| // SPDX-License-Identifier: MIT |
| /* |
| * Copyright © 2022 Intel Corporation |
| */ |
| |
| #include "xe_exec.h" |
| |
| #include <drm/drm_device.h> |
| #include <drm/drm_exec.h> |
| #include <drm/drm_file.h> |
| #include <drm/xe_drm.h> |
| #include <linux/delay.h> |
| |
| #include "xe_bo.h" |
| #include "xe_device.h" |
| #include "xe_exec_queue.h" |
| #include "xe_macros.h" |
| #include "xe_ring_ops_types.h" |
| #include "xe_sched_job.h" |
| #include "xe_sync.h" |
| #include "xe_vm.h" |
| |
| /** |
| * DOC: Execbuf (User GPU command submission) |
| * |
| * Execs have historically been rather complicated in DRM drivers (at least in |
| * the i915) because a few things: |
| * |
| * - Passing in a list BO which are read / written to creating implicit syncs |
| * - Binding at exec time |
| * - Flow controlling the ring at exec time |
| * |
| * In XE we avoid all of this complication by not allowing a BO list to be |
| * passed into an exec, using the dma-buf implicit sync uAPI, have binds as |
| * seperate operations, and using the DRM scheduler to flow control the ring. |
| * Let's deep dive on each of these. |
| * |
| * We can get away from a BO list by forcing the user to use in / out fences on |
| * every exec rather than the kernel tracking dependencies of BO (e.g. if the |
| * user knows an exec writes to a BO and reads from the BO in the next exec, it |
| * is the user's responsibility to pass in / out fence between the two execs). |
| * |
| * Implicit dependencies for external BOs are handled by using the dma-buf |
| * implicit dependency uAPI (TODO: add link). To make this works each exec must |
| * install the job's fence into the DMA_RESV_USAGE_WRITE slot of every external |
| * BO mapped in the VM. |
| * |
| * We do not allow a user to trigger a bind at exec time rather we have a VM |
| * bind IOCTL which uses the same in / out fence interface as exec. In that |
| * sense, a VM bind is basically the same operation as an exec from the user |
| * perspective. e.g. If an exec depends on a VM bind use the in / out fence |
| * interface (struct drm_xe_sync) to synchronize like syncing between two |
| * dependent execs. |
| * |
| * Although a user cannot trigger a bind, we still have to rebind userptrs in |
| * the VM that have been invalidated since the last exec, likewise we also have |
| * to rebind BOs that have been evicted by the kernel. We schedule these rebinds |
| * behind any pending kernel operations on any external BOs in VM or any BOs |
| * private to the VM. This is accomplished by the rebinds waiting on BOs |
| * DMA_RESV_USAGE_KERNEL slot (kernel ops) and kernel ops waiting on all BOs |
| * slots (inflight execs are in the DMA_RESV_USAGE_BOOKING for private BOs and |
| * in DMA_RESV_USAGE_WRITE for external BOs). |
| * |
| * Rebinds / dma-resv usage applies to non-compute mode VMs only as for compute |
| * mode VMs we use preempt fences and a rebind worker (TODO: add link). |
| * |
| * There is no need to flow control the ring in the exec as we write the ring at |
| * submission time and set the DRM scheduler max job limit SIZE_OF_RING / |
| * MAX_JOB_SIZE. The DRM scheduler will then hold all jobs until space in the |
| * ring is available. |
| * |
| * All of this results in a rather simple exec implementation. |
| * |
| * Flow |
| * ~~~~ |
| * |
| * .. code-block:: |
| * |
| * Parse input arguments |
| * Wait for any async VM bind passed as in-fences to start |
| * <----------------------------------------------------------------------| |
| * Lock global VM lock in read mode | |
| * Pin userptrs (also finds userptr invalidated since last exec) | |
| * Lock exec (VM dma-resv lock, external BOs dma-resv locks) | |
| * Validate BOs that have been evicted | |
| * Create job | |
| * Rebind invalidated userptrs + evicted BOs (non-compute-mode) | |
| * Add rebind fence dependency to job | |
| * Add job VM dma-resv bookkeeping slot (non-compute mode) | |
| * Add job to external BOs dma-resv write slots (non-compute mode) | |
| * Check if any userptrs invalidated since pin ------ Drop locks ---------| |
| * Install in / out fences for job |
| * Submit job |
| * Unlock all |
| */ |
| |
| static int xe_exec_fn(struct drm_gpuvm_exec *vm_exec) |
| { |
| struct xe_vm *vm = container_of(vm_exec->vm, struct xe_vm, gpuvm); |
| struct drm_gem_object *obj; |
| unsigned long index; |
| int num_fences; |
| int ret; |
| |
| ret = drm_gpuvm_validate(vm_exec->vm, &vm_exec->exec); |
| if (ret) |
| return ret; |
| |
| /* |
| * 1 fence slot for the final submit, and 1 more for every per-tile for |
| * GPU bind and 1 extra for CPU bind. Note that there are potentially |
| * many vma per object/dma-resv, however the fence slot will just be |
| * re-used, since they are largely the same timeline and the seqno |
| * should be in order. In the case of CPU bind there is dummy fence used |
| * for all CPU binds, so no need to have a per-tile slot for that. |
| */ |
| num_fences = 1 + 1 + vm->xe->info.tile_count; |
| |
| /* |
| * We don't know upfront exactly how many fence slots we will need at |
| * the start of the exec, since the TTM bo_validate above can consume |
| * numerous fence slots. Also due to how the dma_resv_reserve_fences() |
| * works it only ensures that at least that many fence slots are |
| * available i.e if there are already 10 slots available and we reserve |
| * two more, it can just noop without reserving anything. With this it |
| * is quite possible that TTM steals some of the fence slots and then |
| * when it comes time to do the vma binding and final exec stage we are |
| * lacking enough fence slots, leading to some nasty BUG_ON() when |
| * adding the fences. Hence just add our own fences here, after the |
| * validate stage. |
| */ |
| drm_exec_for_each_locked_object(&vm_exec->exec, index, obj) { |
| ret = dma_resv_reserve_fences(obj->resv, num_fences); |
| if (ret) |
| return ret; |
| } |
| |
| return 0; |
| } |
| |
| int xe_exec_ioctl(struct drm_device *dev, void *data, struct drm_file *file) |
| { |
| struct xe_device *xe = to_xe_device(dev); |
| struct xe_file *xef = to_xe_file(file); |
| struct drm_xe_exec *args = data; |
| struct drm_xe_sync __user *syncs_user = u64_to_user_ptr(args->syncs); |
| u64 __user *addresses_user = u64_to_user_ptr(args->address); |
| struct xe_exec_queue *q; |
| struct xe_sync_entry *syncs = NULL; |
| u64 addresses[XE_HW_ENGINE_MAX_INSTANCE]; |
| struct drm_gpuvm_exec vm_exec = {.extra.fn = xe_exec_fn}; |
| struct drm_exec *exec = &vm_exec.exec; |
| u32 i, num_syncs = 0, num_ufence = 0; |
| struct xe_sched_job *job; |
| struct xe_vm *vm; |
| bool write_locked, skip_retry = false; |
| ktime_t end = 0; |
| int err = 0; |
| |
| if (XE_IOCTL_DBG(xe, args->extensions) || |
| XE_IOCTL_DBG(xe, args->pad[0] || args->pad[1] || args->pad[2]) || |
| XE_IOCTL_DBG(xe, args->reserved[0] || args->reserved[1])) |
| return -EINVAL; |
| |
| q = xe_exec_queue_lookup(xef, args->exec_queue_id); |
| if (XE_IOCTL_DBG(xe, !q)) |
| return -ENOENT; |
| |
| if (XE_IOCTL_DBG(xe, q->flags & EXEC_QUEUE_FLAG_VM)) |
| return -EINVAL; |
| |
| if (XE_IOCTL_DBG(xe, args->num_batch_buffer && |
| q->width != args->num_batch_buffer)) |
| return -EINVAL; |
| |
| if (XE_IOCTL_DBG(xe, q->flags & EXEC_QUEUE_FLAG_BANNED)) { |
| err = -ECANCELED; |
| goto err_exec_queue; |
| } |
| |
| if (args->num_syncs) { |
| syncs = kcalloc(args->num_syncs, sizeof(*syncs), GFP_KERNEL); |
| if (!syncs) { |
| err = -ENOMEM; |
| goto err_exec_queue; |
| } |
| } |
| |
| vm = q->vm; |
| |
| for (i = 0; i < args->num_syncs; i++) { |
| err = xe_sync_entry_parse(xe, xef, &syncs[num_syncs++], |
| &syncs_user[i], SYNC_PARSE_FLAG_EXEC | |
| (xe_vm_in_lr_mode(vm) ? |
| SYNC_PARSE_FLAG_LR_MODE : 0)); |
| if (err) |
| goto err_syncs; |
| |
| if (xe_sync_is_ufence(&syncs[i])) |
| num_ufence++; |
| } |
| |
| if (XE_IOCTL_DBG(xe, num_ufence > 1)) { |
| err = -EINVAL; |
| goto err_syncs; |
| } |
| |
| if (xe_exec_queue_is_parallel(q)) { |
| err = __copy_from_user(addresses, addresses_user, sizeof(u64) * |
| q->width); |
| if (err) { |
| err = -EFAULT; |
| goto err_syncs; |
| } |
| } |
| |
| retry: |
| if (!xe_vm_in_lr_mode(vm) && xe_vm_userptr_check_repin(vm)) { |
| err = down_write_killable(&vm->lock); |
| write_locked = true; |
| } else { |
| /* We don't allow execs while the VM is in error state */ |
| err = down_read_interruptible(&vm->lock); |
| write_locked = false; |
| } |
| if (err) |
| goto err_syncs; |
| |
| if (write_locked) { |
| err = xe_vm_userptr_pin(vm); |
| downgrade_write(&vm->lock); |
| write_locked = false; |
| if (err) |
| goto err_unlock_list; |
| } |
| |
| if (!args->num_batch_buffer) { |
| err = xe_vm_lock(vm, true); |
| if (err) |
| goto err_unlock_list; |
| |
| if (!xe_vm_in_lr_mode(vm)) { |
| struct dma_fence *fence; |
| |
| fence = xe_sync_in_fence_get(syncs, num_syncs, q, vm); |
| if (IS_ERR(fence)) { |
| err = PTR_ERR(fence); |
| goto err_unlock_list; |
| } |
| for (i = 0; i < num_syncs; i++) |
| xe_sync_entry_signal(&syncs[i], NULL, fence); |
| xe_exec_queue_last_fence_set(q, vm, fence); |
| dma_fence_put(fence); |
| } |
| |
| xe_vm_unlock(vm); |
| goto err_unlock_list; |
| } |
| |
| vm_exec.vm = &vm->gpuvm; |
| vm_exec.flags = DRM_EXEC_INTERRUPTIBLE_WAIT; |
| if (xe_vm_in_lr_mode(vm)) { |
| drm_exec_init(exec, vm_exec.flags, 0); |
| } else { |
| err = drm_gpuvm_exec_lock(&vm_exec); |
| if (err) { |
| if (xe_vm_validate_should_retry(exec, err, &end)) |
| err = -EAGAIN; |
| goto err_unlock_list; |
| } |
| } |
| |
| if (xe_vm_is_closed_or_banned(q->vm)) { |
| drm_warn(&xe->drm, "Trying to schedule after vm is closed or banned\n"); |
| err = -ECANCELED; |
| goto err_exec; |
| } |
| |
| if (xe_exec_queue_is_lr(q) && xe_exec_queue_ring_full(q)) { |
| err = -EWOULDBLOCK; /* Aliased to -EAGAIN */ |
| skip_retry = true; |
| goto err_exec; |
| } |
| |
| job = xe_sched_job_create(q, xe_exec_queue_is_parallel(q) ? |
| addresses : &args->address); |
| if (IS_ERR(job)) { |
| err = PTR_ERR(job); |
| goto err_exec; |
| } |
| |
| /* |
| * Rebind any invalidated userptr or evicted BOs in the VM, non-compute |
| * VM mode only. |
| */ |
| err = xe_vm_rebind(vm, false); |
| if (err) |
| goto err_put_job; |
| |
| /* Wait behind rebinds */ |
| if (!xe_vm_in_lr_mode(vm)) { |
| err = drm_sched_job_add_resv_dependencies(&job->drm, |
| xe_vm_resv(vm), |
| DMA_RESV_USAGE_KERNEL); |
| if (err) |
| goto err_put_job; |
| } |
| |
| for (i = 0; i < num_syncs && !err; i++) |
| err = xe_sync_entry_add_deps(&syncs[i], job); |
| if (err) |
| goto err_put_job; |
| |
| if (!xe_vm_in_lr_mode(vm)) { |
| err = xe_sched_job_last_fence_add_dep(job, vm); |
| if (err) |
| goto err_put_job; |
| |
| err = down_read_interruptible(&vm->userptr.notifier_lock); |
| if (err) |
| goto err_put_job; |
| |
| err = __xe_vm_userptr_needs_repin(vm); |
| if (err) |
| goto err_repin; |
| } |
| |
| /* |
| * Point of no return, if we error after this point just set an error on |
| * the job and let the DRM scheduler / backend clean up the job. |
| */ |
| xe_sched_job_arm(job); |
| if (!xe_vm_in_lr_mode(vm)) |
| drm_gpuvm_resv_add_fence(&vm->gpuvm, exec, &job->drm.s_fence->finished, |
| DMA_RESV_USAGE_BOOKKEEP, DMA_RESV_USAGE_WRITE); |
| |
| for (i = 0; i < num_syncs; i++) |
| xe_sync_entry_signal(&syncs[i], job, |
| &job->drm.s_fence->finished); |
| |
| if (xe_exec_queue_is_lr(q)) |
| q->ring_ops->emit_job(job); |
| if (!xe_vm_in_lr_mode(vm)) |
| xe_exec_queue_last_fence_set(q, vm, &job->drm.s_fence->finished); |
| xe_sched_job_push(job); |
| xe_vm_reactivate_rebind(vm); |
| |
| if (!err && !xe_vm_in_lr_mode(vm)) { |
| spin_lock(&xe->ttm.lru_lock); |
| ttm_lru_bulk_move_tail(&vm->lru_bulk_move); |
| spin_unlock(&xe->ttm.lru_lock); |
| } |
| |
| err_repin: |
| if (!xe_vm_in_lr_mode(vm)) |
| up_read(&vm->userptr.notifier_lock); |
| err_put_job: |
| if (err) |
| xe_sched_job_put(job); |
| err_exec: |
| drm_exec_fini(exec); |
| err_unlock_list: |
| if (write_locked) |
| up_write(&vm->lock); |
| else |
| up_read(&vm->lock); |
| if (err == -EAGAIN && !skip_retry) |
| goto retry; |
| err_syncs: |
| for (i = 0; i < num_syncs; i++) |
| xe_sync_entry_cleanup(&syncs[i]); |
| kfree(syncs); |
| err_exec_queue: |
| xe_exec_queue_put(q); |
| |
| return err; |
| } |