Commit 2d838c11 authored by Yishai Hadas's avatar Yishai Hadas Committed by Leon Romanovsky
Browse files

net/mlx5: Add direct ST mode support for RDMA 



Add support for direct ST mode where ST Table Location equals
PCI_TPH_LOC_NONE.

In that case, no steering table exists, the steering tag itself will be
used directly by the SW, FW, HW from the mkey.

This enables RDMA users to use the current exposed APIs to work in
direct mode.

Signed-off-by: default avatarYishai Hadas <yishaih@nvidia.com>
Signed-off-by: default avatarEdward Srouji <edwards@nvidia.com>
Link: https://patch.msgid.link/20251027-st-direct-mode-v1-2-e0ad953866b6@nvidia.com


Signed-off-by: default avatarLeon Romanovsky <leon@kernel.org>
parent 7b8a8ec2

drivers/net/ethernet/mellanox/mlx5/core/lib/st.c

+25 −4
Original line number Diff line number Diff line
@@ -19,13 +19,16 @@ struct mlx5_st { 
	struct mutex lock;

	struct xa_limit index_limit;

	struct xarray idx_xa; /* key == index, value == struct mlx5_st_idx_data */

	u8 direct_mode : 1;

};



struct mlx5_st *mlx5_st_create(struct mlx5_core_dev *dev)

{

	struct pci_dev *pdev = dev->pdev;

	struct mlx5_st *st;

	u8 direct_mode = 0;

	u16 num_entries;

	u32 tbl_loc;

	int ret;



	if (!MLX5_CAP_GEN(dev, mkey_pcie_tph))
@@ -40,10 +43,16 @@ struct mlx5_st *mlx5_st_create(struct mlx5_core_dev *dev) 
	if (!pdev->tph_cap)

		return NULL;



	tbl_loc = pcie_tph_get_st_table_loc(pdev);

	if (tbl_loc == PCI_TPH_LOC_NONE)

		direct_mode = 1;



	if (!direct_mode) {

		num_entries = pcie_tph_get_st_table_size(pdev);

		/* We need a reserved entry for non TPH cases */

		if (num_entries < 2)

			return NULL;

	}



	/* The OS doesn't support ST */

	ret = pcie_enable_tph(pdev, PCI_TPH_ST_DS_MODE);
@@ -56,6 +65,10 @@ struct mlx5_st *mlx5_st_create(struct mlx5_core_dev *dev) 


	mutex_init(&st->lock);

	xa_init_flags(&st->idx_xa, XA_FLAGS_ALLOC);

	st->direct_mode = direct_mode;

	if (st->direct_mode)

		return st;



	/* entry 0 is reserved for non TPH cases */

	st->index_limit.min = MLX5_MKC_PCIE_TPH_NO_STEERING_TAG_INDEX + 1;

	st->index_limit.max = num_entries - 1;
@@ -96,6 +109,11 @@ int mlx5_st_alloc_index(struct mlx5_core_dev *dev, enum tph_mem_type mem_type, 
	if (ret)

		return ret;



	if (st->direct_mode) {

		*st_index = tag;

		return 0;

	}



	mutex_lock(&st->lock);



	xa_for_each(&st->idx_xa, index, idx_data) {
@@ -145,6 +163,9 @@ int mlx5_st_dealloc_index(struct mlx5_core_dev *dev, u16 st_index) 
	if (!st)

		return -EOPNOTSUPP;



	if (st->direct_mode)

		return 0;



	mutex_lock(&st->lock);

	idx_data = xa_load(&st->idx_xa, st_index);

	if (WARN_ON_ONCE(!idx_data)) {