summaryrefslogtreecommitdiffstats
path: root/Documentation/gpu/rfc
diff options
context:
space:
mode:
authorLinus Torvalds <torvalds@linux-foundation.org>2026-08-30 09:22:00 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2026-08-30 09:22:00 -0700
commit034dd340b08be1f2f0477ad16131d609f9dbd53c (patch)
tree2536f4b2d7893ccd916b5abdf3c454ad6edc03c2 /Documentation/gpu/rfc
downloadlinux-stable-034dd340b08be1f2f0477ad16131d609f9dbd53c.tar.gz
linux-stable-034dd340b08be1f2f0477ad16131d609f9dbd53c.zip
Merge tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-tracegrafted
Pull tracing fixes from Steven Rostedt: - Fix error output of boot instance creation failure Currently if a boot instance creation fails, instead of printing out the name of the instance that failed, it prints "(null)". That is because it prints "cur_str" that had already been processed by strsep(). Print the saved name instead. While at it, print the error code of the failure. - Fix use-after-free for same named historgrams Histograms can be named so that they can be used in multiple events. But if the named histogram has a variable attached, the second event that uses the named histogram which duplicates it and needs to free the original after duplication leaves the old variable in place and still visible. If another histogram uses than variable, it will use the stale one which will try to reference the freed duplicate histogram and crash the kernel. Free the duplicate variables along with the duplicated histogram data. - Check return value of kthread_run() in event self test The events self tests uses a kthread for testing but does not check if it succeeded in creating a kthread. If the kthread creation were to fail, the code will still try to call kthread_stop() on the error returned. - Fix race between reading trace_pipe and updating subbuffer size If a user is reading the trace_pipe file at the same time they update the ring buffer sub-buffer size, can cause the trace_pipe read to read stale data. Add trace_access_lock() around updating the ring buffer sub-buffer size. - Fix eventfs_inode on failure path in creation of the events directory In the creation of the "events" directory, if after allocating the eventfs_inode a failure is detected, it calls cleanup_ei() which calls free_ei(). The free_ei() will test if eventfs_inode being freed has no children. It is a bug if it does. But on the failure case of the creation of the "events" directory, the children lists have not yet been initialized and the free will trigger a warning because list_empty() on an uninitialized list returns false. Move the initialization into init_ei() where it makes more sense and makes sure that a created eventfs_inode has its lists initialized upon creation. - Check return value of kthread_run() in ftrace direct sample code The sample code that shows how to use the ftrace direct calls does not test the return of kthread_run() to see if it succeeds. Return a failure if the kthread_run() doesn't succeed. - Clear user events state on fork in case of alloc failure On fork, the child gets a pointer to the parent's user events state. It makes a copy of it then updates the child's pointer to it. But if the allocation fails, the duplication function leaves the child with a pointer to its parent's descriptor. When the child cleans up its data, it will free the parent's descriptor while the parent is still using it. In the duplication function, set the child's user_event_mm to NULL before testing if the allocation succeeded, and when it exits it will not free the parent's descriptor. - Fix retry exhaustion in simple ring buffer reader swap simple_ring_buffer_swap_reader_page() starts with retry set to 8 and post-decrements it only after a failed link replacement. On the final attempt, a successful replacement leaves retry at zero, while a failed replacement leaves it at -1. But the check for success expects the retry value to be non-zero and exits with an error on zero. This is the opposite result. Fix it. - Fail nicely when the remote swap_reader_page() returns an error Currently, if the swap_reader_page() of a remote buffer fails, it triggers a WARN_ON_ONCE() and continues normally. Instead, have it exit with an error and a pr_warn() print instead of a full WARNING. * tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: ring-buffer: Stop remote reader update when page swap fails tracing: Fix retry exhaustion in simple ring buffer reader swap tracing/user_events: Clear copied tracing state before fork duplication samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-multi-modify samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-modify eventfs: Initialize ei->children and ei->list in init_ei() tracing: Fix use-after-free in trace_pipe read on sub-buffer order change tracing: Fix crash passing ERR_PTR to kthread_stop() tracing: Fix use-after-free with same-name named triggers tracing: Fix logged instance name on creation failure
Diffstat (limited to 'Documentation/gpu/rfc')
-rw-r--r--Documentation/gpu/rfc/color_pipeline.rst378
-rw-r--r--Documentation/gpu/rfc/gpusvm.rst118
-rw-r--r--Documentation/gpu/rfc/i915_gem_lmem.rst22
-rw-r--r--Documentation/gpu/rfc/i915_scheduler.rst152
-rw-r--r--Documentation/gpu/rfc/i915_small_bar.h189
-rw-r--r--Documentation/gpu/rfc/i915_small_bar.rst47
-rw-r--r--Documentation/gpu/rfc/i915_vm_bind.h290
-rw-r--r--Documentation/gpu/rfc/i915_vm_bind.rst245
-rw-r--r--Documentation/gpu/rfc/index.rst26
9 files changed, 1467 insertions, 0 deletions
diff --git a/Documentation/gpu/rfc/color_pipeline.rst b/Documentation/gpu/rfc/color_pipeline.rst
new file mode 100644
index 000000000..cd1cc2d0f
--- /dev/null
+++ b/Documentation/gpu/rfc/color_pipeline.rst
@@ -0,0 +1,378 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+========================
+Linux Color Pipeline API
+========================
+
+What problem are we solving?
+============================
+
+We would like to support pre-, and post-blending complex color
+transformations in display controller hardware in order to allow for
+HW-supported HDR use-cases, as well as to provide support to
+color-managed applications, such as video or image editors.
+
+It is possible to support an HDR output on HW supporting the Colorspace
+and HDR Metadata drm_connector properties, but that requires the
+compositor or application to render and compose the content into one
+final buffer intended for display. Doing so is costly.
+
+Most modern display HW offers various 1D LUTs, 3D LUTs, matrices, and other
+operations to support color transformations. These operations are often
+implemented in fixed-function HW and therefore much more power efficient than
+performing similar operations via shaders or CPU.
+
+We would like to make use of this HW functionality to support complex color
+transformations with no, or minimal CPU or shader load. The switch between HW
+fixed-function blocks and shaders/CPU must be seamless with no visible
+difference when fallback to shaders/CPU is neceesary at any time.
+
+
+How are other OSes solving this problem?
+========================================
+
+The most widely supported use-cases regard HDR content, whether video or
+gaming.
+
+Most OSes will specify the source content format (color gamut, encoding transfer
+function, and other metadata, such as max and average light levels) to a driver.
+Drivers will then program their fixed-function HW accordingly to map from a
+source content buffer's space to a display's space.
+
+When fixed-function HW is not available the compositor will assemble a shader to
+ask the GPU to perform the transformation from the source content format to the
+display's format.
+
+A compositor's mapping function and a driver's mapping function are usually
+entirely separate concepts. On OSes where a HW vendor has no insight into
+closed-source compositor code such a vendor will tune their color management
+code to visually match the compositor's. On other OSes, where both mapping
+functions are open to an implementer they will ensure both mappings match.
+
+This results in mapping algorithm lock-in, meaning that no-one alone can
+experiment with or introduce new mapping algorithms and achieve
+consistent results regardless of which implementation path is taken.
+
+Why is Linux different?
+=======================
+
+Unlike other OSes, where there is one compositor for one or more drivers, on
+Linux we have a many-to-many relationship. Many compositors; many drivers.
+In addition each compositor vendor or community has their own view of how
+color management should be done. This is what makes Linux so beautiful.
+
+This means that a HW vendor can now no longer tune their driver to one
+compositor, as tuning it to one could make it look fairly different from
+another compositor's color mapping.
+
+We need a better solution.
+
+
+Descriptive API
+===============
+
+An API that describes the source and destination colorspaces is a descriptive
+API. It describes the input and output color spaces but does not describe
+how precisely they should be mapped. Such a mapping includes many minute
+design decision that can greatly affect the look of the final result.
+
+It is not feasible to describe such mapping with enough detail to ensure the
+same result from each implementation. In fact, these mappings are a very active
+research area.
+
+
+Prescriptive API
+================
+
+A prescriptive API describes not the source and destination colorspaces. It
+instead prescribes a recipe for how to manipulate pixel values to arrive at the
+desired outcome.
+
+This recipe is generally an ordered list of straight-forward operations,
+with clear mathematical definitions, such as 1D LUTs, 3D LUTs, matrices,
+or other operations that can be described in a precise manner.
+
+
+The Color Pipeline API
+======================
+
+HW color management pipelines can significantly differ between HW
+vendors in terms of availability, ordering, and capabilities of HW
+blocks. This makes a common definition of color management blocks and
+their ordering nigh impossible. Instead we are defining an API that
+allows user space to discover the HW capabilities in a generic manner,
+agnostic of specific drivers and hardware.
+
+
+drm_colorop Object
+==================
+
+To support the definition of color pipelines we define the DRM core
+object type drm_colorop. Individual drm_colorop objects will be chained
+via the NEXT property of a drm_colorop to constitute a color pipeline.
+Each drm_colorop object is unique, i.e., even if multiple color
+pipelines have the same operation they won't share the same drm_colorop
+object to describe that operation.
+
+Note that drivers are not expected to map drm_colorop objects statically
+to specific HW blocks. The mapping of drm_colorop objects is entirely a
+driver-internal detail and can be as dynamic or static as a driver needs
+it to be. See more in the Driver Implementation Guide section below.
+
+Each drm_colorop has three core properties:
+
+TYPE: An enumeration property, defining the type of transformation, such as
+* enumerated curve
+* custom (uniform) 1D LUT
+* 3x3 matrix
+* 3x4 matrix
+* 3D LUT
+* etc.
+
+Depending on the type of transformation other properties will describe
+more details.
+
+BYPASS: A boolean property that can be used to easily put a block into
+bypass mode. The BYPASS property is not mandatory for a colorop, as long
+as the entire pipeline can get bypassed by setting the COLOR_PIPELINE on
+a plane to '0'.
+
+NEXT: The ID of the next drm_colorop in a color pipeline, or 0 if this
+drm_colorop is the last in the chain.
+
+An example of a drm_colorop object might look like one of these::
+
+ /* 1D enumerated curve */
+ Color operation 42
+ ├─ "TYPE": immutable enum {1D enumerated curve, 1D LUT, 3x3 matrix, 3x4 matrix, 3D LUT, etc.} = 1D enumerated curve
+ ├─ "BYPASS": bool {true, false}
+ ├─ "CURVE_1D_TYPE": enum {sRGB EOTF, sRGB inverse EOTF, PQ EOTF, PQ inverse EOTF, …}
+ └─ "NEXT": immutable color operation ID = 43
+
+ /* custom 4k entry 1D LUT */
+ Color operation 52
+ ├─ "TYPE": immutable enum {1D enumerated curve, 1D LUT, 3x3 matrix, 3x4 matrix, 3D LUT, etc.} = 1D LUT
+ ├─ "BYPASS": bool {true, false}
+ ├─ "SIZE": immutable range = 4096
+ ├─ "DATA": blob
+ └─ "NEXT": immutable color operation ID = 0
+
+ /* 17^3 3D LUT */
+ Color operation 72
+ ├─ "TYPE": immutable enum {1D enumerated curve, 1D LUT, 3x3 matrix, 3x4 matrix, 3D LUT, etc.} = 3D LUT
+ ├─ "BYPASS": bool {true, false}
+ ├─ "SIZE": immutable range = 17
+ ├─ "DATA": blob
+ └─ "NEXT": immutable color operation ID = 73
+
+drm_colorop extensibility
+-------------------------
+
+Unlike existing DRM core objects, like &drm_plane, drm_colorop is not
+extensible. This simplifies implementations and keeps all functionality
+for managing &drm_colorop objects in the DRM core.
+
+If there is a need one may introduce a simple &drm_colorop_funcs
+function table in the future, for example to support an IN_FORMATS
+property on a &drm_colorop.
+
+If a driver requires the ability to create a driver-specific colorop
+object they will need to add &drm_colorop func table support with
+support for the usual functions, like destroy, atomic_duplicate_state,
+and atomic_destroy_state.
+
+
+COLOR_PIPELINE Plane Property
+=============================
+
+Color Pipelines are created by a driver and advertised via a new
+COLOR_PIPELINE enum property on each plane. Values of the property
+always include object id 0, which is the default and means all color
+processing is disabled. Additional values will be the object IDs of the
+first drm_colorop in a pipeline. A driver can create and advertise none,
+one, or more possible color pipelines. A DRM client will select a color
+pipeline by setting the COLOR PIPELINE to the respective value.
+
+NOTE: Many DRM clients will set enumeration properties via the string
+value, often hard-coding it. Since this enumeration is generated based
+on the colorop object IDs it is important to perform the Color Pipeline
+Discovery, described below, instead of hard-coding color pipeline
+assignment. Drivers might generate the enum strings dynamically.
+Hard-coded strings might only work for specific drivers on a specific
+pieces of HW. Color Pipeline Discovery can work universally, as long as
+drivers implement the required color operations.
+
+The COLOR_PIPELINE property is only exposed when the
+DRM_CLIENT_CAP_PLANE_COLOR_PIPELINE is set. Drivers shall ignore any
+existing pre-blend color operations when this cap is set, such as
+COLOR_RANGE and COLOR_ENCODING. If drivers want to support COLOR_RANGE
+or COLOR_ENCODING functionality when the color pipeline client cap is
+set, they are expected to expose colorops in the pipeline to allow for
+the appropriate color transformation.
+
+Setting of the COLOR_PIPELINE plane property or drm_colorop properties
+is only allowed for userspace that sets this client cap.
+
+An example of a COLOR_PIPELINE property on a plane might look like this::
+
+ Plane 10
+ ├─ "TYPE": immutable enum {Overlay, Primary, Cursor} = Primary
+ ├─ …
+ └─ "COLOR_PIPELINE": enum {0, 42, 52} = 0
+
+
+Color Pipeline Discovery
+========================
+
+A DRM client wanting color management on a drm_plane will:
+
+1. Get the COLOR_PIPELINE property of the plane
+2. iterate all COLOR_PIPELINE enum values
+3. for each enum value walk the color pipeline (via the NEXT pointers)
+ and see if the available color operations are suitable for the
+ desired color management operations
+
+If userspace encounters an unknown or unsuitable color operation during
+discovery it does not need to reject the entire color pipeline outright,
+as long as the unknown or unsuitable colorop has a "BYPASS" property.
+Drivers will ensure that a bypassed block does not have any effect.
+
+An example of chained properties to define an AMD pre-blending color
+pipeline might look like this::
+
+ Plane 10
+ ├─ "TYPE" (immutable) = Primary
+ └─ "COLOR_PIPELINE": enum {0, 44} = 0
+
+ Color operation 44
+ ├─ "TYPE" (immutable) = 1D enumerated curve
+ ├─ "BYPASS": bool
+ ├─ "CURVE_1D_TYPE": enum {sRGB EOTF, PQ EOTF} = sRGB EOTF
+ └─ "NEXT" (immutable) = 45
+
+ Color operation 45
+ ├─ "TYPE" (immutable) = 3x4 Matrix
+ ├─ "BYPASS": bool
+ ├─ "DATA": blob
+ └─ "NEXT" (immutable) = 46
+
+ Color operation 46
+ ├─ "TYPE" (immutable) = 1D enumerated curve
+ ├─ "BYPASS": bool
+ ├─ "CURVE_1D_TYPE": enum {sRGB Inverse EOTF, PQ Inverse EOTF} = sRGB EOTF
+ └─ "NEXT" (immutable) = 47
+
+ Color operation 47
+ ├─ "TYPE" (immutable) = 1D LUT
+ ├─ "SIZE": immutable range = 4096
+ ├─ "DATA": blob
+ └─ "NEXT" (immutable) = 48
+
+ Color operation 48
+ ├─ "TYPE" (immutable) = 3D LUT
+ ├─ "DATA": blob
+ └─ "NEXT" (immutable) = 49
+
+ Color operation 49
+ ├─ "TYPE" (immutable) = 1D enumerated curve
+ ├─ "BYPASS": bool
+ ├─ "CURVE_1D_TYPE": enum {sRGB EOTF, PQ EOTF} = sRGB EOTF
+ └─ "NEXT" (immutable) = 0
+
+
+Color Pipeline Programming
+==========================
+
+Once a DRM client has found a suitable pipeline it will:
+
+1. Set the COLOR_PIPELINE enum value to the one pointing at the first
+ drm_colorop object of the desired pipeline
+2. Set the properties for all drm_colorop objects in the pipeline to the
+ desired values, setting BYPASS to true for unused drm_colorop blocks,
+ and false for enabled drm_colorop blocks
+3. Perform (TEST_ONLY or not) atomic commit with all the other KMS
+ states it wishes to change
+
+To configure the pipeline for an HDR10 PQ plane and blending in linear
+space, a compositor might perform an atomic commit with the following
+property values::
+
+ Plane 10
+ └─ "COLOR_PIPELINE" = 42
+
+ Color operation 42
+ └─ "BYPASS" = true
+
+ Color operation 44
+ └─ "BYPASS" = true
+
+ Color operation 45
+ └─ "BYPASS" = true
+
+ Color operation 46
+ └─ "BYPASS" = true
+
+ Color operation 47
+ ├─ "DATA" = Gamut mapping + tone mapping + night mode
+ └─ "BYPASS" = false
+
+ Color operation 48
+ ├─ "CURVE_1D_TYPE" = PQ EOTF
+ └─ "BYPASS" = false
+
+
+Driver Implementer's Guide
+==========================
+
+What does this all mean for driver implementations? As noted above the
+colorops can map to HW directly but don't need to do so. Here are some
+suggestions on how to think about creating your color pipelines:
+
+- Try to expose pipelines that use already defined colorops, even if
+ your hardware pipeline is split differently. This allows existing
+ userspace to immediately take advantage of the hardware.
+
+- Additionally, try to expose your actual hardware blocks as colorops.
+ Define new colorop types where you believe it can offer significant
+ benefits if userspace learns to program them.
+
+- Avoid defining new colorops for compound operations with very narrow
+ scope. If you have a hardware block for a special operation that
+ cannot be split further, you can expose that as a new colorop type.
+ However, try to not define colorops for "use cases", especially if
+ they require you to combine multiple hardware blocks.
+
+- Design new colorops as prescriptive, not descriptive; by the
+ mathematical formula, not by the assumed input and output.
+
+A defined colorop type must be deterministic. The exact behavior of the
+colorop must be documented entirely, whether via a mathematical formula
+or some other description. Its operation can depend only on its
+properties and input and nothing else, allowed error tolerance
+notwithstanding.
+
+
+Driver Forward/Backward Compatibility
+=====================================
+
+As this is uAPI drivers can't regress color pipelines that have been
+introduced for a given HW generation. New HW generations are free to
+abandon color pipelines advertised for previous generations.
+Nevertheless, it can be beneficial to carry support for existing color
+pipelines forward as those will likely already have support in DRM
+clients.
+
+Introducing new colorops to a pipeline is fine, as long as they can be
+bypassed or are purely informational. DRM clients implementing support
+for the pipeline can always skip unknown properties as long as they can
+be confident that doing so will not cause unexpected results.
+
+If a new colorop doesn't fall into one of the above categories
+(bypassable or informational) the modified pipeline would be unusable
+for user space. In this case a new pipeline should be defined.
+
+
+References
+==========
+
+1. https://lore.kernel.org/dri-devel/QMers3awXvNCQlyhWdTtsPwkp5ie9bze_hD5nAccFW7a_RXlWjYB7MoUW_8CKLT2bSQwIXVi5H6VULYIxCdgvryZoAoJnC5lZgyK1QWn488=@emersion.fr/ \ No newline at end of file
diff --git a/Documentation/gpu/rfc/gpusvm.rst b/Documentation/gpu/rfc/gpusvm.rst
new file mode 100644
index 000000000..469db1372
--- /dev/null
+++ b/Documentation/gpu/rfc/gpusvm.rst
@@ -0,0 +1,118 @@
+.. SPDX-License-Identifier: (GPL-2.0+ OR MIT)
+
+===============
+GPU SVM Section
+===============
+
+Agreed upon design principles
+=============================
+
+* migrate_to_ram path
+ * Rely only on core MM concepts (migration PTEs, page references, and
+ page locking).
+ * No driver specific locks other than locks for hardware interaction in
+ this path. These are not required and generally a bad idea to
+ invent driver defined locks to seal core MM races.
+ * An example of a driver-specific lock causing issues occurred before
+ fixing do_swap_page to lock the faulting page. A driver-exclusive lock
+ in migrate_to_ram produced a stable livelock if enough threads read
+ the faulting page.
+ * Partial migration is supported (i.e., a subset of pages attempting to
+ migrate can actually migrate, with only the faulting page guaranteed
+ to migrate).
+ * Driver handles mixed migrations via retry loops rather than locking.
+* Eviction
+ * Eviction is defined as migrating data from the GPU back to the
+ CPU without a virtual address to free up GPU memory.
+ * Only looking at physical memory data structures and locks as opposed to
+ looking at virtual memory data structures and locks.
+ * No looking at mm/vma structs or relying on those being locked.
+ * The rationale for the above two points is that CPU virtual addresses
+ can change at any moment, while the physical pages remain stable.
+ * GPU page table invalidation, which requires a GPU virtual address, is
+ handled via the notifier that has access to the GPU virtual address.
+* GPU fault side
+ * mmap_read only used around core MM functions which require this lock
+ and should strive to take mmap_read lock only in GPU SVM layer.
+ * Big retry loop to handle all races with the mmu notifier under the gpu
+ pagetable locks/mmu notifier range lock/whatever we end up calling
+ those.
+ * Races (especially against concurrent eviction or migrate_to_ram)
+ should not be handled on the fault side by trying to hold locks;
+ rather, they should be handled using retry loops. One possible
+ exception is holding a BO's dma-resv lock during the initial migration
+ to VRAM, as this is a well-defined lock that can be taken underneath
+ the mmap_read lock.
+ * One possible issue with the above approach is if a driver has a strict
+ migration policy requiring GPU access to occur in GPU memory.
+ Concurrent CPU access could cause a livelock due to endless retries.
+ While no current user (Xe) of GPU SVM has such a policy, it is likely
+ to be added in the future. Ideally, this should be resolved on the
+ core-MM side rather than through a driver-side lock.
+* Physical memory to virtual backpointer
+ * This does not work, as no pointers from physical memory to virtual
+ memory should exist. mremap() is an example of the core MM updating
+ the virtual address without notifying the driver of address
+ change rather the driver only receiving the invalidation notifier.
+ * The physical memory backpointer (page->zone_device_data) should remain
+ stable from allocation to page free. Safely updating this against a
+ concurrent user would be very difficult unless the page is free.
+* GPU pagetable locking
+ * Notifier lock only protects range tree, pages valid state for a range
+ (rather than seqno due to wider notifiers), pagetable entries, and
+ mmu notifier seqno tracking, it is not a global lock to protect
+ against races.
+ * All races handled with big retry as mentioned above.
+
+Overview of baseline design
+===========================
+
+.. kernel-doc:: drivers/gpu/drm/drm_gpusvm.c
+ :doc: Overview
+
+.. kernel-doc:: drivers/gpu/drm/drm_gpusvm.c
+ :doc: Locking
+
+.. kernel-doc:: drivers/gpu/drm/drm_gpusvm.c
+ :doc: Partial Unmapping of Ranges
+
+.. kernel-doc:: drivers/gpu/drm/drm_gpusvm.c
+ :doc: Examples
+
+Overview of drm_pagemap design
+==============================
+
+.. kernel-doc:: drivers/gpu/drm/drm_pagemap.c
+ :doc: Overview
+
+.. kernel-doc:: drivers/gpu/drm/drm_pagemap.c
+ :doc: Migration
+
+Possible future design features
+===============================
+
+* Concurrent GPU faults
+ * CPU faults are concurrent so makes sense to have concurrent GPU
+ faults.
+ * Should be possible with fined grained locking in the driver GPU
+ fault handler.
+ * No expected GPU SVM changes required.
+* Ranges with mixed system and device pages
+ * Can be added if required to drm_gpusvm_get_pages fairly easily.
+* Multi-GPU support
+ * Work in progress and patches expected after initially landing on GPU
+ SVM.
+ * Ideally can be done with little to no changes to GPU SVM.
+* Drop ranges in favor of radix tree
+ * May be desirable for faster notifiers.
+* Compound device pages
+ * Nvidia, AMD, and Intel all have agreed expensive core MM functions in
+ migrate device layer are a performance bottleneck, having compound
+ device pages should help increase performance by reducing the number
+ of these expensive calls.
+* Higher order dma mapping for migration
+ * 4k dma mapping adversely affects migration performance on Intel
+ hardware, higher order (2M) dma mapping should help here.
+* Build common userptr implementation on top of GPU SVM
+* Driver side madvise implementation and migration policies
+* Pull in pending dma-mapping API changes from Leon / Nvidia when these land
diff --git a/Documentation/gpu/rfc/i915_gem_lmem.rst b/Documentation/gpu/rfc/i915_gem_lmem.rst
new file mode 100644
index 000000000..b421a3c18
--- /dev/null
+++ b/Documentation/gpu/rfc/i915_gem_lmem.rst
@@ -0,0 +1,22 @@
+=========================
+I915 DG1/LMEM RFC Section
+=========================
+
+Upstream plan
+=============
+For upstream the overall plan for landing all the DG1 stuff and turning it for
+real, with all the uAPI bits is:
+
+* Merge basic HW enabling of DG1(still without pciid)
+* Merge the uAPI bits behind special CONFIG_BROKEN(or so) flag
+ * At this point we can still make changes, but importantly this lets us
+ start running IGTs which can utilize local-memory in CI
+* Convert over to TTM, make sure it all keeps working. Some of the work items:
+ * TTM shrinker for discrete
+ * dma_resv_lockitem for full dma_resv_lock, i.e not just trylock
+ * Use TTM CPU pagefault handler
+ * Route shmem backend over to TTM SYSTEM for discrete
+ * TTM purgeable object support
+ * Move i915 buddy allocator over to TTM
+* Send RFC(with mesa-dev on cc) for final sign off on the uAPI
+* Add pciid for DG1 and turn on uAPI for real
diff --git a/Documentation/gpu/rfc/i915_scheduler.rst b/Documentation/gpu/rfc/i915_scheduler.rst
new file mode 100644
index 000000000..2974525f0
--- /dev/null
+++ b/Documentation/gpu/rfc/i915_scheduler.rst
@@ -0,0 +1,152 @@
+=========================================
+I915 GuC Submission/DRM Scheduler Section
+=========================================
+
+Upstream plan
+=============
+For upstream the overall plan for landing GuC submission and integrating the
+i915 with the DRM scheduler is:
+
+* Merge basic GuC submission
+ * Basic submission support for all gen11+ platforms
+ * Not enabled by default on any current platforms but can be enabled via
+ modparam enable_guc
+ * Lots of rework will need to be done to integrate with DRM scheduler so
+ no need to nit pick everything in the code, it just should be
+ functional, no major coding style / layering errors, and not regress
+ execlists
+ * Update IGTs / selftests as needed to work with GuC submission
+ * Enable CI on supported platforms for a baseline
+ * Rework / get CI heathly for GuC submission in place as needed
+* Merge new parallel submission uAPI
+ * Bonding uAPI completely incompatible with GuC submission, plus it has
+ severe design issues in general, which is why we want to retire it no
+ matter what
+ * New uAPI adds I915_CONTEXT_ENGINES_EXT_PARALLEL context setup step
+ which configures a slot with N contexts
+ * After I915_CONTEXT_ENGINES_EXT_PARALLEL a user can submit N batches to
+ a slot in a single execbuf IOCTL and the batches run on the GPU in
+ parallel
+ * Initially only for GuC submission but execlists can be supported if
+ needed
+* Convert the i915 to use the DRM scheduler
+ * GuC submission backend fully integrated with DRM scheduler
+ * All request queues removed from backend (e.g. all backpressure
+ handled in DRM scheduler)
+ * Resets / cancels hook in DRM scheduler
+ * Watchdog hooks into DRM scheduler
+ * Lots of complexity of the GuC backend can be pulled out once
+ integrated with DRM scheduler (e.g. state machine gets
+ simpler, locking gets simpler, etc...)
+ * Execlists backend will minimum required to hook in the DRM scheduler
+ * Legacy interface
+ * Features like timeslicing / preemption / virtual engines would
+ be difficult to integrate with the DRM scheduler and these
+ features are not required for GuC submission as the GuC does
+ these things for us
+ * ROI low on fully integrating into DRM scheduler
+ * Fully integrating would add lots of complexity to DRM
+ scheduler
+ * Port i915 priority inheritance / boosting feature in DRM scheduler
+ * Used for i915 page flip, may be useful to other DRM drivers as
+ well
+ * Will be an optional feature in the DRM scheduler
+ * Remove in-order completion assumptions from DRM scheduler
+ * Even when using the DRM scheduler the backends will handle
+ preemption, timeslicing, etc... so it is possible for jobs to
+ finish out of order
+ * Pull out i915 priority levels and use DRM priority levels
+ * Optimize DRM scheduler as needed
+
+TODOs for GuC submission upstream
+=================================
+
+* Need an update to GuC firmware / i915 to enable error state capture
+* Open source tool to decode GuC logs
+* Public GuC spec
+
+New uAPI for basic GuC submission
+=================================
+No major changes are required to the uAPI for basic GuC submission. The only
+change is a new scheduler attribute: I915_SCHEDULER_CAP_STATIC_PRIORITY_MAP.
+This attribute indicates the 2k i915 user priority levels are statically mapped
+into 3 levels as follows:
+
+* -1k to -1 Low priority
+* 0 Medium priority
+* 1 to 1k High priority
+
+This is needed because the GuC only has 4 priority bands. The highest priority
+band is reserved with the kernel. This aligns with the DRM scheduler priority
+levels too.
+
+Spec references:
+----------------
+* https://www.khronos.org/registry/EGL/extensions/IMG/EGL_IMG_context_priority.txt
+* https://www.khronos.org/registry/vulkan/specs/1.2-extensions/html/chap5.html#devsandqueues-priority
+* https://spec.oneapi.com/level-zero/latest/core/api.html#ze-command-queue-priority-t
+
+New parallel submission uAPI
+============================
+The existing bonding uAPI is completely broken with GuC submission because
+whether a submission is a single context submit or parallel submit isn't known
+until execbuf time activated via the I915_SUBMIT_FENCE. To submit multiple
+contexts in parallel with the GuC the context must be explicitly registered with
+N contexts and all N contexts must be submitted in a single command to the GuC.
+The GuC interfaces do not support dynamically changing between N contexts as the
+bonding uAPI does. Hence the need for a new parallel submission interface. Also
+the legacy bonding uAPI is quite confusing and not intuitive at all. Furthermore
+I915_SUBMIT_FENCE is by design a future fence, so not really something we should
+continue to support.
+
+The new parallel submission uAPI consists of 3 parts:
+
+* Export engines logical mapping
+* A 'set_parallel' extension to configure contexts for parallel
+ submission
+* Extend execbuf2 IOCTL to support submitting N BBs in a single IOCTL
+
+Export engines logical mapping
+------------------------------
+Certain use cases require BBs to be placed on engine instances in logical order
+(e.g. split-frame on gen11+). The logical mapping of engine instances can change
+based on fusing. Rather than making UMDs be aware of fusing, simply expose the
+logical mapping with the existing query engine info IOCTL. Also the GuC
+submission interface currently only supports submitting multiple contexts to
+engines in logical order which is a new requirement compared to execlists.
+Lastly, all current platforms have at most 2 engine instances and the logical
+order is the same as uAPI order. This will change on platforms with more than 2
+engine instances.
+
+A single bit will be added to drm_i915_engine_info.flags indicating that the
+logical instance has been returned and a new field,
+drm_i915_engine_info.logical_instance, returns the logical instance.
+
+A 'set_parallel' extension to configure contexts for parallel submission
+------------------------------------------------------------------------
+The 'set_parallel' extension configures a slot for parallel submission of N BBs.
+It is a setup step that must be called before using any of the contexts. See
+I915_CONTEXT_ENGINES_EXT_LOAD_BALANCE or I915_CONTEXT_ENGINES_EXT_BOND for
+similar existing examples. Once a slot is configured for parallel submission the
+execbuf2 IOCTL can be called submitting N BBs in a single IOCTL. Initially only
+supports GuC submission. Execlists supports can be added later if needed.
+
+Add I915_CONTEXT_ENGINES_EXT_PARALLEL_SUBMIT and
+drm_i915_context_engines_parallel_submit to the uAPI to implement this
+extension.
+
+.. c:namespace-push:: rfc
+
+.. kernel-doc:: include/uapi/drm/i915_drm.h
+ :functions: i915_context_engines_parallel_submit
+
+.. c:namespace-pop::
+
+Extend execbuf2 IOCTL to support submitting N BBs in a single IOCTL
+-------------------------------------------------------------------
+Contexts that have been configured with the 'set_parallel' extension can only
+submit N BBs in a single execbuf2 IOCTL. The BBs are either the last N objects
+in the drm_i915_gem_exec_object2 list or the first N if I915_EXEC_BATCH_FIRST is
+set. The number of BBs is implicit based on the slot submitted and how it has
+been configured by 'set_parallel' or other extensions. No uAPI changes are
+required to the execbuf2 IOCTL.
diff --git a/Documentation/gpu/rfc/i915_small_bar.h b/Documentation/gpu/rfc/i915_small_bar.h
new file mode 100644
index 000000000..6003c81d5
--- /dev/null
+++ b/Documentation/gpu/rfc/i915_small_bar.h
@@ -0,0 +1,189 @@
+/**
+ * struct __drm_i915_memory_region_info - Describes one region as known to the
+ * driver.
+ *
+ * Note this is using both struct drm_i915_query_item and struct drm_i915_query.
+ * For this new query we are adding the new query id DRM_I915_QUERY_MEMORY_REGIONS
+ * at &drm_i915_query_item.query_id.
+ */
+struct __drm_i915_memory_region_info {
+ /** @region: The class:instance pair encoding */
+ struct drm_i915_gem_memory_class_instance region;
+
+ /** @rsvd0: MBZ */
+ __u32 rsvd0;
+
+ /**
+ * @probed_size: Memory probed by the driver
+ *
+ * Note that it should not be possible to ever encounter a zero value
+ * here, also note that no current region type will ever return -1 here.
+ * Although for future region types, this might be a possibility. The
+ * same applies to the other size fields.
+ */
+ __u64 probed_size;
+
+ /**
+ * @unallocated_size: Estimate of memory remaining
+ *
+ * Requires CAP_PERFMON or CAP_SYS_ADMIN to get reliable accounting.
+ * Without this (or if this is an older kernel) the value here will
+ * always equal the @probed_size. Note this is only currently tracked
+ * for I915_MEMORY_CLASS_DEVICE regions (for other types the value here
+ * will always equal the @probed_size).
+ */
+ __u64 unallocated_size;
+
+ union {
+ /** @rsvd1: MBZ */
+ __u64 rsvd1[8];
+ struct {
+ /**
+ * @probed_cpu_visible_size: Memory probed by the driver
+ * that is CPU accessible.
+ *
+ * This will be always be <= @probed_size, and the
+ * remainder (if there is any) will not be CPU
+ * accessible.
+ *
+ * On systems without small BAR, the @probed_size will
+ * always equal the @probed_cpu_visible_size, since all
+ * of it will be CPU accessible.
+ *
+ * Note this is only tracked for
+ * I915_MEMORY_CLASS_DEVICE regions (for other types the
+ * value here will always equal the @probed_size).
+ *
+ * Note that if the value returned here is zero, then
+ * this must be an old kernel which lacks the relevant
+ * small-bar uAPI support (including
+ * I915_GEM_CREATE_EXT_FLAG_NEEDS_CPU_ACCESS), but on
+ * such systems we should never actually end up with a
+ * small BAR configuration, assuming we are able to load
+ * the kernel module. Hence it should be safe to treat
+ * this the same as when @probed_cpu_visible_size ==
+ * @probed_size.
+ */
+ __u64 probed_cpu_visible_size;
+
+ /**
+ * @unallocated_cpu_visible_size: Estimate of CPU
+ * visible memory remaining
+ *
+ * Note this is only tracked for
+ * I915_MEMORY_CLASS_DEVICE regions (for other types the
+ * value here will always equal the
+ * @probed_cpu_visible_size).
+ *
+ * Requires CAP_PERFMON or CAP_SYS_ADMIN to get reliable
+ * accounting. Without this the value here will always
+ * equal the @probed_cpu_visible_size. Note this is only
+ * currently tracked for I915_MEMORY_CLASS_DEVICE
+ * regions (for other types the value here will also
+ * always equal the @probed_cpu_visible_size).
+ *
+ * If this is an older kernel the value here will be
+ * zero, see also @probed_cpu_visible_size.
+ */
+ __u64 unallocated_cpu_visible_size;
+ };
+ };
+};
+
+/**
+ * struct __drm_i915_gem_create_ext - Existing gem_create behaviour, with added
+ * extension support using struct i915_user_extension.
+ *
+ * Note that new buffer flags should be added here, at least for the stuff that
+ * is immutable. Previously we would have two ioctls, one to create the object
+ * with gem_create, and another to apply various parameters, however this
+ * creates some ambiguity for the params which are considered immutable. Also in
+ * general we're phasing out the various SET/GET ioctls.
+ */
+struct __drm_i915_gem_create_ext {
+ /**
+ * @size: Requested size for the object.
+ *
+ * The (page-aligned) allocated size for the object will be returned.
+ *
+ * Note that for some devices we have might have further minimum
+ * page-size restrictions (larger than 4K), like for device local-memory.
+ * However in general the final size here should always reflect any
+ * rounding up, if for example using the I915_GEM_CREATE_EXT_MEMORY_REGIONS
+ * extension to place the object in device local-memory. The kernel will
+ * always select the largest minimum page-size for the set of possible
+ * placements as the value to use when rounding up the @size.
+ */
+ __u64 size;
+
+ /**
+ * @handle: Returned handle for the object.
+ *
+ * Object handles are nonzero.
+ */
+ __u32 handle;
+
+ /**
+ * @flags: Optional flags.
+ *
+ * Supported values:
+ *
+ * I915_GEM_CREATE_EXT_FLAG_NEEDS_CPU_ACCESS - Signal to the kernel that
+ * the object will need to be accessed via the CPU.
+ *
+ * Only valid when placing objects in I915_MEMORY_CLASS_DEVICE, and only
+ * strictly required on configurations where some subset of the device
+ * memory is directly visible/mappable through the CPU (which we also
+ * call small BAR), like on some DG2+ systems. Note that this is quite
+ * undesirable, but due to various factors like the client CPU, BIOS etc
+ * it's something we can expect to see in the wild. See
+ * &__drm_i915_memory_region_info.probed_cpu_visible_size for how to
+ * determine if this system applies.
+ *
+ * Note that one of the placements MUST be I915_MEMORY_CLASS_SYSTEM, to
+ * ensure the kernel can always spill the allocation to system memory,
+ * if the object can't be allocated in the mappable part of
+ * I915_MEMORY_CLASS_DEVICE.
+ *
+ * Also note that since the kernel only supports flat-CCS on objects
+ * that can *only* be placed in I915_MEMORY_CLASS_DEVICE, we therefore
+ * don't support I915_GEM_CREATE_EXT_FLAG_NEEDS_CPU_ACCESS together with
+ * flat-CCS.
+ *
+ * Without this hint, the kernel will assume that non-mappable
+ * I915_MEMORY_CLASS_DEVICE is preferred for this object. Note that the
+ * kernel can still migrate the object to the mappable part, as a last
+ * resort, if userspace ever CPU faults this object, but this might be
+ * expensive, and so ideally should be avoided.
+ *
+ * On older kernels which lack the relevant small-bar uAPI support (see
+ * also &__drm_i915_memory_region_info.probed_cpu_visible_size),
+ * usage of the flag will result in an error, but it should NEVER be
+ * possible to end up with a small BAR configuration, assuming we can
+ * also successfully load the i915 kernel module. In such cases the
+ * entire I915_MEMORY_CLASS_DEVICE region will be CPU accessible, and as
+ * such there are zero restrictions on where the object can be placed.
+ */
+#define I915_GEM_CREATE_EXT_FLAG_NEEDS_CPU_ACCESS (1 << 0)
+ __u32 flags;
+
+ /**
+ * @extensions: The chain of extensions to apply to this object.
+ *
+ * This will be useful in the future when we need to support several
+ * different extensions, and we need to apply more than one when
+ * creating the object. See struct i915_user_extension.
+ *
+ * If we don't supply any extensions then we get the same old gem_create
+ * behaviour.
+ *
+ * For I915_GEM_CREATE_EXT_MEMORY_REGIONS usage see
+ * struct drm_i915_gem_create_ext_memory_regions.
+ *
+ * For I915_GEM_CREATE_EXT_PROTECTED_CONTENT usage see
+ * struct drm_i915_gem_create_ext_protected_content.
+ */
+#define I915_GEM_CREATE_EXT_MEMORY_REGIONS 0
+#define I915_GEM_CREATE_EXT_PROTECTED_CONTENT 1
+ __u64 extensions;
+};
diff --git a/Documentation/gpu/rfc/i915_small_bar.rst b/Documentation/gpu/rfc/i915_small_bar.rst
new file mode 100644
index 000000000..d6c03ce3b
--- /dev/null
+++ b/Documentation/gpu/rfc/i915_small_bar.rst
@@ -0,0 +1,47 @@
+==========================
+I915 Small BAR RFC Section
+==========================
+Starting from DG2 we will have resizable BAR support for device local-memory(i.e
+I915_MEMORY_CLASS_DEVICE), but in some cases the final BAR size might still be
+smaller than the total probed_size. In such cases, only some subset of
+I915_MEMORY_CLASS_DEVICE will be CPU accessible(for example the first 256M),
+while the remainder is only accessible via the GPU.
+
+I915_GEM_CREATE_EXT_FLAG_NEEDS_CPU_ACCESS flag
+----------------------------------------------
+New gem_create_ext flag to tell the kernel that a BO will require CPU access.
+This becomes important when placing an object in I915_MEMORY_CLASS_DEVICE, where
+underneath the device has a small BAR, meaning only some portion of it is CPU
+accessible. Without this flag the kernel will assume that CPU access is not
+required, and prioritize using the non-CPU visible portion of
+I915_MEMORY_CLASS_DEVICE.
+
+.. kernel-doc:: Documentation/gpu/rfc/i915_small_bar.h
+ :functions: __drm_i915_gem_create_ext
+
+probed_cpu_visible_size attribute
+---------------------------------
+New struct__drm_i915_memory_region attribute which returns the total size of the
+CPU accessible portion, for the particular region. This should only be
+applicable for I915_MEMORY_CLASS_DEVICE. We also report the
+unallocated_cpu_visible_size, alongside the unallocated_size.
+
+Vulkan will need this as part of creating a separate VkMemoryHeap with the
+VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT set, to represent the CPU visible portion,
+where the total size of the heap needs to be known. It also wants to be able to
+give a rough estimate of how memory can potentially be allocated.
+
+.. kernel-doc:: Documentation/gpu/rfc/i915_small_bar.h
+ :functions: __drm_i915_memory_region_info
+
+Error Capture restrictions
+--------------------------
+With error capture we have two new restrictions:
+
+ 1) Error capture is best effort on small BAR systems; if the pages are not
+ CPU accessible, at the time of capture, then the kernel is free to skip
+ trying to capture them.
+
+ 2) On discrete and newer integrated platforms we now reject error capture
+ on recoverable contexts. In the future the kernel may want to blit during
+ error capture, when for example something is not currently CPU accessible.
diff --git a/Documentation/gpu/rfc/i915_vm_bind.h b/Documentation/gpu/rfc/i915_vm_bind.h
new file mode 100644
index 000000000..bc26dc126
--- /dev/null
+++ b/Documentation/gpu/rfc/i915_vm_bind.h
@@ -0,0 +1,290 @@
+/* SPDX-License-Identifier: MIT */
+/*
+ * Copyright © 2022 Intel Corporation
+ */
+
+/**
+ * DOC: I915_PARAM_VM_BIND_VERSION
+ *
+ * VM_BIND feature version supported.
+ * See typedef drm_i915_getparam_t param.
+ *
+ * Specifies the VM_BIND feature version supported.
+ * The following versions of VM_BIND have been defined:
+ *
+ * 0: No VM_BIND support.
+ *
+ * 1: In VM_UNBIND calls, the UMD must specify the exact mappings created
+ * previously with VM_BIND, the ioctl will not support unbinding multiple
+ * mappings or splitting them. Similarly, VM_BIND calls will not replace
+ * any existing mappings.
+ *
+ * 2: The restrictions on unbinding partial or multiple mappings is
+ * lifted, Similarly, binding will replace any mappings in the given range.
+ *
+ * See struct drm_i915_gem_vm_bind and struct drm_i915_gem_vm_unbind.
+ */
+#define I915_PARAM_VM_BIND_VERSION 57
+
+/**
+ * DOC: I915_VM_CREATE_FLAGS_USE_VM_BIND
+ *
+ * Flag to opt-in for VM_BIND mode of binding during VM creation.
+ * See struct drm_i915_gem_vm_control flags.
+ *
+ * The older execbuf2 ioctl will not support VM_BIND mode of operation.
+ * For VM_BIND mode, we have new execbuf3 ioctl which will not accept any
+ * execlist (See struct drm_i915_gem_execbuffer3 for more details).
+ */
+#define I915_VM_CREATE_FLAGS_USE_VM_BIND (1 << 0)
+
+/* VM_BIND related ioctls */
+#define DRM_I915_GEM_VM_BIND 0x3d
+#define DRM_I915_GEM_VM_UNBIND 0x3e
+#define DRM_I915_GEM_EXECBUFFER3 0x3f
+
+#define DRM_IOCTL_I915_GEM_VM_BIND DRM_IOWR(DRM_COMMAND_BASE + DRM_I915_GEM_VM_BIND, struct drm_i915_gem_vm_bind)
+#define DRM_IOCTL_I915_GEM_VM_UNBIND DRM_IOWR(DRM_COMMAND_BASE + DRM_I915_GEM_VM_UNBIND, struct drm_i915_gem_vm_bind)
+#define DRM_IOCTL_I915_GEM_EXECBUFFER3 DRM_IOWR(DRM_COMMAND_BASE + DRM_I915_GEM_EXECBUFFER3, struct drm_i915_gem_execbuffer3)
+
+/**
+ * struct drm_i915_gem_timeline_fence - An input or output timeline fence.
+ *
+ * The operation will wait for input fence to signal.
+ *
+ * The returned output fence will be signaled after the completion of the
+ * operation.
+ */
+struct drm_i915_gem_timeline_fence {
+ /** @handle: User's handle for a drm_syncobj to wait on or signal. */
+ __u32 handle;
+
+ /**
+ * @flags: Supported flags are:
+ *
+ * I915_TIMELINE_FENCE_WAIT:
+ * Wait for the input fence before the operation.
+ *
+ * I915_TIMELINE_FENCE_SIGNAL:
+ * Return operation completion fence as output.
+ */
+ __u32 flags;
+#define I915_TIMELINE_FENCE_WAIT (1 << 0)
+#define I915_TIMELINE_FENCE_SIGNAL (1 << 1)
+#define __I915_TIMELINE_FENCE_UNKNOWN_FLAGS (-(I915_TIMELINE_FENCE_SIGNAL << 1))
+
+ /**
+ * @value: A point in the timeline.
+ * Value must be 0 for a binary drm_syncobj. A Value of 0 for a
+ * timeline drm_syncobj is invalid as it turns a drm_syncobj into a
+ * binary one.
+ */
+ __u64 value;
+};
+
+/**
+ * struct drm_i915_gem_vm_bind - VA to object mapping to bind.
+ *
+ * This structure is passed to VM_BIND ioctl and specifies the mapping of GPU
+ * virtual address (VA) range to the section of an object that should be bound
+ * in the device page table of the specified address space (VM).
+ * The VA range specified must be unique (ie., not currently bound) and can
+ * be mapped to whole object or a section of the object (partial binding).
+ * Multiple VA mappings can be created to the same section of the object
+ * (aliasing).
+ *
+ * The @start, @offset and @length must be 4K page aligned. However the DG2 has
+ * 64K page size for device local memory and has compact page table. On that
+ * platform, for binding device local-memory objects, the @start, @offset and
+ * @length must be 64K aligned. Also, UMDs should not mix the local memory 64K
+ * page and the system memory 4K page bindings in the same 2M range.
+ *
+ * Error code -EINVAL will be returned if @start, @offset and @length are not
+ * properly aligned. In version 1 (See I915_PARAM_VM_BIND_VERSION), error code
+ * -ENOSPC will be returned if the VA range specified can't be reserved.
+ *
+ * VM_BIND/UNBIND ioctl calls executed on different CPU threads concurrently
+ * are not ordered. Furthermore, parts of the VM_BIND operation can be done
+ * asynchronously, if valid @fence is specified.
+ */
+struct drm_i915_gem_vm_bind {
+ /** @vm_id: VM (address space) id to bind */
+ __u32 vm_id;
+
+ /** @handle: Object handle */
+ __u32 handle;
+
+ /** @start: Virtual Address start to bind */
+ __u64 start;
+
+ /** @offset: Offset in object to bind */
+ __u64 offset;
+
+ /** @length: Length of mapping to bind */
+ __u64 length;
+
+ /**
+ * @flags: Supported flags are:
+ *
+ * I915_GEM_VM_BIND_CAPTURE:
+ * Capture this mapping in the dump upon GPU error.
+ *
+ * Note that @fence carries its own flags.
+ */
+ __u64 flags;
+#define I915_GEM_VM_BIND_CAPTURE (1 << 0)
+
+ /**
+ * @fence: Timeline fence for bind completion signaling.
+ *
+ * Timeline fence is of format struct drm_i915_gem_timeline_fence.
+ *
+ * It is an out fence, hence using I915_TIMELINE_FENCE_WAIT flag
+ * is invalid, and an error will be returned.
+ *
+ * If I915_TIMELINE_FENCE_SIGNAL flag is not set, then out fence
+ * is not requested and binding is completed synchronously.
+ */
+ struct drm_i915_gem_timeline_fence fence;
+
+ /**
+ * @extensions: Zero-terminated chain of extensions.
+ *
+ * For future extensions. See struct i915_user_extension.
+ */
+ __u64 extensions;
+};
+
+/**
+ * struct drm_i915_gem_vm_unbind - VA to object mapping to unbind.
+ *
+ * This structure is passed to VM_UNBIND ioctl and specifies the GPU virtual
+ * address (VA) range that should be unbound from the device page table of the
+ * specified address space (VM). VM_UNBIND will force unbind the specified
+ * range from device page table without waiting for any GPU job to complete.
+ * It is UMDs responsibility to ensure the mapping is no longer in use before
+ * calling VM_UNBIND.
+ *
+ * If the specified mapping is not found, the ioctl will simply return without
+ * any error.
+ *
+ * VM_BIND/UNBIND ioctl calls executed on different CPU threads concurrently
+ * are not ordered. Furthermore, parts of the VM_UNBIND operation can be done
+ * asynchronously, if valid @fence is specified.
+ */
+struct drm_i915_gem_vm_unbind {
+ /** @vm_id: VM (address space) id to bind */
+ __u32 vm_id;
+
+ /** @rsvd: Reserved, MBZ */
+ __u32 rsvd;
+
+ /** @start: Virtual Address start to unbind */
+ __u64 start;
+
+ /** @length: Length of mapping to unbind */
+ __u64 length;
+
+ /**
+ * @flags: Currently reserved, MBZ.
+ *
+ * Note that @fence carries its own flags.
+ */
+ __u64 flags;
+
+ /**
+ * @fence: Timeline fence for unbind completion signaling.
+ *
+ * Timeline fence is of format struct drm_i915_gem_timeline_fence.
+ *
+ * It is an out fence, hence using I915_TIMELINE_FENCE_WAIT flag
+ * is invalid, and an error will be returned.
+ *
+ * If I915_TIMELINE_FENCE_SIGNAL flag is not set, then out fence
+ * is not requested and unbinding is completed synchronously.
+ */
+ struct drm_i915_gem_timeline_fence fence;
+
+ /**
+ * @extensions: Zero-terminated chain of extensions.
+ *
+ * For future extensions. See struct i915_user_extension.
+ */
+ __u64 extensions;
+};
+
+/**
+ * struct drm_i915_gem_execbuffer3 - Structure for DRM_I915_GEM_EXECBUFFER3
+ * ioctl.
+ *
+ * DRM_I915_GEM_EXECBUFFER3 ioctl only works in VM_BIND mode and VM_BIND mode
+ * only works with this ioctl for submission.
+ * See I915_VM_CREATE_FLAGS_USE_VM_BIND.
+ */
+struct drm_i915_gem_execbuffer3 {
+ /**
+ * @ctx_id: Context id
+ *
+ * Only contexts with user engine map are allowed.
+ */
+ __u32 ctx_id;
+
+ /**
+ * @engine_idx: Engine index
+ *
+ * An index in the user engine map of the context specified by @ctx_id.
+ */
+ __u32 engine_idx;
+
+ /**
+ * @batch_address: Batch gpu virtual address/es.
+ *
+ * For normal submission, it is the gpu virtual address of the batch
+ * buffer. For parallel submission, it is a pointer to an array of
+ * batch buffer gpu virtual addresses with array size equal to the
+ * number of (parallel) engines involved in that submission (See
+ * struct i915_context_engines_parallel_submit).
+ */
+ __u64 batch_address;
+
+ /** @flags: Currently reserved, MBZ */
+ __u64 flags;
+
+ /** @rsvd1: Reserved, MBZ */
+ __u32 rsvd1;
+
+ /** @fence_count: Number of fences in @timeline_fences array. */
+ __u32 fence_count;
+
+ /**
+ * @timeline_fences: Pointer to an array of timeline fences.
+ *
+ * Timeline fences are of format struct drm_i915_gem_timeline_fence.
+ */
+ __u64 timeline_fences;
+
+ /** @rsvd2: Reserved, MBZ */
+ __u64 rsvd2;
+
+ /**
+ * @extensions: Zero-terminated chain of extensions.
+ *
+ * For future extensions. See struct i915_user_extension.
+ */
+ __u64 extensions;
+};
+
+/**
+ * struct drm_i915_gem_create_ext_vm_private - Extension to make the object
+ * private to the specified VM.
+ *
+ * See struct drm_i915_gem_create_ext.
+ */
+struct drm_i915_gem_create_ext_vm_private {
+#define I915_GEM_CREATE_EXT_VM_PRIVATE 2
+ /** @base: Extension link. See struct i915_user_extension. */
+ struct i915_user_extension base;
+
+ /** @vm_id: Id of the VM to which the object is private */
+ __u32 vm_id;
+};
diff --git a/Documentation/gpu/rfc/i915_vm_bind.rst b/Documentation/gpu/rfc/i915_vm_bind.rst
new file mode 100644
index 000000000..0b3b525ac
--- /dev/null
+++ b/Documentation/gpu/rfc/i915_vm_bind.rst
@@ -0,0 +1,245 @@
+==========================================
+I915 VM_BIND feature design and use cases
+==========================================
+
+VM_BIND feature
+================
+DRM_I915_GEM_VM_BIND/UNBIND ioctls allows UMD to bind/unbind GEM buffer
+objects (BOs) or sections of a BOs at specified GPU virtual addresses on a
+specified address space (VM). These mappings (also referred to as persistent
+mappings) will be persistent across multiple GPU submissions (execbuf calls)
+issued by the UMD, without user having to provide a list of all required
+mappings during each submission (as required by older execbuf mode).
+
+The VM_BIND/UNBIND calls allow UMDs to request a timeline out fence for
+signaling the completion of bind/unbind operation.
+
+VM_BIND feature is advertised to user via I915_PARAM_VM_BIND_VERSION.
+User has to opt-in for VM_BIND mode of binding for an address space (VM)
+during VM creation time via I915_VM_CREATE_FLAGS_USE_VM_BIND extension.
+
+VM_BIND/UNBIND ioctl calls executed on different CPU threads concurrently are
+not ordered. Furthermore, parts of the VM_BIND/UNBIND operations can be done
+asynchronously, when valid out fence is specified.
+
+VM_BIND features include:
+
+* Multiple Virtual Address (VA) mappings can map to the same physical pages
+ of an object (aliasing).
+* VA mapping can map to a partial section of the BO (partial binding).
+* Support capture of persistent mappings in the dump upon GPU error.
+* Support for userptr gem objects (no special uapi is required for this).
+
+TLB flush consideration
+------------------------
+The i915 driver flushes the TLB for each submission and when an object's
+pages are released. The VM_BIND/UNBIND operation will not do any additional
+TLB flush. Any VM_BIND mapping added will be in the working set for subsequent
+submissions on that VM and will not be in the working set for currently running
+batches (which would require additional TLB flushes, which is not supported).
+
+Execbuf ioctl in VM_BIND mode
+-------------------------------
+A VM in VM_BIND mode will not support older execbuf mode of binding.
+The execbuf ioctl handling in VM_BIND mode differs significantly from the
+older execbuf2 ioctl (See struct drm_i915_gem_execbuffer2).
+Hence, a new execbuf3 ioctl has been added to support VM_BIND mode. (See
+struct drm_i915_gem_execbuffer3). The execbuf3 ioctl will not accept any
+execlist. Hence, no support for implicit sync. It is expected that the below
+work will be able to support requirements of object dependency setting in all
+use cases:
+
+"dma-buf: Add an API for exporting sync files"
+(https://lwn.net/Articles/859290/)
+
+The new execbuf3 ioctl only works in VM_BIND mode and the VM_BIND mode only
+works with execbuf3 ioctl for submission. All BOs mapped on that VM (through
+VM_BIND call) at the time of execbuf3 call are deemed required for that
+submission.
+
+The execbuf3 ioctl directly specifies the batch addresses instead of as
+object handles as in execbuf2 ioctl. The execbuf3 ioctl will also not
+support many of the older features like in/out/submit fences, fence array,
+default gem context and many more (See struct drm_i915_gem_execbuffer3).
+
+In VM_BIND mode, VA allocation is completely managed by the user instead of
+the i915 driver. Hence all VA assignment, eviction are not applicable in
+VM_BIND mode. Also, for determining object activeness, VM_BIND mode will not
+be using the i915_vma active reference tracking. It will instead use dma-resv
+object for that (See `VM_BIND dma_resv usage`_).
+
+So, a lot of existing code supporting execbuf2 ioctl, like relocations, VA
+evictions, vma lookup table, implicit sync, vma active reference tracking etc.,
+are not applicable for execbuf3 ioctl. Hence, all execbuf3 specific handling
+should be in a separate file and only functionalities common to these ioctls
+can be the shared code where possible.
+
+VM_PRIVATE objects
+-------------------
+By default, BOs can be mapped on multiple VMs and can also be dma-buf
+exported. Hence these BOs are referred to as Shared BOs.
+During each execbuf submission, the request fence must be added to the
+dma-resv fence list of all shared BOs mapped on the VM.
+
+VM_BIND feature introduces an optimization where user can create BO which
+is private to a specified VM via I915_GEM_CREATE_EXT_VM_PRIVATE flag during
+BO creation. Unlike Shared BOs, these VM private BOs can only be mapped on
+the VM they are private to and can't be dma-buf exported.
+All private BOs of a VM share the dma-resv object. Hence during each execbuf
+submission, they need only one dma-resv fence list updated. Thus, the fast
+path (where required mappings are already bound) submission latency is O(1)
+w.r.t the number of VM private BOs.
+
+VM_BIND locking hierarchy
+-------------------------
+The locking design here supports the older (execlist based) execbuf mode, the
+newer VM_BIND mode, the VM_BIND mode with GPU page faults and possible future
+system allocator support (See `Shared Virtual Memory (SVM) support`_).
+The older execbuf mode and the newer VM_BIND mode without page faults manages
+residency of backing storage using dma_fence. The VM_BIND mode with page faults
+and the system allocator support do not use any dma_fence at all.
+
+VM_BIND locking order is as below.
+
+1) Lock-A: A vm_bind mutex will protect vm_bind lists. This lock is taken in
+ vm_bind/vm_unbind ioctl calls, in the execbuf path and while releasing the
+ mapping.
+
+ In future, when GPU page faults are supported, we can potentially use a
+ rwsem instead, so that multiple page fault handlers can take the read side
+ lock to lookup the mapping and hence can run in parallel.
+ The older execbuf mode of binding do not need this lock.
+
+2) Lock-B: The object's dma-resv lock will protect i915_vma state and needs to
+ be held while binding/unbinding a vma in the async worker and while updating
+ dma-resv fence list of an object. Note that private BOs of a VM will all
+ share a dma-resv object.
+
+ The future system allocator support will use the HMM prescribed locking
+ instead.
+
+3) Lock-C: Spinlock/s to protect some of the VM's lists like the list of
+ invalidated vmas (due to eviction and userptr invalidation) etc.
+
+When GPU page faults are supported, the execbuf path do not take any of these
+locks. There we will simply smash the new batch buffer address into the ring and
+then tell the scheduler run that. The lock taking only happens from the page
+fault handler, where we take lock-A in read mode, whichever lock-B we need to
+find the backing storage (dma_resv lock for gem objects, and hmm/core mm for
+system allocator) and some additional locks (lock-D) for taking care of page
+table races. Page fault mode should not need to ever manipulate the vm lists,
+so won't ever need lock-C.
+
+VM_BIND LRU handling
+---------------------
+We need to ensure VM_BIND mapped objects are properly LRU tagged to avoid
+performance degradation. We will also need support for bulk LRU movement of
+VM_BIND objects to avoid additional latencies in execbuf path.
+
+The page table pages are similar to VM_BIND mapped objects (See
+`Evictable page table allocations`_) and are maintained per VM and needs to
+be pinned in memory when VM is made active (ie., upon an execbuf call with
+that VM). So, bulk LRU movement of page table pages is also needed.
+
+VM_BIND dma_resv usage
+-----------------------
+Fences needs to be added to all VM_BIND mapped objects. During each execbuf
+submission, they are added with DMA_RESV_USAGE_BOOKKEEP usage to prevent
+over sync (See enum dma_resv_usage). One can override it with either
+DMA_RESV_USAGE_READ or DMA_RESV_USAGE_WRITE usage during explicit object
+dependency setting.
+
+Note that DRM_I915_GEM_WAIT and DRM_I915_GEM_BUSY ioctls do not check for
+DMA_RESV_USAGE_BOOKKEEP usage and hence should not be used for end of batch
+check. Instead, the execbuf3 out fence should be used for end of batch check
+(See struct drm_i915_gem_execbuffer3).
+
+Also, in VM_BIND mode, use dma-resv apis for determining object activeness
+(See dma_resv_test_signaled() and dma_resv_wait_timeout()) and do not use the
+older i915_vma active reference tracking which is deprecated. This should be
+easier to get it working with the current TTM backend.
+
+Mesa use case
+--------------
+VM_BIND can potentially reduce the CPU overhead in Mesa (both Vulkan and Iris),
+hence improving performance of CPU-bound applications. It also allows us to
+implement Vulkan's Sparse Resources. With increasing GPU hardware performance,
+reducing CPU overhead becomes more impactful.
+
+
+Other VM_BIND use cases
+========================
+
+Long running Compute contexts
+------------------------------
+Usage of dma-fence expects that they complete in reasonable amount of time.
+Compute on the other hand can be long running. Hence it is appropriate for
+compute to use user/memory fence (See `User/Memory Fence`_) and dma-fence usage
+must be limited to in-kernel consumption only.
+
+Where GPU page faults are not available, kernel driver upon buffer invalidation
+will initiate a suspend (preemption) of long running context, finish the
+invalidation, revalidate the BO and then resume the compute context. This is
+done by having a per-context preempt fence which is enabled when someone tries
+to wait on it and triggers the context preemption.
+
+User/Memory Fence
+~~~~~~~~~~~~~~~~~~
+User/Memory fence is a <address, value> pair. To signal the user fence, the
+specified value will be written at the specified virtual address and wakeup the
+waiting process. User fence can be signaled either by the GPU or kernel async
+worker (like upon bind completion). User can wait on a user fence with a new
+user fence wait ioctl.
+
+Here is some prior work on this:
+https://patchwork.freedesktop.org/patch/349417/
+
+Low Latency Submission
+~~~~~~~~~~~~~~~~~~~~~~~
+Allows compute UMD to directly submit GPU jobs instead of through execbuf
+ioctl. This is made possible by VM_BIND is not being synchronized against
+execbuf. VM_BIND allows bind/unbind of mappings required for the directly
+submitted jobs.
+
+Debugger
+---------
+With debug event interface user space process (debugger) is able to keep track
+of and act upon resources created by another process (debugged) and attached
+to GPU via vm_bind interface.
+
+GPU page faults
+----------------
+GPU page faults when supported (in future), will only be supported in the
+VM_BIND mode. While both the older execbuf mode and the newer VM_BIND mode of
+binding will require using dma-fence to ensure residency, the GPU page faults
+mode when supported, will not use any dma-fence as residency is purely managed
+by installing and removing/invalidating page table entries.
+
+Page level hints settings
+--------------------------
+VM_BIND allows any hints setting per mapping instead of per BO. Possible hints
+include placement and atomicity. Sub-BO level placement hint will be even more
+relevant with upcoming GPU on-demand page fault support.
+
+Page level Cache/CLOS settings
+-------------------------------
+VM_BIND allows cache/CLOS settings per mapping instead of per BO.
+
+Evictable page table allocations
+---------------------------------
+Make pagetable allocations evictable and manage them similar to VM_BIND
+mapped objects. Page table pages are similar to persistent mappings of a
+VM (difference here are that the page table pages will not have an i915_vma
+structure and after swapping pages back in, parent page link needs to be
+updated).
+
+Shared Virtual Memory (SVM) support
+------------------------------------
+VM_BIND interface can be used to map system memory directly (without gem BO
+abstraction) using the HMM interface. SVM is only supported with GPU page
+faults enabled.
+
+VM_BIND UAPI
+=============
+
+.. kernel-doc:: Documentation/gpu/rfc/i915_vm_bind.h
diff --git a/Documentation/gpu/rfc/index.rst b/Documentation/gpu/rfc/index.rst
new file mode 100644
index 000000000..26a7ebe6f
--- /dev/null
+++ b/Documentation/gpu/rfc/index.rst
@@ -0,0 +1,26 @@
+===============
+GPU RFC Section
+===============
+
+For complex work, especially new uapi, it is often good to nail the high level
+design issues before getting lost in the code details. This section is meant to
+host such documentation:
+
+* Each RFC should be a section in this file, explaining the goal and main design
+ considerations. Especially for uapi make sure you Cc: all relevant project
+ mailing lists and involved people outside of dri-devel.
+
+* For uapi structures add a file to this directory with and then pull the
+ kerneldoc in like with real uapi headers.
+
+* Once the code has landed move all the documentation to the right places in
+ the main core, helper or driver sections.
+
+.. toctree::
+
+ gpusvm
+ i915_gem_lmem
+ i915_scheduler
+ i915_small_bar
+ i915_vm_bind
+ color_pipeline