From bbeb3bfbffe0279fa47c041658b037fb38a93965 Mon Sep 17 00:00:00 2001 From: Bobby Eshleman Date: Wed, 11 Feb 2026 17:00:41 -0800 Subject: [PATCH 1/4] eth: fbnic: set FBNIC_QUEUE_RDE_CTL0_EN_HDR_SPLIT on RDE_CTL0 Fix EN_HDR_SPLIT configuration by writing the field to RDE_CTL0 instead of RDE_CTL1. Because drop mode configuration and header splitting enablement both use RDE_CTL0, we consolidate these configurations into the single function fbnic_config_drop_mode. Fixes: 2b30fc01a6c7 ("eth: fbnic: Add support for HDS configuration") Signed-off-by: Bobby Eshleman Acked-by: Mohsin Bashir Link: https://patch.msgid.link/20260211-fbnic-tcp-hds-fixes-v1-1-55d050e6f606@meta.com Signed-off-by: Paolo Abeni --- drivers/net/ethernet/meta/fbnic/fbnic_txrx.c | 25 +++++++++++--------- 1 file changed, 14 insertions(+), 11 deletions(-) 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 @@ static void fbnic_enable_bdq(struct fbnic_ring *hpq, struct fbnic_ring *ppq) } 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, From bd254115f38db3c046332bb62e8719e0dc7c2b53 Mon Sep 17 00:00:00 2001 From: Bobby Eshleman Date: Wed, 11 Feb 2026 17:00:42 -0800 Subject: [PATCH 2/4] eth: fbnic: increase FBNIC_HDR_BYTES_MIN from 128 to 256 bytes Increase FBNIC_HDR_BYTES_MIN from 128 to 256 bytes. The previous minimum was too small to guarantee that very long L2+L3+L4 headers always fit within the header buffer. When EN_HDR_SPLIT is disabled and a packet exceeds MAX_HEADER_BYTES, splitting occurs at that byte offset instead of the header boundary, resulting in some of the header landing in the payload page. The increased minimum ensures headers always fit with the MAX_HEADER_BYTES cut off and land in the header page. Fixes: 2b30fc01a6c7 ("eth: fbnic: Add support for HDS configuration") Signed-off-by: Bobby Eshleman Acked-by: Mohsin Bashir Link: https://patch.msgid.link/20260211-fbnic-tcp-hds-fixes-v1-2-55d050e6f606@meta.com Signed-off-by: Paolo Abeni --- drivers/net/ethernet/meta/fbnic/fbnic_txrx.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) 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; From 0f30a31b55c4179fc55613a75ef41d496687d465 Mon Sep 17 00:00:00 2001 From: Bobby Eshleman Date: Wed, 11 Feb 2026 17:00:43 -0800 Subject: [PATCH 3/4] eth: fbnic: set DMA_HINT_L4 for all flows fbnic always advertises ETHTOOL_TCP_DATA_SPLIT_ENABLED via ethtool .get_ringparam. To enable proper splitting for all flow types, even for IP/Ethernet flows, this patch sets DMA_HINT_L4 unconditionally for all RSS and NFC flow steering rules. According to the spec, L4 falls back to L3 if no valid L4 is found, and L3 falls back to L2 if no L3 is found. This makes sure that the correct header boundary is used regardless of traffic type. This is important for zero-copy use cases where we must ensure that all ZC packets are split correctly. Fixes: 2b30fc01a6c7 ("eth: fbnic: Add support for HDS configuration") Signed-off-by: Bobby Eshleman Link: https://patch.msgid.link/20260211-fbnic-tcp-hds-fixes-v1-3-55d050e6f606@meta.com Signed-off-by: Paolo Abeni --- drivers/net/ethernet/meta/fbnic/fbnic_ethtool.c | 3 +++ drivers/net/ethernet/meta/fbnic/fbnic_rpc.c | 5 ++--- 2 files changed, 5 insertions(+), 3 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 @@ static int fbnic_set_cls_rule_ins(struct fbnic_net *fbn, 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); From e7a3c1adc127f9f91a35169d34f7471d417d72a6 Mon Sep 17 00:00:00 2001 From: Bobby Eshleman Date: Wed, 11 Feb 2026 17:00:44 -0800 Subject: [PATCH 4/4] selftests: drv-net: add HDS payload sweep test for devmem TCP Add check_rx_hds test that verifies header/data split works across payload sizes. The test sweeps payload sizes from 1 byte to 8KB, if any data propagates up to userspace as SCM_DEVMEM_LINEAR, then the test fails. This shows that regardless of payload size, ncdevmem's configuration of hds-thresh to 0 is respected. Add -L (--fail-on-linear) flag to ncdevmem that causes the receiver to fail if any SCM_DEVMEM_LINEAR cmsg is received. Use socat option for fixed block sizing and tcp nodelay to disable nagle's algo to avoid buffering. Signed-off-by: Bobby Eshleman Link: https://patch.msgid.link/20260211-fbnic-tcp-hds-fixes-v1-4-55d050e6f606@meta.com Signed-off-by: Paolo Abeni --- .../selftests/drivers/net/hw/devmem.py | 19 ++++++++++++++++++- .../selftests/drivers/net/hw/ncdevmem.c | 11 ++++++++++- 2 files changed, 28 insertions(+), 2 deletions(-) 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;