The "hvc_iucv_allow=" kernel parameter specifies a comma-separated list
of z/VM user IDs that are permitted to connect to the z/VM IUCV hypervisor
device driver.
The number of z/VM user IDs that are specified with the "hvc_iucv_allow="
kernel parameter exceeds the maximum of 500.
User response
Correct the "hvc_iucv_allow=" setting by reducing the z/VM user IDs in
the list and reboot Linux.