github: add guest OS selection for CI testing

Add manual guest OS selection to GitHub Actions workflows, allowing
testing of distribution-specific fixes across Debian and Fedora
guests. The workflow_dispatch trigger accepts 'default', 'debian-13',
or 'fedora-41', merging the corresponding guestfs config fragment to
override the defconfig's guest OS choice.

This enables validation of cross-distribution compatibility for fixes
like the locale and SELinux changes in this series.

Link: https://lore.kernel.org/kdevops/[email protected]/
Generated-by: Claude AI
Signed-off-by: Daniel Gomez <[email protected]>

Author: dkruces

.github/actions/configure/action.yml

@@ -20,6 +20,10 @@ inputs:
     required: false
     type: string
     default: 'kdevops-ci'
+  guest_os:
+    required: false
+    type: string
+    default: 'default'
 
 runs:
   using: "composite"
@@ -112,11 +116,27 @@ runs:
           echo "Using Linux CI configuration (4GB/8core VMs)"
         fi
 
+        # Configure guest OS if specified
+        GUEST_OS_CONFIG=
+        if [[ "${{ inputs.guest_os }}" != "default" ]]; then
+          GUEST_OS_CONFIG="defconfigs/configs/guestfs-${{ inputs.guest_os }}.config"
+
+          if [[ ! -f "$GUEST_OS_CONFIG" ]]; then
+            echo "Error: Guest OS config not found: $GUEST_OS_CONFIG"
+            exit 1
+          fi
+
+          echo "Using guest OS configuration: $GUEST_OS_CONFIG"
+        else
+          echo "Using default guest OS from defconfig"
+        fi
+
         ./scripts/kconfig/merge_config.sh \
         -n .config \
         defconfigs/configs/diy.config \
         defconfigs/configs/ci.config \
-        ${VM_CONFIG_ARG}
+        ${VM_CONFIG_ARG} \
+        ${GUEST_OS_CONFIG}
 
     - name: Run kdevops make
       shell: bash

.github/workflows/kdevops.yml

@@ -88,6 +88,15 @@ on:
         options:
           - 'kdevops-ci'
           - 'linux-ci'
+      guest_os:
+        description: 'Guest OS for testing'
+        required: false
+        default: 'default'
+        type: choice
+        options:
+          - default      # Use defconfig's default (typically Debian 13 on debian hosts)
+          - debian-13    # Force Debian 13 Trixie
+          - fedora-41    # Force Fedora 41
       tests:
         description: 'Custom test to run (for kdevops-ci mode only)'
         required: false
@@ -231,6 +240,7 @@ jobs:
         uses: ./.github/actions/configure
         with:
           ci_workflow: ${{ matrix.ci_workflow }}
+          guest_os: ${{ github.event.inputs.guest_os || 'default' }}
           kernel_ref: >-
             ${{
               github.event_name == 'schedule' && needs.generate_kernel_ref.outputs.kernel_ref