Re: [PATCH drm-next v2 05/16] drm: manager to keep track of GPUs VA mappings

[Christian König]

Am 17.02.23 um 14:44 schrieb Danilo Krummrich:
> Add infrastructure to keep track of GPU virtual address (VA) mappings
> with a decicated VA space manager implementation.
>
> 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 infrastructure to track GPU VA allocations and mappings,
>     making use of the maple_tree.
>
> 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.
>
> Suggested-by: Dave Airlie <airlied@xxxxxxxxxx>
> Signed-off-by: Danilo Krummrich <dakr@xxxxxxxxxx>
> ---
>   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 | 1704 +++++++++++++++++++++++++++++++
>   include/drm/drm_drv.h           |    6 +
>   include/drm/drm_gem.h           |   75 ++
>   include/drm/drm_gpuva_mgr.h     |  714 +++++++++++++
>   7 files changed, 2534 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 d40defbb0347..4d098efffb98 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..19f583704562
> --- /dev/null
> +++ b/drivers/gpu/drm/drm_gpuva_mgr.c
> @@ -0,0 +1,1704 @@
> +// 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@xxxxxxxxxx>
> + *
> + */
> +
> +#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.
> + *
> + * If the &DRM_GPUVA_MANAGER_REGIONS feature is enabled, 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'.

Well since we have now found that there is absolutely no technical 
reason for having those regions could we please drop them?

I don't really see a need for them any more.

Regards,
Christian.

> + *
> + * The GPU VA manager internally uses &maple_tree structures 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.
> + *
> + * Drivers can call drm_gpuva_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_gpuva_fn_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, 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 passed to drm_gpuva_sm_map().
> + *
> + * &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.
> + *
> + * To update the &drm_gpuva_manager's view of the GPU VA space
> + * drm_gpuva_insert() and drm_gpuva_remove() should be used.
> + *
> + * Analogous to drm_gpuva_sm_map() drm_gpuva_sm_unmap() uses &drm_gpuva_fn_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.
> + *
> + * The following diagram depicts the basic relationships of existent GPU VA
> + * mappings, a newly requested mapping and the resulting mappings as implemented
> + * by drm_gpuva_sm_map() - it doesn't cover any arbitrary combinations of these.
> + *
> + * 1) Requested mapping is identical, hence noop.
> + *
> + *    ::
> + *
> + *	     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 it's 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, hence noop.
> + *
> + *    ::
> + *
> + *	     0     a     2
> + *	old: |-----------| (bo_offset=n)
> + *
> + *	     0  a  1
> + *	req: |-----|       (bo_offset=n)
> + *
> + *	     0     a     2
> + *	new: |-----------| (bo_offset=n)
> + *
> + *
> + * 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, hence noop.
> + *
> + *    ::
> + *
> + *	      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 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. Hence, merge both mappings.
> + *
> + *     ::
> + *
> + *	      0     a     2
> + *	 old: |-----------|       (bo_offset=n)
> + *
> + *	            1     a     3
> + *	 req:       |-----------| (bo_offset=n+1)
> + *
> + *	      0        a        3
> + *	 new: |-----------------| (bo_offset=n)
> + *
> + *
> + * 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, hence noop.
> + *
> + *     ::
> + *
> + *	      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 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 it's 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)
> + *
> + *
> + * 16) Requested mapping fills the gap between two existent mappings all having
> + *     the same backing BO, such that all three have a contiguous BO offset.
> + *     Hence, merge all mappings.
> + *
> + *     ::
> + *
> + *	      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, removing and iterating
> + * &drm_gpuva and &drm_gpuva_region 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.
> + */
> +
> +
> +static int __drm_gpuva_region_insert(struct drm_gpuva_manager *mgr,
> +				     struct drm_gpuva_region *reg);
> +static void __drm_gpuva_region_remove(struct drm_gpuva_region *reg);
> +
> +/**
> + * 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
> + * @ops: &drm_gpuva_fn_ops called on &drm_gpuva_sm_map / &drm_gpuva_sm_unmap
> + * @flags: the feature flags of the &drm_gpuva_manager
> + *
> + * 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,
> +		       struct drm_gpuva_fn_ops *ops,
> +		       enum drm_gpuva_mgr_flags flags)
> +{
> +	mt_init_flags(&mgr->region_mt, MT_FLAGS_LOCK_NONE);
> +	mt_init_flags(&mgr->va_mt, MT_FLAGS_LOCK_NONE);
> +
> +	mgr->mm_start = start_offset;
> +	mgr->mm_range = range;
> +
> +	mgr->name = name ? name : "unknown";
> +	mgr->ops = ops;
> +	mgr->flags = flags;
> +
> +	memset(&mgr->kernel_alloc_region, 0, sizeof(struct drm_gpuva_region));
> +	mgr->kernel_alloc_region.va.addr = reserve_offset;
> +	mgr->kernel_alloc_region.va.range = reserve_range;
> +
> +	__drm_gpuva_region_insert(mgr, &mgr->kernel_alloc_region);
> +}
> +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_gpuva_region_remove(&mgr->kernel_alloc_region);
> +
> +	WARN(!mtree_empty(&mgr->va_mt),
> +	     "GPUVA tree is not empty, potentially leaking memory.");
> +	__mt_destroy(&mgr->va_mt);
> +
> +	WARN(!mtree_empty(&mgr->region_mt),
> +	     "GPUVA region tree is not empty, potentially leaking memory.");
> +	__mt_destroy(&mgr->region_mt);
> +}
> +EXPORT_SYMBOL(drm_gpuva_manager_destroy);
> +
> +static inline bool
> +drm_gpuva_in_mm_range(struct drm_gpuva_manager *mgr, u64 addr, u64 range)
> +{
> +	u64 end = addr + range;
> +	u64 mm_start = mgr->mm_start;
> +	u64 mm_end = mm_start + mgr->mm_range;
> +
> +	return addr < mm_end && mm_start < end;
> +}
> +
> +static inline bool
> +drm_gpuva_in_kernel_region(struct drm_gpuva_manager *mgr, u64 addr, u64 range)
> +{
> +	u64 end = addr + range;
> +	u64 kstart = mgr->kernel_alloc_region.va.addr;
> +	u64 kend = kstart + mgr->kernel_alloc_region.va.range;
> +
> +	return addr < kend && kstart < end;
> +}
> +
> +static struct drm_gpuva_region *
> +drm_gpuva_in_region(struct drm_gpuva_manager *mgr, u64 addr, u64 range)
> +{
> +	DRM_GPUVA_REGION_ITER(it, mgr);
> +
> +	/* Find the VA region the requested range is strictly enclosed by. */
> +	drm_gpuva_iter_for_each_range(it, addr, addr + range) {
> +		struct drm_gpuva_region *reg = it.reg;
> +
> +		if (reg->va.addr <= addr &&
> +		    reg->va.addr + reg->va.range >= addr + range &&
> +		    reg != &mgr->kernel_alloc_region)
> +			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_remove_iter - removes the iterators current element
> + * @it: the &drm_gpuva_iterator
> + *
> + * This removes the element the iterator currently points to.
> + */
> +void
> +drm_gpuva_iter_remove(struct drm_gpuva_iterator *it)
> +{
> +	mas_erase(&it->mas);
> +}
> +EXPORT_SYMBOL(drm_gpuva_iter_remove);
> +
> +/**
> + * 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.
> + *
> + * Returns: 0 on success, negative error code on failure.
> + */
> +int
> +drm_gpuva_insert(struct drm_gpuva_manager *mgr,
> +		 struct drm_gpuva *va)
> +{
> +	u64 addr = va->va.addr;
> +	u64 range = va->va.range;
> +	MA_STATE(mas, &mgr->va_mt, addr, addr + range - 1);
> +	struct drm_gpuva_region *reg = NULL;
> +	int ret;
> +
> +	if (unlikely(!drm_gpuva_in_mm_range(mgr, addr, range)))
> +		return -EINVAL;
> +
> +	if (unlikely(drm_gpuva_in_kernel_region(mgr, addr, range)))
> +		return -EINVAL;
> +
> +	if (mgr->flags & DRM_GPUVA_MANAGER_REGIONS) {
> +		reg = drm_gpuva_in_region(mgr, addr, range);
> +		if (unlikely(!reg))
> +			return -EINVAL;
> +	}
> +
> +	if (unlikely(drm_gpuva_find_first(mgr, addr, range)))
> +		return -EEXIST;
> +
> +	ret = mas_store_gfp(&mas, va, GFP_KERNEL);
> +	if (unlikely(ret))
> +		return ret;
> +
> +	va->mgr = mgr;
> +	va->region = reg;
> +
> +	return 0;
> +}
> +EXPORT_SYMBOL(drm_gpuva_insert);
> +
> +/**
> + * drm_gpuva_remove - remove a &drm_gpuva
> + * @va: the &drm_gpuva to remove
> + *
> + * This removes the given &va from the underlaying tree.
> + */
> +void
> +drm_gpuva_remove(struct drm_gpuva *va)
> +{
> +	MA_STATE(mas, &va->mgr->va_mt, va->va.addr, 0);
> +
> +	mas_erase(&mas);
> +}
> +EXPORT_SYMBOL(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.
> + */
> +void
> +drm_gpuva_link(struct drm_gpuva *va)
> +{
> +	if (likely(va->gem.obj))
> +		list_add_tail(&va->head, &va->gem.obj->gpuva.list);
> +}
> +EXPORT_SYMBOL(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.
> + */
> +void
> +drm_gpuva_unlink(struct drm_gpuva *va)
> +{
> +	if (likely(va->gem.obj))
> +		list_del_init(&va->head);
> +}
> +EXPORT_SYMBOL(drm_gpuva_unlink);
> +
> +/**
> + * drm_gpuva_find_first - find the first &drm_gpuva in the given range
> + * @mgr: the &drm_gpuva_manager 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_gpuva_manager *mgr,
> +		     u64 addr, u64 range)
> +{
> +	MA_STATE(mas, &mgr->va_mt, addr, 0);
> +
> +	return mas_find(&mas, addr + range - 1);
> +}
> +EXPORT_SYMBOL(drm_gpuva_find_first);
> +
> +/**
> + * 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;
> +
> +	va = drm_gpuva_find_first(mgr, addr, range);
> +	if (!va)
> +		goto out;
> +
> +	if (va->va.range != range)
> +		goto out;
> +
> +	return va;
> +
> +out:
> +	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)
> +{
> +	MA_STATE(mas, &mgr->va_mt, start, 0);
> +
> +	if (start <= mgr->mm_start ||
> +	    start > (mgr->mm_start + mgr->mm_range))
> +		return NULL;
> +
> +	return mas_prev(&mas, start - 1);
> +}
> +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)
> +{
> +	MA_STATE(mas, &mgr->va_mt, end - 1, 0);
> +
> +	if (end < mgr->mm_start ||
> +	    end >= (mgr->mm_start + mgr->mm_range))
> +		return NULL;
> +
> +	return mas_next(&mas, end);
> +}
> +EXPORT_SYMBOL(drm_gpuva_find_next);
> +
> +static int
> +__drm_gpuva_region_insert(struct drm_gpuva_manager *mgr,
> +			  struct drm_gpuva_region *reg)
> +{
> +	u64 addr = reg->va.addr;
> +	u64 range = reg->va.range;
> +	MA_STATE(mas, &mgr->region_mt, addr, addr + range - 1);
> +	int ret;
> +
> +	if (unlikely(!drm_gpuva_in_mm_range(mgr, addr, range)))
> +		return -EINVAL;
> +
> +	ret = mas_store_gfp(&mas, reg, GFP_KERNEL);
> +	if (unlikely(ret))
> +		return ret;
> +
> +	reg->mgr = mgr;
> +
> +	return 0;
> +}
> +
> +/**
> + * 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)
> +{
> +	if (unlikely(!(mgr->flags & DRM_GPUVA_MANAGER_REGIONS)))
> +		return -EINVAL;
> +
> +	return __drm_gpuva_region_insert(mgr, reg);
> +}
> +EXPORT_SYMBOL(drm_gpuva_region_insert);
> +
> +static void
> +__drm_gpuva_region_remove(struct drm_gpuva_region *reg)
> +{
> +	struct drm_gpuva_manager *mgr = reg->mgr;
> +	MA_STATE(mas, &mgr->region_mt, reg->va.addr, 0);
> +
> +	mas_erase(&mas);
> +}
> +
> +/**
> + * drm_gpuva_region_remove - remove a &drm_gpuva_region
> + * @reg: the &drm_gpuva to remove
> + *
> + * This removes the given &reg from the underlaying tree.
> + */
> +void
> +drm_gpuva_region_remove(struct drm_gpuva_region *reg)
> +{
> +	struct drm_gpuva_manager *mgr = reg->mgr;
> +
> +	if (unlikely(!(mgr->flags & DRM_GPUVA_MANAGER_REGIONS)))
> +		return;
> +
> +	if (unlikely(reg == &mgr->kernel_alloc_region)) {
> +		WARN(1, "Can't destroy kernel reserved region.\n");
> +		return;
> +	}
> +
> +	if (unlikely(!drm_gpuva_region_empty(reg)))
> +		WARN(1, "GPU VA region should be empty on destroy.\n");
> +
> +	__drm_gpuva_region_remove(reg);
> +}
> +EXPORT_SYMBOL(drm_gpuva_region_remove);
> +
> +/**
> + * drm_gpuva_region_empty - indicate whether a &drm_gpuva_region is empty
> + * @reg: the &drm_gpuva to destroy
> + *
> + * Returns: true if the &drm_gpuva_region is empty, false otherwise
> + */
> +bool
> +drm_gpuva_region_empty(struct drm_gpuva_region *reg)
> +{
> +	DRM_GPUVA_ITER(it, reg->mgr);
> +
> +	drm_gpuva_iter_for_each_range(it, reg->va.addr,
> +				      reg->va.addr +
> +				      reg->va.range)
> +		return false;
> +
> +	return true;
> +}
> +EXPORT_SYMBOL(drm_gpuva_region_empty);
> +
> +/**
> + * drm_gpuva_region_find_first - find the first &drm_gpuva_region in the given
> + * range
> + * @mgr: the &drm_gpuva_manager to search in
> + * @addr: the &drm_gpuva_regions address
> + * @range: the &drm_gpuva_regions range
> + *
> + * Returns: the first &drm_gpuva_region within the given range
> + */
> +struct drm_gpuva_region *
> +drm_gpuva_region_find_first(struct drm_gpuva_manager *mgr,
> +			    u64 addr, u64 range)
> +{
> +	MA_STATE(mas, &mgr->region_mt, addr, 0);
> +
> +	return mas_find(&mas, addr + range - 1);
> +}
> +EXPORT_SYMBOL(drm_gpuva_region_find_first);
> +
> +/**
> + * 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;
> +
> +	reg = drm_gpuva_region_find_first(mgr, addr, range);
> +	if (!reg)
> +		goto out;
> +
> +	if (reg->va.range != range)
> +		goto out;
> +
> +	return reg;
> +
> +out:
> +	return NULL;
> +}
> +EXPORT_SYMBOL(drm_gpuva_region_find);
> +
> +static int
> +op_map_cb(int (*step)(struct drm_gpuva_op *, void *),
> +	  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 step(&op, priv);
> +}
> +
> +static int
> +op_remap_cb(int (*step)(struct drm_gpuva_op *, void *),
> +	    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 step(&op, priv);
> +}
> +
> +static int
> +op_unmap_cb(int (*step)(struct drm_gpuva_op *, void *),
> +	    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 step(&op, priv);
> +}
> +
> +static inline bool
> +gpuva_should_merge(struct drm_gpuva *va)
> +{
> +	/* Never merge mappings with NULL GEMs. */
> +	return !!va->gem.obj;
> +}
> +
> +static int
> +__drm_gpuva_sm_map(struct drm_gpuva_manager *mgr,
> +		   struct drm_gpuva_fn_ops *ops, void *priv,
> +		   u64 req_addr, u64 req_range,
> +		   struct drm_gem_object *req_obj, u64 req_offset)
> +{
> +	DRM_GPUVA_ITER(it, mgr);
> +	int (*step)(struct drm_gpuva_op *, void *);
> +	struct drm_gpuva *va, *prev = NULL;
> +	u64 req_end = req_addr + req_range;
> +	bool skip_pmerge = false, skip_nmerge = false;
> +	int ret;
> +
> +	step = ops->sm_map_step;
> +
> +	if (unlikely(!drm_gpuva_in_mm_range(mgr, req_addr, req_range)))
> +		return -EINVAL;
> +
> +	if (unlikely(drm_gpuva_in_kernel_region(mgr, req_addr, req_range)))
> +		return -EINVAL;
> +
> +	if ((mgr->flags & DRM_GPUVA_MANAGER_REGIONS) &&
> +	    !drm_gpuva_in_any_region(mgr, req_addr, req_range))
> +		return -EINVAL;
> +
> +	drm_gpuva_iter_for_each_range(it, req_addr, req_end) {
> +		struct drm_gpuva *va = it.va;
> +		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 = gpuva_should_merge(va);
> +
> +		/* 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) {
> +			merge &= obj == req_obj &&
> +				 offset == req_offset;
> +
> +			if (end == req_end) {
> +				if (merge)
> +					goto done;
> +
> +				ret = op_unmap_cb(step, priv, va, false);
> +				if (ret)
> +					return ret;
> +				break;
> +			}
> +
> +			if (end < req_end) {
> +				skip_nmerge = false;
> +				ret = op_unmap_cb(step, 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 };
> +
> +				if (merge)
> +					goto done;
> +
> +				ret = op_remap_cb(step, 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;
> +
> +			if (end == req_end) {
> +				if (merge)
> +					goto done;
> +
> +				ret = op_remap_cb(step, priv, &p, NULL, &u);
> +				if (ret)
> +					return ret;
> +				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;
> +					ret = op_unmap_cb(step, priv, va, true);
> +					if (ret)
> +						return ret;
> +					goto next;
> +				}
> +
> +				ret = op_remap_cb(step, 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,
> +				};
> +
> +				if (merge)
> +					goto done;
> +
> +				ret = op_remap_cb(step, 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 (!prev)
> +				skip_pmerge = false;
> +
> +			if (end == req_end) {
> +				ret = op_unmap_cb(step, priv, va, merge);
> +				if (ret)
> +					return ret;
> +				break;
> +			}
> +
> +			if (end < req_end) {
> +				skip_nmerge = false;
> +				ret = op_unmap_cb(step, 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 };
> +				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;
> +					ret = op_unmap_cb(step, priv, va, true);
> +					if (ret)
> +						return ret;
> +					break;
> +				}
> +
> +				ret = op_remap_cb(step, priv, NULL, &n, &u);
> +				if (ret)
> +					return ret;
> +				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->va.addr;
> +		u64 range = va->va.range;
> +		u64 new_offset = offset;
> +		u64 new_addr = addr;
> +		u64 new_range = req_range + range;
> +		bool merge = gpuva_should_merge(va) &&
> +			     obj == req_obj &&
> +			     offset + range == req_offset;
> +
> +		if (mgr->flags & DRM_GPUVA_MANAGER_REGIONS)
> +			merge &= drm_gpuva_in_any_region(mgr, new_addr,
> +							 new_range);
> +
> +		if (merge) {
> +			ret = op_unmap_cb(step, priv, va, true);
> +			if (ret)
> +				return ret;
> +
> +			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->va.addr;
> +		u64 range = va->va.range;
> +		u64 end = addr + range;
> +		u64 new_range = req_range + range;
> +		u64 new_end = end;
> +		bool merge = gpuva_should_merge(va) &&
> +			     obj == req_obj &&
> +			     offset == req_offset + req_range;
> +
> +		if (mgr->flags & DRM_GPUVA_MANAGER_REGIONS)
> +			merge &= drm_gpuva_in_any_region(mgr, req_addr,
> +							 new_range);
> +
> +		if (merge) {
> +			ret = op_unmap_cb(step, priv, va, true);
> +			if (ret)
> +				return ret;
> +
> +			req_range = new_range;
> +			req_end = new_end;
> +		}
> +	}
> +
> +	ret = op_map_cb(step, priv,
> +			req_addr, req_range,
> +			req_obj, req_offset);
> +	if (ret)
> +		return ret;
> +
> +done:
> +	return 0;
> +}
> +
> +static int
> +__drm_gpuva_sm_unmap(struct drm_gpuva_manager *mgr,
> +		     struct drm_gpuva_fn_ops *ops, void *priv,
> +		     u64 req_addr, u64 req_range)
> +{
> +	DRM_GPUVA_ITER(it, mgr);
> +	int (*step)(struct drm_gpuva_op *, void *);
> +	u64 req_end = req_addr + req_range;
> +	int ret;
> +
> +	step = ops->sm_unmap_step;
> +
> +	drm_gpuva_iter_for_each_range(it, req_addr, req_end) {
> +		struct drm_gpuva *va = it.va;
> +		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(step, priv, &prev, &next, &unmap);
> +			if (ret)
> +				return ret;
> +		} else {
> +			ret = op_unmap_cb(step, priv, va, false);
> +			if (ret)
> +				return ret;
> +		}
> +	}
> +
> +	return 0;
> +}
> +
> +/**
> + * drm_gpuva_sm_map - creates the &drm_gpuva_op split/merge steps
> + * @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
> + * @priv: pointer to a driver private data structure
> + *
> + * This function iterates the given range of the GPU VA space. It utilizes the
> + * &drm_gpuva_fn_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_gpuva_sm_unmap is allowed to
> + * be called before the &drm_gpuva_manager's view of the GPU VA space was
> + * updated with the previous set of operations. 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.
> + *
> + * 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, 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.
> + *
> + * Returns: 0 on success or a negative error code
> + */
> +int
> +drm_gpuva_sm_map(struct drm_gpuva_manager *mgr, void *priv,
> +		 u64 req_addr, u64 req_range,
> +		 struct drm_gem_object *req_obj, u64 req_offset)
> +{
> +	if (!mgr->ops || !mgr->ops->sm_map_step)
> +		return -EINVAL;
> +
> +	return __drm_gpuva_sm_map(mgr, mgr->ops, priv,
> +				  req_addr, req_range,
> +				  req_obj, req_offset);
> +}
> +EXPORT_SYMBOL(drm_gpuva_sm_map);
> +
> +/**
> + * drm_gpuva_sm_unmap - 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
> + * @ops: the &drm_gpuva_fn_ops callbacks to provide the split/merge steps
> + * @priv: pointer to a driver private data structure
> + *
> + * This function iterates the given range of the GPU VA space. It utilizes the
> + * &drm_gpuva_fn_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_gpuva_sm_map is allowed to be
> + * called before the &drm_gpuva_manager's view of the GPU VA space was updated
> + * with the previous set of operations. 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.
> + *
> + * 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_gpuva_sm_unmap(struct drm_gpuva_manager *mgr, void *priv,
> +		   u64 req_addr, u64 req_range)
> +{
> +	if (!mgr->ops || !mgr->ops->sm_unmap_step)
> +		return -EINVAL;
> +
> +	return __drm_gpuva_sm_unmap(mgr, mgr->ops, priv,
> +				    req_addr, req_range);
> +}
> +EXPORT_SYMBOL(drm_gpuva_sm_unmap);
> +
> +static struct drm_gpuva_op *
> +gpuva_op_alloc(struct drm_gpuva_manager *mgr)
> +{
> +	struct drm_gpuva_fn_ops *fn = mgr->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_gpuva_manager *mgr,
> +	      struct drm_gpuva_op *op)
> +{
> +	struct drm_gpuva_fn_ops *fn = mgr->ops;
> +
> +	if (fn && fn->op_free)
> +		fn->op_free(op);
> +	else
> +		kfree(op);
> +}
> +
> +int drm_gpuva_sm_step(struct drm_gpuva_op *__op, void *priv)
> +{
> +	struct {
> +		struct drm_gpuva_manager *mgr;
> +		struct drm_gpuva_ops *ops;
> +	} *args = priv;
> +	struct drm_gpuva_manager *mgr = args->mgr;
> +	struct drm_gpuva_ops *ops = args->ops;
> +	struct drm_gpuva_op *op;
> +
> +	op = gpuva_op_alloc(mgr);
> +	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(mgr, op);
> +err:
> +	return -ENOMEM;
> +}
> +
> +static struct drm_gpuva_fn_ops gpuva_list_ops = {
> +	.sm_map_step = drm_gpuva_sm_step,
> +	.sm_unmap_step = drm_gpuva_sm_step,
> +};
> +
> +/**
> + * 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 {
> +		struct drm_gpuva_manager *mgr;
> +		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.mgr = mgr;
> +	args.ops = ops;
> +
> +	ret = __drm_gpuva_sm_map(mgr, &gpuva_list_ops, &args,
> +				 req_addr, req_range,
> +				 req_obj, req_offset);
> +	if (ret) {
> +		kfree(ops);
> +		return ERR_PTR(ret);
> +	}
> +
> +	return ops;
> +}
> +EXPORT_SYMBOL(drm_gpuva_sm_map_ops_create);
> +
> +/**
> + * 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 {
> +		struct drm_gpuva_manager *mgr;
> +		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.mgr = mgr;
> +	args.ops = ops;
> +
> +	ret = __drm_gpuva_sm_unmap(mgr, &gpuva_list_ops, &args,
> +				   req_addr, req_range);
> +	if (ret) {
> +		kfree(ops);
> +		return ERR_PTR(ret);
> +	}
> +
> +	return ops;
> +}
> +EXPORT_SYMBOL(drm_gpuva_sm_unmap_ops_create);
> +
> +/**
> + * drm_gpuva_prefetch_ops_create - creates the &drm_gpuva_ops to prefetch
> + * @mgr: the &drm_gpuva_manager representing the GPU VA space
> + * @req_addr: the start address of the range to prefetch
> + * @req_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_gpuva_prefetch_ops_create(struct drm_gpuva_manager *mgr,
> +			      u64 addr, u64 range)
> +{
> +	DRM_GPUVA_ITER(it, mgr);
> +	struct drm_gpuva_ops *ops;
> +	struct drm_gpuva_op *op;
> +	int ret;
> +
> +	ops = kzalloc(sizeof(*ops), GFP_KERNEL);
> +	if (!ops)
> +		return ERR_PTR(-ENOMEM);
> +
> +	INIT_LIST_HEAD(&ops->list);
> +
> +	drm_gpuva_iter_for_each_range(it, addr, addr + range) {
> +		op = gpuva_op_alloc(mgr);
> +		if (!op) {
> +			ret = -ENOMEM;
> +			goto err_free_ops;
> +		}
> +
> +		op->op = DRM_GPUVA_OP_PREFETCH;
> +		op->prefetch.va = it.va;
> +		list_add_tail(&op->entry, &ops->list);
> +	}
> +
> +	return ops;
> +
> +err_free_ops:
> +	drm_gpuva_ops_free(mgr, ops);
> +	return ERR_PTR(ret);
> +}
> +EXPORT_SYMBOL(drm_gpuva_prefetch_ops_create);
> +
> +/**
> + * drm_gpuva_gem_unmap_ops_create - creates the &drm_gpuva_ops to unmap a GEM
> + * @mgr: the &drm_gpuva_manager 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.
> + *
> + * Returns: a pointer to the &drm_gpuva_ops on success, an ERR_PTR on failure
> + */
> +struct drm_gpuva_ops *
> +drm_gpuva_gem_unmap_ops_create(struct drm_gpuva_manager *mgr,
> +			       struct drm_gem_object *obj)
> +{
> +	struct drm_gpuva_ops *ops;
> +	struct drm_gpuva_op *op;
> +	struct drm_gpuva *va;
> +	int ret;
> +
> +	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(mgr);
> +		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(mgr, ops);
> +	return ERR_PTR(ret);
> +}
> +EXPORT_SYMBOL(drm_gpuva_gem_unmap_ops_create);
> +
> +
> +/**
> + * drm_gpuva_ops_free - free the given &drm_gpuva_ops
> + * @mgr: the &drm_gpuva_manager 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_gpuva_manager *mgr,
> +		   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(mgr, op);
> +	}
> +
> +	kfree(ops);
> +}
> +EXPORT_SYMBOL(drm_gpuva_ops_free);
> diff --git a/include/drm/drm_drv.h b/include/drm/drm_drv.h
> index 1d76d0686b03..4fe4a1552948 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..d245d01e37a9
> --- /dev/null
> +++ b/include/drm/drm_gpuva_mgr.h
> @@ -0,0 +1,714 @@
> +/* 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 <linux/maple_tree.h>
> +#include <linux/mm.h>
> +#include <linux/rbtree.h>
> +#include <linux/spinlock.h>
> +#include <linux/types.h>
> +
> +struct drm_gpuva_manager;
> +struct drm_gpuva_fn_ops;
> +
> +/**
> + * 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.
> + *
> + * GPU VA mappings, represented by &drm_gpuva objects, are restricted to be
> + * placed within a &drm_gpuva_region.
> + */
> +struct drm_gpuva_region {
> +	/**
> +	 * @mgr: the &drm_gpuva_manager this object is associated with
> +	 */
> +	struct drm_gpuva_manager *mgr;
> +
> +	/**
> +	 * @va: structure containing the address and range of the &drm_gpuva_region
> +	 */
> +	struct {
> +		/**
> +		 * @addr: the start address
> +		 */
> +		u64 addr;
> +
> +		/*
> +		 * @range: the range
> +		 */
> +		u64 range;
> +	} va;
> +
> +	/**
> +	 * @sparse: indicates whether this region is sparse
> +	 */
> +	bool sparse;
> +};
> +
> +int drm_gpuva_region_insert(struct drm_gpuva_manager *mgr,
> +			    struct drm_gpuva_region *reg);
> +void drm_gpuva_region_remove(struct drm_gpuva_region *reg);
> +
> +bool
> +drm_gpuva_region_empty(struct drm_gpuva_region *reg);
> +
> +struct drm_gpuva_region *
> +drm_gpuva_region_find(struct drm_gpuva_manager *mgr,
> +		      u64 addr, u64 range);
> +struct drm_gpuva_region *
> +drm_gpuva_region_find_first(struct drm_gpuva_manager *mgr,
> +			    u64 addr, u64 range);
> +
> +/**
> + * enum drm_gpuva_flags - flags for struct drm_gpuva
> + */
> +enum drm_gpuva_flags {
> +	/**
> +	 * @DRM_GPUVA_EVICTED:
> +	 *
> +	 * Flag indicating that the &drm_gpuva's backing GEM is evicted.
> +	 */
> +	DRM_GPUVA_EVICTED = (1 << 0),
> +
> +	/**
> +	 * @DRM_GPUVA_USERBITS: user defined bits
> +	 */
> +	DRM_GPUVA_USERBITS = (1 << 1),
> +};
> +
> +/**
> + * 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.
> + *
> + * Typically, this structure is embedded in bigger driver structures.
> + */
> +struct drm_gpuva {
> +	/**
> +	 * @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;
> +
> +	/**
> +	 * @va: structure containing the address and range of the &drm_gpuva
> +	 */
> +	struct {
> +		/**
> +		 * @addr: the start address
> +		 */
> +		u64 addr;
> +
> +		/*
> +		 * @range: the range
> +		 */
> +		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 mapped &drm_gem_object
> +		 */
> +		struct drm_gem_object *obj;
> +	} gem;
> +};
> +
> +void drm_gpuva_link(struct drm_gpuva *va);
> +void drm_gpuva_unlink(struct drm_gpuva *va);
> +
> +int drm_gpuva_insert(struct drm_gpuva_manager *mgr,
> +		     struct drm_gpuva *va);
> +void drm_gpuva_remove(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_first(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_evict - sets whether the backing GEM of this &drm_gpuva is evicted
> + * @va: the &drm_gpuva to set the evict flag for
> + * @evict: indicates whether the &drm_gpuva is evicted
> + */
> +static inline void drm_gpuva_evict(struct drm_gpuva *va, bool evict)
> +{
> +	if (evict)
> +		va->flags |= DRM_GPUVA_EVICTED;
> +	else
> +		va->flags &= ~DRM_GPUVA_EVICTED;
> +}
> +
> +/**
> + * drm_gpuva_evicted - indicates whether the backing BO of this &drm_gpuva
> + * is evicted
> + * @va: the &drm_gpuva to check
> + */
> +static inline bool drm_gpuva_evicted(struct drm_gpuva *va)
> +{
> +	return va->flags & DRM_GPUVA_EVICTED;
> +}
> +
> +/**
> + * enum drm_gpuva_mgr_flags - the feature flags for the &drm_gpuva_manager
> + */
> +enum drm_gpuva_mgr_flags {
> +	/**
> +	 * @DRM_GPUVA_MANAGER_REGIONS:
> +	 *
> +	 * Enable the &drm_gpuva_manager to separately track &drm_gpuva_regions.
> +	 *
> +	 * &drm_gpuva_regions represent a reserved portion of VA space drivers
> +	 * can create mappings in. If regions are enabled, &drm_gpuvas can be
> +	 * created within an existing &drm_gpuva_region only and merge
> +	 * operations never indicate merging over region boundaries.
> +	 */
> +	DRM_GPUVA_MANAGER_REGIONS = (1 << 0),
> +};
> +
> +/**
> + * struct drm_gpuva_manager - DRM GPU VA Manager
> + *
> + * The DRM GPU VA Manager keeps track of a GPU's virtual address space by using
> + * &maple_tree structures. 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_mt: the &maple_tree to track GPU VA regions
> +	 */
> +	struct maple_tree region_mt;
> +
> +	/**
> +	 * @va_mt: the &maple_tree to track GPU VA mappings
> +	 */
> +	struct maple_tree va_mt;
> +
> +	/**
> +	 * @kernel_alloc_region:
> +	 *
> +	 * &drm_gpuva_region representing the address space cutout reserved for
> +	 * the kernel
> +	 */
> +	struct drm_gpuva_region kernel_alloc_region;
> +
> +	/**
> +	 * @ops: &drm_gpuva_fn_ops providing the split/merge steps to drivers
> +	 */
> +	struct drm_gpuva_fn_ops *ops;
> +
> +	/**
> +	 * @flags: the feature flags of the &drm_gpuva_manager
> +	 */
> +	enum drm_gpuva_mgr_flags flags;
> +};
> +
> +void drm_gpuva_manager_init(struct drm_gpuva_manager *mgr,
> +			    const char *name,
> +			    u64 start_offset, u64 range,
> +			    u64 reserve_offset, u64 reserve_range,
> +			    struct drm_gpuva_fn_ops *ops,
> +			    enum drm_gpuva_mgr_flags flags);
> +void drm_gpuva_manager_destroy(struct drm_gpuva_manager *mgr);
> +
> +/**
> + * struct drm_gpuva_iterator - iterator for walking the internal (maple) tree
> + */
> +struct drm_gpuva_iterator {
> +	/**
> +	 * @mas: the maple tree iterator (maple advanced state)
> +	 */
> +	struct ma_state mas;
> +
> +	/**
> +	 * @mgr: the &drm_gpuva_manager to iterate
> +	 */
> +	struct drm_gpuva_manager *mgr;
> +
> +	union {
> +		/**
> +		 * @va: the current &drm_gpuva entry
> +		 */
> +		struct drm_gpuva *va;
> +
> +		/**
> +		 * @reg: the current &drm_gpuva_region entry
> +		 */
> +		struct drm_gpuva_region *reg;
> +
> +		/**
> +		 * @entry: the current entry
> +		 */
> +		void *entry;
> +	};
> +};
> +
> +void drm_gpuva_iter_remove(struct drm_gpuva_iterator *it);
> +
> +/**
> + * DRM_GPUVA_ITER - create an iterator structure to iterate the &drm_gpuva tree
> + * @name: the name of the &drm_gpuva_iterator to create
> + * @mgr: the &drm_gpuva_manager to iterate
> + */
> +#define DRM_GPUVA_ITER(name, mgr__)				\
> +	struct drm_gpuva_iterator name = {			\
> +		.mas = __MA_STATE(&(mgr__)->va_mt, 0, 0),	\
> +		.mgr = mgr__,					\
> +		.va = NULL,					\
> +	}
> +
> +/**
> + * DRM_GPUVA_REGION_ITER - create an iterator structure to iterate the
> + * &drm_gpuva_region tree
> + * @name: the name of the &drm_gpuva_iterator to create
> + * @mgr: the &drm_gpuva_manager to iterate
> + */
> +#define DRM_GPUVA_REGION_ITER(name, mgr__)			\
> +	struct drm_gpuva_iterator name = {			\
> +		.mas = __MA_STATE(&(mgr__)->region_mt, 0, 0),	\
> +		.mgr = mgr__,					\
> +		.reg = NULL,					\
> +	}
> +
> +/**
> + * drm_gpuva_iter_for_each_range - iternator to walk over a range of entries
> + * @it__: &drm_gpuva_iterator structure to assign to in each iteration step
> + * @start__: starting offset, the first entry will overlap this
> + * @end__: ending offset, the last entry will start before this (but may overlap)
> + *
> + * This function can be used to iterate both &drm_gpuva objects and
> + * &drm_gpuva_region objects.
> + *
> + * It is safe against the removal of elements using &drm_gpuva_iter_remove,
> + * however it is not safe against the removal of elements using
> + * &drm_gpuva_remove and &drm_gpuva_region_remove.
> + */
> +#define drm_gpuva_iter_for_each_range(it__, start__, end__) \
> +	for ((it__).mas.index = start__, (it__).entry = mas_find(&(it__).mas, end__ - 1); \
> +	     (it__).entry; (it__).entry = mas_find(&(it__).mas, end__ - 1))
> +
> +/**
> + * drm_gpuva_iter_for_each - iternator to walk over all existing entries
> + * @it__: &drm_gpuva_iterator structure to assign to in each iteration step
> + *
> + * This function can be used to iterate both &drm_gpuva objects and
> + * &drm_gpuva_region objects.
> + *
> + * It is safe against the removal of elements using &drm_gpuva_iter_remove,
> + * however it is not safe against the removal of elements using
> + * &drm_gpuva_remove and &drm_gpuva_region_remove.
> + */
> +#define drm_gpuva_iter_for_each(it__) \
> +	drm_gpuva_iter_for_each_range(it__, (it__).mgr->mm_start, \
> +				      (it__).mgr->mm_start + (it__).mgr->mm_range)
> +
> +/**
> + * enum drm_gpuva_op_type - GPU VA operation type
> + *
> + * Operations to alter the GPU VA mappings tracked by the &drm_gpuva_manager.
> + */
> +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,
> +
> +	/**
> +	 * @DRM_GPUVA_OP_PREFETCH: the prefetch op type
> +	 */
> +	DRM_GPUVA_OP_PREFETCH,
> +};
> +
> +/**
> + * 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_prefetch - GPU VA prefetch operation
> + *
> + * This structure represents a single prefetch operation generated by the
> + * DRM GPU VA manager.
> + */
> +struct drm_gpuva_op_prefetch {
> +	/**
> +	 * @va: the &drm_gpuva to prefetch
> +	 */
> +	struct drm_gpuva *va;
> +};
> +
> +/**
> + * struct drm_gpuva_op - GPU VA operation
> + *
> + * This structure represents a single generic operation.
> + *
> + * 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;
> +
> +		/**
> +		 * @remap: the remap operation
> +		 */
> +		struct drm_gpuva_op_remap remap;
> +
> +		/**
> +		 * @unmap: the unmap operation
> +		 */
> +		struct drm_gpuva_op_unmap unmap;
> +
> +		/**
> +		 * @prefetch: the prefetch operation
> +		 */
> +		struct drm_gpuva_op_prefetch prefetch;
> +	};
> +};
> +
> +/**
> + * 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 &drm_gpuva_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 &drm_gpuva_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)
> +
> +/**
> + * drm_gpuva_for_each_op_from_reverse - iterate backwards from the given point
> + * @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 beginning
> + * from the given operation in reverse order.
> + */
> +#define drm_gpuva_for_each_op_from_reverse(op, ops) \
> +	list_for_each_entry_from_reverse(op, &(ops)->list, entry)
> +
> +/**
> + * drm_gpuva_first_op - returns the first &drm_gpuva_op from &drm_gpuva_ops
> + * @ops: the &drm_gpuva_ops to get the fist &drm_gpuva_op from
> + */
> +#define drm_gpuva_first_op(ops) \
> +	list_first_entry(&(ops)->list, struct drm_gpuva_op, entry)
> +
> +/**
> + * drm_gpuva_last_op - returns the last &drm_gpuva_op from &drm_gpuva_ops
> + * @ops: the &drm_gpuva_ops to get the last &drm_gpuva_op from
> + */
> +#define drm_gpuva_last_op(ops) \
> +	list_last_entry(&(ops)->list, struct drm_gpuva_op, entry)
> +
> +/**
> + * drm_gpuva_prev_op - previous &drm_gpuva_op in the list
> + * @op: the current &drm_gpuva_op
> + */
> +#define drm_gpuva_prev_op(op) list_prev_entry(op, entry)
> +
> +/**
> + * drm_gpuva_next_op - next &drm_gpuva_op in the list
> + * @op: the current &drm_gpuva_op
> + */
> +#define drm_gpuva_next_op(op) list_next_entry(op, 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);
> +
> +struct drm_gpuva_ops *
> +drm_gpuva_prefetch_ops_create(struct drm_gpuva_manager *mgr,
> +				 u64 addr, u64 range);
> +
> +struct drm_gpuva_ops *
> +drm_gpuva_gem_unmap_ops_create(struct drm_gpuva_manager *mgr,
> +			       struct drm_gem_object *obj);
> +
> +void drm_gpuva_ops_free(struct drm_gpuva_manager *mgr,
> +			struct drm_gpuva_ops *ops);
> +
> +/**
> + * struct drm_gpuva_fn_ops - callbacks for split/merge steps
> + *
> + * This structure defines the callbacks used by &drm_gpuva_sm_map and
> + * &drm_gpuva_sm_unmap to provide the split/merge steps for map and unmap
> + * operations to drivers.
> + */
> +struct drm_gpuva_fn_ops {
> +	/**
> +	 * @op_alloc: called when the &drm_gpuva_manager allocates
> +	 * a struct drm_gpuva_op
> +	 *
> +	 * Some drivers may want to embed struct drm_gpuva_op into driver
> +	 * specific structures. By implementing this callback drivers can
> +	 * allocate memory accordingly.
> +	 *
> +	 * This callback is optional.
> +	 */
> +	struct drm_gpuva_op *(*op_alloc)(void);
> +
> +	/**
> +	 * @op_free: called when the &drm_gpuva_manager frees a
> +	 * struct drm_gpuva_op
> +	 *
> +	 * Some drivers may want to embed struct drm_gpuva_op into driver
> +	 * specific structures. By implementing this callback drivers can
> +	 * free the previously allocated memory accordingly.
> +	 *
> +	 * This callback is optional.
> +	 */
> +	void (*op_free)(struct drm_gpuva_op *op);
> +
> +	/**
> +	 * @sm_map_step: called from &drm_gpuva_sm_map providing the split and
> +	 * merge steps
> +	 *
> +	 * This callback provides a single split / merge step or, if no split
> +	 * and merge is indicated, the original map operation.
> +	 *
> +	 * The &priv pointer is equal to the one drivers pass to
> +	 * &drm_gpuva_sm_map.
> +	 */
> +	int (*sm_map_step)(struct drm_gpuva_op *op, void *priv);
> +
> +	/**
> +	 * @sm_unmap_step: called from &drm_gpuva_sm_map providing the split and
> +	 * merge steps
> +	 *
> +	 * This callback provides a single split step or, if no split is
> +	 * indicated, the plain unmap operations of the corresponding unmap
> +	 * range originally passed to &drm_gpuva_sm_unmap.
> +	 *
> +	 * The &priv pointer is equal to the one drivers pass to
> +	 * &drm_gpuva_sm_unmap.
> +	 */
> +	int (*sm_unmap_step)(struct drm_gpuva_op *op, void *priv);
> +};
> +
> +int drm_gpuva_sm_map(struct drm_gpuva_manager *mgr, void *priv,
> +		     u64 addr, u64 range,
> +		     struct drm_gem_object *obj, u64 offset);
> +
> +int drm_gpuva_sm_unmap(struct drm_gpuva_manager *mgr, void *priv,
> +		       u64 addr, u64 range);
> +
> +#endif /* __DRM_GPUVA_MGR_H__ */