goto retry; + } + + /* + * XXX: Only create range on pages CPU has faulted in. Without + * this check, or prefault, on BMG 'xe_exec_system_allocator --r + * process-many-malloc' fails. In the failure case, each process + * mallocs 16k but the CPU VMA is ~128k which results in 64k SVM + * ranges. When migrating the SVM ranges, some processes fail in + * drm_pagemap_migrate_to_devmem with 'migrate.cpages != npages' + * and then upon drm_gpusvm_range_get_pages device pages from + * other processes are collected + faulted in which creates all + * sorts of problems. Unsure exactly how this happening, also + * problem goes away if 'xe_exec_system_allocator --r + * process-many-malloc' mallocs at least 64k at a time. + */ + if (end - start <= check_pages_threshold && + !drm_gpusvm_check_pages(gpusvm, notifier, start, end)) { + ++i; + goto retry; + } + } + + return end - start; +} + +#ifdef CONFIG_LOCKDEP +/** + * drm_gpusvm_driver_lock_held() - Assert GPU SVM driver lock is held + * @gpusvm: Pointer to the GPU SVM structure. + * + * Ensure driver lock is held. + */ +static void drm_gpusvm_driver_lock_held(struct drm_gpusvm *gpusvm) +{ + if ((gpusvm)->lock_dep_map) + lockdep_assert(lock_is_held_type((gpusvm)->lock_dep_map, 0)); +} +#else +static void drm_gpusvm_driver_lock_held(struct drm_gpusvm *gpusvm) +{ +} +#endif + +/** + * drm_gpusvm_find_vma_start() - Find start address for first VMA in range + * @gpusvm: Pointer to the GPU SVM structure + * @start: The inclusive start user address. + * @end: The exclusive end user address. + * + * Returns: The start address of first VMA within the provided range, + * ULONG_MAX otherwise. Assumes start_addr < end_addr. + */ +unsigned long +drm_gpusvm_find_vma_start(struct drm_gpusvm *gpusvm, + unsigned long start, + unsigned long end) +{ + struct mm_struct *mm = gpusvm->mm; + struct vm_area_struct *vma; + unsigned long addr = ULONG_MAX; + + if (!mmget_not_zero(mm)) + return addr; + + mmap_read_lock(mm); + + vma = find_vma_intersection(mm, start, end); + if (vma) + addr = vma->vm_start; + + mmap_read_unlock(mm); + mmput(mm); + + return addr; +} +EXPORT_SYMBOL_GPL(drm_gpusvm_find_vma_start); + +/** + * drm_gpusvm_range_find_or_insert() - Find or insert GPU SVM range + * @gpusvm: Pointer to the GPU SVM structure + * @fault_addr: Fault address + * @gpuva_start: Start address of GPUVA which mirrors CPU + * @gpuva_end: End address of GPUVA which mirrors CPU + * @ctx: GPU SVM context + * + * This function finds or inserts a newly allocated a GPU SVM range based on the + * fault address. Caller must hold a lock to protect range lookup and insertion. + * + * Return: Pointer to the GPU SVM range on success, ERR_PTR() on failure. + */ +struct drm_gpusvm_range * +drm_gpusvm_range_find_or_insert(struct drm_gpusvm *gpusvm, + unsigned long fault_addr, + unsigned long gpuva_start, + unsigned long gpuva_end, + const struct drm_gpusvm_ctx *ctx) +{ + struct drm_gpusvm_notifier *notifier; + struct drm_gpusvm_range *range; + struct mm_struct *mm = gpusvm->mm; + struct vm_area_struct *vas; + bool notifier_alloc = false; + unsigned long chunk_size; + int err; + bool migrate_devmem; + + drm_gpusvm_driver_lock_held(gpusvm); + + if (fault_addr < gpusvm->mm_start || + fault_addr > gpusvm->mm_start + gpusvm->mm_range) + return ERR_PTR(-EINVAL); + + if (!mmget_not_zero(mm)) + return ERR_PTR(-EFAULT); + + notifier = drm_gpusvm_notifier_find(gpusvm, fault_addr); + if (!notifier) { + notifier = drm_gpusvm_notifier_alloc(gpusvm, fault_addr); + if (IS_ERR(notifier)) { + err = PTR_ERR(notifier); + goto err_mmunlock; + } + notifier_alloc = true; + err = mmu_interval_notifier_insert(¬ifier->notifier, + mm, + drm_gpusvm_notifier_start(notifier), + drm_gpusvm_notifier_size(notifier), + &drm_gpusvm_notifier_ops); + if (err) + goto err_notifier; + } + + mmap_read_lock(mm); + + vas = vma_lookup(mm, fault_addr); + if (!vas) { + err = -ENOENT; + goto err_notifier_remove; + } + + if (!ctx->read_only && !(vas->vm_flags & VM_WRITE)) { + err = -EPERM; + goto err_notifier_remove; + } + + range = drm_gpusvm_range_find(notifier, fault_addr, fault_addr + 1); + if (range) + goto out_mmunlock; + /* + * XXX: Short-circuiting migration based on migrate_vma_* current + * limitations. If/when migrate_vma_* add more support, this logic will + * have to change. + */ + migrate_devmem = ctx->devmem_possible && + vma_is_anonymous(vas) && !is_vm_hugetlb_page(vas); + + chunk_size = drm_gpusvm_range_chunk_size(gpusvm, notifier, vas, + fault_addr, gpuva_start, + gpuva_end, + ctx->check_pages_threshold); + if (chunk_size == LONG_MAX) { + err = -EINVAL; + goto err_notifier_remove; + } + + range = drm_gpusvm_range_alloc(gpusvm, notifier, fault_addr, chunk_size, + migrate_devmem); + if (IS_ERR(range)) { + err = PTR_ERR(range); + goto err_notifier_remove; + } + + drm_gpusvm_range_insert(notifier, range); + if (notifier_alloc) + drm_gpusvm_notifier_insert(gpusvm, notifier); + +out_mmunlock: + mmap_read_unlock(mm); + mmput(mm); + + return range; + +err_notifier_remove: + mmap_read_unlock(mm); + if (notifier_alloc) + mmu_interval_notifier_remove(¬ifier->notifier); +err_notifier: + if (notifier_alloc) + drm_gpusvm_notifier_free(gpusvm, notifier); +err_mmunlock: + mmput(mm); + return ERR_PTR(err); +} +EXPORT_SYMBOL_GPL(drm_gpusvm_range_find_or_insert); + +/** + * __drm_gpusvm_range_unmap_pages() - Unmap pages associated with a GPU SVM range (internal) + * @gpusvm: Pointer to the GPU SVM structure + * @range: Pointer to the GPU SVM range structure + * @npages: Number of pages to unmap + * + * This function unmap pages associated with a GPU SVM range. Assumes and + * asserts correct locking is in place when called. + */ +static void __drm_gpusvm_range_unmap_pages(struct drm_gpusvm *gpusvm, + struct drm_gpusvm_range *range, + unsigned long npages) +{ + unsigned long i, j; + struct drm_pagemap *dpagemap = range->dpagemap; + struct device *dev = gpusvm->drm->dev; + + lockdep_assert_held(&gpusvm->notifier_lock); + + if (range->flags.has_dma_mapping) { + struct drm_gpusvm_range_flags flags = { + .__flags = range->flags.__flags, + }; + + for (i = 0, j = 0; i < npages; j++) { + struct drm_pagemap_device_addr *addr = &range->dma_addr[j]; + + if (addr->proto == DRM_INTERCONNECT_SYSTEM) + dma_unmap_page(dev, + addr->addr, + PAGE_SIZE << addr->order, + addr->dir); + else if (dpagemap && dpagemap->ops->device_unmap) + dpagemap->ops->device_unmap(dpagemap, + dev, *addr); + i += 1 << addr->order; + } + + /* WRITE_ONCE pairs with READ_ONCE for opportunistic checks */ + flags.has_devmem_pages = false; + flags.has_dma_mapping = false; + WRITE_ONCE(range->flags.__flags, flags.__flags); + + range->dpagemap = NULL; + } +} + +/** + * drm_gpusvm_range_free_pages() - Free pages associated with a GPU SVM range + * @gpusvm: Pointer to the GPU SVM structure + * @range: Pointer to the GPU SVM range structure + * + * This function frees the dma address array associated with a GPU SVM range. + */ +static void drm_gpusvm_range_free_pages(struct drm_gpusvm *gpusvm, + struct drm_gpusvm_range *range) +{ + lockdep_assert_held(&gpusvm->notifier_lock); + + if (range->dma_addr) { + kvfree(range->dma_addr); + range->dma_addr = NULL; + } +} + +/** + * drm_gpusvm_range_remove() - Remove GPU SVM range + * @gpusvm: Pointer to the GPU SVM structure + * @range: Pointer to the GPU SVM range to be removed + * + * This function removes the specified GPU SVM range and also removes the parent + * GPU SVM notifier if no more ranges remain in the notifier. The caller must + * hold a lock to protect range and notifier removal. + */ +void drm_gpusvm_range_remove(struct drm_gpusvm *gpusvm, + struct drm_gpusvm_range *range) +{ + unsigned long npages = npages_in_range(drm_gpusvm_range_start(range), + drm_gpusvm_range_end(range)); + struct drm_gpusvm_notifier *notifier; + + drm_gpusvm_driver_lock_held(gpusvm); + + notifier = drm_gpusvm_notifier_find(gpusvm, + drm_gpusvm_range_start(range)); + if (WARN_ON_ONCE(!notifier)) + return; + + drm_gpusvm_notifier_lock(gpusvm); + __drm_gpusvm_range_unmap_pages(gpusvm, range, npages); + drm_gpusvm_range_free_pages(gpusvm, range); + __drm_gpusvm_range_remove(notifier, range); + drm_gpusvm_notifier_unlock(gpusvm); + + drm_gpusvm_range_put(range); + + if (RB_EMPTY_ROOT(¬ifier->root.rb_root)) { + if (!notifier->flags.removed) + mmu_interval_notifier_remove(¬ifier->notifier); + drm_gpusvm_notifier_remove(gpusvm, notifier); + drm_gpusvm_notifier_free(gpusvm, notifier); + } +} +EXPORT_SYMBOL_GPL(drm_gpusvm_range_remove); + +/** + * drm_gpusvm_range_get() - Get a reference to GPU SVM range + * @range: Pointer to the GPU SVM range + * + * This function increments the reference count of the specified GPU SVM range. + * + * Return: Pointer to the GPU SVM range. + */ +struct drm_gpusvm_range * +drm_gpusvm_range_get(struct drm_gpusvm_range *range) +{ + kref_get(&range->refcount); + + return range; +} +EXPORT_SYMBOL_GPL(drm_gpusvm_range_get); + +/** + * drm_gpusvm_range_destroy() - Destroy GPU SVM range + * @refcount: Pointer to the reference counter embedded in the GPU SVM range + * + * This function destroys the specified GPU SVM range when its reference count + * reaches zero. If a custom range-free function is provided, it is invoked to + * free the range; otherwise, the range is deallocated using kfree(). + */ +static void drm_gpusvm_range_destroy(struct kref *refcount) +{ + struct drm_gpusvm_range *range = + container_of(refcount, struct drm_gpusvm_range, refcount); + struct drm_gpusvm *gpusvm = range->gpusvm; + + if (gpusvm->ops->range_free) + gpusvm->ops->range_free(range); + else + kfree(range); +} + +/** + * drm_gpusvm_range_put() - Put a reference to GPU SVM range + * @range: Pointer to the GPU SVM range + * + * This function decrements the reference count of the specified GPU SVM range + * and frees it when the count reaches zero. + */ +void drm_gpusvm_range_put(struct drm_gpusvm_range *range) +{ + kref_put(&range->refcount, drm_gpusvm_range_destroy); +} +EXPORT_SYMBOL_GPL(drm_gpusvm_range_put); + +/** + * drm_gpusvm_range_pages_valid() - GPU SVM range pages valid + * @gpusvm: Pointer to the GPU SVM structure + * @range: Pointer to the GPU SVM range structure + * + * This function determines if a GPU SVM range pages are valid. Expected be + * called holding gpusvm->notifier_lock and as the last step before committing a + * GPU binding. This is akin to a notifier seqno check in the HMM documentation + * but due to wider notifiers (i.e., notifiers which span multiple ranges) this + * function is required for finer grained checking (i.e., per range) if pages + * are valid. + * + * Return: True if GPU SVM range has valid pages, False otherwise + */ +bool drm_gpusvm_range_pages_valid(struct drm_gpusvm *gpusvm, + struct drm_gpusvm_range *range) +{ + lockdep_assert_held(&gpusvm->notifier_lock); + + return range->flags.has_devmem_pages || range->flags.has_dma_mapping; +} +EXPORT_SYMBOL_GPL(drm_gpusvm_range_pages_valid); + +/** + * drm_gpusvm_range_pages_valid_unlocked() - GPU SVM range pages valid unlocked + * @gpusvm: Pointer to the GPU SVM structure + * @range: Pointer to the GPU SVM range structure + * + * This function determines if a GPU SVM range pages are valid. Expected be + * called without holding gpusvm->notifier_lock. + * + * Return: True if GPU SVM range has valid pages, False otherwise + */ +static bool +drm_gpusvm_range_pages_valid_unlocked(struct drm_gpusvm *gpusvm, + struct drm_gpusvm_range *range) +{ + bool pages_valid; + + if (!range->dma_addr) + return false; + + drm_gpusvm_notifier_lock(gpusvm); + pages_valid = drm_gpusvm_range_pages_valid(gpusvm, range); + if (!pages_valid) + drm_gpusvm_range_free_pages(gpusvm, range); + drm_gpusvm_notifier_unlock(gpusvm); + + return pages_valid; +} + +/** + * drm_gpusvm_range_get_pages() - Get pages for a GPU SVM range + * @gpusvm: Pointer to the GPU SVM structure + * @range: Pointer to the GPU SVM range structure + * @ctx: GPU SVM context + * + * This function gets pages for a GPU SVM range and ensures they are mapped for + * DMA access. + * + * Return: 0 on success, negative error code on failure. + */ +int drm_gpusvm_range_get_pages(struct drm_gpusvm *gpusvm, + struct drm_gpusvm_range *range, + const struct drm_gpusvm_ctx *ctx) +{ + struct mmu_interval_notifier *notifier = &range->notifier->notifier; + struct hmm_range hmm_range = { + .default_flags = HMM_PFN_REQ_FAULT | (ctx->read_only ? 0 : + HMM_PFN_REQ_WRITE), + .notifier = notifier, + .start = drm_gpusvm_range_start(range), + .end = drm_gpusvm_range_end(range), + .dev_private_owner = gpusvm->device_private_page_owner, + }; + struct mm_struct *mm = gpusvm->mm; + void *zdd; + unsigned long timeout = + jiffies + msecs_to_jiffies(HMM_RANGE_DEFAULT_TIMEOUT); + unsigned long i, j; + unsigned long npages = npages_in_range(drm_gpusvm_range_start(range), + drm_gpusvm_range_end(range)); + unsigned long num_dma_mapped; + unsigned int order = 0; + unsigned long *pfns; + int err = 0; + struct dev_pagemap *pagemap; + struct drm_pagemap *dpagemap; + struct drm_gpusvm_range_flags flags; + +retry: + hmm_range.notifier_seq = mmu_interval_read_begin(notifier); + if (drm_gpusvm_range_pages_valid_unlocked(gpusvm, range)) + goto set_seqno; + + pfns = kvmalloc_array(npages, sizeof(*pfns), GFP_KERNEL); + if (!pfns) + return -ENOMEM; + + if (!mmget_not_zero(mm)) { + err = -EFAULT; + goto err_free; + } + + hmm_range.hmm_pfns = pfns; + while (true) { + mmap_read_lock(mm); + err = hmm_range_fault(&hmm_range); + mmap_read_unlock(mm); + + if (err == -EBUSY) { + if (time_after(jiffies, timeout)) + break; + + hmm_range.notifier_seq = + mmu_interval_read_begin(notifier); + continue; + } + break; + } + mmput(mm); + if (err) + goto err_free; + +map_pages: + /* + * Perform all dma mappings under the notifier lock to not + * access freed pages. A notifier will either block on + * the notifier lock or unmap dma. + */ + drm_gpusvm_notifier_lock(gpusvm); + + flags.__flags = range->flags.__flags; + if (flags.unmapped) { + drm_gpusvm_notifier_unlock(gpusvm); + err = -EFAULT; + goto err_free; + } + + if (mmu_interval_read_retry(notifier, hmm_range.notifier_seq)) { + drm_gpusvm_notifier_unlock(gpusvm); + kvfree(pfns); + goto retry; + } + + if (!range->dma_addr) { + /* Unlock and restart mapping to allocate memory. */ + drm_gpusvm_notifier_unlock(gpusvm); + range->dma_addr = kvmalloc_array(npages, + sizeof(*range->dma_addr), + GFP_KERNEL); + if (!range->dma_addr) { + err = -ENOMEM; + goto err_free; + } + goto map_pages; + } + + zdd = NULL; + pagemap = NULL; + num_dma_mapped = 0; + for (i = 0, j = 0; i < npages; ++j) { + struct page *page = hmm_pfn_to_page(pfns[i]); + + order = hmm_pfn_to_map_order(pfns[i]); + if (is_device_private_page(page) || + is_device_coherent_page(page)) { + if (zdd != page->zone_device_data && i > 0) { + err = -EOPNOTSUPP; + goto err_unmap; + } + zdd = page->zone_device_data; + if (pagemap != page_pgmap(page)) { + if (i > 0) { + err = -EOPNOTSUPP; + goto err_unmap; + } + + pagemap = page_pgmap(page); + dpagemap = drm_pagemap_page_to_dpagemap(page); + if (drm_WARN_ON(gpusvm->drm, !dpagemap)) { + /* + * Raced. This is not supposed to happen + * since hmm_range_fault() should've migrated + * this page to system. + */ + err = -EAGAIN; + goto err_unmap; + } + } + range->dma_addr[j] = + dpagemap->ops->device_map(dpagemap, + gpusvm->drm->dev, + page, order, + DMA_BIDIRECTIONAL); + if (dma_mapping_error(gpusvm->drm->dev, + range->dma_addr[j].addr)) { + err = -EFAULT; + goto err_unmap; + } + } else { + dma_addr_t addr; + + if (is_zone_device_page(page) || pagemap) { + err = -EOPNOTSUPP; + goto err_unmap; + } + + if (ctx->devmem_only) { + err = -EFAULT; + goto err_unmap; + } + + addr = dma_map_page(gpusvm->drm->dev, + page, 0, + PAGE_SIZE << order, + DMA_BIDIRECTIONAL); + if (dma_mapping_error(gpusvm->drm->dev, addr)) { + err = -EFAULT; + goto err_unmap; + } + + range->dma_addr[j] = drm_pagemap_device_addr_encode + (addr, DRM_INTERCONNECT_SYSTEM, order, + DMA_BIDIRECTIONAL); + } + i += 1 << order; + num_dma_mapped = i; + flags.has_dma_mapping = true; + } + + if (pagemap) { + flags.has_devmem_pages = true; + range->dpagemap = dpagemap; + } + + /* WRITE_ONCE pairs with READ_ONCE for opportunistic checks */ + WRITE_ONCE(range->flags.__flags, flags.__flags); + + drm_gpusvm_notifier_unlock(gpusvm); + kvfree(pfns); +set_seqno: + range->notifier_seq = hmm_range.notifier_seq; + + return 0; + +err_unmap: + __drm_gpusvm_range_unmap_pages(gpusvm, range, num_dma_mapped); + drm_gpusvm_notifier_unlock(gpusvm); +err_free: + kvfree(pfns); + if (err == -EAGAIN) + goto retry; + return err; +} +EXPORT_SYMBOL_GPL(drm_gpusvm_range_get_pages); + +/** + * drm_gpusvm_range_unmap_pages() - Unmap pages associated with a GPU SVM range + * drm_gpusvm_range_evict() - Evict GPU SVM range + * @gpusvm: Pointer to the GPU SVM structure + * @range: Pointer to the GPU SVM range structure + * @ctx: GPU SVM context + * + * This function unmaps pages associated with a GPU SVM range. If @in_notifier + * is set, it is assumed that gpusvm->notifier_lock is held in write mode; if it + * is clear, it acquires gpusvm->notifier_lock in read mode. Must be called on + * each GPU SVM range attached to notifier in gpusvm->ops->invalidate for IOMMU + * security model. + */ +void drm_gpusvm_range_unmap_pages(struct drm_gpusvm *gpusvm, + struct drm_gpusvm_range *range, + const struct drm_gpusvm_ctx *ctx) +{ + unsigned long npages = npages_in_range(drm_gpusvm_range_start(range), + drm_gpusvm_range_end(range)); + + if (ctx->in_notifier) + lockdep_assert_held_write(&gpusvm->notifier_lock); + else + drm_gpusvm_notifier_lock(gpusvm); + + __drm_gpusvm_range_unmap_pages(gpusvm, range, npages); + + if (!ctx->in_notifier) + drm_gpusvm_notifier_unlock(gpusvm); +} +EXPORT_SYMBOL_GPL(drm_gpusvm_range_unmap_pages); + +/** + * drm_gpusvm_range_evict() - Evict GPU SVM range + * @gpusvm: Pointer to the GPU SVM structure + * @range: Pointer to the GPU SVM range to be removed + * + * This function evicts the specified GPU SVM range. + * + * Return: 0 on success, a negative error code on failure. + */ +int drm_gpusvm_range_evict(struct drm_gpusvm *gpusvm, + struct drm_gpusvm_range *range) +{ + struct mmu_interval_notifier *notifier = &range->notifier->notifier; + struct hmm_range hmm_range = { + .default_flags = HMM_PFN_REQ_FAULT, + .notifier = notifier, + .start = drm_gpusvm_range_start(range), + .end = drm_gpusvm_range_end(range), + .dev_private_owner = NULL, + }; + unsigned long timeout = + jiffies + msecs_to_jiffies(HMM_RANGE_DEFAULT_TIMEOUT); + unsigned long *pfns; + unsigned long npages = npages_in_range(drm_gpusvm_range_start(range), + drm_gpusvm_range_end(range)); + int err = 0; + struct mm_struct *mm = gpusvm->mm; + + if (!mmget_not_zero(mm)) + return -EFAULT; + + pfns = kvmalloc_array(npages, sizeof(*pfns), GFP_KERNEL); + if (!pfns) + return -ENOMEM; + + hmm_range.hmm_pfns = pfns; + while (!time_after(jiffies, timeout)) { + hmm_range.notifier_seq = mmu_interval_read_begin(notifier); + if (time_after(jiffies, timeout)) { + err = -ETIME; + break; + } + + mmap_read_lock(mm); + err = hmm_range_fault(&hmm_range); + mmap_read_unlock(mm); + if (err != -EBUSY) + break; + } + + kvfree(pfns); + mmput(mm); + + return err; +} +EXPORT_SYMBOL_GPL(drm_gpusvm_range_evict); + +/** + * drm_gpusvm_has_mapping() - Check if GPU SVM has mapping for the given address range + * @gpusvm: Pointer to the GPU SVM structure. + * @start: Start address + * @end: End address + * + * Return: True if GPU SVM has mapping, False otherwise + */ +bool drm_gpusvm_has_mapping(struct drm_gpusvm *gpusvm, unsigned long start, + unsigned long end) +{ + struct drm_gpusvm_notifier *notifier; + + drm_gpusvm_for_each_notifier(notifier, gpusvm, start, end) { + struct drm_gpusvm_range *range = NULL; + + drm_gpusvm_for_each_range(range, notifier, start, end) + return true; + } + + return false; +} +EXPORT_SYMBOL_GPL(drm_gpusvm_has_mapping); + +/** + * drm_gpusvm_range_set_unmapped() - Mark a GPU SVM range as unmapped + * @range: Pointer to the GPU SVM range structure. + * @mmu_range: Pointer to the MMU notifier range structure. + * + * This function marks a GPU SVM range as unmapped and sets the partial_unmap flag + * if the range partially falls within the provided MMU notifier range. + */ +void drm_gpusvm_range_set_unmapped(struct drm_gpusvm_range *range, + const struct mmu_notifier_range *mmu_range) +{ + lockdep_assert_held_write(&range->gpusvm->notifier_lock); + + range->flags.unmapped = true; + if (drm_gpusvm_range_start(range) < mmu_range->start || + drm_gpusvm_range_end(range) > mmu_range->end) + range->flags.partial_unmap = true; +} +EXPORT_SYMBOL_GPL(drm_gpusvm_range_set_unmapped); + +MODULE_DESCRIPTION("DRM GPUSVM"); +MODULE_LICENSE("GPL"); |