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* SPDX-License-Identifier: MIT
* Copyright © 2019 Intel Corporation
#ifndef __I915_GEM_CONTEXT_TYPES_H__
#define __I915_GEM_CONTEXT_TYPES_H__
#include <linux/atomic.h>
#include <linux/list.h>
#include <linux/llist.h>
#include <linux/kref.h>
#include <linux/mutex.h>
#include <linux/radix-tree.h>
#include <linux/rbtree.h>
#include <linux/rcupdate.h>
#include <linux/types.h>
#include "gt/intel_context_types.h"
#include "i915_scheduler.h"
#include "i915_sw_fence.h"
struct pid;
struct drm_i915_private;
struct drm_i915_file_private;
struct i915_address_space;
struct intel_timeline;
struct intel_ring;
* struct i915_gem_engines - A set of engines
struct i915_gem_engines {
union {
/** @link: Link in i915_gem_context::stale::engines */
struct list_head link;
/** @rcu: RCU to use when freeing */
struct rcu_head rcu;
/** @fence: Fence used for delayed destruction of engines */
struct i915_sw_fence fence;
/** @ctx: i915_gem_context backpointer */
struct i915_gem_context *ctx;
/** @num_engines: Number of engines in this set */
unsigned int num_engines;
/** @engines: Array of engines */
struct intel_context *engines[];
* struct i915_gem_engines_iter - Iterator for an i915_gem_engines set
struct i915_gem_engines_iter {
/** @idx: Index into i915_gem_engines::engines */
unsigned int idx;
/** @engines: Engine set being iterated */
const struct i915_gem_engines *engines;
* enum i915_gem_engine_type - Describes the type of an i915_gem_proto_engine
enum i915_gem_engine_type {
/** @I915_GEM_ENGINE_TYPE_INVALID: An invalid engine */
/** @I915_GEM_ENGINE_TYPE_PHYSICAL: A single physical engine */
/** @I915_GEM_ENGINE_TYPE_BALANCED: A load-balanced engine set */
/** @I915_GEM_ENGINE_TYPE_PARALLEL: A parallel engine set */
* struct i915_gem_proto_engine - prototype engine
* This struct describes an engine that a context may contain. Engines
* have four types:
* - I915_GEM_ENGINE_TYPE_INVALID: Invalid engines can be created but they
* show up as a NULL in i915_gem_engines::engines[i] and any attempt to
* use them by the user results in -EINVAL. They are also useful during
* proto-context construction because the client may create invalid
* engines and then set them up later as virtual engines.
* - I915_GEM_ENGINE_TYPE_PHYSICAL: A single physical engine, described by
* i915_gem_proto_engine::engine.
* - I915_GEM_ENGINE_TYPE_BALANCED: A load-balanced engine set, described
* i915_gem_proto_engine::num_siblings and i915_gem_proto_engine::siblings.
* - I915_GEM_ENGINE_TYPE_PARALLEL: A parallel submission engine set, described
* i915_gem_proto_engine::width, i915_gem_proto_engine::num_siblings, and
* i915_gem_proto_engine::siblings.
struct i915_gem_proto_engine {
/** @type: Type of this engine */
enum i915_gem_engine_type type;
/** @engine: Engine, for physical */
struct intel_engine_cs *engine;
/** @num_siblings: Number of balanced or parallel siblings */
unsigned int num_siblings;
/** @width: Width of each sibling */
unsigned int width;
/** @siblings: Balanced siblings or num_siblings * width for parallel */
struct intel_engine_cs **siblings;
/** @sseu: Client-set SSEU parameters */
struct intel_sseu sseu;
* struct i915_gem_proto_context - prototype context
* The struct i915_gem_proto_context represents the creation parameters for
* a struct i915_gem_context. This is used to gather parameters provided
* either through creation flags or via SET_CONTEXT_PARAM so that, when we
* create the final i915_gem_context, those parameters can be immutable.
* The context uAPI allows for two methods of setting context parameters:
* allowed to be called at any time while the later happens as part of
* GEM_CONTEXT_CREATE. When these were initially added, Currently,
* everything settable via one is settable via the other. While some
* params are fairly simple and setting them on a live context is harmless
* such the context priority, others are far trickier such as the VM or the
* set of engines. To avoid some truly nasty race conditions, we don't
* allow setting the VM or the set of engines on live contexts.
* The way we dealt with this without breaking older userspace that sets
* the VM or engine set via SET_CONTEXT_PARAM is to delay the creation of
* the actual context until after the client is done configuring it with
* SET_CONTEXT_PARAM. From the perspective of the client, it has the same
* u32 context ID the whole time. From the perspective of i915, however,
* it's an i915_gem_proto_context right up until the point where we attempt
* to do something which the proto-context can't handle at which point the
* real context gets created.
* This is accomplished via a little xarray dance. When GEM_CONTEXT_CREATE
* is called, we create a proto-context, reserve a slot in context_xa but
* leave it NULL, the proto-context in the corresponding slot in
* proto_context_xa. Then, whenever we go to look up a context, we first
* check context_xa. If it's there, we return the i915_gem_context and
* we're done. If it's not, we look in proto_context_xa and, if we find it
* there, we create the actual context and kill the proto-context.
* At the time we made this change (April, 2021), we did a fairly complete
* audit of existing userspace to ensure this wouldn't break anything:
* - Mesa/i965 didn't use the engines or VM APIs at all
* - Mesa/ANV used the engines API but via CONTEXT_CREATE_EXT_SETPARAM and
* didn't use the VM API.
* - Mesa/iris didn't use the engines or VM APIs at all
* - The open-source compute-runtime didn't yet use the engines API but
* was always the second ioctl on that context, immediately following
* - The media driver sets engines and bonding/balancing via
* always the second ioctl on that context, immediately following
* GEM_CONTEXT_CREATE and setting engines immediately followed that.
* In order for this dance to work properly, any modification to an
* i915_gem_proto_context that is exposed to the client via
* drm_i915_file_private::proto_context_xa must be guarded by
* drm_i915_file_private::proto_context_lock. The exception is when a
* proto-context has not yet been exposed such as when handling
struct i915_gem_proto_context {
/** @vm: See &i915_gem_context.vm */
struct i915_address_space *vm;
/** @user_flags: See &i915_gem_context.user_flags */
unsigned long user_flags;
/** @sched: See &i915_gem_context.sched */
struct i915_sched_attr sched;
/** @num_user_engines: Number of user-specified engines or -1 */
int num_user_engines;
/** @user_engines: User-specified engines */
struct i915_gem_proto_engine *user_engines;
/** @legacy_rcs_sseu: Client-set SSEU parameters for the legacy RCS */
struct intel_sseu legacy_rcs_sseu;
/** @single_timeline: See See &i915_gem_context.syncobj */
bool single_timeline;
/** @uses_protected_content: See &i915_gem_context.uses_protected_content */
bool uses_protected_content;
/** @pxp_wakeref: See &i915_gem_context.pxp_wakeref */
intel_wakeref_t pxp_wakeref;
* struct i915_gem_context - client state
* The struct i915_gem_context represents the combined view of the driver and
* logical hardware state for a particular client.
struct i915_gem_context {
/** @i915: i915 device backpointer */
struct drm_i915_private *i915;
/** @file_priv: owning file descriptor */
struct drm_i915_file_private *file_priv;
* @engines: User defined engines for this context
* Various uAPI offer the ability to lookup up an
* index from this array to select an engine operate on.
* Multiple logically distinct instances of the same engine
* may be defined in the array, as well as composite virtual
* engines.
* Execbuf uses the I915_EXEC_RING_MASK as an index into this
* array to select which HW context + engine to execute on. For
* the default array, the user_ring_map[] is used to translate
* the legacy uABI onto the approprate index (e.g. both
* I915_EXEC_DEFAULT and I915_EXEC_RENDER select the same
* context, and I915_EXEC_BSD is weird). For a use defined
* array, execbuf uses I915_EXEC_RING_MASK as a plain index.
* User defined by I915_CONTEXT_PARAM_ENGINE (when the
* CONTEXT_USER_ENGINES flag is set).
struct i915_gem_engines __rcu *engines;
/** @engines_mutex: guards writes to engines */
struct mutex engines_mutex;
* @syncobj: Shared timeline syncobj
* When the SHARED_TIMELINE flag is set on context creation, we
* emulate a single timeline across all engines using this syncobj.
* For every execbuffer2 call, this syncobj is used as both an in-
* and out-fence. Unlike the real intel_timeline, this doesn't
* provide perfect atomic in-order guarantees if the client races
* with itself by calling execbuffer2 twice concurrently. However,
* if userspace races with itself, that's not likely to yield well-
* defined results anyway so we choose to not care.
struct drm_syncobj *syncobj;
* @vm: unique address space (GTT)
* In full-ppgtt mode, each context has its own address space ensuring
* complete seperation of one client from all others.
* In other modes, this is a NULL pointer with the expectation that
* the caller uses the shared global GTT.
struct i915_address_space *vm;
* @pid: process id of creator
* Note that who created the context may not be the principle user,
* as the context may be shared across a local socket. However,
* that should only affect the default context, all contexts created
* explicitly by the client are expected to be isolated.
struct pid *pid;
/** @link: place with &drm_i915_private.context_list */
struct list_head link;
* @ref: reference count
* A reference to a context is held by both the client who created it
* and on each request submitted to the hardware using the request
* (to ensure the hardware has access to the state until it has
* finished all pending writes). See i915_gem_context_get() and
* i915_gem_context_put() for access.
struct kref ref;
* @release_work:
* Work item for deferred cleanup, since i915_gem_context_put() tends to
* be called from hardirq context.
* FIXME: The only real reason for this is &i915_gem_engines.fence, all
* other callers are from process context and need at most some mild
* shuffling to pull the i915_gem_context_put() call out of a spinlock.
struct work_struct release_work;
* @rcu: rcu_head for deferred freeing.
struct rcu_head rcu;
* @user_flags: small set of booleans controlled by the user
unsigned long user_flags;
* @flags: small set of booleans
unsigned long flags;
* @uses_protected_content: context uses PXP-encrypted objects.
* This flag can only be set at ctx creation time and it's immutable for
* the lifetime of the context. See I915_CONTEXT_PARAM_PROTECTED_CONTENT
* in uapi/drm/i915_drm.h for more info on setting restrictions and
* expected behaviour of marked contexts.
bool uses_protected_content;
* @pxp_wakeref: wakeref to keep the device awake when PXP is in use
* PXP sessions are invalidated when the device is suspended, which in
* turns invalidates all contexts and objects using it. To keep the
* flow simple, we keep the device awake when contexts using PXP objects
* are in use. It is expected that the userspace application only uses
* PXP when the display is on, so taking a wakeref here shouldn't worsen
* our power metrics.
intel_wakeref_t pxp_wakeref;
/** @mutex: guards everything that isn't engines or handles_vma */
struct mutex mutex;
/** @sched: scheduler parameters */
struct i915_sched_attr sched;
/** @guilty_count: How many times this context has caused a GPU hang. */
atomic_t guilty_count;
* @active_count: How many times this context was active during a GPU
* hang, but did not cause it.
atomic_t active_count;
* @hang_timestamp: The last time(s) this context caused a GPU hang
unsigned long hang_timestamp[2];
#define CONTEXT_FAST_HANG_JIFFIES (120 * HZ) /* 3 hangs within 120s? Banned! */
/** @remap_slice: Bitmask of cache lines that need remapping */
u8 remap_slice;
* @handles_vma: rbtree to look up our context specific obj/vma for
* the user handle. (user handles are per fd, but the binding is
* per vm, which may be one per context or shared with the global GTT)
struct radix_tree_root handles_vma;
/** @lut_mutex: Locks handles_vma */
struct mutex lut_mutex;
* @name: arbitrary name, used for user debug
* A name is constructed for the context from the creator's process
* name, pid and user handle in order to uniquely identify the
* context in messages.
char name[TASK_COMM_LEN + 8];
/** @stale: tracks stale engines to be destroyed */
struct {
/** @lock: guards engines */
spinlock_t lock;
/** @engines: list of stale engines */
struct list_head engines;
} stale;
#endif /* __I915_GEM_CONTEXT_TYPES_H__ */