git: 40a6ada9e614 - stable/14 - igb(4): Fix VLAN support on VFs

The branch stable/14 has been updated by kgalazka:

URL: https://cgit.FreeBSD.org/src/commit/?id=40a6ada9e614c1a6fd93e4164f7de416af1a23b2

commit 40a6ada9e614c1a6fd93e4164f7de416af1a23b2
Author:     Krzysztof Galazka <kgalazka@FreeBSD.org>
AuthorDate: 2025-11-17 15:30:26 +0000
Commit:     Krzysztof Galazka <kgalazka@FreeBSD.org>
CommitDate: 2025-11-28 20:59:24 +0000

    igb(4): Fix VLAN support on VFs
    
    Virtual Functions are considered untrusted and have no control
    over VLAN filtering configuration in HW. To allow using
    VLANs on VF intreface driver has to assume that VLAN HW Filtering
    is always enabled and pass requests for adding or removing VLAN
    tags to Physical Function driver using Mailbox API.
    
    Signed-off-by: Krzysztof Galazka <krzysztof.galazka@intel.com>
    
    Approved by:    kbowling (mentor)
    Reviewed by:    erj (previous version)
    Tested by:      gowtham.kumar.ks_intel.com
    Sponsored by:   Intel Corporation
    Differential Revision:  https://reviews.freebsd.org/D53245
    
    (cherry picked from commit 1839526b7315cae62efbd2d1493e6243439effcb)
---
 sys/dev/e1000/if_em.c | 34 ++++++++++++++++++++--------------
 1 file changed, 20 insertions(+), 14 deletions(-)

diff --git a/sys/dev/e1000/if_em.c b/sys/dev/e1000/if_em.c
index 9040949b36c7..ce4269728903 100644
--- a/sys/dev/e1000/if_em.c
+++ b/sys/dev/e1000/if_em.c
@@ -4048,7 +4048,15 @@ em_if_vlan_register(if_ctx_t ctx, u16 vtag)
 	bit = vtag & 0x1F;
 	sc->shadow_vfta[index] |= (1 << bit);
 	++sc->num_vlans;
-	em_if_vlan_filter_write(sc);
+	if (!sc->vf_ifp)
+		em_if_vlan_filter_write(sc);
+	else
+		/*
+		 * Physical funtion may reject registering VLAN
+		 * but we have no way to inform the stack
+		 * about that.
+		 */
+		e1000_vfta_set_vf(&sc->hw, vtag, true);
 }
 
 static void
@@ -4061,7 +4069,10 @@ em_if_vlan_unregister(if_ctx_t ctx, u16 vtag)
 	bit = vtag & 0x1F;
 	sc->shadow_vfta[index] &= ~(1 << bit);
 	--sc->num_vlans;
-	em_if_vlan_filter_write(sc);
+	if (!sc->vf_ifp)
+		em_if_vlan_filter_write(sc);
+	else
+		e1000_vfta_set_vf(&sc->hw, vtag, false);
 }
 
 static bool
@@ -4119,22 +4130,15 @@ em_if_vlan_filter_write(struct e1000_softc *sc)
 {
 	struct e1000_hw *hw = &sc->hw;
 
-	if (sc->vf_ifp)
-		return;
+	KASSERT(!sc->vf_ifp, ("VLAN filter write on VF\n"));
 
 	/* Disable interrupts for lem(4) devices during the filter change */
 	if (hw->mac.type < em_mac_min)
 		em_if_intr_disable(sc->ctx);
 
 	for (int i = 0; i < EM_VFTA_SIZE; i++)
-		if (sc->shadow_vfta[i] != 0) {
-			/* XXXKB: incomplete VF support, we returned above */
-			if (sc->vf_ifp)
-				e1000_vfta_set_vf(hw, sc->shadow_vfta[i],
-				    true);
-			else
-				e1000_write_vfta(hw, i, sc->shadow_vfta[i]);
-		}
+		if (sc->shadow_vfta[i] != 0)
+			e1000_write_vfta(hw, i, sc->shadow_vfta[i]);
 
 	/* Re-enable interrupts for lem-class devices */
 	if (hw->mac.type < em_mac_min)
@@ -4149,8 +4153,10 @@ em_setup_vlan_hw_support(if_ctx_t ctx)
 	if_t ifp = iflib_get_ifp(ctx);
 	u32 reg;
 
-	/* XXXKB: Return early if we are a VF until VF decap and filter
-	 * management is ready and tested.
+	/*
+	 * Only PFs have control over VLAN HW filtering
+	 * configuration. VFs have to act as if it's always
+	 * enabled.
 	 */
 	if (sc->vf_ifp)
 		return;