git: f908fbb9b267 - main - iavf: Honor PF-negotiated RSS sizes

The branch main has been updated by kbowling:

URL: https://cgit.FreeBSD.org/src/commit/?id=f908fbb9b2671cbc6cf366c8287899940e3c88b5

commit f908fbb9b2671cbc6cf366c8287899940e3c88b5
Author:     Kevin Bowling <kbowling@FreeBSD.org>
AuthorDate: 2026-09-16 23:34:27 +0000
Commit:     Kevin Bowling <kbowling@FreeBSD.org>
CommitDate: 2026-09-17 00:20:23 +0000

    iavf: Honor PF-negotiated RSS sizes
    
    Use the key and lookup table lengths returned by GET_VF_RESOURCES when
    configuring RSS through virtchnl, as DPDK does.  The Windows E835 PF
    advertises a 40-byte key and rejects our fixed 52-byte CONFIG_RSS_KEY
    request, leaving receive traffic on queue zero.
    
    Validate the negotiated lengths before constructing AdminQ messages and
    publish the lookup table size to iflib.  Preserve register-mode RSS
    selection and its fixed hardware sizes.  Use aligned, zero initialized
    key storage so an RSS kernel's 40-byte key does not leave an uninitialized
    tail when the PF requests 52 bytes.
    
    Validation: normal and RSS enabled iavf module builds passed.  On an E835
    VF under Hyper-V Server 2025, repeated IPv4 and IPv6 receive tests used all
    three configured guest RX queues in both transparent hn and non-transparent
    lagg modes.  The RSS key rejection disappeared, IPv4 transmit tests passed,
    and no TX watchdog fired.  Each traffic case used three runs of 16 streams.
    
    Obtained from:  DPDK (negotiated RSS sizing)
    MFC after:      2 weeks
    Sponsored by:   BBOX.io
---
 sys/dev/iavf/iavf_lib.c       | 15 ++++++++++++++-
 sys/dev/iavf/iavf_vc_common.c |  8 ++++----
 sys/dev/iavf/if_iavf_iflib.c  |  3 +++
 3 files changed, 21 insertions(+), 5 deletions(-)

diff --git a/sys/dev/iavf/iavf_lib.c b/sys/dev/iavf/iavf_lib.c
index e7cd9222bd68..9d6d64829268 100644
--- a/sys/dev/iavf/iavf_lib.c
+++ b/sys/dev/iavf/iavf_lib.c
@@ -520,6 +520,19 @@ iavf_get_vsi_res_from_vf_res(struct iavf_sc *sc)
 	device_t dev = sc->dev;
 
 	sc->vsi_res = NULL;
+	/* Bound PF-sized messages and preserve iflib's table-mask assumption. */
+	if ((sc->vf_res->vf_cap_flags & (VIRTCHNL_VF_OFFLOAD_RSS_REG |
+	    VIRTCHNL_VF_OFFLOAD_RSS_PF)) == VIRTCHNL_VF_OFFLOAD_RSS_PF &&
+	    (sc->vf_res->rss_key_size == 0 ||
+	    sc->vf_res->rss_key_size > IAVF_RSS_KEY_SIZE ||
+	    sc->vf_res->rss_lut_size == 0 ||
+	    sc->vf_res->rss_lut_size > IAVF_AQ_BUF_SZ -
+	    sizeof(struct virtchnl_rss_lut) + 1 ||
+	    !powerof2(sc->vf_res->rss_lut_size))) {
+		device_printf(dev, "Unsupported PF RSS sizes: key %u lut %u\n",
+		    sc->vf_res->rss_key_size, sc->vf_res->rss_lut_size);
+		return (EINVAL);
+	}
 
 	for (int i = 0; i < sc->vf_res->num_vsis; i++) {
 		/* XXX: We only use the first VSI we find */
@@ -1090,7 +1103,7 @@ iavf_config_rss_reg(struct iavf_sc *sc)
 	u32		lut = 0;
 	u64		set_hena = 0, hena;
 	int		i, j, que_id;
-	u32		rss_seed[IAVF_RSS_KEY_SIZE_REG];
+	u32		rss_seed[IAVF_RSS_KEY_SIZE_REG] = {0};
 	u32		rss_hash_config;
 
 	/* Don't set up RSS if using a single queue */
diff --git a/sys/dev/iavf/iavf_vc_common.c b/sys/dev/iavf/iavf_vc_common.c
index 37b085f7ef08..9470d764d610 100644
--- a/sys/dev/iavf/iavf_vc_common.c
+++ b/sys/dev/iavf/iavf_vc_common.c
@@ -724,17 +724,17 @@ iavf_config_rss_key(struct iavf_sc *sc)
 {
 	struct virtchnl_rss_key *rss_key_msg;
 	int msg_len, key_length;
-	u8		rss_seed[IAVF_RSS_KEY_SIZE];
+	u32		rss_seed[IAVF_RSS_KEY_SIZE_REG] = {0};
 
 #ifdef RSS
 	/* Fetch the configured RSS key */
 	rss_getkey((uint8_t *) &rss_seed);
 #else
-	iavf_get_default_rss_key((u32 *)rss_seed);
+	iavf_get_default_rss_key(rss_seed);
 #endif
 
 	/* Send the fetched key */
-	key_length = IAVF_RSS_KEY_SIZE;
+	key_length = sc->vf_res->rss_key_size;
 	msg_len = sizeof(struct virtchnl_rss_key) + (sizeof(u8) * key_length) - 1;
 	rss_key_msg = (struct virtchnl_rss_key *)
 	    malloc(msg_len, M_IAVF, M_NOWAIT | M_ZERO);
@@ -804,7 +804,7 @@ iavf_config_rss_lut(struct iavf_sc *sc)
 	u32 lut;
 	int i, que_id;
 
-	lut_length = IAVF_RSS_VSI_LUT_SIZE;
+	lut_length = sc->vf_res->rss_lut_size;
 	msg_len = sizeof(struct virtchnl_rss_lut) + (lut_length * sizeof(u8)) - 1;
 	rss_lut_msg = (struct virtchnl_rss_lut *)
 	    malloc(msg_len, M_IAVF, M_NOWAIT | M_ZERO);
diff --git a/sys/dev/iavf/if_iavf_iflib.c b/sys/dev/iavf/if_iavf_iflib.c
index 25aee839648a..0838eabbec1f 100644
--- a/sys/dev/iavf/if_iavf_iflib.c
+++ b/sys/dev/iavf/if_iavf_iflib.c
@@ -401,6 +401,9 @@ iavf_if_attach_pre(if_ctx_t ctx)
 	scctx->isc_tx_tso_size_max = IAVF_TSO_SIZE;
 	scctx->isc_tx_tso_segsize_max = IAVF_MAX_DMA_SEG_SIZE;
 	scctx->isc_rss_table_size = IAVF_RSS_VSI_LUT_SIZE;
+	if ((sc->vf_res->vf_cap_flags & (VIRTCHNL_VF_OFFLOAD_RSS_REG |
+	    VIRTCHNL_VF_OFFLOAD_RSS_PF)) == VIRTCHNL_VF_OFFLOAD_RSS_PF)
+		scctx->isc_rss_table_size = sc->vf_res->rss_lut_size;
 	scctx->isc_capabilities = scctx->isc_capenable = IAVF_CAPS;
 	scctx->isc_tx_csum_flags = CSUM_OFFLOAD;