git: 215fbb3974ab - stable/15 - ixl: verify flowid is valid before setting rsstype & flowid

The branch stable/15 has been updated by kbowling:

URL: https://cgit.FreeBSD.org/src/commit/?id=215fbb3974ab218d943a973aef0c93cdc19f7e10

commit 215fbb3974ab218d943a973aef0c93cdc19f7e10
Author:     Andrew Gallatin <gallatin@FreeBSD.org>
AuthorDate: 2026-01-05 17:02:23 +0000
Commit:     Kevin Bowling <kbowling@FreeBSD.org>
CommitDate: 2026-10-29 06:54:44 +0000

    ixl: verify flowid is valid before setting rsstype & flowid
    
    According to section 8.3.2.2.1 of the XL710 datasheet,
    FLTSTAT indicates if RSS hashing was used (or flow director
    or nothing) to arrive at the flowid it is reporting.
    We need to check this before reporting the flowid and setting the
    rss type. Not checking this allows invalid flowids (0s) to be
    reported for some TCP traffic (it seems to mostly impact incoming
    connections). This leads to the inp flowid being 0, and egress
    traffic being unbalanced (going to tx queue 0, and NIC 0 of an
    lacp bundle).
    
    Differential Revision: https://reviews.freebsd.org/D54442
    Reviewed by: adrian, kbowling
    Sponsored by: Netflix
    
    (cherry picked from commit ac1cd655f647cfd8e8d8c08da00f41abfce212a1)
---
 sys/dev/ixl/ixl_txrx.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/sys/dev/ixl/ixl_txrx.c b/sys/dev/ixl/ixl_txrx.c
index d015a93b5360..7ce1c24c814a 100644
--- a/sys/dev/ixl/ixl_txrx.c
+++ b/sys/dev/ixl/ixl_txrx.c
@@ -648,7 +648,7 @@ ixl_isc_rxd_pkt_get(void *arg, if_rxd_info_t ri)
 	struct ixl_rx_queue	*que = &vsi->rx_queues[ri->iri_qsidx];
 	struct rx_ring		*rxr = &que->rxr;
 	union i40e_rx_desc	*cur;
-	u32		status, error;
+	u32		status, error, fltstat;
 	u16		plen;
 	u64		qword;
 	u8		ptype;
@@ -704,8 +704,12 @@ ixl_isc_rxd_pkt_get(void *arg, if_rxd_info_t ri)
 
 	if ((scctx->isc_capenable & IFCAP_RXCSUM) != 0)
 		rxr->csum_errs += ixl_rx_checksum(ri, status, error, ptype);
-	ri->iri_flowid = le32toh(cur->wb.qword0.hi_dword.rss);
-	ri->iri_rsstype = ixl_ptype_to_hash(ptype);
+	fltstat = (status >> I40E_RX_DESC_STATUS_FLTSTAT_SHIFT);
+	if ((fltstat & I40E_RX_DESC_FLTSTAT_RSS_HASH) ==
+		I40E_RX_DESC_FLTSTAT_RSS_HASH) {
+		ri->iri_flowid = le32toh(cur->wb.qword0.hi_dword.rss);
+		ri->iri_rsstype = ixl_ptype_to_hash(ptype);
+	}
 	if (status & (1 << I40E_RX_DESC_STATUS_L2TAG1P_SHIFT)) {
 		ri->iri_vtag = le16toh(cur->wb.qword0.lo_dword.l2tag1);
 		ri->iri_flags |= M_VLANTAG;