obs-packaging: support kernel fragments

use `merge_config.sh` script to generate the final `.config` file if the
`${arch}_kata_kvm_*` file doesn't exist.

Signed-off-by: Julio Montes <julio.montes@intel.com>

obs-packaging/linux-container/debian.rules

@@ -17,7 +17,15 @@ override_dh_auto_build:
 	tar xzf /usr/src/packages/SOURCES/$(KERNEL_CONFIGS).tar.gz
 	rm -f .config
 	find $(KERNEL_CONFIGS) -name "$(KERNEL_ARCH)_kata_kvm_*" -exec cp {} .config \;
+	if [ ! -f .config ]; then
+		# Use fragments to generate the .config
+		frag_dir="kata-kernel-configs/fragments"
+		err_msg="not in final"
+		r="$(KCONFIG_CONFIG=.config ARCH=${kernelArch} scripts/kconfig/merge_config.sh -r -n ${frag_dir}/common/* ${frag_dir}/${kernelArch}/* | grep "${err_msg}")" || true
+		[ -z "${r}" ] || (@echo "ERROR: ${r}"; exit 1)
+	fi
 	[ -f .config ] || (@echo "ERROR: cannot find the kernel config file for the $(KERNEL_ARCH) architecture"; exit 1)
+
 	# https://github.com/kata-containers/packaging/issues/394 enable reproducible builds:
 	export KBUILD_BUILD_USER=katabuilduser
 	export KBUILD_BUILD_HOST=katabuildhost

obs-packaging/linux-container/kata-linux-container.spec-template

@@ -80,7 +80,14 @@ BuildKernel() {
     # Runtime .config selection based on kernelArch
     rm -f .config
     find kata-kernel-configs -name "${kernelArch}_kata_kvm_*" -exec cp {} .config \;
-	[ -f .config ] || (echo "ERROR: cannot find the kernel config file for the ${kernelArch} architecture"; exit 1)
+    if [ ! -f .config ]; then
+        # Use fragments to generate the .config
+        frag_dir="kata-kernel-configs/fragments"
+        err_msg="not in final"
+        r="$(KCONFIG_CONFIG=.config ARCH=${kernelArch} scripts/kconfig/merge_config.sh -r -n ${frag_dir}/common/* ${frag_dir}/${kernelArch}/* | grep "${err_msg}")" || true
+        [ -z "${r}" ] || (echo "ERROR: ${r}"; exit 1)
+    fi
+    [ -f .config ] || (echo "ERROR: cannot find the kernel config file for the ${kernelArch} architecture"; exit 1)
 
     %if 0%{?rhel_version} || 0%{?suse_version}
     # RHEL in OBS has updated gcc.

obs-packaging/linux-container/update.sh

@@ -50,10 +50,10 @@ RELEASE=$(get_obs_pkg_release "${PROJECT_REPO}")
 
 kernel_sha256=$(curl -L -s -f ${KR_SHA} | awk '/linux-'${VERSION}'.tar.xz/ {print $1}')
 
-# Copy the kernel config files for all architecture
+# Copy the kernel config files and fragments for all architecture
 mkdir -p configs
 readonly configs_dir="kernel/configs"
-find "${SCRIPT_DIR}/../../${configs_dir}" -name "*_kata_kvm_${KR_LTS}.x" -exec tar --transform="s,${configs_dir},${KR_CONFIGS}," -czf ${KR_CONFIGS}.tar.gz {} +
+find "${SCRIPT_DIR}/../../${configs_dir}" \( -name "*_kata_kvm_${KR_LTS}.x" -o -name fragments \) -exec tar --transform="s,${configs_dir},${KR_CONFIGS}," -czf ${KR_CONFIGS}.tar.gz {} +
 
 replace_list=(
 	"VERSION=${VERSION}"