zdev provides dracut logic for configuring devices early during boot via
kernel command line parameters rd.dasd and rd.zfcp. A copy of resulting
configuration directives is made available to the booted Linux using
chzdev's export function.
The use of command line option --all in this export step results in
chzdev loading all kernel modules required by supported types, even if
no device of that type exists on the booted system, or if no zdev kernel
parameter was specified.
Loading unused kernel modules during boot increases memory usage,
prolongs boot time, and expands the kernel's attack surface
unnecessarily.
Fix this by replacing command line option --all with --configured to
instruct chzdev to export only data for devices with a persistent
configuration, while not loading any kernel modules.
Reviewed-by: Jan Höppner <hoeppner@linux.ibm.com>
Reviewed-by: Vineeth Vijayan <vneethv@linux.ibm.com>
Signed-off-by: Peter Oberparleiter <oberpar@linux.ibm.com>
Signed-off-by: Jan Höppner <hoeppner@linux.ibm.com>
Useful for debugging (what happened during early boot).
Also useful for distro installers, which can import the early config into
their own environment early after starting:
chzdev --import /run/zdev.initrd.config --persistent --yes \
--no-root-update --force --verbose
After that, distro installers can modify/add the device config based
on interactive or unattended installation choices using
chzdev --enable --active --persistent ...
Finally, distro installers can likewise transfer the entire device config
to the installed system mounted under $SYSROOT:
chzdev --export /tmp/zdev.config --all --type --persistent --verbose
Github-ID: https://github.com/ibm-s390-linux/s390-tools/pull/158
Acked-by: Vineeth Vijayan <vneethv@linux.ibm.com>
Acked-by: Peter Oberparleiter <oberpar@linux.ibm.com>
Signed-off-by: Steffen Maier <maier@linux.ibm.com>
Signed-off-by: Jan Höppner <hoeppner@linux.ibm.com>
