Merge branch 'bnxt_en-implement-tcp-data-split-and-thresh-option'

Taehee Yoo says:

====================
bnxt_en: implement tcp-data-split and thresh option

This series implements hds-thresh ethtool command.
This series also implements backend of tcp-data-split and
hds-thresh ethtool command for bnxt_en driver.
These ethtool commands are mandatory options for device memory TCP.

NICs that use the bnxt_en driver support tcp-data-split feature named
HDS(header-data-split).
But there is no implementation for the HDS to enable by ethtool.
Only getting the current HDS status is implemented and the HDS is just
automatically enabled only when either LRO, HW-GRO, or JUMBO is enabled.
The hds_threshold follows the rx-copybreak value but it wasn't
changeable.

Currently, bnxt_en driver enables tcp-data-split by default but not
always work.
There is hds_threshold value, which indicates that a packet size is
larger than this value, a packet will be split into header and data.
hds_threshold value has been 256, which is a default value of
rx-copybreak value too.
The rx-copybreak value hasn't been allowed to change so the
hds_threshold too.

This patchset decouples hds_threshold and rx-copybreak first.
and make tcp-data-split, rx-copybreak, and
hds-thresh configurable independently.

But the default configuration is the same.
The default value of rx-copybreak is 256 and default
hds-thresh is also 256.

The behavior of rx-copybreak will probably be changed in almost all
drivers. If HDS is not enabled, rx-copybreak copies both header and
payload from a page.
But if HDS is enabled, rx-copybreak copies only header from the first
page.
Due to this change, it may need to disable(set to 0) rx-copybreak when
the HDS is required.

There are several related options.
TPA(HW-GRO, LRO), JUMBO, jumbo_thresh(firmware command), and Aggregation
Ring.

The aggregation ring is fundamental to these all features.
When gro/lro/jumbo packets are received, NIC receives the first packet
from the normal ring.
follow packets come from the aggregation ring.

These features are working regardless of HDS.
If HDS is enabled, the first packet contains the header only, and the
following packets contain only payload.
So, HW-GRO/LRO is working regardless of HDS.

There is another threshold value, which is jumbo_thresh.
This is very similar to hds_thresh, but jumbo thresh doesn't split
header and data.
It just split the first and following data based on length.
When NIC receives 1500 sized packet, and jumbo_thresh is 256(default, but
follows rx-copybreak),
the first data is 256 and the following packet size is 1500-256.

Before this patch, at least if one of GRO, LRO, and JUMBO flags is
enabled, the Aggregation ring will be enabled.
If the Aggregation ring is enabled, both hds_threshold and
jumbo_thresh are set to the default value of rx-copybreak.

So, GRO, LRO, JUMBO frames, they larger than 256 bytes, they will
be split into header and data if the protocol is TCP or UDP.
for the other protocol, jumbo_thresh works instead of hds_thresh.

This means that tcp-data-split relies on the GRO, LRO, and JUMBO flags.
But by this patch, tcp-data-split no longer relies on these flags.
If the tcp-data-split is enabled, the Aggregation ring will be
enabled.
Also, hds_threshold no longer follows rx-copybreak value, it will
be set to the hds-thresh value by user-space, but the
default value is still 256.

If the protocol is TCP or UDP and the HDS is disabled and Aggregation
ring is enabled, a packet will be split into several pieces due to
jumbo_thresh.

When single buffer XDP is attached, tcp-data-split is automatically
disabled.

LRO, GRO, and JUMBO are tested with BCM57414, BCM57504 and the firmware
version is 230.0.157.0.
I couldn't find any specification about minimum and maximum value
of hds_threshold, but from my test result, it was about 0 ~ 1023.
It means, over 1023 sized packets will be split into header and data if
tcp-data-split is enabled regardless of hds_treshold value.
When hds_threshold is 1500 and received packet size is 1400, HDS should
not be activated, but it is activated.
The maximum value of hds-thresh value is 256 because it
has been working. It was decided very conservatively.

I checked out the tcp-data-split(HDS) works independently of GRO, LRO,
JUMBO.
Also, I checked out tcp-data-split should be disabled automatically
when XDP is attached and disallowed to enable it again while XDP is
attached. I tested ranged values from min to max for
hds-thresh and rx-copybreak, and it works.
hds-thresh from 0 to 256, and rx-copybreak 0 to 256.
When testing this patchset, I checked skb->data, skb->data_len, and
nr_frags values.

By this patchset, bnxt_en driver supports a force enable tcp-data-split,
but it doesn't support for disable tcp-data-split.
When tcp-data-split is explicitly enabled, HDS works always.
When tcp-data-split is unknown, it depends on the current
configuration of LRO/GRO/JUMBO.

1/10 patch adds a new hds_config member in the ethtool_netdev_state.
It indicates that what tcp-data-split value is really updated from
userspace.
So the driver can distinguish a passed tcp-data-split value is
came from user or driver itself.

2/10 patch adds hds-thresh command in the ethtool.
This threshold value indicates if a received packet size is larger
than this threshold, the packet's header and payload will be split.
Example:
   # ethtool -G <interface name> hds-thresh <value>
This option can not be used when tcp-data-split is disabled or not
supported.
   # ethtool -G enp14s0f0np0 tcp-data-split on hds-thresh 256
   # ethtool -g enp14s0f0np0
   Ring parameters for enp14s0f0np0:
   Pre-set maximums:
   ...
   Current hardware settings:
   ...
   TCP data split:         on
   HDS thresh:  256

3/10, 4/10 add condition checks for devmem and ethtool.
If tcp-data-split is disabled or threshold value is not zero, setup of
devmem will be failed.
Also, tcp-data-split and hds-thresh will not be changed
while devmem is running.

5/10 add condition checks for netdev core.
It disallows setup single buffer XDP program when tcp-data-split is
enabled.

6/10 patch implements .{set, get}_tunable() in the bnxt_en.
The bnxt_en driver has been supporting the rx-copybreak feature but is
not configurable, Only the default rx-copybreak value has been working.
So, it changes the bnxt_en driver to be able to configure
the rx-copybreak value.

7/10 patch adds an implementation of tcp-data-split ethtool
command.
The HDS relies on the Aggregation ring, which is automatically enabled
when either LRO, GRO, or large mtu is configured.
So, if the Aggregation ring is enabled, HDS is automatically enabled by
it.

8/10 patch adds the implementation of hds-thresh logic
in the bnxt_en driver.
The default value is 256, which used to be the default rx-copybreak
value.

9/10 add HDS feature implementation for netdevsim.
HDS feature is not common so far. Only a few NICs support this feature.
There is no way to test HDS core-API unless we have proper hw NIC.
In order to test HDS core-API without  hw NIC, netdevsim can be used.
It implements HDS control and data plane for netdevsim.

10/10 add selftest for HDS(tcp-data-split and HDS-thresh).
The tcp-data-split tests are the same with
`ethtool -G tcp-data-split <on | auto>`
HDS-thresh tests are same with `ethtool -G eth0 hds-thresh <0 - MAX>`

This series is tested with BCM57504 and netdevsim.
====================

Link: https://patch.msgid.link/20250114142852.3364986-1-ap420073@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

18 files changed, 363 insertions, 21 deletions

diff --git a/Documentation/netlink/specs/ethtool.yaml b/Documentation/netlink/specs/ethtool.yaml
index 60f85fbf4156..66be04013048 100644
--- a/Documentation/netlink/specs/ethtool.yaml
+++ b/Documentation/netlink/specs/ethtool.yaml
@@ -332,6 +332,12 @@ attribute-sets:
       -
         name: tx-push-buf-len-max
         type: u32
+      -
+        name: hds-thresh
+        type: u32
+      -
+        name: hds-thresh-max
+        type: u32
 
   -
     name: mm-stat
@@ -1777,6 +1783,8 @@ operations:
             - rx-push
             - tx-push-buf-len
             - tx-push-buf-len-max
+            - hds-thresh
+            - hds-thresh-max
       dump: *ring-get-op
     -
       name: rings-set
diff --git a/Documentation/networking/ethtool-netlink.rst b/Documentation/networking/ethtool-netlink.rst
index da846f1d998e..f70c0249860c 100644
--- a/Documentation/networking/ethtool-netlink.rst
+++ b/Documentation/networking/ethtool-netlink.rst
@@ -899,6 +899,10 @@ Kernel response contents:
   ``ETHTOOL_A_RINGS_RX_PUSH``               u8      flag of RX Push mode
   ``ETHTOOL_A_RINGS_TX_PUSH_BUF_LEN``       u32     size of TX push buffer
   ``ETHTOOL_A_RINGS_TX_PUSH_BUF_LEN_MAX``   u32     max size of TX push buffer
+  ``ETHTOOL_A_RINGS_HDS_THRESH``            u32     threshold of
+                                                    header / data split
+  ``ETHTOOL_A_RINGS_HDS_THRESH_MAX``        u32     max threshold of
+                                                    header / data split
   =======================================   ======  ===========================
 
 ``ETHTOOL_A_RINGS_TCP_DATA_SPLIT`` indicates whether the device is usable with
@@ -941,10 +945,12 @@ Request contents:
   ``ETHTOOL_A_RINGS_RX_JUMBO``          u32     size of RX jumbo ring
   ``ETHTOOL_A_RINGS_TX``                u32     size of TX ring
   ``ETHTOOL_A_RINGS_RX_BUF_LEN``        u32     size of buffers on the ring
+  ``ETHTOOL_A_RINGS_TCP_DATA_SPLIT``    u8      TCP header / data split
   ``ETHTOOL_A_RINGS_CQE_SIZE``          u32     Size of TX/RX CQE
   ``ETHTOOL_A_RINGS_TX_PUSH``           u8      flag of TX Push mode
   ``ETHTOOL_A_RINGS_RX_PUSH``           u8      flag of RX Push mode
   ``ETHTOOL_A_RINGS_TX_PUSH_BUF_LEN``   u32     size of TX push buffer
+  ``ETHTOOL_A_RINGS_HDS_THRESH``        u32     threshold of header / data split
   ====================================  ======  ===========================
 
 Kernel checks that requested ring sizes do not exceed limits reported by
@@ -961,6 +967,10 @@ A bigger CQE can have more receive buffer pointers, and in turn the NIC can
 transfer a bigger frame from wire. Based on the NIC hardware, the overall
 completion queue size can be adjusted in the driver if CQE size is modified.
 
+``ETHTOOL_A_RINGS_HDS_THRESH`` specifies the threshold value of
+header / data split feature. If a received packet size is larger than this
+threshold value, header and data will be split.
+
 CHANNELS_GET
 ============
 
diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt.c b/drivers/net/ethernet/broadcom/bnxt/bnxt.c
index 884d42db5554..caddb5cbc024 100644
--- a/drivers/net/ethernet/broadcom/bnxt/bnxt.c
+++ b/drivers/net/ethernet/broadcom/bnxt/bnxt.c
@@ -81,7 +81,6 @@ MODULE_DESCRIPTION("Broadcom NetXtreme network driver");
 
 #define BNXT_RX_OFFSET (NET_SKB_PAD + NET_IP_ALIGN)
 #define BNXT_RX_DMA_OFFSET NET_SKB_PAD
-#define BNXT_RX_COPY_THRESH 256
 
 #define BNXT_TX_PUSH_THRESH 164
 
@@ -1343,13 +1342,13 @@ static struct sk_buff *bnxt_copy_data(struct bnxt_napi *bnapi, u8 *data,
 	if (!skb)
 		return NULL;
 
-	dma_sync_single_for_cpu(&pdev->dev, mapping, bp->rx_copy_thresh,
+	dma_sync_single_for_cpu(&pdev->dev, mapping, bp->rx_copybreak,
 				bp->rx_dir);
 
 	memcpy(skb->data - NET_IP_ALIGN, data - NET_IP_ALIGN,
 	       len + NET_IP_ALIGN);
 
-	dma_sync_single_for_device(&pdev->dev, mapping, bp->rx_copy_thresh,
+	dma_sync_single_for_device(&pdev->dev, mapping, bp->rx_copybreak,
 				   bp->rx_dir);
 
 	skb_put(skb, len);
@@ -1842,7 +1841,7 @@ static inline struct sk_buff *bnxt_tpa_end(struct bnxt *bp,
 		return NULL;
 	}
 
-	if (len <= bp->rx_copy_thresh) {
+	if (len <= bp->rx_copybreak) {
 		skb = bnxt_copy_skb(bnapi, data_ptr, len, mapping);
 		if (!skb) {
 			bnxt_abort_tpa(cpr, idx, agg_bufs);
@@ -2176,7 +2175,7 @@ static int bnxt_rx_pkt(struct bnxt *bp, struct bnxt_cp_ring_info *cpr,
 		}
 	}
 
-	if (len <= bp->rx_copy_thresh) {
+	if (len <= bp->rx_copybreak) {
 		if (!xdp_active)
 			skb = bnxt_copy_skb(bnapi, data_ptr, len, dma_addr);
 		else
@@ -4608,6 +4607,12 @@ void bnxt_set_tpa_flags(struct bnxt *bp)
 		bp->flags |= BNXT_FLAG_GRO;
 }
 
+static void bnxt_init_ring_params(struct bnxt *bp)
+{
+	bp->rx_copybreak = BNXT_DEFAULT_RX_COPYBREAK;
+	bp->dev->ethtool->hds_thresh = BNXT_DEFAULT_RX_COPYBREAK;
+}
+
 /* bp->rx_ring_size, bp->tx_ring_size, dev->mtu, BNXT_FLAG_{G|L}RO flags must
  * be set on entry.
  */
@@ -4622,12 +4627,11 @@ void bnxt_set_ring_params(struct bnxt *bp)
 	rx_space = rx_size + ALIGN(max(NET_SKB_PAD, XDP_PACKET_HEADROOM), 8) +
 		SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
 
-	bp->rx_copy_thresh = BNXT_RX_COPY_THRESH;
 	ring_size = bp->rx_ring_size;
 	bp->rx_agg_ring_size = 0;
 	bp->rx_agg_nr_pages = 0;
 
-	if (bp->flags & BNXT_FLAG_TPA)
+	if (bp->flags & BNXT_FLAG_TPA || bp->flags & BNXT_FLAG_HDS)
 		agg_factor = min_t(u32, 4, 65536 / BNXT_RX_PAGE_SIZE);
 
 	bp->flags &= ~BNXT_FLAG_JUMBO;
@@ -4667,7 +4671,9 @@ void bnxt_set_ring_params(struct bnxt *bp)
 				  ALIGN(max(NET_SKB_PAD, XDP_PACKET_HEADROOM), 8) -
 				  SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
 		} else {
-			rx_size = SKB_DATA_ALIGN(BNXT_RX_COPY_THRESH + NET_IP_ALIGN);
+			rx_size = SKB_DATA_ALIGN(max(BNXT_DEFAULT_RX_COPYBREAK,
+						     bp->rx_copybreak) +
+						 NET_IP_ALIGN);
 			rx_space = rx_size + NET_SKB_PAD +
 				SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
 		}
@@ -6564,6 +6570,7 @@ static void bnxt_hwrm_update_rss_hash_cfg(struct bnxt *bp)
 
 static int bnxt_hwrm_vnic_set_hds(struct bnxt *bp, struct bnxt_vnic_info *vnic)
 {
+	u16 hds_thresh = (u16)bp->dev->ethtool->hds_thresh;
 	struct hwrm_vnic_plcmodes_cfg_input *req;
 	int rc;
 
@@ -6573,16 +6580,14 @@ static int bnxt_hwrm_vnic_set_hds(struct bnxt *bp, struct bnxt_vnic_info *vnic)
 
 	req->flags = cpu_to_le32(VNIC_PLCMODES_CFG_REQ_FLAGS_JUMBO_PLACEMENT);
 	req->enables = cpu_to_le32(VNIC_PLCMODES_CFG_REQ_ENABLES_JUMBO_THRESH_VALID);
+	req->jumbo_thresh = cpu_to_le16(bp->rx_buf_use_size);
 
-	if (BNXT_RX_PAGE_MODE(bp)) {
-		req->jumbo_thresh = cpu_to_le16(bp->rx_buf_use_size);
-	} else {
+	if (!BNXT_RX_PAGE_MODE(bp) && (bp->flags & BNXT_FLAG_AGG_RINGS)) {
 		req->flags |= cpu_to_le32(VNIC_PLCMODES_CFG_REQ_FLAGS_HDS_IPV4 |
 					  VNIC_PLCMODES_CFG_REQ_FLAGS_HDS_IPV6);
 		req->enables |=
 			cpu_to_le32(VNIC_PLCMODES_CFG_REQ_ENABLES_HDS_THRESHOLD_VALID);
-		req->jumbo_thresh = cpu_to_le16(bp->rx_copy_thresh);
-		req->hds_threshold = cpu_to_le16(bp->rx_copy_thresh);
+		req->hds_threshold = cpu_to_le16(hds_thresh);
 	}
 	req->vnic_id = cpu_to_le32(vnic->fw_vnic_id);
 	return hwrm_req_send(bp, req);
@@ -16261,6 +16266,7 @@ static int bnxt_init_one(struct pci_dev *pdev, const struct pci_device_id *ent)
 	bnxt_init_l2_fltr_tbl(bp);
 	bnxt_set_rx_skb_mode(bp, false);
 	bnxt_set_tpa_flags(bp);
+	bnxt_init_ring_params(bp);
 	bnxt_set_ring_params(bp);
 	bnxt_rdma_aux_device_init(bp);
 	rc = bnxt_set_dflt_rings(bp, true);
diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt.h b/drivers/net/ethernet/broadcom/bnxt/bnxt.h
index 094c9e95b463..8f481dd9c224 100644
--- a/drivers/net/ethernet/broadcom/bnxt/bnxt.h
+++ b/drivers/net/ethernet/broadcom/bnxt/bnxt.h
@@ -34,6 +34,9 @@
 #include <linux/firmware/broadcom/tee_bnxt_fw.h>
 #endif
 
+#define BNXT_DEFAULT_RX_COPYBREAK 256
+#define BNXT_MAX_RX_COPYBREAK 1024
+
 extern struct list_head bnxt_block_cb_list;
 
 struct page_pool;
@@ -2241,8 +2244,6 @@ struct bnxt {
 	#define BNXT_FLAG_TPA		(BNXT_FLAG_LRO | BNXT_FLAG_GRO)
 	#define BNXT_FLAG_JUMBO		0x10
 	#define BNXT_FLAG_STRIP_VLAN	0x20
-	#define BNXT_FLAG_AGG_RINGS	(BNXT_FLAG_JUMBO | BNXT_FLAG_GRO | \
-					 BNXT_FLAG_LRO)
 	#define BNXT_FLAG_RFS		0x100
 	#define BNXT_FLAG_SHARED_RINGS	0x200
 	#define BNXT_FLAG_PORT_STATS	0x400
@@ -2263,6 +2264,9 @@ struct bnxt {
 	#define BNXT_FLAG_ROCE_MIRROR_CAP	0x4000000
 	#define BNXT_FLAG_TX_COAL_CMPL	0x8000000
 	#define BNXT_FLAG_PORT_STATS_EXT	0x10000000
+	#define BNXT_FLAG_HDS		0x20000000
+	#define BNXT_FLAG_AGG_RINGS	(BNXT_FLAG_JUMBO | BNXT_FLAG_GRO | \
+					 BNXT_FLAG_LRO | BNXT_FLAG_HDS)
 
 	#define BNXT_FLAG_ALL_CONFIG_FEATS (BNXT_FLAG_TPA |		\
 					    BNXT_FLAG_RFS |		\
@@ -2347,7 +2351,7 @@ struct bnxt {
 	enum dma_data_direction	rx_dir;
 	u32			rx_ring_size;
 	u32			rx_agg_ring_size;
-	u32			rx_copy_thresh;
+	u32			rx_copybreak;
 	u32			rx_ring_mask;
 	u32			rx_agg_ring_mask;
 	int			rx_nr_pages;
@@ -2775,6 +2779,8 @@ struct bnxt {
 #define SFF_MODULE_ID_QSFP28			0x11
 #define BNXT_MAX_PHY_I2C_RESP_SIZE		64
 
+#define BNXT_HDS_THRESHOLD_MAX			1023
+
 static inline u32 bnxt_tx_avail(struct bnxt *bp,
 				const struct bnxt_tx_ring_info *txr)
 {
diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt_ethtool.c b/drivers/net/ethernet/broadcom/bnxt/bnxt_ethtool.c
index 75a59dd72bce..540c140d52dc 100644
--- a/drivers/net/ethernet/broadcom/bnxt/bnxt_ethtool.c
+++ b/drivers/net/ethernet/broadcom/bnxt/bnxt_ethtool.c
@@ -833,6 +833,9 @@ static void bnxt_get_ringparam(struct net_device *dev,
 	ering->rx_pending = bp->rx_ring_size;
 	ering->rx_jumbo_pending = bp->rx_agg_ring_size;
 	ering->tx_pending = bp->tx_ring_size;
+
+	kernel_ering->hds_thresh = dev->ethtool->hds_thresh;
+	kernel_ering->hds_thresh_max = BNXT_HDS_THRESHOLD_MAX;
 }
 
 static int bnxt_set_ringparam(struct net_device *dev,
@@ -840,16 +843,35 @@ static int bnxt_set_ringparam(struct net_device *dev,
 			      struct kernel_ethtool_ringparam *kernel_ering,
 			      struct netlink_ext_ack *extack)
 {
+	u8 tcp_data_split = kernel_ering->tcp_data_split;
 	struct bnxt *bp = netdev_priv(dev);
+	u8 hds_config_mod;
 
 	if ((ering->rx_pending > BNXT_MAX_RX_DESC_CNT) ||
 	    (ering->tx_pending > BNXT_MAX_TX_DESC_CNT) ||
 	    (ering->tx_pending < BNXT_MIN_TX_DESC_CNT))
 		return -EINVAL;
 
+	hds_config_mod = tcp_data_split != dev->ethtool->hds_config;
+	if (tcp_data_split == ETHTOOL_TCP_DATA_SPLIT_DISABLED && hds_config_mod)
+		return -EINVAL;
+
+	if (tcp_data_split == ETHTOOL_TCP_DATA_SPLIT_ENABLED &&
+	    hds_config_mod && BNXT_RX_PAGE_MODE(bp)) {
+		NL_SET_ERR_MSG_MOD(extack, "tcp-data-split is disallowed when XDP is attached");
+		return -EINVAL;
+	}
+
 	if (netif_running(dev))
 		bnxt_close_nic(bp, false, false);
 
+	if (hds_config_mod) {
+		if (tcp_data_split == ETHTOOL_TCP_DATA_SPLIT_ENABLED)
+			bp->flags |= BNXT_FLAG_HDS;
+		else if (tcp_data_split == ETHTOOL_TCP_DATA_SPLIT_UNKNOWN)
+			bp->flags &= ~BNXT_FLAG_HDS;
+	}
+
 	bp->rx_ring_size = ering->rx_pending;
 	bp->tx_ring_size = ering->tx_pending;
 	bnxt_set_ring_params(bp);
@@ -4328,6 +4350,45 @@ static int bnxt_get_eee(struct net_device *dev, struct ethtool_keee *edata)
 	return 0;
 }
 
+static int bnxt_set_tunable(struct net_device *dev,
+			    const struct ethtool_tunable *tuna,
+			    const void *data)
+{
+	struct bnxt *bp = netdev_priv(dev);
+	u32 rx_copybreak;
+
+	switch (tuna->id) {
+	case ETHTOOL_RX_COPYBREAK:
+		rx_copybreak = *(u32 *)data;
+		if (rx_copybreak > BNXT_MAX_RX_COPYBREAK)
+			return -ERANGE;
+		if (rx_copybreak != bp->rx_copybreak) {
+			if (netif_running(dev))
+				return -EBUSY;
+			bp->rx_copybreak = rx_copybreak;
+		}
+		return 0;
+	default:
+		return -EOPNOTSUPP;
+	}
+}
+
+static int bnxt_get_tunable(struct net_device *dev,
+			    const struct ethtool_tunable *tuna, void *data)
+{
+	struct bnxt *bp = netdev_priv(dev);
+
+	switch (tuna->id) {
+	case ETHTOOL_RX_COPYBREAK:
+		*(u32 *)data = bp->rx_copybreak;
+		break;
+	default:
+		return -EOPNOTSUPP;
+	}
+
+	return 0;
+}
+
 static int bnxt_read_sfp_module_eeprom_info(struct bnxt *bp, u16 i2c_addr,
 					    u16 page_number, u8 bank,
 					    u16 start_addr, u16 data_length,
@@ -4790,7 +4851,8 @@ static int bnxt_run_loopback(struct bnxt *bp)
 	cpr = &rxr->bnapi->cp_ring;
 	if (bp->flags & BNXT_FLAG_CHIP_P5_PLUS)
 		cpr = rxr->rx_cpr;
-	pkt_size = min(bp->dev->mtu + ETH_HLEN, bp->rx_copy_thresh);
+	pkt_size = min(bp->dev->mtu + ETH_HLEN, max(BNXT_DEFAULT_RX_COPYBREAK,
+						    bp->rx_copybreak));
 	skb = netdev_alloc_skb(bp->dev, pkt_size);
 	if (!skb)
 		return -ENOMEM;
@@ -5331,6 +5393,8 @@ const struct ethtool_ops bnxt_ethtool_ops = {
 				     ETHTOOL_COALESCE_STATS_BLOCK_USECS |
 				     ETHTOOL_COALESCE_USE_ADAPTIVE_RX |
 				     ETHTOOL_COALESCE_USE_CQE,
+	.supported_ring_params	= ETHTOOL_RING_USE_TCP_DATA_SPLIT |
+				  ETHTOOL_RING_USE_HDS_THRS,
 	.get_link_ksettings	= bnxt_get_link_ksettings,
 	.set_link_ksettings	= bnxt_set_link_ksettings,
 	.get_fec_stats		= bnxt_get_fec_stats,
@@ -5372,6 +5436,8 @@ const struct ethtool_ops bnxt_ethtool_ops = {
 	.get_link_ext_stats	= bnxt_get_link_ext_stats,
 	.get_eee		= bnxt_get_eee,
 	.set_eee		= bnxt_set_eee,
+	.get_tunable		= bnxt_get_tunable,
+	.set_tunable		= bnxt_set_tunable,
 	.get_module_info	= bnxt_get_module_info,
 	.get_module_eeprom	= bnxt_get_module_eeprom,
 	.get_module_eeprom_by_page = bnxt_get_module_eeprom_by_page,
diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt_xdp.c b/drivers/net/ethernet/broadcom/bnxt/bnxt_xdp.c
index f88b641533fc..1bfff7f29310 100644
--- a/drivers/net/ethernet/broadcom/bnxt/bnxt_xdp.c
+++ b/drivers/net/ethernet/broadcom/bnxt/bnxt_xdp.c
@@ -395,6 +395,10 @@ static int bnxt_xdp_set(struct bnxt *bp, struct bpf_prog *prog)
 			    bp->dev->mtu, BNXT_MAX_PAGE_MODE_MTU);
 		return -EOPNOTSUPP;
 	}
+	if (prog && bp->flags & BNXT_FLAG_HDS) {
+		netdev_warn(dev, "XDP is disallowed when HDS is enabled.\n");
+		return -EOPNOTSUPP;
+	}
 	if (!(bp->flags & BNXT_FLAG_SHARED_RINGS)) {
 		netdev_warn(dev, "ethtool rx/tx channels must be combined to support XDP.\n");
 		return -EOPNOTSUPP;
diff --git a/drivers/net/netdevsim/ethtool.c b/drivers/net/netdevsim/ethtool.c
index 5fe1eaef99b5..9e0df40c71e1 100644
--- a/drivers/net/netdevsim/ethtool.c
+++ b/drivers/net/netdevsim/ethtool.c
@@ -2,7 +2,6 @@
 // Copyright (c) 2020 Facebook
 
 #include <linux/debugfs.h>
-#include <linux/ethtool.h>
 #include <linux/random.h>
 
 #include "netdevsim.h"
@@ -72,6 +71,12 @@ static void nsim_get_ringparam(struct net_device *dev,
 	struct netdevsim *ns = netdev_priv(dev);
 
 	memcpy(ring, &ns->ethtool.ring, sizeof(ns->ethtool.ring));
+	kernel_ring->tcp_data_split = dev->ethtool->hds_config;
+	kernel_ring->hds_thresh = dev->ethtool->hds_thresh;
+	kernel_ring->hds_thresh_max = NSIM_HDS_THRESHOLD_MAX;
+
+	if (kernel_ring->tcp_data_split == ETHTOOL_TCP_DATA_SPLIT_UNKNOWN)
+		kernel_ring->tcp_data_split = ETHTOOL_TCP_DATA_SPLIT_ENABLED;
 }
 
 static int nsim_set_ringparam(struct net_device *dev,
@@ -161,6 +166,8 @@ static int nsim_get_ts_info(struct net_device *dev,
 
 static const struct ethtool_ops nsim_ethtool_ops = {
 	.supported_coalesce_params	= ETHTOOL_COALESCE_ALL_PARAMS,
+	.supported_ring_params		= ETHTOOL_RING_USE_TCP_DATA_SPLIT |
+					  ETHTOOL_RING_USE_HDS_THRS,
 	.get_pause_stats	        = nsim_get_pause_stats,
 	.get_pauseparam		        = nsim_get_pauseparam,
 	.set_pauseparam		        = nsim_set_pauseparam,
@@ -182,6 +189,9 @@ static void nsim_ethtool_ring_init(struct netdevsim *ns)
 	ns->ethtool.ring.rx_jumbo_max_pending = 4096;
 	ns->ethtool.ring.rx_mini_max_pending = 4096;
 	ns->ethtool.ring.tx_max_pending = 4096;
+
+	ns->netdev->ethtool->hds_config = ETHTOOL_TCP_DATA_SPLIT_UNKNOWN;
+	ns->netdev->ethtool->hds_thresh = 0;
 }
 
 void nsim_ethtool_init(struct netdevsim *ns)
diff --git a/drivers/net/netdevsim/netdev.c b/drivers/net/netdevsim/netdev.c
index d013b6498539..f92b05ccdca9 100644
--- a/drivers/net/netdevsim/netdev.c
+++ b/drivers/net/netdevsim/netdev.c
@@ -15,6 +15,7 @@
 
 #include <linux/debugfs.h>
 #include <linux/etherdevice.h>
+#include <linux/ethtool_netlink.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/netdevice.h>
@@ -54,6 +55,7 @@ static int nsim_forward_skb(struct net_device *dev, struct sk_buff *skb,
 static netdev_tx_t nsim_start_xmit(struct sk_buff *skb, struct net_device *dev)
 {
 	struct netdevsim *ns = netdev_priv(dev);
+	struct ethtool_netdev_state *ethtool;
 	struct net_device *peer_dev;
 	unsigned int len = skb->len;
 	struct netdevsim *peer_ns;
@@ -74,6 +76,13 @@ static netdev_tx_t nsim_start_xmit(struct sk_buff *skb, struct net_device *dev)
 		rxq = rxq % peer_dev->num_rx_queues;
 	rq = peer_ns->rq[rxq];
 
+	ethtool = peer_dev->ethtool;
+	if (skb_is_nonlinear(skb) &&
+	    (ethtool->hds_config != ETHTOOL_TCP_DATA_SPLIT_ENABLED ||
+	     (ethtool->hds_config == ETHTOOL_TCP_DATA_SPLIT_ENABLED &&
+	      ethtool->hds_thresh > len)))
+		skb_linearize(skb);
+
 	skb_tx_timestamp(skb);
 	if (unlikely(nsim_forward_skb(peer_dev, skb, rq) == NET_RX_DROP))
 		goto out_drop_cnt;
diff --git a/drivers/net/netdevsim/netdevsim.h b/drivers/net/netdevsim/netdevsim.h
index a70f62af4c88..dcf073bc4802 100644
--- a/drivers/net/netdevsim/netdevsim.h
+++ b/drivers/net/netdevsim/netdevsim.h
@@ -16,6 +16,7 @@
 #include <linux/debugfs.h>
 #include <linux/device.h>
 #include <linux/ethtool.h>
+#include <linux/ethtool_netlink.h>
 #include <linux/kernel.h>
 #include <linux/list.h>
 #include <linux/netdevice.h>
@@ -36,6 +37,8 @@
 #define NSIM_IPSEC_VALID		BIT(31)
 #define NSIM_UDP_TUNNEL_N_PORTS		4
 
+#define NSIM_HDS_THRESHOLD_MAX		1024
+
 struct nsim_sa {
 	struct xfrm_state *xs;
 	__be32 ipaddr[4];
diff --git a/include/linux/ethtool.h b/include/linux/ethtool.h
index 20a86bd5f4e3..e4136b0df892 100644
--- a/include/linux/ethtool.h
+++ b/include/linux/ethtool.h
@@ -78,6 +78,9 @@ enum {
  * @cqe_size: Size of TX/RX completion queue event
  * @tx_push_buf_len: Size of TX push buffer
  * @tx_push_buf_max_len: Maximum allowed size of TX push buffer
+ * @hds_thresh: Packet size threshold for header data split (HDS)
+ * @hds_thresh_max: Maximum supported setting for @hds_threshold
+ *
  */
 struct kernel_ethtool_ringparam {
 	u32	rx_buf_len;
@@ -87,6 +90,8 @@ struct kernel_ethtool_ringparam {
 	u32	cqe_size;
 	u32	tx_push_buf_len;
 	u32	tx_push_buf_max_len;
+	u32	hds_thresh;
+	u32	hds_thresh_max;
 };
 
 /**
@@ -97,6 +102,7 @@ struct kernel_ethtool_ringparam {
  * @ETHTOOL_RING_USE_RX_PUSH: capture for setting rx_push
  * @ETHTOOL_RING_USE_TX_PUSH_BUF_LEN: capture for setting tx_push_buf_len
  * @ETHTOOL_RING_USE_TCP_DATA_SPLIT: capture for setting tcp_data_split
+ * @ETHTOOL_RING_USE_HDS_THRS: capture for setting header-data-split-thresh
  */
 enum ethtool_supported_ring_param {
 	ETHTOOL_RING_USE_RX_BUF_LEN		= BIT(0),
@@ -105,6 +111,7 @@ enum ethtool_supported_ring_param {
 	ETHTOOL_RING_USE_RX_PUSH		= BIT(3),
 	ETHTOOL_RING_USE_TX_PUSH_BUF_LEN	= BIT(4),
 	ETHTOOL_RING_USE_TCP_DATA_SPLIT		= BIT(5),
+	ETHTOOL_RING_USE_HDS_THRS		= BIT(6),
 };
 
 #define __ETH_RSS_HASH_BIT(bit)	((u32)1 << (bit))
@@ -1157,12 +1164,16 @@ int ethtool_virtdev_set_link_ksettings(struct net_device *dev,
  * @rss_ctx:		XArray of custom RSS contexts
  * @rss_lock:		Protects entries in @rss_ctx.  May be taken from
  *			within RTNL.
+ * @hds_thresh:		HDS Threshold value.
+ * @hds_config:		HDS value from userspace.
  * @wol_enabled:	Wake-on-LAN is enabled
  * @module_fw_flash_in_progress: Module firmware flashing is in progress.
  */
 struct ethtool_netdev_state {
 	struct xarray		rss_ctx;
 	struct mutex		rss_lock;
+	u32			hds_thresh;
+	u8			hds_config;
 	unsigned		wol_enabled:1;
 	unsigned		module_fw_flash_in_progress:1;
 };
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index bced03fb349e..3e6336775baf 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -4082,6 +4082,7 @@ struct sk_buff *dev_hard_start_xmit(struct sk_buff *skb, struct net_device *dev,
 int bpf_xdp_link_attach(const union bpf_attr *attr, struct bpf_prog *prog);
 u8 dev_xdp_prog_count(struct net_device *dev);
 int dev_xdp_propagate(struct net_device *dev, struct netdev_bpf *bpf);
+u8 dev_xdp_sb_prog_count(struct net_device *dev);
 u32 dev_xdp_prog_id(struct net_device *dev, enum bpf_xdp_mode mode);
 
 u32 dev_get_min_mp_channel_count(const struct net_device *dev);
diff --git a/include/uapi/linux/ethtool_netlink_generated.h b/include/uapi/linux/ethtool_netlink_generated.h
index 43993a2d68e5..2e17ff348f89 100644
--- a/include/uapi/linux/ethtool_netlink_generated.h
+++ b/include/uapi/linux/ethtool_netlink_generated.h
@@ -155,6 +155,8 @@ enum {
 	ETHTOOL_A_RINGS_RX_PUSH,
 	ETHTOOL_A_RINGS_TX_PUSH_BUF_LEN,
 	ETHTOOL_A_RINGS_TX_PUSH_BUF_LEN_MAX,
+	ETHTOOL_A_RINGS_HDS_THRESH,
+	ETHTOOL_A_RINGS_HDS_THRESH_MAX,
 
 	__ETHTOOL_A_RINGS_CNT,
 	ETHTOOL_A_RINGS_MAX = (__ETHTOOL_A_RINGS_CNT - 1)
diff --git a/net/core/dev.c b/net/core/dev.c
index fda4e1039bf0..47e6b0f73cfc 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -92,6 +92,7 @@
 #include <linux/netdevice.h>
 #include <linux/etherdevice.h>
 #include <linux/ethtool.h>
+#include <linux/ethtool_netlink.h>
 #include <linux/skbuff.h>
 #include <linux/kthread.h>
 #include <linux/bpf.h>
@@ -9550,11 +9551,31 @@ u8 dev_xdp_prog_count(struct net_device *dev)
 }
 EXPORT_SYMBOL_GPL(dev_xdp_prog_count);
 
+u8 dev_xdp_sb_prog_count(struct net_device *dev)
+{
+	u8 count = 0;
+	int i;
+
+	for (i = 0; i < __MAX_XDP_MODE; i++)
+		if (dev->xdp_state[i].prog &&
+		    !dev->xdp_state[i].prog->aux->xdp_has_frags)
+			count++;
+	return count;
+}
+
 int dev_xdp_propagate(struct net_device *dev, struct netdev_bpf *bpf)
 {
 	if (!dev->netdev_ops->ndo_bpf)
 		return -EOPNOTSUPP;
 
+	if (dev->ethtool->hds_config == ETHTOOL_TCP_DATA_SPLIT_ENABLED &&
+	    bpf->command == XDP_SETUP_PROG &&
+	    bpf->prog && !bpf->prog->aux->xdp_has_frags) {
+		NL_SET_ERR_MSG(bpf->extack,
+			       "unable to propagate XDP to device using tcp-data-split");
+		return -EBUSY;
+	}
+
 	if (dev_get_min_mp_channel_count(dev)) {
 		NL_SET_ERR_MSG(bpf->extack, "unable to propagate XDP to device using memory provider");
 		return -EBUSY;
@@ -9592,6 +9613,12 @@ static int dev_xdp_install(struct net_device *dev, enum bpf_xdp_mode mode,
 	struct netdev_bpf xdp;
 	int err;
 
+	if (dev->ethtool->hds_config == ETHTOOL_TCP_DATA_SPLIT_ENABLED &&
+	    prog && !prog->aux->xdp_has_frags) {
+		NL_SET_ERR_MSG(extack, "unable to install XDP to device using tcp-data-split");
+		return -EBUSY;
+	}
+
 	if (dev_get_min_mp_channel_count(dev)) {
 		NL_SET_ERR_MSG(extack, "unable to install XDP to device using memory provider");
 		return -EBUSY;
diff --git a/net/core/devmem.c b/net/core/devmem.c
index 0b6ed7525b22..c971b8aceac8 100644
--- a/net/core/devmem.c
+++ b/net/core/devmem.c
@@ -8,6 +8,7 @@
  */
 
 #include <linux/dma-buf.h>
+#include <linux/ethtool_netlink.h>
 #include <linux/genalloc.h>
 #include <linux/mm.h>
 #include <linux/netdevice.h>
@@ -140,6 +141,16 @@ int net_devmem_bind_dmabuf_to_queue(struct net_device *dev, u32 rxq_idx,
 		return -ERANGE;
 	}
 
+	if (dev->ethtool->hds_config != ETHTOOL_TCP_DATA_SPLIT_ENABLED) {
+		NL_SET_ERR_MSG(extack, "tcp-data-split is disabled");
+		return -EINVAL;
+	}
+
+	if (dev->ethtool->hds_thresh) {
+		NL_SET_ERR_MSG(extack, "hds-thresh is not zero");
+		return -EINVAL;
+	}
+
 	rxq = __netif_get_rx_queue(dev, rxq_idx);
 	if (rxq->mp_params.mp_priv) {
 		NL_SET_ERR_MSG(extack, "designated queue already memory provider bound");
diff --git a/net/ethtool/netlink.h b/net/ethtool/netlink.h
index 1ce0a3de1430..ff69ca0715de 100644
--- a/net/ethtool/netlink.h
+++ b/net/ethtool/netlink.h
@@ -456,7 +456,7 @@ extern const struct nla_policy ethnl_features_set_policy[ETHTOOL_A_FEATURES_WANT
 extern const struct nla_policy ethnl_privflags_get_policy[ETHTOOL_A_PRIVFLAGS_HEADER + 1];
 extern const struct nla_policy ethnl_privflags_set_policy[ETHTOOL_A_PRIVFLAGS_FLAGS + 1];
 extern const struct nla_policy ethnl_rings_get_policy[ETHTOOL_A_RINGS_HEADER + 1];
-extern const struct nla_policy ethnl_rings_set_policy[ETHTOOL_A_RINGS_TX_PUSH_BUF_LEN_MAX + 1];
+extern const struct nla_policy ethnl_rings_set_policy[ETHTOOL_A_RINGS_HDS_THRESH_MAX + 1];
 extern const struct nla_policy ethnl_channels_get_policy[ETHTOOL_A_CHANNELS_HEADER + 1];
 extern const struct nla_policy ethnl_channels_set_policy[ETHTOOL_A_CHANNELS_COMBINED_COUNT + 1];
 extern const struct nla_policy ethnl_coalesce_get_policy[ETHTOOL_A_COALESCE_HEADER + 1];
diff --git a/net/ethtool/rings.c b/net/ethtool/rings.c
index b7865a14fdf8..d8cd4e4d7762 100644
--- a/net/ethtool/rings.c
+++ b/net/ethtool/rings.c
@@ -61,7 +61,9 @@ static int rings_reply_size(const struct ethnl_req_info *req_base,
 	       nla_total_size(sizeof(u8))  +	/* _RINGS_TX_PUSH */
 	       nla_total_size(sizeof(u8))) +	/* _RINGS_RX_PUSH */
 	       nla_total_size(sizeof(u32)) +	/* _RINGS_TX_PUSH_BUF_LEN */
-	       nla_total_size(sizeof(u32));	/* _RINGS_TX_PUSH_BUF_LEN_MAX */
+	       nla_total_size(sizeof(u32)) +	/* _RINGS_TX_PUSH_BUF_LEN_MAX */
+	       nla_total_size(sizeof(u32)) +	/* _RINGS_HDS_THRESH */
+	       nla_total_size(sizeof(u32));	/* _RINGS_HDS_THRESH_MAX*/
 }
 
 static int rings_fill_reply(struct sk_buff *skb,
@@ -108,7 +110,12 @@ static int rings_fill_reply(struct sk_buff *skb,
 	     (nla_put_u32(skb, ETHTOOL_A_RINGS_TX_PUSH_BUF_LEN_MAX,
 			  kr->tx_push_buf_max_len) ||
 	      nla_put_u32(skb, ETHTOOL_A_RINGS_TX_PUSH_BUF_LEN,
-			  kr->tx_push_buf_len))))
+			  kr->tx_push_buf_len))) ||
+	    ((supported_ring_params & ETHTOOL_RING_USE_HDS_THRS) &&
+	     (nla_put_u32(skb, ETHTOOL_A_RINGS_HDS_THRESH,
+			  kr->hds_thresh) ||
+	      nla_put_u32(skb, ETHTOOL_A_RINGS_HDS_THRESH_MAX,
+			  kr->hds_thresh_max))))
 		return -EMSGSIZE;
 
 	return 0;
@@ -130,6 +137,7 @@ const struct nla_policy ethnl_rings_set_policy[] = {
 	[ETHTOOL_A_RINGS_TX_PUSH]		= NLA_POLICY_MAX(NLA_U8, 1),
 	[ETHTOOL_A_RINGS_RX_PUSH]		= NLA_POLICY_MAX(NLA_U8, 1),
 	[ETHTOOL_A_RINGS_TX_PUSH_BUF_LEN]	= { .type = NLA_U32 },
+	[ETHTOOL_A_RINGS_HDS_THRESH]		= { .type = NLA_U32 },
 };
 
 static int
@@ -155,6 +163,14 @@ ethnl_set_rings_validate(struct ethnl_req_info *req_info,
 		return -EOPNOTSUPP;
 	}
 
+	if (tb[ETHTOOL_A_RINGS_HDS_THRESH] &&
+	    !(ops->supported_ring_params & ETHTOOL_RING_USE_HDS_THRS)) {
+		NL_SET_ERR_MSG_ATTR(info->extack,
+				    tb[ETHTOOL_A_RINGS_HDS_THRESH],
+				    "setting hds-thresh is not supported");
+		return -EOPNOTSUPP;
+	}
+
 	if (tb[ETHTOOL_A_RINGS_CQE_SIZE] &&
 	    !(ops->supported_ring_params & ETHTOOL_RING_USE_CQE_SIZE)) {
 		NL_SET_ERR_MSG_ATTR(info->extack,
@@ -203,6 +219,7 @@ ethnl_set_rings(struct ethnl_req_info *req_info, struct genl_info *info)
 
 	dev->ethtool_ops->get_ringparam(dev, &ringparam,
 					&kernel_ringparam, info->extack);
+	kernel_ringparam.tcp_data_split = dev->ethtool->hds_config;
 
 	ethnl_update_u32(&ringparam.rx_pending, tb[ETHTOOL_A_RINGS_RX], &mod);
 	ethnl_update_u32(&ringparam.rx_mini_pending,
@@ -222,9 +239,32 @@ ethnl_set_rings(struct ethnl_req_info *req_info, struct genl_info *info)
 			tb[ETHTOOL_A_RINGS_RX_PUSH], &mod);
 	ethnl_update_u32(&kernel_ringparam.tx_push_buf_len,
 			 tb[ETHTOOL_A_RINGS_TX_PUSH_BUF_LEN], &mod);
+	ethnl_update_u32(&kernel_ringparam.hds_thresh,
+			 tb[ETHTOOL_A_RINGS_HDS_THRESH], &mod);
 	if (!mod)
 		return 0;
 
+	if (kernel_ringparam.tcp_data_split == ETHTOOL_TCP_DATA_SPLIT_ENABLED &&
+	    dev_xdp_sb_prog_count(dev)) {
+		NL_SET_ERR_MSG_ATTR(info->extack,
+				    tb[ETHTOOL_A_RINGS_TCP_DATA_SPLIT],
+				    "tcp-data-split can not be enabled with single buffer XDP");
+		return -EINVAL;
+	}
+
+	if (dev_get_min_mp_channel_count(dev)) {
+		if (kernel_ringparam.tcp_data_split !=
+		    ETHTOOL_TCP_DATA_SPLIT_ENABLED) {
+			NL_SET_ERR_MSG(info->extack,
+				       "can't disable tcp-data-split while device has memory provider enabled");
+			return -EINVAL;
+		} else if (kernel_ringparam.hds_thresh) {
+			NL_SET_ERR_MSG(info->extack,
+				       "can't set non-zero hds_thresh while device is memory provider enabled");
+			return -EINVAL;
+		}
+	}
+
 	/* ensure new ring parameters are within limits */
 	if (ringparam.rx_pending > ringparam.rx_max_pending)
 		err_attr = tb[ETHTOOL_A_RINGS_RX];
@@ -234,6 +274,8 @@ ethnl_set_rings(struct ethnl_req_info *req_info, struct genl_info *info)
 		err_attr = tb[ETHTOOL_A_RINGS_RX_JUMBO];
 	else if (ringparam.tx_pending > ringparam.tx_max_pending)
 		err_attr = tb[ETHTOOL_A_RINGS_TX];
+	else if (kernel_ringparam.hds_thresh > kernel_ringparam.hds_thresh_max)
+		err_attr = tb[ETHTOOL_A_RINGS_HDS_THRESH];
 	else
 		err_attr = NULL;
 	if (err_attr) {
@@ -252,6 +294,11 @@ ethnl_set_rings(struct ethnl_req_info *req_info, struct genl_info *info)
 
 	ret = dev->ethtool_ops->set_ringparam(dev, &ringparam,
 					      &kernel_ringparam, info->extack);
+	if (!ret) {
+		dev->ethtool->hds_config = kernel_ringparam.tcp_data_split;
+		dev->ethtool->hds_thresh = kernel_ringparam.hds_thresh;
+	}
+
 	return ret < 0 ? ret : 1;
 }
 
diff --git a/tools/testing/selftests/drivers/net/Makefile b/tools/testing/selftests/drivers/net/Makefile
index 469179c18935..137470bdee0c 100644
--- a/tools/testing/selftests/drivers/net/Makefile
+++ b/tools/testing/selftests/drivers/net/Makefile
@@ -12,6 +12,7 @@ TEST_PROGS := \
 	queues.py \
 	stats.py \
 	shaper.py \
+	hds.py \
 # end of TEST_PROGS
 
 include ../../lib.mk
diff --git a/tools/testing/selftests/drivers/net/hds.py b/tools/testing/selftests/drivers/net/hds.py
new file mode 100755
index 000000000000..394971b25c0b
--- /dev/null
+++ b/tools/testing/selftests/drivers/net/hds.py
@@ -0,0 +1,120 @@
+#!/usr/bin/env python3
+# SPDX-License-Identifier: GPL-2.0
+
+import errno
+from lib.py import ksft_run, ksft_exit, ksft_eq, ksft_raises, KsftSkipEx
+from lib.py import EthtoolFamily, NlError
+from lib.py import NetDrvEnv
+
+def get_hds(cfg, netnl) -> None:
+    try:
+        rings = netnl.rings_get({'header': {'dev-index': cfg.ifindex}})
+    except NlError as e:
+        raise KsftSkipEx('ring-get not supported by device')
+    if 'tcp-data-split' not in rings:
+        raise KsftSkipEx('tcp-data-split not supported by device')
+
+def get_hds_thresh(cfg, netnl) -> None:
+    try:
+        rings = netnl.rings_get({'header': {'dev-index': cfg.ifindex}})
+    except NlError as e:
+        raise KsftSkipEx('ring-get not supported by device')
+    if 'hds-thresh' not in rings:
+        raise KsftSkipEx('hds-thresh not supported by device')
+
+def set_hds_enable(cfg, netnl) -> None:
+    try:
+        netnl.rings_set({'header': {'dev-index': cfg.ifindex}, 'tcp-data-split': 'enabled'})
+    except NlError as e:
+        if e.error == errno.EINVAL:
+            raise KsftSkipEx("disabling of HDS not supported by the device")
+        elif e.error == errno.EOPNOTSUPP:
+            raise KsftSkipEx("ring-set not supported by the device")
+    try:
+        rings = netnl.rings_get({'header': {'dev-index': cfg.ifindex}})
+    except NlError as e:
+        raise KsftSkipEx('ring-get not supported by device')
+    if 'tcp-data-split' not in rings:
+        raise KsftSkipEx('tcp-data-split not supported by device')
+
+    ksft_eq('enabled', rings['tcp-data-split'])
+
+def set_hds_disable(cfg, netnl) -> None:
+    try:
+        netnl.rings_set({'header': {'dev-index': cfg.ifindex}, 'tcp-data-split': 'disabled'})
+    except NlError as e:
+        if e.error == errno.EINVAL:
+            raise KsftSkipEx("disabling of HDS not supported by the device")
+        elif e.error == errno.EOPNOTSUPP:
+            raise KsftSkipEx("ring-set not supported by the device")
+    try:
+        rings = netnl.rings_get({'header': {'dev-index': cfg.ifindex}})
+    except NlError as e:
+        raise KsftSkipEx('ring-get not supported by device')
+    if 'tcp-data-split' not in rings:
+        raise KsftSkipEx('tcp-data-split not supported by device')
+
+    ksft_eq('disabled', rings['tcp-data-split'])
+
+def set_hds_thresh_zero(cfg, netnl) -> None:
+    try:
+        netnl.rings_set({'header': {'dev-index': cfg.ifindex}, 'hds-thresh': 0})
+    except NlError as e:
+        if e.error == errno.EINVAL:
+            raise KsftSkipEx("hds-thresh-set not supported by the device")
+        elif e.error == errno.EOPNOTSUPP:
+            raise KsftSkipEx("ring-set not supported by the device")
+    try:
+        rings = netnl.rings_get({'header': {'dev-index': cfg.ifindex}})
+    except NlError as e:
+        raise KsftSkipEx('ring-get not supported by device')
+    if 'hds-thresh' not in rings:
+        raise KsftSkipEx('hds-thresh not supported by device')
+
+    ksft_eq(0, rings['hds-thresh'])
+
+def set_hds_thresh_max(cfg, netnl) -> None:
+    try:
+        rings = netnl.rings_get({'header': {'dev-index': cfg.ifindex}})
+    except NlError as e:
+        raise KsftSkipEx('ring-get not supported by device')
+    if 'hds-thresh' not in rings:
+        raise KsftSkipEx('hds-thresh not supported by device')
+    try:
+        netnl.rings_set({'header': {'dev-index': cfg.ifindex}, 'hds-thresh': rings['hds-thresh-max']})
+    except NlError as e:
+        if e.error == errno.EINVAL:
+            raise KsftSkipEx("hds-thresh-set not supported by the device")
+        elif e.error == errno.EOPNOTSUPP:
+            raise KsftSkipEx("ring-set not supported by the device")
+    rings = netnl.rings_get({'header': {'dev-index': cfg.ifindex}})
+    ksft_eq(rings['hds-thresh'], rings['hds-thresh-max'])
+
+def set_hds_thresh_gt(cfg, netnl) -> None:
+    try:
+        rings = netnl.rings_get({'header': {'dev-index': cfg.ifindex}})
+    except NlError as e:
+        raise KsftSkipEx('ring-get not supported by device')
+    if 'hds-thresh' not in rings:
+        raise KsftSkipEx('hds-thresh not supported by device')
+    if 'hds-thresh-max' not in rings:
+        raise KsftSkipEx('hds-thresh-max not defined by device')
+    hds_gt = rings['hds-thresh-max'] + 1
+    with ksft_raises(NlError) as e:
+        netnl.rings_set({'header': {'dev-index': cfg.ifindex}, 'hds-thresh': hds_gt})
+    ksft_eq(e.exception.nl_msg.error, -errno.EINVAL)
+
+def main() -> None:
+    with NetDrvEnv(__file__, queue_count=3) as cfg:
+        ksft_run([get_hds,
+                  get_hds_thresh,
+                  set_hds_disable,
+                  set_hds_enable,
+                  set_hds_thresh_zero,
+                  set_hds_thresh_max,
+                  set_hds_thresh_gt],
+                 args=(cfg, EthtoolFamily()))
+    ksft_exit()
+
+if __name__ == "__main__":
+    main()