Chelsio / cxlv(4): strange messages, SR-IOV interface does not work

hello,

i'm trying to configure a cxlv(4) device, which is a VF of a Chelsio 
T540-CR on a host running bhyve.

host: FreeBSD 15.0-CURRENT #3 lf/main-n269068-2cff93ced1d: Wed Oct 23 
02:48:20 BST 2024
guest: FreeBSD 15.0-CURRENT #2 lf/main-n269067-56dd459904b: Sat Oct 19 
18:36:40 BST 2024

the VF appears correctly in the VM:

root@lily:~ # kldload if_cxlv
t5vf0: <Chelsio T540-CR VF> mem 
0xc000e000-0xc000efff,0xc0000000-0xc0007fff,0xc0008000-0xc0009fff at 
device 6.0 on pci0
t5vf0: 1 ports, 2 MSI-X interrupts, 4 eq, 2 iq
cxlv0: <port 0> on t5vf0
cxlv0: 2 txq, 1 rxq (NIC)

and after bringing the interface 'up' everything seems fine:

root@lily:~ # ifconfig cxlv0
cxlv0: flags=1008843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST,LOWER_UP> 
metric 0 mtu 1500
  
options=6ec07bb<RXCSUM,TXCSUM,VLAN_MTU,VLAN_HWTAGGING,JUMBO_MTU,VLAN_HWCSUM,TSO4,TSO6,LRO,VLAN_HWTSO,LINKSTATE,RXCSUM_IPV6,TXCSUM_IPV6,HWSTATS,HWRXTSTMP,MEXTPG>
         ether 06:44:3f:e7:60:30
         media: Ethernet 10Gbase-Twinax <full-duplex> (10Gbase-Twinax 
<full-duplex,rxpause,txpause>)
         status: active
         nd6 options=29<PERFORMNUD,IFDISABLED,AUTO_LINKLOCAL>

however, trying to assign an IP address causes immediate problems:

root@lily:~ # ifconfig cxlv0 inet6 2001:8b0:aab5:7::10/64
root@lily:~ # Oct 23 06:16:07 lily kernel: cxlv0: a looped back NS 
message is detected during DAD for fe80:3::444:3fff:fee7:6030.  Another 
DAD probes are being sent.
root@lily:~ # dmesg|grep loop
cxlv0: a looped back NS message is detected during DAD for 
fe80:3::444:3fff:fee7:6030.  Another DAD probes are being sent.
cxlv0: a looped back NS message is detected during DAD for 
fe80:3::444:3fff:fee7:6030.  Another DAD probes are being sent.
cxlv0: a looped back NS message is detected during DAD for 
fe80:3::444:3fff:fee7:6030.  Another DAD probes are being sent.
cxlv0: a looped back NS message is detected during DAD for 
fe80:3::444:3fff:fee7:6030.  Another DAD probes are being sent.
cxlv0: a looped back NS message is detected during DAD for 
fe80:3::444:3fff:fee7:6030.  Another DAD probes are being sent.
cxlv0: a looped back NS message is detected during DAD for 
fe80:3::444:3fff:fee7:6030.  Another DAD probes are being sent.
cxlv0: a looped back NS message is detected during DAD for 
fe80:3::444:3fff:fee7:6030.  Another DAD probes are being sent.

i find this strange because the link local IP address in the kernel 
error is not even configured on the interface:

root@lily:~ # ifconfig cxlv0
cxlv0: flags=1008843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST,LOWER_UP> 
metric 0 mtu 1500
  
options=6ec07bb<RXCSUM,TXCSUM,VLAN_MTU,VLAN_HWTAGGING,JUMBO_MTU,VLAN_HWCSUM,TSO4,TSO6,LRO,VLAN_HWTSO,LINKSTATE,RXCSUM_IPV6,TXCSUM_IPV6,HWSTATS,HWRXTSTMP,MEXTPG>
         ether 06:44:3f:e7:60:30
         inet6 2001:8b0:aab5:7::10/64
         inet6 fe80::444:3fff:fee7:6030%cxlv0/64 tentative scopeid 0x3
         media: Ethernet 10Gbase-Twinax <full-duplex> (10Gbase-Twinax 
<full-duplex,rxpause,txpause>)
         status: active
         nd6 options=21<PERFORMNUD,AUTO_LINKLOCAL>

am i doing something wrong here?

	thanks, lexi.