I applied the following patch to the nvme host driver to see what
is being passed to the kernel:


diff --git a/drivers/nvme/host/fabrics.c b/drivers/nvme/host/fabrics.c
index a5469fd9d4c3..a50693678223 100644
--- a/drivers/nvme/host/fabrics.c
+++ b/drivers/nvme/host/fabrics.c
@@ -582,6 +582,8 @@ static int nvmf_parse_options(struct nvmf_ctrl_options *opts,
                if (!*p)
                        continue;
 
+               pr_err("p = %s\n", p);
+
                token = match_token(p, opt_tokens, args);
                opts->mask |= token;
                switch (token) {

I removed the two "-1 checks" against tos and fast_io_fail and
executed this command: nvme connect -t tcp -a 10.19.242.3 -n test-nqn -s 4080

[root@aarch64-hv01-guest02 nvme-cli]# ./nvme connect -t tcp -a 10.19.242.3 -n test-nqn -s 4080 
Failed to write to /dev/nvme-fabrics: Invalid argument

dmesg:
[50822.773423] nvmet_tcp: enabling port 1 (10.19.242.2:4080)
[56087.340983] nvme_fabrics: p = nqn=test-nqn
[56087.344407] nvme_fabrics: p = transport=tcp
[56087.347633] nvme_fabrics: p = traddr=10.19.242.3
[56087.351113] nvme_fabrics: p = trsvcid=4080
[56087.354395] nvme_fabrics: p = hostnqn=nqn.2014-08.org.nvmexpress:uuid:e83aafbb-383f-46c8-b94b-2311e4cc436c
[56087.361733] nvme_fabrics: p = hostid=3eec713e-099e-421d-8c8f-f2b08ae9f96c
[56087.366844] nvme_fabrics: p = ctrl_loss_tmo=600
[56087.370266] nvme_fabrics: p = fast_io_fail_tmo=-1   <----- before my patch those 2 were filtered out
[56087.373935] nvme_fabrics: p = tos=-1			<----  by add_int_argument()
[56087.376616] nvme_fabrics: Invalid type of service -1   <--- Error, connection gets closed