zdev: Add auto-config for PCI and crypto devices

PCI and crypto devices defined using the IBM Z Dynamic Partition Manager
(DPM) will start in an offline/unconfigured state that requires manual
intervention before the associated Linux function can be used. This
results for example in PCI networking interfaces being unavailable in a
distribution installer system.

Fix this by providing a udev rule and initial RAM-disk logic that
automatically enables PCI and crypto devices either during boot, or when
they are defined at run-time. This processing can be suppressed by
specifying the "rd.zdev=no-auto" parameter on the kernel command line.

Auto-configuration is limited to Linux running in DPM LPARs because
PCI-functions and crypto devices defined by DPM are always intended for
use by a single LPAR only.

For Linux running in classic-mode LPARs or virtual machines, leaving PCI
and crypto devices in an offline state may be useful to allow defining a
device as available to multiple systems, where only the system that
intends to make use of the device should enable it.

Signed-off-by: Peter Oberparleiter <oberpar@linux.ibm.com>
Reviewed-by: Jan Höppner <hoeppner@linux.ibm.com>
Signed-off-by: Jan Höppner <hoeppner@linux.ibm.com>

zdev/dracut/95zdev/module-setup.sh

@@ -20,7 +20,7 @@ check() {
     [ "$_arch" = "s390" -o "$_arch" = "s390x" ] || return 1
 
     # Ensure that required tools are available
-    require_binaries chzdev lszdev || return 1
+    require_binaries chzdev lszdev /lib/s390-tools/zdev_id || return 1
 
     return 0
 }
@@ -40,11 +40,14 @@ install() {
     local _tempfile
 
     # Ensure that required tools are available
-    inst_multiple chzdev lszdev vmcp
+    inst_multiple chzdev lszdev vmcp /lib/s390-tools/zdev_id
 
     # Hook to parse zdev kernel parameter
     inst_hook cmdline 95 "$moddir/parse-zdev.sh"
 
+    # Rule to automatically enable devices when running in DPM
+    inst_rules "81-dpm.rules"
+
     # Obtain early + root device configuration
     _tempfile=$(mktemp --tmpdir dracut-zdev.XXXXXX)
     chzdev --export "$_tempfile" --persistent --by-path / --quiet \

zdev/dracut/95zdev/parse-zdev.sh

@@ -1,6 +1,6 @@
 #!/bin/sh
 #
-# Copyright IBM Corp. 2017
+# Copyright IBM Corp. 2017,2021
 #
 # s390-tools is free software; you can redistribute it and/or modify
 # it under the terms of the MIT license. See LICENSE for details.
@@ -15,11 +15,14 @@
 #     where
 #
 #   no-auto:       Indicates that firmware-provided I/O configuration data
-#                  should not be applied.
+#                  should not be applied. This also affects automatic
+#                  activation of PCI and crypto devices when running in a DPM
+#                  LPAR.
 #
 
 zdev_fw_file="/sys/firmware/sclp_sd/config/data"
 zdev_base_args="--force --yes --no-root-update --no-settle --auto-conf --quiet"
+zdev_id="/lib/s390-tools/zdev_id"
 
 if [ -e "$zdev_fw_file" ] ; then
     zdev_auto=1
@@ -35,4 +38,22 @@ done
 
 if [ $zdev_auto -eq 1 ] ; then
     chzdev --import "$zdev_fw_file" $zdev_base_args
+
+    # Get information about DPM environment
+    for line in $($zdev_id) ; do
+        eval "$line"
+    done
+
+    if [ "$ZDEV_IS_DPM,$ZDEV_NEST_LEVEL,$ZDEV_HYPERVISOR_0" = "1,1,LPAR" ] ; then
+      # Manually iterate over existing PCI devices - there is a udev rule
+      # that handles this for PCI devices added at runtime but that doesn't
+      # work for PCI devices defined before boot because there is no coldplug
+      # trigger for /sys/bus/pci/slots
+      for slot in /sys/bus/pci/slots/* ; do
+        read power < "$slot/power"
+        if [ "$power" = "0" ] ; then
+            echo 1 > "$slot/power"
+        fi
+      done
+    fi
 fi