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// 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 <uapi/drm/xe_drm.h>
#include <linux/delay.h>
#include "xe_bo.h"
#include "xe_device.h"
#include "xe_exec_queue.h"
#include "xe_hw_engine_group.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).
*
* 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_BOOKKEEP for private BOs and
* 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
*/
/*
* Add validation and rebinding to the drm_exec locking loop, since both can
* trigger eviction which may require sleeping dma_resv locks.
*/
static int xe_exec_fn(struct drm_gpuvm_exec *vm_exec)
{
struct xe_vm *vm = container_of(vm_exec->vm, struct xe_vm, gpuvm);
/* The fence slot added here is intended for the exec sched job. */
return xe_vm_validate_rebind(vm, &vm_exec->exec, 1);
}
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, 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;
struct xe_hw_engine_group *group;
enum xe_hw_engine_group_execution_mode mode, previous_mode;
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)) {
err = -EINVAL;
goto err_exec_queue;
}
if (XE_IOCTL_DBG(xe, args->num_batch_buffer &&
q->width != args->num_batch_buffer)) {
err = -EINVAL;
goto err_exec_queue;
}
if (XE_IOCTL_DBG(xe, q->ops->reset_status(q))) {
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 (num_syncs = 0; num_syncs < args->num_syncs; num_syncs++) {
err = xe_sync_entry_parse(xe, xef, &syncs[num_syncs],
&syncs_user[num_syncs], 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[num_syncs]))
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;
}
}
group = q->hwe->hw_engine_group;
mode = xe_hw_engine_group_find_exec_mode(q);
if (mode == EXEC_MODE_DMA_FENCE) {
err = xe_hw_engine_group_get_mode(group, mode, &previous_mode);
if (err)
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_hw_exec_mode;
}
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);
xe_vm_unlock(vm);
goto err_unlock_list;
}
for (i = 0; i < num_syncs; i++)
xe_sync_entry_signal(&syncs[i], 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;
}
/* Wait behind rebinds */
if (!xe_vm_in_lr_mode(vm)) {
err = xe_sched_job_add_deps(job,
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_BOOKKEEP);
for (i = 0; i < num_syncs; i++) {
xe_sync_entry_signal(&syncs[i], &job->drm.s_fence->finished);
xe_sched_job_init_user_fence(job, &syncs[i]);
}
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);
}
if (mode == EXEC_MODE_LR)
xe_hw_engine_group_resume_faulting_lr_jobs(group);
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:
up_read(&vm->lock);
if (err == -EAGAIN && !skip_retry)
goto retry;
err_hw_exec_mode:
if (mode == EXEC_MODE_DMA_FENCE)
xe_hw_engine_group_put(group);
err_syncs:
while (num_syncs--)
xe_sync_entry_cleanup(&syncs[num_syncs]);
kfree(syncs);
err_exec_queue:
xe_exec_queue_put(q);
return err;
}
|