[PATCH net-next 0/4] bnxt_en: add XDP RSS hash metadata support

[PATCH net-next 0/4] bnxt_en: add XDP RSS hash metadata support

[Chris J Arges]

This series adds XDP RSS hash metadata extraction support for the bnxt_en
driver and includes selftests to validate the functionality. I was able
to test this on a BCM57414 NIC.

The driver changes introduce a bnxt_xdp_buff wrapper that carries
hardware RX completion descriptors alongside the xdp_buff, then use it
to implement bpf_xdp_metadata_rx_hash().

The selftest changes refactor common XDP/BPF helpers into a shared
library and add a new xdp_metadata test that verifies RSS hash
extraction for TCP and UDP traffic via device-bound XDP programs.

Chris J Arges (4):
  bnxt_en: use bnxt_xdp_buff for xdp context
  bnxt_en: Implement XDP RSS hash metadata extraction
  selftests: net: move common xdp.py functions into lib
  selftests: drv-net: xdp: Add rss_hash metadata tests

 drivers/net/ethernet/broadcom/bnxt/bnxt.c     |  30 ++--
 drivers/net/ethernet/broadcom/bnxt/bnxt.h     |   2 +
 drivers/net/ethernet/broadcom/bnxt/bnxt_xdp.c |  47 +++++
 drivers/net/ethernet/broadcom/bnxt/bnxt_xdp.h |  10 ++
 tools/testing/selftests/drivers/net/Makefile  |   1 +
 .../selftests/drivers/net/lib/py/__init__.py  |   2 +
 tools/testing/selftests/drivers/net/xdp.py    |  95 +++-------
 .../selftests/drivers/net/xdp_metadata.py     | 144 ++++++++++++++++
 .../testing/selftests/net/lib/py/__init__.py  |   2 +
 tools/testing/selftests/net/lib/py/bpf.py     |  68 ++++++++
 .../selftests/net/lib/xdp_metadata.bpf.c      | 163 ++++++++++++++++++
 11 files changed, 482 insertions(+), 82 deletions(-)
 create mode 100644 tools/testing/selftests/drivers/net/xdp_metadata.py
 create mode 100644 tools/testing/selftests/net/lib/py/bpf.py
 create mode 100644 tools/testing/selftests/net/lib/xdp_metadata.bpf.c


base-commit: 7dff99b354601dd01829e1511711846e04340a69
-- 
2.43.0

[PATCH net-next 1/4] bnxt_en: use bnxt_xdp_buff for xdp context

[Chris J Arges]

This adds bnxt_xdp_buff which embeds the xdp_buff struct and stores
pointers to hardware RX completion descriptors (rx_cmp and rx_cmp_ext)
along with the completion type.

Signed-off-by: Chris J Arges <carges@cloudflare.com>
---
 drivers/net/ethernet/broadcom/bnxt/bnxt.c     | 25 +++++++++++--------
 drivers/net/ethernet/broadcom/bnxt/bnxt_xdp.h |  7 ++++++
 2 files changed, 22 insertions(+), 10 deletions(-)

diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt.c b/drivers/net/ethernet/broadcom/bnxt/bnxt.c
index e062d5d400da..a80ec5391b89 100644
--- a/drivers/net/ethernet/broadcom/bnxt/bnxt.c
+++ b/drivers/net/ethernet/broadcom/bnxt/bnxt.c
@@ -2118,7 +2118,7 @@ static int bnxt_rx_pkt(struct bnxt *bp, struct bnxt_cp_ring_info *cpr,
 	bool xdp_active = false;
 	dma_addr_t dma_addr;
 	struct sk_buff *skb;
-	struct xdp_buff xdp;
+	struct bnxt_xdp_buff bnxt_xdp;
 	u32 flags, misc;
 	u32 cmpl_ts;
 	void *data;
@@ -2231,9 +2231,13 @@ static int bnxt_rx_pkt(struct bnxt *bp, struct bnxt_cp_ring_info *cpr,
 	dma_addr = rx_buf->mapping;
 
 	if (bnxt_xdp_attached(bp, rxr)) {
-		bnxt_xdp_buff_init(bp, rxr, cons, data_ptr, len, &xdp);
+		bnxt_xdp.rxcmp = rxcmp;
+		bnxt_xdp.rxcmp1 = rxcmp1;
+		bnxt_xdp.cmp_type = cmp_type;
+
+		bnxt_xdp_buff_init(bp, rxr, cons, data_ptr, len, &bnxt_xdp.xdp);
 		if (agg_bufs) {
-			u32 frag_len = bnxt_rx_agg_netmems_xdp(bp, cpr, &xdp,
+			u32 frag_len = bnxt_rx_agg_netmems_xdp(bp, cpr, &bnxt_xdp.xdp,
 							       cp_cons,
 							       agg_bufs,
 							       false);
@@ -2245,12 +2249,12 @@ static int bnxt_rx_pkt(struct bnxt *bp, struct bnxt_cp_ring_info *cpr,
 	}
 
 	if (xdp_active) {
-		if (bnxt_rx_xdp(bp, rxr, cons, &xdp, data, &data_ptr, &len, event)) {
+		if (bnxt_rx_xdp(bp, rxr, cons, &bnxt_xdp.xdp, data, &data_ptr, &len, event)) {
 			rc = 1;
 			goto next_rx;
 		}
-		if (xdp_buff_has_frags(&xdp)) {
-			sinfo = xdp_get_shared_info_from_buff(&xdp);
+		if (xdp_buff_has_frags(&bnxt_xdp.xdp)) {
+			sinfo = xdp_get_shared_info_from_buff(&bnxt_xdp.xdp);
 			agg_bufs = sinfo->nr_frags;
 		} else {
 			agg_bufs = 0;
@@ -2261,7 +2265,7 @@ static int bnxt_rx_pkt(struct bnxt *bp, struct bnxt_cp_ring_info *cpr,
 		if (!xdp_active)
 			skb = bnxt_copy_skb(bnapi, data_ptr, len, dma_addr);
 		else
-			skb = bnxt_copy_xdp(bnapi, &xdp, len, dma_addr);
+			skb = bnxt_copy_xdp(bnapi, &bnxt_xdp.xdp, len, dma_addr);
 		bnxt_reuse_rx_data(rxr, cons, data);
 		if (!skb) {
 			if (agg_bufs) {
@@ -2269,7 +2273,7 @@ static int bnxt_rx_pkt(struct bnxt *bp, struct bnxt_cp_ring_info *cpr,
 					bnxt_reuse_rx_agg_bufs(cpr, cp_cons, 0,
 							       agg_bufs, false);
 				else
-					bnxt_xdp_buff_frags_free(rxr, &xdp);
+					bnxt_xdp_buff_frags_free(rxr, &bnxt_xdp.xdp);
 			}
 			goto oom_next_rx;
 		}
@@ -2293,10 +2297,11 @@ static int bnxt_rx_pkt(struct bnxt *bp, struct bnxt_cp_ring_info *cpr,
 			if (!skb)
 				goto oom_next_rx;
 		} else {
-			skb = bnxt_xdp_build_skb(bp, skb, agg_bufs, rxr, &xdp);
+			skb = bnxt_xdp_build_skb(bp, skb, agg_bufs,
+						 rxr, &bnxt_xdp.xdp);
 			if (!skb) {
 				/* we should be able to free the old skb here */
-				bnxt_xdp_buff_frags_free(rxr, &xdp);
+				bnxt_xdp_buff_frags_free(rxr, &bnxt_xdp.xdp);
 				goto oom_next_rx;
 			}
 		}
diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt_xdp.h b/drivers/net/ethernet/broadcom/bnxt/bnxt_xdp.h
index 8933a0dec09a..8c66698bde11 100644
--- a/drivers/net/ethernet/broadcom/bnxt/bnxt_xdp.h
+++ b/drivers/net/ethernet/broadcom/bnxt/bnxt_xdp.h
@@ -12,6 +12,13 @@
 
 DECLARE_STATIC_KEY_FALSE(bnxt_xdp_locking_key);
 
+struct bnxt_xdp_buff {
+	struct xdp_buff xdp;
+	struct rx_cmp *rxcmp;
+	struct rx_cmp_ext *rxcmp1;
+	u8 cmp_type;
+};
+
 struct bnxt_sw_tx_bd *bnxt_xmit_bd(struct bnxt *bp,
 				   struct bnxt_tx_ring_info *txr,
 				   dma_addr_t mapping, u32 len,
-- 
2.43.0

[PATCH net-next 2/4] bnxt_en: Implement XDP RSS hash metadata extraction

[Chris J Arges]

Add support for extracting RSS hash values and hash types from hardware
completion descriptors in XDP programs for bnxt_en.

Add IP_TYPE definition for determining if completion is ipv4 or ipv6. In
addition add ITYPE_ICMP flag for identifying ICMP completions.

Signed-off-by: Chris J Arges <carges@cloudflare.com>
---
 drivers/net/ethernet/broadcom/bnxt/bnxt.c     |  5 ++
 drivers/net/ethernet/broadcom/bnxt/bnxt.h     |  2 +
 drivers/net/ethernet/broadcom/bnxt/bnxt_xdp.c | 47 +++++++++++++++++++
 drivers/net/ethernet/broadcom/bnxt/bnxt_xdp.h |  3 ++
 4 files changed, 57 insertions(+)

diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt.c b/drivers/net/ethernet/broadcom/bnxt/bnxt.c
index a80ec5391b89..a8ea73c880e9 100644
--- a/drivers/net/ethernet/broadcom/bnxt/bnxt.c
+++ b/drivers/net/ethernet/broadcom/bnxt/bnxt.c
@@ -15905,6 +15905,10 @@ static const struct net_device_ops bnxt_netdev_ops = {
 	.ndo_hwtstamp_set	= bnxt_hwtstamp_set,
 };
 
+static const struct xdp_metadata_ops bnxt_xdp_metadata_ops = {
+	.xmo_rx_hash		= bnxt_xdp_rx_hash,
+};
+
 static void bnxt_get_queue_stats_rx(struct net_device *dev, int i,
 				    struct netdev_queue_stats_rx *stats)
 {
@@ -16789,6 +16793,7 @@ static int bnxt_init_one(struct pci_dev *pdev, const struct pci_device_id *ent)
 		goto init_err_free;
 
 	dev->netdev_ops = &bnxt_netdev_ops;
+	dev->xdp_metadata_ops = &bnxt_xdp_metadata_ops;
 	dev->stat_ops = &bnxt_stat_ops;
 	dev->watchdog_timeo = BNXT_TX_TIMEOUT;
 	dev->ethtool_ops = &bnxt_ethtool_ops;
diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt.h b/drivers/net/ethernet/broadcom/bnxt/bnxt.h
index 9a41b9e0423c..13eb1ca814b7 100644
--- a/drivers/net/ethernet/broadcom/bnxt/bnxt.h
+++ b/drivers/net/ethernet/broadcom/bnxt/bnxt.h
@@ -232,6 +232,7 @@ struct rx_cmp {
 	 #define RX_CMP_FLAGS_ITYPE_UDP				 (3 << 12)
 	 #define RX_CMP_FLAGS_ITYPE_FCOE			 (4 << 12)
 	 #define RX_CMP_FLAGS_ITYPE_ROCE			 (5 << 12)
+	 #define RX_CMP_FLAGS_ITYPE_ICMP			 (7 << 12)
 	 #define RX_CMP_FLAGS_ITYPE_PTP_WO_TS			 (8 << 12)
 	 #define RX_CMP_FLAGS_ITYPE_PTP_W_TS			 (9 << 12)
 	#define RX_CMP_LEN					(0xffff << 16)
@@ -311,6 +312,7 @@ struct rx_cmp_ext {
 	#define RX_CMP_FLAGS2_T_IP_CS_CALC			(0x1 << 2)
 	#define RX_CMP_FLAGS2_T_L4_CS_CALC			(0x1 << 3)
 	#define RX_CMP_FLAGS2_META_FORMAT_VLAN			(0x1 << 4)
+	#define RX_CMP_FLAGS2_IP_TYPE				(0x1 << 8)
 	__le32 rx_cmp_meta_data;
 	#define RX_CMP_FLAGS2_METADATA_TCI_MASK			0xffff
 	#define RX_CMP_FLAGS2_METADATA_VID_MASK			0xfff
diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt_xdp.c b/drivers/net/ethernet/broadcom/bnxt/bnxt_xdp.c
index 85cbeb35681c..f75060374163 100644
--- a/drivers/net/ethernet/broadcom/bnxt/bnxt_xdp.c
+++ b/drivers/net/ethernet/broadcom/bnxt/bnxt_xdp.c
@@ -472,3 +472,50 @@ bnxt_xdp_build_skb(struct bnxt *bp, struct sk_buff *skb, u8 num_frags,
 				  xdp_buff_get_skb_flags(xdp));
 	return skb;
 }
+
+int bnxt_xdp_rx_hash(const struct xdp_md *ctx, u32 *hash,
+		     enum xdp_rss_hash_type *rss_type)
+{
+	const struct bnxt_xdp_buff *xdp = (void *)ctx;
+	const struct rx_cmp *rxcmp = xdp->rxcmp;
+	const struct rx_cmp_ext *rxcmp1 = xdp->rxcmp1;
+	u32 itypes;
+	enum xdp_rss_hash_type hash_type = 0;
+
+	if (!rxcmp || !RX_CMP_HASH_VALID(rxcmp))
+		return -ENODATA;
+
+	*hash = le32_to_cpu(rxcmp->rx_cmp_rss_hash);
+
+	if (!rxcmp1) {
+		*rss_type = XDP_RSS_TYPE_L2;
+		return 0;
+	}
+
+	if (xdp->cmp_type == CMP_TYPE_RX_L2_CMP) {
+		itypes = RX_CMP_ITYPES(rxcmp);
+		if (rxcmp1->rx_cmp_flags2 &
+		    cpu_to_le32(RX_CMP_FLAGS2_IP_TYPE)) {
+			hash_type |= XDP_RSS_TYPE_L3_IPV6;
+		} else {
+			hash_type |= XDP_RSS_TYPE_L3_IPV4;
+		}
+
+		switch (itypes) {
+		case RX_CMP_FLAGS_ITYPE_TCP:
+			hash_type |= XDP_RSS_L4 | XDP_RSS_L4_TCP;
+			break;
+		case RX_CMP_FLAGS_ITYPE_UDP:
+			hash_type |= XDP_RSS_L4 | XDP_RSS_L4_UDP;
+			break;
+		case RX_CMP_FLAGS_ITYPE_ICMP:
+			hash_type |= XDP_RSS_L4 | XDP_RSS_L4_ICMP;
+			break;
+		default:
+			break;
+		}
+	}
+
+	*rss_type = hash_type;
+	return 0;
+}
diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt_xdp.h b/drivers/net/ethernet/broadcom/bnxt/bnxt_xdp.h
index 8c66698bde11..fb4f9143929f 100644
--- a/drivers/net/ethernet/broadcom/bnxt/bnxt_xdp.h
+++ b/drivers/net/ethernet/broadcom/bnxt/bnxt_xdp.h
@@ -41,4 +41,7 @@ void bnxt_xdp_buff_frags_free(struct bnxt_rx_ring_info *rxr,
 struct sk_buff *bnxt_xdp_build_skb(struct bnxt *bp, struct sk_buff *skb,
 				   u8 num_frags, struct bnxt_rx_ring_info *rxr,
 				   struct xdp_buff *xdp);
+int bnxt_xdp_rx_hash(const struct xdp_md *ctx, u32 *hash,
+		     enum xdp_rss_hash_type *rss_type);
+
 #endif
-- 
2.43.0

Re: [PATCH net-next 2/4] bnxt_en: Implement XDP RSS hash metadata extraction

[Joe Damato]

On Fri, Feb 27, 2026 at 11:40:18AM -0600, Chris J Arges wrote:
> Add support for extracting RSS hash values and hash types from hardware
> completion descriptors in XDP programs for bnxt_en.
> 
> Add IP_TYPE definition for determining if completion is ipv4 or ipv6. In
> addition add ITYPE_ICMP flag for identifying ICMP completions.
>
> Signed-off-by: Chris J Arges <carges@cloudflare.com>
> ---
>  drivers/net/ethernet/broadcom/bnxt/bnxt.c     |  5 ++
>  drivers/net/ethernet/broadcom/bnxt/bnxt.h     |  2 +
>  drivers/net/ethernet/broadcom/bnxt/bnxt_xdp.c | 47 +++++++++++++++++++
>  drivers/net/ethernet/broadcom/bnxt/bnxt_xdp.h |  3 ++
>  4 files changed, 57 insertions(+)
 
[...]

> diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt_xdp.c b/drivers/net/ethernet/broadcom/bnxt/bnxt_xdp.c
> index 85cbeb35681c..f75060374163 100644
> --- a/drivers/net/ethernet/broadcom/bnxt/bnxt_xdp.c
> +++ b/drivers/net/ethernet/broadcom/bnxt/bnxt_xdp.c
> @@ -472,3 +472,50 @@ bnxt_xdp_build_skb(struct bnxt *bp, struct sk_buff *skb, u8 num_frags,
>  				  xdp_buff_get_skb_flags(xdp));
>  	return skb;
>  }
> +
> +int bnxt_xdp_rx_hash(const struct xdp_md *ctx, u32 *hash,
> +		     enum xdp_rss_hash_type *rss_type)
> +{
> +	const struct bnxt_xdp_buff *xdp = (void *)ctx;
> +	const struct rx_cmp *rxcmp = xdp->rxcmp;
> +	const struct rx_cmp_ext *rxcmp1 = xdp->rxcmp1;
> +	u32 itypes;
> +	enum xdp_rss_hash_type hash_type = 0;

Nit: This may need to be put into RCT style. (?)

Everything else seemed OK to me...

Reviewed-by: Joe Damato <joe@dama.to>

[PATCH net-next 3/4] selftests: net: move common xdp.py functions into lib

[Chris J Arges]

This moves a few functions which can be useful to other python programs
that manipulate XDP programs. This also refactors xdp.py to use the
refactored functions.

Signed-off-by: Chris J Arges <carges@cloudflare.com>
---
 .../selftests/drivers/net/lib/py/__init__.py  |  2 +
 tools/testing/selftests/drivers/net/xdp.py    | 95 +++++--------------
 .../testing/selftests/net/lib/py/__init__.py  |  2 +
 tools/testing/selftests/net/lib/py/bpf.py     | 68 +++++++++++++
 4 files changed, 95 insertions(+), 72 deletions(-)
 create mode 100644 tools/testing/selftests/net/lib/py/bpf.py

diff --git a/tools/testing/selftests/drivers/net/lib/py/__init__.py b/tools/testing/selftests/drivers/net/lib/py/__init__.py
index 8b75faa9af6d..29c4913cd434 100644
--- a/tools/testing/selftests/drivers/net/lib/py/__init__.py
+++ b/tools/testing/selftests/drivers/net/lib/py/__init__.py
@@ -23,6 +23,7 @@ try:
     from net.lib.py import CmdExitFailure
     from net.lib.py import bkg, cmd, bpftool, bpftrace, defer, ethtool, \
         fd_read_timeout, ip, rand_port, wait_port_listen, wait_file
+    from net.lib.py import bpf_map_set, bpf_map_dump, bpf_prog_map_ids
     from net.lib.py import KsftSkipEx, KsftFailEx, KsftXfailEx
     from net.lib.py import ksft_disruptive, ksft_exit, ksft_pr, ksft_run, \
         ksft_setup, ksft_variants, KsftNamedVariant
@@ -36,6 +37,7 @@ try:
                "bkg", "cmd", "bpftool", "bpftrace", "defer", "ethtool",
                "fd_read_timeout", "ip", "rand_port",
                "wait_port_listen", "wait_file",
+               "bpf_map_set", "bpf_map_dump", "bpf_prog_map_ids",
                "KsftSkipEx", "KsftFailEx", "KsftXfailEx",
                "ksft_disruptive", "ksft_exit", "ksft_pr", "ksft_run",
                "ksft_setup", "ksft_variants", "KsftNamedVariant",
diff --git a/tools/testing/selftests/drivers/net/xdp.py b/tools/testing/selftests/drivers/net/xdp.py
index e54df158dfe9..10d821156db1 100755
--- a/tools/testing/selftests/drivers/net/xdp.py
+++ b/tools/testing/selftests/drivers/net/xdp.py
@@ -16,7 +16,8 @@ from lib.py import KsftNamedVariant, ksft_variants
 from lib.py import KsftFailEx, NetDrvEpEnv
 from lib.py import EthtoolFamily, NetdevFamily, NlError
 from lib.py import bkg, cmd, rand_port, wait_port_listen
-from lib.py import ip, bpftool, defer
+from lib.py import ip, defer
+from lib.py import bpf_map_set, bpf_map_dump, bpf_prog_map_ids
 
 
 class TestConfig(Enum):
@@ -122,47 +123,11 @@ def _load_xdp_prog(cfg, bpf_info):
     xdp_info = ip(f"-d link show dev {cfg.ifname}", json=True)[0]
     prog_info["id"] = xdp_info["xdp"]["prog"]["id"]
     prog_info["name"] = xdp_info["xdp"]["prog"]["name"]
-    prog_id = prog_info["id"]
-
-    map_ids = bpftool(f"prog show id {prog_id}", json=True)["map_ids"]
-    prog_info["maps"] = {}
-    for map_id in map_ids:
-        name = bpftool(f"map show id {map_id}", json=True)["name"]
-        prog_info["maps"][name] = map_id
+    prog_info["maps"] = bpf_prog_map_ids(prog_info["id"])
 
     return prog_info
 
 
-def format_hex_bytes(value):
-    """
-    Helper function that converts an integer into a formatted hexadecimal byte string.
-
-    Args:
-        value: An integer representing the number to be converted.
-
-    Returns:
-        A string representing hexadecimal equivalent of value, with bytes separated by spaces.
-    """
-    hex_str = value.to_bytes(4, byteorder='little', signed=True)
-    return ' '.join(f'{byte:02x}' for byte in hex_str)
-
-
-def _set_xdp_map(map_name, key, value):
-    """
-    Updates an XDP map with a given key-value pair using bpftool.
-
-    Args:
-        map_name: The name of the XDP map to update.
-        key: The key to update in the map, formatted as a hexadecimal string.
-        value: The value to associate with the key, formatted as a hexadecimal string.
-    """
-    key_formatted = format_hex_bytes(key)
-    value_formatted = format_hex_bytes(value)
-    bpftool(
-        f"map update name {map_name} key hex {key_formatted} value hex {value_formatted}"
-    )
-
-
 def _get_stats(xdp_map_id):
     """
     Retrieves and formats statistics from an XDP map.
@@ -177,25 +142,11 @@ def _get_stats(xdp_map_id):
     Raises:
         KsftFailEx: If the stats retrieval fails.
     """
-    stats_dump = bpftool(f"map dump id {xdp_map_id}", json=True)
-    if not stats_dump:
+    stats = bpf_map_dump(xdp_map_id)
+    if not stats:
         raise KsftFailEx(f"Failed to get stats for map {xdp_map_id}")
 
-    stats_formatted = {}
-    for key in range(0, 5):
-        val = stats_dump[key]["formatted"]["value"]
-        if stats_dump[key]["formatted"]["key"] == XDPStats.RX.value:
-            stats_formatted[XDPStats.RX.value] = val
-        elif stats_dump[key]["formatted"]["key"] == XDPStats.PASS.value:
-            stats_formatted[XDPStats.PASS.value] = val
-        elif stats_dump[key]["formatted"]["key"] == XDPStats.DROP.value:
-            stats_formatted[XDPStats.DROP.value] = val
-        elif stats_dump[key]["formatted"]["key"] == XDPStats.TX.value:
-            stats_formatted[XDPStats.TX.value] = val
-        elif stats_dump[key]["formatted"]["key"] == XDPStats.ABORT.value:
-            stats_formatted[XDPStats.ABORT.value] = val
-
-    return stats_formatted
+    return stats
 
 
 def _test_pass(cfg, bpf_info, msg_sz):
@@ -211,8 +162,8 @@ def _test_pass(cfg, bpf_info, msg_sz):
     prog_info = _load_xdp_prog(cfg, bpf_info)
     port = rand_port()
 
-    _set_xdp_map("map_xdp_setup", TestConfig.MODE.value, XDPAction.PASS.value)
-    _set_xdp_map("map_xdp_setup", TestConfig.PORT.value, port)
+    bpf_map_set("map_xdp_setup", TestConfig.MODE.value, XDPAction.PASS.value)
+    bpf_map_set("map_xdp_setup", TestConfig.PORT.value, port)
 
     ksft_eq(_test_udp(cfg, port, msg_sz), True, "UDP packet exchange failed")
     stats = _get_stats(prog_info["maps"]["map_xdp_stats"])
@@ -258,8 +209,8 @@ def _test_drop(cfg, bpf_info, msg_sz):
     prog_info = _load_xdp_prog(cfg, bpf_info)
     port = rand_port()
 
-    _set_xdp_map("map_xdp_setup", TestConfig.MODE.value, XDPAction.DROP.value)
-    _set_xdp_map("map_xdp_setup", TestConfig.PORT.value, port)
+    bpf_map_set("map_xdp_setup", TestConfig.MODE.value, XDPAction.DROP.value)
+    bpf_map_set("map_xdp_setup", TestConfig.PORT.value, port)
 
     ksft_eq(_test_udp(cfg, port, msg_sz), False, "UDP packet exchange should fail")
     stats = _get_stats(prog_info["maps"]["map_xdp_stats"])
@@ -305,8 +256,8 @@ def _test_xdp_native_tx(cfg, bpf_info, payload_lens):
     prog_info = _load_xdp_prog(cfg, bpf_info)
     port = rand_port()
 
-    _set_xdp_map("map_xdp_setup", TestConfig.MODE.value, XDPAction.TX.value)
-    _set_xdp_map("map_xdp_setup", TestConfig.PORT.value, port)
+    bpf_map_set("map_xdp_setup", TestConfig.MODE.value, XDPAction.TX.value)
+    bpf_map_set("map_xdp_setup", TestConfig.PORT.value, port)
 
     expected_pkts = 0
     for payload_len in payload_lens:
@@ -454,15 +405,15 @@ def _test_xdp_native_tail_adjst(cfg, pkt_sz_lst, offset_lst):
     prog_info = _load_xdp_prog(cfg, bpf_info)
 
     # Configure the XDP map for tail adjustment
-    _set_xdp_map("map_xdp_setup", TestConfig.MODE.value, XDPAction.TAIL_ADJST.value)
-    _set_xdp_map("map_xdp_setup", TestConfig.PORT.value, port)
+    bpf_map_set("map_xdp_setup", TestConfig.MODE.value, XDPAction.TAIL_ADJST.value)
+    bpf_map_set("map_xdp_setup", TestConfig.PORT.value, port)
 
     for offset in offset_lst:
         tag = format(random.randint(65, 90), "02x")
 
-        _set_xdp_map("map_xdp_setup", TestConfig.ADJST_OFFSET.value, offset)
+        bpf_map_set("map_xdp_setup", TestConfig.ADJST_OFFSET.value, offset)
         if offset > 0:
-            _set_xdp_map("map_xdp_setup", TestConfig.ADJST_TAG.value, int(tag, 16))
+            bpf_map_set("map_xdp_setup", TestConfig.ADJST_TAG.value, int(tag, 16))
 
         for pkt_sz in pkt_sz_lst:
             test_str = "".join(random.choice(string.ascii_lowercase) for _ in range(pkt_sz))
@@ -574,8 +525,8 @@ def _test_xdp_native_head_adjst(cfg, prog, pkt_sz_lst, offset_lst):
     prog_info = _load_xdp_prog(cfg, BPFProgInfo(prog, "xdp_native.bpf.o", "xdp.frags", 9000))
     port = rand_port()
 
-    _set_xdp_map("map_xdp_setup", TestConfig.MODE.value, XDPAction.HEAD_ADJST.value)
-    _set_xdp_map("map_xdp_setup", TestConfig.PORT.value, port)
+    bpf_map_set("map_xdp_setup", TestConfig.MODE.value, XDPAction.HEAD_ADJST.value)
+    bpf_map_set("map_xdp_setup", TestConfig.PORT.value, port)
 
     hds_thresh = get_hds_thresh(cfg)
     for offset in offset_lst:
@@ -595,11 +546,11 @@ def _test_xdp_native_head_adjst(cfg, prog, pkt_sz_lst, offset_lst):
             test_str = ''.join(random.choice(string.ascii_lowercase) for _ in range(pkt_sz))
             tag = format(random.randint(65, 90), '02x')
 
-            _set_xdp_map("map_xdp_setup",
+            bpf_map_set("map_xdp_setup",
                      TestConfig.ADJST_OFFSET.value,
                      offset)
-            _set_xdp_map("map_xdp_setup", TestConfig.ADJST_TAG.value, int(tag, 16))
-            _set_xdp_map("map_xdp_setup", TestConfig.ADJST_OFFSET.value, offset)
+            bpf_map_set("map_xdp_setup", TestConfig.ADJST_TAG.value, int(tag, 16))
+            bpf_map_set("map_xdp_setup", TestConfig.ADJST_OFFSET.value, offset)
 
             recvd_str = _exchg_udp(cfg, port, test_str)
 
@@ -691,8 +642,8 @@ def test_xdp_native_qstats(cfg, act):
     prog_info = _load_xdp_prog(cfg, bpf_info)
     port = rand_port()
 
-    _set_xdp_map("map_xdp_setup", TestConfig.MODE.value, act.value)
-    _set_xdp_map("map_xdp_setup", TestConfig.PORT.value, port)
+    bpf_map_set("map_xdp_setup", TestConfig.MODE.value, act.value)
+    bpf_map_set("map_xdp_setup", TestConfig.PORT.value, port)
 
     # Discard the input, but we need a listener to avoid ICMP errors
     rx_udp = f"socat -{cfg.addr_ipver} -T 2 -u UDP-RECV:{port},reuseport " + \
diff --git a/tools/testing/selftests/net/lib/py/__init__.py b/tools/testing/selftests/net/lib/py/__init__.py
index f528b67639de..c1aa9d0f8dcf 100644
--- a/tools/testing/selftests/net/lib/py/__init__.py
+++ b/tools/testing/selftests/net/lib/py/__init__.py
@@ -14,6 +14,7 @@ from .netns import NetNS, NetNSEnter
 from .nsim import NetdevSim, NetdevSimDev
 from .utils import CmdExitFailure, fd_read_timeout, cmd, bkg, defer, \
     bpftool, ip, ethtool, bpftrace, rand_port, wait_port_listen, wait_file, tool
+from .bpf import bpf_map_set, bpf_map_dump, bpf_prog_map_ids
 from .ynl import NlError, YnlFamily, EthtoolFamily, NetdevFamily, RtnlFamily, RtnlAddrFamily
 from .ynl import NetshaperFamily, DevlinkFamily, PSPFamily
 
@@ -27,6 +28,7 @@ __all__ = ["KSRC",
            "CmdExitFailure", "fd_read_timeout", "cmd", "bkg", "defer",
            "bpftool", "ip", "ethtool", "bpftrace", "rand_port",
            "wait_port_listen", "wait_file", "tool",
+           "bpf_map_set", "bpf_map_dump", "bpf_prog_map_ids",
            "NetdevSim", "NetdevSimDev",
            "NetshaperFamily", "DevlinkFamily", "PSPFamily", "NlError",
            "YnlFamily", "EthtoolFamily", "NetdevFamily", "RtnlFamily",
diff --git a/tools/testing/selftests/net/lib/py/bpf.py b/tools/testing/selftests/net/lib/py/bpf.py
new file mode 100644
index 000000000000..96b29d41c34b
--- /dev/null
+++ b/tools/testing/selftests/net/lib/py/bpf.py
@@ -0,0 +1,68 @@
+# SPDX-License-Identifier: GPL-2.0
+
+"""
+BPF helper utilities for kernel selftests.
+
+Provides common operations for interacting with BPF maps and programs
+via bpftool, used by XDP and other BPF-based test files.
+"""
+
+from .utils import bpftool
+
+def format_hex_bytes(value):
+    """
+    Helper function that converts an integer into a formatted hexadecimal byte string.
+
+    Args:
+        value: An integer representing the number to be converted.
+
+    Returns:
+        A string representing hexadecimal equivalent of value, with bytes separated by spaces.
+    """
+    hex_str = value.to_bytes(4, byteorder='little', signed=True)
+    return ' '.join(f'{byte:02x}' for byte in hex_str)
+
+
+def bpf_map_set(map_name, key, value):
+    """
+    Updates an XDP map with a given key-value pair using bpftool.
+
+    Args:
+        map_name: The name of the XDP map to update.
+        key: The key to update in the map, formatted as a hexadecimal string.
+        value: The value to associate with the key, formatted as a hexadecimal string.
+    """
+    key_formatted = format_hex_bytes(key)
+    value_formatted = format_hex_bytes(value)
+    bpftool(
+        f"map update name {map_name} key hex {key_formatted} value hex {value_formatted}"
+    )
+
+def bpf_map_dump(map_id):
+    """Dump all entries of a BPF array map.
+
+    Args:
+        map_id: Numeric map ID (as returned by bpftool prog show).
+
+    Returns:
+        A dict mapping formatted key (int) to formatted value (int).
+    """
+    raw = bpftool(f"map dump id {map_id}", json=True)
+    return {e["formatted"]["key"]: e["formatted"]["value"] for e in raw}
+
+
+def bpf_prog_map_ids(prog_id):
+    """Get the map name-to-ID mapping for a loaded BPF program.
+
+    Args:
+        prog_id: Numeric program ID.
+
+    Returns:
+        A dict mapping map name (str) to map ID (int).
+    """
+    map_ids = bpftool(f"prog show id {prog_id}", json=True)["map_ids"]
+    maps = {}
+    for mid in map_ids:
+        name = bpftool(f"map show id {mid}", json=True)["name"]
+        maps[name] = mid
+    return maps
-- 
2.43.0

Re: [PATCH net-next 3/4] selftests: net: move common xdp.py functions into lib

[Joe Damato]

On Fri, Feb 27, 2026 at 11:40:19AM -0600, Chris J Arges wrote:
> This moves a few functions which can be useful to other python programs
> that manipulate XDP programs. This also refactors xdp.py to use the
> refactored functions.
> 
> Signed-off-by: Chris J Arges <carges@cloudflare.com>
> ---
>  .../selftests/drivers/net/lib/py/__init__.py  |  2 +
>  tools/testing/selftests/drivers/net/xdp.py    | 95 +++++--------------
>  .../testing/selftests/net/lib/py/__init__.py  |  2 +
>  tools/testing/selftests/net/lib/py/bpf.py     | 68 +++++++++++++
>  4 files changed, 95 insertions(+), 72 deletions(-)
>  create mode 100644 tools/testing/selftests/net/lib/py/bpf.py

Reviewed-by: Joe Damato <joe@dama.to>

[PATCH net-next 4/4] selftests: drv-net: xdp: Add rss_hash metadata tests

[Chris J Arges]

This test loads xdp_metadata.bpf which calls bpf_xdp_metadata_rx_hash() on
incoming packets. The metadata from that packet is then sent to a BPF
map for validation. It borrows structure from xdp.py, reusing common
functions.

The test checks the device's xdp-rx-metadata-features via netlink
before running and skips on devices that do not advertise hash support.
This allows the tests to pass, but one can override the device and test on
HW or veth devices.

The test is fairly simple and just verifies that a TCP or UDP packet can be
identified as an L4 flow. This minimal test also passes if run on a veth
device.

Signed-off-by: Chris J Arges <carges@cloudflare.com>
---
 tools/testing/selftests/drivers/net/Makefile  |   1 +
 .../selftests/drivers/net/xdp_metadata.py     | 144 ++++++++++++++++
 .../selftests/net/lib/xdp_metadata.bpf.c      | 163 ++++++++++++++++++
 3 files changed, 308 insertions(+)
 create mode 100644 tools/testing/selftests/drivers/net/xdp_metadata.py
 create mode 100644 tools/testing/selftests/net/lib/xdp_metadata.bpf.c

diff --git a/tools/testing/selftests/drivers/net/Makefile b/tools/testing/selftests/drivers/net/Makefile
index 8154d6d429d3..6f9708e8d05a 100644
--- a/tools/testing/selftests/drivers/net/Makefile
+++ b/tools/testing/selftests/drivers/net/Makefile
@@ -23,6 +23,7 @@ TEST_PROGS := \
 	shaper.py \
 	stats.py \
 	xdp.py \
+	xdp_metadata.py \
 # end of TEST_PROGS
 
 # YNL files, must be before "include ..lib.mk"
diff --git a/tools/testing/selftests/drivers/net/xdp_metadata.py b/tools/testing/selftests/drivers/net/xdp_metadata.py
new file mode 100644
index 000000000000..7b8a3d00b0ac
--- /dev/null
+++ b/tools/testing/selftests/drivers/net/xdp_metadata.py
@@ -0,0 +1,144 @@
+#!/usr/bin/env python3
+# SPDX-License-Identifier: GPL-2.0
+
+"""
+Tests for XDP metadata kfuncs (e.g. bpf_xdp_metadata_rx_hash).
+
+These tests load device-bound XDP programs from xdp_metadata.bpf.o
+that call metadata kfuncs, send traffic, and verify the extracted
+metadata via BPF maps.
+"""
+from lib.py import ksft_run, ksft_exit, ksft_ge, ksft_ne, ksft_pr
+from lib.py import KsftNamedVariant, ksft_variants
+from lib.py import CmdExitFailure, KsftSkipEx, NetDrvEpEnv
+from lib.py import NetdevFamily
+from lib.py import bkg, cmd, rand_port, wait_port_listen
+from lib.py import ip, bpftool, defer
+from lib.py import bpf_map_set, bpf_map_dump, bpf_prog_map_ids
+
+
+def _load_xdp_metadata_prog(cfg, prog_name, bpf_file="xdp_metadata.bpf.o"):
+    """Load a device-bound XDP metadata program and return prog/map info.
+
+    Returns:
+        dict with 'id', 'name', and 'maps' (name -> map_id).
+    """
+    abs_path = cfg.net_lib_dir / bpf_file
+    pin_dir = "/sys/fs/bpf/xdp_metadata_test"
+
+    cmd(f"rm -rf {pin_dir}", shell=True, fail=False)
+    cmd(f"mkdir -p {pin_dir}", shell=True)
+
+    try:
+        bpftool(f"prog loadall {abs_path} {pin_dir} type xdp "
+                f"xdpmeta_dev {cfg.ifname}")
+    except CmdExitFailure as e:
+        cmd(f"rm -rf {pin_dir}", shell=True, fail=False)
+        raise KsftSkipEx(
+            f"Failed to load device-bound XDP program '{prog_name}'"
+        ) from e
+    defer(cmd, f"rm -rf {pin_dir}", shell=True, fail=False)
+
+    pin_path = f"{pin_dir}/{prog_name}"
+    ip(f"link set dev {cfg.ifname} xdpdrv pinned {pin_path}")
+    defer(ip, f"link set dev {cfg.ifname} xdpdrv off")
+
+    xdp_info = ip(f"-d link show dev {cfg.ifname}", json=True)[0]
+    prog_id = xdp_info["xdp"]["prog"]["id"]
+
+    return {"id": prog_id,
+            "name": xdp_info["xdp"]["prog"]["name"],
+            "maps": bpf_prog_map_ids(prog_id)}
+
+
+def _send_probe(cfg, port, proto="tcp"):
+    """Send a single payload from the remote end using socat.
+
+    Args:
+        cfg: Configuration object containing network settings.
+        port: Port number for the exchange.
+        proto: Protocol to use, either "tcp" or "udp".
+    """
+    cfg.require_cmd("socat", remote=True)
+
+    if proto == "tcp":
+        rx_cmd = f"socat -{cfg.addr_ipver} -T 2 TCP-LISTEN:{port},reuseport STDOUT"
+        tx_cmd = f"echo -n rss_hash_test | socat -t 2 -u STDIN TCP:{cfg.baddr}:{port}"
+    else:
+        rx_cmd = f"socat -{cfg.addr_ipver} -T 2 -u UDP-RECV:{port},reuseport STDOUT"
+        tx_cmd = f"echo -n rss_hash_test | socat -t 2 -u STDIN UDP:{cfg.baddr}:{port}"
+
+    with bkg(rx_cmd, exit_wait=True):
+        wait_port_listen(port, proto=proto)
+        cmd(tx_cmd, host=cfg.remote, shell=True)
+
+
+# BPF map keys matching the enums in xdp_metadata.bpf.c
+_SETUP_KEY_PORT = 1
+
+_RSS_KEY_HASH = 0
+_RSS_KEY_TYPE = 1
+_RSS_KEY_PKT_CNT = 2
+_RSS_KEY_ERR_CNT = 3
+
+
+@ksft_variants([
+    KsftNamedVariant("tcp", "tcp"),
+    KsftNamedVariant("udp", "udp"),
+])
+def test_xdp_rss_hash(cfg, proto):
+    """Test RSS hash metadata extraction via bpf_xdp_metadata_rx_hash().
+
+    This test will only run on devices that support xdp-rx-metadata-features.
+
+    Loads the xdp_rss_hash program from xdp_metadata, sends a packet using
+    the specified protocol, and verifies that the program extracted a non-zero
+    hash with an L4 hash type.
+    """
+    dev_info = cfg.netnl.dev_get({"ifindex": cfg.ifindex})
+    rx_meta = dev_info.get("xdp-rx-metadata-features", [])
+    if "hash" not in rx_meta:
+        raise KsftSkipEx("device does not support XDP rx hash metadata")
+
+    prog_info = _load_xdp_metadata_prog(cfg, "xdp_rss_hash")
+
+    port = rand_port()
+    bpf_map_set("map_xdp_setup", _SETUP_KEY_PORT, port)
+
+    rss_map_id = prog_info["maps"]["map_rss"]
+
+    _send_probe(cfg, port, proto=proto)
+
+    rss = bpf_map_dump(rss_map_id)
+
+    pkt_cnt = rss.get(_RSS_KEY_PKT_CNT, 0)
+    err_cnt = rss.get(_RSS_KEY_ERR_CNT, 0)
+    hash_val = rss.get(_RSS_KEY_HASH, 0)
+    hash_type = rss.get(_RSS_KEY_TYPE, 0)
+
+    ksft_ge(pkt_cnt, 1, "should have received at least one packet")
+    ksft_pr(f"  RSS hash error count: {err_cnt}")
+
+    ksft_ne(hash_val, 0,
+            f"RSS hash should be non-zero for {proto.upper()} traffic")
+    ksft_pr(f"  RSS hash: {hash_val:#010x}")
+
+    ksft_pr(f"  RSS hash type: {hash_type:#06x}")
+    XDP_RSS_L4 = 0x8  # BIT(3) from enum xdp_rss_hash_type
+    ksft_ne(hash_type & XDP_RSS_L4, 0,
+            f"RSS hash type should include L4 for {proto.upper()} traffic")
+
+
+def main():
+    with NetDrvEpEnv(__file__) as cfg:
+        cfg.netnl = NetdevFamily()
+        ksft_run(
+            [
+                test_xdp_rss_hash,
+            ],
+            args=(cfg,))
+    ksft_exit()
+
+
+if __name__ == "__main__":
+    main()
diff --git a/tools/testing/selftests/net/lib/xdp_metadata.bpf.c b/tools/testing/selftests/net/lib/xdp_metadata.bpf.c
new file mode 100644
index 000000000000..f71f59215239
--- /dev/null
+++ b/tools/testing/selftests/net/lib/xdp_metadata.bpf.c
@@ -0,0 +1,163 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <stddef.h>
+#include <linux/bpf.h>
+#include <linux/in.h>
+#include <linux/if_ether.h>
+#include <linux/ip.h>
+#include <linux/ipv6.h>
+#include <linux/udp.h>
+#include <linux/tcp.h>
+#include <bpf/bpf_endian.h>
+#include <bpf/bpf_helpers.h>
+
+enum {
+	XDP_PORT = 1,
+	XDP_PROTO = 4,
+} xdp_map_setup_keys;
+
+struct {
+	__uint(type, BPF_MAP_TYPE_ARRAY);
+	__uint(max_entries, 5);
+	__type(key, __u32);
+	__type(value, __s32);
+} map_xdp_setup SEC(".maps");
+
+/* RSS hash results: key 0 = hash, key 1 = hash type,
+ * key 2 = packet count, key 3 = error count.
+ */
+enum {
+	RSS_KEY_HASH = 0,
+	RSS_KEY_TYPE = 1,
+	RSS_KEY_PKT_CNT = 2,
+	RSS_KEY_ERR_CNT = 3,
+};
+
+struct {
+	__uint(type, BPF_MAP_TYPE_ARRAY);
+	__type(key, __u32);
+	__type(value, __u32);
+	__uint(max_entries, 4);
+} map_rss SEC(".maps");
+
+/* Mirror of enum xdp_rss_hash_type from include/net/xdp.h.
+ * Needed because the enum is not part of UAPI headers.
+ */
+enum xdp_rss_hash_type {
+	XDP_RSS_L3_IPV4 = 1U << 0,
+	XDP_RSS_L3_IPV6 = 1U << 1,
+	XDP_RSS_L3_DYNHDR = 1U << 2,
+	XDP_RSS_L4 = 1U << 3,
+	XDP_RSS_L4_TCP = 1U << 4,
+	XDP_RSS_L4_UDP = 1U << 5,
+	XDP_RSS_L4_SCTP = 1U << 6,
+	XDP_RSS_L4_IPSEC = 1U << 7,
+	XDP_RSS_L4_ICMP = 1U << 8,
+};
+
+extern int bpf_xdp_metadata_rx_hash(const struct xdp_md *ctx, __u32 *hash,
+				    enum xdp_rss_hash_type *rss_type) __ksym;
+
+static __always_inline __u16 get_dest_port(void *l4, void *data_end,
+					   __u8 protocol)
+{
+	if (protocol == IPPROTO_UDP) {
+		struct udphdr *udp = l4;
+
+		if ((void *)(udp + 1) > data_end)
+			return 0;
+		return udp->dest;
+	} else if (protocol == IPPROTO_TCP) {
+		struct tcphdr *tcp = l4;
+
+		if ((void *)(tcp + 1) > data_end)
+			return 0;
+		return tcp->dest;
+	}
+
+	return 0;
+}
+
+SEC("xdp")
+int xdp_rss_hash(struct xdp_md *ctx)
+{
+	void *data_end = (void *)(long)ctx->data_end;
+	void *data = (void *)(long)ctx->data;
+	enum xdp_rss_hash_type rss_type = 0;
+	struct ethhdr *eth = data;
+	__u8 l4_proto = 0;
+	__u32 hash = 0;
+	__u32 key, val;
+	void *l4 = NULL;
+	__u32 *cnt;
+	int ret;
+
+	if ((void *)(eth + 1) > data_end)
+		return XDP_PASS;
+
+	if (eth->h_proto == bpf_htons(ETH_P_IP)) {
+		struct iphdr *iph = (void *)(eth + 1);
+
+		if ((void *)(iph + 1) > data_end)
+			return XDP_PASS;
+		l4_proto = iph->protocol;
+		l4 = (void *)(iph + 1);
+	} else if (eth->h_proto == bpf_htons(ETH_P_IPV6)) {
+		struct ipv6hdr *ip6h = (void *)(eth + 1);
+
+		if ((void *)(ip6h + 1) > data_end)
+			return XDP_PASS;
+		l4_proto = ip6h->nexthdr;
+		l4 = (void *)(ip6h + 1);
+	}
+
+	if (!l4)
+		return XDP_PASS;
+
+	/* Filter on the configured protocol (map_xdp_setup key XDP_PROTO).
+	 * When set, only process packets matching the requested L4 protocol.
+	 */
+	key = XDP_PROTO;
+	__s32 *proto_cfg = bpf_map_lookup_elem(&map_xdp_setup, &key);
+
+	if (proto_cfg && *proto_cfg != 0 && l4_proto != (__u8)*proto_cfg)
+		return XDP_PASS;
+
+	/* Filter on the configured port (map_xdp_setup key XDP_PORT).
+	 * Only applies to protocols with ports (UDP, TCP).
+	 */
+	key = XDP_PORT;
+	__s32 *port_cfg = bpf_map_lookup_elem(&map_xdp_setup, &key);
+
+	if (port_cfg && *port_cfg != 0) {
+		__u16 dest = get_dest_port(l4, data_end, l4_proto);
+
+		if (!dest || bpf_ntohs(dest) != (__u16)*port_cfg)
+			return XDP_PASS;
+	}
+
+	ret = bpf_xdp_metadata_rx_hash(ctx, &hash, &rss_type);
+	if (ret < 0) {
+		key = RSS_KEY_ERR_CNT;
+		cnt = bpf_map_lookup_elem(&map_rss, &key);
+		if (cnt)
+			__sync_fetch_and_add(cnt, 1);
+		return XDP_PASS;
+	}
+
+	key = RSS_KEY_HASH;
+	bpf_map_update_elem(&map_rss, &key, &hash, BPF_ANY);
+
+	key = RSS_KEY_TYPE;
+	val = (__u32)rss_type;
+	bpf_map_update_elem(&map_rss, &key, &val, BPF_ANY);
+
+	key = RSS_KEY_PKT_CNT;
+	cnt = bpf_map_lookup_elem(&map_rss, &key);
+	if (cnt)
+		__sync_fetch_and_add(cnt, 1);
+
+	return XDP_PASS;
+}
+
+char _license[] SEC("license") = "GPL";
-- 
2.43.0

Re: [PATCH net-next 4/4] selftests: drv-net: xdp: Add rss_hash metadata tests

[Jakub Kicinski]

On Fri, 27 Feb 2026 11:40:20 -0600 Chris J Arges wrote:
> This test loads xdp_metadata.bpf which calls bpf_xdp_metadata_rx_hash() on
> incoming packets. The metadata from that packet is then sent to a BPF
> map for validation. It borrows structure from xdp.py, reusing common
> functions.
> 
> The test checks the device's xdp-rx-metadata-features via netlink
> before running and skips on devices that do not advertise hash support.
> This allows the tests to pass, but one can override the device and test on
> HW or veth devices.
> 
> The test is fairly simple and just verifies that a TCP or UDP packet can be
> identified as an L4 flow. This minimal test also passes if run on a veth
> device.

Thanks for adding the test! The series doesn't seem to apply, I think
you'll need to rebase on latest net-next and repost.

> diff --git a/tools/testing/selftests/drivers/net/Makefile b/tools/testing/selftests/drivers/net/Makefile
> index 8154d6d429d3..6f9708e8d05a 100644
> --- a/tools/testing/selftests/drivers/net/Makefile
> +++ b/tools/testing/selftests/drivers/net/Makefile

the drivers/net tests are expected to run against netdevsim.
You'll need to implement the xmo in netdevsim.. Or does it
already support them given it uses xdp_generic under the hood?
Alternatively you can move the test under hw/ and not bother.


> +# BPF map keys matching the enums in xdp_metadata.bpf.c
> +_SETUP_KEY_PORT = 1
> +
> +_RSS_KEY_HASH = 0
> +_RSS_KEY_TYPE = 1
> +_RSS_KEY_PKT_CNT = 2
> +_RSS_KEY_ERR_CNT = 3

Does pylint complain about those ? We try to keep pylint --disable=R
clean for new tests.


> +    ksft_ge(pkt_cnt, 1, "should have received at least one packet")
> +    ksft_pr(f"  RSS hash error count: {err_cnt}")

Does it randomly report non-zero?
I'm wondering why not ksft_eq(err_cnt, 0, comment='RSS hash error count')

> +    ksft_ne(hash_val, 0,
> +            f"RSS hash should be non-zero for {proto.upper()} traffic")
> +    ksft_pr(f"  RSS hash: {hash_val:#010x}")
> +
> +    ksft_pr(f"  RSS hash type: {hash_type:#06x}")
> +    XDP_RSS_L4 = 0x8  # BIT(3) from enum xdp_rss_hash_type
> +    ksft_ne(hash_type & XDP_RSS_L4, 0,
> +            f"RSS hash type should include L4 for {proto.upper()} traffic")
> +
> +
> +def main():

add:

	""" Ksft boiler plate main """

to silence pylint?