[20/25] drm/i915: Multi-BB execbuf

Commit Message

Matthew Brost Oct. 13, 2021, 8:42 p.m. UTC

Allow multiple batch buffers to be submitted in a single execbuf IOCTL
after a context has been configured with the 'set_parallel' extension.
The number batches is implicit based on the contexts configuration.

This is implemented with a series of loops. First a loop is used to find
all the batches, a loop to pin all the HW contexts, a loop to create all
the requests, a loop to submit (emit BB start, etc...) all the requests,
a loop to tie the requests to the VMAs they touch, and finally a loop to
commit the requests to the backend.

A composite fence is also created for the generated requests to return
to the user and to stick in dma resv slots.

No behavior from the existing IOCTL should be changed aside from when
throttling because the ring for a context is full. In this situation,
i915 will now wait while holding the object locks. This change was done
because the code is much simpler to wait while holding the locks and we
believe there isn't a huge benefit of dropping these locks. If this
proves false we can restructure the code to drop the locks during the
wait.

IGT: https://patchwork.freedesktop.org/patch/447008/?series=93071&rev=1
media UMD: https://github.com/intel/media-driver/pull/1252

v2:
 (Matthew Brost)
  - Return proper error value if i915_request_create fails
v3:
 (John Harrison)
  - Add comment explaining create / add order loops + locking
  - Update commit message explaining different in IOCTL behavior
  - Line wrap some comments
  - eb_add_request returns void
  - Return -EINVAL rather triggering BUG_ON if cmd parser used
 (Checkpatch)
  - Check eb->batch_len[*current_batch]
v4:
 (CI)
  - Set batch len if passed if via execbuf args
  - Call __i915_request_skip after __i915_request_commit
 (Kernel test robot)
  - Initialize rq to NULL in eb_pin_timeline

Signed-off-by: Matthew Brost <[e-mail]>
---
 .../gpu/drm/i915/gem/i915_gem_execbuffer.c    | 783 ++++++++++++------
 drivers/gpu/drm/i915/gt/intel_context.h       |   8 +-
 drivers/gpu/drm/i915/gt/intel_context_types.h |  10 +
 .../gpu/drm/i915/gt/uc/intel_guc_submission.c |   2 +
 drivers/gpu/drm/i915/i915_request.h           |   9 +
 drivers/gpu/drm/i915/i915_vma.c               |  21 +-
 drivers/gpu/drm/i915/i915_vma.h               |  13 +-
 7 files changed, 595 insertions(+), 251 deletions(-)

Comments

John Harrison Oct. 14, 2021, 12:55 a.m. UTC | #1

On 10/13/2021 13:42, Matthew Brost wrote:
> Allow multiple batch buffers to be submitted in a single execbuf IOCTL
> after a context has been configured with the 'set_parallel' extension.
> The number batches is implicit based on the contexts configuration.
>
> This is implemented with a series of loops. First a loop is used to find
> all the batches, a loop to pin all the HW contexts, a loop to create all
> the requests, a loop to submit (emit BB start, etc...) all the requests,
> a loop to tie the requests to the VMAs they touch, and finally a loop to
> commit the requests to the backend.
>
> A composite fence is also created for the generated requests to return
> to the user and to stick in dma resv slots.
>
> No behavior from the existing IOCTL should be changed aside from when
> throttling because the ring for a context is full. In this situation,
> i915 will now wait while holding the object locks. This change was done
> because the code is much simpler to wait while holding the locks and we
> believe there isn't a huge benefit of dropping these locks. If this
> proves false we can restructure the code to drop the locks during the
> wait.
>
> IGT: https://patchwork.freedesktop.org/patch/447008/?series=93071&rev=1
> media UMD: https://github.com/intel/media-driver/pull/1252
>
> v2:
>   (Matthew Brost)
>    - Return proper error value if i915_request_create fails
> v3:
>   (John Harrison)
>    - Add comment explaining create / add order loops + locking
>    - Update commit message explaining different in IOCTL behavior
>    - Line wrap some comments
>    - eb_add_request returns void
>    - Return -EINVAL rather triggering BUG_ON if cmd parser used
>   (Checkpatch)
>    - Check eb->batch_len[*current_batch]
> v4:
>   (CI)
>    - Set batch len if passed if via execbuf args
>    - Call __i915_request_skip after __i915_request_commit
>   (Kernel test robot)
>    - Initialize rq to NULL in eb_pin_timeline
>
> Signed-off-by: Matthew Brost <[e-mail]>
> ---
>   .../gpu/drm/i915/gem/i915_gem_execbuffer.c    | 783 ++++++++++++------
>   drivers/gpu/drm/i915/gt/intel_context.h       |   8 +-
>   drivers/gpu/drm/i915/gt/intel_context_types.h |  10 +
>   .../gpu/drm/i915/gt/uc/intel_guc_submission.c |   2 +
>   drivers/gpu/drm/i915/i915_request.h           |   9 +
>   drivers/gpu/drm/i915/i915_vma.c               |  21 +-
>   drivers/gpu/drm/i915/i915_vma.h               |  13 +-
>   7 files changed, 595 insertions(+), 251 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c
> index c75afc8784e3..6509c9d8c298 100644
> --- a/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c
> +++ b/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c
> @@ -246,17 +246,25 @@ struct i915_execbuffer {
>   	struct drm_i915_gem_exec_object2 *exec; /** ioctl execobj[] */
>   	struct eb_vma *vma;
>   
> -	struct intel_engine_cs *engine; /** engine to queue the request to */
> +	struct intel_gt *gt; /* gt for the execbuf */
>   	struct intel_context *context; /* logical state for the request */
>   	struct i915_gem_context *gem_context; /** caller's context */
>   
> -	struct i915_request *request; /** our request to build */
> -	struct eb_vma *batch; /** identity of the batch obj/vma */
> +	/** our requests to build */
> +	struct i915_request *requests[MAX_ENGINE_INSTANCE + 1];
> +	/** identity of the batch obj/vma */
> +	struct eb_vma *batches[MAX_ENGINE_INSTANCE + 1];
>   	struct i915_vma *trampoline; /** trampoline used for chaining */
>   
> +	/** used for excl fence in dma_resv objects when > 1 BB submitted */
> +	struct dma_fence *composite_fence;
> +
>   	/** actual size of execobj[] as we may extend it for the cmdparser */
>   	unsigned int buffer_count;
>   
> +	/* number of batches in execbuf IOCTL */
> +	unsigned int num_batches;
> +
>   	/** list of vma not yet bound during reservation phase */
>   	struct list_head unbound;
>   
> @@ -283,7 +291,8 @@ struct i915_execbuffer {
>   
>   	u64 invalid_flags; /** Set of execobj.flags that are invalid */
>   
> -	u64 batch_len; /** Length of batch within object */
> +	/** Length of batch within object */
> +	u64 batch_len[MAX_ENGINE_INSTANCE + 1];
>   	u32 batch_start_offset; /** Location within object of batch */
>   	u32 batch_flags; /** Flags composed for emit_bb_start() */
>   	struct intel_gt_buffer_pool_node *batch_pool; /** pool node for batch buffer */
> @@ -301,14 +310,13 @@ struct i915_execbuffer {
>   };
>   
>   static int eb_parse(struct i915_execbuffer *eb);
> -static struct i915_request *eb_pin_engine(struct i915_execbuffer *eb,
> -					  bool throttle);
> +static int eb_pin_engine(struct i915_execbuffer *eb, bool throttle);
>   static void eb_unpin_engine(struct i915_execbuffer *eb);
>   
>   static inline bool eb_use_cmdparser(const struct i915_execbuffer *eb)
>   {
> -	return intel_engine_requires_cmd_parser(eb->engine) ||
> -		(intel_engine_using_cmd_parser(eb->engine) &&
> +	return intel_engine_requires_cmd_parser(eb->context->engine) ||
> +		(intel_engine_using_cmd_parser(eb->context->engine) &&
>   		 eb->args->batch_len);
>   }
>   
> @@ -546,11 +554,21 @@ eb_validate_vma(struct i915_execbuffer *eb,
>   	return 0;
>   }
>   
> -static void
> +static inline bool
> +is_batch_buffer(struct i915_execbuffer *eb, unsigned int buffer_idx)
> +{
> +	return eb->args->flags & I915_EXEC_BATCH_FIRST ?
> +		buffer_idx < eb->num_batches :
> +		buffer_idx >= eb->args->buffer_count - eb->num_batches;
> +}
> +
> +static int
>   eb_add_vma(struct i915_execbuffer *eb,
> -	   unsigned int i, unsigned batch_idx,
> +	   unsigned int *current_batch,
> +	   unsigned int i,
>   	   struct i915_vma *vma)
>   {
> +	struct drm_i915_private *i915 = eb->i915;
>   	struct drm_i915_gem_exec_object2 *entry = &eb->exec[i];
>   	struct eb_vma *ev = &eb->vma[i];
>   
> @@ -577,15 +595,43 @@ eb_add_vma(struct i915_execbuffer *eb,
>   	 * Note that actual hangs have only been observed on gen7, but for
>   	 * paranoia do it everywhere.
>   	 */
> -	if (i == batch_idx) {
> +	if (is_batch_buffer(eb, i)) {
>   		if (entry->relocation_count &&
>   		    !(ev->flags & EXEC_OBJECT_PINNED))
>   			ev->flags |= __EXEC_OBJECT_NEEDS_BIAS;
>   		if (eb->reloc_cache.has_fence)
>   			ev->flags |= EXEC_OBJECT_NEEDS_FENCE;
>   
> -		eb->batch = ev;
> +		eb->batches[*current_batch] = ev;
> +
> +		if (unlikely(ev->flags & EXEC_OBJECT_WRITE)) {
> +			drm_dbg(&i915->drm,
> +				"Attempting to use self-modifying batch buffer\n");
> +			return -EINVAL;
> +		}
> +
> +		if (range_overflows_t(u64,
> +				      eb->batch_start_offset,
> +				      eb->args->batch_len,
> +				      ev->vma->size)) {
> +			drm_dbg(&i915->drm, "Attempting to use out-of-bounds batch\n");
> +			return -EINVAL;
> +		}
> +
> +		if (eb->args->batch_len == 0)
> +			eb->batch_len[*current_batch] = ev->vma->size -
> +				eb->batch_start_offset;
> +		else
> +			eb->batch_len[*current_batch] = eb->args->batch_len;
> +		if (unlikely(eb->batch_len[*current_batch] == 0)) { /* impossible! */
> +			drm_dbg(&i915->drm, "Invalid batch length\n");
> +			return -EINVAL;
> +		}
> +
> +		++*current_batch;
>   	}
> +
> +	return 0;
>   }
>   
>   static inline int use_cpu_reloc(const struct reloc_cache *cache,
> @@ -729,14 +775,6 @@ static int eb_reserve(struct i915_execbuffer *eb)
>   	} while (1);
>   }
>   
> -static unsigned int eb_batch_index(const struct i915_execbuffer *eb)
> -{
> -	if (eb->args->flags & I915_EXEC_BATCH_FIRST)
> -		return 0;
> -	else
> -		return eb->buffer_count - 1;
> -}
> -
>   static int eb_select_context(struct i915_execbuffer *eb)
>   {
>   	struct i915_gem_context *ctx;
> @@ -857,9 +895,7 @@ static struct i915_vma *eb_lookup_vma(struct i915_execbuffer *eb, u32 handle)
>   
>   static int eb_lookup_vmas(struct i915_execbuffer *eb)
>   {
> -	struct drm_i915_private *i915 = eb->i915;
> -	unsigned int batch = eb_batch_index(eb);
> -	unsigned int i;
> +	unsigned int i, current_batch = 0;
>   	int err = 0;
>   
>   	INIT_LIST_HEAD(&eb->relocs);
> @@ -879,7 +915,9 @@ static int eb_lookup_vmas(struct i915_execbuffer *eb)
>   			goto err;
>   		}
>   
> -		eb_add_vma(eb, i, batch, vma);
> +		err = eb_add_vma(eb, &current_batch, i, vma);
> +		if (err)
> +			return err;
>   
>   		if (i915_gem_object_is_userptr(vma->obj)) {
>   			err = i915_gem_object_userptr_submit_init(vma->obj);
> @@ -902,26 +940,6 @@ static int eb_lookup_vmas(struct i915_execbuffer *eb)
>   		}
>   	}
>   
> -	if (unlikely(eb->batch->flags & EXEC_OBJECT_WRITE)) {
> -		drm_dbg(&i915->drm,
> -			"Attempting to use self-modifying batch buffer\n");
> -		return -EINVAL;
> -	}
> -
> -	if (range_overflows_t(u64,
> -			      eb->batch_start_offset, eb->batch_len,
> -			      eb->batch->vma->size)) {
> -		drm_dbg(&i915->drm, "Attempting to use out-of-bounds batch\n");
> -		return -EINVAL;
> -	}
> -
> -	if (eb->batch_len == 0)
> -		eb->batch_len = eb->batch->vma->size - eb->batch_start_offset;
> -	if (unlikely(eb->batch_len == 0)) { /* impossible! */
> -		drm_dbg(&i915->drm, "Invalid batch length\n");
> -		return -EINVAL;
> -	}
> -
>   	return 0;
>   
>   err:
> @@ -1654,8 +1672,7 @@ static int eb_reinit_userptr(struct i915_execbuffer *eb)
>   	return 0;
>   }
>   
> -static noinline int eb_relocate_parse_slow(struct i915_execbuffer *eb,
> -					   struct i915_request *rq)
> +static noinline int eb_relocate_parse_slow(struct i915_execbuffer *eb)
>   {
>   	bool have_copy = false;
>   	struct eb_vma *ev;
> @@ -1671,21 +1688,6 @@ static noinline int eb_relocate_parse_slow(struct i915_execbuffer *eb,
>   	eb_release_vmas(eb, false);
>   	i915_gem_ww_ctx_fini(&eb->ww);
>   
> -	if (rq) {
> -		/* nonblocking is always false */
> -		if (i915_request_wait(rq, I915_WAIT_INTERRUPTIBLE,
> -				      MAX_SCHEDULE_TIMEOUT) < 0) {
> -			i915_request_put(rq);
> -			rq = NULL;
> -
> -			err = -EINTR;
> -			goto err_relock;
> -		}
> -
> -		i915_request_put(rq);
> -		rq = NULL;
> -	}
> -
>   	/*
>   	 * We take 3 passes through the slowpatch.
>   	 *
> @@ -1712,28 +1714,21 @@ static noinline int eb_relocate_parse_slow(struct i915_execbuffer *eb,
>   	if (!err)
>   		err = eb_reinit_userptr(eb);
>   
> -err_relock:
>   	i915_gem_ww_ctx_init(&eb->ww, true);
>   	if (err)
>   		goto out;
>   
>   	/* reacquire the objects */
>   repeat_validate:
> -	rq = eb_pin_engine(eb, false);
> -	if (IS_ERR(rq)) {
> -		err = PTR_ERR(rq);
> -		rq = NULL;
> +	err = eb_pin_engine(eb, false);
> +	if (err)
>   		goto err;
> -	}
> -
> -	/* We didn't throttle, should be NULL */
> -	GEM_WARN_ON(rq);
>   
>   	err = eb_validate_vmas(eb);
>   	if (err)
>   		goto err;
>   
> -	GEM_BUG_ON(!eb->batch);
> +	GEM_BUG_ON(!eb->batches[0]);
>   
>   	list_for_each_entry(ev, &eb->relocs, reloc_link) {
>   		if (!have_copy) {
> @@ -1797,46 +1792,23 @@ static noinline int eb_relocate_parse_slow(struct i915_execbuffer *eb,
>   		}
>   	}
>   
> -	if (rq)
> -		i915_request_put(rq);
> -
>   	return err;
>   }
>   
>   static int eb_relocate_parse(struct i915_execbuffer *eb)
>   {
>   	int err;
> -	struct i915_request *rq = NULL;
>   	bool throttle = true;
>   
>   retry:
> -	rq = eb_pin_engine(eb, throttle);
> -	if (IS_ERR(rq)) {
> -		err = PTR_ERR(rq);
> -		rq = NULL;
> +	err = eb_pin_engine(eb, throttle);
> +	if (err) {
>   		if (err != -EDEADLK)
>   			return err;
>   
>   		goto err;
>   	}
>   
> -	if (rq) {
> -		bool nonblock = eb->file->filp->f_flags & O_NONBLOCK;
> -
> -		/* Need to drop all locks now for throttling, take slowpath */
> -		err = i915_request_wait(rq, I915_WAIT_INTERRUPTIBLE, 0);
> -		if (err == -ETIME) {
> -			if (nonblock) {
> -				err = -EWOULDBLOCK;
> -				i915_request_put(rq);
> -				goto err;
> -			}
> -			goto slow;
> -		}
> -		i915_request_put(rq);
> -		rq = NULL;
> -	}
> -
>   	/* only throttle once, even if we didn't need to throttle */
>   	throttle = false;
>   
> @@ -1876,7 +1848,7 @@ static int eb_relocate_parse(struct i915_execbuffer *eb)
>   	return err;
>   
>   slow:
> -	err = eb_relocate_parse_slow(eb, rq);
> +	err = eb_relocate_parse_slow(eb);
>   	if (err)
>   		/*
>   		 * If the user expects the execobject.offset and
> @@ -1890,11 +1862,40 @@ static int eb_relocate_parse(struct i915_execbuffer *eb)
>   	return err;
>   }
>   
> +/*
> + * Using two helper loops for the order of which requests / batches are created
> + * and added the to backend. Requests are created in order from the parent to
> + * the last child. Requests are add in the reverse order, from the last child to
are add -> are added

> + * parent. This is down from locking reasons as the timeline lock is acquired
down from -> done for?

John.

> + * during request creation and released when the request is added to the
> + * backend. To make lockdep happy (see intel_context_timeline_lock) this must be
> + * the ordering.
> + */
> +#define for_each_batch_create_order(_eb, _i) \
> +	for ((_i) = 0; (_i) < (_eb)->num_batches; ++(_i))
> +#define for_each_batch_add_order(_eb, _i) \
> +	BUILD_BUG_ON(!typecheck(int, _i)); \
> +	for ((_i) = (_eb)->num_batches - 1; (_i) >= 0; --(_i))
> +
> +static struct i915_request *
> +eb_find_first_request_added(struct i915_execbuffer *eb)
> +{
> +	int i;
> +
> +	for_each_batch_add_order(eb, i)
> +		if (eb->requests[i])
> +			return eb->requests[i];
> +
> +	GEM_BUG_ON("Request not found");
> +
> +	return NULL;
> +}
> +
>   static int eb_move_to_gpu(struct i915_execbuffer *eb)
>   {
>   	const unsigned int count = eb->buffer_count;
>   	unsigned int i = count;
> -	int err = 0;
> +	int err = 0, j;
>   
>   	while (i--) {
>   		struct eb_vma *ev = &eb->vma[i];
> @@ -1907,11 +1908,17 @@ static int eb_move_to_gpu(struct i915_execbuffer *eb)
>   		if (flags & EXEC_OBJECT_CAPTURE) {
>   			struct i915_capture_list *capture;
>   
> -			capture = kmalloc(sizeof(*capture), GFP_KERNEL);
> -			if (capture) {
> -				capture->next = eb->request->capture_list;
> -				capture->vma = vma;
> -				eb->request->capture_list = capture;
> +			for_each_batch_create_order(eb, j) {
> +				if (!eb->requests[j])
> +					break;
> +
> +				capture = kmalloc(sizeof(*capture), GFP_KERNEL);
> +				if (capture) {
> +					capture->next =
> +						eb->requests[j]->capture_list;
> +					capture->vma = vma;
> +					eb->requests[j]->capture_list = capture;
> +				}
>   			}
>   		}
>   
> @@ -1932,14 +1939,26 @@ static int eb_move_to_gpu(struct i915_execbuffer *eb)
>   				flags &= ~EXEC_OBJECT_ASYNC;
>   		}
>   
> +		/* We only need to await on the first request */
>   		if (err == 0 && !(flags & EXEC_OBJECT_ASYNC)) {
>   			err = i915_request_await_object
> -				(eb->request, obj, flags & EXEC_OBJECT_WRITE);
> +				(eb_find_first_request_added(eb), obj,
> +				 flags & EXEC_OBJECT_WRITE);
>   		}
>   
> -		if (err == 0)
> -			err = i915_vma_move_to_active(vma, eb->request,
> -						      flags | __EXEC_OBJECT_NO_RESERVE);
> +		for_each_batch_add_order(eb, j) {
> +			if (err)
> +				break;
> +			if (!eb->requests[j])
> +				continue;
> +
> +			err = _i915_vma_move_to_active(vma, eb->requests[j],
> +						       j ? NULL :
> +						       eb->composite_fence ?
> +						       eb->composite_fence :
> +						       &eb->requests[j]->fence,
> +						       flags | __EXEC_OBJECT_NO_RESERVE);
> +		}
>   	}
>   
>   #ifdef CONFIG_MMU_NOTIFIER
> @@ -1970,11 +1989,16 @@ static int eb_move_to_gpu(struct i915_execbuffer *eb)
>   		goto err_skip;
>   
>   	/* Unconditionally flush any chipset caches (for streaming writes). */
> -	intel_gt_chipset_flush(eb->engine->gt);
> +	intel_gt_chipset_flush(eb->gt);
>   	return 0;
>   
>   err_skip:
> -	i915_request_set_error_once(eb->request, err);
> +	for_each_batch_create_order(eb, j) {
> +		if (!eb->requests[j])
> +			break;
> +
> +		i915_request_set_error_once(eb->requests[j], err);
> +	}
>   	return err;
>   }
>   
> @@ -2069,14 +2093,17 @@ static int eb_parse(struct i915_execbuffer *eb)
>   	int err;
>   
>   	if (!eb_use_cmdparser(eb)) {
> -		batch = eb_dispatch_secure(eb, eb->batch->vma);
> +		batch = eb_dispatch_secure(eb, eb->batches[0]->vma);
>   		if (IS_ERR(batch))
>   			return PTR_ERR(batch);
>   
>   		goto secure_batch;
>   	}
>   
> -	len = eb->batch_len;
> +	if (intel_context_is_parallel(eb->context))
> +		return -EINVAL;
> +
> +	len = eb->batch_len[0];
>   	if (!CMDPARSER_USES_GGTT(eb->i915)) {
>   		/*
>   		 * ppGTT backed shadow buffers must be mapped RO, to prevent
> @@ -2090,11 +2117,11 @@ static int eb_parse(struct i915_execbuffer *eb)
>   	} else {
>   		len += I915_CMD_PARSER_TRAMPOLINE_SIZE;
>   	}
> -	if (unlikely(len < eb->batch_len)) /* last paranoid check of overflow */
> +	if (unlikely(len < eb->batch_len[0])) /* last paranoid check of overflow */
>   		return -EINVAL;
>   
>   	if (!pool) {
> -		pool = intel_gt_get_buffer_pool(eb->engine->gt, len,
> +		pool = intel_gt_get_buffer_pool(eb->gt, len,
>   						I915_MAP_WB);
>   		if (IS_ERR(pool))
>   			return PTR_ERR(pool);
> @@ -2119,7 +2146,7 @@ static int eb_parse(struct i915_execbuffer *eb)
>   		trampoline = shadow;
>   
>   		shadow = shadow_batch_pin(eb, pool->obj,
> -					  &eb->engine->gt->ggtt->vm,
> +					  &eb->gt->ggtt->vm,
>   					  PIN_GLOBAL);
>   		if (IS_ERR(shadow)) {
>   			err = PTR_ERR(shadow);
> @@ -2141,26 +2168,29 @@ static int eb_parse(struct i915_execbuffer *eb)
>   	if (err)
>   		goto err_trampoline;
>   
> -	err = intel_engine_cmd_parser(eb->engine,
> -				      eb->batch->vma,
> +	err = intel_engine_cmd_parser(eb->context->engine,
> +				      eb->batches[0]->vma,
>   				      eb->batch_start_offset,
> -				      eb->batch_len,
> +				      eb->batch_len[0],
>   				      shadow, trampoline);
>   	if (err)
>   		goto err_unpin_batch;
>   
> -	eb->batch = &eb->vma[eb->buffer_count++];
> -	eb->batch->vma = i915_vma_get(shadow);
> -	eb->batch->flags = __EXEC_OBJECT_HAS_PIN;
> +	eb->batches[0] = &eb->vma[eb->buffer_count++];
> +	eb->batches[0]->vma = i915_vma_get(shadow);
> +	eb->batches[0]->flags = __EXEC_OBJECT_HAS_PIN;
>   
>   	eb->trampoline = trampoline;
>   	eb->batch_start_offset = 0;
>   
>   secure_batch:
>   	if (batch) {
> -		eb->batch = &eb->vma[eb->buffer_count++];
> -		eb->batch->flags = __EXEC_OBJECT_HAS_PIN;
> -		eb->batch->vma = i915_vma_get(batch);
> +		if (intel_context_is_parallel(eb->context))
> +			return -EINVAL;
> +
> +		eb->batches[0] = &eb->vma[eb->buffer_count++];
> +		eb->batches[0]->flags = __EXEC_OBJECT_HAS_PIN;
> +		eb->batches[0]->vma = i915_vma_get(batch);
>   	}
>   	return 0;
>   
> @@ -2176,19 +2206,18 @@ static int eb_parse(struct i915_execbuffer *eb)
>   	return err;
>   }
>   
> -static int eb_submit(struct i915_execbuffer *eb, struct i915_vma *batch)
> +static int eb_request_submit(struct i915_execbuffer *eb,
> +			     struct i915_request *rq,
> +			     struct i915_vma *batch,
> +			     u64 batch_len)
>   {
>   	int err;
>   
> -	if (intel_context_nopreempt(eb->context))
> -		__set_bit(I915_FENCE_FLAG_NOPREEMPT, &eb->request->fence.flags);
> -
> -	err = eb_move_to_gpu(eb);
> -	if (err)
> -		return err;
> +	if (intel_context_nopreempt(rq->context))
> +		__set_bit(I915_FENCE_FLAG_NOPREEMPT, &rq->fence.flags);
>   
>   	if (eb->args->flags & I915_EXEC_GEN7_SOL_RESET) {
> -		err = i915_reset_gen7_sol_offsets(eb->request);
> +		err = i915_reset_gen7_sol_offsets(rq);
>   		if (err)
>   			return err;
>   	}
> @@ -2199,26 +2228,26 @@ static int eb_submit(struct i915_execbuffer *eb, struct i915_vma *batch)
>   	 * allows us to determine if the batch is still waiting on the GPU
>   	 * or actually running by checking the breadcrumb.
>   	 */
> -	if (eb->engine->emit_init_breadcrumb) {
> -		err = eb->engine->emit_init_breadcrumb(eb->request);
> +	if (rq->context->engine->emit_init_breadcrumb) {
> +		err = rq->context->engine->emit_init_breadcrumb(rq);
>   		if (err)
>   			return err;
>   	}
>   
> -	err = eb->engine->emit_bb_start(eb->request,
> -					batch->node.start +
> -					eb->batch_start_offset,
> -					eb->batch_len,
> -					eb->batch_flags);
> +	err = rq->context->engine->emit_bb_start(rq,
> +						 batch->node.start +
> +						 eb->batch_start_offset,
> +						 batch_len,
> +						 eb->batch_flags);
>   	if (err)
>   		return err;
>   
>   	if (eb->trampoline) {
> +		GEM_BUG_ON(intel_context_is_parallel(rq->context));
>   		GEM_BUG_ON(eb->batch_start_offset);
> -		err = eb->engine->emit_bb_start(eb->request,
> -						eb->trampoline->node.start +
> -						eb->batch_len,
> -						0, 0);
> +		err = rq->context->engine->emit_bb_start(rq,
> +							 eb->trampoline->node.start +
> +							 batch_len, 0, 0);
>   		if (err)
>   			return err;
>   	}
> @@ -2226,6 +2255,27 @@ static int eb_submit(struct i915_execbuffer *eb, struct i915_vma *batch)
>   	return 0;
>   }
>   
> +static int eb_submit(struct i915_execbuffer *eb)
> +{
> +	unsigned int i;
> +	int err;
> +
> +	err = eb_move_to_gpu(eb);
> +
> +	for_each_batch_create_order(eb, i) {
> +		if (!eb->requests[i])
> +			break;
> +
> +		trace_i915_request_queue(eb->requests[i], eb->batch_flags);
> +		if (!err)
> +			err = eb_request_submit(eb, eb->requests[i],
> +						eb->batches[i]->vma,
> +						eb->batch_len[i]);
> +	}
> +
> +	return err;
> +}
> +
>   static int num_vcs_engines(const struct drm_i915_private *i915)
>   {
>   	return hweight_long(VDBOX_MASK(&i915->gt));
> @@ -2291,26 +2341,11 @@ static struct i915_request *eb_throttle(struct i915_execbuffer *eb, struct intel
>   	return i915_request_get(rq);
>   }
>   
> -static struct i915_request *eb_pin_engine(struct i915_execbuffer *eb, bool throttle)
> +static int eb_pin_timeline(struct i915_execbuffer *eb, struct intel_context *ce,
> +			   bool throttle)
>   {
> -	struct intel_context *ce = eb->context;
>   	struct intel_timeline *tl;
>   	struct i915_request *rq = NULL;
> -	int err;
> -
> -	GEM_BUG_ON(eb->args->flags & __EXEC_ENGINE_PINNED);
> -
> -	if (unlikely(intel_context_is_banned(ce)))
> -		return ERR_PTR(-EIO);
> -
> -	/*
> -	 * Pinning the contexts may generate requests in order to acquire
> -	 * GGTT space, so do this first before we reserve a seqno for
> -	 * ourselves.
> -	 */
> -	err = intel_context_pin_ww(ce, &eb->ww);
> -	if (err)
> -		return ERR_PTR(err);
>   
>   	/*
>   	 * Take a local wakeref for preparing to dispatch the execbuf as
> @@ -2321,33 +2356,108 @@ static struct i915_request *eb_pin_engine(struct i915_execbuffer *eb, bool throt
>   	 * taken on the engine, and the parent device.
>   	 */
>   	tl = intel_context_timeline_lock(ce);
> -	if (IS_ERR(tl)) {
> -		intel_context_unpin(ce);
> -		return ERR_CAST(tl);
> -	}
> +	if (IS_ERR(tl))
> +		return PTR_ERR(tl);
>   
>   	intel_context_enter(ce);
>   	if (throttle)
>   		rq = eb_throttle(eb, ce);
>   	intel_context_timeline_unlock(tl);
>   
> +	if (rq) {
> +		bool nonblock = eb->file->filp->f_flags & O_NONBLOCK;
> +		long timeout = nonblock ? 0 : MAX_SCHEDULE_TIMEOUT;
> +
> +		if (i915_request_wait(rq, I915_WAIT_INTERRUPTIBLE,
> +				      timeout) < 0) {
> +			i915_request_put(rq);
> +
> +			tl = intel_context_timeline_lock(ce);
> +			intel_context_exit(ce);
> +			intel_context_timeline_unlock(tl);
> +
> +			if (nonblock)
> +				return -EWOULDBLOCK;
> +			else
> +				return -EINTR;
> +		}
> +		i915_request_put(rq);
> +	}
> +
> +	return 0;
> +}
> +
> +static int eb_pin_engine(struct i915_execbuffer *eb, bool throttle)
> +{
> +	struct intel_context *ce = eb->context, *child;
> +	int err;
> +	int i = 0, j = 0;
> +
> +	GEM_BUG_ON(eb->args->flags & __EXEC_ENGINE_PINNED);
> +
> +	if (unlikely(intel_context_is_banned(ce)))
> +		return -EIO;
> +
> +	/*
> +	 * Pinning the contexts may generate requests in order to acquire
> +	 * GGTT space, so do this first before we reserve a seqno for
> +	 * ourselves.
> +	 */
> +	err = intel_context_pin_ww(ce, &eb->ww);
> +	if (err)
> +		return err;
> +	for_each_child(ce, child) {
> +		err = intel_context_pin_ww(child, &eb->ww);
> +		GEM_BUG_ON(err);	/* perma-pinned should incr a counter */
> +	}
> +
> +	for_each_child(ce, child) {
> +		err = eb_pin_timeline(eb, child, throttle);
> +		if (err)
> +			goto unwind;
> +		++i;
> +	}
> +	err = eb_pin_timeline(eb, ce, throttle);
> +	if (err)
> +		goto unwind;
> +
>   	eb->args->flags |= __EXEC_ENGINE_PINNED;
> -	return rq;
> +	return 0;
> +
> +unwind:
> +	for_each_child(ce, child) {
> +		if (j++ < i) {
> +			mutex_lock(&child->timeline->mutex);
> +			intel_context_exit(child);
> +			mutex_unlock(&child->timeline->mutex);
> +		}
> +	}
> +	for_each_child(ce, child)
> +		intel_context_unpin(child);
> +	intel_context_unpin(ce);
> +	return err;
>   }
>   
>   static void eb_unpin_engine(struct i915_execbuffer *eb)
>   {
> -	struct intel_context *ce = eb->context;
> -	struct intel_timeline *tl = ce->timeline;
> +	struct intel_context *ce = eb->context, *child;
>   
>   	if (!(eb->args->flags & __EXEC_ENGINE_PINNED))
>   		return;
>   
>   	eb->args->flags &= ~__EXEC_ENGINE_PINNED;
>   
> -	mutex_lock(&tl->mutex);
> +	for_each_child(ce, child) {
> +		mutex_lock(&child->timeline->mutex);
> +		intel_context_exit(child);
> +		mutex_unlock(&child->timeline->mutex);
> +
> +		intel_context_unpin(child);
> +	}
> +
> +	mutex_lock(&ce->timeline->mutex);
>   	intel_context_exit(ce);
> -	mutex_unlock(&tl->mutex);
> +	mutex_unlock(&ce->timeline->mutex);
>   
>   	intel_context_unpin(ce);
>   }
> @@ -2398,7 +2508,7 @@ eb_select_legacy_ring(struct i915_execbuffer *eb)
>   static int
>   eb_select_engine(struct i915_execbuffer *eb)
>   {
> -	struct intel_context *ce;
> +	struct intel_context *ce, *child;
>   	unsigned int idx;
>   	int err;
>   
> @@ -2411,6 +2521,20 @@ eb_select_engine(struct i915_execbuffer *eb)
>   	if (IS_ERR(ce))
>   		return PTR_ERR(ce);
>   
> +	if (intel_context_is_parallel(ce)) {
> +		if (eb->buffer_count < ce->parallel.number_children + 1) {
> +			intel_context_put(ce);
> +			return -EINVAL;
> +		}
> +		if (eb->batch_start_offset || eb->args->batch_len) {
> +			intel_context_put(ce);
> +			return -EINVAL;
> +		}
> +	}
> +	eb->num_batches = ce->parallel.number_children + 1;
> +
> +	for_each_child(ce, child)
> +		intel_context_get(child);
>   	intel_gt_pm_get(ce->engine->gt);
>   
>   	if (!test_bit(CONTEXT_ALLOC_BIT, &ce->flags)) {
> @@ -2418,6 +2542,13 @@ eb_select_engine(struct i915_execbuffer *eb)
>   		if (err)
>   			goto err;
>   	}
> +	for_each_child(ce, child) {
> +		if (!test_bit(CONTEXT_ALLOC_BIT, &child->flags)) {
> +			err = intel_context_alloc_state(child);
> +			if (err)
> +				goto err;
> +		}
> +	}
>   
>   	/*
>   	 * ABI: Before userspace accesses the GPU (e.g. execbuffer), report
> @@ -2428,7 +2559,7 @@ eb_select_engine(struct i915_execbuffer *eb)
>   		goto err;
>   
>   	eb->context = ce;
> -	eb->engine = ce->engine;
> +	eb->gt = ce->engine->gt;
>   
>   	/*
>   	 * Make sure engine pool stays alive even if we call intel_context_put
> @@ -2439,6 +2570,8 @@ eb_select_engine(struct i915_execbuffer *eb)
>   
>   err:
>   	intel_gt_pm_put(ce->engine->gt);
> +	for_each_child(ce, child)
> +		intel_context_put(child);
>   	intel_context_put(ce);
>   	return err;
>   }
> @@ -2446,7 +2579,11 @@ eb_select_engine(struct i915_execbuffer *eb)
>   static void
>   eb_put_engine(struct i915_execbuffer *eb)
>   {
> -	intel_gt_pm_put(eb->engine->gt);
> +	struct intel_context *child;
> +
> +	intel_gt_pm_put(eb->gt);
> +	for_each_child(eb->context, child)
> +		intel_context_put(child);
>   	intel_context_put(eb->context);
>   }
>   
> @@ -2669,7 +2806,8 @@ static void put_fence_array(struct eb_fence *fences, int num_fences)
>   }
>   
>   static int
> -await_fence_array(struct i915_execbuffer *eb)
> +await_fence_array(struct i915_execbuffer *eb,
> +		  struct i915_request *rq)
>   {
>   	unsigned int n;
>   	int err;
> @@ -2683,8 +2821,7 @@ await_fence_array(struct i915_execbuffer *eb)
>   		if (!eb->fences[n].dma_fence)
>   			continue;
>   
> -		err = i915_request_await_dma_fence(eb->request,
> -						   eb->fences[n].dma_fence);
> +		err = i915_request_await_dma_fence(rq, eb->fences[n].dma_fence);
>   		if (err < 0)
>   			return err;
>   	}
> @@ -2692,9 +2829,9 @@ await_fence_array(struct i915_execbuffer *eb)
>   	return 0;
>   }
>   
> -static void signal_fence_array(const struct i915_execbuffer *eb)
> +static void signal_fence_array(const struct i915_execbuffer *eb,
> +			       struct dma_fence * const fence)
>   {
> -	struct dma_fence * const fence = &eb->request->fence;
>   	unsigned int n;
>   
>   	for (n = 0; n < eb->num_fences; n++) {
> @@ -2742,9 +2879,9 @@ static void retire_requests(struct intel_timeline *tl, struct i915_request *end)
>   			break;
>   }
>   
> -static int eb_request_add(struct i915_execbuffer *eb, int err)
> +static int eb_request_add(struct i915_execbuffer *eb, struct i915_request *rq,
> +			  int err, bool last_parallel)
>   {
> -	struct i915_request *rq = eb->request;
>   	struct intel_timeline * const tl = i915_request_timeline(rq);
>   	struct i915_sched_attr attr = {};
>   	struct i915_request *prev;
> @@ -2766,6 +2903,17 @@ static int eb_request_add(struct i915_execbuffer *eb, int err)
>   		err = -ENOENT; /* override any transient errors */
>   	}
>   
> +	if (intel_context_is_parallel(eb->context)) {
> +		if (err) {
> +			__i915_request_skip(rq);
> +			set_bit(I915_FENCE_FLAG_SKIP_PARALLEL,
> +				&rq->fence.flags);
> +		}
> +		if (last_parallel)
> +			set_bit(I915_FENCE_FLAG_SUBMIT_PARALLEL,
> +				&rq->fence.flags);
> +	}
> +
>   	__i915_request_queue(rq, &attr);
>   
>   	/* Try to clean up the client's timeline after submitting the request */
> @@ -2777,6 +2925,25 @@ static int eb_request_add(struct i915_execbuffer *eb, int err)
>   	return err;
>   }
>   
> +static int eb_requests_add(struct i915_execbuffer *eb, int err)
> +{
> +	int i;
> +
> +	/*
> +	 * We iterate in reverse order of creation to release timeline mutexes in
> +	 * same order.
> +	 */
> +	for_each_batch_add_order(eb, i) {
> +		struct i915_request *rq = eb->requests[i];
> +
> +		if (!rq)
> +			continue;
> +		err |= eb_request_add(eb, rq, err, i == 0);
> +	}
> +
> +	return err;
> +}
> +
>   static const i915_user_extension_fn execbuf_extensions[] = {
>   	[DRM_I915_GEM_EXECBUFFER_EXT_TIMELINE_FENCES] = parse_timeline_fences,
>   };
> @@ -2803,6 +2970,182 @@ parse_execbuf2_extensions(struct drm_i915_gem_execbuffer2 *args,
>   				    eb);
>   }
>   
> +static void eb_requests_get(struct i915_execbuffer *eb)
> +{
> +	unsigned int i;
> +
> +	for_each_batch_create_order(eb, i) {
> +		if (!eb->requests[i])
> +			break;
> +
> +		i915_request_get(eb->requests[i]);
> +	}
> +}
> +
> +static void eb_requests_put(struct i915_execbuffer *eb)
> +{
> +	unsigned int i;
> +
> +	for_each_batch_create_order(eb, i) {
> +		if (!eb->requests[i])
> +			break;
> +
> +		i915_request_put(eb->requests[i]);
> +	}
> +}
> +
> +static struct sync_file *
> +eb_composite_fence_create(struct i915_execbuffer *eb, int out_fence_fd)
> +{
> +	struct sync_file *out_fence = NULL;
> +	struct dma_fence_array *fence_array;
> +	struct dma_fence **fences;
> +	unsigned int i;
> +
> +	GEM_BUG_ON(!intel_context_is_parent(eb->context));
> +
> +	fences = kmalloc_array(eb->num_batches, sizeof(*fences), GFP_KERNEL);
> +	if (!fences)
> +		return ERR_PTR(-ENOMEM);
> +
> +	for_each_batch_create_order(eb, i)
> +		fences[i] = &eb->requests[i]->fence;
> +
> +	fence_array = dma_fence_array_create(eb->num_batches,
> +					     fences,
> +					     eb->context->parallel.fence_context,
> +					     eb->context->parallel.seqno,
> +					     false);
> +	if (!fence_array) {
> +		kfree(fences);
> +		return ERR_PTR(-ENOMEM);
> +	}
> +
> +	/* Move ownership to the dma_fence_array created above */
> +	for_each_batch_create_order(eb, i)
> +		dma_fence_get(fences[i]);
> +
> +	if (out_fence_fd != -1) {
> +		out_fence = sync_file_create(&fence_array->base);
> +		/* sync_file now owns fence_arry, drop creation ref */
> +		dma_fence_put(&fence_array->base);
> +		if (!out_fence)
> +			return ERR_PTR(-ENOMEM);
> +	}
> +
> +	eb->composite_fence = &fence_array->base;
> +
> +	return out_fence;
> +}
> +
> +static struct sync_file *
> +eb_fences_add(struct i915_execbuffer *eb, struct i915_request *rq,
> +	      struct dma_fence *in_fence, int out_fence_fd)
> +{
> +	struct sync_file *out_fence = NULL;
> +	int err;
> +
> +	if (unlikely(eb->gem_context->syncobj)) {
> +		struct dma_fence *fence;
> +
> +		fence = drm_syncobj_fence_get(eb->gem_context->syncobj);
> +		err = i915_request_await_dma_fence(rq, fence);
> +		dma_fence_put(fence);
> +		if (err)
> +			return ERR_PTR(err);
> +	}
> +
> +	if (in_fence) {
> +		if (eb->args->flags & I915_EXEC_FENCE_SUBMIT)
> +			err = i915_request_await_execution(rq, in_fence);
> +		else
> +			err = i915_request_await_dma_fence(rq, in_fence);
> +		if (err < 0)
> +			return ERR_PTR(err);
> +	}
> +
> +	if (eb->fences) {
> +		err = await_fence_array(eb, rq);
> +		if (err)
> +			return ERR_PTR(err);
> +	}
> +
> +	if (intel_context_is_parallel(eb->context)) {
> +		out_fence = eb_composite_fence_create(eb, out_fence_fd);
> +		if (IS_ERR(out_fence))
> +			return ERR_PTR(-ENOMEM);
> +	} else if (out_fence_fd != -1) {
> +		out_fence = sync_file_create(&rq->fence);
> +		if (!out_fence)
> +			return ERR_PTR(-ENOMEM);
> +	}
> +
> +	return out_fence;
> +}
> +
> +static struct intel_context *
> +eb_find_context(struct i915_execbuffer *eb, unsigned int context_number)
> +{
> +	struct intel_context *child;
> +
> +	if (likely(context_number == 0))
> +		return eb->context;
> +
> +	for_each_child(eb->context, child)
> +		if (!--context_number)
> +			return child;
> +
> +	GEM_BUG_ON("Context not found");
> +
> +	return NULL;
> +}
> +
> +static struct sync_file *
> +eb_requests_create(struct i915_execbuffer *eb, struct dma_fence *in_fence,
> +		   int out_fence_fd)
> +{
> +	struct sync_file *out_fence = NULL;
> +	unsigned int i;
> +
> +	for_each_batch_create_order(eb, i) {
> +		/* Allocate a request for this batch buffer nice and early. */
> +		eb->requests[i] = i915_request_create(eb_find_context(eb, i));
> +		if (IS_ERR(eb->requests[i])) {
> +			out_fence = ERR_PTR(PTR_ERR(eb->requests[i]));
> +			eb->requests[i] = NULL;
> +			return out_fence;
> +		}
> +
> +		/*
> +		 * Only the first request added (committed to backend) has to
> +		 * take the in fences into account as all subsequent requests
> +		 * will have fences inserted inbetween them.
> +		 */
> +		if (i + 1 == eb->num_batches) {
> +			out_fence = eb_fences_add(eb, eb->requests[i],
> +						  in_fence, out_fence_fd);
> +			if (IS_ERR(out_fence))
> +				return out_fence;
> +		}
> +
> +		/*
> +		 * Whilst this request exists, batch_obj will be on the
> +		 * active_list, and so will hold the active reference. Only when
> +		 * this request is retired will the batch_obj be moved onto
> +		 * the inactive_list and lose its active reference. Hence we do
> +		 * not need to explicitly hold another reference here.
> +		 */
> +		eb->requests[i]->batch = eb->batches[i]->vma;
> +		if (eb->batch_pool) {
> +			GEM_BUG_ON(intel_context_is_parallel(eb->context));
> +			intel_gt_buffer_pool_mark_active(eb->batch_pool,
> +							 eb->requests[i]);
> +		}
> +	}
> +
> +	return out_fence;
> +}
> +
>   static int
>   i915_gem_do_execbuffer(struct drm_device *dev,
>   		       struct drm_file *file,
> @@ -2813,7 +3156,6 @@ i915_gem_do_execbuffer(struct drm_device *dev,
>   	struct i915_execbuffer eb;
>   	struct dma_fence *in_fence = NULL;
>   	struct sync_file *out_fence = NULL;
> -	struct i915_vma *batch;
>   	int out_fence_fd = -1;
>   	int err;
>   
> @@ -2837,12 +3179,15 @@ i915_gem_do_execbuffer(struct drm_device *dev,
>   
>   	eb.buffer_count = args->buffer_count;
>   	eb.batch_start_offset = args->batch_start_offset;
> -	eb.batch_len = args->batch_len;
>   	eb.trampoline = NULL;
>   
>   	eb.fences = NULL;
>   	eb.num_fences = 0;
>   
> +	memset(eb.requests, 0, sizeof(struct i915_request *) *
> +	       ARRAY_SIZE(eb.requests));
> +	eb.composite_fence = NULL;
> +
>   	eb.batch_flags = 0;
>   	if (args->flags & I915_EXEC_SECURE) {
>   		if (GRAPHICS_VER(i915) >= 11)
> @@ -2926,70 +3271,25 @@ i915_gem_do_execbuffer(struct drm_device *dev,
>   
>   	ww_acquire_done(&eb.ww.ctx);
>   
> -	batch = eb.batch->vma;
> -
> -	/* Allocate a request for this batch buffer nice and early. */
> -	eb.request = i915_request_create(eb.context);
> -	if (IS_ERR(eb.request)) {
> -		err = PTR_ERR(eb.request);
> -		goto err_vma;
> -	}
> -
> -	if (unlikely(eb.gem_context->syncobj)) {
> -		struct dma_fence *fence;
> -
> -		fence = drm_syncobj_fence_get(eb.gem_context->syncobj);
> -		err = i915_request_await_dma_fence(eb.request, fence);
> -		dma_fence_put(fence);
> -		if (err)
> -			goto err_ext;
> -	}
> -
> -	if (in_fence) {
> -		if (args->flags & I915_EXEC_FENCE_SUBMIT)
> -			err = i915_request_await_execution(eb.request,
> -							   in_fence);
> -		else
> -			err = i915_request_await_dma_fence(eb.request,
> -							   in_fence);
> -		if (err < 0)
> -			goto err_request;
> -	}
> -
> -	if (eb.fences) {
> -		err = await_fence_array(&eb);
> -		if (err)
> +	out_fence = eb_requests_create(&eb, in_fence, out_fence_fd);
> +	if (IS_ERR(out_fence)) {
> +		err = PTR_ERR(out_fence);
> +		if (eb.requests[0])
>   			goto err_request;
> +		else
> +			goto err_vma;
>   	}
>   
> -	if (out_fence_fd != -1) {
> -		out_fence = sync_file_create(&eb.request->fence);
> -		if (!out_fence) {
> -			err = -ENOMEM;
> -			goto err_request;
> -		}
> -	}
> -
> -	/*
> -	 * Whilst this request exists, batch_obj will be on the
> -	 * active_list, and so will hold the active reference. Only when this
> -	 * request is retired will the the batch_obj be moved onto the
> -	 * inactive_list and lose its active reference. Hence we do not need
> -	 * to explicitly hold another reference here.
> -	 */
> -	eb.request->batch = batch;
> -	if (eb.batch_pool)
> -		intel_gt_buffer_pool_mark_active(eb.batch_pool, eb.request);
> -
> -	trace_i915_request_queue(eb.request, eb.batch_flags);
> -	err = eb_submit(&eb, batch);
> +	err = eb_submit(&eb);
>   
>   err_request:
> -	i915_request_get(eb.request);
> -	err = eb_request_add(&eb, err);
> +	eb_requests_get(&eb);
> +	err = eb_requests_add(&eb, err);
>   
>   	if (eb.fences)
> -		signal_fence_array(&eb);
> +		signal_fence_array(&eb, eb.composite_fence ?
> +				   eb.composite_fence :
> +				   &eb.requests[0]->fence);
>   
>   	if (out_fence) {
>   		if (err == 0) {
> @@ -3004,10 +3304,15 @@ i915_gem_do_execbuffer(struct drm_device *dev,
>   
>   	if (unlikely(eb.gem_context->syncobj)) {
>   		drm_syncobj_replace_fence(eb.gem_context->syncobj,
> -					  &eb.request->fence);
> +					  eb.composite_fence ?
> +					  eb.composite_fence :
> +					  &eb.requests[0]->fence);
>   	}
>   
> -	i915_request_put(eb.request);
> +	if (!out_fence && eb.composite_fence)
> +		dma_fence_put(eb.composite_fence);
> +
> +	eb_requests_put(&eb);
>   
>   err_vma:
>   	eb_release_vmas(&eb, true);
> diff --git a/drivers/gpu/drm/i915/gt/intel_context.h b/drivers/gpu/drm/i915/gt/intel_context.h
> index 1bc705f98e2a..1781419fa105 100644
> --- a/drivers/gpu/drm/i915/gt/intel_context.h
> +++ b/drivers/gpu/drm/i915/gt/intel_context.h
> @@ -239,7 +239,13 @@ intel_context_timeline_lock(struct intel_context *ce)
>   	struct intel_timeline *tl = ce->timeline;
>   	int err;
>   
> -	err = mutex_lock_interruptible(&tl->mutex);
> +	if (intel_context_is_parent(ce))
> +		err = mutex_lock_interruptible_nested(&tl->mutex, 0);
> +	else if (intel_context_is_child(ce))
> +		err = mutex_lock_interruptible_nested(&tl->mutex,
> +						      ce->parallel.child_index + 1);
> +	else
> +		err = mutex_lock_interruptible(&tl->mutex);
>   	if (err)
>   		return ERR_PTR(err);
>   
> diff --git a/drivers/gpu/drm/i915/gt/intel_context_types.h b/drivers/gpu/drm/i915/gt/intel_context_types.h
> index 95a5b94b4ece..9e0177dc5484 100644
> --- a/drivers/gpu/drm/i915/gt/intel_context_types.h
> +++ b/drivers/gpu/drm/i915/gt/intel_context_types.h
> @@ -248,6 +248,16 @@ struct intel_context {
>   		 * context
>   		 */
>   		struct i915_request *last_rq;
> +		/**
> +		 * @fence_context: fence context composite fence when doing
> +		 * parallel submission
> +		 */
> +		u64 fence_context;
> +		/**
> +		 * @seqno: seqno for composite fence when doing parallel
> +		 * submission
> +		 */
> +		u32 seqno;
>   		/** @number_children: number of children if parent */
>   		u8 number_children;
>   		/** @child_index: index into child_list if child */
> diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
> index ae08a196ba0a..bfafe996e2d2 100644
> --- a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
> +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
> @@ -3099,6 +3099,8 @@ guc_create_parallel(struct intel_engine_cs **engines,
>   		}
>   	}
>   
> +	parent->parallel.fence_context = dma_fence_context_alloc(1);
> +
>   	parent->engine->emit_bb_start =
>   		emit_bb_start_parent_no_preempt_mid_batch;
>   	parent->engine->emit_fini_breadcrumb =
> diff --git a/drivers/gpu/drm/i915/i915_request.h b/drivers/gpu/drm/i915/i915_request.h
> index 8950785e55d6..24db8459376b 100644
> --- a/drivers/gpu/drm/i915/i915_request.h
> +++ b/drivers/gpu/drm/i915/i915_request.h
> @@ -147,6 +147,15 @@ enum {
>   	 * tail.
>   	 */
>   	I915_FENCE_FLAG_SUBMIT_PARALLEL,
> +
> +	/*
> +	 * I915_FENCE_FLAG_SKIP_PARALLEL - request with a context in a
> +	 * parent-child relationship (parallel submission, multi-lrc) that
> +	 * hit an error while generating requests in the execbuf IOCTL.
> +	 * Indicates this request should be skipped as another request in
> +	 * submission / relationship encoutered an error.
> +	 */
> +	I915_FENCE_FLAG_SKIP_PARALLEL,
>   };
>   
>   /**
> diff --git a/drivers/gpu/drm/i915/i915_vma.c b/drivers/gpu/drm/i915/i915_vma.c
> index 4b7fc4647e46..90546fa58fc1 100644
> --- a/drivers/gpu/drm/i915/i915_vma.c
> +++ b/drivers/gpu/drm/i915/i915_vma.c
> @@ -1234,9 +1234,10 @@ int __i915_vma_move_to_active(struct i915_vma *vma, struct i915_request *rq)
>   	return i915_active_add_request(&vma->active, rq);
>   }
>   
> -int i915_vma_move_to_active(struct i915_vma *vma,
> -			    struct i915_request *rq,
> -			    unsigned int flags)
> +int _i915_vma_move_to_active(struct i915_vma *vma,
> +			     struct i915_request *rq,
> +			     struct dma_fence *fence,
> +			     unsigned int flags)
>   {
>   	struct drm_i915_gem_object *obj = vma->obj;
>   	int err;
> @@ -1257,9 +1258,11 @@ int i915_vma_move_to_active(struct i915_vma *vma,
>   			intel_frontbuffer_put(front);
>   		}
>   
> -		dma_resv_add_excl_fence(vma->resv, &rq->fence);
> -		obj->write_domain = I915_GEM_DOMAIN_RENDER;
> -		obj->read_domains = 0;
> +		if (fence) {
> +			dma_resv_add_excl_fence(vma->resv, fence);
> +			obj->write_domain = I915_GEM_DOMAIN_RENDER;
> +			obj->read_domains = 0;
> +		}
>   	} else {
>   		if (!(flags & __EXEC_OBJECT_NO_RESERVE)) {
>   			err = dma_resv_reserve_shared(vma->resv, 1);
> @@ -1267,8 +1270,10 @@ int i915_vma_move_to_active(struct i915_vma *vma,
>   				return err;
>   		}
>   
> -		dma_resv_add_shared_fence(vma->resv, &rq->fence);
> -		obj->write_domain = 0;
> +		if (fence) {
> +			dma_resv_add_shared_fence(vma->resv, fence);
> +			obj->write_domain = 0;
> +		}
>   	}
>   
>   	if (flags & EXEC_OBJECT_NEEDS_FENCE && vma->fence)
> diff --git a/drivers/gpu/drm/i915/i915_vma.h b/drivers/gpu/drm/i915/i915_vma.h
> index ed69f66c7ab0..648dbe744c96 100644
> --- a/drivers/gpu/drm/i915/i915_vma.h
> +++ b/drivers/gpu/drm/i915/i915_vma.h
> @@ -57,9 +57,16 @@ static inline bool i915_vma_is_active(const struct i915_vma *vma)
>   
>   int __must_check __i915_vma_move_to_active(struct i915_vma *vma,
>   					   struct i915_request *rq);
> -int __must_check i915_vma_move_to_active(struct i915_vma *vma,
> -					 struct i915_request *rq,
> -					 unsigned int flags);
> +int __must_check _i915_vma_move_to_active(struct i915_vma *vma,
> +					  struct i915_request *rq,
> +					  struct dma_fence *fence,
> +					  unsigned int flags);
> +static inline int __must_check
> +i915_vma_move_to_active(struct i915_vma *vma, struct i915_request *rq,
> +			unsigned int flags)
> +{
> +	return _i915_vma_move_to_active(vma, rq, &rq->fence, flags);
> +}
>   
>   #define __i915_vma_flags(v) ((unsigned long *)&(v)->flags.counter)
>

Matthew Brost Oct. 14, 2021, 3:34 p.m. UTC | #2

On Wed, Oct 13, 2021 at 05:55:51PM -0700, John Harrison wrote:
> On 10/13/2021 13:42, Matthew Brost wrote:
> > Allow multiple batch buffers to be submitted in a single execbuf IOCTL
> > after a context has been configured with the 'set_parallel' extension.
> > The number batches is implicit based on the contexts configuration.
> > 
> > This is implemented with a series of loops. First a loop is used to find
> > all the batches, a loop to pin all the HW contexts, a loop to create all
> > the requests, a loop to submit (emit BB start, etc...) all the requests,
> > a loop to tie the requests to the VMAs they touch, and finally a loop to
> > commit the requests to the backend.
> > 
> > A composite fence is also created for the generated requests to return
> > to the user and to stick in dma resv slots.
> > 
> > No behavior from the existing IOCTL should be changed aside from when
> > throttling because the ring for a context is full. In this situation,
> > i915 will now wait while holding the object locks. This change was done
> > because the code is much simpler to wait while holding the locks and we
> > believe there isn't a huge benefit of dropping these locks. If this
> > proves false we can restructure the code to drop the locks during the
> > wait.
> > 
> > IGT: https://patchwork.freedesktop.org/patch/447008/?series=93071&rev=1
> > media UMD: https://github.com/intel/media-driver/pull/1252
> > 
> > v2:
> >   (Matthew Brost)
> >    - Return proper error value if i915_request_create fails
> > v3:
> >   (John Harrison)
> >    - Add comment explaining create / add order loops + locking
> >    - Update commit message explaining different in IOCTL behavior
> >    - Line wrap some comments
> >    - eb_add_request returns void
> >    - Return -EINVAL rather triggering BUG_ON if cmd parser used
> >   (Checkpatch)
> >    - Check eb->batch_len[*current_batch]
> > v4:
> >   (CI)
> >    - Set batch len if passed if via execbuf args
> >    - Call __i915_request_skip after __i915_request_commit
> >   (Kernel test robot)
> >    - Initialize rq to NULL in eb_pin_timeline
> > 
> > Signed-off-by: Matthew Brost <[e-mail]>
> > ---
> >   .../gpu/drm/i915/gem/i915_gem_execbuffer.c    | 783 ++++++++++++------
> >   drivers/gpu/drm/i915/gt/intel_context.h       |   8 +-
> >   drivers/gpu/drm/i915/gt/intel_context_types.h |  10 +
> >   .../gpu/drm/i915/gt/uc/intel_guc_submission.c |   2 +
> >   drivers/gpu/drm/i915/i915_request.h           |   9 +
> >   drivers/gpu/drm/i915/i915_vma.c               |  21 +-
> >   drivers/gpu/drm/i915/i915_vma.h               |  13 +-
> >   7 files changed, 595 insertions(+), 251 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c
> > index c75afc8784e3..6509c9d8c298 100644
> > --- a/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c
> > +++ b/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c
> > @@ -246,17 +246,25 @@ struct i915_execbuffer {
> >   	struct drm_i915_gem_exec_object2 *exec; /** ioctl execobj[] */
> >   	struct eb_vma *vma;
> > -	struct intel_engine_cs *engine; /** engine to queue the request to */
> > +	struct intel_gt *gt; /* gt for the execbuf */
> >   	struct intel_context *context; /* logical state for the request */
> >   	struct i915_gem_context *gem_context; /** caller's context */
> > -	struct i915_request *request; /** our request to build */
> > -	struct eb_vma *batch; /** identity of the batch obj/vma */
> > +	/** our requests to build */
> > +	struct i915_request *requests[MAX_ENGINE_INSTANCE + 1];
> > +	/** identity of the batch obj/vma */
> > +	struct eb_vma *batches[MAX_ENGINE_INSTANCE + 1];
> >   	struct i915_vma *trampoline; /** trampoline used for chaining */
> > +	/** used for excl fence in dma_resv objects when > 1 BB submitted */
> > +	struct dma_fence *composite_fence;
> > +
> >   	/** actual size of execobj[] as we may extend it for the cmdparser */
> >   	unsigned int buffer_count;
> > +	/* number of batches in execbuf IOCTL */
> > +	unsigned int num_batches;
> > +
> >   	/** list of vma not yet bound during reservation phase */
> >   	struct list_head unbound;
> > @@ -283,7 +291,8 @@ struct i915_execbuffer {
> >   	u64 invalid_flags; /** Set of execobj.flags that are invalid */
> > -	u64 batch_len; /** Length of batch within object */
> > +	/** Length of batch within object */
> > +	u64 batch_len[MAX_ENGINE_INSTANCE + 1];
> >   	u32 batch_start_offset; /** Location within object of batch */
> >   	u32 batch_flags; /** Flags composed for emit_bb_start() */
> >   	struct intel_gt_buffer_pool_node *batch_pool; /** pool node for batch buffer */
> > @@ -301,14 +310,13 @@ struct i915_execbuffer {
> >   };
> >   static int eb_parse(struct i915_execbuffer *eb);
> > -static struct i915_request *eb_pin_engine(struct i915_execbuffer *eb,
> > -					  bool throttle);
> > +static int eb_pin_engine(struct i915_execbuffer *eb, bool throttle);
> >   static void eb_unpin_engine(struct i915_execbuffer *eb);
> >   static inline bool eb_use_cmdparser(const struct i915_execbuffer *eb)
> >   {
> > -	return intel_engine_requires_cmd_parser(eb->engine) ||
> > -		(intel_engine_using_cmd_parser(eb->engine) &&
> > +	return intel_engine_requires_cmd_parser(eb->context->engine) ||
> > +		(intel_engine_using_cmd_parser(eb->context->engine) &&
> >   		 eb->args->batch_len);
> >   }
> > @@ -546,11 +554,21 @@ eb_validate_vma(struct i915_execbuffer *eb,
> >   	return 0;
> >   }
> > -static void
> > +static inline bool
> > +is_batch_buffer(struct i915_execbuffer *eb, unsigned int buffer_idx)
> > +{
> > +	return eb->args->flags & I915_EXEC_BATCH_FIRST ?
> > +		buffer_idx < eb->num_batches :
> > +		buffer_idx >= eb->args->buffer_count - eb->num_batches;
> > +}
> > +
> > +static int
> >   eb_add_vma(struct i915_execbuffer *eb,
> > -	   unsigned int i, unsigned batch_idx,
> > +	   unsigned int *current_batch,
> > +	   unsigned int i,
> >   	   struct i915_vma *vma)
> >   {
> > +	struct drm_i915_private *i915 = eb->i915;
> >   	struct drm_i915_gem_exec_object2 *entry = &eb->exec[i];
> >   	struct eb_vma *ev = &eb->vma[i];
> > @@ -577,15 +595,43 @@ eb_add_vma(struct i915_execbuffer *eb,
> >   	 * Note that actual hangs have only been observed on gen7, but for
> >   	 * paranoia do it everywhere.
> >   	 */
> > -	if (i == batch_idx) {
> > +	if (is_batch_buffer(eb, i)) {
> >   		if (entry->relocation_count &&
> >   		    !(ev->flags & EXEC_OBJECT_PINNED))
> >   			ev->flags |= __EXEC_OBJECT_NEEDS_BIAS;
> >   		if (eb->reloc_cache.has_fence)
> >   			ev->flags |= EXEC_OBJECT_NEEDS_FENCE;
> > -		eb->batch = ev;
> > +		eb->batches[*current_batch] = ev;
> > +
> > +		if (unlikely(ev->flags & EXEC_OBJECT_WRITE)) {
> > +			drm_dbg(&i915->drm,
> > +				"Attempting to use self-modifying batch buffer\n");
> > +			return -EINVAL;
> > +		}
> > +
> > +		if (range_overflows_t(u64,
> > +				      eb->batch_start_offset,
> > +				      eb->args->batch_len,
> > +				      ev->vma->size)) {
> > +			drm_dbg(&i915->drm, "Attempting to use out-of-bounds batch\n");
> > +			return -EINVAL;
> > +		}
> > +
> > +		if (eb->args->batch_len == 0)
> > +			eb->batch_len[*current_batch] = ev->vma->size -
> > +				eb->batch_start_offset;
> > +		else
> > +			eb->batch_len[*current_batch] = eb->args->batch_len;
> > +		if (unlikely(eb->batch_len[*current_batch] == 0)) { /* impossible! */
> > +			drm_dbg(&i915->drm, "Invalid batch length\n");
> > +			return -EINVAL;
> > +		}
> > +
> > +		++*current_batch;
> >   	}
> > +
> > +	return 0;
> >   }
> >   static inline int use_cpu_reloc(const struct reloc_cache *cache,
> > @@ -729,14 +775,6 @@ static int eb_reserve(struct i915_execbuffer *eb)
> >   	} while (1);
> >   }
> > -static unsigned int eb_batch_index(const struct i915_execbuffer *eb)
> > -{
> > -	if (eb->args->flags & I915_EXEC_BATCH_FIRST)
> > -		return 0;
> > -	else
> > -		return eb->buffer_count - 1;
> > -}
> > -
> >   static int eb_select_context(struct i915_execbuffer *eb)
> >   {
> >   	struct i915_gem_context *ctx;
> > @@ -857,9 +895,7 @@ static struct i915_vma *eb_lookup_vma(struct i915_execbuffer *eb, u32 handle)
> >   static int eb_lookup_vmas(struct i915_execbuffer *eb)
> >   {
> > -	struct drm_i915_private *i915 = eb->i915;
> > -	unsigned int batch = eb_batch_index(eb);
> > -	unsigned int i;
> > +	unsigned int i, current_batch = 0;
> >   	int err = 0;
> >   	INIT_LIST_HEAD(&eb->relocs);
> > @@ -879,7 +915,9 @@ static int eb_lookup_vmas(struct i915_execbuffer *eb)
> >   			goto err;
> >   		}
> > -		eb_add_vma(eb, i, batch, vma);
> > +		err = eb_add_vma(eb, &current_batch, i, vma);
> > +		if (err)
> > +			return err;
> >   		if (i915_gem_object_is_userptr(vma->obj)) {
> >   			err = i915_gem_object_userptr_submit_init(vma->obj);
> > @@ -902,26 +940,6 @@ static int eb_lookup_vmas(struct i915_execbuffer *eb)
> >   		}
> >   	}
> > -	if (unlikely(eb->batch->flags & EXEC_OBJECT_WRITE)) {
> > -		drm_dbg(&i915->drm,
> > -			"Attempting to use self-modifying batch buffer\n");
> > -		return -EINVAL;
> > -	}
> > -
> > -	if (range_overflows_t(u64,
> > -			      eb->batch_start_offset, eb->batch_len,
> > -			      eb->batch->vma->size)) {
> > -		drm_dbg(&i915->drm, "Attempting to use out-of-bounds batch\n");
> > -		return -EINVAL;
> > -	}
> > -
> > -	if (eb->batch_len == 0)
> > -		eb->batch_len = eb->batch->vma->size - eb->batch_start_offset;
> > -	if (unlikely(eb->batch_len == 0)) { /* impossible! */
> > -		drm_dbg(&i915->drm, "Invalid batch length\n");
> > -		return -EINVAL;
> > -	}
> > -
> >   	return 0;
> >   err:
> > @@ -1654,8 +1672,7 @@ static int eb_reinit_userptr(struct i915_execbuffer *eb)
> >   	return 0;
> >   }
> > -static noinline int eb_relocate_parse_slow(struct i915_execbuffer *eb,
> > -					   struct i915_request *rq)
> > +static noinline int eb_relocate_parse_slow(struct i915_execbuffer *eb)
> >   {
> >   	bool have_copy = false;
> >   	struct eb_vma *ev;
> > @@ -1671,21 +1688,6 @@ static noinline int eb_relocate_parse_slow(struct i915_execbuffer *eb,
> >   	eb_release_vmas(eb, false);
> >   	i915_gem_ww_ctx_fini(&eb->ww);
> > -	if (rq) {
> > -		/* nonblocking is always false */
> > -		if (i915_request_wait(rq, I915_WAIT_INTERRUPTIBLE,
> > -				      MAX_SCHEDULE_TIMEOUT) < 0) {
> > -			i915_request_put(rq);
> > -			rq = NULL;
> > -
> > -			err = -EINTR;
> > -			goto err_relock;
> > -		}
> > -
> > -		i915_request_put(rq);
> > -		rq = NULL;
> > -	}
> > -
> >   	/*
> >   	 * We take 3 passes through the slowpatch.
> >   	 *
> > @@ -1712,28 +1714,21 @@ static noinline int eb_relocate_parse_slow(struct i915_execbuffer *eb,
> >   	if (!err)
> >   		err = eb_reinit_userptr(eb);
> > -err_relock:
> >   	i915_gem_ww_ctx_init(&eb->ww, true);
> >   	if (err)
> >   		goto out;
> >   	/* reacquire the objects */
> >   repeat_validate:
> > -	rq = eb_pin_engine(eb, false);
> > -	if (IS_ERR(rq)) {
> > -		err = PTR_ERR(rq);
> > -		rq = NULL;
> > +	err = eb_pin_engine(eb, false);
> > +	if (err)
> >   		goto err;
> > -	}
> > -
> > -	/* We didn't throttle, should be NULL */
> > -	GEM_WARN_ON(rq);
> >   	err = eb_validate_vmas(eb);
> >   	if (err)
> >   		goto err;
> > -	GEM_BUG_ON(!eb->batch);
> > +	GEM_BUG_ON(!eb->batches[0]);
> >   	list_for_each_entry(ev, &eb->relocs, reloc_link) {
> >   		if (!have_copy) {
> > @@ -1797,46 +1792,23 @@ static noinline int eb_relocate_parse_slow(struct i915_execbuffer *eb,
> >   		}
> >   	}
> > -	if (rq)
> > -		i915_request_put(rq);
> > -
> >   	return err;
> >   }
> >   static int eb_relocate_parse(struct i915_execbuffer *eb)
> >   {
> >   	int err;
> > -	struct i915_request *rq = NULL;
> >   	bool throttle = true;
> >   retry:
> > -	rq = eb_pin_engine(eb, throttle);
> > -	if (IS_ERR(rq)) {
> > -		err = PTR_ERR(rq);
> > -		rq = NULL;
> > +	err = eb_pin_engine(eb, throttle);
> > +	if (err) {
> >   		if (err != -EDEADLK)
> >   			return err;
> >   		goto err;
> >   	}
> > -	if (rq) {
> > -		bool nonblock = eb->file->filp->f_flags & O_NONBLOCK;
> > -
> > -		/* Need to drop all locks now for throttling, take slowpath */
> > -		err = i915_request_wait(rq, I915_WAIT_INTERRUPTIBLE, 0);
> > -		if (err == -ETIME) {
> > -			if (nonblock) {
> > -				err = -EWOULDBLOCK;
> > -				i915_request_put(rq);
> > -				goto err;
> > -			}
> > -			goto slow;
> > -		}
> > -		i915_request_put(rq);
> > -		rq = NULL;
> > -	}
> > -
> >   	/* only throttle once, even if we didn't need to throttle */
> >   	throttle = false;
> > @@ -1876,7 +1848,7 @@ static int eb_relocate_parse(struct i915_execbuffer *eb)
> >   	return err;
> >   slow:
> > -	err = eb_relocate_parse_slow(eb, rq);
> > +	err = eb_relocate_parse_slow(eb);
> >   	if (err)
> >   		/*
> >   		 * If the user expects the execobject.offset and
> > @@ -1890,11 +1862,40 @@ static int eb_relocate_parse(struct i915_execbuffer *eb)
> >   	return err;
> >   }
> > +/*
> > + * Using two helper loops for the order of which requests / batches are created
> > + * and added the to backend. Requests are created in order from the parent to
> > + * the last child. Requests are add in the reverse order, from the last child to
> are add -> are added
> 

Yep.

> > + * parent. This is down from locking reasons as the timeline lock is acquired
> down from -> done for?
>

And yep. Will fix.

Matt

> John.
> 
> > + * during request creation and released when the request is added to the
> > + * backend. To make lockdep happy (see intel_context_timeline_lock) this must be
> > + * the ordering.
> > + */
> > +#define for_each_batch_create_order(_eb, _i) \
> > +	for ((_i) = 0; (_i) < (_eb)->num_batches; ++(_i))
> > +#define for_each_batch_add_order(_eb, _i) \
> > +	BUILD_BUG_ON(!typecheck(int, _i)); \
> > +	for ((_i) = (_eb)->num_batches - 1; (_i) >= 0; --(_i))
> > +
> > +static struct i915_request *
> > +eb_find_first_request_added(struct i915_execbuffer *eb)
> > +{
> > +	int i;
> > +
> > +	for_each_batch_add_order(eb, i)
> > +		if (eb->requests[i])
> > +			return eb->requests[i];
> > +
> > +	GEM_BUG_ON("Request not found");
> > +
> > +	return NULL;
> > +}
> > +
> >   static int eb_move_to_gpu(struct i915_execbuffer *eb)
> >   {
> >   	const unsigned int count = eb->buffer_count;
> >   	unsigned int i = count;
> > -	int err = 0;
> > +	int err = 0, j;
> >   	while (i--) {
> >   		struct eb_vma *ev = &eb->vma[i];
> > @@ -1907,11 +1908,17 @@ static int eb_move_to_gpu(struct i915_execbuffer *eb)
> >   		if (flags & EXEC_OBJECT_CAPTURE) {
> >   			struct i915_capture_list *capture;
> > -			capture = kmalloc(sizeof(*capture), GFP_KERNEL);
> > -			if (capture) {
> > -				capture->next = eb->request->capture_list;
> > -				capture->vma = vma;
> > -				eb->request->capture_list = capture;
> > +			for_each_batch_create_order(eb, j) {
> > +				if (!eb->requests[j])
> > +					break;
> > +
> > +				capture = kmalloc(sizeof(*capture), GFP_KERNEL);
> > +				if (capture) {
> > +					capture->next =
> > +						eb->requests[j]->capture_list;
> > +					capture->vma = vma;
> > +					eb->requests[j]->capture_list = capture;
> > +				}
> >   			}
> >   		}
> > @@ -1932,14 +1939,26 @@ static int eb_move_to_gpu(struct i915_execbuffer *eb)
> >   				flags &= ~EXEC_OBJECT_ASYNC;
> >   		}
> > +		/* We only need to await on the first request */
> >   		if (err == 0 && !(flags & EXEC_OBJECT_ASYNC)) {
> >   			err = i915_request_await_object
> > -				(eb->request, obj, flags & EXEC_OBJECT_WRITE);
> > +				(eb_find_first_request_added(eb), obj,
> > +				 flags & EXEC_OBJECT_WRITE);
> >   		}
> > -		if (err == 0)
> > -			err = i915_vma_move_to_active(vma, eb->request,
> > -						      flags | __EXEC_OBJECT_NO_RESERVE);
> > +		for_each_batch_add_order(eb, j) {
> > +			if (err)
> > +				break;
> > +			if (!eb->requests[j])
> > +				continue;
> > +
> > +			err = _i915_vma_move_to_active(vma, eb->requests[j],
> > +						       j ? NULL :
> > +						       eb->composite_fence ?
> > +						       eb->composite_fence :
> > +						       &eb->requests[j]->fence,
> > +						       flags | __EXEC_OBJECT_NO_RESERVE);
> > +		}
> >   	}
> >   #ifdef CONFIG_MMU_NOTIFIER
> > @@ -1970,11 +1989,16 @@ static int eb_move_to_gpu(struct i915_execbuffer *eb)
> >   		goto err_skip;
> >   	/* Unconditionally flush any chipset caches (for streaming writes). */
> > -	intel_gt_chipset_flush(eb->engine->gt);
> > +	intel_gt_chipset_flush(eb->gt);
> >   	return 0;
> >   err_skip:
> > -	i915_request_set_error_once(eb->request, err);
> > +	for_each_batch_create_order(eb, j) {
> > +		if (!eb->requests[j])
> > +			break;
> > +
> > +		i915_request_set_error_once(eb->requests[j], err);
> > +	}
> >   	return err;
> >   }
> > @@ -2069,14 +2093,17 @@ static int eb_parse(struct i915_execbuffer *eb)
> >   	int err;
> >   	if (!eb_use_cmdparser(eb)) {
> > -		batch = eb_dispatch_secure(eb, eb->batch->vma);
> > +		batch = eb_dispatch_secure(eb, eb->batches[0]->vma);
> >   		if (IS_ERR(batch))
> >   			return PTR_ERR(batch);
> >   		goto secure_batch;
> >   	}
> > -	len = eb->batch_len;
> > +	if (intel_context_is_parallel(eb->context))
> > +		return -EINVAL;
> > +
> > +	len = eb->batch_len[0];
> >   	if (!CMDPARSER_USES_GGTT(eb->i915)) {
> >   		/*
> >   		 * ppGTT backed shadow buffers must be mapped RO, to prevent
> > @@ -2090,11 +2117,11 @@ static int eb_parse(struct i915_execbuffer *eb)
> >   	} else {
> >   		len += I915_CMD_PARSER_TRAMPOLINE_SIZE;
> >   	}
> > -	if (unlikely(len < eb->batch_len)) /* last paranoid check of overflow */
> > +	if (unlikely(len < eb->batch_len[0])) /* last paranoid check of overflow */
> >   		return -EINVAL;
> >   	if (!pool) {
> > -		pool = intel_gt_get_buffer_pool(eb->engine->gt, len,
> > +		pool = intel_gt_get_buffer_pool(eb->gt, len,
> >   						I915_MAP_WB);
> >   		if (IS_ERR(pool))
> >   			return PTR_ERR(pool);
> > @@ -2119,7 +2146,7 @@ static int eb_parse(struct i915_execbuffer *eb)
> >   		trampoline = shadow;
> >   		shadow = shadow_batch_pin(eb, pool->obj,
> > -					  &eb->engine->gt->ggtt->vm,
> > +					  &eb->gt->ggtt->vm,
> >   					  PIN_GLOBAL);
> >   		if (IS_ERR(shadow)) {
> >   			err = PTR_ERR(shadow);
> > @@ -2141,26 +2168,29 @@ static int eb_parse(struct i915_execbuffer *eb)
> >   	if (err)
> >   		goto err_trampoline;
> > -	err = intel_engine_cmd_parser(eb->engine,
> > -				      eb->batch->vma,
> > +	err = intel_engine_cmd_parser(eb->context->engine,
> > +				      eb->batches[0]->vma,
> >   				      eb->batch_start_offset,
> > -				      eb->batch_len,
> > +				      eb->batch_len[0],
> >   				      shadow, trampoline);
> >   	if (err)
> >   		goto err_unpin_batch;
> > -	eb->batch = &eb->vma[eb->buffer_count++];
> > -	eb->batch->vma = i915_vma_get(shadow);
> > -	eb->batch->flags = __EXEC_OBJECT_HAS_PIN;
> > +	eb->batches[0] = &eb->vma[eb->buffer_count++];
> > +	eb->batches[0]->vma = i915_vma_get(shadow);
> > +	eb->batches[0]->flags = __EXEC_OBJECT_HAS_PIN;
> >   	eb->trampoline = trampoline;
> >   	eb->batch_start_offset = 0;
> >   secure_batch:
> >   	if (batch) {
> > -		eb->batch = &eb->vma[eb->buffer_count++];
> > -		eb->batch->flags = __EXEC_OBJECT_HAS_PIN;
> > -		eb->batch->vma = i915_vma_get(batch);
> > +		if (intel_context_is_parallel(eb->context))
> > +			return -EINVAL;
> > +
> > +		eb->batches[0] = &eb->vma[eb->buffer_count++];
> > +		eb->batches[0]->flags = __EXEC_OBJECT_HAS_PIN;
> > +		eb->batches[0]->vma = i915_vma_get(batch);
> >   	}
> >   	return 0;
> > @@ -2176,19 +2206,18 @@ static int eb_parse(struct i915_execbuffer *eb)
> >   	return err;
> >   }
> > -static int eb_submit(struct i915_execbuffer *eb, struct i915_vma *batch)
> > +static int eb_request_submit(struct i915_execbuffer *eb,
> > +			     struct i915_request *rq,
> > +			     struct i915_vma *batch,
> > +			     u64 batch_len)
> >   {
> >   	int err;
> > -	if (intel_context_nopreempt(eb->context))
> > -		__set_bit(I915_FENCE_FLAG_NOPREEMPT, &eb->request->fence.flags);
> > -
> > -	err = eb_move_to_gpu(eb);
> > -	if (err)
> > -		return err;
> > +	if (intel_context_nopreempt(rq->context))
> > +		__set_bit(I915_FENCE_FLAG_NOPREEMPT, &rq->fence.flags);
> >   	if (eb->args->flags & I915_EXEC_GEN7_SOL_RESET) {
> > -		err = i915_reset_gen7_sol_offsets(eb->request);
> > +		err = i915_reset_gen7_sol_offsets(rq);
> >   		if (err)
> >   			return err;
> >   	}
> > @@ -2199,26 +2228,26 @@ static int eb_submit(struct i915_execbuffer *eb, struct i915_vma *batch)
> >   	 * allows us to determine if the batch is still waiting on the GPU
> >   	 * or actually running by checking the breadcrumb.
> >   	 */
> > -	if (eb->engine->emit_init_breadcrumb) {
> > -		err = eb->engine->emit_init_breadcrumb(eb->request);
> > +	if (rq->context->engine->emit_init_breadcrumb) {
> > +		err = rq->context->engine->emit_init_breadcrumb(rq);
> >   		if (err)
> >   			return err;
> >   	}
> > -	err = eb->engine->emit_bb_start(eb->request,
> > -					batch->node.start +
> > -					eb->batch_start_offset,
> > -					eb->batch_len,
> > -					eb->batch_flags);
> > +	err = rq->context->engine->emit_bb_start(rq,
> > +						 batch->node.start +
> > +						 eb->batch_start_offset,
> > +						 batch_len,
> > +						 eb->batch_flags);
> >   	if (err)
> >   		return err;
> >   	if (eb->trampoline) {
> > +		GEM_BUG_ON(intel_context_is_parallel(rq->context));
> >   		GEM_BUG_ON(eb->batch_start_offset);
> > -		err = eb->engine->emit_bb_start(eb->request,
> > -						eb->trampoline->node.start +
> > -						eb->batch_len,
> > -						0, 0);
> > +		err = rq->context->engine->emit_bb_start(rq,
> > +							 eb->trampoline->node.start +
> > +							 batch_len, 0, 0);
> >   		if (err)
> >   			return err;
> >   	}
> > @@ -2226,6 +2255,27 @@ static int eb_submit(struct i915_execbuffer *eb, struct i915_vma *batch)
> >   	return 0;
> >   }
> > +static int eb_submit(struct i915_execbuffer *eb)
> > +{
> > +	unsigned int i;
> > +	int err;
> > +
> > +	err = eb_move_to_gpu(eb);
> > +
> > +	for_each_batch_create_order(eb, i) {
> > +		if (!eb->requests[i])
> > +			break;
> > +
> > +		trace_i915_request_queue(eb->requests[i], eb->batch_flags);
> > +		if (!err)
> > +			err = eb_request_submit(eb, eb->requests[i],
> > +						eb->batches[i]->vma,
> > +						eb->batch_len[i]);
> > +	}
> > +
> > +	return err;
> > +}
> > +
> >   static int num_vcs_engines(const struct drm_i915_private *i915)
> >   {
> >   	return hweight_long(VDBOX_MASK(&i915->gt));
> > @@ -2291,26 +2341,11 @@ static struct i915_request *eb_throttle(struct i915_execbuffer *eb, struct intel
> >   	return i915_request_get(rq);
> >   }
> > -static struct i915_request *eb_pin_engine(struct i915_execbuffer *eb, bool throttle)
> > +static int eb_pin_timeline(struct i915_execbuffer *eb, struct intel_context *ce,
> > +			   bool throttle)
> >   {
> > -	struct intel_context *ce = eb->context;
> >   	struct intel_timeline *tl;
> >   	struct i915_request *rq = NULL;
> > -	int err;
> > -
> > -	GEM_BUG_ON(eb->args->flags & __EXEC_ENGINE_PINNED);
> > -
> > -	if (unlikely(intel_context_is_banned(ce)))
> > -		return ERR_PTR(-EIO);
> > -
> > -	/*
> > -	 * Pinning the contexts may generate requests in order to acquire
> > -	 * GGTT space, so do this first before we reserve a seqno for
> > -	 * ourselves.
> > -	 */
> > -	err = intel_context_pin_ww(ce, &eb->ww);
> > -	if (err)
> > -		return ERR_PTR(err);
> >   	/*
> >   	 * Take a local wakeref for preparing to dispatch the execbuf as
> > @@ -2321,33 +2356,108 @@ static struct i915_request *eb_pin_engine(struct i915_execbuffer *eb, bool throt
> >   	 * taken on the engine, and the parent device.
> >   	 */
> >   	tl = intel_context_timeline_lock(ce);
> > -	if (IS_ERR(tl)) {
> > -		intel_context_unpin(ce);
> > -		return ERR_CAST(tl);
> > -	}
> > +	if (IS_ERR(tl))
> > +		return PTR_ERR(tl);
> >   	intel_context_enter(ce);
> >   	if (throttle)
> >   		rq = eb_throttle(eb, ce);
> >   	intel_context_timeline_unlock(tl);
> > +	if (rq) {
> > +		bool nonblock = eb->file->filp->f_flags & O_NONBLOCK;
> > +		long timeout = nonblock ? 0 : MAX_SCHEDULE_TIMEOUT;
> > +
> > +		if (i915_request_wait(rq, I915_WAIT_INTERRUPTIBLE,
> > +				      timeout) < 0) {
> > +			i915_request_put(rq);
> > +
> > +			tl = intel_context_timeline_lock(ce);
> > +			intel_context_exit(ce);
> > +			intel_context_timeline_unlock(tl);
> > +
> > +			if (nonblock)
> > +				return -EWOULDBLOCK;
> > +			else
> > +				return -EINTR;
> > +		}
> > +		i915_request_put(rq);
> > +	}
> > +
> > +	return 0;
> > +}
> > +
> > +static int eb_pin_engine(struct i915_execbuffer *eb, bool throttle)
> > +{
> > +	struct intel_context *ce = eb->context, *child;
> > +	int err;
> > +	int i = 0, j = 0;
> > +
> > +	GEM_BUG_ON(eb->args->flags & __EXEC_ENGINE_PINNED);
> > +
> > +	if (unlikely(intel_context_is_banned(ce)))
> > +		return -EIO;
> > +
> > +	/*
> > +	 * Pinning the contexts may generate requests in order to acquire
> > +	 * GGTT space, so do this first before we reserve a seqno for
> > +	 * ourselves.
> > +	 */
> > +	err = intel_context_pin_ww(ce, &eb->ww);
> > +	if (err)
> > +		return err;
> > +	for_each_child(ce, child) {
> > +		err = intel_context_pin_ww(child, &eb->ww);
> > +		GEM_BUG_ON(err);	/* perma-pinned should incr a counter */
> > +	}
> > +
> > +	for_each_child(ce, child) {
> > +		err = eb_pin_timeline(eb, child, throttle);
> > +		if (err)
> > +			goto unwind;
> > +		++i;
> > +	}
> > +	err = eb_pin_timeline(eb, ce, throttle);
> > +	if (err)
> > +		goto unwind;
> > +
> >   	eb->args->flags |= __EXEC_ENGINE_PINNED;
> > -	return rq;
> > +	return 0;
> > +
> > +unwind:
> > +	for_each_child(ce, child) {
> > +		if (j++ < i) {
> > +			mutex_lock(&child->timeline->mutex);
> > +			intel_context_exit(child);
> > +			mutex_unlock(&child->timeline->mutex);
> > +		}
> > +	}
> > +	for_each_child(ce, child)
> > +		intel_context_unpin(child);
> > +	intel_context_unpin(ce);
> > +	return err;
> >   }
> >   static void eb_unpin_engine(struct i915_execbuffer *eb)
> >   {
> > -	struct intel_context *ce = eb->context;
> > -	struct intel_timeline *tl = ce->timeline;
> > +	struct intel_context *ce = eb->context, *child;
> >   	if (!(eb->args->flags & __EXEC_ENGINE_PINNED))
> >   		return;
> >   	eb->args->flags &= ~__EXEC_ENGINE_PINNED;
> > -	mutex_lock(&tl->mutex);
> > +	for_each_child(ce, child) {
> > +		mutex_lock(&child->timeline->mutex);
> > +		intel_context_exit(child);
> > +		mutex_unlock(&child->timeline->mutex);
> > +
> > +		intel_context_unpin(child);
> > +	}
> > +
> > +	mutex_lock(&ce->timeline->mutex);
> >   	intel_context_exit(ce);
> > -	mutex_unlock(&tl->mutex);
> > +	mutex_unlock(&ce->timeline->mutex);
> >   	intel_context_unpin(ce);
> >   }
> > @@ -2398,7 +2508,7 @@ eb_select_legacy_ring(struct i915_execbuffer *eb)
> >   static int
> >   eb_select_engine(struct i915_execbuffer *eb)
> >   {
> > -	struct intel_context *ce;
> > +	struct intel_context *ce, *child;
> >   	unsigned int idx;
> >   	int err;
> > @@ -2411,6 +2521,20 @@ eb_select_engine(struct i915_execbuffer *eb)
> >   	if (IS_ERR(ce))
> >   		return PTR_ERR(ce);
> > +	if (intel_context_is_parallel(ce)) {
> > +		if (eb->buffer_count < ce->parallel.number_children + 1) {
> > +			intel_context_put(ce);
> > +			return -EINVAL;
> > +		}
> > +		if (eb->batch_start_offset || eb->args->batch_len) {
> > +			intel_context_put(ce);
> > +			return -EINVAL;
> > +		}
> > +	}
> > +	eb->num_batches = ce->parallel.number_children + 1;
> > +
> > +	for_each_child(ce, child)
> > +		intel_context_get(child);
> >   	intel_gt_pm_get(ce->engine->gt);
> >   	if (!test_bit(CONTEXT_ALLOC_BIT, &ce->flags)) {
> > @@ -2418,6 +2542,13 @@ eb_select_engine(struct i915_execbuffer *eb)
> >   		if (err)
> >   			goto err;
> >   	}
> > +	for_each_child(ce, child) {
> > +		if (!test_bit(CONTEXT_ALLOC_BIT, &child->flags)) {
> > +			err = intel_context_alloc_state(child);
> > +			if (err)
> > +				goto err;
> > +		}
> > +	}
> >   	/*
> >   	 * ABI: Before userspace accesses the GPU (e.g. execbuffer), report
> > @@ -2428,7 +2559,7 @@ eb_select_engine(struct i915_execbuffer *eb)
> >   		goto err;
> >   	eb->context = ce;
> > -	eb->engine = ce->engine;
> > +	eb->gt = ce->engine->gt;
> >   	/*
> >   	 * Make sure engine pool stays alive even if we call intel_context_put
> > @@ -2439,6 +2570,8 @@ eb_select_engine(struct i915_execbuffer *eb)
> >   err:
> >   	intel_gt_pm_put(ce->engine->gt);
> > +	for_each_child(ce, child)
> > +		intel_context_put(child);
> >   	intel_context_put(ce);
> >   	return err;
> >   }
> > @@ -2446,7 +2579,11 @@ eb_select_engine(struct i915_execbuffer *eb)
> >   static void
> >   eb_put_engine(struct i915_execbuffer *eb)
> >   {
> > -	intel_gt_pm_put(eb->engine->gt);
> > +	struct intel_context *child;
> > +
> > +	intel_gt_pm_put(eb->gt);
> > +	for_each_child(eb->context, child)
> > +		intel_context_put(child);
> >   	intel_context_put(eb->context);
> >   }
> > @@ -2669,7 +2806,8 @@ static void put_fence_array(struct eb_fence *fences, int num_fences)
> >   }
> >   static int
> > -await_fence_array(struct i915_execbuffer *eb)
> > +await_fence_array(struct i915_execbuffer *eb,
> > +		  struct i915_request *rq)
> >   {
> >   	unsigned int n;
> >   	int err;
> > @@ -2683,8 +2821,7 @@ await_fence_array(struct i915_execbuffer *eb)
> >   		if (!eb->fences[n].dma_fence)
> >   			continue;
> > -		err = i915_request_await_dma_fence(eb->request,
> > -						   eb->fences[n].dma_fence);
> > +		err = i915_request_await_dma_fence(rq, eb->fences[n].dma_fence);
> >   		if (err < 0)
> >   			return err;
> >   	}
> > @@ -2692,9 +2829,9 @@ await_fence_array(struct i915_execbuffer *eb)
> >   	return 0;
> >   }
> > -static void signal_fence_array(const struct i915_execbuffer *eb)
> > +static void signal_fence_array(const struct i915_execbuffer *eb,
> > +			       struct dma_fence * const fence)
> >   {
> > -	struct dma_fence * const fence = &eb->request->fence;
> >   	unsigned int n;
> >   	for (n = 0; n < eb->num_fences; n++) {
> > @@ -2742,9 +2879,9 @@ static void retire_requests(struct intel_timeline *tl, struct i915_request *end)
> >   			break;
> >   }
> > -static int eb_request_add(struct i915_execbuffer *eb, int err)
> > +static int eb_request_add(struct i915_execbuffer *eb, struct i915_request *rq,
> > +			  int err, bool last_parallel)
> >   {
> > -	struct i915_request *rq = eb->request;
> >   	struct intel_timeline * const tl = i915_request_timeline(rq);
> >   	struct i915_sched_attr attr = {};
> >   	struct i915_request *prev;
> > @@ -2766,6 +2903,17 @@ static int eb_request_add(struct i915_execbuffer *eb, int err)
> >   		err = -ENOENT; /* override any transient errors */
> >   	}
> > +	if (intel_context_is_parallel(eb->context)) {
> > +		if (err) {
> > +			__i915_request_skip(rq);
> > +			set_bit(I915_FENCE_FLAG_SKIP_PARALLEL,
> > +				&rq->fence.flags);
> > +		}
> > +		if (last_parallel)
> > +			set_bit(I915_FENCE_FLAG_SUBMIT_PARALLEL,
> > +				&rq->fence.flags);
> > +	}
> > +
> >   	__i915_request_queue(rq, &attr);
> >   	/* Try to clean up the client's timeline after submitting the request */
> > @@ -2777,6 +2925,25 @@ static int eb_request_add(struct i915_execbuffer *eb, int err)
> >   	return err;
> >   }
> > +static int eb_requests_add(struct i915_execbuffer *eb, int err)
> > +{
> > +	int i;
> > +
> > +	/*
> > +	 * We iterate in reverse order of creation to release timeline mutexes in
> > +	 * same order.
> > +	 */
> > +	for_each_batch_add_order(eb, i) {
> > +		struct i915_request *rq = eb->requests[i];
> > +
> > +		if (!rq)
> > +			continue;
> > +		err |= eb_request_add(eb, rq, err, i == 0);
> > +	}
> > +
> > +	return err;
> > +}
> > +
> >   static const i915_user_extension_fn execbuf_extensions[] = {
> >   	[DRM_I915_GEM_EXECBUFFER_EXT_TIMELINE_FENCES] = parse_timeline_fences,
> >   };
> > @@ -2803,6 +2970,182 @@ parse_execbuf2_extensions(struct drm_i915_gem_execbuffer2 *args,
> >   				    eb);
> >   }
> > +static void eb_requests_get(struct i915_execbuffer *eb)
> > +{
> > +	unsigned int i;
> > +
> > +	for_each_batch_create_order(eb, i) {
> > +		if (!eb->requests[i])
> > +			break;
> > +
> > +		i915_request_get(eb->requests[i]);
> > +	}
> > +}
> > +
> > +static void eb_requests_put(struct i915_execbuffer *eb)
> > +{
> > +	unsigned int i;
> > +
> > +	for_each_batch_create_order(eb, i) {
> > +		if (!eb->requests[i])
> > +			break;
> > +
> > +		i915_request_put(eb->requests[i]);
> > +	}
> > +}
> > +
> > +static struct sync_file *
> > +eb_composite_fence_create(struct i915_execbuffer *eb, int out_fence_fd)
> > +{
> > +	struct sync_file *out_fence = NULL;
> > +	struct dma_fence_array *fence_array;
> > +	struct dma_fence **fences;
> > +	unsigned int i;
> > +
> > +	GEM_BUG_ON(!intel_context_is_parent(eb->context));
> > +
> > +	fences = kmalloc_array(eb->num_batches, sizeof(*fences), GFP_KERNEL);
> > +	if (!fences)
> > +		return ERR_PTR(-ENOMEM);
> > +
> > +	for_each_batch_create_order(eb, i)
> > +		fences[i] = &eb->requests[i]->fence;
> > +
> > +	fence_array = dma_fence_array_create(eb->num_batches,
> > +					     fences,
> > +					     eb->context->parallel.fence_context,
> > +					     eb->context->parallel.seqno,
> > +					     false);
> > +	if (!fence_array) {
> > +		kfree(fences);
> > +		return ERR_PTR(-ENOMEM);
> > +	}
> > +
> > +	/* Move ownership to the dma_fence_array created above */
> > +	for_each_batch_create_order(eb, i)
> > +		dma_fence_get(fences[i]);
> > +
> > +	if (out_fence_fd != -1) {
> > +		out_fence = sync_file_create(&fence_array->base);
> > +		/* sync_file now owns fence_arry, drop creation ref */
> > +		dma_fence_put(&fence_array->base);
> > +		if (!out_fence)
> > +			return ERR_PTR(-ENOMEM);
> > +	}
> > +
> > +	eb->composite_fence = &fence_array->base;
> > +
> > +	return out_fence;
> > +}
> > +
> > +static struct sync_file *
> > +eb_fences_add(struct i915_execbuffer *eb, struct i915_request *rq,
> > +	      struct dma_fence *in_fence, int out_fence_fd)
> > +{
> > +	struct sync_file *out_fence = NULL;
> > +	int err;
> > +
> > +	if (unlikely(eb->gem_context->syncobj)) {
> > +		struct dma_fence *fence;
> > +
> > +		fence = drm_syncobj_fence_get(eb->gem_context->syncobj);
> > +		err = i915_request_await_dma_fence(rq, fence);
> > +		dma_fence_put(fence);
> > +		if (err)
> > +			return ERR_PTR(err);
> > +	}
> > +
> > +	if (in_fence) {
> > +		if (eb->args->flags & I915_EXEC_FENCE_SUBMIT)
> > +			err = i915_request_await_execution(rq, in_fence);
> > +		else
> > +			err = i915_request_await_dma_fence(rq, in_fence);
> > +		if (err < 0)
> > +			return ERR_PTR(err);
> > +	}
> > +
> > +	if (eb->fences) {
> > +		err = await_fence_array(eb, rq);
> > +		if (err)
> > +			return ERR_PTR(err);
> > +	}
> > +
> > +	if (intel_context_is_parallel(eb->context)) {
> > +		out_fence = eb_composite_fence_create(eb, out_fence_fd);
> > +		if (IS_ERR(out_fence))
> > +			return ERR_PTR(-ENOMEM);
> > +	} else if (out_fence_fd != -1) {
> > +		out_fence = sync_file_create(&rq->fence);
> > +		if (!out_fence)
> > +			return ERR_PTR(-ENOMEM);
> > +	}
> > +
> > +	return out_fence;
> > +}
> > +
> > +static struct intel_context *
> > +eb_find_context(struct i915_execbuffer *eb, unsigned int context_number)
> > +{
> > +	struct intel_context *child;
> > +
> > +	if (likely(context_number == 0))
> > +		return eb->context;
> > +
> > +	for_each_child(eb->context, child)
> > +		if (!--context_number)
> > +			return child;
> > +
> > +	GEM_BUG_ON("Context not found");
> > +
> > +	return NULL;
> > +}
> > +
> > +static struct sync_file *
> > +eb_requests_create(struct i915_execbuffer *eb, struct dma_fence *in_fence,
> > +		   int out_fence_fd)
> > +{
> > +	struct sync_file *out_fence = NULL;
> > +	unsigned int i;
> > +
> > +	for_each_batch_create_order(eb, i) {
> > +		/* Allocate a request for this batch buffer nice and early. */
> > +		eb->requests[i] = i915_request_create(eb_find_context(eb, i));
> > +		if (IS_ERR(eb->requests[i])) {
> > +			out_fence = ERR_PTR(PTR_ERR(eb->requests[i]));
> > +			eb->requests[i] = NULL;
> > +			return out_fence;
> > +		}
> > +
> > +		/*
> > +		 * Only the first request added (committed to backend) has to
> > +		 * take the in fences into account as all subsequent requests
> > +		 * will have fences inserted inbetween them.
> > +		 */
> > +		if (i + 1 == eb->num_batches) {
> > +			out_fence = eb_fences_add(eb, eb->requests[i],
> > +						  in_fence, out_fence_fd);
> > +			if (IS_ERR(out_fence))
> > +				return out_fence;
> > +		}
> > +
> > +		/*
> > +		 * Whilst this request exists, batch_obj will be on the
> > +		 * active_list, and so will hold the active reference. Only when
> > +		 * this request is retired will the batch_obj be moved onto
> > +		 * the inactive_list and lose its active reference. Hence we do
> > +		 * not need to explicitly hold another reference here.
> > +		 */
> > +		eb->requests[i]->batch = eb->batches[i]->vma;
> > +		if (eb->batch_pool) {
> > +			GEM_BUG_ON(intel_context_is_parallel(eb->context));
> > +			intel_gt_buffer_pool_mark_active(eb->batch_pool,
> > +							 eb->requests[i]);
> > +		}
> > +	}
> > +
> > +	return out_fence;
> > +}
> > +
> >   static int
> >   i915_gem_do_execbuffer(struct drm_device *dev,
> >   		       struct drm_file *file,
> > @@ -2813,7 +3156,6 @@ i915_gem_do_execbuffer(struct drm_device *dev,
> >   	struct i915_execbuffer eb;
> >   	struct dma_fence *in_fence = NULL;
> >   	struct sync_file *out_fence = NULL;
> > -	struct i915_vma *batch;
> >   	int out_fence_fd = -1;
> >   	int err;
> > @@ -2837,12 +3179,15 @@ i915_gem_do_execbuffer(struct drm_device *dev,
> >   	eb.buffer_count = args->buffer_count;
> >   	eb.batch_start_offset = args->batch_start_offset;
> > -	eb.batch_len = args->batch_len;
> >   	eb.trampoline = NULL;
> >   	eb.fences = NULL;
> >   	eb.num_fences = 0;
> > +	memset(eb.requests, 0, sizeof(struct i915_request *) *
> > +	       ARRAY_SIZE(eb.requests));
> > +	eb.composite_fence = NULL;
> > +
> >   	eb.batch_flags = 0;
> >   	if (args->flags & I915_EXEC_SECURE) {
> >   		if (GRAPHICS_VER(i915) >= 11)
> > @@ -2926,70 +3271,25 @@ i915_gem_do_execbuffer(struct drm_device *dev,
> >   	ww_acquire_done(&eb.ww.ctx);
> > -	batch = eb.batch->vma;
> > -
> > -	/* Allocate a request for this batch buffer nice and early. */
> > -	eb.request = i915_request_create(eb.context);
> > -	if (IS_ERR(eb.request)) {
> > -		err = PTR_ERR(eb.request);
> > -		goto err_vma;
> > -	}
> > -
> > -	if (unlikely(eb.gem_context->syncobj)) {
> > -		struct dma_fence *fence;
> > -
> > -		fence = drm_syncobj_fence_get(eb.gem_context->syncobj);
> > -		err = i915_request_await_dma_fence(eb.request, fence);
> > -		dma_fence_put(fence);
> > -		if (err)
> > -			goto err_ext;
> > -	}
> > -
> > -	if (in_fence) {
> > -		if (args->flags & I915_EXEC_FENCE_SUBMIT)
> > -			err = i915_request_await_execution(eb.request,
> > -							   in_fence);
> > -		else
> > -			err = i915_request_await_dma_fence(eb.request,
> > -							   in_fence);
> > -		if (err < 0)
> > -			goto err_request;
> > -	}
> > -
> > -	if (eb.fences) {
> > -		err = await_fence_array(&eb);
> > -		if (err)
> > +	out_fence = eb_requests_create(&eb, in_fence, out_fence_fd);
> > +	if (IS_ERR(out_fence)) {
> > +		err = PTR_ERR(out_fence);
> > +		if (eb.requests[0])
> >   			goto err_request;
> > +		else
> > +			goto err_vma;
> >   	}
> > -	if (out_fence_fd != -1) {
> > -		out_fence = sync_file_create(&eb.request->fence);
> > -		if (!out_fence) {
> > -			err = -ENOMEM;
> > -			goto err_request;
> > -		}
> > -	}
> > -
> > -	/*
> > -	 * Whilst this request exists, batch_obj will be on the
> > -	 * active_list, and so will hold the active reference. Only when this
> > -	 * request is retired will the the batch_obj be moved onto the
> > -	 * inactive_list and lose its active reference. Hence we do not need
> > -	 * to explicitly hold another reference here.
> > -	 */
> > -	eb.request->batch = batch;
> > -	if (eb.batch_pool)
> > -		intel_gt_buffer_pool_mark_active(eb.batch_pool, eb.request);
> > -
> > -	trace_i915_request_queue(eb.request, eb.batch_flags);
> > -	err = eb_submit(&eb, batch);
> > +	err = eb_submit(&eb);
> >   err_request:
> > -	i915_request_get(eb.request);
> > -	err = eb_request_add(&eb, err);
> > +	eb_requests_get(&eb);
> > +	err = eb_requests_add(&eb, err);
> >   	if (eb.fences)
> > -		signal_fence_array(&eb);
> > +		signal_fence_array(&eb, eb.composite_fence ?
> > +				   eb.composite_fence :
> > +				   &eb.requests[0]->fence);
> >   	if (out_fence) {
> >   		if (err == 0) {
> > @@ -3004,10 +3304,15 @@ i915_gem_do_execbuffer(struct drm_device *dev,
> >   	if (unlikely(eb.gem_context->syncobj)) {
> >   		drm_syncobj_replace_fence(eb.gem_context->syncobj,
> > -					  &eb.request->fence);
> > +					  eb.composite_fence ?
> > +					  eb.composite_fence :
> > +					  &eb.requests[0]->fence);
> >   	}
> > -	i915_request_put(eb.request);
> > +	if (!out_fence && eb.composite_fence)
> > +		dma_fence_put(eb.composite_fence);
> > +
> > +	eb_requests_put(&eb);
> >   err_vma:
> >   	eb_release_vmas(&eb, true);
> > diff --git a/drivers/gpu/drm/i915/gt/intel_context.h b/drivers/gpu/drm/i915/gt/intel_context.h
> > index 1bc705f98e2a..1781419fa105 100644
> > --- a/drivers/gpu/drm/i915/gt/intel_context.h
> > +++ b/drivers/gpu/drm/i915/gt/intel_context.h
> > @@ -239,7 +239,13 @@ intel_context_timeline_lock(struct intel_context *ce)
> >   	struct intel_timeline *tl = ce->timeline;
> >   	int err;
> > -	err = mutex_lock_interruptible(&tl->mutex);
> > +	if (intel_context_is_parent(ce))
> > +		err = mutex_lock_interruptible_nested(&tl->mutex, 0);
> > +	else if (intel_context_is_child(ce))
> > +		err = mutex_lock_interruptible_nested(&tl->mutex,
> > +						      ce->parallel.child_index + 1);
> > +	else
> > +		err = mutex_lock_interruptible(&tl->mutex);
> >   	if (err)
> >   		return ERR_PTR(err);
> > diff --git a/drivers/gpu/drm/i915/gt/intel_context_types.h b/drivers/gpu/drm/i915/gt/intel_context_types.h
> > index 95a5b94b4ece..9e0177dc5484 100644
> > --- a/drivers/gpu/drm/i915/gt/intel_context_types.h
> > +++ b/drivers/gpu/drm/i915/gt/intel_context_types.h
> > @@ -248,6 +248,16 @@ struct intel_context {
> >   		 * context
> >   		 */
> >   		struct i915_request *last_rq;
> > +		/**
> > +		 * @fence_context: fence context composite fence when doing
> > +		 * parallel submission
> > +		 */
> > +		u64 fence_context;
> > +		/**
> > +		 * @seqno: seqno for composite fence when doing parallel
> > +		 * submission
> > +		 */
> > +		u32 seqno;
> >   		/** @number_children: number of children if parent */
> >   		u8 number_children;
> >   		/** @child_index: index into child_list if child */
> > diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
> > index ae08a196ba0a..bfafe996e2d2 100644
> > --- a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
> > +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
> > @@ -3099,6 +3099,8 @@ guc_create_parallel(struct intel_engine_cs **engines,
> >   		}
> >   	}
> > +	parent->parallel.fence_context = dma_fence_context_alloc(1);
> > +
> >   	parent->engine->emit_bb_start =
> >   		emit_bb_start_parent_no_preempt_mid_batch;
> >   	parent->engine->emit_fini_breadcrumb =
> > diff --git a/drivers/gpu/drm/i915/i915_request.h b/drivers/gpu/drm/i915/i915_request.h
> > index 8950785e55d6..24db8459376b 100644
> > --- a/drivers/gpu/drm/i915/i915_request.h
> > +++ b/drivers/gpu/drm/i915/i915_request.h
> > @@ -147,6 +147,15 @@ enum {
> >   	 * tail.
> >   	 */
> >   	I915_FENCE_FLAG_SUBMIT_PARALLEL,
> > +
> > +	/*
> > +	 * I915_FENCE_FLAG_SKIP_PARALLEL - request with a context in a
> > +	 * parent-child relationship (parallel submission, multi-lrc) that
> > +	 * hit an error while generating requests in the execbuf IOCTL.
> > +	 * Indicates this request should be skipped as another request in
> > +	 * submission / relationship encoutered an error.
> > +	 */
> > +	I915_FENCE_FLAG_SKIP_PARALLEL,
> >   };
> >   /**
> > diff --git a/drivers/gpu/drm/i915/i915_vma.c b/drivers/gpu/drm/i915/i915_vma.c
> > index 4b7fc4647e46..90546fa58fc1 100644
> > --- a/drivers/gpu/drm/i915/i915_vma.c
> > +++ b/drivers/gpu/drm/i915/i915_vma.c
> > @@ -1234,9 +1234,10 @@ int __i915_vma_move_to_active(struct i915_vma *vma, struct i915_request *rq)
> >   	return i915_active_add_request(&vma->active, rq);
> >   }
> > -int i915_vma_move_to_active(struct i915_vma *vma,
> > -			    struct i915_request *rq,
> > -			    unsigned int flags)
> > +int _i915_vma_move_to_active(struct i915_vma *vma,
> > +			     struct i915_request *rq,
> > +			     struct dma_fence *fence,
> > +			     unsigned int flags)
> >   {
> >   	struct drm_i915_gem_object *obj = vma->obj;
> >   	int err;
> > @@ -1257,9 +1258,11 @@ int i915_vma_move_to_active(struct i915_vma *vma,
> >   			intel_frontbuffer_put(front);
> >   		}
> > -		dma_resv_add_excl_fence(vma->resv, &rq->fence);
> > -		obj->write_domain = I915_GEM_DOMAIN_RENDER;
> > -		obj->read_domains = 0;
> > +		if (fence) {
> > +			dma_resv_add_excl_fence(vma->resv, fence);
> > +			obj->write_domain = I915_GEM_DOMAIN_RENDER;
> > +			obj->read_domains = 0;
> > +		}
> >   	} else {
> >   		if (!(flags & __EXEC_OBJECT_NO_RESERVE)) {
> >   			err = dma_resv_reserve_shared(vma->resv, 1);
> > @@ -1267,8 +1270,10 @@ int i915_vma_move_to_active(struct i915_vma *vma,
> >   				return err;
> >   		}
> > -		dma_resv_add_shared_fence(vma->resv, &rq->fence);
> > -		obj->write_domain = 0;
> > +		if (fence) {
> > +			dma_resv_add_shared_fence(vma->resv, fence);
> > +			obj->write_domain = 0;
> > +		}
> >   	}
> >   	if (flags & EXEC_OBJECT_NEEDS_FENCE && vma->fence)
> > diff --git a/drivers/gpu/drm/i915/i915_vma.h b/drivers/gpu/drm/i915/i915_vma.h
> > index ed69f66c7ab0..648dbe744c96 100644
> > --- a/drivers/gpu/drm/i915/i915_vma.h
> > +++ b/drivers/gpu/drm/i915/i915_vma.h
> > @@ -57,9 +57,16 @@ static inline bool i915_vma_is_active(const struct i915_vma *vma)
> >   int __must_check __i915_vma_move_to_active(struct i915_vma *vma,
> >   					   struct i915_request *rq);
> > -int __must_check i915_vma_move_to_active(struct i915_vma *vma,
> > -					 struct i915_request *rq,
> > -					 unsigned int flags);
> > +int __must_check _i915_vma_move_to_active(struct i915_vma *vma,
> > +					  struct i915_request *rq,
> > +					  struct dma_fence *fence,
> > +					  unsigned int flags);
> > +static inline int __must_check
> > +i915_vma_move_to_active(struct i915_vma *vma, struct i915_request *rq,
> > +			unsigned int flags)
> > +{
> > +	return _i915_vma_move_to_active(vma, rq, &rq->fence, flags);
> > +}
> >   #define __i915_vma_flags(v) ((unsigned long *)&(v)->flags.counter)
>

Patch

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c
index c75afc8784e3..6509c9d8c298 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c
@@ -246,17 +246,25 @@  struct i915_execbuffer {
 	struct drm_i915_gem_exec_object2 *exec; /** ioctl execobj[] */
 	struct eb_vma *vma;
 
-	struct intel_engine_cs *engine; /** engine to queue the request to */
+	struct intel_gt *gt; /* gt for the execbuf */
 	struct intel_context *context; /* logical state for the request */
 	struct i915_gem_context *gem_context; /** caller's context */
 
-	struct i915_request *request; /** our request to build */
-	struct eb_vma *batch; /** identity of the batch obj/vma */
+	/** our requests to build */
+	struct i915_request *requests[MAX_ENGINE_INSTANCE + 1];
+	/** identity of the batch obj/vma */
+	struct eb_vma *batches[MAX_ENGINE_INSTANCE + 1];
 	struct i915_vma *trampoline; /** trampoline used for chaining */
 
+	/** used for excl fence in dma_resv objects when > 1 BB submitted */
+	struct dma_fence *composite_fence;
+
 	/** actual size of execobj[] as we may extend it for the cmdparser */
 	unsigned int buffer_count;
 
+	/* number of batches in execbuf IOCTL */
+	unsigned int num_batches;
+
 	/** list of vma not yet bound during reservation phase */
 	struct list_head unbound;
 
@@ -283,7 +291,8 @@  struct i915_execbuffer {
 
 	u64 invalid_flags; /** Set of execobj.flags that are invalid */
 
-	u64 batch_len; /** Length of batch within object */
+	/** Length of batch within object */
+	u64 batch_len[MAX_ENGINE_INSTANCE + 1];
 	u32 batch_start_offset; /** Location within object of batch */
 	u32 batch_flags; /** Flags composed for emit_bb_start() */
 	struct intel_gt_buffer_pool_node *batch_pool; /** pool node for batch buffer */
@@ -301,14 +310,13 @@  struct i915_execbuffer {
 };
 
 static int eb_parse(struct i915_execbuffer *eb);
-static struct i915_request *eb_pin_engine(struct i915_execbuffer *eb,
-					  bool throttle);
+static int eb_pin_engine(struct i915_execbuffer *eb, bool throttle);
 static void eb_unpin_engine(struct i915_execbuffer *eb);
 
 static inline bool eb_use_cmdparser(const struct i915_execbuffer *eb)
 {
-	return intel_engine_requires_cmd_parser(eb->engine) ||
-		(intel_engine_using_cmd_parser(eb->engine) &&
+	return intel_engine_requires_cmd_parser(eb->context->engine) ||
+		(intel_engine_using_cmd_parser(eb->context->engine) &&
 		 eb->args->batch_len);
 }
 
@@ -546,11 +554,21 @@  eb_validate_vma(struct i915_execbuffer *eb,
 	return 0;
 }
 
-static void
+static inline bool
+is_batch_buffer(struct i915_execbuffer *eb, unsigned int buffer_idx)
+{
+	return eb->args->flags & I915_EXEC_BATCH_FIRST ?
+		buffer_idx < eb->num_batches :
+		buffer_idx >= eb->args->buffer_count - eb->num_batches;
+}
+
+static int
 eb_add_vma(struct i915_execbuffer *eb,
-	   unsigned int i, unsigned batch_idx,
+	   unsigned int *current_batch,
+	   unsigned int i,
 	   struct i915_vma *vma)
 {
+	struct drm_i915_private *i915 = eb->i915;
 	struct drm_i915_gem_exec_object2 *entry = &eb->exec[i];
 	struct eb_vma *ev = &eb->vma[i];
 
@@ -577,15 +595,43 @@  eb_add_vma(struct i915_execbuffer *eb,
 	 * Note that actual hangs have only been observed on gen7, but for
 	 * paranoia do it everywhere.
 	 */
-	if (i == batch_idx) {
+	if (is_batch_buffer(eb, i)) {
 		if (entry->relocation_count &&
 		    !(ev->flags & EXEC_OBJECT_PINNED))
 			ev->flags |= __EXEC_OBJECT_NEEDS_BIAS;
 		if (eb->reloc_cache.has_fence)
 			ev->flags |= EXEC_OBJECT_NEEDS_FENCE;
 
-		eb->batch = ev;
+		eb->batches[*current_batch] = ev;
+
+		if (unlikely(ev->flags & EXEC_OBJECT_WRITE)) {
+			drm_dbg(&i915->drm,
+				"Attempting to use self-modifying batch buffer\n");
+			return -EINVAL;
+		}
+
+		if (range_overflows_t(u64,
+				      eb->batch_start_offset,
+				      eb->args->batch_len,
+				      ev->vma->size)) {
+			drm_dbg(&i915->drm, "Attempting to use out-of-bounds batch\n");
+			return -EINVAL;
+		}
+
+		if (eb->args->batch_len == 0)
+			eb->batch_len[*current_batch] = ev->vma->size -
+				eb->batch_start_offset;
+		else
+			eb->batch_len[*current_batch] = eb->args->batch_len;
+		if (unlikely(eb->batch_len[*current_batch] == 0)) { /* impossible! */
+			drm_dbg(&i915->drm, "Invalid batch length\n");
+			return -EINVAL;
+		}
+
+		++*current_batch;
 	}
+
+	return 0;
 }
 
 static inline int use_cpu_reloc(const struct reloc_cache *cache,
@@ -729,14 +775,6 @@  static int eb_reserve(struct i915_execbuffer *eb)
 	} while (1);
 }
 
-static unsigned int eb_batch_index(const struct i915_execbuffer *eb)
-{
-	if (eb->args->flags & I915_EXEC_BATCH_FIRST)
-		return 0;
-	else
-		return eb->buffer_count - 1;
-}
-
 static int eb_select_context(struct i915_execbuffer *eb)
 {
 	struct i915_gem_context *ctx;
@@ -857,9 +895,7 @@  static struct i915_vma *eb_lookup_vma(struct i915_execbuffer *eb, u32 handle)
 
 static int eb_lookup_vmas(struct i915_execbuffer *eb)
 {
-	struct drm_i915_private *i915 = eb->i915;
-	unsigned int batch = eb_batch_index(eb);
-	unsigned int i;
+	unsigned int i, current_batch = 0;
 	int err = 0;
 
 	INIT_LIST_HEAD(&eb->relocs);
@@ -879,7 +915,9 @@  static int eb_lookup_vmas(struct i915_execbuffer *eb)
 			goto err;
 		}
 
-		eb_add_vma(eb, i, batch, vma);
+		err = eb_add_vma(eb, &current_batch, i, vma);
+		if (err)
+			return err;
 
 		if (i915_gem_object_is_userptr(vma->obj)) {
 			err = i915_gem_object_userptr_submit_init(vma->obj);
@@ -902,26 +940,6 @@  static int eb_lookup_vmas(struct i915_execbuffer *eb)
 		}
 	}
 
-	if (unlikely(eb->batch->flags & EXEC_OBJECT_WRITE)) {
-		drm_dbg(&i915->drm,
-			"Attempting to use self-modifying batch buffer\n");
-		return -EINVAL;
-	}
-
-	if (range_overflows_t(u64,
-			      eb->batch_start_offset, eb->batch_len,
-			      eb->batch->vma->size)) {
-		drm_dbg(&i915->drm, "Attempting to use out-of-bounds batch\n");
-		return -EINVAL;
-	}
-
-	if (eb->batch_len == 0)
-		eb->batch_len = eb->batch->vma->size - eb->batch_start_offset;
-	if (unlikely(eb->batch_len == 0)) { /* impossible! */
-		drm_dbg(&i915->drm, "Invalid batch length\n");
-		return -EINVAL;
-	}
-
 	return 0;
 
 err:
@@ -1654,8 +1672,7 @@  static int eb_reinit_userptr(struct i915_execbuffer *eb)
 	return 0;
 }
 
-static noinline int eb_relocate_parse_slow(struct i915_execbuffer *eb,
-					   struct i915_request *rq)
+static noinline int eb_relocate_parse_slow(struct i915_execbuffer *eb)
 {
 	bool have_copy = false;
 	struct eb_vma *ev;
@@ -1671,21 +1688,6 @@  static noinline int eb_relocate_parse_slow(struct i915_execbuffer *eb,
 	eb_release_vmas(eb, false);
 	i915_gem_ww_ctx_fini(&eb->ww);
 
-	if (rq) {
-		/* nonblocking is always false */
-		if (i915_request_wait(rq, I915_WAIT_INTERRUPTIBLE,
-				      MAX_SCHEDULE_TIMEOUT) < 0) {
-			i915_request_put(rq);
-			rq = NULL;
-
-			err = -EINTR;
-			goto err_relock;
-		}
-
-		i915_request_put(rq);
-		rq = NULL;
-	}
-
 	/*
 	 * We take 3 passes through the slowpatch.
 	 *
@@ -1712,28 +1714,21 @@  static noinline int eb_relocate_parse_slow(struct i915_execbuffer *eb,
 	if (!err)
 		err = eb_reinit_userptr(eb);
 
-err_relock:
 	i915_gem_ww_ctx_init(&eb->ww, true);
 	if (err)
 		goto out;
 
 	/* reacquire the objects */
 repeat_validate:
-	rq = eb_pin_engine(eb, false);
-	if (IS_ERR(rq)) {
-		err = PTR_ERR(rq);
-		rq = NULL;
+	err = eb_pin_engine(eb, false);
+	if (err)
 		goto err;
-	}
-
-	/* We didn't throttle, should be NULL */
-	GEM_WARN_ON(rq);
 
 	err = eb_validate_vmas(eb);
 	if (err)
 		goto err;
 
-	GEM_BUG_ON(!eb->batch);
+	GEM_BUG_ON(!eb->batches[0]);
 
 	list_for_each_entry(ev, &eb->relocs, reloc_link) {
 		if (!have_copy) {
@@ -1797,46 +1792,23 @@  static noinline int eb_relocate_parse_slow(struct i915_execbuffer *eb,
 		}
 	}
 
-	if (rq)
-		i915_request_put(rq);
-
 	return err;
 }
 
 static int eb_relocate_parse(struct i915_execbuffer *eb)
 {
 	int err;
-	struct i915_request *rq = NULL;
 	bool throttle = true;
 
 retry:
-	rq = eb_pin_engine(eb, throttle);
-	if (IS_ERR(rq)) {
-		err = PTR_ERR(rq);
-		rq = NULL;
+	err = eb_pin_engine(eb, throttle);
+	if (err) {
 		if (err != -EDEADLK)
 			return err;
 
 		goto err;
 	}
 
-	if (rq) {
-		bool nonblock = eb->file->filp->f_flags & O_NONBLOCK;
-
-		/* Need to drop all locks now for throttling, take slowpath */
-		err = i915_request_wait(rq, I915_WAIT_INTERRUPTIBLE, 0);
-		if (err == -ETIME) {
-			if (nonblock) {
-				err = -EWOULDBLOCK;
-				i915_request_put(rq);
-				goto err;
-			}
-			goto slow;
-		}
-		i915_request_put(rq);
-		rq = NULL;
-	}
-
 	/* only throttle once, even if we didn't need to throttle */
 	throttle = false;
 
@@ -1876,7 +1848,7 @@  static int eb_relocate_parse(struct i915_execbuffer *eb)
 	return err;
 
 slow:
-	err = eb_relocate_parse_slow(eb, rq);
+	err = eb_relocate_parse_slow(eb);
 	if (err)
 		/*
 		 * If the user expects the execobject.offset and
@@ -1890,11 +1862,40 @@  static int eb_relocate_parse(struct i915_execbuffer *eb)
 	return err;
 }
 
+/*
+ * Using two helper loops for the order of which requests / batches are created
+ * and added the to backend. Requests are created in order from the parent to
+ * the last child. Requests are add in the reverse order, from the last child to
+ * parent. This is down from locking reasons as the timeline lock is acquired
+ * during request creation and released when the request is added to the
+ * backend. To make lockdep happy (see intel_context_timeline_lock) this must be
+ * the ordering.
+ */
+#define for_each_batch_create_order(_eb, _i) \
+	for ((_i) = 0; (_i) < (_eb)->num_batches; ++(_i))
+#define for_each_batch_add_order(_eb, _i) \
+	BUILD_BUG_ON(!typecheck(int, _i)); \
+	for ((_i) = (_eb)->num_batches - 1; (_i) >= 0; --(_i))
+
+static struct i915_request *
+eb_find_first_request_added(struct i915_execbuffer *eb)
+{
+	int i;
+
+	for_each_batch_add_order(eb, i)
+		if (eb->requests[i])
+			return eb->requests[i];
+
+	GEM_BUG_ON("Request not found");
+
+	return NULL;
+}
+
 static int eb_move_to_gpu(struct i915_execbuffer *eb)
 {
 	const unsigned int count = eb->buffer_count;
 	unsigned int i = count;
-	int err = 0;
+	int err = 0, j;
 
 	while (i--) {
 		struct eb_vma *ev = &eb->vma[i];
@@ -1907,11 +1908,17 @@  static int eb_move_to_gpu(struct i915_execbuffer *eb)
 		if (flags & EXEC_OBJECT_CAPTURE) {
 			struct i915_capture_list *capture;
 
-			capture = kmalloc(sizeof(*capture), GFP_KERNEL);
-			if (capture) {
-				capture->next = eb->request->capture_list;
-				capture->vma = vma;
-				eb->request->capture_list = capture;
+			for_each_batch_create_order(eb, j) {
+				if (!eb->requests[j])
+					break;
+
+				capture = kmalloc(sizeof(*capture), GFP_KERNEL);
+				if (capture) {
+					capture->next =
+						eb->requests[j]->capture_list;
+					capture->vma = vma;
+					eb->requests[j]->capture_list = capture;
+				}
 			}
 		}
 
@@ -1932,14 +1939,26 @@  static int eb_move_to_gpu(struct i915_execbuffer *eb)
 				flags &= ~EXEC_OBJECT_ASYNC;
 		}
 
+		/* We only need to await on the first request */
 		if (err == 0 && !(flags & EXEC_OBJECT_ASYNC)) {
 			err = i915_request_await_object
-				(eb->request, obj, flags & EXEC_OBJECT_WRITE);
+				(eb_find_first_request_added(eb), obj,
+				 flags & EXEC_OBJECT_WRITE);
 		}
 
-		if (err == 0)
-			err = i915_vma_move_to_active(vma, eb->request,
-						      flags | __EXEC_OBJECT_NO_RESERVE);
+		for_each_batch_add_order(eb, j) {
+			if (err)
+				break;
+			if (!eb->requests[j])
+				continue;
+
+			err = _i915_vma_move_to_active(vma, eb->requests[j],
+						       j ? NULL :
+						       eb->composite_fence ?
+						       eb->composite_fence :
+						       &eb->requests[j]->fence,
+						       flags | __EXEC_OBJECT_NO_RESERVE);
+		}
 	}
 
 #ifdef CONFIG_MMU_NOTIFIER
@@ -1970,11 +1989,16 @@  static int eb_move_to_gpu(struct i915_execbuffer *eb)
 		goto err_skip;
 
 	/* Unconditionally flush any chipset caches (for streaming writes). */
-	intel_gt_chipset_flush(eb->engine->gt);
+	intel_gt_chipset_flush(eb->gt);
 	return 0;
 
 err_skip:
-	i915_request_set_error_once(eb->request, err);
+	for_each_batch_create_order(eb, j) {
+		if (!eb->requests[j])
+			break;
+
+		i915_request_set_error_once(eb->requests[j], err);
+	}
 	return err;
 }
 
@@ -2069,14 +2093,17 @@  static int eb_parse(struct i915_execbuffer *eb)
 	int err;
 
 	if (!eb_use_cmdparser(eb)) {
-		batch = eb_dispatch_secure(eb, eb->batch->vma);
+		batch = eb_dispatch_secure(eb, eb->batches[0]->vma);
 		if (IS_ERR(batch))
 			return PTR_ERR(batch);
 
 		goto secure_batch;
 	}
 
-	len = eb->batch_len;
+	if (intel_context_is_parallel(eb->context))
+		return -EINVAL;
+
+	len = eb->batch_len[0];
 	if (!CMDPARSER_USES_GGTT(eb->i915)) {
 		/*
 		 * ppGTT backed shadow buffers must be mapped RO, to prevent
@@ -2090,11 +2117,11 @@  static int eb_parse(struct i915_execbuffer *eb)
 	} else {
 		len += I915_CMD_PARSER_TRAMPOLINE_SIZE;
 	}
-	if (unlikely(len < eb->batch_len)) /* last paranoid check of overflow */
+	if (unlikely(len < eb->batch_len[0])) /* last paranoid check of overflow */
 		return -EINVAL;
 
 	if (!pool) {
-		pool = intel_gt_get_buffer_pool(eb->engine->gt, len,
+		pool = intel_gt_get_buffer_pool(eb->gt, len,
 						I915_MAP_WB);
 		if (IS_ERR(pool))
 			return PTR_ERR(pool);
@@ -2119,7 +2146,7 @@  static int eb_parse(struct i915_execbuffer *eb)
 		trampoline = shadow;
 
 		shadow = shadow_batch_pin(eb, pool->obj,
-					  &eb->engine->gt->ggtt->vm,
+					  &eb->gt->ggtt->vm,
 					  PIN_GLOBAL);
 		if (IS_ERR(shadow)) {
 			err = PTR_ERR(shadow);
@@ -2141,26 +2168,29 @@  static int eb_parse(struct i915_execbuffer *eb)
 	if (err)
 		goto err_trampoline;
 
-	err = intel_engine_cmd_parser(eb->engine,
-				      eb->batch->vma,
+	err = intel_engine_cmd_parser(eb->context->engine,
+				      eb->batches[0]->vma,
 				      eb->batch_start_offset,
-				      eb->batch_len,
+				      eb->batch_len[0],
 				      shadow, trampoline);
 	if (err)
 		goto err_unpin_batch;
 
-	eb->batch = &eb->vma[eb->buffer_count++];
-	eb->batch->vma = i915_vma_get(shadow);
-	eb->batch->flags = __EXEC_OBJECT_HAS_PIN;
+	eb->batches[0] = &eb->vma[eb->buffer_count++];
+	eb->batches[0]->vma = i915_vma_get(shadow);
+	eb->batches[0]->flags = __EXEC_OBJECT_HAS_PIN;
 
 	eb->trampoline = trampoline;
 	eb->batch_start_offset = 0;
 
 secure_batch:
 	if (batch) {
-		eb->batch = &eb->vma[eb->buffer_count++];
-		eb->batch->flags = __EXEC_OBJECT_HAS_PIN;
-		eb->batch->vma = i915_vma_get(batch);
+		if (intel_context_is_parallel(eb->context))
+			return -EINVAL;
+
+		eb->batches[0] = &eb->vma[eb->buffer_count++];
+		eb->batches[0]->flags = __EXEC_OBJECT_HAS_PIN;
+		eb->batches[0]->vma = i915_vma_get(batch);
 	}
 	return 0;
 
@@ -2176,19 +2206,18 @@  static int eb_parse(struct i915_execbuffer *eb)
 	return err;
 }
 
-static int eb_submit(struct i915_execbuffer *eb, struct i915_vma *batch)
+static int eb_request_submit(struct i915_execbuffer *eb,
+			     struct i915_request *rq,
+			     struct i915_vma *batch,
+			     u64 batch_len)
 {
 	int err;
 
-	if (intel_context_nopreempt(eb->context))
-		__set_bit(I915_FENCE_FLAG_NOPREEMPT, &eb->request->fence.flags);
-
-	err = eb_move_to_gpu(eb);
-	if (err)
-		return err;
+	if (intel_context_nopreempt(rq->context))
+		__set_bit(I915_FENCE_FLAG_NOPREEMPT, &rq->fence.flags);
 
 	if (eb->args->flags & I915_EXEC_GEN7_SOL_RESET) {
-		err = i915_reset_gen7_sol_offsets(eb->request);
+		err = i915_reset_gen7_sol_offsets(rq);
 		if (err)
 			return err;
 	}
@@ -2199,26 +2228,26 @@  static int eb_submit(struct i915_execbuffer *eb, struct i915_vma *batch)
 	 * allows us to determine if the batch is still waiting on the GPU
 	 * or actually running by checking the breadcrumb.
 	 */
-	if (eb->engine->emit_init_breadcrumb) {
-		err = eb->engine->emit_init_breadcrumb(eb->request);
+	if (rq->context->engine->emit_init_breadcrumb) {
+		err = rq->context->engine->emit_init_breadcrumb(rq);
 		if (err)
 			return err;
 	}
 
-	err = eb->engine->emit_bb_start(eb->request,
-					batch->node.start +
-					eb->batch_start_offset,
-					eb->batch_len,
-					eb->batch_flags);
+	err = rq->context->engine->emit_bb_start(rq,
+						 batch->node.start +
+						 eb->batch_start_offset,
+						 batch_len,
+						 eb->batch_flags);
 	if (err)
 		return err;
 
 	if (eb->trampoline) {
+		GEM_BUG_ON(intel_context_is_parallel(rq->context));
 		GEM_BUG_ON(eb->batch_start_offset);
-		err = eb->engine->emit_bb_start(eb->request,
-						eb->trampoline->node.start +
-						eb->batch_len,
-						0, 0);
+		err = rq->context->engine->emit_bb_start(rq,
+							 eb->trampoline->node.start +
+							 batch_len, 0, 0);
 		if (err)
 			return err;
 	}
@@ -2226,6 +2255,27 @@  static int eb_submit(struct i915_execbuffer *eb, struct i915_vma *batch)
 	return 0;
 }
 
+static int eb_submit(struct i915_execbuffer *eb)
+{
+	unsigned int i;
+	int err;
+
+	err = eb_move_to_gpu(eb);
+
+	for_each_batch_create_order(eb, i) {
+		if (!eb->requests[i])
+			break;
+
+		trace_i915_request_queue(eb->requests[i], eb->batch_flags);
+		if (!err)
+			err = eb_request_submit(eb, eb->requests[i],
+						eb->batches[i]->vma,
+						eb->batch_len[i]);
+	}
+
+	return err;
+}
+
 static int num_vcs_engines(const struct drm_i915_private *i915)
 {
 	return hweight_long(VDBOX_MASK(&i915->gt));
@@ -2291,26 +2341,11 @@  static struct i915_request *eb_throttle(struct i915_execbuffer *eb, struct intel
 	return i915_request_get(rq);
 }
 
-static struct i915_request *eb_pin_engine(struct i915_execbuffer *eb, bool throttle)
+static int eb_pin_timeline(struct i915_execbuffer *eb, struct intel_context *ce,
+			   bool throttle)
 {
-	struct intel_context *ce = eb->context;
 	struct intel_timeline *tl;
 	struct i915_request *rq = NULL;
-	int err;
-
-	GEM_BUG_ON(eb->args->flags & __EXEC_ENGINE_PINNED);
-
-	if (unlikely(intel_context_is_banned(ce)))
-		return ERR_PTR(-EIO);
-
-	/*
-	 * Pinning the contexts may generate requests in order to acquire
-	 * GGTT space, so do this first before we reserve a seqno for
-	 * ourselves.
-	 */
-	err = intel_context_pin_ww(ce, &eb->ww);
-	if (err)
-		return ERR_PTR(err);
 
 	/*
 	 * Take a local wakeref for preparing to dispatch the execbuf as
@@ -2321,33 +2356,108 @@  static struct i915_request *eb_pin_engine(struct i915_execbuffer *eb, bool throt
 	 * taken on the engine, and the parent device.
 	 */
 	tl = intel_context_timeline_lock(ce);
-	if (IS_ERR(tl)) {
-		intel_context_unpin(ce);
-		return ERR_CAST(tl);
-	}
+	if (IS_ERR(tl))
+		return PTR_ERR(tl);
 
 	intel_context_enter(ce);
 	if (throttle)
 		rq = eb_throttle(eb, ce);
 	intel_context_timeline_unlock(tl);
 
+	if (rq) {
+		bool nonblock = eb->file->filp->f_flags & O_NONBLOCK;
+		long timeout = nonblock ? 0 : MAX_SCHEDULE_TIMEOUT;
+
+		if (i915_request_wait(rq, I915_WAIT_INTERRUPTIBLE,
+				      timeout) < 0) {
+			i915_request_put(rq);
+
+			tl = intel_context_timeline_lock(ce);
+			intel_context_exit(ce);
+			intel_context_timeline_unlock(tl);
+
+			if (nonblock)
+				return -EWOULDBLOCK;
+			else
+				return -EINTR;
+		}
+		i915_request_put(rq);
+	}
+
+	return 0;
+}
+
+static int eb_pin_engine(struct i915_execbuffer *eb, bool throttle)
+{
+	struct intel_context *ce = eb->context, *child;
+	int err;
+	int i = 0, j = 0;
+
+	GEM_BUG_ON(eb->args->flags & __EXEC_ENGINE_PINNED);
+
+	if (unlikely(intel_context_is_banned(ce)))
+		return -EIO;
+
+	/*
+	 * Pinning the contexts may generate requests in order to acquire
+	 * GGTT space, so do this first before we reserve a seqno for
+	 * ourselves.
+	 */
+	err = intel_context_pin_ww(ce, &eb->ww);
+	if (err)
+		return err;
+	for_each_child(ce, child) {
+		err = intel_context_pin_ww(child, &eb->ww);
+		GEM_BUG_ON(err);	/* perma-pinned should incr a counter */
+	}
+
+	for_each_child(ce, child) {
+		err = eb_pin_timeline(eb, child, throttle);
+		if (err)
+			goto unwind;
+		++i;
+	}
+	err = eb_pin_timeline(eb, ce, throttle);
+	if (err)
+		goto unwind;
+
 	eb->args->flags |= __EXEC_ENGINE_PINNED;
-	return rq;
+	return 0;
+
+unwind:
+	for_each_child(ce, child) {
+		if (j++ < i) {
+			mutex_lock(&child->timeline->mutex);
+			intel_context_exit(child);
+			mutex_unlock(&child->timeline->mutex);
+		}
+	}
+	for_each_child(ce, child)
+		intel_context_unpin(child);
+	intel_context_unpin(ce);
+	return err;
 }
 
 static void eb_unpin_engine(struct i915_execbuffer *eb)
 {
-	struct intel_context *ce = eb->context;
-	struct intel_timeline *tl = ce->timeline;
+	struct intel_context *ce = eb->context, *child;
 
 	if (!(eb->args->flags & __EXEC_ENGINE_PINNED))
 		return;
 
 	eb->args->flags &= ~__EXEC_ENGINE_PINNED;
 
-	mutex_lock(&tl->mutex);
+	for_each_child(ce, child) {
+		mutex_lock(&child->timeline->mutex);
+		intel_context_exit(child);
+		mutex_unlock(&child->timeline->mutex);
+
+		intel_context_unpin(child);
+	}
+
+	mutex_lock(&ce->timeline->mutex);
 	intel_context_exit(ce);
-	mutex_unlock(&tl->mutex);
+	mutex_unlock(&ce->timeline->mutex);
 
 	intel_context_unpin(ce);
 }
@@ -2398,7 +2508,7 @@  eb_select_legacy_ring(struct i915_execbuffer *eb)
 static int
 eb_select_engine(struct i915_execbuffer *eb)
 {
-	struct intel_context *ce;
+	struct intel_context *ce, *child;
 	unsigned int idx;
 	int err;
 
@@ -2411,6 +2521,20 @@  eb_select_engine(struct i915_execbuffer *eb)
 	if (IS_ERR(ce))
 		return PTR_ERR(ce);
 
+	if (intel_context_is_parallel(ce)) {
+		if (eb->buffer_count < ce->parallel.number_children + 1) {
+			intel_context_put(ce);
+			return -EINVAL;
+		}
+		if (eb->batch_start_offset || eb->args->batch_len) {
+			intel_context_put(ce);
+			return -EINVAL;
+		}
+	}
+	eb->num_batches = ce->parallel.number_children + 1;
+
+	for_each_child(ce, child)
+		intel_context_get(child);
 	intel_gt_pm_get(ce->engine->gt);
 
 	if (!test_bit(CONTEXT_ALLOC_BIT, &ce->flags)) {
@@ -2418,6 +2542,13 @@  eb_select_engine(struct i915_execbuffer *eb)
 		if (err)
 			goto err;
 	}
+	for_each_child(ce, child) {
+		if (!test_bit(CONTEXT_ALLOC_BIT, &child->flags)) {
+			err = intel_context_alloc_state(child);
+			if (err)
+				goto err;
+		}
+	}
 
 	/*
 	 * ABI: Before userspace accesses the GPU (e.g. execbuffer), report
@@ -2428,7 +2559,7 @@  eb_select_engine(struct i915_execbuffer *eb)
 		goto err;
 
 	eb->context = ce;
-	eb->engine = ce->engine;
+	eb->gt = ce->engine->gt;
 
 	/*
 	 * Make sure engine pool stays alive even if we call intel_context_put
@@ -2439,6 +2570,8 @@  eb_select_engine(struct i915_execbuffer *eb)
 
 err:
 	intel_gt_pm_put(ce->engine->gt);
+	for_each_child(ce, child)
+		intel_context_put(child);
 	intel_context_put(ce);
 	return err;
 }
@@ -2446,7 +2579,11 @@  eb_select_engine(struct i915_execbuffer *eb)
 static void
 eb_put_engine(struct i915_execbuffer *eb)
 {
-	intel_gt_pm_put(eb->engine->gt);
+	struct intel_context *child;
+
+	intel_gt_pm_put(eb->gt);
+	for_each_child(eb->context, child)
+		intel_context_put(child);
 	intel_context_put(eb->context);
 }
 
@@ -2669,7 +2806,8 @@  static void put_fence_array(struct eb_fence *fences, int num_fences)
 }
 
 static int
-await_fence_array(struct i915_execbuffer *eb)
+await_fence_array(struct i915_execbuffer *eb,
+		  struct i915_request *rq)
 {
 	unsigned int n;
 	int err;
@@ -2683,8 +2821,7 @@  await_fence_array(struct i915_execbuffer *eb)
 		if (!eb->fences[n].dma_fence)
 			continue;
 
-		err = i915_request_await_dma_fence(eb->request,
-						   eb->fences[n].dma_fence);
+		err = i915_request_await_dma_fence(rq, eb->fences[n].dma_fence);
 		if (err < 0)
 			return err;
 	}
@@ -2692,9 +2829,9 @@  await_fence_array(struct i915_execbuffer *eb)
 	return 0;
 }
 
-static void signal_fence_array(const struct i915_execbuffer *eb)
+static void signal_fence_array(const struct i915_execbuffer *eb,
+			       struct dma_fence * const fence)
 {
-	struct dma_fence * const fence = &eb->request->fence;
 	unsigned int n;
 
 	for (n = 0; n < eb->num_fences; n++) {
@@ -2742,9 +2879,9 @@  static void retire_requests(struct intel_timeline *tl, struct i915_request *end)
 			break;
 }
 
-static int eb_request_add(struct i915_execbuffer *eb, int err)
+static int eb_request_add(struct i915_execbuffer *eb, struct i915_request *rq,
+			  int err, bool last_parallel)
 {
-	struct i915_request *rq = eb->request;
 	struct intel_timeline * const tl = i915_request_timeline(rq);
 	struct i915_sched_attr attr = {};
 	struct i915_request *prev;
@@ -2766,6 +2903,17 @@  static int eb_request_add(struct i915_execbuffer *eb, int err)
 		err = -ENOENT; /* override any transient errors */
 	}
 
+	if (intel_context_is_parallel(eb->context)) {
+		if (err) {
+			__i915_request_skip(rq);
+			set_bit(I915_FENCE_FLAG_SKIP_PARALLEL,
+				&rq->fence.flags);
+		}
+		if (last_parallel)
+			set_bit(I915_FENCE_FLAG_SUBMIT_PARALLEL,
+				&rq->fence.flags);
+	}
+
 	__i915_request_queue(rq, &attr);
 
 	/* Try to clean up the client's timeline after submitting the request */
@@ -2777,6 +2925,25 @@  static int eb_request_add(struct i915_execbuffer *eb, int err)
 	return err;
 }
 
+static int eb_requests_add(struct i915_execbuffer *eb, int err)
+{
+	int i;
+
+	/*
+	 * We iterate in reverse order of creation to release timeline mutexes in
+	 * same order.
+	 */
+	for_each_batch_add_order(eb, i) {
+		struct i915_request *rq = eb->requests[i];
+
+		if (!rq)
+			continue;
+		err |= eb_request_add(eb, rq, err, i == 0);
+	}
+
+	return err;
+}
+
 static const i915_user_extension_fn execbuf_extensions[] = {
 	[DRM_I915_GEM_EXECBUFFER_EXT_TIMELINE_FENCES] = parse_timeline_fences,
 };
@@ -2803,6 +2970,182 @@  parse_execbuf2_extensions(struct drm_i915_gem_execbuffer2 *args,
 				    eb);
 }
 
+static void eb_requests_get(struct i915_execbuffer *eb)
+{
+	unsigned int i;
+
+	for_each_batch_create_order(eb, i) {
+		if (!eb->requests[i])
+			break;
+
+		i915_request_get(eb->requests[i]);
+	}
+}
+
+static void eb_requests_put(struct i915_execbuffer *eb)
+{
+	unsigned int i;
+
+	for_each_batch_create_order(eb, i) {
+		if (!eb->requests[i])
+			break;
+
+		i915_request_put(eb->requests[i]);
+	}
+}
+
+static struct sync_file *
+eb_composite_fence_create(struct i915_execbuffer *eb, int out_fence_fd)
+{
+	struct sync_file *out_fence = NULL;
+	struct dma_fence_array *fence_array;
+	struct dma_fence **fences;
+	unsigned int i;
+
+	GEM_BUG_ON(!intel_context_is_parent(eb->context));
+
+	fences = kmalloc_array(eb->num_batches, sizeof(*fences), GFP_KERNEL);
+	if (!fences)
+		return ERR_PTR(-ENOMEM);
+
+	for_each_batch_create_order(eb, i)
+		fences[i] = &eb->requests[i]->fence;
+
+	fence_array = dma_fence_array_create(eb->num_batches,
+					     fences,
+					     eb->context->parallel.fence_context,
+					     eb->context->parallel.seqno,
+					     false);
+	if (!fence_array) {
+		kfree(fences);
+		return ERR_PTR(-ENOMEM);
+	}
+
+	/* Move ownership to the dma_fence_array created above */
+	for_each_batch_create_order(eb, i)
+		dma_fence_get(fences[i]);
+
+	if (out_fence_fd != -1) {
+		out_fence = sync_file_create(&fence_array->base);
+		/* sync_file now owns fence_arry, drop creation ref */
+		dma_fence_put(&fence_array->base);
+		if (!out_fence)
+			return ERR_PTR(-ENOMEM);
+	}
+
+	eb->composite_fence = &fence_array->base;
+
+	return out_fence;
+}
+
+static struct sync_file *
+eb_fences_add(struct i915_execbuffer *eb, struct i915_request *rq,
+	      struct dma_fence *in_fence, int out_fence_fd)
+{
+	struct sync_file *out_fence = NULL;
+	int err;
+
+	if (unlikely(eb->gem_context->syncobj)) {
+		struct dma_fence *fence;
+
+		fence = drm_syncobj_fence_get(eb->gem_context->syncobj);
+		err = i915_request_await_dma_fence(rq, fence);
+		dma_fence_put(fence);
+		if (err)
+			return ERR_PTR(err);
+	}
+
+	if (in_fence) {
+		if (eb->args->flags & I915_EXEC_FENCE_SUBMIT)
+			err = i915_request_await_execution(rq, in_fence);
+		else
+			err = i915_request_await_dma_fence(rq, in_fence);
+		if (err < 0)
+			return ERR_PTR(err);
+	}
+
+	if (eb->fences) {
+		err = await_fence_array(eb, rq);
+		if (err)
+			return ERR_PTR(err);
+	}
+
+	if (intel_context_is_parallel(eb->context)) {
+		out_fence = eb_composite_fence_create(eb, out_fence_fd);
+		if (IS_ERR(out_fence))
+			return ERR_PTR(-ENOMEM);
+	} else if (out_fence_fd != -1) {
+		out_fence = sync_file_create(&rq->fence);
+		if (!out_fence)
+			return ERR_PTR(-ENOMEM);
+	}
+
+	return out_fence;
+}
+
+static struct intel_context *
+eb_find_context(struct i915_execbuffer *eb, unsigned int context_number)
+{
+	struct intel_context *child;
+
+	if (likely(context_number == 0))
+		return eb->context;
+
+	for_each_child(eb->context, child)
+		if (!--context_number)
+			return child;
+
+	GEM_BUG_ON("Context not found");
+
+	return NULL;
+}
+
+static struct sync_file *
+eb_requests_create(struct i915_execbuffer *eb, struct dma_fence *in_fence,
+		   int out_fence_fd)
+{
+	struct sync_file *out_fence = NULL;
+	unsigned int i;
+
+	for_each_batch_create_order(eb, i) {
+		/* Allocate a request for this batch buffer nice and early. */
+		eb->requests[i] = i915_request_create(eb_find_context(eb, i));
+		if (IS_ERR(eb->requests[i])) {
+			out_fence = ERR_PTR(PTR_ERR(eb->requests[i]));
+			eb->requests[i] = NULL;
+			return out_fence;
+		}
+
+		/*
+		 * Only the first request added (committed to backend) has to
+		 * take the in fences into account as all subsequent requests
+		 * will have fences inserted inbetween them.
+		 */
+		if (i + 1 == eb->num_batches) {
+			out_fence = eb_fences_add(eb, eb->requests[i],
+						  in_fence, out_fence_fd);
+			if (IS_ERR(out_fence))
+				return out_fence;
+		}
+
+		/*
+		 * Whilst this request exists, batch_obj will be on the
+		 * active_list, and so will hold the active reference. Only when
+		 * this request is retired will the batch_obj be moved onto
+		 * the inactive_list and lose its active reference. Hence we do
+		 * not need to explicitly hold another reference here.
+		 */
+		eb->requests[i]->batch = eb->batches[i]->vma;
+		if (eb->batch_pool) {
+			GEM_BUG_ON(intel_context_is_parallel(eb->context));
+			intel_gt_buffer_pool_mark_active(eb->batch_pool,
+							 eb->requests[i]);
+		}
+	}
+
+	return out_fence;
+}
+
 static int
 i915_gem_do_execbuffer(struct drm_device *dev,
 		       struct drm_file *file,
@@ -2813,7 +3156,6 @@  i915_gem_do_execbuffer(struct drm_device *dev,
 	struct i915_execbuffer eb;
 	struct dma_fence *in_fence = NULL;
 	struct sync_file *out_fence = NULL;
-	struct i915_vma *batch;
 	int out_fence_fd = -1;
 	int err;
 
@@ -2837,12 +3179,15 @@  i915_gem_do_execbuffer(struct drm_device *dev,
 
 	eb.buffer_count = args->buffer_count;
 	eb.batch_start_offset = args->batch_start_offset;
-	eb.batch_len = args->batch_len;
 	eb.trampoline = NULL;
 
 	eb.fences = NULL;
 	eb.num_fences = 0;
 
+	memset(eb.requests, 0, sizeof(struct i915_request *) *
+	       ARRAY_SIZE(eb.requests));
+	eb.composite_fence = NULL;
+
 	eb.batch_flags = 0;
 	if (args->flags & I915_EXEC_SECURE) {
 		if (GRAPHICS_VER(i915) >= 11)
@@ -2926,70 +3271,25 @@  i915_gem_do_execbuffer(struct drm_device *dev,
 
 	ww_acquire_done(&eb.ww.ctx);
 
-	batch = eb.batch->vma;
-
-	/* Allocate a request for this batch buffer nice and early. */
-	eb.request = i915_request_create(eb.context);
-	if (IS_ERR(eb.request)) {
-		err = PTR_ERR(eb.request);
-		goto err_vma;
-	}
-
-	if (unlikely(eb.gem_context->syncobj)) {
-		struct dma_fence *fence;
-
-		fence = drm_syncobj_fence_get(eb.gem_context->syncobj);
-		err = i915_request_await_dma_fence(eb.request, fence);
-		dma_fence_put(fence);
-		if (err)
-			goto err_ext;
-	}
-
-	if (in_fence) {
-		if (args->flags & I915_EXEC_FENCE_SUBMIT)
-			err = i915_request_await_execution(eb.request,
-							   in_fence);
-		else
-			err = i915_request_await_dma_fence(eb.request,
-							   in_fence);
-		if (err < 0)
-			goto err_request;
-	}
-
-	if (eb.fences) {
-		err = await_fence_array(&eb);
-		if (err)
+	out_fence = eb_requests_create(&eb, in_fence, out_fence_fd);
+	if (IS_ERR(out_fence)) {
+		err = PTR_ERR(out_fence);
+		if (eb.requests[0])
 			goto err_request;
+		else
+			goto err_vma;
 	}
 
-	if (out_fence_fd != -1) {
-		out_fence = sync_file_create(&eb.request->fence);
-		if (!out_fence) {
-			err = -ENOMEM;
-			goto err_request;
-		}
-	}
-
-	/*
-	 * Whilst this request exists, batch_obj will be on the
-	 * active_list, and so will hold the active reference. Only when this
-	 * request is retired will the the batch_obj be moved onto the
-	 * inactive_list and lose its active reference. Hence we do not need
-	 * to explicitly hold another reference here.
-	 */
-	eb.request->batch = batch;
-	if (eb.batch_pool)
-		intel_gt_buffer_pool_mark_active(eb.batch_pool, eb.request);
-
-	trace_i915_request_queue(eb.request, eb.batch_flags);
-	err = eb_submit(&eb, batch);
+	err = eb_submit(&eb);
 
 err_request:
-	i915_request_get(eb.request);
-	err = eb_request_add(&eb, err);
+	eb_requests_get(&eb);
+	err = eb_requests_add(&eb, err);
 
 	if (eb.fences)
-		signal_fence_array(&eb);
+		signal_fence_array(&eb, eb.composite_fence ?
+				   eb.composite_fence :
+				   &eb.requests[0]->fence);
 
 	if (out_fence) {
 		if (err == 0) {
@@ -3004,10 +3304,15 @@  i915_gem_do_execbuffer(struct drm_device *dev,
 
 	if (unlikely(eb.gem_context->syncobj)) {
 		drm_syncobj_replace_fence(eb.gem_context->syncobj,
-					  &eb.request->fence);
+					  eb.composite_fence ?
+					  eb.composite_fence :
+					  &eb.requests[0]->fence);
 	}
 
-	i915_request_put(eb.request);
+	if (!out_fence && eb.composite_fence)
+		dma_fence_put(eb.composite_fence);
+
+	eb_requests_put(&eb);
 
 err_vma:
 	eb_release_vmas(&eb, true);
diff --git a/drivers/gpu/drm/i915/gt/intel_context.h b/drivers/gpu/drm/i915/gt/intel_context.h
index 1bc705f98e2a..1781419fa105 100644
--- a/drivers/gpu/drm/i915/gt/intel_context.h
+++ b/drivers/gpu/drm/i915/gt/intel_context.h
@@ -239,7 +239,13 @@  intel_context_timeline_lock(struct intel_context *ce)
 	struct intel_timeline *tl = ce->timeline;
 	int err;
 
-	err = mutex_lock_interruptible(&tl->mutex);
+	if (intel_context_is_parent(ce))
+		err = mutex_lock_interruptible_nested(&tl->mutex, 0);
+	else if (intel_context_is_child(ce))
+		err = mutex_lock_interruptible_nested(&tl->mutex,
+						      ce->parallel.child_index + 1);
+	else
+		err = mutex_lock_interruptible(&tl->mutex);
 	if (err)
 		return ERR_PTR(err);
 
diff --git a/drivers/gpu/drm/i915/gt/intel_context_types.h b/drivers/gpu/drm/i915/gt/intel_context_types.h
index 95a5b94b4ece..9e0177dc5484 100644
--- a/drivers/gpu/drm/i915/gt/intel_context_types.h
+++ b/drivers/gpu/drm/i915/gt/intel_context_types.h
@@ -248,6 +248,16 @@  struct intel_context {
 		 * context
 		 */
 		struct i915_request *last_rq;
+		/**
+		 * @fence_context: fence context composite fence when doing
+		 * parallel submission
+		 */
+		u64 fence_context;
+		/**
+		 * @seqno: seqno for composite fence when doing parallel
+		 * submission
+		 */
+		u32 seqno;
 		/** @number_children: number of children if parent */
 		u8 number_children;
 		/** @child_index: index into child_list if child */
diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
index ae08a196ba0a..bfafe996e2d2 100644
--- a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
+++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
@@ -3099,6 +3099,8 @@  guc_create_parallel(struct intel_engine_cs **engines,
 		}
 	}
 
+	parent->parallel.fence_context = dma_fence_context_alloc(1);
+
 	parent->engine->emit_bb_start =
 		emit_bb_start_parent_no_preempt_mid_batch;
 	parent->engine->emit_fini_breadcrumb =
diff --git a/drivers/gpu/drm/i915/i915_request.h b/drivers/gpu/drm/i915/i915_request.h
index 8950785e55d6..24db8459376b 100644
--- a/drivers/gpu/drm/i915/i915_request.h
+++ b/drivers/gpu/drm/i915/i915_request.h
@@ -147,6 +147,15 @@  enum {
 	 * tail.
 	 */
 	I915_FENCE_FLAG_SUBMIT_PARALLEL,
+
+	/*
+	 * I915_FENCE_FLAG_SKIP_PARALLEL - request with a context in a
+	 * parent-child relationship (parallel submission, multi-lrc) that
+	 * hit an error while generating requests in the execbuf IOCTL.
+	 * Indicates this request should be skipped as another request in
+	 * submission / relationship encoutered an error.
+	 */
+	I915_FENCE_FLAG_SKIP_PARALLEL,
 };
 
 /**
diff --git a/drivers/gpu/drm/i915/i915_vma.c b/drivers/gpu/drm/i915/i915_vma.c
index 4b7fc4647e46..90546fa58fc1 100644
--- a/drivers/gpu/drm/i915/i915_vma.c
+++ b/drivers/gpu/drm/i915/i915_vma.c
@@ -1234,9 +1234,10 @@  int __i915_vma_move_to_active(struct i915_vma *vma, struct i915_request *rq)
 	return i915_active_add_request(&vma->active, rq);
 }
 
-int i915_vma_move_to_active(struct i915_vma *vma,
-			    struct i915_request *rq,
-			    unsigned int flags)
+int _i915_vma_move_to_active(struct i915_vma *vma,
+			     struct i915_request *rq,
+			     struct dma_fence *fence,
+			     unsigned int flags)
 {
 	struct drm_i915_gem_object *obj = vma->obj;
 	int err;
@@ -1257,9 +1258,11 @@  int i915_vma_move_to_active(struct i915_vma *vma,
 			intel_frontbuffer_put(front);
 		}
 
-		dma_resv_add_excl_fence(vma->resv, &rq->fence);
-		obj->write_domain = I915_GEM_DOMAIN_RENDER;
-		obj->read_domains = 0;
+		if (fence) {
+			dma_resv_add_excl_fence(vma->resv, fence);
+			obj->write_domain = I915_GEM_DOMAIN_RENDER;
+			obj->read_domains = 0;
+		}
 	} else {
 		if (!(flags & __EXEC_OBJECT_NO_RESERVE)) {
 			err = dma_resv_reserve_shared(vma->resv, 1);
@@ -1267,8 +1270,10 @@  int i915_vma_move_to_active(struct i915_vma *vma,
 				return err;
 		}
 
-		dma_resv_add_shared_fence(vma->resv, &rq->fence);
-		obj->write_domain = 0;
+		if (fence) {
+			dma_resv_add_shared_fence(vma->resv, fence);
+			obj->write_domain = 0;
+		}
 	}
 
 	if (flags & EXEC_OBJECT_NEEDS_FENCE && vma->fence)
diff --git a/drivers/gpu/drm/i915/i915_vma.h b/drivers/gpu/drm/i915/i915_vma.h
index ed69f66c7ab0..648dbe744c96 100644
--- a/drivers/gpu/drm/i915/i915_vma.h
+++ b/drivers/gpu/drm/i915/i915_vma.h
@@ -57,9 +57,16 @@  static inline bool i915_vma_is_active(const struct i915_vma *vma)
 
 int __must_check __i915_vma_move_to_active(struct i915_vma *vma,
 					   struct i915_request *rq);
-int __must_check i915_vma_move_to_active(struct i915_vma *vma,
-					 struct i915_request *rq,
-					 unsigned int flags);
+int __must_check _i915_vma_move_to_active(struct i915_vma *vma,
+					  struct i915_request *rq,
+					  struct dma_fence *fence,
+					  unsigned int flags);
+static inline int __must_check
+i915_vma_move_to_active(struct i915_vma *vma, struct i915_request *rq,
+			unsigned int flags)
+{
+	return _i915_vma_move_to_active(vma, rq, &rq->fence, flags);
+}
 
 #define __i915_vma_flags(v) ((unsigned long *)&(v)->flags.counter)