1 files changed, 509 insertions, 0 deletions
diff --git a/include/drm/drm_gpusvm.h b/include/drm/drm_gpusvm.h
new file mode 100644
index 000000000000..df120b4d1f83
--- /dev/null
+++ b/include/drm/drm_gpusvm.h
@@ -0,0 +1,509 @@
+/* SPDX-License-Identifier: GPL-2.0-only OR MIT */
+/*
+ * Copyright © 2024 Intel Corporation
+ */
+
+#ifndef __DRM_GPUSVM_H__
+#define __DRM_GPUSVM_H__
+
+#include <linux/kref.h>
+#include <linux/interval_tree.h>
+#include <linux/mmu_notifier.h>
+
+struct dev_pagemap_ops;
+struct drm_device;
+struct drm_gpusvm;
+struct drm_gpusvm_notifier;
+struct drm_gpusvm_ops;
+struct drm_gpusvm_range;
+struct drm_gpusvm_devmem;
+struct drm_pagemap;
+struct drm_pagemap_device_addr;
+
+/**
+ * struct drm_gpusvm_devmem_ops - Operations structure for GPU SVM device memory
+ *
+ * This structure defines the operations for GPU Shared Virtual Memory (SVM)
+ * device memory. These operations are provided by the GPU driver to manage device memory
+ * allocations and perform operations such as migration between device memory and system
+ * RAM.
+ */
+struct drm_gpusvm_devmem_ops {
+	/**
+	 * @devmem_release: Release device memory allocation (optional)
+	 * @devmem_allocation: device memory allocation
+	 *
+	 * Release device memory allocation and drop a reference to device
+	 * memory allocation.
+	 */
+	void (*devmem_release)(struct drm_gpusvm_devmem *devmem_allocation);
+
+	/**
+	 * @populate_devmem_pfn: Populate device memory PFN (required for migration)
+	 * @devmem_allocation: device memory allocation
+	 * @npages: Number of pages to populate
+	 * @pfn: Array of page frame numbers to populate
+	 *
+	 * Populate device memory page frame numbers (PFN).
+	 *
+	 * Return: 0 on success, a negative error code on failure.
+	 */
+	int (*populate_devmem_pfn)(struct drm_gpusvm_devmem *devmem_allocation,
+				   unsigned long npages, unsigned long *pfn);
+
+	/**
+	 * @copy_to_devmem: Copy to device memory (required for migration)
+	 * @pages: Pointer to array of device memory pages (destination)
+	 * @dma_addr: Pointer to array of DMA addresses (source)
+	 * @npages: Number of pages to copy
+	 *
+	 * Copy pages to device memory.
+	 *
+	 * Return: 0 on success, a negative error code on failure.
+	 */
+	int (*copy_to_devmem)(struct page **pages,
+			      dma_addr_t *dma_addr,
+			      unsigned long npages);
+
+	/**
+	 * @copy_to_ram: Copy to system RAM (required for migration)
+	 * @pages: Pointer to array of device memory pages (source)
+	 * @dma_addr: Pointer to array of DMA addresses (destination)
+	 * @npages: Number of pages to copy
+	 *
+	 * Copy pages to system RAM.
+	 *
+	 * Return: 0 on success, a negative error code on failure.
+	 */
+	int (*copy_to_ram)(struct page **pages,
+			   dma_addr_t *dma_addr,
+			   unsigned long npages);
+};
+
+/**
+ * struct drm_gpusvm_devmem - Structure representing a GPU SVM device memory allocation
+ *
+ * @dev: Pointer to the device structure which device memory allocation belongs to
+ * @mm: Pointer to the mm_struct for the address space
+ * @detached: device memory allocations is detached from device pages
+ * @ops: Pointer to the operations structure for GPU SVM device memory
+ * @dpagemap: The struct drm_pagemap of the pages this allocation belongs to.
+ * @size: Size of device memory allocation
+ */
+struct drm_gpusvm_devmem {
+	struct device *dev;
+	struct mm_struct *mm;
+	struct completion detached;
+	const struct drm_gpusvm_devmem_ops *ops;
+	struct drm_pagemap *dpagemap;
+	size_t size;
+};
+
+/**
+ * struct drm_gpusvm_ops - Operations structure for GPU SVM
+ *
+ * This structure defines the operations for GPU Shared Virtual Memory (SVM).
+ * These operations are provided by the GPU driver to manage SVM ranges and
+ * notifiers.
+ */
+struct drm_gpusvm_ops {
+	/**
+	 * @notifier_alloc: Allocate a GPU SVM notifier (optional)
+	 *
+	 * Allocate a GPU SVM notifier.
+	 *
+	 * Return: Pointer to the allocated GPU SVM notifier on success, NULL on failure.
+	 */
+	struct drm_gpusvm_notifier *(*notifier_alloc)(void);
+
+	/**
+	 * @notifier_free: Free a GPU SVM notifier (optional)
+	 * @notifier: Pointer to the GPU SVM notifier to be freed
+	 *
+	 * Free a GPU SVM notifier.
+	 */
+	void (*notifier_free)(struct drm_gpusvm_notifier *notifier);
+
+	/**
+	 * @range_alloc: Allocate a GPU SVM range (optional)
+	 * @gpusvm: Pointer to the GPU SVM
+	 *
+	 * Allocate a GPU SVM range.
+	 *
+	 * Return: Pointer to the allocated GPU SVM range on success, NULL on failure.
+	 */
+	struct drm_gpusvm_range *(*range_alloc)(struct drm_gpusvm *gpusvm);
+
+	/**
+	 * @range_free: Free a GPU SVM range (optional)
+	 * @range: Pointer to the GPU SVM range to be freed
+	 *
+	 * Free a GPU SVM range.
+	 */
+	void (*range_free)(struct drm_gpusvm_range *range);
+
+	/**
+	 * @invalidate: Invalidate GPU SVM notifier (required)
+	 * @gpusvm: Pointer to the GPU SVM
+	 * @notifier: Pointer to the GPU SVM notifier
+	 * @mmu_range: Pointer to the mmu_notifier_range structure
+	 *
+	 * Invalidate the GPU page tables. It can safely walk the notifier range
+	 * RB tree/list in this function. Called while holding the notifier lock.
+	 */
+	void (*invalidate)(struct drm_gpusvm *gpusvm,
+			   struct drm_gpusvm_notifier *notifier,
+			   const struct mmu_notifier_range *mmu_range);
+};
+
+/**
+ * struct drm_gpusvm_notifier - Structure representing a GPU SVM notifier
+ *
+ * @gpusvm: Pointer to the GPU SVM structure
+ * @notifier: MMU interval notifier
+ * @itree: Interval tree node for the notifier (inserted in GPU SVM)
+ * @entry: List entry to fast interval tree traversal
+ * @root: Cached root node of the RB tree containing ranges
+ * @range_list: List head containing of ranges in the same order they appear in
+ *              interval tree. This is useful to keep iterating ranges while
+ *              doing modifications to RB tree.
+ * @flags: Flags for notifier
+ * @flags.removed: Flag indicating whether the MMU interval notifier has been
+ *                 removed
+ *
+ * This structure represents a GPU SVM notifier.
+ */
+struct drm_gpusvm_notifier {
+	struct drm_gpusvm *gpusvm;
+	struct mmu_interval_notifier notifier;
+	struct interval_tree_node itree;
+	struct list_head entry;
+	struct rb_root_cached root;
+	struct list_head range_list;
+	struct {
+		u32 removed : 1;
+	} flags;
+};
+
+/**
+ * struct drm_gpusvm_range - Structure representing a GPU SVM range
+ *
+ * @gpusvm: Pointer to the GPU SVM structure
+ * @notifier: Pointer to the GPU SVM notifier
+ * @refcount: Reference count for the range
+ * @itree: Interval tree node for the range (inserted in GPU SVM notifier)
+ * @entry: List entry to fast interval tree traversal
+ * @notifier_seq: Notifier sequence number of the range's pages
+ * @dma_addr: Device address array
+ * @dpagemap: The struct drm_pagemap of the device pages we're dma-mapping.
+ *            Note this is assuming only one drm_pagemap per range is allowed.
+ * @flags: Flags for range
+ * @flags.migrate_devmem: Flag indicating whether the range can be migrated to device memory
+ * @flags.unmapped: Flag indicating if the range has been unmapped
+ * @flags.partial_unmap: Flag indicating if the range has been partially unmapped
+ * @flags.has_devmem_pages: Flag indicating if the range has devmem pages
+ * @flags.has_dma_mapping: Flag indicating if the range has a DMA mapping
+ *
+ * This structure represents a GPU SVM range used for tracking memory ranges
+ * mapped in a DRM device.
+ */
+struct drm_gpusvm_range {
+	struct drm_gpusvm *gpusvm;
+	struct drm_gpusvm_notifier *notifier;
+	struct kref refcount;
+	struct interval_tree_node itree;
+	struct list_head entry;
+	unsigned long notifier_seq;
+	struct drm_pagemap_device_addr *dma_addr;
+	struct drm_pagemap *dpagemap;
+	struct {
+		/* All flags below must be set upon creation */
+		u16 migrate_devmem : 1;
+		/* All flags below must be set / cleared under notifier lock */
+		u16 unmapped : 1;
+		u16 partial_unmap : 1;
+		u16 has_devmem_pages : 1;
+		u16 has_dma_mapping : 1;
+	} flags;
+};
+
+/**
+ * struct drm_gpusvm - 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.
+ * @num_chunks: Number of chunks
+ * @notifier_lock: Read-write semaphore for protecting notifier operations
+ * @root: Cached root node of the Red-Black tree containing GPU SVM notifiers
+ * @notifier_list: list head containing of notifiers in the same order they
+ *                 appear in interval tree. This is useful to keep iterating
+ *                 notifiers while doing modifications to RB tree.
+ *
+ * This structure represents a GPU SVM (Shared Virtual Memory) used for tracking
+ * memory ranges mapped in a DRM (Direct Rendering Manager) device.
+ *
+ * No reference counting is provided, as this is expected to be embedded in the
+ * driver VM structure along with the struct drm_gpuvm, which handles reference
+ * counting.
+ */
+struct drm_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;
+	struct rw_semaphore notifier_lock;
+	struct rb_root_cached root;
+	struct list_head notifier_list;
+#ifdef CONFIG_LOCKDEP
+	/**
+	 * @lock_dep_map: Annotates drm_gpusvm_range_find_or_insert and
+	 * drm_gpusvm_range_remove with a driver provided lock.
+	 */
+	struct lockdep_map *lock_dep_map;
+#endif
+};
+
+/**
+ * struct drm_gpusvm_ctx - DRM GPU SVM context
+ *
+ * @check_pages_threshold: Check CPU pages for present if chunk is less than or
+ *                         equal to threshold. If not present, reduce chunk
+ *                         size.
+ * @in_notifier: entering from a MMU notifier
+ * @read_only: operating on read-only memory
+ * @devmem_possible: possible to use device memory
+ *
+ * Context that is DRM GPUSVM is operating in (i.e. user arguments).
+ */
+struct drm_gpusvm_ctx {
+	unsigned long check_pages_threshold;
+	unsigned int in_notifier :1;
+	unsigned int read_only :1;
+	unsigned int devmem_possible :1;
+};
+
+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);
+
+void drm_gpusvm_fini(struct drm_gpusvm *gpusvm);
+
+void drm_gpusvm_free(struct drm_gpusvm *gpusvm);
+
+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);
+
+void drm_gpusvm_range_remove(struct drm_gpusvm *gpusvm,
+			     struct drm_gpusvm_range *range);
+
+int drm_gpusvm_range_evict(struct drm_gpusvm *gpusvm,
+			   struct drm_gpusvm_range *range);
+
+struct drm_gpusvm_range *
+drm_gpusvm_range_get(struct drm_gpusvm_range *range);
+
+void drm_gpusvm_range_put(struct drm_gpusvm_range *range);
+
+bool drm_gpusvm_range_pages_valid(struct drm_gpusvm *gpusvm,
+				  struct drm_gpusvm_range *range);
+
+int drm_gpusvm_range_get_pages(struct drm_gpusvm *gpusvm,
+			       struct drm_gpusvm_range *range,
+			       const struct drm_gpusvm_ctx *ctx);
+
+void drm_gpusvm_range_unmap_pages(struct drm_gpusvm *gpusvm,
+				  struct drm_gpusvm_range *range,
+				  const struct drm_gpusvm_ctx *ctx);
+
+int drm_gpusvm_migrate_to_devmem(struct drm_gpusvm *gpusvm,
+				 struct drm_gpusvm_range *range,
+				 struct drm_gpusvm_devmem *devmem_allocation,
+				 const struct drm_gpusvm_ctx *ctx);
+
+int drm_gpusvm_evict_to_ram(struct drm_gpusvm_devmem *devmem_allocation);
+
+const struct dev_pagemap_ops *drm_gpusvm_pagemap_ops_get(void);
+
+bool drm_gpusvm_has_mapping(struct drm_gpusvm *gpusvm, unsigned long start,
+			    unsigned long end);
+
+struct drm_gpusvm_range *
+drm_gpusvm_range_find(struct drm_gpusvm_notifier *notifier, unsigned long start,
+		      unsigned long end);
+
+void drm_gpusvm_range_set_unmapped(struct drm_gpusvm_range *range,
+				   const struct mmu_notifier_range *mmu_range);
+
+void drm_gpusvm_devmem_init(struct drm_gpusvm_devmem *devmem_allocation,
+			    struct device *dev, struct mm_struct *mm,
+			    const struct drm_gpusvm_devmem_ops *ops,
+			    struct drm_pagemap *dpagemap, size_t size);
+
+#ifdef CONFIG_LOCKDEP
+/**
+ * drm_gpusvm_driver_set_lock() - Set the lock protecting accesses to GPU SVM
+ * @gpusvm: Pointer to the GPU SVM structure.
+ * @lock: the lock used to protect the gpuva list. The locking primitive
+ * must contain a dep_map field.
+ *
+ * Call this to annotate drm_gpusvm_range_find_or_insert and
+ * drm_gpusvm_range_remove.
+ */
+#define drm_gpusvm_driver_set_lock(gpusvm, lock) \
+	do { \
+		if (!WARN((gpusvm)->lock_dep_map, \
+			  "GPUSVM range lock should be set only once."))\
+			(gpusvm)->lock_dep_map = &(lock)->dep_map;	\
+	} while (0)
+#else
+#define drm_gpusvm_driver_set_lock(gpusvm, lock) do {} while (0)
+#endif
+
+/**
+ * drm_gpusvm_notifier_lock() - Lock GPU SVM notifier
+ * @gpusvm__: Pointer to the GPU SVM structure.
+ *
+ * Abstract client usage GPU SVM notifier lock, take lock
+ */
+#define drm_gpusvm_notifier_lock(gpusvm__)	\
+	down_read(&(gpusvm__)->notifier_lock)
+
+/**
+ * drm_gpusvm_notifier_unlock() - Unlock GPU SVM notifier
+ * @gpusvm__: Pointer to the GPU SVM structure.
+ *
+ * Abstract client usage GPU SVM notifier lock, drop lock
+ */
+#define drm_gpusvm_notifier_unlock(gpusvm__)	\
+	up_read(&(gpusvm__)->notifier_lock)
+
+/**
+ * drm_gpusvm_range_start() - GPU SVM range start address
+ * @range: Pointer to the GPU SVM range
+ *
+ * Return: GPU SVM range start address
+ */
+static inline unsigned long
+drm_gpusvm_range_start(struct drm_gpusvm_range *range)
+{
+	return range->itree.start;
+}
+
+/**
+ * drm_gpusvm_range_end() - GPU SVM range end address
+ * @range: Pointer to the GPU SVM range
+ *
+ * Return: GPU SVM range end address
+ */
+static inline unsigned long
+drm_gpusvm_range_end(struct drm_gpusvm_range *range)
+{
+	return range->itree.last + 1;
+}
+
+/**
+ * drm_gpusvm_range_size() - GPU SVM range size
+ * @range: Pointer to the GPU SVM range
+ *
+ * Return: GPU SVM range size
+ */
+static inline unsigned long
+drm_gpusvm_range_size(struct drm_gpusvm_range *range)
+{
+	return drm_gpusvm_range_end(range) - drm_gpusvm_range_start(range);
+}
+
+/**
+ * drm_gpusvm_notifier_start() - GPU SVM notifier start address
+ * @notifier: Pointer to the GPU SVM notifier
+ *
+ * Return: GPU SVM notifier start address
+ */
+static inline unsigned long
+drm_gpusvm_notifier_start(struct drm_gpusvm_notifier *notifier)
+{
+	return notifier->itree.start;
+}
+
+/**
+ * drm_gpusvm_notifier_end() - GPU SVM notifier end address
+ * @notifier: Pointer to the GPU SVM notifier
+ *
+ * Return: GPU SVM notifier end address
+ */
+static inline unsigned long
+drm_gpusvm_notifier_end(struct drm_gpusvm_notifier *notifier)
+{
+	return notifier->itree.last + 1;
+}
+
+/**
+ * drm_gpusvm_notifier_size() - GPU SVM notifier size
+ * @notifier: Pointer to the GPU SVM notifier
+ *
+ * Return: GPU SVM notifier size
+ */
+static inline unsigned long
+drm_gpusvm_notifier_size(struct drm_gpusvm_notifier *notifier)
+{
+	return drm_gpusvm_notifier_end(notifier) -
+		drm_gpusvm_notifier_start(notifier);
+}
+
+/**
+ * __drm_gpusvm_range_next() - Get the next GPU SVM range in the list
+ * @range: a pointer to the current GPU SVM range
+ *
+ * Return: A pointer to the next drm_gpusvm_range if available, or NULL if the
+ *         current range is the last one or if the input range is NULL.
+ */
+static inline struct drm_gpusvm_range *
+__drm_gpusvm_range_next(struct drm_gpusvm_range *range)
+{
+	if (range && !list_is_last(&range->entry,
+				   &range->notifier->range_list))
+		return list_next_entry(range, entry);
+
+	return NULL;
+}
+
+/**
+ * drm_gpusvm_for_each_range() - Iterate over GPU SVM ranges in a notifier
+ * @range__: Iterator variable for the ranges. If set, it indicates the start of
+ *	     the iterator. If NULL, call drm_gpusvm_range_find() to get the range.
+ * @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. It is safe
+ * to use while holding the driver SVM lock or the notifier lock.
+ */
+#define drm_gpusvm_for_each_range(range__, notifier__, start__, end__)	\
+	for ((range__) = (range__) ?:					\
+	     drm_gpusvm_range_find((notifier__), (start__), (end__));	\
+	     (range__) && (drm_gpusvm_range_start(range__) < (end__));	\
+	     (range__) = __drm_gpusvm_range_next(range__))
+
+#endif /* __DRM_GPUSVM_H__ */