1 // SPDX-License-Identifier: MIT 2 /* 3 * Copyright © 2022 Intel Corporation 4 */ 5 6 #include "xe_exec.h" 7 8 #include <drm/drm_device.h> 9 #include <drm/drm_exec.h> 10 #include <drm/drm_file.h> 11 #include <uapi/drm/xe_drm.h> 12 #include <linux/delay.h> 13 14 #include "xe_bo.h" 15 #include "xe_device.h" 16 #include "xe_exec_queue.h" 17 #include "xe_hw_engine_group.h" 18 #include "xe_macros.h" 19 #include "xe_ring_ops_types.h" 20 #include "xe_sched_job.h" 21 #include "xe_sync.h" 22 #include "xe_vm.h" 23 24 /** 25 * DOC: Execbuf (User GPU command submission) 26 * 27 * Execs have historically been rather complicated in DRM drivers (at least in 28 * the i915) because a few things: 29 * 30 * - Passing in a list BO which are read / written to creating implicit syncs 31 * - Binding at exec time 32 * - Flow controlling the ring at exec time 33 * 34 * In XE we avoid all of this complication by not allowing a BO list to be 35 * passed into an exec, using the dma-buf implicit sync uAPI, have binds as 36 * seperate operations, and using the DRM scheduler to flow control the ring. 37 * Let's deep dive on each of these. 38 * 39 * We can get away from a BO list by forcing the user to use in / out fences on 40 * every exec rather than the kernel tracking dependencies of BO (e.g. if the 41 * user knows an exec writes to a BO and reads from the BO in the next exec, it 42 * is the user's responsibility to pass in / out fence between the two execs). 43 * 44 * Implicit dependencies for external BOs are handled by using the dma-buf 45 * implicit dependency uAPI (TODO: add link). To make this works each exec must 46 * install the job's fence into the DMA_RESV_USAGE_WRITE slot of every external 47 * BO mapped in the VM. 48 * 49 * We do not allow a user to trigger a bind at exec time rather we have a VM 50 * bind IOCTL which uses the same in / out fence interface as exec. In that 51 * sense, a VM bind is basically the same operation as an exec from the user 52 * perspective. e.g. If an exec depends on a VM bind use the in / out fence 53 * interface (struct drm_xe_sync) to synchronize like syncing between two 54 * dependent execs. 55 * 56 * Although a user cannot trigger a bind, we still have to rebind userptrs in 57 * the VM that have been invalidated since the last exec, likewise we also have 58 * to rebind BOs that have been evicted by the kernel. We schedule these rebinds 59 * behind any pending kernel operations on any external BOs in VM or any BOs 60 * private to the VM. This is accomplished by the rebinds waiting on BOs 61 * DMA_RESV_USAGE_KERNEL slot (kernel ops) and kernel ops waiting on all BOs 62 * slots (inflight execs are in the DMA_RESV_USAGE_BOOKING for private BOs and 63 * in DMA_RESV_USAGE_WRITE for external BOs). 64 * 65 * Rebinds / dma-resv usage applies to non-compute mode VMs only as for compute 66 * mode VMs we use preempt fences and a rebind worker (TODO: add link). 67 * 68 * There is no need to flow control the ring in the exec as we write the ring at 69 * submission time and set the DRM scheduler max job limit SIZE_OF_RING / 70 * MAX_JOB_SIZE. The DRM scheduler will then hold all jobs until space in the 71 * ring is available. 72 * 73 * All of this results in a rather simple exec implementation. 74 * 75 * Flow 76 * ~~~~ 77 * 78 * .. code-block:: 79 * 80 * Parse input arguments 81 * Wait for any async VM bind passed as in-fences to start 82 * <----------------------------------------------------------------------| 83 * Lock global VM lock in read mode | 84 * Pin userptrs (also finds userptr invalidated since last exec) | 85 * Lock exec (VM dma-resv lock, external BOs dma-resv locks) | 86 * Validate BOs that have been evicted | 87 * Create job | 88 * Rebind invalidated userptrs + evicted BOs (non-compute-mode) | 89 * Add rebind fence dependency to job | 90 * Add job VM dma-resv bookkeeping slot (non-compute mode) | 91 * Add job to external BOs dma-resv write slots (non-compute mode) | 92 * Check if any userptrs invalidated since pin ------ Drop locks ---------| 93 * Install in / out fences for job 94 * Submit job 95 * Unlock all 96 */ 97 98 /* 99 * Add validation and rebinding to the drm_exec locking loop, since both can 100 * trigger eviction which may require sleeping dma_resv locks. 101 */ 102 static int xe_exec_fn(struct drm_gpuvm_exec *vm_exec) 103 { 104 struct xe_vm *vm = container_of(vm_exec->vm, struct xe_vm, gpuvm); 105 106 /* The fence slot added here is intended for the exec sched job. */ 107 return xe_vm_validate_rebind(vm, &vm_exec->exec, 1); 108 } 109 110 int xe_exec_ioctl(struct drm_device *dev, void *data, struct drm_file *file) 111 { 112 struct xe_device *xe = to_xe_device(dev); 113 struct xe_file *xef = to_xe_file(file); 114 struct drm_xe_exec *args = data; 115 struct drm_xe_sync __user *syncs_user = u64_to_user_ptr(args->syncs); 116 u64 __user *addresses_user = u64_to_user_ptr(args->address); 117 struct xe_exec_queue *q; 118 struct xe_sync_entry *syncs = NULL; 119 u64 addresses[XE_HW_ENGINE_MAX_INSTANCE]; 120 struct drm_gpuvm_exec vm_exec = {.extra.fn = xe_exec_fn}; 121 struct drm_exec *exec = &vm_exec.exec; 122 u32 i, num_syncs, num_ufence = 0; 123 struct xe_sched_job *job; 124 struct xe_vm *vm; 125 bool write_locked, skip_retry = false; 126 ktime_t end = 0; 127 int err = 0; 128 struct xe_hw_engine_group *group; 129 enum xe_hw_engine_group_execution_mode mode, previous_mode; 130 131 if (XE_IOCTL_DBG(xe, args->extensions) || 132 XE_IOCTL_DBG(xe, args->pad[0] || args->pad[1] || args->pad[2]) || 133 XE_IOCTL_DBG(xe, args->reserved[0] || args->reserved[1])) 134 return -EINVAL; 135 136 q = xe_exec_queue_lookup(xef, args->exec_queue_id); 137 if (XE_IOCTL_DBG(xe, !q)) 138 return -ENOENT; 139 140 if (XE_IOCTL_DBG(xe, q->flags & EXEC_QUEUE_FLAG_VM)) 141 return -EINVAL; 142 143 if (XE_IOCTL_DBG(xe, args->num_batch_buffer && 144 q->width != args->num_batch_buffer)) 145 return -EINVAL; 146 147 if (XE_IOCTL_DBG(xe, q->ops->reset_status(q))) { 148 err = -ECANCELED; 149 goto err_exec_queue; 150 } 151 152 if (args->num_syncs) { 153 syncs = kcalloc(args->num_syncs, sizeof(*syncs), GFP_KERNEL); 154 if (!syncs) { 155 err = -ENOMEM; 156 goto err_exec_queue; 157 } 158 } 159 160 vm = q->vm; 161 162 for (num_syncs = 0; num_syncs < args->num_syncs; num_syncs++) { 163 err = xe_sync_entry_parse(xe, xef, &syncs[num_syncs], 164 &syncs_user[num_syncs], SYNC_PARSE_FLAG_EXEC | 165 (xe_vm_in_lr_mode(vm) ? 166 SYNC_PARSE_FLAG_LR_MODE : 0)); 167 if (err) 168 goto err_syncs; 169 170 if (xe_sync_is_ufence(&syncs[num_syncs])) 171 num_ufence++; 172 } 173 174 if (XE_IOCTL_DBG(xe, num_ufence > 1)) { 175 err = -EINVAL; 176 goto err_syncs; 177 } 178 179 if (xe_exec_queue_is_parallel(q)) { 180 err = __copy_from_user(addresses, addresses_user, sizeof(u64) * 181 q->width); 182 if (err) { 183 err = -EFAULT; 184 goto err_syncs; 185 } 186 } 187 188 group = q->hwe->hw_engine_group; 189 mode = xe_hw_engine_group_find_exec_mode(q); 190 191 if (mode == EXEC_MODE_DMA_FENCE) { 192 err = xe_hw_engine_group_get_mode(group, mode, &previous_mode); 193 if (err) 194 goto err_syncs; 195 } 196 197 retry: 198 if (!xe_vm_in_lr_mode(vm) && xe_vm_userptr_check_repin(vm)) { 199 err = down_write_killable(&vm->lock); 200 write_locked = true; 201 } else { 202 /* We don't allow execs while the VM is in error state */ 203 err = down_read_interruptible(&vm->lock); 204 write_locked = false; 205 } 206 if (err) 207 goto err_syncs; 208 209 if (write_locked) { 210 err = xe_vm_userptr_pin(vm); 211 downgrade_write(&vm->lock); 212 write_locked = false; 213 if (err) 214 goto err_hw_exec_mode; 215 } 216 217 if (!args->num_batch_buffer) { 218 err = xe_vm_lock(vm, true); 219 if (err) 220 goto err_unlock_list; 221 222 if (!xe_vm_in_lr_mode(vm)) { 223 struct dma_fence *fence; 224 225 fence = xe_sync_in_fence_get(syncs, num_syncs, q, vm); 226 if (IS_ERR(fence)) { 227 err = PTR_ERR(fence); 228 goto err_unlock_list; 229 } 230 for (i = 0; i < num_syncs; i++) 231 xe_sync_entry_signal(&syncs[i], fence); 232 xe_exec_queue_last_fence_set(q, vm, fence); 233 dma_fence_put(fence); 234 } 235 236 xe_vm_unlock(vm); 237 goto err_unlock_list; 238 } 239 240 vm_exec.vm = &vm->gpuvm; 241 vm_exec.flags = DRM_EXEC_INTERRUPTIBLE_WAIT; 242 if (xe_vm_in_lr_mode(vm)) { 243 drm_exec_init(exec, vm_exec.flags, 0); 244 } else { 245 err = drm_gpuvm_exec_lock(&vm_exec); 246 if (err) { 247 if (xe_vm_validate_should_retry(exec, err, &end)) 248 err = -EAGAIN; 249 goto err_unlock_list; 250 } 251 } 252 253 if (xe_vm_is_closed_or_banned(q->vm)) { 254 drm_warn(&xe->drm, "Trying to schedule after vm is closed or banned\n"); 255 err = -ECANCELED; 256 goto err_exec; 257 } 258 259 if (xe_exec_queue_is_lr(q) && xe_exec_queue_ring_full(q)) { 260 err = -EWOULDBLOCK; /* Aliased to -EAGAIN */ 261 skip_retry = true; 262 goto err_exec; 263 } 264 265 job = xe_sched_job_create(q, xe_exec_queue_is_parallel(q) ? 266 addresses : &args->address); 267 if (IS_ERR(job)) { 268 err = PTR_ERR(job); 269 goto err_exec; 270 } 271 272 /* Wait behind rebinds */ 273 if (!xe_vm_in_lr_mode(vm)) { 274 err = xe_sched_job_add_deps(job, 275 xe_vm_resv(vm), 276 DMA_RESV_USAGE_KERNEL); 277 if (err) 278 goto err_put_job; 279 } 280 281 for (i = 0; i < num_syncs && !err; i++) 282 err = xe_sync_entry_add_deps(&syncs[i], job); 283 if (err) 284 goto err_put_job; 285 286 if (!xe_vm_in_lr_mode(vm)) { 287 err = xe_sched_job_last_fence_add_dep(job, vm); 288 if (err) 289 goto err_put_job; 290 291 err = down_read_interruptible(&vm->userptr.notifier_lock); 292 if (err) 293 goto err_put_job; 294 295 err = __xe_vm_userptr_needs_repin(vm); 296 if (err) 297 goto err_repin; 298 } 299 300 /* 301 * Point of no return, if we error after this point just set an error on 302 * the job and let the DRM scheduler / backend clean up the job. 303 */ 304 xe_sched_job_arm(job); 305 if (!xe_vm_in_lr_mode(vm)) 306 drm_gpuvm_resv_add_fence(&vm->gpuvm, exec, &job->drm.s_fence->finished, 307 DMA_RESV_USAGE_BOOKKEEP, DMA_RESV_USAGE_WRITE); 308 309 for (i = 0; i < num_syncs; i++) { 310 xe_sync_entry_signal(&syncs[i], &job->drm.s_fence->finished); 311 xe_sched_job_init_user_fence(job, &syncs[i]); 312 } 313 314 if (xe_exec_queue_is_lr(q)) 315 q->ring_ops->emit_job(job); 316 if (!xe_vm_in_lr_mode(vm)) 317 xe_exec_queue_last_fence_set(q, vm, &job->drm.s_fence->finished); 318 xe_sched_job_push(job); 319 xe_vm_reactivate_rebind(vm); 320 321 if (!err && !xe_vm_in_lr_mode(vm)) { 322 spin_lock(&xe->ttm.lru_lock); 323 ttm_lru_bulk_move_tail(&vm->lru_bulk_move); 324 spin_unlock(&xe->ttm.lru_lock); 325 } 326 327 if (mode == EXEC_MODE_LR) 328 xe_hw_engine_group_resume_faulting_lr_jobs(group); 329 330 err_repin: 331 if (!xe_vm_in_lr_mode(vm)) 332 up_read(&vm->userptr.notifier_lock); 333 err_put_job: 334 if (err) 335 xe_sched_job_put(job); 336 err_exec: 337 drm_exec_fini(exec); 338 err_unlock_list: 339 up_read(&vm->lock); 340 if (err == -EAGAIN && !skip_retry) 341 goto retry; 342 err_hw_exec_mode: 343 if (mode == EXEC_MODE_DMA_FENCE) 344 xe_hw_engine_group_put(group); 345 err_syncs: 346 while (num_syncs--) 347 xe_sync_entry_cleanup(&syncs[num_syncs]); 348 kfree(syncs); 349 err_exec_queue: 350 xe_exec_queue_put(q); 351 352 return err; 353 } 354