Commit 01e035fd authored by Yevgeny Kliteynik's avatar Yevgeny Kliteynik Committed by Jakub Kicinski
Browse files

net/mlx5: HWS, handle modify header actions dependency 



Having adjacent accelerated modify header actions (so-called
pattern-argument actions) may result in inconsistent outcome.
These inconsistencies can take the form of writes to the same
field or a read coupled with a write to the same field. The
solution is to detect such dependencies and insert nops between
the offending actions.

The existing implementation had a few issues, which pretty much
required a complete rewrite of the code that handles these
dependencies.

In the new implementation we're doing the following:

* Checking any two adjacent actions for conflicts (not just
  odd-even pairs).
* Marking 'set' and 'add' action fields as destination, rather
  than source, for the purposes of checking for conflicts.
* Checking all types of actions ('add', 'set', 'copy') for
  dependencies.
* Managing offsets of the args in the buffer - copy the action
  args to the right place in the buffer.
* Checking that after inserting nops we're still within the number
  of supported actions - return an error otherwise.

Signed-off-by: default avatarVlad Dogaru <vdogaru@nvidia.com>
Signed-off-by: default avatarYevgeny Kliteynik <kliteyn@nvidia.com>
Reviewed-by: default avatarMark Bloch <mbloch@nvidia.com>
Signed-off-by: default avatarTariq Toukan <tariqt@nvidia.com>
Link: https://patch.msgid.link/1747766802-958178-5-git-send-email-tariqt@nvidia.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 0b6e452c

drivers/net/ethernet/mellanox/mlx5/core/steering/hws/action.c

+14 −7
Original line number Diff line number Diff line
@@ -1190,14 +1190,15 @@ hws_action_create_modify_header_hws(struct mlx5hws_action *action, 
				    struct mlx5hws_action_mh_pattern *pattern,

				    u32 log_bulk_size)

{

	u16 num_actions, max_mh_actions = 0, hw_max_actions;

	struct mlx5hws_context *ctx = action->ctx;

	u16 num_actions, max_mh_actions = 0;

	int i, ret, size_in_bytes;

	u32 pat_id, arg_id = 0;

	__be64 *new_pattern;

	size_t pat_max_sz;



	pat_max_sz = MLX5HWS_ARG_CHUNK_SIZE_MAX * MLX5HWS_ARG_DATA_SIZE;

	hw_max_actions = pat_max_sz / MLX5HWS_MODIFY_ACTION_SIZE;

	size_in_bytes = pat_max_sz * sizeof(__be64);

	new_pattern = kcalloc(num_of_patterns, size_in_bytes, GFP_KERNEL);

	if (!new_pattern)
@@ -1211,10 +1212,14 @@ hws_action_create_modify_header_hws(struct mlx5hws_action *action, 


		cur_num_actions = pattern[i].sz / MLX5HWS_MODIFY_ACTION_SIZE;



		mlx5hws_pat_calc_nop(pattern[i].data, cur_num_actions,

				     pat_max_sz / MLX5HWS_MODIFY_ACTION_SIZE,

				     &new_num_actions, &nop_locations,

		ret = mlx5hws_pat_calc_nop(pattern[i].data, cur_num_actions,

					   hw_max_actions, &new_num_actions,

					   &nop_locations,

					   &new_pattern[i * pat_max_sz]);

		if (ret) {

			mlx5hws_err(ctx, "Too many actions after nop insertion\n");

			goto free_new_pat;

		}



		action[i].modify_header.nop_locations = nop_locations;

		action[i].modify_header.num_of_actions = new_num_actions;
@@ -2116,10 +2121,12 @@ static void hws_action_modify_write(struct mlx5hws_send_engine *queue, 
		if (unlikely(!new_arg_data))

			return;



		for (i = 0, j = 0; i < num_of_actions; i++, j++) {

			memcpy(&new_arg_data[j], arg_data, MLX5HWS_MODIFY_ACTION_SIZE);

		for (i = 0, j = 0; j < num_of_actions; i++, j++) {

			if (BIT(i) & nop_locations)

				j++;

			memcpy(&new_arg_data[j * MLX5HWS_MODIFY_ACTION_SIZE],

			       &arg_data[i * MLX5HWS_MODIFY_ACTION_SIZE],

			       MLX5HWS_MODIFY_ACTION_SIZE);

		}

	}

drivers/net/ethernet/mellanox/mlx5/core/steering/hws/pat_arg.c

+38 −36
Original line number Diff line number Diff line
@@ -490,8 +490,8 @@ hws_action_modify_get_target_fields(u8 action_type, __be64 *pattern, 
	switch (action_type) {

	case MLX5_ACTION_TYPE_SET:

	case MLX5_ACTION_TYPE_ADD:

		*src_field = MLX5_GET(set_action_in, pattern, field);

		*dst_field = INVALID_FIELD;

		*src_field = INVALID_FIELD;

		*dst_field = MLX5_GET(set_action_in, pattern, field);

		break;

	case MLX5_ACTION_TYPE_COPY:

		*src_field = MLX5_GET(copy_action_in, pattern, src_field);
@@ -522,57 +522,59 @@ bool mlx5hws_pat_verify_actions(struct mlx5hws_context *ctx, __be64 pattern[], s 
	return true;

}



void mlx5hws_pat_calc_nop(__be64 *pattern, size_t num_actions,

int mlx5hws_pat_calc_nop(__be64 *pattern, size_t num_actions,

			 size_t max_actions, size_t *new_size,

			 u32 *nop_locations, __be64 *new_pat)

{

	u16 prev_src_field = 0, prev_dst_field = 0;

	u16 prev_src_field = INVALID_FIELD, prev_dst_field = INVALID_FIELD;

	u16 src_field, dst_field;

	u8 action_type;

	bool dependent;

	size_t i, j;



	*new_size = num_actions;

	*nop_locations = 0;



	if (num_actions == 1)

		return;

		return 0;



	for (i = 0, j = 0; i < num_actions; i++, j++) {

		action_type = MLX5_GET(set_action_in, &pattern[i], action_type);

		if (j >= max_actions)

			return -EINVAL;



		action_type = MLX5_GET(set_action_in, &pattern[i], action_type);

		hws_action_modify_get_target_fields(action_type, &pattern[i],

						    &src_field, &dst_field);

		if (i % 2) {

			if (action_type == MLX5_ACTION_TYPE_COPY &&

			    (prev_src_field == src_field ||

			     prev_dst_field == dst_field)) {

				/* need Nop */



		/* For every action, look at it and the previous one. The two

		 * actions are dependent if:

		 */

		dependent =

			(i > 0) &&

			/* At least one of the actions is a write and */

			(dst_field != INVALID_FIELD ||

			 prev_dst_field != INVALID_FIELD) &&

			/* One reads from the other's source */

			(dst_field == prev_src_field ||

			 src_field == prev_dst_field ||

			 /* Or both write to the same destination */

			 dst_field == prev_dst_field);



		if (dependent) {

			*new_size += 1;

			*nop_locations |= BIT(i);

			memset(&new_pat[j], 0, MLX5HWS_MODIFY_ACTION_SIZE);

				MLX5_SET(set_action_in, &new_pat[j],

					 action_type,

					 MLX5_MODIFICATION_TYPE_NOP);

				j++;

			} else if (prev_src_field == src_field) {

				/* need Nop */

				*new_size += 1;

				*nop_locations |= BIT(i);

				MLX5_SET(set_action_in, &new_pat[j],

					 action_type,

			MLX5_SET(set_action_in, &new_pat[j], action_type,

				 MLX5_MODIFICATION_TYPE_NOP);

			j++;

			}

		}

		memcpy(&new_pat[j], &pattern[i], MLX5HWS_MODIFY_ACTION_SIZE);

		/* check if no more space */

		if (j > max_actions) {

			*new_size = num_actions;

			*nop_locations = 0;

			return;

			if (j >= max_actions)

				return -EINVAL;

		}



		memcpy(&new_pat[j], &pattern[i], MLX5HWS_MODIFY_ACTION_SIZE);

		prev_src_field = src_field;

		prev_dst_field = dst_field;

	}



	return 0;

}

drivers/net/ethernet/mellanox/mlx5/core/steering/hws/pat_arg.h

+3 −3
Original line number Diff line number Diff line
@@ -96,7 +96,7 @@ int mlx5hws_arg_write_inline_arg_data(struct mlx5hws_context *ctx, 
				      u8 *arg_data,

				      size_t data_size);



void mlx5hws_pat_calc_nop(__be64 *pattern, size_t num_actions,

int mlx5hws_pat_calc_nop(__be64 *pattern, size_t num_actions,

			 size_t max_actions, size_t *new_size,

			 u32 *nop_locations, __be64 *new_pat);

#endif /* MLX5HWS_PAT_ARG_H_ */