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