rte_flow: total_length field match not working (MLX5)?

[Tony Hart]

I'm trying to match on the IPv4 total-length field using the feature
introduced in DPDK 23.07; however although the length option is
accepted by testpmd it seems that it's ignored by Connectx6.

I'm sending small packets. e.g.

09:44:39.617427 IP 100.100.1.14.10000 > 1.1.1.1.80: Flags [S], seq
408572454:408572460, win 8192, length 6: HTTP

and have the following flows set in testpmd...

flow create 0 ingress pattern end actions jump group 1 / end
flow create 0 group 1 ingress pattern eth / ipv4 dst is 1.1.1.1 length
spec 1400 length last 1448 / end actions count / drop / end

However the flow is matched even though the packet should fail the
length criteria.

testpmd> flow list 0
ID    Group    Prio    Attr    Rule
0    0    0    i--    => JUMP
1    1    0    i--    ETH IPV4 => COUNT DROP

testpmd> flow query 0 1 count
COUNT:
 hits_set: 1
 bytes_set: 1
 hits: 13
 bytes: 832

Any thoughts?
Tony

btw, I'm using OFED 5.8 and firmware version 22.35.2000

mlnx-ofa_kernel-5.8-OFED.5.8.1.1.2.1.rhel9u1.x86_64
kmod-mlnx-ofa_kernel-5.8-OFED.5.8.1.1.2.1.rhel9u1.x86_64
mlnx-ofa_kernel-devel-5.8-OFED.5.8.1.1.2.1.rhel9u1.x86_64
ofed-scripts-5.8-OFED.5.8.1.1.2.x86_64

hca_id:    mlx5_0
    transport:            InfiniBand (0)
    fw_ver:                22.35.2000
    node_guid:            e8eb:d303:00b4:7c86
    sys_image_guid:            e8eb:d303:00b4:7c86
    vendor_id:            0x02c9
    vendor_part_id:            4125
    hw_ver:                0x0
    board_id:            MT_0000000359