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Message-ID: <Y88W3ukvv/nPz8e3@nvishwa1-DESK>
Date:   Mon, 23 Jan 2023 15:23:10 -0800
From:   Niranjana Vishwanathapura <niranjana.vishwanathapura@...el.com>
To:     Danilo Krummrich <dakr@...hat.com>
CC:     <daniel@...ll.ch>, <airlied@...hat.com>,
        <christian.koenig@....com>, <bskeggs@...hat.com>,
        <jason@...kstrand.net>, <tzimmermann@...e.de>,
        <mripard@...nel.org>, <corbet@....net>,
        <nouveau@...ts.freedesktop.org>, <linux-kernel@...r.kernel.org>,
        <dri-devel@...ts.freedesktop.org>, <linux-doc@...r.kernel.org>
Subject: Re: [PATCH drm-next 03/14] drm: manager to keep track of GPUs VA
 mappings

On Wed, Jan 18, 2023 at 07:12:45AM +0100, Danilo Krummrich wrote:
>This adds the infrastructure for a manager implementation to keep track
>of GPU virtual address (VA) mappings.
>
>New UAPIs, motivated by Vulkan sparse memory bindings graphics drivers
>start implementing, allow userspace applications to request multiple and
>arbitrary GPU VA mappings of buffer objects. The DRM GPU VA manager is
>intended to serve the following purposes in this context.
>
>1) Provide a dedicated range allocator to track GPU VA allocations and
>   mappings, making use of the drm_mm range allocator.
>
>2) Generically connect GPU VA mappings to their backing buffers, in
>   particular DRM GEM objects.
>
>3) Provide a common implementation to perform more complex mapping
>   operations on the GPU VA space. In particular splitting and merging
>   of GPU VA mappings, e.g. for intersecting mapping requests or partial
>   unmap requests.
>
>Idea-suggested-by: Dave Airlie <airlied@...hat.com>
>Signed-off-by: Danilo Krummrich <dakr@...hat.com>
>---
> Documentation/gpu/drm-mm.rst    |   31 +
> drivers/gpu/drm/Makefile        |    1 +
> drivers/gpu/drm/drm_gem.c       |    3 +
> drivers/gpu/drm/drm_gpuva_mgr.c | 1323 +++++++++++++++++++++++++++++++
> include/drm/drm_drv.h           |    6 +
> include/drm/drm_gem.h           |   75 ++
> include/drm/drm_gpuva_mgr.h     |  527 ++++++++++++
> 7 files changed, 1966 insertions(+)
> create mode 100644 drivers/gpu/drm/drm_gpuva_mgr.c
> create mode 100644 include/drm/drm_gpuva_mgr.h
>
>diff --git a/Documentation/gpu/drm-mm.rst b/Documentation/gpu/drm-mm.rst
>index a52e6f4117d6..c9f120cfe730 100644
>--- a/Documentation/gpu/drm-mm.rst
>+++ b/Documentation/gpu/drm-mm.rst
>@@ -466,6 +466,37 @@ DRM MM Range Allocator Function References
> .. kernel-doc:: drivers/gpu/drm/drm_mm.c
>    :export:
>
>+DRM GPU VA Manager
>+==================
>+
>+Overview
>+--------
>+
>+.. kernel-doc:: drivers/gpu/drm/drm_gpuva_mgr.c
>+   :doc: Overview
>+
>+Split and Merge
>+---------------
>+
>+.. kernel-doc:: drivers/gpu/drm/drm_gpuva_mgr.c
>+   :doc: Split and Merge
>+
>+Locking
>+-------
>+
>+.. kernel-doc:: drivers/gpu/drm/drm_gpuva_mgr.c
>+   :doc: Locking
>+
>+
>+DRM GPU VA Manager Function References
>+--------------------------------------
>+
>+.. kernel-doc:: include/drm/drm_gpuva_mgr.h
>+   :internal:
>+
>+.. kernel-doc:: drivers/gpu/drm/drm_gpuva_mgr.c
>+   :export:
>+
> DRM Buddy Allocator
> ===================
>
>diff --git a/drivers/gpu/drm/Makefile b/drivers/gpu/drm/Makefile
>index 4fe190aee584..de2ffca3b6e4 100644
>--- a/drivers/gpu/drm/Makefile
>+++ b/drivers/gpu/drm/Makefile
>@@ -45,6 +45,7 @@ drm-y := \
> 	drm_vblank.o \
> 	drm_vblank_work.o \
> 	drm_vma_manager.o \
>+	drm_gpuva_mgr.o \
> 	drm_writeback.o
> drm-$(CONFIG_DRM_LEGACY) += \
> 	drm_agpsupport.o \
>diff --git a/drivers/gpu/drm/drm_gem.c b/drivers/gpu/drm/drm_gem.c
>index 59a0bb5ebd85..65115fe88627 100644
>--- a/drivers/gpu/drm/drm_gem.c
>+++ b/drivers/gpu/drm/drm_gem.c
>@@ -164,6 +164,9 @@ void drm_gem_private_object_init(struct drm_device *dev,
> 	if (!obj->resv)
> 		obj->resv = &obj->_resv;
>
>+	if (drm_core_check_feature(dev, DRIVER_GEM_GPUVA))
>+		drm_gem_gpuva_init(obj);
>+
> 	drm_vma_node_reset(&obj->vma_node);
> 	INIT_LIST_HEAD(&obj->lru_node);
> }
>diff --git a/drivers/gpu/drm/drm_gpuva_mgr.c b/drivers/gpu/drm/drm_gpuva_mgr.c
>new file mode 100644
>index 000000000000..e665f642689d
>--- /dev/null
>+++ b/drivers/gpu/drm/drm_gpuva_mgr.c
>@@ -0,0 +1,1323 @@
>+// SPDX-License-Identifier: GPL-2.0
>+/*
>+ * 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@...hat.com>
>+ *
>+ */
>+
>+#include <drm/drm_gem.h>
>+#include <drm/drm_gpuva_mgr.h>
>+
>+/**
>+ * DOC: Overview
>+ *
>+ * The DRM GPU VA Manager, represented by struct drm_gpuva_manager 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 (and a corresponding list lock) of
>+ * &drm_gpuva objects representing all existent GPU VA mappings using this
>+ * &drm_gem_object as backing buffer.
>+ *
>+ * A GPU VA mapping can only be created within a previously allocated
>+ * &drm_gpuva_region, which represents a reserved portion of the GPU VA space.
>+ * GPU VA mappings are not allowed to span over a &drm_gpuva_region's boundary.
>+ *
>+ * GPU VA regions can also be flagged as sparse, which allows drivers to create
>+ * sparse mappings for a whole GPU VA region in order to support Vulkan
>+ * 'Sparse Resources'.
>+ *

So, is the sparse resources the only usecase for the VA region abstraction in uapi?
Or are there any other potential usecases (other than kernel reserved space)?

>+ * The GPU VA manager internally uses the &drm_mm range allocator to manage the
>+ * &drm_gpuva mappings and the &drm_gpuva_regions within a GPU's virtual address
>+ * space.
>+ *
>+ * Besides the GPU VA space regions (&drm_gpuva_region) allocated by a driver
>+ * the &drm_gpuva_manager contains a special region 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_gpuva_manager,
>+ * struct drm_gpuva_region and struct drm_gpuva within their own driver
>+ * specific structures, there won't be any memory allocations of it's own nor
>+ * memory allocations of &drm_gpuva or &drm_gpuva_region entries.
>+ */
>+
>+/**
>+ * DOC: Split and Merge
>+ *
>+ * The DRM GPU VA manager also 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.

Looks like the split and merge is only based on address continuity (virtual and
physical).
How about potential page table attributes specified during VM_BIND for a mapping
such as readonly, caching attributes, atomicity etc?

Thanks,
Niranjana

>+ *
>+ * Drivers can call drm_gpuva_sm_map_ops_create() to obtain a list of map, unmap
>+ * and remap operations for a given newly requested mapping. This list
>+ * 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_gpuva_ops contain an arbitrary amount of unmap
>+ * operations, a maximum of two remap operations and a single map operation.
>+ * The set of operations can also be empty if no operation is required, e.g. if
>+ * the requested mapping already exists in the exact same way.
>+ *
>+ * The single map operation, if existent, represents the original map operation
>+ * requested by the caller. Please note that this operation might be altered
>+ * comparing it with the original map operation, e.g. because it was merged with
>+ * an already  existent mapping. Hence, drivers must execute this map operation
>+ * instead of the original one they passed to drm_gpuva_sm_map_ops_create().
>+ *
>+ * &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_gpuva_manager'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.
>+ *
>+ * Generally, the DRM GPU VA manager never merges mappings across the
>+ * boundaries of &drm_gpuva_regions. This is the case since merging between
>+ * GPU VA regions would result into unmap and map operations to be issued for
>+ * both regions involved although the original mapping request was referred to
>+ * one specific GPU VA region only. Since the other GPU VA region, the one not
>+ * explicitly requested to be altered, might be in use by the GPU, we are not
>+ * allowed to issue any map/unmap operations for this region.
>+ *
>+ * Note that before calling drm_gpuva_sm_map_ops_create() again with another
>+ * mapping request it is necessary to update the &drm_gpuva_manager's view of
>+ * the GPU VA space. The previously obtained operations must be either fully
>+ * processed or completely abandoned.
>+ *
>+ * To update the &drm_gpuva_manager's view of the GPU VA space
>+ * drm_gpuva_insert(), drm_gpuva_destroy_locked() and/or
>+ * drm_gpuva_destroy_unlocked() should be used.
>+ *
>+ * Analogue to drm_gpuva_sm_map_ops_create() drm_gpuva_sm_unmap_ops_create()
>+ * provides drivers a the list of operations to be executed in order to unmap
>+ * a range of GPU VA space. The logic behind this functions 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.
>+ *
>+ * The following paragraph depicts the basic constellations of existent GPU VA
>+ * mappings, a newly requested mapping and the resulting mappings as implemented
>+ * by drm_gpuva_sm_map_ops_create()  - it doesn't cover arbitrary combinations
>+ * of those constellations.
>+ *
>+ * ::
>+ *
>+ *	1) Existent mapping is kept.
>+ *	----------------------------
>+ *
>+ *	     0     a     1
>+ *	old: |-----------| (bo_offset=n)
>+ *
>+ *	     0     a     1
>+ *	req: |-----------| (bo_offset=n)
>+ *
>+ *	     0     a     1
>+ *	new: |-----------| (bo_offset=n)
>+ *
>+ *
>+ *	2) Existent mapping is replaced.
>+ *	--------------------------------
>+ *
>+ *	     0     a     1
>+ *	old: |-----------| (bo_offset=n)
>+ *
>+ *	     0     a     1
>+ *	req: |-----------| (bo_offset=m)
>+ *
>+ *	     0     a     1
>+ *	new: |-----------| (bo_offset=m)
>+ *
>+ *
>+ *	3) Existent mapping is replaced.
>+ *	--------------------------------
>+ *
>+ *	     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 replaced.
>+ *	--------------------------------
>+ *
>+ *	     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 bo_offset.
>+ *
>+ *
>+ *	5) Existent mapping is split.
>+ *	-----------------------------
>+ *
>+ *	     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 kept.
>+ *	----------------------------
>+ *
>+ *	     0     a     2
>+ *	old: |-----------| (bo_offset=n)
>+ *
>+ *	     0  a  1
>+ *	req: |-----|       (bo_offset=n)
>+ *
>+ *	     0     a     2
>+ *	new: |-----------| (bo_offset=n)
>+ *
>+ *
>+ *	7) Existent mapping is split.
>+ *	-----------------------------
>+ *
>+ *	     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 kept.
>+ *	----------------------------
>+ *
>+ *	      0     a     2
>+ *	old: |-----------| (bo_offset=n)
>+ *
>+ *	           1  a  2
>+ *	req:       |-----| (bo_offset=n+1)
>+ *
>+ *	     0     a     2
>+ *	new: |-----------| (bo_offset=n)
>+ *
>+ *
>+ *	9) Existent mapping is split.
>+ *	-----------------------------
>+ *
>+ *	     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 merged.
>+ *	-------------------------------
>+ *
>+ *	     0     a     2
>+ *	old: |-----------|       (bo_offset=n)
>+ *
>+ *	           1     a     3
>+ *	req:       |-----------| (bo_offset=n+1)
>+ *
>+ *	     0        a        3
>+ *	new: |-----------------| (bo_offset=n)
>+ *
>+ *
>+ *	11) Existent mapping is split.
>+ *	------------------------------
>+ *
>+ *	     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) Existent mapping is kept.
>+ *	-----------------------------
>+ *
>+ *	     0        a        3
>+ *	old: |-----------------| (bo_offset=n)
>+ *
>+ *	           1  a  2
>+ *	req:       |-----|       (bo_offset=n+1)
>+ *
>+ *	     0        a        3
>+ *	old: |-----------------| (bo_offset=n)
>+ *
>+ *
>+ *	13) Existent mapping is replaced.
>+ *	---------------------------------
>+ *
>+ *	           1  a  2
>+ *	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.
>+ *
>+ *
>+ *	14) Existent mapping is replaced.
>+ *	---------------------------------
>+ *
>+ *	           1  a  2
>+ *	old:       |-----| (bo_offset=n)
>+ *
>+ *	     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 mapping is split.
>+ *	------------------------------
>+ *
>+ *	           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)
>+ *
>+ *
>+ *	16) Existent mappings are merged.
>+ *	---------------------------------
>+ *
>+ *	     0     a     1
>+ *	old: |-----------|                        (bo_offset=n)
>+ *
>+ *	                            2     a     3
>+ *	old':                       |-----------| (bo_offset=n+2)
>+ *
>+ *	                1     a     2
>+ *	req:            |-----------|             (bo_offset=n+1)
>+ *
>+ *	                      a
>+ *	new: |----------------------------------| (bo_offset=n)
>+ */
>+
>+/**
>+ * 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, destroying and iterating
>+ * &drm_gpuva and &drm_gpuva_region objects as well as generating split and merge
>+ * operations.
>+ *
>+ * The GPU VA manager does take care of the locking of the backing
>+ * &drm_gem_object buffers GPU VA lists though, unless the provided functions
>+ * documentation claims otherwise.
>+ */
>+
>+/**
>+ * drm_gpuva_manager_init - initialize a &drm_gpuva_manager
>+ * @mgr: pointer to the &drm_gpuva_manager 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
>+ *
>+ * The &drm_gpuva_manager must be initialized with this function before use.
>+ *
>+ * Note that @mgr must be cleared to 0 before calling this function. The given
>+ * &name is expected to be managed by the surrounding driver structures.
>+ */
>+void
>+drm_gpuva_manager_init(struct drm_gpuva_manager *mgr,
>+		       const char *name,
>+		       u64 start_offset, u64 range,
>+		       u64 reserve_offset, u64 reserve_range)
>+{
>+	drm_mm_init(&mgr->va_mm, start_offset, range);
>+	drm_mm_init(&mgr->region_mm, start_offset, range);
>+
>+	mgr->mm_start = start_offset;
>+	mgr->mm_range = range;
>+
>+	mgr->name = name ? name : "unknown";
>+
>+	memset(&mgr->kernel_alloc_node, 0, sizeof(struct drm_mm_node));
>+	mgr->kernel_alloc_node.start = reserve_offset;
>+	mgr->kernel_alloc_node.size = reserve_range;
>+	drm_mm_reserve_node(&mgr->region_mm, &mgr->kernel_alloc_node);
>+}
>+EXPORT_SYMBOL(drm_gpuva_manager_init);
>+
>+/**
>+ * drm_gpuva_manager_destroy - cleanup a &drm_gpuva_manager
>+ * @mgr: pointer to the &drm_gpuva_manager to clean up
>+ *
>+ * Note that it is a bug to call this function on a manager that still
>+ * holds GPU VA mappings.
>+ */
>+void
>+drm_gpuva_manager_destroy(struct drm_gpuva_manager *mgr)
>+{
>+	mgr->name = NULL;
>+	drm_mm_remove_node(&mgr->kernel_alloc_node);
>+	drm_mm_takedown(&mgr->va_mm);
>+	drm_mm_takedown(&mgr->region_mm);
>+}
>+EXPORT_SYMBOL(drm_gpuva_manager_destroy);
>+
>+static struct drm_gpuva_region *
>+drm_gpuva_in_region(struct drm_gpuva_manager *mgr, u64 addr, u64 range)
>+{
>+	struct drm_gpuva_region *reg;
>+
>+	/* Find the VA region the requested range is strictly enclosed by. */
>+	drm_gpuva_for_each_region_in_range(reg, mgr, addr, addr + range) {
>+		if (reg->node.start <= addr &&
>+		    reg->node.start + reg->node.size >= addr + range &&
>+		    &reg->node != &mgr->kernel_alloc_node)
>+			return reg;
>+	}
>+
>+	return NULL;
>+}
>+
>+static bool
>+drm_gpuva_in_any_region(struct drm_gpuva_manager *mgr, u64 addr, u64 range)
>+{
>+	return !!drm_gpuva_in_region(mgr, addr, range);
>+}
>+
>+/**
>+ * drm_gpuva_insert - insert a &drm_gpuva
>+ * @mgr: the &drm_gpuva_manager to insert the &drm_gpuva in
>+ * @va: the &drm_gpuva to insert
>+ * @addr: the start address of the GPU VA
>+ * @range: the range of the GPU VA
>+ *
>+ * Insert a &drm_gpuva with a given address and range into a
>+ * &drm_gpuva_manager.
>+ *
>+ * The function assumes the caller does not hold the &drm_gem_object's
>+ * GPU VA list mutex.
>+ *
>+ * Returns: 0 on success, negative error code on failure.
>+ */
>+int
>+drm_gpuva_insert(struct drm_gpuva_manager *mgr,
>+		 struct drm_gpuva *va,
>+		 u64 addr, u64 range)
>+{
>+	struct drm_gpuva_region *reg;
>+	int ret;
>+
>+	if (!va->gem.obj)
>+		return -EINVAL;
>+
>+	reg = drm_gpuva_in_region(mgr, addr, range);
>+	if (!reg)
>+		return -EINVAL;
>+
>+	ret = drm_mm_insert_node_in_range(&mgr->va_mm, &va->node,
>+					  range, 0,
>+					  0, addr,
>+					  addr + range,
>+					  DRM_MM_INSERT_LOW|DRM_MM_INSERT_ONCE);
>+	if (ret)
>+		return ret;
>+
>+	va->mgr = mgr;
>+	va->region = reg;
>+
>+	return 0;
>+}
>+EXPORT_SYMBOL(drm_gpuva_insert);
>+
>+/**
>+ * drm_gpuva_link_locked - 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.
>+ *
>+ * The function assumes the caller already holds the &drm_gem_object's
>+ * GPU VA list mutex.
>+ */
>+void
>+drm_gpuva_link_locked(struct drm_gpuva *va)
>+{
>+	lockdep_assert_held(&va->gem.obj->gpuva.mutex);
>+	list_add_tail(&va->head, &va->gem.obj->gpuva.list);
>+}
>+EXPORT_SYMBOL(drm_gpuva_link_locked);
>+
>+/**
>+ * drm_gpuva_link_unlocked - unlink a &drm_gpuva
>+ * @va: the &drm_gpuva to unlink
>+ *
>+ * This adds the given &va to the GPU VA list of the &drm_gem_object it is
>+ * associated with.
>+ *
>+ * The function assumes the caller does not hold the &drm_gem_object's
>+ * GPU VA list mutex.
>+ */
>+void
>+drm_gpuva_link_unlocked(struct drm_gpuva *va)
>+{
>+	drm_gem_gpuva_lock(va->gem.obj);
>+	drm_gpuva_link_locked(va);
>+	drm_gem_gpuva_unlock(va->gem.obj);
>+}
>+EXPORT_SYMBOL(drm_gpuva_link_unlocked);
>+
>+/**
>+ * drm_gpuva_unlink_locked - 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.
>+ *
>+ * The function assumes the caller already holds the &drm_gem_object's
>+ * GPU VA list mutex.
>+ */
>+void
>+drm_gpuva_unlink_locked(struct drm_gpuva *va)
>+{
>+	lockdep_assert_held(&va->gem.obj->gpuva.mutex);
>+	list_del_init(&va->head);
>+}
>+EXPORT_SYMBOL(drm_gpuva_unlink_locked);
>+
>+/**
>+ * drm_gpuva_unlink_unlocked - 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.
>+ *
>+ * The function assumes the caller does not hold the &drm_gem_object's
>+ * GPU VA list mutex.
>+ */
>+void
>+drm_gpuva_unlink_unlocked(struct drm_gpuva *va)
>+{
>+	drm_gem_gpuva_lock(va->gem.obj);
>+	drm_gpuva_unlink_locked(va);
>+	drm_gem_gpuva_unlock(va->gem.obj);
>+}
>+EXPORT_SYMBOL(drm_gpuva_unlink_unlocked);
>+
>+/**
>+ * drm_gpuva_destroy_locked - destroy a &drm_gpuva
>+ * @va: the &drm_gpuva to destroy
>+ *
>+ * This removes the given &va from GPU VA list of the &drm_gem_object it is
>+ * associated with and removes it from the underlaying range allocator.
>+ *
>+ * The function assumes the caller already holds the &drm_gem_object's
>+ * GPU VA list mutex.
>+ */
>+void
>+drm_gpuva_destroy_locked(struct drm_gpuva *va)
>+{
>+	lockdep_assert_held(&va->gem.obj->gpuva.mutex);
>+
>+	list_del(&va->head);
>+	drm_mm_remove_node(&va->node);
>+}
>+EXPORT_SYMBOL(drm_gpuva_destroy_locked);
>+
>+/**
>+ * drm_gpuva_destroy_unlocked - destroy a &drm_gpuva
>+ * @va: the &drm_gpuva to destroy
>+ *
>+ * This removes the given &va from GPU VA list of the &drm_gem_object it is
>+ * associated with and removes it from the underlaying range allocator.
>+ *
>+ * The function assumes the caller does not hold the &drm_gem_object's
>+ * GPU VA list mutex.
>+ */
>+void
>+drm_gpuva_destroy_unlocked(struct drm_gpuva *va)
>+{
>+	drm_gem_gpuva_lock(va->gem.obj);
>+	list_del(&va->head);
>+	drm_gem_gpuva_unlock(va->gem.obj);
>+
>+	drm_mm_remove_node(&va->node);
>+}
>+EXPORT_SYMBOL(drm_gpuva_destroy_unlocked);
>+
>+/**
>+ * drm_gpuva_find - find a &drm_gpuva
>+ * @mgr: the &drm_gpuva_manager 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_gpuva_manager *mgr,
>+	       u64 addr, u64 range)
>+{
>+	struct drm_gpuva *va;
>+
>+	drm_gpuva_for_each_va_in_range(va, mgr, addr, range) {
>+		if (va->node.start == addr &&
>+		    va->node.size == range)
>+			return va;
>+	}
>+
>+	return NULL;
>+}
>+EXPORT_SYMBOL(drm_gpuva_find);
>+
>+/**
>+ * drm_gpuva_find_prev - find the &drm_gpuva before the given address
>+ * @mgr: the &drm_gpuva_manager 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_gpuva_manager *mgr, u64 start)
>+{
>+	struct drm_mm_node *node;
>+
>+	if (start <= mgr->mm_start ||
>+	    start > (mgr->mm_start + mgr->mm_range))
>+		return NULL;
>+
>+	node = __drm_mm_interval_first(&mgr->va_mm, start - 1, start);
>+	if (node == &mgr->va_mm.head_node)
>+		return NULL;
>+
>+	return (struct drm_gpuva *)node;
>+}
>+EXPORT_SYMBOL(drm_gpuva_find_prev);
>+
>+/**
>+ * drm_gpuva_find_next - find the &drm_gpuva after the given address
>+ * @mgr: the &drm_gpuva_manager 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_gpuva_manager *mgr, u64 end)
>+{
>+	struct drm_mm_node *node;
>+
>+	if (end < mgr->mm_start ||
>+	    end >= (mgr->mm_start + mgr->mm_range))
>+		return NULL;
>+
>+	node = __drm_mm_interval_first(&mgr->va_mm, end, end + 1);
>+	if (node == &mgr->va_mm.head_node)
>+		return NULL;
>+
>+	return (struct drm_gpuva *)node;
>+}
>+EXPORT_SYMBOL(drm_gpuva_find_next);
>+
>+/**
>+ * drm_gpuva_region_insert - insert a &drm_gpuva_region
>+ * @mgr: the &drm_gpuva_manager to insert the &drm_gpuva in
>+ * @reg: the &drm_gpuva_region to insert
>+ * @addr: the start address of the GPU VA
>+ * @range: the range of the GPU VA
>+ *
>+ * Insert a &drm_gpuva_region with a given address and range into a
>+ * &drm_gpuva_manager.
>+ *
>+ * Returns: 0 on success, negative error code on failure.
>+ */
>+int
>+drm_gpuva_region_insert(struct drm_gpuva_manager *mgr,
>+			struct drm_gpuva_region *reg,
>+			u64 addr, u64 range)
>+{
>+	int ret;
>+
>+	ret = drm_mm_insert_node_in_range(&mgr->region_mm, &reg->node,
>+					  range, 0,
>+					  0, addr,
>+					  addr + range,
>+					  DRM_MM_INSERT_LOW|
>+					  DRM_MM_INSERT_ONCE);
>+	if (ret)
>+		return ret;
>+
>+	reg->mgr = mgr;
>+
>+	return 0;
>+}
>+EXPORT_SYMBOL(drm_gpuva_region_insert);
>+
>+/**
>+ * drm_gpuva_region_destroy - destroy a &drm_gpuva_region
>+ * @mgr: the &drm_gpuva_manager holding the region
>+ * @reg: the &drm_gpuva to destroy
>+ *
>+ * This removes the given &reg from the underlaying range allocator.
>+ */
>+void
>+drm_gpuva_region_destroy(struct drm_gpuva_manager *mgr,
>+			 struct drm_gpuva_region *reg)
>+{
>+	struct drm_gpuva *va;
>+
>+	drm_gpuva_for_each_va_in_range(va, mgr,
>+				       reg->node.start,
>+				       reg->node.size) {
>+		WARN(1, "GPU VA region must be empty on destroy.\n");
>+		return;
>+	}
>+
>+	if (&reg->node == &mgr->kernel_alloc_node) {
>+		WARN(1, "Can't destroy kernel reserved region.\n");
>+		return;
>+	}
>+
>+	drm_mm_remove_node(&reg->node);
>+}
>+EXPORT_SYMBOL(drm_gpuva_region_destroy);
>+
>+/**
>+ * drm_gpuva_region_find - find a &drm_gpuva_region
>+ * @mgr: the &drm_gpuva_manager to search in
>+ * @addr: the &drm_gpuva_regions address
>+ * @range: the &drm_gpuva_regions range
>+ *
>+ * Returns: the &drm_gpuva_region at a given &addr and with a given &range
>+ */
>+struct drm_gpuva_region *
>+drm_gpuva_region_find(struct drm_gpuva_manager *mgr,
>+		      u64 addr, u64 range)
>+{
>+	struct drm_gpuva_region *reg;
>+
>+	drm_gpuva_for_each_region_in_range(reg, mgr, addr, addr + range)
>+		if (reg->node.start == addr &&
>+		    reg->node.size == range)
>+			return reg;
>+
>+	return NULL;
>+}
>+EXPORT_SYMBOL(drm_gpuva_region_find);
>+
>+static int
>+gpuva_op_map_new(struct drm_gpuva_op **pop,
>+		 u64 addr, u64 range,
>+		 struct drm_gem_object *obj, u64 offset)
>+{
>+	struct drm_gpuva_op *op;
>+
>+	op = *pop = kzalloc(sizeof(*op), GFP_KERNEL);
>+	if (!op)
>+		return -ENOMEM;
>+
>+	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 0;
>+}
>+
>+static int
>+gpuva_op_remap_new(struct drm_gpuva_op **pop,
>+		   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 = *pop = kzalloc(sizeof(*op), GFP_KERNEL);
>+	if (!op)
>+		return -ENOMEM;
>+
>+	op->op = DRM_GPUVA_OP_REMAP;
>+	r = &op->remap;
>+
>+	if (prev) {
>+		r->prev = kmemdup(prev, sizeof(*prev), GFP_KERNEL);
>+		if (!r->prev)
>+			goto err_free_op;
>+	}
>+
>+	if (next) {
>+		r->next = kmemdup(next, sizeof(*next), GFP_KERNEL);
>+		if (!r->next)
>+			goto err_free_prev;
>+	}
>+
>+	r->unmap = kmemdup(unmap, sizeof(*unmap), GFP_KERNEL);
>+	if (!r->unmap)
>+		goto err_free_next;
>+
>+	return 0;
>+
>+err_free_next:
>+	if (next)
>+		kfree(r->next);
>+err_free_prev:
>+	if (prev)
>+		kfree(r->prev);
>+err_free_op:
>+	kfree(op);
>+	*pop = NULL;
>+
>+	return -ENOMEM;
>+}
>+
>+static int
>+gpuva_op_unmap_new(struct drm_gpuva_op **pop,
>+		   struct drm_gpuva *va, bool merge)
>+{
>+	struct drm_gpuva_op *op;
>+
>+	op = *pop = kzalloc(sizeof(*op), GFP_KERNEL);
>+	if (!op)
>+		return -ENOMEM;
>+
>+	op->op = DRM_GPUVA_OP_UNMAP;
>+	op->unmap.va = va;
>+	op->unmap.keep = merge;
>+
>+	return 0;
>+}
>+
>+#define op_map_new_to_list(_ops, _addr, _range,		\
>+			   _obj, _offset)		\
>+do {							\
>+	struct drm_gpuva_op *op;			\
>+							\
>+	ret = gpuva_op_map_new(&op, _addr, _range,	\
>+			       _obj, _offset);		\
>+	if (ret)					\
>+		goto err_free_ops;			\
>+							\
>+	list_add_tail(&op->entry, _ops);		\
>+} while (0)
>+
>+#define op_remap_new_to_list(_ops, _prev, _next,	\
>+			     _unmap)			\
>+do {							\
>+	struct drm_gpuva_op *op;			\
>+							\
>+	ret = gpuva_op_remap_new(&op, _prev, _next,	\
>+				 _unmap);		\
>+	if (ret)					\
>+		goto err_free_ops;			\
>+							\
>+	list_add_tail(&op->entry, _ops);		\
>+} while (0)
>+
>+#define op_unmap_new_to_list(_ops, _gpuva, _merge)	\
>+do {							\
>+	struct drm_gpuva_op *op;			\
>+							\
>+	ret = gpuva_op_unmap_new(&op, _gpuva, _merge);	\
>+	if (ret)					\
>+		goto err_free_ops;			\
>+							\
>+	list_add_tail(&op->entry, _ops);		\
>+} while (0)
>+
>+/**
>+ * drm_gpuva_sm_map_ops_create - creates the &drm_gpuva_ops to split and merge
>+ * @mgr: the &drm_gpuva_manager 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, if existent,
>+ * represents the original map operation requested by the caller. Please note
>+ * that the map operation might has been modified, e.g. if it was
>+ * merged with an existent mapping.
>+ *
>+ * Note that before calling this function again with another mapping request it
>+ * is necessary to update the &drm_gpuva_manager's view of the GPU VA space.
>+ * The previously obtained operations must be either processed or abandoned.
>+ * To update the &drm_gpuva_manager'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_gpuva_sm_map_ops_create(struct drm_gpuva_manager *mgr,
>+			    u64 req_addr, u64 req_range,
>+			    struct drm_gem_object *req_obj, u64 req_offset)
>+{
>+	struct drm_gpuva_ops *ops;
>+	struct drm_gpuva *va, *prev = NULL;
>+	u64 req_end = req_addr + req_range;
>+	bool skip_pmerge = false, skip_nmerge = false;
>+	int ret;
>+
>+	if (!drm_gpuva_in_any_region(mgr, req_addr, req_range))
>+		return ERR_PTR(-EINVAL);
>+
>+	ops = kzalloc(sizeof(*ops), GFP_KERNEL);
>+	if (!ops)
>+		return ERR_PTR(-ENOMEM);
>+
>+	INIT_LIST_HEAD(&ops->list);
>+
>+	drm_gpuva_for_each_va_in_range(va, mgr, req_addr, req_end) {
>+		struct drm_gem_object *obj = va->gem.obj;
>+		u64 offset = va->gem.offset;
>+		u64 addr = va->node.start;
>+		u64 range = va->node.size;
>+		u64 end = addr + range;
>+
>+		/* Generally, we want to skip merging with potential mappings
>+		 * left and right of the requested one when we found a
>+		 * collision, since merging happens in this loop already.
>+		 *
>+		 * However, there is one exception when the requested mapping
>+		 * spans into a free VM area. If this is the case we might
>+		 * still hit the boundary of another mapping before and/or
>+		 * after the free VM area.
>+		 */
>+		skip_pmerge = true;
>+		skip_nmerge = true;
>+
>+		if (addr == req_addr) {
>+			bool merge = obj == req_obj &&
>+				     offset == req_offset;
>+			if (end == req_end) {
>+				if (merge)
>+					goto done;
>+
>+				op_unmap_new_to_list(&ops->list, va, false);
>+				break;
>+			}
>+
>+			if (end < req_end) {
>+				skip_nmerge = false;
>+				op_unmap_new_to_list(&ops->list, va, merge);
>+				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 };
>+
>+				if (merge)
>+					goto done;
>+
>+				op_remap_new_to_list(&ops->list, NULL, &n, &u);
>+				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 };
>+			bool merge = obj == req_obj &&
>+				     offset + ls_range == req_offset;
>+
>+			if (end == req_end) {
>+				if (merge)
>+					goto done;
>+
>+				op_remap_new_to_list(&ops->list, &p, NULL, &u);
>+				break;
>+			}
>+
>+			if (end < req_end) {
>+				u64 new_addr = addr;
>+				u64 new_range = req_range + ls_range;
>+				u64 new_offset = offset;
>+
>+				/* We validated that the requested mapping is
>+				 * within a single VA region already.
>+				 * Since it overlaps the current mapping (which
>+				 * can't cross a VA region boundary) we can be
>+				 * sure that we're still within the boundaries
>+				 * of the same VA region after merging.
>+				 */
>+				if (merge) {
>+					req_offset = new_offset;
>+					req_addr = new_addr;
>+					req_range = new_range;
>+					op_unmap_new_to_list(&ops->list, va, true);
>+					goto next;
>+				}
>+
>+				op_remap_new_to_list(&ops->list, &p, NULL, &u);
>+				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,
>+				};
>+
>+				if (merge)
>+					goto done;
>+
>+				op_remap_new_to_list(&ops->list, &p, &n, &u);
>+				break;
>+			}
>+		} else if (addr > req_addr) {
>+			bool merge = obj == req_obj &&
>+				     offset == req_offset +
>+					       (addr - req_addr);
>+			if (!prev)
>+				skip_pmerge = false;
>+
>+			if (end == req_end) {
>+				op_unmap_new_to_list(&ops->list, va, merge);
>+				break;
>+			}
>+
>+			if (end < req_end) {
>+				skip_nmerge = false;
>+				op_unmap_new_to_list(&ops->list, va, merge);
>+				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 };
>+				u64 new_end = end;
>+				u64 new_range = new_end - req_addr;
>+
>+				/* We validated that the requested mapping is
>+				 * within a single VA region already.
>+				 * Since it overlaps the current mapping (which
>+				 * can't cross a VA region boundary) we can be
>+				 * sure that we're still within the boundaries
>+				 * of the same VA region after merging.
>+				 */
>+				if (merge) {
>+					req_end = new_end;
>+					req_range = new_range;
>+					op_unmap_new_to_list(&ops->list, va, true);
>+					break;
>+				}
>+
>+				op_remap_new_to_list(&ops->list, NULL, &n, &u);
>+				break;
>+			}
>+		}
>+next:
>+		prev = va;
>+	}
>+
>+	va = skip_pmerge ? NULL : drm_gpuva_find_prev(mgr, req_addr);
>+	if (va) {
>+		struct drm_gem_object *obj = va->gem.obj;
>+		u64 offset = va->gem.offset;
>+		u64 addr = va->node.start;
>+		u64 range = va->node.size;
>+		u64 new_offset = offset;
>+		u64 new_addr = addr;
>+		u64 new_range = req_range + range;
>+		bool merge = obj == req_obj &&
>+			     offset + range == req_offset;
>+
>+		/* Don't merge over VA region boundaries. */
>+		merge &= drm_gpuva_in_any_region(mgr, new_addr, new_range);
>+		if (merge) {
>+			op_unmap_new_to_list(&ops->list, va, true);
>+
>+			req_offset = new_offset;
>+			req_addr = new_addr;
>+			req_range = new_range;
>+		}
>+	}
>+
>+	va = skip_nmerge ? NULL : drm_gpuva_find_next(mgr, req_end);
>+	if (va) {
>+		struct drm_gem_object *obj = va->gem.obj;
>+		u64 offset = va->gem.offset;
>+		u64 addr = va->node.start;
>+		u64 range = va->node.size;
>+		u64 end = addr + range;
>+		u64 new_range = req_range + range;
>+		u64 new_end = end;
>+		bool merge = obj == req_obj &&
>+			     offset == req_offset + req_range;
>+
>+		/* Don't merge over VA region boundaries. */
>+		merge &= drm_gpuva_in_any_region(mgr, req_addr, new_range);
>+		if (merge) {
>+			op_unmap_new_to_list(&ops->list, va, true);
>+
>+			req_range = new_range;
>+			req_end = new_end;
>+		}
>+	}
>+
>+	op_map_new_to_list(&ops->list,
>+			   req_addr, req_range,
>+			   req_obj, req_offset);
>+
>+done:
>+	return ops;
>+
>+err_free_ops:
>+	drm_gpuva_ops_free(ops);
>+	return ERR_PTR(ret);
>+}
>+EXPORT_SYMBOL(drm_gpuva_sm_map_ops_create);
>+
>+#undef op_map_new_to_list
>+#undef op_remap_new_to_list
>+#undef op_unmap_new_to_list
>+
>+/**
>+ * drm_gpuva_sm_unmap_ops_create - creates the &drm_gpuva_ops to split on unmap
>+ * @mgr: the &drm_gpuva_manager 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_gpuva_manager's view of the GPU VA space.
>+ * The previously obtained operations must be processed or abandoned.
>+ * To update the &drm_gpuva_manager'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_gpuva_sm_unmap_ops_create(struct drm_gpuva_manager *mgr,
>+			      u64 req_addr, u64 req_range)
>+{
>+	struct drm_gpuva_ops *ops;
>+	struct drm_gpuva_op *op;
>+	struct drm_gpuva_op_remap *r;
>+	struct drm_gpuva *va;
>+	u64 req_end = req_addr + req_range;
>+	int ret;
>+
>+	ops = kzalloc(sizeof(*ops), GFP_KERNEL);
>+	if (!ops)
>+		return ERR_PTR(-ENOMEM);
>+
>+	INIT_LIST_HEAD(&ops->list);
>+
>+	drm_gpuva_for_each_va_in_range(va, mgr, req_addr, req_end) {
>+		struct drm_gem_object *obj = va->gem.obj;
>+		u64 offset = va->gem.offset;
>+		u64 addr = va->node.start;
>+		u64 range = va->node.size;
>+		u64 end = addr + range;
>+
>+		op = kzalloc(sizeof(*op), GFP_KERNEL);
>+		if (!op) {
>+			ret = -ENOMEM;
>+			goto err_free_ops;
>+		}
>+
>+		r = &op->remap;
>+
>+		if (addr < req_addr) {
>+			r->prev = kzalloc(sizeof(*r->prev), GFP_KERNEL);
>+			if (!r->prev) {
>+				ret = -ENOMEM;
>+				goto err_free_op;
>+			}
>+
>+			r->prev->va.addr = addr;
>+			r->prev->va.range = req_addr - addr;
>+			r->prev->gem.obj = obj;
>+			r->prev->gem.offset = offset;
>+		}
>+
>+		if (end > req_end) {
>+			r->next = kzalloc(sizeof(*r->next), GFP_KERNEL);
>+			if (!r->next) {
>+				ret = -ENOMEM;
>+				goto err_free_prev;
>+			}
>+
>+			r->next->va.addr = req_end;
>+			r->next->va.range = end - req_end;
>+			r->next->gem.obj = obj;
>+			r->next->gem.offset = offset + (req_end - addr);
>+		}
>+
>+		if (op->remap.prev || op->remap.next) {
>+			op->op = DRM_GPUVA_OP_REMAP;
>+			r->unmap = kzalloc(sizeof(*r->unmap), GFP_KERNEL);
>+			if (!r->unmap) {
>+				ret = -ENOMEM;
>+				goto err_free_next;
>+			}
>+
>+			r->unmap->va = va;
>+		} else {
>+			op->op = DRM_GPUVA_OP_UNMAP;
>+			op->unmap.va = va;
>+		}
>+
>+		list_add_tail(&op->entry, &ops->list);
>+	}
>+
>+	return ops;
>+
>+err_free_next:
>+	if (r->next)
>+		kfree(r->next);
>+err_free_prev:
>+	if (r->prev)
>+		kfree(r->prev);
>+err_free_op:
>+	kfree(op);
>+err_free_ops:
>+	drm_gpuva_ops_free(ops);
>+	return ERR_PTR(ret);
>+}
>+EXPORT_SYMBOL(drm_gpuva_sm_unmap_ops_create);
>+
>+/**
>+ * drm_gpuva_ops_free - free the given &drm_gpuva_ops
>+ * @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_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) {
>+			if (op->remap.prev)
>+				kfree(op->remap.prev);
>+
>+			if (op->remap.next)
>+				kfree(op->remap.next);
>+
>+			kfree(op->remap.unmap);
>+		}
>+		kfree(op);
>+	}
>+
>+	kfree(ops);
>+}
>+EXPORT_SYMBOL(drm_gpuva_ops_free);
>diff --git a/include/drm/drm_drv.h b/include/drm/drm_drv.h
>index d7c521e8860f..6feacd93aca6 100644
>--- a/include/drm/drm_drv.h
>+++ b/include/drm/drm_drv.h
>@@ -104,6 +104,12 @@ enum drm_driver_feature {
> 	 * acceleration should be handled by two drivers that are connected using auxiliary bus.
> 	 */
> 	DRIVER_COMPUTE_ACCEL            = BIT(7),
>+	/**
>+	 * @DRIVER_GEM_GPUVA:
>+	 *
>+	 * Driver supports user defined GPU VA bindings for GEM objects.
>+	 */
>+	DRIVER_GEM_GPUVA		= BIT(8),
>
> 	/* IMPORTANT: Below are all the legacy flags, add new ones above. */
>
>diff --git a/include/drm/drm_gem.h b/include/drm/drm_gem.h
>index 772a4adf5287..4a3679034966 100644
>--- a/include/drm/drm_gem.h
>+++ b/include/drm/drm_gem.h
>@@ -36,6 +36,8 @@
>
> #include <linux/kref.h>
> #include <linux/dma-resv.h>
>+#include <linux/list.h>
>+#include <linux/mutex.h>
>
> #include <drm/drm_vma_manager.h>
>
>@@ -337,6 +339,17 @@ struct drm_gem_object {
> 	 */
> 	struct dma_resv _resv;
>
>+	/**
>+	 * @gpuva:
>+	 *
>+	 * Provides the list and list mutex of GPU VAs attached to this
>+	 * GEM object.
>+	 */
>+	struct {
>+		struct list_head list;
>+		struct mutex mutex;
>+	} gpuva;
>+
> 	/**
> 	 * @funcs:
> 	 *
>@@ -479,4 +492,66 @@ void drm_gem_lru_move_tail(struct drm_gem_lru *lru, struct drm_gem_object *obj);
> unsigned long drm_gem_lru_scan(struct drm_gem_lru *lru, unsigned nr_to_scan,
> 			       bool (*shrink)(struct drm_gem_object *obj));
>
>+/**
>+ * drm_gem_gpuva_init - initialize the gpuva list of a GEM object
>+ * @obj: the &drm_gem_object
>+ *
>+ * This initializes the &drm_gem_object's &drm_gpuva list and the mutex
>+ * protecting it.
>+ *
>+ * Calling this function is only necessary for drivers intending to support the
>+ * &drm_driver_feature DRIVER_GEM_GPUVA.
>+ */
>+static inline void drm_gem_gpuva_init(struct drm_gem_object *obj)
>+{
>+	INIT_LIST_HEAD(&obj->gpuva.list);
>+	mutex_init(&obj->gpuva.mutex);
>+}
>+
>+/**
>+ * drm_gem_gpuva_lock - lock the GEM's gpuva list mutex
>+ * @obj: the &drm_gem_object
>+ *
>+ * This unlocks the mutex protecting the &drm_gem_object's &drm_gpuva list.
>+ */
>+static inline void drm_gem_gpuva_lock(struct drm_gem_object *obj)
>+{
>+	mutex_lock(&obj->gpuva.mutex);
>+}
>+
>+/**
>+ * drm_gem_gpuva_unlock - unlock the GEM's gpuva list mutex
>+ * @obj: the &drm_gem_object
>+ *
>+ * This unlocks the mutex protecting the &drm_gem_object's &drm_gpuva list.
>+ */
>+static inline void drm_gem_gpuva_unlock(struct drm_gem_object *obj)
>+{
>+	mutex_unlock(&obj->gpuva.mutex);
>+}
>+
>+/**
>+ * drm_gem_for_each_gpuva - iternator to walk over a list of gpuvas
>+ * @entry: &drm_gpuva structure to assign to in each iteration step
>+ * @obj: the &drm_gem_object the &drm_gpuvas to walk are associated with
>+ *
>+ * This iterator walks over all &drm_gpuva structures associated with the
>+ * &drm_gpuva_manager.
>+ */
>+#define drm_gem_for_each_gpuva(entry, obj) \
>+	list_for_each_entry(entry, &obj->gpuva.list, head)
>+
>+/**
>+ * drm_gem_for_each_gpuva_safe - iternator to safely walk over a list of gpuvas
>+ * @entry: &drm_gpuva structure to assign to in each iteration step
>+ * @next: &next &drm_gpuva to store the next step
>+ * @obj: the &drm_gem_object the &drm_gpuvas to walk are associated with
>+ *
>+ * This iterator walks over all &drm_gpuva structures associated with the
>+ * &drm_gem_object. It is implemented with list_for_each_entry_safe(), hence
>+ * it is save against removal of elements.
>+ */
>+#define drm_gem_for_each_gpuva_safe(entry, next, obj) \
>+	list_for_each_entry_safe(entry, next, &obj->gpuva.list, head)
>+
> #endif /* __DRM_GEM_H__ */
>diff --git a/include/drm/drm_gpuva_mgr.h b/include/drm/drm_gpuva_mgr.h
>new file mode 100644
>index 000000000000..adeb0c916e91
>--- /dev/null
>+++ b/include/drm/drm_gpuva_mgr.h
>@@ -0,0 +1,527 @@
>+// SPDX-License-Identifier: GPL-2.0
>+
>+#ifndef __DRM_GPUVA_MGR_H__
>+#define __DRM_GPUVA_MGR_H__
>+
>+/*
>+ * 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.
>+ */
>+
>+#include <drm/drm_mm.h>
>+#include <linux/mm.h>
>+#include <linux/rbtree.h>
>+#include <linux/spinlock.h>
>+#include <linux/types.h>
>+
>+struct drm_gpuva_region;
>+struct drm_gpuva;
>+struct drm_gpuva_ops;
>+
>+/**
>+ * struct drm_gpuva_manager - DRM GPU VA Manager
>+ *
>+ * The DRM GPU VA Manager keeps track of a GPU's virtual address space by using
>+ * the &drm_mm range allocator. Typically, this structure is embedded in bigger
>+ * driver structures.
>+ *
>+ * Drivers can pass addresses and ranges in an arbitrary unit, e.g. bytes or
>+ * pages.
>+ *
>+ * There should be one manager instance per GPU virtual address space.
>+ */
>+struct drm_gpuva_manager {
>+	/**
>+	 * @name: the name of the DRM GPU VA space
>+	 */
>+	const char *name;
>+
>+	/**
>+	 * @mm_start: start of the VA space
>+	 */
>+	u64 mm_start;
>+
>+	/**
>+	 * @mm_range: length of the VA space
>+	 */
>+	u64 mm_range;
>+
>+	/**
>+	 * @region_mm: the &drm_mm range allocator to track GPU VA regions
>+	 */
>+	struct drm_mm region_mm;
>+
>+	/**
>+	 * @va_mm: the &drm_mm range allocator to track GPU VA mappings
>+	 */
>+	struct drm_mm va_mm;
>+
>+	/**
>+	 * @kernel_alloc_node:
>+	 *
>+	 * &drm_mm_node representing the address space cutout reserved for
>+	 * the kernel
>+	 */
>+	struct drm_mm_node kernel_alloc_node;
>+};
>+
>+void drm_gpuva_manager_init(struct drm_gpuva_manager *mgr,
>+			    const char *name,
>+			    u64 start_offset, u64 range,
>+			    u64 reserve_offset, u64 reserve_range);
>+void drm_gpuva_manager_destroy(struct drm_gpuva_manager *mgr);
>+
>+/**
>+ * struct drm_gpuva_region - structure to track a portion of GPU VA space
>+ *
>+ * This structure represents a portion of a GPUs VA space and is associated
>+ * with a &drm_gpuva_manager. Internally it is based on a &drm_mm_node.
>+ *
>+ * GPU VA mappings, represented by &drm_gpuva objects, are restricted to be
>+ * placed within a &drm_gpuva_region.
>+ */
>+struct drm_gpuva_region {
>+	/**
>+	 * @node: the &drm_mm_node to track the GPU VA region
>+	 */
>+	struct drm_mm_node node;
>+
>+	/**
>+	 * @mgr: the &drm_gpuva_manager this object is associated with
>+	 */
>+	struct drm_gpuva_manager *mgr;
>+
>+	/**
>+	 * @sparse: indicates whether this region is sparse
>+	 */
>+	bool sparse;
>+};
>+
>+struct drm_gpuva_region *
>+drm_gpuva_region_find(struct drm_gpuva_manager *mgr,
>+		      u64 addr, u64 range);
>+int drm_gpuva_region_insert(struct drm_gpuva_manager *mgr,
>+			    struct drm_gpuva_region *reg,
>+			    u64 addr, u64 range);
>+void drm_gpuva_region_destroy(struct drm_gpuva_manager *mgr,
>+			      struct drm_gpuva_region *reg);
>+
>+int drm_gpuva_insert(struct drm_gpuva_manager *mgr,
>+		     struct drm_gpuva *va,
>+		     u64 addr, u64 range);
>+/**
>+ * drm_gpuva_for_each_region_in_range - iternator to walk over a range of nodes
>+ * @node__: &drm_gpuva_region structure to assign to in each iteration step
>+ * @gpuva__: &drm_gpuva_manager structure to walk
>+ * @start__: starting offset, the first node will overlap this
>+ * @end__: ending offset, the last node will start before this (but may overlap)
>+ *
>+ * This iterator walks over all nodes in the range allocator that lie
>+ * between @start and @end. It is implemented similarly to list_for_each(),
>+ * but is using &drm_mm's internal interval tree to accelerate the search for
>+ * the starting node, and hence isn't safe against removal of elements. It
>+ * assumes that @end is within (or is the upper limit of) the &drm_gpuva_manager.
>+ * If [@start, @end] are beyond the range of the &drm_gpuva_manager, the
>+ * iterator may walk over the special _unallocated_ &drm_mm.head_node of the
>+ * backing &drm_mm, and may even continue indefinitely.
>+ */
>+#define drm_gpuva_for_each_region_in_range(node__, gpuva__, start__, end__) \
>+	for (node__ = (struct drm_gpuva_region *)__drm_mm_interval_first(&(gpuva__)->region_mm, \
>+									 (start__), (end__)-1); \
>+	     node__->node.start < (end__); \
>+	     node__ = (struct drm_gpuva_region *)list_next_entry(&node__->node, node_list))
>+
>+/**
>+ * drm_gpuva_for_each_region - iternator to walk over a range of nodes
>+ * @entry: &drm_gpuva_region structure to assign to in each iteration step
>+ * @gpuva: &drm_gpuva_manager structure to walk
>+ *
>+ * This iterator walks over all &drm_gpuva_region structures associated with the
>+ * &drm_gpuva_manager.
>+ */
>+#define drm_gpuva_for_each_region(entry, gpuva) \
>+	list_for_each_entry(entry, drm_mm_nodes(&(gpuva)->region_mm), node.node_list)
>+
>+/**
>+ * drm_gpuva_for_each_region_safe - iternator to safely walk over a range of
>+ * nodes
>+ * @entry: &drm_gpuva_region structure to assign to in each iteration step
>+ * @next: &next &drm_gpuva_region to store the next step
>+ * @gpuva: &drm_gpuva_manager structure to walk
>+ *
>+ * This iterator walks over all &drm_gpuva_region structures associated with the
>+ * &drm_gpuva_manager. It is implemented with list_for_each_safe(), so save
>+ * against removal of elements.
>+ */
>+#define drm_gpuva_for_each_region_safe(entry, next, gpuva) \
>+	list_for_each_entry_safe(entry, next, drm_mm_nodes(&(gpuva)->region_mm), node.node_list)
>+
>+
>+/**
>+ * enum drm_gpuva_flags - flags for struct drm_gpuva
>+ */
>+enum drm_gpuva_flags {
>+	/**
>+	 * @DRM_GPUVA_SWAPPED: flag indicating that the &drm_gpuva is swapped
>+	 */
>+	DRM_GPUVA_SWAPPED = (1 << 0),
>+};
>+
>+/**
>+ * struct drm_gpuva - structure to track a GPU VA mapping
>+ *
>+ * This structure represents a GPU VA mapping and is associated with a
>+ * &drm_gpuva_manager. Internally it is based on a &drm_mm_node.
>+ *
>+ * Typically, this structure is embedded in bigger driver structures.
>+ */
>+struct drm_gpuva {
>+	/**
>+	 * @node: the &drm_mm_node to track the GPU VA mapping
>+	 */
>+	struct drm_mm_node node;
>+
>+	/**
>+	 * @mgr: the &drm_gpuva_manager this object is associated with
>+	 */
>+	struct drm_gpuva_manager *mgr;
>+
>+	/**
>+	 * @region: the &drm_gpuva_region the &drm_gpuva is mapped in
>+	 */
>+	struct drm_gpuva_region *region;
>+
>+	/**
>+	 * @head: the &list_head to attach this object to a &drm_gem_object
>+	 */
>+	struct list_head head;
>+
>+	/**
>+	 * @flags: the &drm_gpuva_flags for this mapping
>+	 */
>+	enum drm_gpuva_flags flags;
>+
>+	/**
>+	 * @gem: structure containing the &drm_gem_object and it's offset
>+	 */
>+	struct {
>+		/**
>+		 * @offset: the offset within the &drm_gem_object
>+		 */
>+		u64 offset;
>+
>+		/**
>+		 * @obj: the mapped &drm_gem_object
>+		 */
>+		struct drm_gem_object *obj;
>+	} gem;
>+};
>+
>+void drm_gpuva_link_locked(struct drm_gpuva *va);
>+void drm_gpuva_link_unlocked(struct drm_gpuva *va);
>+void drm_gpuva_unlink_locked(struct drm_gpuva *va);
>+void drm_gpuva_unlink_unlocked(struct drm_gpuva *va);
>+
>+void drm_gpuva_destroy_locked(struct drm_gpuva *va);
>+void drm_gpuva_destroy_unlocked(struct drm_gpuva *va);
>+
>+struct drm_gpuva *drm_gpuva_find(struct drm_gpuva_manager *mgr,
>+				 u64 addr, u64 range);
>+struct drm_gpuva *drm_gpuva_find_prev(struct drm_gpuva_manager *mgr, u64 start);
>+struct drm_gpuva *drm_gpuva_find_next(struct drm_gpuva_manager *mgr, u64 end);
>+
>+/**
>+ * drm_gpuva_swap - sets whether the backing BO of this &drm_gpuva is swapped
>+ * @va: the &drm_gpuva to set the swap flag of
>+ * @swap: indicates whether the &drm_gpuva is swapped
>+ */
>+static inline void drm_gpuva_swap(struct drm_gpuva *va, bool swap)
>+{
>+	if (swap)
>+		va->flags |= DRM_GPUVA_SWAPPED;
>+	else
>+		va->flags &= ~DRM_GPUVA_SWAPPED;
>+}
>+
>+/**
>+ * drm_gpuva_swapped - indicates whether the backing BO of this &drm_gpuva
>+ * is swapped
>+ * @va: the &drm_gpuva to check
>+ */
>+static inline bool drm_gpuva_swapped(struct drm_gpuva *va)
>+{
>+	return va->flags & DRM_GPUVA_SWAPPED;
>+}
>+
>+/**
>+ * drm_gpuva_for_each_va_in_range - iternator to walk over a range of nodes
>+ * @node__: &drm_gpuva structure to assign to in each iteration step
>+ * @gpuva__: &drm_gpuva_manager structure to walk
>+ * @start__: starting offset, the first node will overlap this
>+ * @end__: ending offset, the last node will start before this (but may overlap)
>+ *
>+ * This iterator walks over all nodes in the range allocator that lie
>+ * between @start and @end. It is implemented similarly to list_for_each(),
>+ * but is using &drm_mm's internal interval tree to accelerate the search for
>+ * the starting node, and hence isn't safe against removal of elements. It
>+ * assumes that @end is within (or is the upper limit of) the &drm_gpuva_manager.
>+ * If [@start, @end] are beyond the range of the &drm_gpuva_manager, the
>+ * iterator may walk over the special _unallocated_ &drm_mm.head_node of the
>+ * backing &drm_mm, and may even continue indefinitely.
>+ */
>+#define drm_gpuva_for_each_va_in_range(node__, gpuva__, start__, end__) \
>+	for (node__ = (struct drm_gpuva *)__drm_mm_interval_first(&(gpuva__)->va_mm, \
>+								  (start__), (end__)-1); \
>+	     node__->node.start < (end__); \
>+	     node__ = (struct drm_gpuva *)list_next_entry(&node__->node, node_list))
>+
>+/**
>+ * drm_gpuva_for_each_va - iternator to walk over a range of nodes
>+ * @entry: &drm_gpuva structure to assign to in each iteration step
>+ * @gpuva: &drm_gpuva_manager structure to walk
>+ *
>+ * This iterator walks over all &drm_gpuva structures associated with the
>+ * &drm_gpuva_manager.
>+ */
>+#define drm_gpuva_for_each_va(entry, gpuva) \
>+	list_for_each_entry(entry, drm_mm_nodes(&(gpuva)->va_mm), node.node_list)
>+
>+/**
>+ * drm_gpuva_for_each_va_safe - iternator to safely walk over a range of
>+ * nodes
>+ * @entry: &drm_gpuva structure to assign to in each iteration step
>+ * @next: &next &drm_gpuva to store the next step
>+ * @gpuva: &drm_gpuva_manager structure to walk
>+ *
>+ * This iterator walks over all &drm_gpuva structures associated with the
>+ * &drm_gpuva_manager. It is implemented with list_for_each_safe(), so save
>+ * against removal of elements.
>+ */
>+#define drm_gpuva_for_each_va_safe(entry, next, gpuva) \
>+	list_for_each_entry_safe(entry, next, drm_mm_nodes(&(gpuva)->va_mm), node.node_list)
>+
>+/**
>+ * enum drm_gpuva_op_type - GPU VA operation type
>+ *
>+ * Operations to alter the GPU VA mappings tracked by the &drm_gpuva_manager
>+ * can be map, remap or unmap operations.
>+ */
>+enum drm_gpuva_op_type {
>+	/**
>+	 * @DRM_GPUVA_OP_MAP: the map op type
>+	 */
>+	DRM_GPUVA_OP_MAP,
>+
>+	/**
>+	 * @DRM_GPUVA_OP_REMAP: the remap op type
>+	 */
>+	DRM_GPUVA_OP_REMAP,
>+
>+	/**
>+	 * @DRM_GPUVA_OP_UNMAP: the unmap op type
>+	 */
>+	DRM_GPUVA_OP_UNMAP,
>+};
>+
>+/**
>+ * struct drm_gpuva_op_map - GPU VA map operation
>+ *
>+ * This structure represents a single map operation generated by the
>+ * DRM GPU VA manager.
>+ */
>+struct drm_gpuva_op_map {
>+	/**
>+	 * @va: structure containing address and range of a map
>+	 * operation
>+	 */
>+	struct {
>+		/**
>+		 * @addr: the base address of the new mapping
>+		 */
>+		u64 addr;
>+
>+		/**
>+		 * @range: the range of the new mapping
>+		 */
>+		u64 range;
>+	} va;
>+
>+	/**
>+	 * @gem: structure containing the &drm_gem_object and it's offset
>+	 */
>+	struct {
>+		/**
>+		 * @offset: the offset within the &drm_gem_object
>+		 */
>+		u64 offset;
>+
>+		/**
>+		 * @obj: the &drm_gem_object to map
>+		 */
>+		struct drm_gem_object *obj;
>+	} gem;
>+};
>+
>+/**
>+ * struct drm_gpuva_op_unmap - GPU VA unmap operation
>+ *
>+ * This structure represents a single unmap operation generated by the
>+ * DRM GPU VA manager.
>+ */
>+struct drm_gpuva_op_unmap {
>+	/**
>+	 * @va: the &drm_gpuva to unmap
>+	 */
>+	struct drm_gpuva *va;
>+
>+	/**
>+	 * @keep:
>+	 *
>+	 * Indicates whether this &drm_gpuva is physically contiguous with the
>+	 * original mapping request.
>+	 *
>+	 * Optionally, if &keep is set, drivers may keep the actual page table
>+	 * mappings for this &drm_gpuva, adding the missing page table entries
>+	 * only and update the &drm_gpuva_manager accordingly.
>+	 */
>+	bool keep;
>+};
>+
>+/**
>+ * struct drm_gpuva_op_remap - GPU VA remap operation
>+ *
>+ * This represents a single remap operation generated by the DRM GPU VA manager.
>+ *
>+ * A remap operation is generated when an existing GPU VA mmapping is split up
>+ * by inserting a new GPU VA mapping or by partially unmapping existent
>+ * mapping(s), hence it consists of a maximum of two map and one unmap
>+ * operation.
>+ *
>+ * The @unmap operation takes care of removing the original existing mapping.
>+ * @prev is used to remap the preceding part, @next the subsequent part.
>+ *
>+ * If either a new mapping's start address is aligned with the start address
>+ * of the old mapping or the new mapping's end address is aligned with the
>+ * end address of the old mapping, either @prev or @next is NULL.
>+ *
>+ * Note, the reason for a dedicated remap operation, rather than arbitrary
>+ * unmap and map operations, is to give drivers the chance of extracting driver
>+ * specific data for creating the new mappings from the unmap operations's
>+ * &drm_gpuva structure which typically is embedded in larger driver specific
>+ * structures.
>+ */
>+struct drm_gpuva_op_remap {
>+	/**
>+	 * @prev: the preceding part of a split mapping
>+	 */
>+	struct drm_gpuva_op_map *prev;
>+
>+	/**
>+	 * @next: the subsequent part of a split mapping
>+	 */
>+	struct drm_gpuva_op_map *next;
>+
>+	/**
>+	 * @unmap: the unmap operation for the original existing mapping
>+	 */
>+	struct drm_gpuva_op_unmap *unmap;
>+};
>+
>+/**
>+ * struct drm_gpuva_op - GPU VA operation
>+ *
>+ * This structure represents a single generic operation, which can be either
>+ * map, unmap or remap.
>+ *
>+ * The particular type of the operation is defined by @op.
>+ */
>+struct drm_gpuva_op {
>+	/**
>+	 * @entry:
>+	 *
>+	 * The &list_head used to distribute instances of this struct within
>+	 * &drm_gpuva_ops.
>+	 */
>+	struct list_head entry;
>+
>+	/**
>+	 * @op: the type of the operation
>+	 */
>+	enum drm_gpuva_op_type op;
>+
>+	union {
>+		/**
>+		 * @map: the map operation
>+		 */
>+		struct drm_gpuva_op_map map;
>+
>+		/**
>+		 * @unmap: the unmap operation
>+		 */
>+		struct drm_gpuva_op_unmap unmap;
>+
>+		/**
>+		 * @remap: the remap operation
>+		 */
>+		struct drm_gpuva_op_remap remap;
>+	};
>+};
>+
>+/**
>+ * struct drm_gpuva_ops - wraps a list of &drm_gpuva_op
>+ */
>+struct drm_gpuva_ops {
>+	/**
>+	 * @list: the &list_head
>+	 */
>+	struct list_head list;
>+};
>+
>+/**
>+ * drm_gpuva_for_each_op - iterator to walk over all ops
>+ * @op: &drm_gpuva_op to assign in each iteration step
>+ * @ops: &drm_gpuva_ops to walk
>+ *
>+ * This iterator walks over all ops within a given list of operations.
>+ */
>+#define drm_gpuva_for_each_op(op, ops) list_for_each_entry(op, &(ops)->list, entry)
>+
>+/**
>+ * drm_gpuva_for_each_op_safe - iterator to safely walk over all ops
>+ * @op: &drm_gpuva_op to assign in each iteration step
>+ * @next: &next &drm_gpuva_op to store the next step
>+ * @ops: &drm_gpuva_ops to walk
>+ *
>+ * This iterator walks over all ops within a given list of operations. It is
>+ * implemented with list_for_each_safe(), so save against removal of elements.
>+ */
>+#define drm_gpuva_for_each_op_safe(op, next, ops) \
>+	list_for_each_entry_safe(op, next, &(ops)->list, entry)
>+
>+struct drm_gpuva_ops *
>+drm_gpuva_sm_map_ops_create(struct drm_gpuva_manager *mgr,
>+			    u64 addr, u64 range,
>+			    struct drm_gem_object *obj, u64 offset);
>+struct drm_gpuva_ops *
>+drm_gpuva_sm_unmap_ops_create(struct drm_gpuva_manager *mgr,
>+			      u64 addr, u64 range);
>+void drm_gpuva_ops_free(struct drm_gpuva_ops *ops);
>+
>+#endif /* __DRM_GPUVA_MGR_H__ */
>-- 
>2.39.0
>

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