drm/gpuvm: rename struct drm_gpuva_manager to struct drm_gpuvm

Rename struct drm_gpuva_manager to struct drm_gpuvm including
corresponding functions. This way the GPUVA manager's structures align
very well with the documentation of VM_BIND [1] and VM_BIND locking [2].

It also provides a better foundation for the naming of data structures
and functions introduced for implementing a common dma-resv per GPU-VM
including tracking of external and evicted objects in subsequent
patches.

[1] Documentation/gpu/drm-vm-bind-async.rst
[2] Documentation/gpu/drm-vm-bind-locking.rst

Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Cc: Matthew Brost <matthew.brost@intel.com>
Acked-by: Dave Airlie <airlied@redhat.com>
Acked-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Danilo Krummrich <dakr@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230920144343.64830-2-dakr@redhat.com

1 files changed, 1725 insertions, 0 deletions

diff --git a/drivers/gpu/drm/drm_gpuvm.c b/drivers/gpu/drm/drm_gpuvm.c
new file mode 100644
index 000000000000..d55267db76ae
--- /dev/null
+++ b/drivers/gpu/drm/drm_gpuvm.c
@@ -0,0 +1,1725 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2022 Red Hat.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
+ * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
+ * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+ * OTHER DEALINGS IN THE SOFTWARE.
+ *
+ * Authors:
+ *     Danilo Krummrich <dakr@redhat.com>
+ *
+ */
+
+#include <drm/drm_gpuvm.h>
+
+#include <linux/interval_tree_generic.h>
+#include <linux/mm.h>
+
+/**
+ * DOC: Overview
+ *
+ * The DRM GPU VA Manager, represented by struct drm_gpuvm keeps track of a
+ * GPU's virtual address (VA) space and manages the corresponding virtual
+ * mappings represented by &drm_gpuva objects. It also keeps track of the
+ * mapping's backing &drm_gem_object buffers.
+ *
+ * &drm_gem_object buffers maintain a list of &drm_gpuva objects representing
+ * all existent GPU VA mappings using this &drm_gem_object as backing buffer.
+ *
+ * GPU VAs can be flagged as sparse, such that drivers may use GPU VAs to also
+ * keep track of sparse PTEs in order to support Vulkan 'Sparse Resources'.
+ *
+ * The GPU VA manager internally uses a rb-tree to manage the
+ * &drm_gpuva mappings within a GPU's virtual address space.
+ *
+ * The &drm_gpuvm structure contains a special &drm_gpuva representing the
+ * portion of VA space reserved by the kernel. This node is initialized together
+ * with the GPU VA manager instance and removed when the GPU VA manager is
+ * destroyed.
+ *
+ * In a typical application drivers would embed struct drm_gpuvm and
+ * struct drm_gpuva within their own driver specific structures, there won't be
+ * any memory allocations of its own nor memory allocations of &drm_gpuva
+ * entries.
+ *
+ * The data structures needed to store &drm_gpuvas within the &drm_gpuvm are
+ * contained within struct drm_gpuva already. Hence, for inserting &drm_gpuva
+ * entries from within dma-fence signalling critical sections it is enough to
+ * pre-allocate the &drm_gpuva structures.
+ */
+
+/**
+ * DOC: Split and Merge
+ *
+ * Besides its capability to manage and represent a GPU VA space, the
+ * GPU VA manager also provides functions to let the &drm_gpuvm calculate a
+ * sequence of operations to satisfy a given map or unmap request.
+ *
+ * Therefore the DRM GPU VA manager provides an algorithm implementing splitting
+ * and merging of existent GPU VA mappings with the ones that are requested to
+ * be mapped or unmapped. This feature is required by the Vulkan API to
+ * implement Vulkan 'Sparse Memory Bindings' - drivers UAPIs often refer to this
+ * as VM BIND.
+ *
+ * Drivers can call drm_gpuvm_sm_map() to receive a sequence of callbacks
+ * containing map, unmap and remap operations for a given newly requested
+ * mapping. The sequence of callbacks represents the set of operations to
+ * execute in order to integrate the new mapping cleanly into the current state
+ * of the GPU VA space.
+ *
+ * Depending on how the new GPU VA mapping intersects with the existent mappings
+ * of the GPU VA space the &drm_gpuvm_ops callbacks contain an arbitrary amount
+ * of unmap operations, a maximum of two remap operations and a single map
+ * operation. The caller might receive no callback at all if no operation is
+ * required, e.g. if the requested mapping already exists in the exact same way.
+ *
+ * The single map operation represents the original map operation requested by
+ * the caller.
+ *
+ * &drm_gpuva_op_unmap contains a 'keep' field, which indicates whether the
+ * &drm_gpuva to unmap is physically contiguous with the original mapping
+ * request. Optionally, if 'keep' is set, drivers may keep the actual page table
+ * entries for this &drm_gpuva, adding the missing page table entries only and
+ * update the &drm_gpuvm's view of things accordingly.
+ *
+ * Drivers may do the same optimization, namely delta page table updates, also
+ * for remap operations. This is possible since &drm_gpuva_op_remap consists of
+ * one unmap operation and one or two map operations, such that drivers can
+ * derive the page table update delta accordingly.
+ *
+ * Note that there can't be more than two existent mappings to split up, one at
+ * the beginning and one at the end of the new mapping, hence there is a
+ * maximum of two remap operations.
+ *
+ * Analogous to drm_gpuvm_sm_map() drm_gpuvm_sm_unmap() uses &drm_gpuvm_ops to
+ * call back into the driver in order to unmap a range of GPU VA space. The
+ * logic behind this function is way simpler though: For all existent mappings
+ * enclosed by the given range unmap operations are created. For mappings which
+ * are only partically located within the given range, remap operations are
+ * created such that those mappings are split up and re-mapped partically.
+ *
+ * As an alternative to drm_gpuvm_sm_map() and drm_gpuvm_sm_unmap(),
+ * drm_gpuvm_sm_map_ops_create() and drm_gpuvm_sm_unmap_ops_create() can be used
+ * to directly obtain an instance of struct drm_gpuva_ops containing a list of
+ * &drm_gpuva_op, which can be iterated with drm_gpuva_for_each_op(). This list
+ * contains the &drm_gpuva_ops analogous to the callbacks one would receive when
+ * calling drm_gpuvm_sm_map() or drm_gpuvm_sm_unmap(). While this way requires
+ * more memory (to allocate the &drm_gpuva_ops), it provides drivers a way to
+ * iterate the &drm_gpuva_op multiple times, e.g. once in a context where memory
+ * allocations are possible (e.g. to allocate GPU page tables) and once in the
+ * dma-fence signalling critical path.
+ *
+ * To update the &drm_gpuvm's view of the GPU VA space drm_gpuva_insert() and
+ * drm_gpuva_remove() may be used. These functions can safely be used from
+ * &drm_gpuvm_ops callbacks originating from drm_gpuvm_sm_map() or
+ * drm_gpuvm_sm_unmap(). However, it might be more convenient to use the
+ * provided helper functions drm_gpuva_map(), drm_gpuva_remap() and
+ * drm_gpuva_unmap() instead.
+ *
+ * The following diagram depicts the basic relationships of existent GPU VA
+ * mappings, a newly requested mapping and the resulting mappings as implemented
+ * by drm_gpuvm_sm_map() - it doesn't cover any arbitrary combinations of these.
+ *
+ * 1) Requested mapping is identical. Replace it, but indicate the backing PTEs
+ *    could be kept.
+ *
+ *    ::
+ *
+ *	     0     a     1
+ *	old: |-----------| (bo_offset=n)
+ *
+ *	     0     a     1
+ *	req: |-----------| (bo_offset=n)
+ *
+ *	     0     a     1
+ *	new: |-----------| (bo_offset=n)
+ *
+ *
+ * 2) Requested mapping is identical, except for the BO offset, hence replace
+ *    the mapping.
+ *
+ *    ::
+ *
+ *	     0     a     1
+ *	old: |-----------| (bo_offset=n)
+ *
+ *	     0     a     1
+ *	req: |-----------| (bo_offset=m)
+ *
+ *	     0     a     1
+ *	new: |-----------| (bo_offset=m)
+ *
+ *
+ * 3) Requested mapping is identical, except for the backing BO, hence replace
+ *    the mapping.
+ *
+ *    ::
+ *
+ *	     0     a     1
+ *	old: |-----------| (bo_offset=n)
+ *
+ *	     0     b     1
+ *	req: |-----------| (bo_offset=n)
+ *
+ *	     0     b     1
+ *	new: |-----------| (bo_offset=n)
+ *
+ *
+ * 4) Existent mapping is a left aligned subset of the requested one, hence
+ *    replace the existent one.
+ *
+ *    ::
+ *
+ *	     0  a  1
+ *	old: |-----|       (bo_offset=n)
+ *
+ *	     0     a     2
+ *	req: |-----------| (bo_offset=n)
+ *
+ *	     0     a     2
+ *	new: |-----------| (bo_offset=n)
+ *
+ *    .. note::
+ *       We expect to see the same result for a request with a different BO
+ *       and/or non-contiguous BO offset.
+ *
+ *
+ * 5) Requested mapping's range is a left aligned subset of the existent one,
+ *    but backed by a different BO. Hence, map the requested mapping and split
+ *    the existent one adjusting its BO offset.
+ *
+ *    ::
+ *
+ *	     0     a     2
+ *	old: |-----------| (bo_offset=n)
+ *
+ *	     0  b  1
+ *	req: |-----|       (bo_offset=n)
+ *
+ *	     0  b  1  a' 2
+ *	new: |-----|-----| (b.bo_offset=n, a.bo_offset=n+1)
+ *
+ *    .. note::
+ *       We expect to see the same result for a request with a different BO
+ *       and/or non-contiguous BO offset.
+ *
+ *
+ * 6) Existent mapping is a superset of the requested mapping. Split it up, but
+ *    indicate that the backing PTEs could be kept.
+ *
+ *    ::
+ *
+ *	     0     a     2
+ *	old: |-----------| (bo_offset=n)
+ *
+ *	     0  a  1
+ *	req: |-----|       (bo_offset=n)
+ *
+ *	     0  a  1  a' 2
+ *	new: |-----|-----| (a.bo_offset=n, a'.bo_offset=n+1)
+ *
+ *
+ * 7) Requested mapping's range is a right aligned subset of the existent one,
+ *    but backed by a different BO. Hence, map the requested mapping and split
+ *    the existent one, without adjusting the BO offset.
+ *
+ *    ::
+ *
+ *	     0     a     2
+ *	old: |-----------| (bo_offset=n)
+ *
+ *	           1  b  2
+ *	req:       |-----| (bo_offset=m)
+ *
+ *	     0  a  1  b  2
+ *	new: |-----|-----| (a.bo_offset=n,b.bo_offset=m)
+ *
+ *
+ * 8) Existent mapping is a superset of the requested mapping. Split it up, but
+ *    indicate that the backing PTEs could be kept.
+ *
+ *    ::
+ *
+ *	      0     a     2
+ *	old: |-----------| (bo_offset=n)
+ *
+ *	           1  a  2
+ *	req:       |-----| (bo_offset=n+1)
+ *
+ *	     0  a' 1  a  2
+ *	new: |-----|-----| (a'.bo_offset=n, a.bo_offset=n+1)
+ *
+ *
+ * 9) Existent mapping is overlapped at the end by the requested mapping backed
+ *    by a different BO. Hence, map the requested mapping and split up the
+ *    existent one, without adjusting the BO offset.
+ *
+ *    ::
+ *
+ *	     0     a     2
+ *	old: |-----------|       (bo_offset=n)
+ *
+ *	           1     b     3
+ *	req:       |-----------| (bo_offset=m)
+ *
+ *	     0  a  1     b     3
+ *	new: |-----|-----------| (a.bo_offset=n,b.bo_offset=m)
+ *
+ *
+ * 10) Existent mapping is overlapped by the requested mapping, both having the
+ *     same backing BO with a contiguous offset. Indicate the backing PTEs of
+ *     the old mapping could be kept.
+ *
+ *     ::
+ *
+ *	      0     a     2
+ *	 old: |-----------|       (bo_offset=n)
+ *
+ *	            1     a     3
+ *	 req:       |-----------| (bo_offset=n+1)
+ *
+ *	      0  a' 1     a     3
+ *	 new: |-----|-----------| (a'.bo_offset=n, a.bo_offset=n+1)
+ *
+ *
+ * 11) Requested mapping's range is a centered subset of the existent one
+ *     having a different backing BO. Hence, map the requested mapping and split
+ *     up the existent one in two mappings, adjusting the BO offset of the right
+ *     one accordingly.
+ *
+ *     ::
+ *
+ *	      0        a        3
+ *	 old: |-----------------| (bo_offset=n)
+ *
+ *	            1  b  2
+ *	 req:       |-----|       (bo_offset=m)
+ *
+ *	      0  a  1  b  2  a' 3
+ *	 new: |-----|-----|-----| (a.bo_offset=n,b.bo_offset=m,a'.bo_offset=n+2)
+ *
+ *
+ * 12) Requested mapping is a contiguous subset of the existent one. Split it
+ *     up, but indicate that the backing PTEs could be kept.
+ *
+ *     ::
+ *
+ *	      0        a        3
+ *	 old: |-----------------| (bo_offset=n)
+ *
+ *	            1  a  2
+ *	 req:       |-----|       (bo_offset=n+1)
+ *
+ *	      0  a' 1  a  2 a'' 3
+ *	 old: |-----|-----|-----| (a'.bo_offset=n, a.bo_offset=n+1, a''.bo_offset=n+2)
+ *
+ *
+ * 13) Existent mapping is a right aligned subset of the requested one, hence
+ *     replace the existent one.
+ *
+ *     ::
+ *
+ *	            1  a  2
+ *	 old:       |-----| (bo_offset=n+1)
+ *
+ *	      0     a     2
+ *	 req: |-----------| (bo_offset=n)
+ *
+ *	      0     a     2
+ *	 new: |-----------| (bo_offset=n)
+ *
+ *     .. note::
+ *        We expect to see the same result for a request with a different bo
+ *        and/or non-contiguous bo_offset.
+ *
+ *
+ * 14) Existent mapping is a centered subset of the requested one, hence
+ *     replace the existent one.
+ *
+ *     ::
+ *
+ *	            1  a  2
+ *	 old:       |-----| (bo_offset=n+1)
+ *
+ *	      0        a       3
+ *	 req: |----------------| (bo_offset=n)
+ *
+ *	      0        a       3
+ *	 new: |----------------| (bo_offset=n)
+ *
+ *     .. note::
+ *        We expect to see the same result for a request with a different bo
+ *        and/or non-contiguous bo_offset.
+ *
+ *
+ * 15) Existent mappings is overlapped at the beginning by the requested mapping
+ *     backed by a different BO. Hence, map the requested mapping and split up
+ *     the existent one, adjusting its BO offset accordingly.
+ *
+ *     ::
+ *
+ *	            1     a     3
+ *	 old:       |-----------| (bo_offset=n)
+ *
+ *	      0     b     2
+ *	 req: |-----------|       (bo_offset=m)
+ *
+ *	      0     b     2  a' 3
+ *	 new: |-----------|-----| (b.bo_offset=m,a.bo_offset=n+2)
+ */
+
+/**
+ * DOC: Locking
+ *
+ * Generally, the GPU VA manager does not take care of locking itself, it is
+ * the drivers responsibility to take care about locking. Drivers might want to
+ * protect the following operations: inserting, removing and iterating
+ * &drm_gpuva objects as well as generating all kinds of operations, such as
+ * split / merge or prefetch.
+ *
+ * The GPU VA manager also does not take care of the locking of the backing
+ * &drm_gem_object buffers GPU VA lists by itself; drivers are responsible to
+ * enforce mutual exclusion using either the GEMs dma_resv lock or alternatively
+ * a driver specific external lock. For the latter see also
+ * drm_gem_gpuva_set_lock().
+ *
+ * However, the GPU VA manager contains lockdep checks to ensure callers of its
+ * API hold the corresponding lock whenever the &drm_gem_objects GPU VA list is
+ * accessed by functions such as drm_gpuva_link() or drm_gpuva_unlink().
+ */
+
+/**
+ * DOC: Examples
+ *
+ * This section gives two examples on how to let the DRM GPUVA Manager generate
+ * &drm_gpuva_op in order to satisfy a given map or unmap request and how to
+ * make use of them.
+ *
+ * The below code is strictly limited to illustrate the generic usage pattern.
+ * To maintain simplicitly, it doesn't make use of any abstractions for common
+ * code, different (asyncronous) stages with fence signalling critical paths,
+ * any other helpers or error handling in terms of freeing memory and dropping
+ * previously taken locks.
+ *
+ * 1) Obtain a list of &drm_gpuva_op to create a new mapping::
+ *
+ *	// Allocates a new &drm_gpuva.
+ *	struct drm_gpuva * driver_gpuva_alloc(void);
+ *
+ *	// Typically drivers would embedd the &drm_gpuvm and &drm_gpuva
+ *	// structure in individual driver structures and lock the dma-resv with
+ *	// drm_exec or similar helpers.
+ *	int driver_mapping_create(struct drm_gpuvm *gpuvm,
+ *				  u64 addr, u64 range,
+ *				  struct drm_gem_object *obj, u64 offset)
+ *	{
+ *		struct drm_gpuva_ops *ops;
+ *		struct drm_gpuva_op *op
+ *
+ *		driver_lock_va_space();
+ *		ops = drm_gpuvm_sm_map_ops_create(gpuvm, addr, range,
+ *						  obj, offset);
+ *		if (IS_ERR(ops))
+ *			return PTR_ERR(ops);
+ *
+ *		drm_gpuva_for_each_op(op, ops) {
+ *			struct drm_gpuva *va;
+ *
+ *			switch (op->op) {
+ *			case DRM_GPUVA_OP_MAP:
+ *				va = driver_gpuva_alloc();
+ *				if (!va)
+ *					; // unwind previous VA space updates,
+ *					  // free memory and unlock
+ *
+ *				driver_vm_map();
+ *				drm_gpuva_map(gpuvm, va, &op->map);
+ *				drm_gpuva_link(va);
+ *
+ *				break;
+ *			case DRM_GPUVA_OP_REMAP: {
+ *				struct drm_gpuva *prev = NULL, *next = NULL;
+ *
+ *				va = op->remap.unmap->va;
+ *
+ *				if (op->remap.prev) {
+ *					prev = driver_gpuva_alloc();
+ *					if (!prev)
+ *						; // unwind previous VA space
+ *						  // updates, free memory and
+ *						  // unlock
+ *				}
+ *
+ *				if (op->remap.next) {
+ *					next = driver_gpuva_alloc();
+ *					if (!next)
+ *						; // unwind previous VA space
+ *						  // updates, free memory and
+ *						  // unlock
+ *				}
+ *
+ *				driver_vm_remap();
+ *				drm_gpuva_remap(prev, next, &op->remap);
+ *
+ *				drm_gpuva_unlink(va);
+ *				if (prev)
+ *					drm_gpuva_link(prev);
+ *				if (next)
+ *					drm_gpuva_link(next);
+ *
+ *				break;
+ *			}
+ *			case DRM_GPUVA_OP_UNMAP:
+ *				va = op->unmap->va;
+ *
+ *				driver_vm_unmap();
+ *				drm_gpuva_unlink(va);
+ *				drm_gpuva_unmap(&op->unmap);
+ *
+ *				break;
+ *			default:
+ *				break;
+ *			}
+ *		}
+ *		driver_unlock_va_space();
+ *
+ *		return 0;
+ *	}
+ *
+ * 2) Receive a callback for each &drm_gpuva_op to create a new mapping::
+ *
+ *	struct driver_context {
+ *		struct drm_gpuvm *gpuvm;
+ *		struct drm_gpuva *new_va;
+ *		struct drm_gpuva *prev_va;
+ *		struct drm_gpuva *next_va;
+ *	};
+ *
+ *	// ops to pass to drm_gpuvm_init()
+ *	static const struct drm_gpuvm_ops driver_gpuvm_ops = {
+ *		.sm_step_map = driver_gpuva_map,
+ *		.sm_step_remap = driver_gpuva_remap,
+ *		.sm_step_unmap = driver_gpuva_unmap,
+ *	};
+ *
+ *	// Typically drivers would embedd the &drm_gpuvm and &drm_gpuva
+ *	// structure in individual driver structures and lock the dma-resv with
+ *	// drm_exec or similar helpers.
+ *	int driver_mapping_create(struct drm_gpuvm *gpuvm,
+ *				  u64 addr, u64 range,
+ *				  struct drm_gem_object *obj, u64 offset)
+ *	{
+ *		struct driver_context ctx;
+ *		struct drm_gpuva_ops *ops;
+ *		struct drm_gpuva_op *op;
+ *		int ret = 0;
+ *
+ *		ctx.gpuvm = gpuvm;
+ *
+ *		ctx.new_va = kzalloc(sizeof(*ctx.new_va), GFP_KERNEL);
+ *		ctx.prev_va = kzalloc(sizeof(*ctx.prev_va), GFP_KERNEL);
+ *		ctx.next_va = kzalloc(sizeof(*ctx.next_va), GFP_KERNEL);
+ *		if (!ctx.new_va || !ctx.prev_va || !ctx.next_va) {
+ *			ret = -ENOMEM;
+ *			goto out;
+ *		}
+ *
+ *		driver_lock_va_space();
+ *		ret = drm_gpuvm_sm_map(gpuvm, &ctx, addr, range, obj, offset);
+ *		driver_unlock_va_space();
+ *
+ *	out:
+ *		kfree(ctx.new_va);
+ *		kfree(ctx.prev_va);
+ *		kfree(ctx.next_va);
+ *		return ret;
+ *	}
+ *
+ *	int driver_gpuva_map(struct drm_gpuva_op *op, void *__ctx)
+ *	{
+ *		struct driver_context *ctx = __ctx;
+ *
+ *		drm_gpuva_map(ctx->vm, ctx->new_va, &op->map);
+ *
+ *		drm_gpuva_link(ctx->new_va);
+ *
+ *		// prevent the new GPUVA from being freed in
+ *		// driver_mapping_create()
+ *		ctx->new_va = NULL;
+ *
+ *		return 0;
+ *	}
+ *
+ *	int driver_gpuva_remap(struct drm_gpuva_op *op, void *__ctx)
+ *	{
+ *		struct driver_context *ctx = __ctx;
+ *
+ *		drm_gpuva_remap(ctx->prev_va, ctx->next_va, &op->remap);
+ *
+ *		drm_gpuva_unlink(op->remap.unmap->va);
+ *		kfree(op->remap.unmap->va);
+ *
+ *		if (op->remap.prev) {
+ *			drm_gpuva_link(ctx->prev_va);
+ *			ctx->prev_va = NULL;
+ *		}
+ *
+ *		if (op->remap.next) {
+ *			drm_gpuva_link(ctx->next_va);
+ *			ctx->next_va = NULL;
+ *		}
+ *
+ *		return 0;
+ *	}
+ *
+ *	int driver_gpuva_unmap(struct drm_gpuva_op *op, void *__ctx)
+ *	{
+ *		drm_gpuva_unlink(op->unmap.va);
+ *		drm_gpuva_unmap(&op->unmap);
+ *		kfree(op->unmap.va);
+ *
+ *		return 0;
+ *	}
+ */
+
+#define to_drm_gpuva(__node)	container_of((__node), struct drm_gpuva, rb.node)
+
+#define GPUVA_START(node) ((node)->va.addr)
+#define GPUVA_LAST(node) ((node)->va.addr + (node)->va.range - 1)
+
+/* We do not actually use drm_gpuva_it_next(), tell the compiler to not complain
+ * about this.
+ */
+INTERVAL_TREE_DEFINE(struct drm_gpuva, rb.node, u64, rb.__subtree_last,
+		     GPUVA_START, GPUVA_LAST, static __maybe_unused,
+		     drm_gpuva_it)
+
+static int __drm_gpuva_insert(struct drm_gpuvm *gpuvm,
+			      struct drm_gpuva *va);
+static void __drm_gpuva_remove(struct drm_gpuva *va);
+
+static bool
+drm_gpuvm_check_overflow(u64 addr, u64 range)
+{
+	u64 end;
+
+	return WARN(check_add_overflow(addr, range, &end),
+		    "GPUVA address limited to %zu bytes.\n", sizeof(end));
+}
+
+static bool
+drm_gpuvm_in_mm_range(struct drm_gpuvm *gpuvm, u64 addr, u64 range)
+{
+	u64 end = addr + range;
+	u64 mm_start = gpuvm->mm_start;
+	u64 mm_end = mm_start + gpuvm->mm_range;
+
+	return addr >= mm_start && end <= mm_end;
+}
+
+static bool
+drm_gpuvm_in_kernel_node(struct drm_gpuvm *gpuvm, u64 addr, u64 range)
+{
+	u64 end = addr + range;
+	u64 kstart = gpuvm->kernel_alloc_node.va.addr;
+	u64 krange = gpuvm->kernel_alloc_node.va.range;
+	u64 kend = kstart + krange;
+
+	return krange && addr < kend && kstart < end;
+}
+
+static bool
+drm_gpuvm_range_valid(struct drm_gpuvm *gpuvm,
+		      u64 addr, u64 range)
+{
+	return !drm_gpuvm_check_overflow(addr, range) &&
+	       drm_gpuvm_in_mm_range(gpuvm, addr, range) &&
+	       !drm_gpuvm_in_kernel_node(gpuvm, addr, range);
+}
+
+/**
+ * drm_gpuvm_init() - initialize a &drm_gpuvm
+ * @gpuvm: pointer to the &drm_gpuvm to initialize
+ * @name: the name of the GPU VA space
+ * @start_offset: the start offset of the GPU VA space
+ * @range: the size of the GPU VA space
+ * @reserve_offset: the start of the kernel reserved GPU VA area
+ * @reserve_range: the size of the kernel reserved GPU VA area
+ * @ops: &drm_gpuvm_ops called on &drm_gpuvm_sm_map / &drm_gpuvm_sm_unmap
+ *
+ * The &drm_gpuvm must be initialized with this function before use.
+ *
+ * Note that @gpuvm must be cleared to 0 before calling this function. The given
+ * &name is expected to be managed by the surrounding driver structures.
+ */
+void
+drm_gpuvm_init(struct drm_gpuvm *gpuvm,
+	       const char *name,
+	       u64 start_offset, u64 range,
+	       u64 reserve_offset, u64 reserve_range,
+	       const struct drm_gpuvm_ops *ops)
+{
+	gpuvm->rb.tree = RB_ROOT_CACHED;
+	INIT_LIST_HEAD(&gpuvm->rb.list);
+
+	drm_gpuvm_check_overflow(start_offset, range);
+	gpuvm->mm_start = start_offset;
+	gpuvm->mm_range = range;
+
+	gpuvm->name = name ? name : "unknown";
+	gpuvm->ops = ops;
+
+	memset(&gpuvm->kernel_alloc_node, 0, sizeof(struct drm_gpuva));
+
+	if (reserve_range) {
+		gpuvm->kernel_alloc_node.va.addr = reserve_offset;
+		gpuvm->kernel_alloc_node.va.range = reserve_range;
+
+		if (likely(!drm_gpuvm_check_overflow(reserve_offset,
+						     reserve_range)))
+			__drm_gpuva_insert(gpuvm, &gpuvm->kernel_alloc_node);
+	}
+}
+EXPORT_SYMBOL_GPL(drm_gpuvm_init);
+
+/**
+ * drm_gpuvm_destroy() - cleanup a &drm_gpuvm
+ * @gpuvm: pointer to the &drm_gpuvm to clean up
+ *
+ * Note that it is a bug to call this function on a manager that still
+ * holds GPU VA mappings.
+ */
+void
+drm_gpuvm_destroy(struct drm_gpuvm *gpuvm)
+{
+	gpuvm->name = NULL;
+
+	if (gpuvm->kernel_alloc_node.va.range)
+		__drm_gpuva_remove(&gpuvm->kernel_alloc_node);
+
+	WARN(!RB_EMPTY_ROOT(&gpuvm->rb.tree.rb_root),
+	     "GPUVA tree is not empty, potentially leaking memory.");
+}
+EXPORT_SYMBOL_GPL(drm_gpuvm_destroy);
+
+static int
+__drm_gpuva_insert(struct drm_gpuvm *gpuvm,
+		   struct drm_gpuva *va)
+{
+	struct rb_node *node;
+	struct list_head *head;
+
+	if (drm_gpuva_it_iter_first(&gpuvm->rb.tree,
+				    GPUVA_START(va),
+				    GPUVA_LAST(va)))
+		return -EEXIST;
+
+	va->vm = gpuvm;
+
+	drm_gpuva_it_insert(va, &gpuvm->rb.tree);
+
+	node = rb_prev(&va->rb.node);
+	if (node)
+		head = &(to_drm_gpuva(node))->rb.entry;
+	else
+		head = &gpuvm->rb.list;
+
+	list_add(&va->rb.entry, head);
+
+	return 0;
+}
+
+/**
+ * drm_gpuva_insert() - insert a &drm_gpuva
+ * @gpuvm: the &drm_gpuvm to insert the &drm_gpuva in
+ * @va: the &drm_gpuva to insert
+ *
+ * Insert a &drm_gpuva with a given address and range into a
+ * &drm_gpuvm.
+ *
+ * It is safe to use this function using the safe versions of iterating the GPU
+ * VA space, such as drm_gpuvm_for_each_va_safe() and
+ * drm_gpuvm_for_each_va_range_safe().
+ *
+ * Returns: 0 on success, negative error code on failure.
+ */
+int
+drm_gpuva_insert(struct drm_gpuvm *gpuvm,
+		 struct drm_gpuva *va)
+{
+	u64 addr = va->va.addr;
+	u64 range = va->va.range;
+
+	if (unlikely(!drm_gpuvm_range_valid(gpuvm, addr, range)))
+		return -EINVAL;
+
+	return __drm_gpuva_insert(gpuvm, va);
+}
+EXPORT_SYMBOL_GPL(drm_gpuva_insert);
+
+static void
+__drm_gpuva_remove(struct drm_gpuva *va)
+{
+	drm_gpuva_it_remove(va, &va->vm->rb.tree);
+	list_del_init(&va->rb.entry);
+}
+
+/**
+ * drm_gpuva_remove() - remove a &drm_gpuva
+ * @va: the &drm_gpuva to remove
+ *
+ * This removes the given &va from the underlaying tree.
+ *
+ * It is safe to use this function using the safe versions of iterating the GPU
+ * VA space, such as drm_gpuvm_for_each_va_safe() and
+ * drm_gpuvm_for_each_va_range_safe().
+ */
+void
+drm_gpuva_remove(struct drm_gpuva *va)
+{
+	struct drm_gpuvm *gpuvm = va->vm;
+
+	if (unlikely(va == &gpuvm->kernel_alloc_node)) {
+		WARN(1, "Can't destroy kernel reserved node.\n");
+		return;
+	}
+
+	__drm_gpuva_remove(va);
+}
+EXPORT_SYMBOL_GPL(drm_gpuva_remove);
+
+/**
+ * drm_gpuva_link() - link a &drm_gpuva
+ * @va: the &drm_gpuva to link
+ *
+ * This adds the given &va to the GPU VA list of the &drm_gem_object it is
+ * associated with.
+ *
+ * This function expects the caller to protect the GEM's GPUVA list against
+ * concurrent access using the GEMs dma_resv lock.
+ */
+void
+drm_gpuva_link(struct drm_gpuva *va)
+{
+	struct drm_gem_object *obj = va->gem.obj;
+
+	if (unlikely(!obj))
+		return;
+
+	drm_gem_gpuva_assert_lock_held(obj);
+
+	list_add_tail(&va->gem.entry, &obj->gpuva.list);
+}
+EXPORT_SYMBOL_GPL(drm_gpuva_link);
+
+/**
+ * drm_gpuva_unlink() - unlink a &drm_gpuva
+ * @va: the &drm_gpuva to unlink
+ *
+ * This removes the given &va from the GPU VA list of the &drm_gem_object it is
+ * associated with.
+ *
+ * This function expects the caller to protect the GEM's GPUVA list against
+ * concurrent access using the GEMs dma_resv lock.
+ */
+void
+drm_gpuva_unlink(struct drm_gpuva *va)
+{
+	struct drm_gem_object *obj = va->gem.obj;
+
+	if (unlikely(!obj))
+		return;
+
+	drm_gem_gpuva_assert_lock_held(obj);
+
+	list_del_init(&va->gem.entry);
+}
+EXPORT_SYMBOL_GPL(drm_gpuva_unlink);
+
+/**
+ * drm_gpuva_find_first() - find the first &drm_gpuva in the given range
+ * @gpuvm: the &drm_gpuvm to search in
+ * @addr: the &drm_gpuvas address
+ * @range: the &drm_gpuvas range
+ *
+ * Returns: the first &drm_gpuva within the given range
+ */
+struct drm_gpuva *
+drm_gpuva_find_first(struct drm_gpuvm *gpuvm,
+		     u64 addr, u64 range)
+{
+	u64 last = addr + range - 1;
+
+	return drm_gpuva_it_iter_first(&gpuvm->rb.tree, addr, last);
+}
+EXPORT_SYMBOL_GPL(drm_gpuva_find_first);
+
+/**
+ * drm_gpuva_find() - find a &drm_gpuva
+ * @gpuvm: the &drm_gpuvm to search in
+ * @addr: the &drm_gpuvas address
+ * @range: the &drm_gpuvas range
+ *
+ * Returns: the &drm_gpuva at a given &addr and with a given &range
+ */
+struct drm_gpuva *
+drm_gpuva_find(struct drm_gpuvm *gpuvm,
+	       u64 addr, u64 range)
+{
+	struct drm_gpuva *va;
+
+	va = drm_gpuva_find_first(gpuvm, addr, range);
+	if (!va)
+		goto out;
+
+	if (va->va.addr != addr ||
+	    va->va.range != range)
+		goto out;
+
+	return va;
+
+out:
+	return NULL;
+}
+EXPORT_SYMBOL_GPL(drm_gpuva_find);
+
+/**
+ * drm_gpuva_find_prev() - find the &drm_gpuva before the given address
+ * @gpuvm: the &drm_gpuvm to search in
+ * @start: the given GPU VA's start address
+ *
+ * Find the adjacent &drm_gpuva before the GPU VA with given &start address.
+ *
+ * Note that if there is any free space between the GPU VA mappings no mapping
+ * is returned.
+ *
+ * Returns: a pointer to the found &drm_gpuva or NULL if none was found
+ */
+struct drm_gpuva *
+drm_gpuva_find_prev(struct drm_gpuvm *gpuvm, u64 start)
+{
+	if (!drm_gpuvm_range_valid(gpuvm, start - 1, 1))
+		return NULL;
+
+	return drm_gpuva_it_iter_first(&gpuvm->rb.tree, start - 1, start);
+}
+EXPORT_SYMBOL_GPL(drm_gpuva_find_prev);
+
+/**
+ * drm_gpuva_find_next() - find the &drm_gpuva after the given address
+ * @gpuvm: the &drm_gpuvm to search in
+ * @end: the given GPU VA's end address
+ *
+ * Find the adjacent &drm_gpuva after the GPU VA with given &end address.
+ *
+ * Note that if there is any free space between the GPU VA mappings no mapping
+ * is returned.
+ *
+ * Returns: a pointer to the found &drm_gpuva or NULL if none was found
+ */
+struct drm_gpuva *
+drm_gpuva_find_next(struct drm_gpuvm *gpuvm, u64 end)
+{
+	if (!drm_gpuvm_range_valid(gpuvm, end, 1))
+		return NULL;
+
+	return drm_gpuva_it_iter_first(&gpuvm->rb.tree, end, end + 1);
+}
+EXPORT_SYMBOL_GPL(drm_gpuva_find_next);
+
+/**
+ * drm_gpuvm_interval_empty() - indicate whether a given interval of the VA space
+ * is empty
+ * @gpuvm: the &drm_gpuvm to check the range for
+ * @addr: the start address of the range
+ * @range: the range of the interval
+ *
+ * Returns: true if the interval is empty, false otherwise
+ */
+bool
+drm_gpuvm_interval_empty(struct drm_gpuvm *gpuvm, u64 addr, u64 range)
+{
+	return !drm_gpuva_find_first(gpuvm, addr, range);
+}
+EXPORT_SYMBOL_GPL(drm_gpuvm_interval_empty);
+
+/**
+ * drm_gpuva_map() - helper to insert a &drm_gpuva according to a
+ * &drm_gpuva_op_map
+ * @gpuvm: the &drm_gpuvm
+ * @va: the &drm_gpuva to insert
+ * @op: the &drm_gpuva_op_map to initialize @va with
+ *
+ * Initializes the @va from the @op and inserts it into the given @gpuvm.
+ */
+void
+drm_gpuva_map(struct drm_gpuvm *gpuvm,
+	      struct drm_gpuva *va,
+	      struct drm_gpuva_op_map *op)
+{
+	drm_gpuva_init_from_op(va, op);
+	drm_gpuva_insert(gpuvm, va);
+}
+EXPORT_SYMBOL_GPL(drm_gpuva_map);
+
+/**
+ * drm_gpuva_remap() - helper to remap a &drm_gpuva according to a
+ * &drm_gpuva_op_remap
+ * @prev: the &drm_gpuva to remap when keeping the start of a mapping
+ * @next: the &drm_gpuva to remap when keeping the end of a mapping
+ * @op: the &drm_gpuva_op_remap to initialize @prev and @next with
+ *
+ * Removes the currently mapped &drm_gpuva and remaps it using @prev and/or
+ * @next.
+ */
+void
+drm_gpuva_remap(struct drm_gpuva *prev,
+		struct drm_gpuva *next,
+		struct drm_gpuva_op_remap *op)
+{
+	struct drm_gpuva *curr = op->unmap->va;
+	struct drm_gpuvm *gpuvm = curr->vm;
+
+	drm_gpuva_remove(curr);
+
+	if (op->prev) {
+		drm_gpuva_init_from_op(prev, op->prev);
+		drm_gpuva_insert(gpuvm, prev);
+	}
+
+	if (op->next) {
+		drm_gpuva_init_from_op(next, op->next);
+		drm_gpuva_insert(gpuvm, next);
+	}
+}
+EXPORT_SYMBOL_GPL(drm_gpuva_remap);
+
+/**
+ * drm_gpuva_unmap() - helper to remove a &drm_gpuva according to a
+ * &drm_gpuva_op_unmap
+ * @op: the &drm_gpuva_op_unmap specifying the &drm_gpuva to remove
+ *
+ * Removes the &drm_gpuva associated with the &drm_gpuva_op_unmap.
+ */
+void
+drm_gpuva_unmap(struct drm_gpuva_op_unmap *op)
+{
+	drm_gpuva_remove(op->va);
+}
+EXPORT_SYMBOL_GPL(drm_gpuva_unmap);
+
+static int
+op_map_cb(const struct drm_gpuvm_ops *fn, void *priv,
+	  u64 addr, u64 range,
+	  struct drm_gem_object *obj, u64 offset)
+{
+	struct drm_gpuva_op op = {};
+
+	op.op = DRM_GPUVA_OP_MAP;
+	op.map.va.addr = addr;
+	op.map.va.range = range;
+	op.map.gem.obj = obj;
+	op.map.gem.offset = offset;
+
+	return fn->sm_step_map(&op, priv);
+}
+
+static int
+op_remap_cb(const struct drm_gpuvm_ops *fn, void *priv,
+	    struct drm_gpuva_op_map *prev,
+	    struct drm_gpuva_op_map *next,
+	    struct drm_gpuva_op_unmap *unmap)
+{
+	struct drm_gpuva_op op = {};
+	struct drm_gpuva_op_remap *r;
+
+	op.op = DRM_GPUVA_OP_REMAP;
+	r = &op.remap;
+	r->prev = prev;
+	r->next = next;
+	r->unmap = unmap;
+
+	return fn->sm_step_remap(&op, priv);
+}
+
+static int
+op_unmap_cb(const struct drm_gpuvm_ops *fn, void *priv,
+	    struct drm_gpuva *va, bool merge)
+{
+	struct drm_gpuva_op op = {};
+
+	op.op = DRM_GPUVA_OP_UNMAP;
+	op.unmap.va = va;
+	op.unmap.keep = merge;
+
+	return fn->sm_step_unmap(&op, priv);
+}
+
+static int
+__drm_gpuvm_sm_map(struct drm_gpuvm *gpuvm,
+		   const struct drm_gpuvm_ops *ops, void *priv,
+		   u64 req_addr, u64 req_range,
+		   struct drm_gem_object *req_obj, u64 req_offset)
+{
+	struct drm_gpuva *va, *next, *prev = NULL;
+	u64 req_end = req_addr + req_range;
+	int ret;
+
+	if (unlikely(!drm_gpuvm_range_valid(gpuvm, req_addr, req_range)))
+		return -EINVAL;
+
+	drm_gpuvm_for_each_va_range_safe(va, next, gpuvm, req_addr, req_end) {
+		struct drm_gem_object *obj = va->gem.obj;
+		u64 offset = va->gem.offset;
+		u64 addr = va->va.addr;
+		u64 range = va->va.range;
+		u64 end = addr + range;
+		bool merge = !!va->gem.obj;
+
+		if (addr == req_addr) {
+			merge &= obj == req_obj &&
+				 offset == req_offset;
+
+			if (end == req_end) {
+				ret = op_unmap_cb(ops, priv, va, merge);
+				if (ret)
+					return ret;
+				break;
+			}
+
+			if (end < req_end) {
+				ret = op_unmap_cb(ops, priv, va, merge);
+				if (ret)
+					return ret;
+				goto next;
+			}
+
+			if (end > req_end) {
+				struct drm_gpuva_op_map n = {
+					.va.addr = req_end,
+					.va.range = range - req_range,
+					.gem.obj = obj,
+					.gem.offset = offset + req_range,
+				};
+				struct drm_gpuva_op_unmap u = {
+					.va = va,
+					.keep = merge,
+				};
+
+				ret = op_remap_cb(ops, priv, NULL, &n, &u);
+				if (ret)
+					return ret;
+				break;
+			}
+		} else if (addr < req_addr) {
+			u64 ls_range = req_addr - addr;
+			struct drm_gpuva_op_map p = {
+				.va.addr = addr,
+				.va.range = ls_range,
+				.gem.obj = obj,
+				.gem.offset = offset,
+			};
+			struct drm_gpuva_op_unmap u = { .va = va };
+
+			merge &= obj == req_obj &&
+				 offset + ls_range == req_offset;
+			u.keep = merge;
+
+			if (end == req_end) {
+				ret = op_remap_cb(ops, priv, &p, NULL, &u);
+				if (ret)
+					return ret;
+				break;
+			}
+
+			if (end < req_end) {
+				ret = op_remap_cb(ops, priv, &p, NULL, &u);
+				if (ret)
+					return ret;
+				goto next;
+			}
+
+			if (end > req_end) {
+				struct drm_gpuva_op_map n = {
+					.va.addr = req_end,
+					.va.range = end - req_end,
+					.gem.obj = obj,
+					.gem.offset = offset + ls_range +
+						      req_range,
+				};
+
+				ret = op_remap_cb(ops, priv, &p, &n, &u);
+				if (ret)
+					return ret;
+				break;
+			}
+		} else if (addr > req_addr) {
+			merge &= obj == req_obj &&
+				 offset == req_offset +
+					   (addr - req_addr);
+
+			if (end == req_end) {
+				ret = op_unmap_cb(ops, priv, va, merge);
+				if (ret)
+					return ret;
+				break;
+			}
+
+			if (end < req_end) {
+				ret = op_unmap_cb(ops, priv, va, merge);
+				if (ret)
+					return ret;
+				goto next;
+			}
+
+			if (end > req_end) {
+				struct drm_gpuva_op_map n = {
+					.va.addr = req_end,
+					.va.range = end - req_end,
+					.gem.obj = obj,
+					.gem.offset = offset + req_end - addr,
+				};
+				struct drm_gpuva_op_unmap u = {
+					.va = va,
+					.keep = merge,
+				};
+
+				ret = op_remap_cb(ops, priv, NULL, &n, &u);
+				if (ret)
+					return ret;
+				break;
+			}
+		}
+next:
+		prev = va;
+	}
+
+	return op_map_cb(ops, priv,
+			 req_addr, req_range,
+			 req_obj, req_offset);
+}
+
+static int
+__drm_gpuvm_sm_unmap(struct drm_gpuvm *gpuvm,
+		     const struct drm_gpuvm_ops *ops, void *priv,
+		     u64 req_addr, u64 req_range)
+{
+	struct drm_gpuva *va, *next;
+	u64 req_end = req_addr + req_range;
+	int ret;
+
+	if (unlikely(!drm_gpuvm_range_valid(gpuvm, req_addr, req_range)))
+		return -EINVAL;
+
+	drm_gpuvm_for_each_va_range_safe(va, next, gpuvm, req_addr, req_end) {
+		struct drm_gpuva_op_map prev = {}, next = {};
+		bool prev_split = false, next_split = false;
+		struct drm_gem_object *obj = va->gem.obj;
+		u64 offset = va->gem.offset;
+		u64 addr = va->va.addr;
+		u64 range = va->va.range;
+		u64 end = addr + range;
+
+		if (addr < req_addr) {
+			prev.va.addr = addr;
+			prev.va.range = req_addr - addr;
+			prev.gem.obj = obj;
+			prev.gem.offset = offset;
+
+			prev_split = true;
+		}
+
+		if (end > req_end) {
+			next.va.addr = req_end;
+			next.va.range = end - req_end;
+			next.gem.obj = obj;
+			next.gem.offset = offset + (req_end - addr);
+
+			next_split = true;
+		}
+
+		if (prev_split || next_split) {
+			struct drm_gpuva_op_unmap unmap = { .va = va };
+
+			ret = op_remap_cb(ops, priv,
+					  prev_split ? &prev : NULL,
+					  next_split ? &next : NULL,
+					  &unmap);
+			if (ret)
+				return ret;
+		} else {
+			ret = op_unmap_cb(ops, priv, va, false);
+			if (ret)
+				return ret;
+		}
+	}
+
+	return 0;
+}
+
+/**
+ * drm_gpuvm_sm_map() - creates the &drm_gpuva_op split/merge steps
+ * @gpuvm: the &drm_gpuvm representing the GPU VA space
+ * @req_addr: the start address of the new mapping
+ * @req_range: the range of the new mapping
+ * @req_obj: the &drm_gem_object to map
+ * @req_offset: the offset within the &drm_gem_object
+ * @priv: pointer to a driver private data structure
+ *
+ * This function iterates the given range of the GPU VA space. It utilizes the
+ * &drm_gpuvm_ops to call back into the driver providing the split and merge
+ * steps.
+ *
+ * Drivers may use these callbacks to update the GPU VA space right away within
+ * the callback. In case the driver decides to copy and store the operations for
+ * later processing neither this function nor &drm_gpuvm_sm_unmap is allowed to
+ * be called before the &drm_gpuvm's view of the GPU VA space was
+ * updated with the previous set of operations. To update the
+ * &drm_gpuvm's view of the GPU VA space drm_gpuva_insert(),
+ * drm_gpuva_destroy_locked() and/or drm_gpuva_destroy_unlocked() should be
+ * used.
+ *
+ * A sequence of callbacks can contain map, unmap and remap operations, but
+ * the sequence of callbacks might also be empty if no operation is required,
+ * e.g. if the requested mapping already exists in the exact same way.
+ *
+ * There can be an arbitrary amount of unmap operations, a maximum of two remap
+ * operations and a single map operation. The latter one represents the original
+ * map operation requested by the caller.
+ *
+ * Returns: 0 on success or a negative error code
+ */
+int
+drm_gpuvm_sm_map(struct drm_gpuvm *gpuvm, void *priv,
+		 u64 req_addr, u64 req_range,
+		 struct drm_gem_object *req_obj, u64 req_offset)
+{
+	const struct drm_gpuvm_ops *ops = gpuvm->ops;
+
+	if (unlikely(!(ops && ops->sm_step_map &&
+		       ops->sm_step_remap &&
+		       ops->sm_step_unmap)))
+		return -EINVAL;
+
+	return __drm_gpuvm_sm_map(gpuvm, ops, priv,
+				  req_addr, req_range,
+				  req_obj, req_offset);
+}
+EXPORT_SYMBOL_GPL(drm_gpuvm_sm_map);
+
+/**
+ * drm_gpuvm_sm_unmap() - creates the &drm_gpuva_ops to split on unmap
+ * @gpuvm: the &drm_gpuvm representing the GPU VA space
+ * @priv: pointer to a driver private data structure
+ * @req_addr: the start address of the range to unmap
+ * @req_range: the range of the mappings to unmap
+ *
+ * This function iterates the given range of the GPU VA space. It utilizes the
+ * &drm_gpuvm_ops to call back into the driver providing the operations to
+ * unmap and, if required, split existent mappings.
+ *
+ * Drivers may use these callbacks to update the GPU VA space right away within
+ * the callback. In case the driver decides to copy and store the operations for
+ * later processing neither this function nor &drm_gpuvm_sm_map is allowed to be
+ * called before the &drm_gpuvm's view of the GPU VA space was updated
+ * with the previous set of operations. To update the &drm_gpuvm's view
+ * of the GPU VA space drm_gpuva_insert(), drm_gpuva_destroy_locked() and/or
+ * drm_gpuva_destroy_unlocked() should be used.
+ *
+ * A sequence of callbacks can contain unmap and remap operations, depending on
+ * whether there are actual overlapping mappings to split.
+ *
+ * There can be an arbitrary amount of unmap operations and a maximum of two
+ * remap operations.
+ *
+ * Returns: 0 on success or a negative error code
+ */
+int
+drm_gpuvm_sm_unmap(struct drm_gpuvm *gpuvm, void *priv,
+		   u64 req_addr, u64 req_range)
+{
+	const struct drm_gpuvm_ops *ops = gpuvm->ops;
+
+	if (unlikely(!(ops && ops->sm_step_remap &&
+		       ops->sm_step_unmap)))
+		return -EINVAL;
+
+	return __drm_gpuvm_sm_unmap(gpuvm, ops, priv,
+				    req_addr, req_range);
+}
+EXPORT_SYMBOL_GPL(drm_gpuvm_sm_unmap);
+
+static struct drm_gpuva_op *
+gpuva_op_alloc(struct drm_gpuvm *gpuvm)
+{
+	const struct drm_gpuvm_ops *fn = gpuvm->ops;
+	struct drm_gpuva_op *op;
+
+	if (fn && fn->op_alloc)
+		op = fn->op_alloc();
+	else
+		op = kzalloc(sizeof(*op), GFP_KERNEL);
+
+	if (unlikely(!op))
+		return NULL;
+
+	return op;
+}
+
+static void
+gpuva_op_free(struct drm_gpuvm *gpuvm,
+	      struct drm_gpuva_op *op)
+{
+	const struct drm_gpuvm_ops *fn = gpuvm->ops;
+
+	if (fn && fn->op_free)
+		fn->op_free(op);
+	else
+		kfree(op);
+}
+
+static int
+drm_gpuva_sm_step(struct drm_gpuva_op *__op,
+		  void *priv)
+{
+	struct {
+		struct drm_gpuvm *vm;
+		struct drm_gpuva_ops *ops;
+	} *args = priv;
+	struct drm_gpuvm *gpuvm = args->vm;
+	struct drm_gpuva_ops *ops = args->ops;
+	struct drm_gpuva_op *op;
+
+	op = gpuva_op_alloc(gpuvm);
+	if (unlikely(!op))
+		goto err;
+
+	memcpy(op, __op, sizeof(*op));
+
+	if (op->op == DRM_GPUVA_OP_REMAP) {
+		struct drm_gpuva_op_remap *__r = &__op->remap;
+		struct drm_gpuva_op_remap *r = &op->remap;
+
+		r->unmap = kmemdup(__r->unmap, sizeof(*r->unmap),
+				   GFP_KERNEL);
+		if (unlikely(!r->unmap))
+			goto err_free_op;
+
+		if (__r->prev) {
+			r->prev = kmemdup(__r->prev, sizeof(*r->prev),
+					  GFP_KERNEL);
+			if (unlikely(!r->prev))
+				goto err_free_unmap;
+		}
+
+		if (__r->next) {
+			r->next = kmemdup(__r->next, sizeof(*r->next),
+					  GFP_KERNEL);
+			if (unlikely(!r->next))
+				goto err_free_prev;
+		}
+	}
+
+	list_add_tail(&op->entry, &ops->list);
+
+	return 0;
+
+err_free_unmap:
+	kfree(op->remap.unmap);
+err_free_prev:
+	kfree(op->remap.prev);
+err_free_op:
+	gpuva_op_free(gpuvm, op);
+err:
+	return -ENOMEM;
+}
+
+static const struct drm_gpuvm_ops gpuvm_list_ops = {
+	.sm_step_map = drm_gpuva_sm_step,
+	.sm_step_remap = drm_gpuva_sm_step,
+	.sm_step_unmap = drm_gpuva_sm_step,
+};
+
+/**
+ * drm_gpuvm_sm_map_ops_create() - creates the &drm_gpuva_ops to split and merge
+ * @gpuvm: the &drm_gpuvm representing the GPU VA space
+ * @req_addr: the start address of the new mapping
+ * @req_range: the range of the new mapping
+ * @req_obj: the &drm_gem_object to map
+ * @req_offset: the offset within the &drm_gem_object
+ *
+ * This function creates a list of operations to perform splitting and merging
+ * of existent mapping(s) with the newly requested one.
+ *
+ * The list can be iterated with &drm_gpuva_for_each_op and must be processed
+ * in the given order. It can contain map, unmap and remap operations, but it
+ * also can be empty if no operation is required, e.g. if the requested mapping
+ * already exists is the exact same way.
+ *
+ * There can be an arbitrary amount of unmap operations, a maximum of two remap
+ * operations and a single map operation. The latter one represents the original
+ * map operation requested by the caller.
+ *
+ * Note that before calling this function again with another mapping request it
+ * is necessary to update the &drm_gpuvm's view of the GPU VA space. The
+ * previously obtained operations must be either processed or abandoned. To
+ * update the &drm_gpuvm's view of the GPU VA space drm_gpuva_insert(),
+ * drm_gpuva_destroy_locked() and/or drm_gpuva_destroy_unlocked() should be
+ * used.
+ *
+ * After the caller finished processing the returned &drm_gpuva_ops, they must
+ * be freed with &drm_gpuva_ops_free.
+ *
+ * Returns: a pointer to the &drm_gpuva_ops on success, an ERR_PTR on failure
+ */
+struct drm_gpuva_ops *
+drm_gpuvm_sm_map_ops_create(struct drm_gpuvm *gpuvm,
+			    u64 req_addr, u64 req_range,
+			    struct drm_gem_object *req_obj, u64 req_offset)
+{
+	struct drm_gpuva_ops *ops;
+	struct {
+		struct drm_gpuvm *vm;
+		struct drm_gpuva_ops *ops;
+	} args;
+	int ret;
+
+	ops = kzalloc(sizeof(*ops), GFP_KERNEL);
+	if (unlikely(!ops))
+		return ERR_PTR(-ENOMEM);
+
+	INIT_LIST_HEAD(&ops->list);
+
+	args.vm = gpuvm;
+	args.ops = ops;
+
+	ret = __drm_gpuvm_sm_map(gpuvm, &gpuvm_list_ops, &args,
+				 req_addr, req_range,
+				 req_obj, req_offset);
+	if (ret)
+		goto err_free_ops;
+
+	return ops;
+
+err_free_ops:
+	drm_gpuva_ops_free(gpuvm, ops);
+	return ERR_PTR(ret);
+}
+EXPORT_SYMBOL_GPL(drm_gpuvm_sm_map_ops_create);
+
+/**
+ * drm_gpuvm_sm_unmap_ops_create() - creates the &drm_gpuva_ops to split on
+ * unmap
+ * @gpuvm: the &drm_gpuvm representing the GPU VA space
+ * @req_addr: the start address of the range to unmap
+ * @req_range: the range of the mappings to unmap
+ *
+ * This function creates a list of operations to perform unmapping and, if
+ * required, splitting of the mappings overlapping the unmap range.
+ *
+ * The list can be iterated with &drm_gpuva_for_each_op and must be processed
+ * in the given order. It can contain unmap and remap operations, depending on
+ * whether there are actual overlapping mappings to split.
+ *
+ * There can be an arbitrary amount of unmap operations and a maximum of two
+ * remap operations.
+ *
+ * Note that before calling this function again with another range to unmap it
+ * is necessary to update the &drm_gpuvm's view of the GPU VA space. The
+ * previously obtained operations must be processed or abandoned. To update the
+ * &drm_gpuvm's view of the GPU VA space drm_gpuva_insert(),
+ * drm_gpuva_destroy_locked() and/or drm_gpuva_destroy_unlocked() should be
+ * used.
+ *
+ * After the caller finished processing the returned &drm_gpuva_ops, they must
+ * be freed with &drm_gpuva_ops_free.
+ *
+ * Returns: a pointer to the &drm_gpuva_ops on success, an ERR_PTR on failure
+ */
+struct drm_gpuva_ops *
+drm_gpuvm_sm_unmap_ops_create(struct drm_gpuvm *gpuvm,
+			      u64 req_addr, u64 req_range)
+{
+	struct drm_gpuva_ops *ops;
+	struct {
+		struct drm_gpuvm *vm;
+		struct drm_gpuva_ops *ops;
+	} args;
+	int ret;
+
+	ops = kzalloc(sizeof(*ops), GFP_KERNEL);
+	if (unlikely(!ops))
+		return ERR_PTR(-ENOMEM);
+
+	INIT_LIST_HEAD(&ops->list);
+
+	args.vm = gpuvm;
+	args.ops = ops;
+
+	ret = __drm_gpuvm_sm_unmap(gpuvm, &gpuvm_list_ops, &args,
+				   req_addr, req_range);
+	if (ret)
+		goto err_free_ops;
+
+	return ops;
+
+err_free_ops:
+	drm_gpuva_ops_free(gpuvm, ops);
+	return ERR_PTR(ret);
+}
+EXPORT_SYMBOL_GPL(drm_gpuvm_sm_unmap_ops_create);
+
+/**
+ * drm_gpuvm_prefetch_ops_create() - creates the &drm_gpuva_ops to prefetch
+ * @gpuvm: the &drm_gpuvm representing the GPU VA space
+ * @addr: the start address of the range to prefetch
+ * @range: the range of the mappings to prefetch
+ *
+ * This function creates a list of operations to perform prefetching.
+ *
+ * The list can be iterated with &drm_gpuva_for_each_op and must be processed
+ * in the given order. It can contain prefetch operations.
+ *
+ * There can be an arbitrary amount of prefetch operations.
+ *
+ * After the caller finished processing the returned &drm_gpuva_ops, they must
+ * be freed with &drm_gpuva_ops_free.
+ *
+ * Returns: a pointer to the &drm_gpuva_ops on success, an ERR_PTR on failure
+ */
+struct drm_gpuva_ops *
+drm_gpuvm_prefetch_ops_create(struct drm_gpuvm *gpuvm,
+			      u64 addr, u64 range)
+{
+	struct drm_gpuva_ops *ops;
+	struct drm_gpuva_op *op;
+	struct drm_gpuva *va;
+	u64 end = addr + range;
+	int ret;
+
+	ops = kzalloc(sizeof(*ops), GFP_KERNEL);
+	if (!ops)
+		return ERR_PTR(-ENOMEM);
+
+	INIT_LIST_HEAD(&ops->list);
+
+	drm_gpuvm_for_each_va_range(va, gpuvm, addr, end) {
+		op = gpuva_op_alloc(gpuvm);
+		if (!op) {
+			ret = -ENOMEM;
+			goto err_free_ops;
+		}
+
+		op->op = DRM_GPUVA_OP_PREFETCH;
+		op->prefetch.va = va;
+		list_add_tail(&op->entry, &ops->list);
+	}
+
+	return ops;
+
+err_free_ops:
+	drm_gpuva_ops_free(gpuvm, ops);
+	return ERR_PTR(ret);
+}
+EXPORT_SYMBOL_GPL(drm_gpuvm_prefetch_ops_create);
+
+/**
+ * drm_gpuvm_gem_unmap_ops_create() - creates the &drm_gpuva_ops to unmap a GEM
+ * @gpuvm: the &drm_gpuvm representing the GPU VA space
+ * @obj: the &drm_gem_object to unmap
+ *
+ * This function creates a list of operations to perform unmapping for every
+ * GPUVA attached to a GEM.
+ *
+ * The list can be iterated with &drm_gpuva_for_each_op and consists out of an
+ * arbitrary amount of unmap operations.
+ *
+ * After the caller finished processing the returned &drm_gpuva_ops, they must
+ * be freed with &drm_gpuva_ops_free.
+ *
+ * It is the callers responsibility to protect the GEMs GPUVA list against
+ * concurrent access using the GEMs dma_resv lock.
+ *
+ * Returns: a pointer to the &drm_gpuva_ops on success, an ERR_PTR on failure
+ */
+struct drm_gpuva_ops *
+drm_gpuvm_gem_unmap_ops_create(struct drm_gpuvm *gpuvm,
+			       struct drm_gem_object *obj)
+{
+	struct drm_gpuva_ops *ops;
+	struct drm_gpuva_op *op;
+	struct drm_gpuva *va;
+	int ret;
+
+	drm_gem_gpuva_assert_lock_held(obj);
+
+	ops = kzalloc(sizeof(*ops), GFP_KERNEL);
+	if (!ops)
+		return ERR_PTR(-ENOMEM);
+
+	INIT_LIST_HEAD(&ops->list);
+
+	drm_gem_for_each_gpuva(va, obj) {
+		op = gpuva_op_alloc(gpuvm);
+		if (!op) {
+			ret = -ENOMEM;
+			goto err_free_ops;
+		}
+
+		op->op = DRM_GPUVA_OP_UNMAP;
+		op->unmap.va = va;
+		list_add_tail(&op->entry, &ops->list);
+	}
+
+	return ops;
+
+err_free_ops:
+	drm_gpuva_ops_free(gpuvm, ops);
+	return ERR_PTR(ret);
+}
+EXPORT_SYMBOL_GPL(drm_gpuvm_gem_unmap_ops_create);
+
+/**
+ * drm_gpuva_ops_free() - free the given &drm_gpuva_ops
+ * @gpuvm: the &drm_gpuvm the ops were created for
+ * @ops: the &drm_gpuva_ops to free
+ *
+ * Frees the given &drm_gpuva_ops structure including all the ops associated
+ * with it.
+ */
+void
+drm_gpuva_ops_free(struct drm_gpuvm *gpuvm,
+		   struct drm_gpuva_ops *ops)
+{
+	struct drm_gpuva_op *op, *next;
+
+	drm_gpuva_for_each_op_safe(op, next, ops) {
+		list_del(&op->entry);
+
+		if (op->op == DRM_GPUVA_OP_REMAP) {
+			kfree(op->remap.prev);
+			kfree(op->remap.next);
+			kfree(op->remap.unmap);
+		}
+
+		gpuva_op_free(gpuvm, op);
+	}
+
+	kfree(ops);
+}
+EXPORT_SYMBOL_GPL(drm_gpuva_ops_free);