The branch main has been updated by kbowling:

URL: 
https://cgit.FreeBSD.org/src/commit/?id=350211ab1782a68190754dcbdbcc7c9169ce22cb

commit 350211ab1782a68190754dcbdbcc7c9169ce22cb
Author:     Kevin Bowling <[email protected]>
AuthorDate: 2026-07-29 07:59:53 +0000
Commit:     Kevin Bowling <[email protected]>
CommitDate: 2026-07-30 05:06:33 +0000

    igb: Update only changed IOV multicast hashes
    
    Build the aggregate PF/VF multicast bitmap in software and compare it
    with the e1000 MTA shadow. Write only registers whose desired value
    changed, while forcing a complete write after PF reset invalidates the
    hardware table.
    
    This bounds alternating VF multicast updates without NACKing them.
    Linux igbvf and DPDK ignore multicast reply status, so a command-rate
    limiter could otherwise acknowledge configuration while leaving
    hardware state stale.
    
    Sponsored by:   BBOX.io
---
 sys/dev/e1000/if_em.c      |  3 ++-
 sys/dev/e1000/if_em.h      |  1 +
 sys/dev/e1000/if_igb_iov.c | 37 +++++++++++++++++++++++++++++--------
 3 files changed, 32 insertions(+), 9 deletions(-)

diff --git a/sys/dev/e1000/if_em.c b/sys/dev/e1000/if_em.c
index 0f60178ae3c8..4612653cf1bc 100644
--- a/sys/dev/e1000/if_em.c
+++ b/sys/dev/e1000/if_em.c
@@ -2554,7 +2554,8 @@ em_if_multi_set(if_ctx_t ctx)
                return;
        }
 
-       if (mcnt < MAX_NUM_MULTICAST_ADDRESSES)
+       if (mcnt < MAX_NUM_MULTICAST_ADDRESSES &&
+           !igb_iov_enabled(sc))
                e1000_update_mc_addr_list(&sc->hw, mta, mcnt);
 
        reg_rctl = E1000_READ_REG(&sc->hw, E1000_RCTL);
diff --git a/sys/dev/e1000/if_em.h b/sys/dev/e1000/if_em.h
index 93ddf0bfc25a..1692fdf41295 100644
--- a/sys/dev/e1000/if_em.h
+++ b/sys/dev/e1000/if_em.h
@@ -611,6 +611,7 @@ struct e1000_softc {
        u16                     num_vf_mac_filters;
        u16                     pool;
        bool                    iov_hw_active;
+       bool                    iov_mta_valid;
        bool                    iov_mbx_retry_initialized;
        bool                    iov_pf_mdd_blocked;
        bool                    iov_pf_vlan_promisc;
diff --git a/sys/dev/e1000/if_igb_iov.c b/sys/dev/e1000/if_igb_iov.c
index 1f66f9084e1a..8b8dfcd0a8f6 100644
--- a/sys/dev/e1000/if_igb_iov.c
+++ b/sys/dev/e1000/if_igb_iov.c
@@ -557,6 +557,7 @@ igb_iov_reset_prepare(struct e1000_softc *sc)
        sc->iov_hw_active = false;
        if (sc->iov_mbx_retry_initialized)
                callout_stop(&sc->iov_mbx_retry);
+       sc->iov_mta_valid = false;
        sc->iov_vfta_valid = false;
        atomic_readandclear_32(&sc->iov_mdd_cause);
        atomic_readandclear_32(&sc->iov_pending);
@@ -568,8 +569,10 @@ igb_iov_rebuild_mta(struct e1000_softc *sc)
 {
        struct e1000_hw *hw;
        struct igb_vf *vf;
-       u32 mta;
+       u32 hash_bit, hash_reg, hash_value;
+       u32 mta[MAX_MTA_REG] = {};
        u16 hash;
+       bool changed;
        int i, j, mcnt;
 
        if (!igb_iov_enabled(sc))
@@ -580,22 +583,38 @@ igb_iov_rebuild_mta(struct e1000_softc *sc)
            ETHER_ADDR_LEN * MAX_NUM_MULTICAST_ADDRESSES);
        mcnt = if_foreach_llmaddr(iflib_get_ifp(sc->ctx),
            igb_iov_copy_maddr, sc->mta);
-       e1000_update_mc_addr_list(hw, sc->mta,
-           min(mcnt, MAX_NUM_MULTICAST_ADDRESSES));
+       mcnt = min(mcnt, MAX_NUM_MULTICAST_ADDRESSES);
+       for (i = 0; i < mcnt; i++) {
+               hash_value = e1000_hash_mc_addr(hw,
+                   &sc->mta[i * ETHER_ADDR_LEN]);
+               hash_reg = (hash_value >> 5) &
+                   (hw->mac.mta_reg_count - 1);
+               hash_bit = hash_value & 0x1f;
+               mta[hash_reg] |= 1U << hash_bit;
+       }
        for (i = 0; i < sc->num_vfs; i++) {
                vf = &sc->vfs[i];
                if (!(vf->flags & IGB_VF_ACTIVE))
                        continue;
                for (j = 0; j < vf->mc_count; j++) {
                        hash = vf->mc_hashes[j] & 0xfff;
-                       mta = E1000_READ_REG_ARRAY(hw, E1000_MTA,
-                           (hash >> 5) & 0x7f);
-                       mta |= 1U << (hash & 0x1f);
-                       E1000_WRITE_REG_ARRAY(hw, E1000_MTA,
-                           (hash >> 5) & 0x7f, mta);
+                       mta[(hash >> 5) & (hw->mac.mta_reg_count - 1)] |=
+                           1U << (hash & 0x1f);
                }
                igb_iov_configure_vmolr(sc, vf);
        }
+
+       changed = false;
+       for (i = hw->mac.mta_reg_count - 1; i >= 0; i--) {
+               if (sc->iov_mta_valid && hw->mac.mta_shadow[i] == mta[i])
+                       continue;
+               hw->mac.mta_shadow[i] = mta[i];
+               E1000_WRITE_REG_ARRAY(hw, E1000_MTA, i, mta[i]);
+               changed = true;
+       }
+       if (changed)
+               E1000_WRITE_FLUSH(hw);
+       sc->iov_mta_valid = true;
 }
 
 static int
@@ -1641,6 +1660,7 @@ igb_if_iov_init(if_ctx_t ctx, u16 num_vfs, const nvlist_t 
*config)
        for (i = 0; i < sc->num_vf_mac_filters; i++)
                sc->vf_mac_filters[i].rar_index = i + 1;
        sc->pool = num_vfs;
+       sc->iov_mta_valid = false;
        sc->iov_pf_mdd_blocked = false;
        sc->tx_queues[0].txr.me = sc->pool;
        sc->rx_queues[0].rxr.me = sc->pool;
@@ -1717,6 +1737,7 @@ igb_if_iov_uninit(if_ctx_t ctx)
        sc->num_vfs = 0;
        sc->num_vf_mac_filters = 0;
        sc->pool = 0;
+       sc->iov_mta_valid = false;
        sc->iov_pf_mdd_blocked = false;
        sc->iov_pf_vlan_promisc = false;
        sc->iov_vfta_valid = false;

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