1 /* 2 * SPDX-License-Identifier: MIT 3 * 4 * Copyright © 2019 Intel Corporation 5 */ 6 7 #ifndef __I915_GEM_CONTEXT_TYPES_H__ 8 #define __I915_GEM_CONTEXT_TYPES_H__ 9 10 #include <linux/atomic.h> 11 #include <linux/list.h> 12 #include <linux/llist.h> 13 #include <linux/kref.h> 14 #include <linux/mutex.h> 15 #include <linux/radix-tree.h> 16 #include <linux/rbtree.h> 17 #include <linux/rcupdate.h> 18 #include <linux/types.h> 19 20 #include "gt/intel_context_types.h" 21 22 #include "i915_scheduler.h" 23 #include "i915_sw_fence.h" 24 25 struct pid; 26 27 struct drm_i915_private; 28 struct drm_i915_file_private; 29 struct i915_address_space; 30 struct intel_timeline; 31 struct intel_ring; 32 33 /** 34 * struct i915_gem_engines - A set of engines 35 */ 36 struct i915_gem_engines { 37 union { 38 /** @link: Link in i915_gem_context::stale::engines */ 39 struct list_head link; 40 41 /** @rcu: RCU to use when freeing */ 42 struct rcu_head rcu; 43 }; 44 45 /** @fence: Fence used for delayed destruction of engines */ 46 struct i915_sw_fence fence; 47 48 /** @ctx: i915_gem_context backpointer */ 49 struct i915_gem_context *ctx; 50 51 /** @num_engines: Number of engines in this set */ 52 unsigned int num_engines; 53 54 /** @engines: Array of engines */ 55 struct intel_context *engines[]; 56 }; 57 58 /** 59 * struct i915_gem_engines_iter - Iterator for an i915_gem_engines set 60 */ 61 struct i915_gem_engines_iter { 62 /** @idx: Index into i915_gem_engines::engines */ 63 unsigned int idx; 64 65 /** @engines: Engine set being iterated */ 66 const struct i915_gem_engines *engines; 67 }; 68 69 /** 70 * enum i915_gem_engine_type - Describes the type of an i915_gem_proto_engine 71 */ 72 enum i915_gem_engine_type { 73 /** @I915_GEM_ENGINE_TYPE_INVALID: An invalid engine */ 74 I915_GEM_ENGINE_TYPE_INVALID = 0, 75 76 /** @I915_GEM_ENGINE_TYPE_PHYSICAL: A single physical engine */ 77 I915_GEM_ENGINE_TYPE_PHYSICAL, 78 79 /** @I915_GEM_ENGINE_TYPE_BALANCED: A load-balanced engine set */ 80 I915_GEM_ENGINE_TYPE_BALANCED, 81 }; 82 83 /** 84 * struct i915_gem_proto_engine - prototype engine 85 * 86 * This struct describes an engine that a context may contain. Engines 87 * have three types: 88 * 89 * - I915_GEM_ENGINE_TYPE_INVALID: Invalid engines can be created but they 90 * show up as a NULL in i915_gem_engines::engines[i] and any attempt to 91 * use them by the user results in -EINVAL. They are also useful during 92 * proto-context construction because the client may create invalid 93 * engines and then set them up later as virtual engines. 94 * 95 * - I915_GEM_ENGINE_TYPE_PHYSICAL: A single physical engine, described by 96 * i915_gem_proto_engine::engine. 97 * 98 * - I915_GEM_ENGINE_TYPE_BALANCED: A load-balanced engine set, described 99 * i915_gem_proto_engine::num_siblings and i915_gem_proto_engine::siblings. 100 */ 101 struct i915_gem_proto_engine { 102 /** @type: Type of this engine */ 103 enum i915_gem_engine_type type; 104 105 /** @engine: Engine, for physical */ 106 struct intel_engine_cs *engine; 107 108 /** @num_siblings: Number of balanced siblings */ 109 unsigned int num_siblings; 110 111 /** @siblings: Balanced siblings */ 112 struct intel_engine_cs **siblings; 113 114 /** @sseu: Client-set SSEU parameters */ 115 struct intel_sseu sseu; 116 }; 117 118 /** 119 * struct i915_gem_proto_context - prototype context 120 * 121 * The struct i915_gem_proto_context represents the creation parameters for 122 * a struct i915_gem_context. This is used to gather parameters provided 123 * either through creation flags or via SET_CONTEXT_PARAM so that, when we 124 * create the final i915_gem_context, those parameters can be immutable. 125 * 126 * The context uAPI allows for two methods of setting context parameters: 127 * SET_CONTEXT_PARAM and CONTEXT_CREATE_EXT_SETPARAM. The former is 128 * allowed to be called at any time while the later happens as part of 129 * GEM_CONTEXT_CREATE. When these were initially added, Currently, 130 * everything settable via one is settable via the other. While some 131 * params are fairly simple and setting them on a live context is harmless 132 * such the context priority, others are far trickier such as the VM or the 133 * set of engines. To avoid some truly nasty race conditions, we don't 134 * allow setting the VM or the set of engines on live contexts. 135 * 136 * The way we dealt with this without breaking older userspace that sets 137 * the VM or engine set via SET_CONTEXT_PARAM is to delay the creation of 138 * the actual context until after the client is done configuring it with 139 * SET_CONTEXT_PARAM. From the perspective of the client, it has the same 140 * u32 context ID the whole time. From the perspective of i915, however, 141 * it's an i915_gem_proto_context right up until the point where we attempt 142 * to do something which the proto-context can't handle at which point the 143 * real context gets created. 144 * 145 * This is accomplished via a little xarray dance. When GEM_CONTEXT_CREATE 146 * is called, we create a proto-context, reserve a slot in context_xa but 147 * leave it NULL, the proto-context in the corresponding slot in 148 * proto_context_xa. Then, whenever we go to look up a context, we first 149 * check context_xa. If it's there, we return the i915_gem_context and 150 * we're done. If it's not, we look in proto_context_xa and, if we find it 151 * there, we create the actual context and kill the proto-context. 152 * 153 * At the time we made this change (April, 2021), we did a fairly complete 154 * audit of existing userspace to ensure this wouldn't break anything: 155 * 156 * - Mesa/i965 didn't use the engines or VM APIs at all 157 * 158 * - Mesa/ANV used the engines API but via CONTEXT_CREATE_EXT_SETPARAM and 159 * didn't use the VM API. 160 * 161 * - Mesa/iris didn't use the engines or VM APIs at all 162 * 163 * - The open-source compute-runtime didn't yet use the engines API but 164 * did use the VM API via SET_CONTEXT_PARAM. However, CONTEXT_SETPARAM 165 * was always the second ioctl on that context, immediately following 166 * GEM_CONTEXT_CREATE. 167 * 168 * - The media driver sets engines and bonding/balancing via 169 * SET_CONTEXT_PARAM. However, CONTEXT_SETPARAM to set the VM was 170 * always the second ioctl on that context, immediately following 171 * GEM_CONTEXT_CREATE and setting engines immediately followed that. 172 * 173 * In order for this dance to work properly, any modification to an 174 * i915_gem_proto_context that is exposed to the client via 175 * drm_i915_file_private::proto_context_xa must be guarded by 176 * drm_i915_file_private::proto_context_lock. The exception is when a 177 * proto-context has not yet been exposed such as when handling 178 * CONTEXT_CREATE_SET_PARAM during GEM_CONTEXT_CREATE. 179 */ 180 struct i915_gem_proto_context { 181 /** @vm: See &i915_gem_context.vm */ 182 struct i915_address_space *vm; 183 184 /** @user_flags: See &i915_gem_context.user_flags */ 185 unsigned long user_flags; 186 187 /** @sched: See &i915_gem_context.sched */ 188 struct i915_sched_attr sched; 189 190 /** @num_user_engines: Number of user-specified engines or -1 */ 191 int num_user_engines; 192 193 /** @user_engines: User-specified engines */ 194 struct i915_gem_proto_engine *user_engines; 195 196 /** @legacy_rcs_sseu: Client-set SSEU parameters for the legacy RCS */ 197 struct intel_sseu legacy_rcs_sseu; 198 199 /** @single_timeline: See See &i915_gem_context.syncobj */ 200 bool single_timeline; 201 }; 202 203 /** 204 * struct i915_gem_context - client state 205 * 206 * The struct i915_gem_context represents the combined view of the driver and 207 * logical hardware state for a particular client. 208 */ 209 struct i915_gem_context { 210 /** @i915: i915 device backpointer */ 211 struct drm_i915_private *i915; 212 213 /** @file_priv: owning file descriptor */ 214 struct drm_i915_file_private *file_priv; 215 216 /** 217 * @engines: User defined engines for this context 218 * 219 * Various uAPI offer the ability to lookup up an 220 * index from this array to select an engine operate on. 221 * 222 * Multiple logically distinct instances of the same engine 223 * may be defined in the array, as well as composite virtual 224 * engines. 225 * 226 * Execbuf uses the I915_EXEC_RING_MASK as an index into this 227 * array to select which HW context + engine to execute on. For 228 * the default array, the user_ring_map[] is used to translate 229 * the legacy uABI onto the approprate index (e.g. both 230 * I915_EXEC_DEFAULT and I915_EXEC_RENDER select the same 231 * context, and I915_EXEC_BSD is weird). For a use defined 232 * array, execbuf uses I915_EXEC_RING_MASK as a plain index. 233 * 234 * User defined by I915_CONTEXT_PARAM_ENGINE (when the 235 * CONTEXT_USER_ENGINES flag is set). 236 */ 237 struct i915_gem_engines __rcu *engines; 238 239 /** @engines_mutex: guards writes to engines */ 240 struct mutex engines_mutex; 241 242 /** 243 * @syncobj: Shared timeline syncobj 244 * 245 * When the SHARED_TIMELINE flag is set on context creation, we 246 * emulate a single timeline across all engines using this syncobj. 247 * For every execbuffer2 call, this syncobj is used as both an in- 248 * and out-fence. Unlike the real intel_timeline, this doesn't 249 * provide perfect atomic in-order guarantees if the client races 250 * with itself by calling execbuffer2 twice concurrently. However, 251 * if userspace races with itself, that's not likely to yield well- 252 * defined results anyway so we choose to not care. 253 */ 254 struct drm_syncobj *syncobj; 255 256 /** 257 * @vm: unique address space (GTT) 258 * 259 * In full-ppgtt mode, each context has its own address space ensuring 260 * complete seperation of one client from all others. 261 * 262 * In other modes, this is a NULL pointer with the expectation that 263 * the caller uses the shared global GTT. 264 */ 265 struct i915_address_space __rcu *vm; 266 267 /** 268 * @pid: process id of creator 269 * 270 * Note that who created the context may not be the principle user, 271 * as the context may be shared across a local socket. However, 272 * that should only affect the default context, all contexts created 273 * explicitly by the client are expected to be isolated. 274 */ 275 struct pid *pid; 276 277 /** @link: place with &drm_i915_private.context_list */ 278 struct list_head link; 279 280 /** 281 * @ref: reference count 282 * 283 * A reference to a context is held by both the client who created it 284 * and on each request submitted to the hardware using the request 285 * (to ensure the hardware has access to the state until it has 286 * finished all pending writes). See i915_gem_context_get() and 287 * i915_gem_context_put() for access. 288 */ 289 struct kref ref; 290 291 /** 292 * @rcu: rcu_head for deferred freeing. 293 */ 294 struct rcu_head rcu; 295 296 /** 297 * @user_flags: small set of booleans controlled by the user 298 */ 299 unsigned long user_flags; 300 #define UCONTEXT_NO_ERROR_CAPTURE 1 301 #define UCONTEXT_BANNABLE 2 302 #define UCONTEXT_RECOVERABLE 3 303 #define UCONTEXT_PERSISTENCE 4 304 305 /** 306 * @flags: small set of booleans 307 */ 308 unsigned long flags; 309 #define CONTEXT_CLOSED 0 310 #define CONTEXT_USER_ENGINES 1 311 312 /** @mutex: guards everything that isn't engines or handles_vma */ 313 struct mutex mutex; 314 315 /** @sched: scheduler parameters */ 316 struct i915_sched_attr sched; 317 318 /** @guilty_count: How many times this context has caused a GPU hang. */ 319 atomic_t guilty_count; 320 /** 321 * @active_count: How many times this context was active during a GPU 322 * hang, but did not cause it. 323 */ 324 atomic_t active_count; 325 326 /** 327 * @hang_timestamp: The last time(s) this context caused a GPU hang 328 */ 329 unsigned long hang_timestamp[2]; 330 #define CONTEXT_FAST_HANG_JIFFIES (120 * HZ) /* 3 hangs within 120s? Banned! */ 331 332 /** @remap_slice: Bitmask of cache lines that need remapping */ 333 u8 remap_slice; 334 335 /** 336 * @handles_vma: rbtree to look up our context specific obj/vma for 337 * the user handle. (user handles are per fd, but the binding is 338 * per vm, which may be one per context or shared with the global GTT) 339 */ 340 struct radix_tree_root handles_vma; 341 342 /** @lut_mutex: Locks handles_vma */ 343 struct mutex lut_mutex; 344 345 /** 346 * @name: arbitrary name, used for user debug 347 * 348 * A name is constructed for the context from the creator's process 349 * name, pid and user handle in order to uniquely identify the 350 * context in messages. 351 */ 352 char name[TASK_COMM_LEN + 8]; 353 354 /** @stale: tracks stale engines to be destroyed */ 355 struct { 356 /** @lock: guards engines */ 357 spinlock_t lock; 358 /** @engines: list of stale engines */ 359 struct list_head engines; 360 } stale; 361 }; 362 363 #endif /* __I915_GEM_CONTEXT_TYPES_H__ */ 364