blob: 952496c6260dfb5c3e9f798137cd4737a4040acb [file] [log] [blame]
// 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 dma_fence *rebind_fence;
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;
}
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 (!args->num_batch_buffer) {
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_exec;
}
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);
}
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.
*/
rebind_fence = xe_vm_rebind(vm, false);
if (IS_ERR(rebind_fence)) {
err = PTR_ERR(rebind_fence);
goto err_put_job;
}
/*
* We store the rebind_fence in the VM so subsequent execs don't get
* scheduled before the rebinds of userptrs / evicted BOs is complete.
*/
if (rebind_fence) {
dma_fence_put(vm->rebind_fence);
vm->rebind_fence = rebind_fence;
}
if (vm->rebind_fence) {
if (test_bit(DMA_FENCE_FLAG_SIGNALED_BIT,
&vm->rebind_fence->flags)) {
dma_fence_put(vm->rebind_fence);
vm->rebind_fence = NULL;
} else {
dma_fence_get(vm->rebind_fence);
err = drm_sched_job_add_dependency(&job->drm,
vm->rebind_fence);
if (err)
goto err_put_job;
}
}
/* Wait behind munmap style 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;
}