igc: Fix HW RX timestamp when passed by ZC XDP

Fixes HW RX timestamp in the following scenario:
- AF_PACKET socket with enabled HW RX timestamps is created
- AF_XDP socket with enabled zero copy is created
- frame is forwarded to the BPF program, where the timestamp should
  still be readable (extracted by igc_xdp_rx_timestamp(), kfunc
  behind bpf_xdp_metadata_rx_timestamp())
- the frame got XDP_PASS from BPF program, redirecting to the stack
- AF_PACKET socket receives the frame with HW RX timestamp

Moves the skb timestamp setting from igc_dispatch_skb_zc() to
igc_construct_skb_zc() so that igc_construct_skb_zc() is similar to
igc_construct_skb().

This issue can also be reproduced by running:
 # tools/testing/selftests/bpf/xdp_hw_metadata enp1s0
When a frame with the wrong port 9092 (instead of 9091) is used:
 # echo -n xdp | nc -u -q1 192.168.10.9 9092
then the RX timestamp is missing and xdp_hw_metadata prints:
 skb hwtstamp is not found!

With this fix or when copy mode is used:
 # tools/testing/selftests/bpf/xdp_hw_metadata -c enp1s0
then RX timestamp is found and xdp_hw_metadata prints:
 found skb hwtstamp = 1736509937.852786132

Fixes: 069b142f5819 ("igc: Add support for PTP .getcyclesx64()")
Signed-off-by: Zdenek Bouska <zdenek.bouska@siemens.com>
Acked-by: Vinicius Costa Gomes <vinicius.gomes@intel.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Reviewed-by: Florian Bezdeka <florian.bezdeka@siemens.com>
Reviewed-by: Song Yoong Siang <yoong.siang.song@intel.com>
Tested-by: Mor Bar-Gabay <morx.bar.gabay@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>

diff --git a/drivers/net/ethernet/intel/igc/igc_main.c b/drivers/net/ethernet/intel/igc/igc_main.c
index 56a35d58e7a6290606931f4ab4cb814cbe30f146..21f318f12a8d6f3361bc7010c05106c771ab7c1a 100644 (file)
--- a/drivers/net/ethernet/intel/igc/igc_main.c
+++ b/drivers/net/ethernet/intel/igc/igc_main.c
@@ -2701,8 +2701,9 @@ static int igc_clean_rx_irq(struct igc_q_vector *q_vector, const int budget)
 }
 
 static struct sk_buff *igc_construct_skb_zc(struct igc_ring *ring,
-                                           struct xdp_buff *xdp)
+                                           struct igc_xdp_buff *ctx)
 {
+       struct xdp_buff *xdp = &ctx->xdp;
        unsigned int totalsize = xdp->data_end - xdp->data_meta;
        unsigned int metasize = xdp->data - xdp->data_meta;
        struct sk_buff *skb;
@@ -2721,27 +2722,28 @@ static struct sk_buff *igc_construct_skb_zc(struct igc_ring *ring,
                __skb_pull(skb, metasize);
        }
 
+       if (ctx->rx_ts) {
+               skb_shinfo(skb)->tx_flags |= SKBTX_HW_TSTAMP_NETDEV;
+               skb_hwtstamps(skb)->netdev_data = ctx->rx_ts;
+       }
+
        return skb;
 }
 
 static void igc_dispatch_skb_zc(struct igc_q_vector *q_vector,
                                union igc_adv_rx_desc *desc,
-                               struct xdp_buff *xdp,
-                               ktime_t timestamp)
+                               struct igc_xdp_buff *ctx)
 {
        struct igc_ring *ring = q_vector->rx.ring;
        struct sk_buff *skb;
 
-       skb = igc_construct_skb_zc(ring, xdp);
+       skb = igc_construct_skb_zc(ring, ctx);
        if (!skb) {
                ring->rx_stats.alloc_failed++;
                set_bit(IGC_RING_FLAG_RX_ALLOC_FAILED, &ring->flags);
                return;
        }
 
-       if (timestamp)
-               skb_hwtstamps(skb)->hwtstamp = timestamp;
-
        if (igc_cleanup_headers(ring, desc, skb))
                return;
 
@@ -2777,7 +2779,6 @@ static int igc_clean_rx_irq_zc(struct igc_q_vector *q_vector, const int budget)
                union igc_adv_rx_desc *desc;
                struct igc_rx_buffer *bi;
                struct igc_xdp_buff *ctx;
-               ktime_t timestamp = 0;
                unsigned int size;
                int res;
 
@@ -2807,6 +2808,8 @@ static int igc_clean_rx_irq_zc(struct igc_q_vector *q_vector, const int budget)
                         */
                        bi->xdp->data_meta += IGC_TS_HDR_LEN;
                        size -= IGC_TS_HDR_LEN;
+               } else {
+                       ctx->rx_ts = NULL;
                }
 
                bi->xdp->data_end = bi->xdp->data + size;
@@ -2815,7 +2818,7 @@ static int igc_clean_rx_irq_zc(struct igc_q_vector *q_vector, const int budget)
                res = __igc_xdp_run_prog(adapter, prog, bi->xdp);
                switch (res) {
                case IGC_XDP_PASS:
-                       igc_dispatch_skb_zc(q_vector, desc, bi->xdp, timestamp);
+                       igc_dispatch_skb_zc(q_vector, desc, ctx);
                        fallthrough;
                case IGC_XDP_CONSUMED:
                        xsk_buff_free(bi->xdp);