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Description of problem:

On fresh RHEL 9 installation on s390x (KVM), the following message is logged in journal:

cpictl[761]: /lib/s390-tools/cpictl: line 112: echo: write error: Operation not supported

Version-Release number of selected component (if applicable):

s390utils-core-2.17.0-2.el9.s390x

How reproducible:

Deterministic.

Steps to Reproduce:
1. journalctl --no-hostname -l | grep '/lib/s390-tools/cpictl: line 112: echo: write error: Operation not supported'

Actual results:

Jul 25 08:47:26 cpictl[761]: /lib/s390-tools/cpictl: line 112: echo: write error: Operation not supported

Expected results:

No output.

Additional info:

That line does

cpi_commit()
{
        echo 1 > "$CPI_SET"
}

and CPI_SET is set to

readonly CPI_SET="/sys/firmware/cpi/set"

and permissions on that entry is

# ls -la /sys/firmware/cpi/set
--w-------. 1 root root 4096 Jul 25 08:47 /sys/firmware/cpi/set
# ls -lZ /sys/firmware/cpi/set
--w-------. 1 root root system_u:object_r:sysfs_t:s0 4096 Jul 25 08:47 /sys/firmware/cpi/set

Hmm, I don't think the CPI interface is supported for KVM guests. It means the start-up condition from https://github.com/ibm-s390-linux/s390-tools/blob/master/systemd/cpi.service.in#L14 is not valid any more, because the CPI sysfs interface always exists.

fixed with https://github.com/ibm-s390-linux/s390-tools/commit/b79d17d2334fdf7907e013d455cecf796a548d7d

reproduced on RHEL-9.1.0-20220721.1 with s390utils-core-2.19.0-2.el9.s390x
#  journalctl --no-hostname -l | grep '/lib/s390-tools/cpict'
Jul 26 15:34:02 cpictl[757]: /lib/s390-tools/cpictl: line 112: echo: write error: Operation not supported
This does not require a fresh installation, but can be triggered by reboot.
After upgrading to s390utils-core-2.21.0-1.el9.s390x, the problem disappeared.

No error on RHEL-9.1.0-20220721.1 with s390utils-core-2.21.0-1.el9.s390x : 
# journalctl --no-hostname -l | grep '/lib/s390-tools/cpict'

Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory (s390utils bug fix and enhancement update), and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://access.redhat.com/errata/RHEA-2022:8387