[Intel-xe] [PATCH v3 4/5] drm/xe: Allow num_batch_buffer == 0 in exec IOCTL

[Thomas Hellström]

On Tue, 2023-12-05 at 12:37 -0800, Matthew Brost wrote:
> The idea being out-syncs can signal indicating all previous
> operations
> on the exec queue are complete. An example use case of this would be
> support for implementing vkQueueWaitIdle easily.
> 
> v2: Don't add last_fence for VM's that do not support dma fences
> v3: Use a flags field instead of severval bools in sync parse

s/severval/several/
> (Thomas)
> v4: s/vkQueueWaitForIdle/vkQueueWaitIdle
> v5: Fix inverted lr_mode checks
> 
> Signed-off-by: Matthew Brost <matthew.brost at intel.com>
> ---
>  drivers/gpu/drm/xe/xe_exec.c             | 17 ++++++++++++++++-
>  drivers/gpu/drm/xe/xe_exec_queue.c       |  5 ++++-
>  drivers/gpu/drm/xe/xe_exec_queue_types.h |  5 +++--
>  drivers/gpu/drm/xe/xe_sync.c             |  4 ++++
>  4 files changed, 27 insertions(+), 4 deletions(-)

Reviewed-by: Thomas Hellström <thomas.hellstrom at linux.intel.com>

> 
> diff --git a/drivers/gpu/drm/xe/xe_exec.c
> b/drivers/gpu/drm/xe/xe_exec.c
> index a8a025495b14..96d7506a4c72 100644
> --- a/drivers/gpu/drm/xe/xe_exec.c
> +++ b/drivers/gpu/drm/xe/xe_exec.c
> @@ -161,7 +161,8 @@ int xe_exec_ioctl(struct drm_device *dev, void
> *data, struct drm_file *file)
>         if (XE_IOCTL_DBG(xe, q->flags & EXEC_QUEUE_FLAG_VM))
>                 return -EINVAL;
>  
> -       if (XE_IOCTL_DBG(xe, q->width != args->num_batch_buffer))
> +       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)) {
> @@ -235,6 +236,18 @@ int xe_exec_ioctl(struct drm_device *dev, void
> *data, struct drm_file *file)
>                 goto err_exec;
>         }
>  
> +       if (!args->num_batch_buffer) {
> +               if (!xe_vm_in_lr_mode(vm)) {
> +                       struct dma_fence *fence =
> +                               xe_exec_queue_last_fence_get(q, vm);
> +
> +                       for (i = 0; i < num_syncs; i++)
> +                               xe_sync_entry_signal(&syncs[i], NULL,
> fence);
> +               }
> +
> +               goto err_exec;
> +       }
> +
>         if (xe_exec_queue_is_lr(q) && xe_exec_queue_ring_full(q)) {
>                 err = -EWOULDBLOCK;
>                 goto err_exec;
> @@ -328,6 +341,8 @@ int xe_exec_ioctl(struct drm_device *dev, void
> *data, struct drm_file *file)
>  
>         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);
>  
> diff --git a/drivers/gpu/drm/xe/xe_exec_queue.c
> b/drivers/gpu/drm/xe/xe_exec_queue.c
> index cb284c4ad049..67e3fd9dfc5f 100644
> --- a/drivers/gpu/drm/xe/xe_exec_queue.c
> +++ b/drivers/gpu/drm/xe/xe_exec_queue.c
> @@ -886,7 +886,10 @@ int xe_exec_queue_destroy_ioctl(struct
> drm_device *dev, void *data,
>  static void xe_exec_queue_last_fence_lockdep_assert(struct
> xe_exec_queue *q,
>                                                     struct xe_vm *vm)
>  {
> -       lockdep_assert_held_write(&vm->lock);
> +       if (q->flags & EXEC_QUEUE_FLAG_VM)
> +               lockdep_assert_held_write(&vm->lock);
> +       else
> +               xe_vm_assert_held(vm);
>  }
>  
>  /**
> diff --git a/drivers/gpu/drm/xe/xe_exec_queue_types.h
> b/drivers/gpu/drm/xe/xe_exec_queue_types.h
> index 5ba47a5cfdbd..52f0927d0d9b 100644
> --- a/drivers/gpu/drm/xe/xe_exec_queue_types.h
> +++ b/drivers/gpu/drm/xe/xe_exec_queue_types.h
> @@ -56,8 +56,9 @@ struct xe_exec_queue {
>         struct xe_hw_fence_irq *fence_irq;
>  
>         /**
> -        * @last_fence: last fence on engine, protected by vm->lock
> in write
> -        * mode if bind engine
> +        * @last_fence: last fence on exec queue, protected by vm-
> >lock in write
> +        * mode if bind exec queue, protected by dma resv lock if
> non-bind exec
> +        * queue
>          */
>         struct dma_fence *last_fence;
>  
> diff --git a/drivers/gpu/drm/xe/xe_sync.c
> b/drivers/gpu/drm/xe/xe_sync.c
> index 2a3f508722fc..d0f118223fa2 100644
> --- a/drivers/gpu/drm/xe/xe_sync.c
> +++ b/drivers/gpu/drm/xe/xe_sync.c
> @@ -104,6 +104,7 @@ int xe_sync_entry_parse(struct xe_device *xe,
> struct xe_file *xef,
>         int err;
>         bool exec = flags & SYNC_PARSE_FLAG_EXEC;
>         bool in_lr_mode = flags & SYNC_PARSE_FLAG_LR_MODE;
> +       bool disallow_user_fence = flags &
> SYNC_PARSE_FLAG_DISALLOW_USER_FENCE;
>         bool signal;
>  
>         if (copy_from_user(&sync_in, sync_user, sizeof(*sync_user)))
> @@ -164,6 +165,9 @@ int xe_sync_entry_parse(struct xe_device *xe,
> struct xe_file *xef,
>                 break;
>  
>         case DRM_XE_SYNC_TYPE_USER_FENCE:
> +               if (XE_IOCTL_DBG(xe, disallow_user_fence))
> +                       return -EOPNOTSUPP;
> +
>                 if (XE_IOCTL_DBG(xe, !signal))
>                         return -EOPNOTSUPP;
>