Merge branch 'eth-fbnic-fix-and-improve-header-data-split-configuration'

Bobby Eshleman says:

====================
eth: fbnic: fix and improve header/data split configuration

This series fixes TCP HDS configuration in the fbnic driver and adds a
devmem selftest for the intended behavior.

The issues fixed include setting the correct CSR for EN_HDR_SPLIT,
adjusting the hds threshold clamp to avoid long headers overflowing into
the payload page, and configuring the device to use L4/L3/L2 header
boundaries when present by programming the DMA hint bit unconditionally
for all steering rule types.

Prior to these fixes, small payloads fail devmem.check_rx_hds().

Testing:

IFC0=enp1s0
IFC1=eth0

export REMOTE_TYPE=netns
export REMOTE_ARGS=ns-remote
export NETIF=$IFC0
export LOCAL_V4=192.0.3.1
export REMOTE_V4=192.0.3.2
sysctl -w net.ipv6.conf.$IFC0.keep_addr_on_down=1

./tools/testing/selftests/drivers/net/hw/devmem.py

TAP version 13
1..4
ok 1 devmem.check_rx
ok 2 devmem.check_tx
ok 3 devmem.check_tx_chunks
ok 4 devmem.check_rx_hds

To: Alexander Duyck <alexanderduyck@fb.com>
To: Jakub Kicinski <kuba@kernel.org>
To: kernel-team@meta.com
To: Andrew Lunn <andrew+netdev@lunn.ch>
To: David S. Miller <davem@davemloft.net>
To: Eric Dumazet <edumazet@google.com>
To: Paolo Abeni <pabeni@redhat.com>
To: Mohsin Bashir <mohsin.bashr@gmail.com>
To: Shuah Khan <shuah@kernel.org>
Cc: netdev@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: linux-kselftest@vger.kernel.org

Signed-off-by: Bobby Eshleman <bobbyeshleman@meta.com>
====================

Link: https://patch.msgid.link/20260211-fbnic-tcp-hds-fixes-v1-0-55d050e6f606@meta.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

6 files changed, 48 insertions, 17 deletions

diff --git a/drivers/net/ethernet/meta/fbnic/fbnic_ethtool.c b/drivers/net/ethernet/meta/fbnic/fbnic_ethtool.c
index 11745a2d8a44..401c2196b9ff 100644
--- a/drivers/net/ethernet/meta/fbnic/fbnic_ethtool.c
+++ b/drivers/net/ethernet/meta/fbnic/fbnic_ethtool.c
@@ -1145,6 +1145,9 @@ ipv6_flow:
 		return -EINVAL;
 	}
 
+	dest |= FIELD_PREP(FBNIC_RPC_ACT_TBL0_DMA_HINT,
+			   FBNIC_RCD_HDR_AL_DMA_HINT_L4);
+
 	/* Write action table values */
 	act_tcam->dest = dest;
 	act_tcam->rss_en_mask = fbnic_flow_hash_2_rss_en_mask(fbn, hash_idx);
diff --git a/drivers/net/ethernet/meta/fbnic/fbnic_rpc.c b/drivers/net/ethernet/meta/fbnic/fbnic_rpc.c
index 7f31e890031c..42a186db43ea 100644
--- a/drivers/net/ethernet/meta/fbnic/fbnic_rpc.c
+++ b/drivers/net/ethernet/meta/fbnic/fbnic_rpc.c
@@ -338,9 +338,8 @@ void fbnic_rss_reinit(struct fbnic_dev *fbd, struct fbnic_net *fbn)
 		else if (tstamp_mask & (1u << flow_type))
 			dest |= FBNIC_RPC_ACT_TBL0_TS_ENA;
 
-		if (act1_value[flow_type] & FBNIC_RPC_TCAM_ACT1_L4_VALID)
-			dest |= FIELD_PREP(FBNIC_RPC_ACT_TBL0_DMA_HINT,
-					   FBNIC_RCD_HDR_AL_DMA_HINT_L4);
+		dest |= FIELD_PREP(FBNIC_RPC_ACT_TBL0_DMA_HINT,
+				   FBNIC_RCD_HDR_AL_DMA_HINT_L4);
 
 		rss_en_mask = fbnic_flow_hash_2_rss_en_mask(fbn, flow_type);
 
diff --git a/drivers/net/ethernet/meta/fbnic/fbnic_txrx.c b/drivers/net/ethernet/meta/fbnic/fbnic_txrx.c
index e29959241ff3..4aaa928bf8ab 100644
--- a/drivers/net/ethernet/meta/fbnic/fbnic_txrx.c
+++ b/drivers/net/ethernet/meta/fbnic/fbnic_txrx.c
@@ -2591,7 +2591,8 @@ write_ctl:
 }
 
 static void fbnic_config_drop_mode_rcq(struct fbnic_napi_vector *nv,
-				       struct fbnic_ring *rcq, bool tx_pause)
+				       struct fbnic_ring *rcq, bool tx_pause,
+				       bool hdr_split)
 {
 	struct fbnic_net *fbn = netdev_priv(nv->napi.dev);
 	u32 drop_mode, rcq_ctl;
@@ -2604,22 +2605,26 @@ static void fbnic_config_drop_mode_rcq(struct fbnic_napi_vector *nv,
 	/* Specify packet layout */
 	rcq_ctl = FIELD_PREP(FBNIC_QUEUE_RDE_CTL0_DROP_MODE_MASK, drop_mode) |
 	    FIELD_PREP(FBNIC_QUEUE_RDE_CTL0_MIN_HROOM_MASK, FBNIC_RX_HROOM) |
-	    FIELD_PREP(FBNIC_QUEUE_RDE_CTL0_MIN_TROOM_MASK, FBNIC_RX_TROOM);
+	    FIELD_PREP(FBNIC_QUEUE_RDE_CTL0_MIN_TROOM_MASK, FBNIC_RX_TROOM) |
+	    FIELD_PREP(FBNIC_QUEUE_RDE_CTL0_EN_HDR_SPLIT, hdr_split);
 
 	fbnic_ring_wr32(rcq, FBNIC_QUEUE_RDE_CTL0, rcq_ctl);
 }
 
-void fbnic_config_drop_mode(struct fbnic_net *fbn, bool tx_pause)
+void fbnic_config_drop_mode(struct fbnic_net *fbn, bool txp)
 {
+	bool hds;
 	int i, t;
 
+	hds = fbn->hds_thresh < FBNIC_HDR_BYTES_MIN;
+
 	for (i = 0; i < fbn->num_napi; i++) {
 		struct fbnic_napi_vector *nv = fbn->napi[i];
 
 		for (t = 0; t < nv->rxt_count; t++) {
 			struct fbnic_q_triad *qt = &nv->qt[nv->txt_count + t];
 
-			fbnic_config_drop_mode_rcq(nv, &qt->cmpl, tx_pause);
+			fbnic_config_drop_mode_rcq(nv, &qt->cmpl, txp, hds);
 		}
 	}
 }
@@ -2670,20 +2675,18 @@ static void fbnic_enable_rcq(struct fbnic_napi_vector *nv,
 {
 	struct fbnic_net *fbn = netdev_priv(nv->napi.dev);
 	u32 log_size = fls(rcq->size_mask);
-	u32 hds_thresh = fbn->hds_thresh;
 	u32 rcq_ctl = 0;
-
-	fbnic_config_drop_mode_rcq(nv, rcq, fbn->tx_pause);
+	bool hdr_split;
+	u32 hds_thresh;
 
 	/* Force lower bound on MAX_HEADER_BYTES. Below this, all frames should
 	 * be split at L4. It would also result in the frames being split at
 	 * L2/L3 depending on the frame size.
 	 */
-	if (fbn->hds_thresh < FBNIC_HDR_BYTES_MIN) {
-		rcq_ctl = FBNIC_QUEUE_RDE_CTL0_EN_HDR_SPLIT;
-		hds_thresh = FBNIC_HDR_BYTES_MIN;
-	}
+	hdr_split = fbn->hds_thresh < FBNIC_HDR_BYTES_MIN;
+	fbnic_config_drop_mode_rcq(nv, rcq, fbn->tx_pause, hdr_split);
 
+	hds_thresh = max(fbn->hds_thresh, FBNIC_HDR_BYTES_MIN);
 	rcq_ctl |= FIELD_PREP(FBNIC_QUEUE_RDE_CTL1_PADLEN_MASK, FBNIC_RX_PAD) |
 		   FIELD_PREP(FBNIC_QUEUE_RDE_CTL1_MAX_HDR_MASK, hds_thresh) |
 		   FIELD_PREP(FBNIC_QUEUE_RDE_CTL1_PAYLD_OFF_MASK,
diff --git a/drivers/net/ethernet/meta/fbnic/fbnic_txrx.h b/drivers/net/ethernet/meta/fbnic/fbnic_txrx.h
index b9560103ab86..980965274079 100644
--- a/drivers/net/ethernet/meta/fbnic/fbnic_txrx.h
+++ b/drivers/net/ethernet/meta/fbnic/fbnic_txrx.h
@@ -66,7 +66,7 @@ struct fbnic_net;
 	(4096 - FBNIC_RX_HROOM - FBNIC_RX_TROOM - FBNIC_RX_PAD)
 #define FBNIC_HDS_THRESH_DEFAULT \
 	(1536 - FBNIC_RX_PAD)
-#define FBNIC_HDR_BYTES_MIN		128
+#define FBNIC_HDR_BYTES_MIN		256
 
 struct fbnic_pkt_buff {
 	struct xdp_buff buff;
diff --git a/tools/testing/selftests/drivers/net/hw/devmem.py b/tools/testing/selftests/drivers/net/hw/devmem.py
index 45c2d49d55b6..ee863e90d1e0 100755
--- a/tools/testing/selftests/drivers/net/hw/devmem.py
+++ b/tools/testing/selftests/drivers/net/hw/devmem.py
@@ -63,12 +63,29 @@ def check_tx_chunks(cfg) -> None:
     ksft_eq(socat.stdout.strip(), "hello\nworld")
 
 
+def check_rx_hds(cfg) -> None:
+    """Test HDS splitting across payload sizes."""
+    require_devmem(cfg)
+
+    for size in [1, 8, 16, 32, 64, 128, 256, 512, 1024, 2048, 4096, 8192]:
+        port = rand_port()
+        listen_cmd = f"{cfg.bin_local} -L -l -f {cfg.ifname} -s {cfg.addr} -p {port}"
+
+        with bkg(listen_cmd, exit_wait=True) as ncdevmem:
+            wait_port_listen(port)
+            cmd(f"dd if=/dev/zero bs={size} count=1 2>/dev/null | " +
+                f"socat -b {size} -u - TCP{cfg.addr_ipver}:{cfg.baddr}:{port},nodelay",
+                host=cfg.remote, shell=True)
+
+        ksft_eq(ncdevmem.ret, 0, f"HDS failed for payload size {size}")
+
+
 def main() -> None:
     with NetDrvEpEnv(__file__) as cfg:
         cfg.bin_local = path.abspath(path.dirname(__file__) + "/ncdevmem")
         cfg.bin_remote = cfg.remote.deploy(cfg.bin_local)
 
-        ksft_run([check_rx, check_tx, check_tx_chunks],
+        ksft_run([check_rx, check_tx, check_tx_chunks, check_rx_hds],
                  args=(cfg, ))
     ksft_exit()
 
diff --git a/tools/testing/selftests/drivers/net/hw/ncdevmem.c b/tools/testing/selftests/drivers/net/hw/ncdevmem.c
index 16864c844108..e098d6534c3c 100644
--- a/tools/testing/selftests/drivers/net/hw/ncdevmem.c
+++ b/tools/testing/selftests/drivers/net/hw/ncdevmem.c
@@ -98,6 +98,7 @@ static unsigned int ifindex;
 static unsigned int dmabuf_id;
 static uint32_t tx_dmabuf_id;
 static int waittime_ms = 500;
+static bool fail_on_linear;
 
 /* System state loaded by current_config_load() */
 #define MAX_FLOWS	8
@@ -975,6 +976,11 @@ static int do_server(struct memory_buffer *mem)
 					"SCM_DEVMEM_LINEAR. dmabuf_cmsg->frag_size=%u\n",
 					dmabuf_cmsg->frag_size);
 
+				if (fail_on_linear) {
+					pr_err("received SCM_DEVMEM_LINEAR but --fail-on-linear (-L) set");
+					goto err_close_client;
+				}
+
 				continue;
 			}
 
@@ -1398,8 +1404,11 @@ int main(int argc, char *argv[])
 	int is_server = 0, opt;
 	int ret, err = 1;
 
-	while ((opt = getopt(argc, argv, "ls:c:p:v:q:t:f:z:")) != -1) {
+	while ((opt = getopt(argc, argv, "Lls:c:p:v:q:t:f:z:")) != -1) {
 		switch (opt) {
+		case 'L':
+			fail_on_linear = true;
+			break;
 		case 'l':
 			is_server = 1;
 			break;