InfiniBand: Mellanox Technologies MT25204 [InfiniHost III Lx HCA] vs RHEL8

I have successfully used the Infiniband cards in the title for years with RHEL 6 and 7. Now with RHEL 8, they don't seem to be supported. I don't see a deprecation warning in the release notes. Is anyone successfully using these cards in RHEL 8?

I'm following the steps at https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/8/html-single/configuring_infiniband_and_rdma_networks/index but when I get to the steps on setting up an interface, it failes.

rxe_cfg add enp7s0
sh: line 0: echo: write error: Invalid argument

[root@armitage ~]# rxe_cfg start
sh: line 0: echo: write error: Invalid argument
sh: line 0: echo: write error: Invalid argument
Name Link Driver Speed NMTU IPv4_addr RDEV RMTU
br0 yes bridge 1500 172.31.100.17
enp3s0f0 yes bnx2 1500
enp3s0f1 no bnx2 1500
enp4s0f0 no bnx2 1500
enp4s0f1 yes bnx2 1500
virbr0 no bridge 1500 192.168.122.1
virbr0-nic no tun 1500
vnet0 yes tun 1500

I also tried mstconfig -d 0e:00.0 q and I get errors:

mstconfig -d 0e:00.0 q
-E- Failed to open the device

This definitely worked yesterday when I had RHEL 7 installed on this exact hardware. What am I missing?