[PATCH 0/3] Add configuration fragment support to kdevops

[PATCH 0/3] Add configuration fragment support to kdevops

[Daniel Gomez]

This series introduces Linux kernel-style configuration fragment support
to kdevops, enabling flexible configuration composition and better
maintainability.

* Import merge_config.sh from Linux kernel for fragment merging
* Update scripts/config with latest upstream fixes (v5.11 -> v6.15)
* Add practical VM configuration fragments for guest scaling

Benefits:
- Modular configuration: Compose complex configs from reusable fragments
- Better maintainability: Separate concerns (VM sizing, features, workflows)
- Flexible deployment: Mix and match fragments for different scenarios
- Upstream compatibility: Uses standard Linux kernel tooling

Usage example:

* Minimal development VM + diy enablement:
make dynamic_pcipassthrough_kconfig KDEVOPS_ENABLE_PCIE_KCONFIG=1
make defconfig-sysbench-mysql-atomic-tps-variability
./scripts/kconfig/merge_config.sh -n .config \
    ./defconfigs/configs/vm2g2c.config
    ./defconfigs/configs/diy.config \

This builds on the kconfig environment discussion [1] and provides an
alternative to the SAT solver solution.

Link: https://lore.kernel.org/kdevops/20250704-b4-params-v1-1-42dd4ff478b3@samsung.com/ [1]

Signed-off-by: Daniel Gomez <da.gomez@samsung.com>
---
Daniel Gomez (3):
      scripts: add merge_confg.sh support
      defconfig: add VM memory and cpu scaling fragments
      scripts/config: update f5ef2f7bf2e3 -> d5bfb6b3814b

 defconfigs/configs/diy.config     |   3 +
 defconfigs/configs/vm2g2c.config  |   2 +
 defconfigs/configs/vm32g8c.config |   2 +
 scripts/config                    |  26 +++--
 scripts/kconfig/merge_config.sh   | 213 ++++++++++++++++++++++++++++++++++++++
 5 files changed, 236 insertions(+), 10 deletions(-)
---
base-commit: 685cf3e15b6b22492aa8e9ad7774b1e84b992325
change-id: 20250917-kdevops-fragment-support-6141f8979b24

Best regards,
--  
Daniel Gomez <da.gomez@samsung.com>

[PATCH 1/3] scripts: add merge_confg.sh support

[Daniel Gomez]

From: Daniel Gomez <da.gomez@samsung.com>

From vanilla linux scripts/kconfig/merge_config.sh.

./scripts/kconfig/merge_config.sh \
-n \
.config \
./defconfigs/configs/feature1.config \
./defconfigs/configs/feature2.config \
./defconfigs/configs/feature3.config

Add diy.config fragment as initial example. This fragment enables DIY
stdout callback support.

scripts/kconfig/merge_config.sh latest changes:
a26fe287eed1 ("kconfig: merge_config: use an empty file as initfile")
33330bcf0318 ("scripts: kconfig: merge_config: config files: add a
trailing newline")
1073c15fd39e ("scripts: merge_config: Fix typo in variable name")
46dff8d7e381 ("scripts: merge_config: Add option to suppress warning
on overrides")
a325db2d8f1d ("scripts: merge_config: add strict mode to fail upon any
redefinition")

Signed-off-by: Daniel Gomez <da.gomez@samsung.com>
---
 defconfigs/configs/diy.config   |   3 +
 scripts/kconfig/merge_config.sh | 213 ++++++++++++++++++++++++++++++++++++++++
 2 files changed, 216 insertions(+)

diff --git a/defconfigs/configs/diy.config b/defconfigs/configs/diy.config
new file mode 100644
index 00000000..ba95c3db
--- /dev/null
+++ b/defconfigs/configs/diy.config
@@ -0,0 +1,3 @@
+CONFIG_ANSIBLE_CFG_CALLBACK_PLUGIN_DIY=y
+CONFIG_ANSIBLE_CFG_CALLBACK_PLUGIN_DISPLAY_OK_HOSTS=n
+CONFIG_ANSIBLE_CFG_CALLBACK_PLUGIN_DISPLAY_FAILED_STDERR=y
diff --git a/scripts/kconfig/merge_config.sh b/scripts/kconfig/merge_config.sh
new file mode 100755
index 00000000..79c09b37
--- /dev/null
+++ b/scripts/kconfig/merge_config.sh
@@ -0,0 +1,213 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+#
+#  merge_config.sh - Takes a list of config fragment values, and merges
+#  them one by one. Provides warnings on overridden values, and specified
+#  values that did not make it to the resulting .config file (due to missed
+#  dependencies or config symbol removal).
+#
+#  Portions reused from kconf_check and generate_cfg:
+#  http://git.yoctoproject.org/cgit/cgit.cgi/yocto-kernel-tools/tree/tools/kconf_check
+#  http://git.yoctoproject.org/cgit/cgit.cgi/yocto-kernel-tools/tree/tools/generate_cfg
+#
+#  Copyright (c) 2009-2010 Wind River Systems, Inc.
+#  Copyright 2011 Linaro
+
+set -e
+
+clean_up() {
+	rm -f $TMP_FILE
+	rm -f $MERGE_FILE
+}
+
+usage() {
+	echo "Usage: $0 [OPTIONS] [CONFIG [...]]"
+	echo "  -h    display this help text"
+	echo "  -m    only merge the fragments, do not execute the make command"
+	echo "  -n    use allnoconfig instead of alldefconfig"
+	echo "  -r    list redundant entries when merging fragments"
+	echo "  -y    make builtin have precedence over modules"
+	echo "  -O    dir to put generated output files.  Consider setting \$KCONFIG_CONFIG instead."
+	echo "  -s    strict mode. Fail if the fragment redefines any value."
+	echo "  -Q    disable warning messages for overridden options."
+	echo
+	echo "Used prefix: '$CONFIG_PREFIX'. You can redefine it with \$CONFIG_ environment variable."
+}
+
+RUNMAKE=true
+ALLTARGET=alldefconfig
+WARNREDUN=false
+BUILTIN=false
+OUTPUT=.
+STRICT=false
+CONFIG_PREFIX=${CONFIG_-CONFIG_}
+WARNOVERRIDE=echo
+
+while true; do
+	case $1 in
+	"-n")
+		ALLTARGET=allnoconfig
+		shift
+		continue
+		;;
+	"-m")
+		RUNMAKE=false
+		shift
+		continue
+		;;
+	"-h")
+		usage
+		exit
+		;;
+	"-r")
+		WARNREDUN=true
+		shift
+		continue
+		;;
+	"-y")
+		BUILTIN=true
+		shift
+		continue
+		;;
+	"-O")
+		if [ -d $2 ];then
+			OUTPUT=$(echo $2 | sed 's/\/*$//')
+		else
+			echo "output directory $2 does not exist" 1>&2
+			exit 1
+		fi
+		shift 2
+		continue
+		;;
+	"-s")
+		STRICT=true
+		shift
+		continue
+		;;
+	"-Q")
+		WARNOVERRIDE=true
+		shift
+		continue
+		;;
+	*)
+		break
+		;;
+	esac
+done
+
+if [ "$#" -lt 1 ] ; then
+	usage
+	exit
+fi
+
+if [ -z "$KCONFIG_CONFIG" ]; then
+	if [ "$OUTPUT" != . ]; then
+		KCONFIG_CONFIG=$(readlink -m -- "$OUTPUT/.config")
+	else
+		KCONFIG_CONFIG=.config
+	fi
+fi
+
+INITFILE=$1
+shift;
+
+if [ ! -r "$INITFILE" ]; then
+	echo "The base file '$INITFILE' does not exist. Creating one..." >&2
+	touch "$INITFILE"
+fi
+
+MERGE_LIST=$*
+SED_CONFIG_EXP1="s/^\(${CONFIG_PREFIX}[a-zA-Z0-9_]*\)=.*/\1/p"
+SED_CONFIG_EXP2="s/^# \(${CONFIG_PREFIX}[a-zA-Z0-9_]*\) is not set$/\1/p"
+
+TMP_FILE=$(mktemp ./.tmp.config.XXXXXXXXXX)
+MERGE_FILE=$(mktemp ./.merge_tmp.config.XXXXXXXXXX)
+
+echo "Using $INITFILE as base"
+
+trap clean_up EXIT
+
+cat $INITFILE > $TMP_FILE
+
+# Merge files, printing warnings on overridden values
+for ORIG_MERGE_FILE in $MERGE_LIST ; do
+	echo "Merging $ORIG_MERGE_FILE"
+	if [ ! -r "$ORIG_MERGE_FILE" ]; then
+		echo "The merge file '$ORIG_MERGE_FILE' does not exist.  Exit." >&2
+		exit 1
+	fi
+	cat $ORIG_MERGE_FILE > $MERGE_FILE
+	CFG_LIST=$(sed -n -e "$SED_CONFIG_EXP1" -e "$SED_CONFIG_EXP2" $MERGE_FILE)
+
+	for CFG in $CFG_LIST ; do
+		grep -q -w $CFG $TMP_FILE || continue
+		PREV_VAL=$(grep -w $CFG $TMP_FILE)
+		NEW_VAL=$(grep -w $CFG $MERGE_FILE)
+		BUILTIN_FLAG=false
+		if [ "$BUILTIN" = "true" ] && [ "${NEW_VAL#CONFIG_*=}" = "m" ] && [ "${PREV_VAL#CONFIG_*=}" = "y" ]; then
+			${WARNOVERRIDE} Previous  value: $PREV_VAL
+			${WARNOVERRIDE} New value:       $NEW_VAL
+			${WARNOVERRIDE} -y passed, will not demote y to m
+			${WARNOVERRIDE}
+			BUILTIN_FLAG=true
+		elif [ "x$PREV_VAL" != "x$NEW_VAL" ] ; then
+			${WARNOVERRIDE} Value of $CFG is redefined by fragment $ORIG_MERGE_FILE:
+			${WARNOVERRIDE} Previous  value: $PREV_VAL
+			${WARNOVERRIDE} New value:       $NEW_VAL
+			${WARNOVERRIDE}
+			if [ "$STRICT" = "true" ]; then
+				STRICT_MODE_VIOLATED=true
+			fi
+		elif [ "$WARNREDUN" = "true" ]; then
+			${WARNOVERRIDE} Value of $CFG is redundant by fragment $ORIG_MERGE_FILE:
+		fi
+		if [ "$BUILTIN_FLAG" = "false" ]; then
+			sed -i "/$CFG[ =]/d" $TMP_FILE
+		else
+			sed -i "/$CFG[ =]/d" $MERGE_FILE
+		fi
+	done
+	# In case the previous file lacks a new line at the end
+	echo >> $TMP_FILE
+	cat $MERGE_FILE >> $TMP_FILE
+done
+
+if [ "$STRICT_MODE_VIOLATED" = "true" ]; then
+	echo "The fragment redefined a value and strict mode had been passed."
+	exit 1
+fi
+
+if [ "$RUNMAKE" = "false" ]; then
+	cp -T -- "$TMP_FILE" "$KCONFIG_CONFIG"
+	echo "#"
+	echo "# merged configuration written to $KCONFIG_CONFIG (needs make)"
+	echo "#"
+	exit
+fi
+
+# If we have an output dir, setup the O= argument, otherwise leave
+# it blank, since O=. will create an unnecessary ./source softlink
+OUTPUT_ARG=""
+if [ "$OUTPUT" != "." ] ; then
+	OUTPUT_ARG="O=$OUTPUT"
+fi
+
+
+# Use the merged file as the starting point for:
+# alldefconfig: Fills in any missing symbols with Kconfig default
+# allnoconfig: Fills in any missing symbols with # CONFIG_* is not set
+make KCONFIG_ALLCONFIG=$TMP_FILE $OUTPUT_ARG $ALLTARGET
+
+
+# Check all specified config values took (might have missed-dependency issues)
+for CFG in $(sed -n -e "$SED_CONFIG_EXP1" -e "$SED_CONFIG_EXP2" $TMP_FILE); do
+
+	REQUESTED_VAL=$(grep -w -e "$CFG" $TMP_FILE)
+	ACTUAL_VAL=$(grep -w -e "$CFG" "$KCONFIG_CONFIG" || true)
+	if [ "x$REQUESTED_VAL" != "x$ACTUAL_VAL" ] ; then
+		echo "Value requested for $CFG not in final .config"
+		echo "Requested value:  $REQUESTED_VAL"
+		echo "Actual value:     $ACTUAL_VAL"
+		echo ""
+	fi
+done

-- 
2.50.1

[PATCH 2/3] defconfig: add VM memory and cpu scaling fragments

[Daniel Gomez]

From: Daniel Gomez <da.gomez@samsung.com>

Add vm configuration fragments support:
* vm2g2c: 2GB RAM, 2 CPU cores
* vm32g8c: 32GB RAM, 8 CPU cores

Note that we use 4GB/8c by default.

Signed-off-by: Daniel Gomez <da.gomez@samsung.com>
---
 defconfigs/configs/vm2g2c.config  | 2 ++
 defconfigs/configs/vm32g8c.config | 2 ++
 2 files changed, 4 insertions(+)

diff --git a/defconfigs/configs/vm2g2c.config b/defconfigs/configs/vm2g2c.config
new file mode 100644
index 00000000..af9edee5
--- /dev/null
+++ b/defconfigs/configs/vm2g2c.config
@@ -0,0 +1,2 @@
+CONFIG_LIBVIRT_VCPUS_2=y
+CONFIG_LIBVIRT_MEM_2G=y
diff --git a/defconfigs/configs/vm32g8c.config b/defconfigs/configs/vm32g8c.config
new file mode 100644
index 00000000..06a5ca44
--- /dev/null
+++ b/defconfigs/configs/vm32g8c.config
@@ -0,0 +1,2 @@
+CONFIG_LIBVIRT_VCPUS_8=y
+CONFIG_LIBVIRT_MEM_32G=y

-- 
2.50.1

[PATCH 3/3] scripts/config: update f5ef2f7bf2e3 -> d5bfb6b3814b

[Daniel Gomez]

From: Daniel Gomez <da.gomez@samsung.com>

Changes:
f757f6011c92 kbuild: fix argument parsing in scripts/config

Note: v5.11 -> v6.15

Signed-off-by: Daniel Gomez <da.gomez@samsung.com>
---
 scripts/config | 26 ++++++++++++++++----------
 1 file changed, 16 insertions(+), 10 deletions(-)

diff --git a/scripts/config b/scripts/config
index ff88e2fa..ea475c07 100755
--- a/scripts/config
+++ b/scripts/config
@@ -32,6 +32,7 @@ commands:
                              Disable option directly after other option
 	--module-after|-M beforeopt option
                              Turn option into module directly after other option
+	--refresh            Refresh the config using old settings
 
 	commands can be repeated multiple times
 
@@ -124,16 +125,22 @@ undef_var() {
 	txt_delete "^# $name is not set" "$FN"
 }
 
-if [ "$1" = "--file" ]; then
-	FN="$2"
-	if [ "$FN" = "" ] ; then
-		usage
+FN=.config
+CMDS=()
+while [[ $# -gt 0 ]]; do
+	if [ "$1" = "--file" ]; then
+		if [ "$2" = "" ]; then
+			usage
+		fi
+		FN="$2"
+		shift 2
+	else
+		CMDS+=("$1")
+		shift
 	fi
-	shift 2
-else
-	FN=.config
-fi
+done
 
+set -- "${CMDS[@]}"
 if [ "$1" = "" ] ; then
 	usage
 fi
@@ -217,9 +224,8 @@ while [ "$1" != "" ] ; do
 		set_var "${CONFIG_}$B" "${CONFIG_}$B=m" "${CONFIG_}$A"
 		;;
 
-	# undocumented because it ignores --file (fixme)
 	--refresh)
-		yes "" | make oldconfig
+		yes "" | make oldconfig KCONFIG_CONFIG=$FN
 		;;
 
 	*)

-- 
2.50.1

Re: [PATCH 0/3] Add configuration fragment support to kdevops

[Luis Chamberlain]

On Wed, Sep 17, 2025 at 02:29:17PM +0200, Daniel Gomez wrote:
> This series introduces Linux kernel-style configuration fragment support
> to kdevops, enabling flexible configuration composition and better
> maintainability.
> 
> * Import merge_config.sh from Linux kernel for fragment merging
> * Update scripts/config with latest upstream fixes (v5.11 -> v6.15)
> * Add practical VM configuration fragments for guest scaling
> 
> Benefits:
> - Modular configuration: Compose complex configs from reusable fragments
> - Better maintainability: Separate concerns (VM sizing, features, workflows)
> - Flexible deployment: Mix and match fragments for different scenarios
> - Upstream compatibility: Uses standard Linux kernel tooling
> 
> Usage example:
> 
> * Minimal development VM + diy enablement:
> make dynamic_pcipassthrough_kconfig KDEVOPS_ENABLE_PCIE_KCONFIG=1
> make defconfig-sysbench-mysql-atomic-tps-variability
> ./scripts/kconfig/merge_config.sh -n .config \
>     ./defconfigs/configs/vm2g2c.config
>     ./defconfigs/configs/diy.config \
> 
> This builds on the kconfig environment discussion [1] and provides an
> alternative to the SAT solver solution.
> 
> Link: https://lore.kernel.org/kdevops/20250704-b4-params-v1-1-42dd4ff478b3@samsung.com/ [1]
> 
> Signed-off-by: Daniel Gomez <da.gomez@samsung.com>

Thanks, applied and pushed!

  Luis

Re: [PATCH 0/3] Add configuration fragment support to kdevops

[Luis Chamberlain]

On Wed, Sep 17, 2025 at 02:29:17PM +0200, Daniel Gomez wrote:
> This series introduces Linux kernel-style configuration fragment support
> to kdevops, enabling flexible configuration composition and better
> maintainability.
> 
> * Import merge_config.sh from Linux kernel for fragment merging
> * Update scripts/config with latest upstream fixes (v5.11 -> v6.15)
> * Add practical VM configuration fragments for guest scaling
> 
> Benefits:
> - Modular configuration: Compose complex configs from reusable fragments
> - Better maintainability: Separate concerns (VM sizing, features, workflows)
> - Flexible deployment: Mix and match fragments for different scenarios
> - Upstream compatibility: Uses standard Linux kernel tooling
> 
> Usage example:
> 
> * Minimal development VM + diy enablement:
> make dynamic_pcipassthrough_kconfig KDEVOPS_ENABLE_PCIE_KCONFIG=1
> make defconfig-sysbench-mysql-atomic-tps-variability
> ./scripts/kconfig/merge_config.sh -n .config \
>     ./defconfigs/configs/vm2g2c.config
>     ./defconfigs/configs/diy.config \
> 
> This builds on the kconfig environment discussion [1] and provides an
> alternative to the SAT solver solution.
> 
> Link: https://lore.kernel.org/kdevops/20250704-b4-params-v1-1-42dd4ff478b3@samsung.com/ [1]
> 
> Signed-off-by: Daniel Gomez <da.gomez@samsung.com>

This is nice, but does it scale? I don't think so. So my ask would be to
see if you can integrate the pico SAT patches to our shared kconfig tree
tree first under a new branch which branches out of the origin/yamlconfig
branch. Then merge that to kdevops and evaluate what a true SAT solver
can do. This let's us essentially lead the way forward for Linux.

The experiences we learn can be brought back to Linux.

  Luis

Re: [PATCH 0/3] Add configuration fragment support to kdevops

[Daniel Gomez]

On 18/09/2025 23.19, Luis Chamberlain wrote:
> On Wed, Sep 17, 2025 at 02:29:17PM +0200, Daniel Gomez wrote:
>> This series introduces Linux kernel-style configuration fragment support
>> to kdevops, enabling flexible configuration composition and better
>> maintainability.
>>
>> * Import merge_config.sh from Linux kernel for fragment merging
>> * Update scripts/config with latest upstream fixes (v5.11 -> v6.15)
>> * Add practical VM configuration fragments for guest scaling
>>
>> Benefits:
>> - Modular configuration: Compose complex configs from reusable fragments
>> - Better maintainability: Separate concerns (VM sizing, features, workflows)
>> - Flexible deployment: Mix and match fragments for different scenarios
>> - Upstream compatibility: Uses standard Linux kernel tooling
>>
>> Usage example:
>>
>> * Minimal development VM + diy enablement:
>> make dynamic_pcipassthrough_kconfig KDEVOPS_ENABLE_PCIE_KCONFIG=1
>> make defconfig-sysbench-mysql-atomic-tps-variability
>> ./scripts/kconfig/merge_config.sh -n .config \
>>     ./defconfigs/configs/vm2g2c.config
>>     ./defconfigs/configs/diy.config \
>>
>> This builds on the kconfig environment discussion [1] and provides an
>> alternative to the SAT solver solution.
>>
>> Link: https://lore.kernel.org/kdevops/20250704-b4-params-v1-1-42dd4ff478b3@samsung.com/ [1]
>>
>> Signed-off-by: Daniel Gomez <da.gomez@samsung.com>
> 
> This is nice, but does it scale? I don't think so.

100%. That said, there isn't much difference between our defconfigs/* and
fragments. A fragment is simply a reusable piece of configuration that we
repeat across all defconfigs. For example, this allows users to combine xfs
defconfigs + vm configuration. 


> So my ask would be to
> see if you can integrate the pico SAT patches to our shared kconfig tree
> tree first under a new branch which branches out of the origin/yamlconfig
> branch. Then merge that to kdevops and evaluate what a true SAT solver
> can do. This let's us essentially lead the way forward for Linux.


I already have higher priority tasks on my plate right now (CI). Let's make a plan instead. 
I believe Chuck was putting together a task list for terraform. Would it help to have
a global backlog for tasks to do? 

> 
> The experiences we learn can be brought back to Linux.
> 
>   Luis

Re: [PATCH 0/3] Add configuration fragment support to kdevops

[Luis Chamberlain]

On Fri, Sep 19, 2025 at 10:41:53AM +0200, Daniel Gomez wrote:
> On 18/09/2025 23.19, Luis Chamberlain wrote:
> > On Wed, Sep 17, 2025 at 02:29:17PM +0200, Daniel Gomez wrote:
> >> This series introduces Linux kernel-style configuration fragment support
> >> to kdevops, enabling flexible configuration composition and better
> >> maintainability.
> >>
> >> * Import merge_config.sh from Linux kernel for fragment merging
> >> * Update scripts/config with latest upstream fixes (v5.11 -> v6.15)
> >> * Add practical VM configuration fragments for guest scaling
> >>
> >> Benefits:
> >> - Modular configuration: Compose complex configs from reusable fragments
> >> - Better maintainability: Separate concerns (VM sizing, features, workflows)
> >> - Flexible deployment: Mix and match fragments for different scenarios
> >> - Upstream compatibility: Uses standard Linux kernel tooling
> >>
> >> Usage example:
> >>
> >> * Minimal development VM + diy enablement:
> >> make dynamic_pcipassthrough_kconfig KDEVOPS_ENABLE_PCIE_KCONFIG=1
> >> make defconfig-sysbench-mysql-atomic-tps-variability
> >> ./scripts/kconfig/merge_config.sh -n .config \
> >>     ./defconfigs/configs/vm2g2c.config
> >>     ./defconfigs/configs/diy.config \
> >>
> >> This builds on the kconfig environment discussion [1] and provides an
> >> alternative to the SAT solver solution.
> >>
> >> Link: https://lore.kernel.org/kdevops/20250704-b4-params-v1-1-42dd4ff478b3@samsung.com/ [1]
> >>
> >> Signed-off-by: Daniel Gomez <da.gomez@samsung.com>
> > 
> > This is nice, but does it scale? I don't think so.
> 
> 100%. That said, there isn't much difference between our defconfigs/* and
> fragments. A fragment is simply a reusable piece of configuration that we
> repeat across all defconfigs. For example, this allows users to combine xfs
> defconfigs + vm configuration. 
> 
> 
> > So my ask would be to
> > see if you can integrate the pico SAT patches to our shared kconfig tree
> > tree first under a new branch which branches out of the origin/yamlconfig
> > branch. Then merge that to kdevops and evaluate what a true SAT solver
> > can do. This let's us essentially lead the way forward for Linux.
> 
> 
> I already have higher priority tasks on my plate right now (CI). Let's make a plan instead. 
> I believe Chuck was putting together a task list for terraform. Would it help to have
> a global backlog for tasks to do? 
> 

Fair enough, so rebase and push!

  Luid