linux-kernel - [PATCH net-next v2] idpf: export RX hardware timestamping information to XDP

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Message-ID: <20251218022948.3288897-1-almasrymina@google.com>
Date: Thu, 18 Dec 2025 02:29:36 +0000
From: Mina Almasry <almasrymina@...gle.com>
To: netdev@...r.kernel.org, bpf@...r.kernel.org, linux-kernel@...r.kernel.org
Cc: YiFei Zhu <zhuyifei@...gle.com>, Alexei Starovoitov <ast@...nel.org>, 
	Daniel Borkmann <daniel@...earbox.net>, "David S. Miller" <davem@...emloft.net>, 
	Jakub Kicinski <kuba@...nel.org>, Jesper Dangaard Brouer <hawk@...nel.org>, 
	John Fastabend <john.fastabend@...il.com>, Stanislav Fomichev <sdf@...ichev.me>, 
	Tony Nguyen <anthony.l.nguyen@...el.com>, Przemek Kitszel <przemyslaw.kitszel@...el.com>, 
	Andrew Lunn <andrew+netdev@...n.ch>, Eric Dumazet <edumazet@...gle.com>, 
	Paolo Abeni <pabeni@...hat.com>, Alexander Lobakin <aleksander.lobakin@...el.com>, 
	Richard Cochran <richardcochran@...il.com>, intel-wired-lan@...ts.osuosl.org, 
	Mina Almasry <almasrymina@...gle.com>, 
	Aleksandr Loktionov <aleksandr.loktionov@...el.com>
Subject: [PATCH net-next v2] idpf: export RX hardware timestamping information
 to XDP

From: YiFei Zhu <zhuyifei@...gle.com>

The logic is similar to idpf_rx_hwtstamp, but the data is exported
as a BPF kfunc instead of appended to an skb.

A idpf_queue_has(PTP, rxq) condition is added to check the queue
supports PTP similar to idpf_rx_process_skb_fields.

Cc: intel-wired-lan@...ts.osuosl.org

Signed-off-by: YiFei Zhu <zhuyifei@...gle.com>
Signed-off-by: Mina Almasry <almasrymina@...gle.com>
Reviewed-by: Aleksandr Loktionov <aleksandr.loktionov@...el.com>

---

v2: https://lore.kernel.org/netdev/20251122140839.3922015-1-almasrymina@google.com/
- Fixed alphabetical ordering
- Use the xdp desc type instead of virtchnl one (required some added
  helpers)

---
 drivers/net/ethernet/intel/idpf/xdp.c | 29 +++++++++++++++++++++++++++
 drivers/net/ethernet/intel/idpf/xdp.h | 17 ++++++++++++++++
 2 files changed, 46 insertions(+)

diff --git a/drivers/net/ethernet/intel/idpf/xdp.c b/drivers/net/ethernet/intel/idpf/xdp.c
index 958d16f87424..7744d6898f74 100644
--- a/drivers/net/ethernet/intel/idpf/xdp.c
+++ b/drivers/net/ethernet/intel/idpf/xdp.c
@@ -2,6 +2,7 @@
 /* Copyright (C) 2025 Intel Corporation */
 
 #include "idpf.h"
+#include "idpf_ptp.h"
 #include "idpf_virtchnl.h"
 #include "xdp.h"
 #include "xsk.h"
@@ -391,8 +392,36 @@ static int idpf_xdpmo_rx_hash(const struct xdp_md *ctx, u32 *hash,
 				    pt);
 }
 
+static int idpf_xdpmo_rx_timestamp(const struct xdp_md *ctx, u64 *timestamp)
+{
+	const struct libeth_xdp_buff *xdp = (typeof(xdp))ctx;
+	struct idpf_xdp_rx_desc desc __uninitialized;
+	const struct idpf_rx_queue *rxq;
+	u64 cached_time, ts_ns;
+	u32 ts_high;
+
+	idpf_xdp_get_qw1(&desc, xdp->desc);
+	rxq = libeth_xdp_buff_to_rq(xdp, typeof(*rxq), xdp_rxq);
+
+	if (!idpf_queue_has(PTP, rxq))
+		return -ENODATA;
+	if (!(idpf_xdp_rx_ts_low(&desc) & VIRTCHNL2_RX_FLEX_TSTAMP_VALID))
+		return -ENODATA;
+
+	cached_time = READ_ONCE(rxq->cached_phc_time);
+
+	idpf_xdp_get_qw3(&desc, xdp->desc);
+
+	ts_high = idpf_xdp_rx_ts_high(&desc);
+	ts_ns = idpf_ptp_tstamp_extend_32b_to_64b(cached_time, ts_high);
+
+	*timestamp = ts_ns;
+	return 0;
+}
+
 static const struct xdp_metadata_ops idpf_xdpmo = {
 	.xmo_rx_hash		= idpf_xdpmo_rx_hash,
+	.xmo_rx_timestamp	= idpf_xdpmo_rx_timestamp,
 };
 
 void idpf_xdp_set_features(const struct idpf_vport *vport)
diff --git a/drivers/net/ethernet/intel/idpf/xdp.h b/drivers/net/ethernet/intel/idpf/xdp.h
index 479f5ef3c604..86be6cae9689 100644
--- a/drivers/net/ethernet/intel/idpf/xdp.h
+++ b/drivers/net/ethernet/intel/idpf/xdp.h
@@ -112,11 +112,13 @@ struct idpf_xdp_rx_desc {
 	aligned_u64		qw1;
 #define IDPF_XDP_RX_BUF		GENMASK_ULL(47, 32)
 #define IDPF_XDP_RX_EOP		BIT_ULL(1)
+#define IDPF_XDP_RX_TS_LOW	GENMASK_ULL(31, 24)
 
 	aligned_u64		qw2;
 #define IDPF_XDP_RX_HASH	GENMASK_ULL(31, 0)
 
 	aligned_u64		qw3;
+#define IDPF_XDP_RX_TS_HIGH	GENMASK_ULL(63, 32)
 } __aligned(4 * sizeof(u64));
 static_assert(sizeof(struct idpf_xdp_rx_desc) ==
 	      sizeof(struct virtchnl2_rx_flex_desc_adv_nic_3));
@@ -128,6 +130,8 @@ static_assert(sizeof(struct idpf_xdp_rx_desc) ==
 #define idpf_xdp_rx_buf(desc)	FIELD_GET(IDPF_XDP_RX_BUF, (desc)->qw1)
 #define idpf_xdp_rx_eop(desc)	!!((desc)->qw1 & IDPF_XDP_RX_EOP)
 #define idpf_xdp_rx_hash(desc)	FIELD_GET(IDPF_XDP_RX_HASH, (desc)->qw2)
+#define idpf_xdp_rx_ts_low(desc)	FIELD_GET(IDPF_XDP_RX_TS_LOW, (desc)->qw1)
+#define idpf_xdp_rx_ts_high(desc)	FIELD_GET(IDPF_XDP_RX_TS_HIGH, (desc)->qw3)
 
 static inline void
 idpf_xdp_get_qw0(struct idpf_xdp_rx_desc *desc,
@@ -166,6 +170,19 @@ idpf_xdp_get_qw2(struct idpf_xdp_rx_desc *desc,
 #endif
 }
 
+static inline void
+idpf_xdp_get_qw3(struct idpf_xdp_rx_desc *desc,
+		 const struct virtchnl2_rx_flex_desc_adv_nic_3 *rxd)
+{
+#ifdef __LIBETH_WORD_ACCESS
+	desc->qw3 = ((const typeof(desc))rxd)->qw3;
+#else
+	desc->qw3 = ((u64)le32_to_cpu(rxd->ts_high) << 32) |
+		    ((u64)le16_to_cpu(rxd->fmd6) << 16) |
+		    le16_to_cpu(rxd->l2tag1);
+#endif
+}
+
 void idpf_xdp_set_features(const struct idpf_vport *vport);
 
 int idpf_xdp(struct net_device *dev, struct netdev_bpf *xdp);

base-commit: 8f7aa3d3c7323f4ca2768a9e74ebbe359c4f8f88
-- 
2.52.0.313.g674ac2bdf7-goog