ixv(4) for SR-IOV on Intel NICs does not work

I've tried ixv(4) with 82599ES and X540-AT2 NICs and it does not see any 
traffic. I tried 10.1_STABLE and 11.99.5.

For 82599:

ixv0 at pci0 dev 8 function 0: Intel(R) PRO/10GbE Virtual Function Network Driver, Version - 2.0.1-k
ixv0: clearing prefetchable bit
ixv0: device 82599 VF
ixv0: Mailbox API 1.3
ixv0: Using MSI-X interrupts with 3 vectors
ixv0: for TX/RX, interrupting at msix0 vec 0, bound queue 0 to cpu 0
ixv0: for TX/RX, interrupting at msix0 vec 1, bound queue 1 to cpu 1
ixv0: for link, interrupting at msix0 vec 2, affinity to cpu 2
ixv0: Ethernet address 86:45:bd:be:6b:0e
ixv0: feature cap 0x81<VF,LEGACY_TX>
ixv0: feature ena 0x1<VF>

For X540:

ixv0 at pci0 dev 8 function 0: Intel(R) PRO/10GbE Virtual Function Network Driver, Version - 2.0.1-k
ixv0: device X540 VF
ixv0: Mailbox API 1.3
ixv0: Using MSI-X interrupts with 3 vectors
ixv0: for TX/RX, interrupting at msix0 vec 0, bound queue 0 to cpu 0
ixv0: for TX/RX, interrupting at msix0 vec 1, bound queue 1 to cpu 1
ixv0: for link, interrupting at msix0 vec 2, affinity to cpu 2
ixv0: Ethernet address 86:45:bd:be:6b:0e
ixv0: feature cap 0x81<VF,LEGACY_TX>
ixv0: feature ena 0x1<VF>

The media is shown correctly in ifconfig:

ixv0: flags=0x8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
         capabilities=0x7ff80<TSO4,IP4CSUM_Rx,IP4CSUM_Tx,TCP4CSUM_Rx>
         capabilities=0x7ff80<TCP4CSUM_Tx,UDP4CSUM_Rx,UDP4CSUM_Tx,TCP6CSUM_Rx>
         capabilities=0x7ff80<TCP6CSUM_Tx,UDP6CSUM_Rx,UDP6CSUM_Tx,TSO6>
         enabled=0
         ec_capabilities=0xf<VLAN_MTU,VLAN_HWTAGGING,JUMBO_MTU,VLAN_HWFILTER>
         ec_enabled=0xf<VLAN_MTU,VLAN_HWTAGGING,JUMBO_MTU,VLAN_HWFILTER>
         address: f2:3b:a7:ff:fe:8f
         media: Ethernet autoselect (1000baseT full-duplex)
         status: active
         inet6 fe80::f03b:a7ff:feff:fe8f%ixv0/64 flags 0 scopeid 0x1

FreeBSD and OpenBSD work just fine.

-- 
Stephen