[PATCH bpf-next v3 0/2] BPF selftest helper script

[PATCH bpf-next v3 0/2] BPF selftest helper script

[KP Singh]

# v2 -> v3

- Fixes to silence verbose commands
- Fixed output buffering without being teed out
- Fixed the clobbered error code of the script
- Other fixes suggested by Andrii

# v1 -> v2

- The script now compiles the kernel by default, and the -k option
  implies "keep the kernel"
- Pointer to the script in the docs.
- Some minor simplifications.

Allow developers and contributors to understand if their changes would
end up breaking the BPF CI and avoid the back and forth required for
fixing the test cases in the CI environment. The series also adds a
pointer in tools/testing/selftests/bpf/README.rst.


KP Singh (2):
  bpf: Helper script for running BPF presubmit tests
  bpf/selftests: Add a short note about run_in_vm.sh in README.rst

 tools/testing/selftests/bpf/README.rst   |  24 ++
 tools/testing/selftests/bpf/run_in_vm.sh | 356 +++++++++++++++++++++++
 2 files changed, 380 insertions(+)
 create mode 100755 tools/testing/selftests/bpf/run_in_vm.sh

-- 
2.30.0.365.g02bc693789-goog

[PATCH bpf-next v3 1/2] bpf: Helper script for running BPF presubmit tests

[KP Singh]

The script runs the BPF selftests locally on the same kernel image
as they would run post submit in the BPF continuous integration
framework.

The goal of the script is to allow contributors to run selftests locally
in the same environment to check if their changes would end up breaking
the BPF CI and reduce the back-and-forth between the maintainers and the
developers.

Tested-by: Jiri Olsa <jolsa@redhat.com>
Signed-off-by: KP Singh <kpsingh@kernel.org>
---
 tools/testing/selftests/bpf/run_in_vm.sh | 356 +++++++++++++++++++++++
 1 file changed, 356 insertions(+)
 create mode 100755 tools/testing/selftests/bpf/run_in_vm.sh

diff --git a/tools/testing/selftests/bpf/run_in_vm.sh b/tools/testing/selftests/bpf/run_in_vm.sh
new file mode 100755
index 000000000000..46fbb0422e9e
--- /dev/null
+++ b/tools/testing/selftests/bpf/run_in_vm.sh
@@ -0,0 +1,356 @@
+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0
+
+set -u
+set -e
+
+# This script currently only works for x86_64, as
+# it is based on the VM image used by the BPF CI which is
+# x86_64.
+QEMU_BINARY="${QEMU_BINARY:="qemu-system-x86_64"}"
+X86_BZIMAGE="arch/x86/boot/bzImage"
+DEFAULT_COMMAND="./test_progs"
+MOUNT_DIR="mnt"
+ROOTFS_IMAGE="root.img"
+OUTPUT_DIR="$HOME/.bpf_selftests"
+KCONFIG_URL="https://raw.githubusercontent.com/libbpf/libbpf/master/travis-ci/vmtest/configs/latest.config"
+INDEX_URL="https://raw.githubusercontent.com/libbpf/libbpf/master/travis-ci/vmtest/configs/INDEX"
+NUM_COMPILE_JOBS="$(nproc)"
+
+usage()
+{
+	cat <<EOF
+Usage: $0 [-k] [-i] [-d <output_dir>] -- [<command>]
+
+<command> is the command you would normally run when you are in
+tools/testing/selftests/bpf. e.g:
+
+	$0 -- ./test_progs -t test_lsm
+
+If no command is specified, "${DEFAULT_COMMAND}" will be run by
+default.
+
+If you build your kernel using KBUILD_OUTPUT= or O= options, these
+can be passed as environment variables to the script:
+
+  O=<kernel_build_path> $0 -- ./test_progs -t test_lsm
+
+or
+
+  KBUILD_OUTPUT=<kernel_build_path> $0 -- ./test_progs -t test_lsm
+
+Options:
+
+	-k)		"Keep the kernel", i.e. don't recompile the kernel if it exists.
+	-i)		Update the rootfs image with a newer version.
+	-d)		Update the output directory (default: ${OUTPUT_DIR})
+	-j)		Number of jobs for compilation, similar to -j in make
+			(default: ${NUM_COMPILE_JOBS})
+EOF
+}
+
+unset URLS
+populate_url_map()
+{
+	if ! declare -p URLS &> /dev/null; then
+		# URLS contain the mapping from file names to URLs where
+		# those files can be downloaded from.
+		declare -gA URLS
+		while IFS=$'\t' read -r name url; do
+			URLS["$name"]="$url"
+		done < <(curl -Lsf ${INDEX_URL})
+	fi
+}
+
+download()
+{
+	local file="$1"
+
+	if [[ ! -v URLS[$file] ]]; then
+		echo "$file not found" >&2
+		return 1
+	fi
+
+	echo "Downloading $file..." >&2
+	curl -Lsf "${URLS[$file]}" "${@:2}"
+}
+
+newest_rootfs_version()
+{
+	{
+	for file in "${!URLS[@]}"; do
+		if [[ $file =~ ^libbpf-vmtest-rootfs-(.*)\.tar\.zst$ ]]; then
+			echo "${BASH_REMATCH[1]}"
+		fi
+	done
+	} | sort -rV | head -1
+}
+
+download_rootfs()
+{
+	local rootfsversion="$1"
+	local dir="$2"
+
+	if ! which zstd &> /dev/null; then
+		echo 'Could not find "zstd" on the system, please install zstd'
+		exit 1
+	fi
+
+	download "libbpf-vmtest-rootfs-$rootfsversion.tar.zst" |
+		zstd -d | sudo tar -C "$dir" -x
+}
+
+recompile_kernel()
+{
+	local kernel_checkout="$1"
+	local make_command="$2"
+
+	cd "${kernel_checkout}"
+
+	${make_command} olddefconfig
+	${make_command}
+}
+
+mount_image()
+{
+	local rootfs_img="${OUTPUT_DIR}/${ROOTFS_IMAGE}"
+	local mount_dir="${OUTPUT_DIR}/${MOUNT_DIR}"
+
+	sudo mount -o loop "${rootfs_img}" "${mount_dir}"
+}
+
+unmount_image()
+{
+	local mount_dir="${OUTPUT_DIR}/${MOUNT_DIR}"
+
+	sudo umount "${mount_dir}" &> /dev/null
+}
+
+update_selftests()
+{
+	local kernel_checkout="$1"
+	local selftests_dir="${kernel_checkout}/tools/testing/selftests/bpf"
+
+	cd "${selftests_dir}"
+	${make_command}
+
+	# Mount the image and copy the selftests to the image.
+	mount_image
+	sudo rm -rf "${mount_dir}/root/bpf"
+	sudo cp -r "${selftests_dir}" "${mount_dir}/root"
+	unmount_image
+}
+
+update_init_script()
+{
+	local init_script_dir="${OUTPUT_DIR}/${MOUNT_DIR}/etc/rcS.d"
+	local init_script="${init_script_dir}/S50-startup"
+	local command="$1"
+	local log_file="$2"
+
+	mount_image
+
+	if [[ ! -d "${init_script_dir}" ]]; then
+		cat <<EOF
+Could not find ${init_script_dir} in the mounted image.
+This likely indicates a bad rootfs image, Please download
+a new image by passing "-i" to the script
+EOF
+		exit 1
+
+	fi
+
+	sudo bash -c "cat >${init_script}" <<EOF
+#!/bin/bash
+
+{
+	cd /root/bpf
+	echo ${command}
+	stdbuf -oL -eL ${command}
+} 2>&1 | tee /root/${log_file}
+poweroff -f
+EOF
+
+	sudo chmod a+x "${init_script}"
+	unmount_image
+}
+
+create_vm_image()
+{
+	local rootfs_img="${OUTPUT_DIR}/${ROOTFS_IMAGE}"
+	local mount_dir="${OUTPUT_DIR}/${MOUNT_DIR}"
+
+	rm -rf "${rootfs_img}"
+	touch "${rootfs_img}"
+	chattr +C "${rootfs_img}" >/dev/null 2>&1 || true
+
+	truncate -s 2G "${rootfs_img}"
+	mkfs.ext4 -q "${rootfs_img}"
+
+	mount_image
+	download_rootfs "$(newest_rootfs_version)" "${mount_dir}"
+	unmount_image
+}
+
+run_vm()
+{
+	local kernel_bzimage="$1"
+	local rootfs_img="${OUTPUT_DIR}/${ROOTFS_IMAGE}"
+
+	if ! which "${QEMU_BINARY}" &> /dev/null; then
+		cat <<EOF
+Could not find ${QEMU_BINARY}
+Please install qemu or set the QEMU_BINARY environment variable.
+EOF
+		exit 1
+	fi
+
+	${QEMU_BINARY} \
+		-nodefaults \
+		-display none \
+		-serial mon:stdio \
+		-cpu kvm64 \
+		-enable-kvm \
+		-smp 4 \
+		-m 2G \
+		-drive file="${rootfs_img}",format=raw,index=1,media=disk,if=virtio,cache=none \
+		-kernel "${kernel_bzimage}" \
+		-append "root=/dev/vda rw console=ttyS0,115200"
+}
+
+copy_logs()
+{
+	local mount_dir="${OUTPUT_DIR}/${MOUNT_DIR}"
+	local log_file="${mount_dir}/root/$1"
+
+	mount_image
+	sudo cp ${log_file} "${OUTPUT_DIR}"
+	sudo rm -f ${log_file}
+	unmount_image
+}
+
+is_rel_path()
+{
+	local path="$1"
+
+	[[ ${path:0:1} != "/" ]]
+}
+
+main()
+{
+	local script_dir="$(cd -P -- "$(dirname -- "${BASH_SOURCE[0]}")" && pwd -P)"
+	local kernel_checkout=$(realpath "${script_dir}"/../../../../)
+	local log_file="$(date +"bpf_selftests.%Y-%m-%d_%H-%M-%S.log")"
+	# By default the script searches for the kernel in the checkout directory but
+	# it also obeys environment variables O= and KBUILD_OUTPUT=
+	local kernel_bzimage="${kernel_checkout}/${X86_BZIMAGE}"
+	local command="${DEFAULT_COMMAND}"
+	local kernel_recompile="yes"
+	local update_image="no"
+
+	while getopts 'hkid:j:' opt; do
+		case ${opt} in
+		k)
+			kernel_recompile="no"
+			;;
+		i)
+			update_image="yes"
+			;;
+		d)
+			OUTPUT_DIR="$OPTARG"
+			;;
+		j)
+			NUM_COMPILE_JOBS="$OPTARG"
+			;;
+		h)
+			usage
+			exit 0
+			;;
+		\? )
+			echo "Invalid Option: -$OPTARG"
+			usage
+			exit 1
+			;;
+		: )
+			echo "Invalid Option: -$OPTARG requires an argument"
+			usage
+			exit 1
+			;;
+		esac
+	done
+	shift $((OPTIND -1))
+
+	if [[ $# -eq 0 ]]; then
+		echo "No command specified, will run ${DEFAULT_COMMAND} in the vm"
+	else
+		command="$@"
+	fi
+
+	local kconfig_file="${OUTPUT_DIR}/latest.config"
+	local make_command="make -j ${NUM_COMPILE_JOBS} KCONFIG_CONFIG=${kconfig_file}"
+
+	# Figure out where the kernel is being built.
+	# O takes precedence over KBUILD_OUTPUT.
+	if [[ "${O:=""}" != "" ]]; then
+		if is_rel_path "${O}"; then
+			O="$(realpath "${PWD}/${O}")"
+		fi
+		kernel_bzimage="${O}/${X86_BZIMAGE}"
+		make_command="${make_command} O=${O}"
+	elif [[ "${KBUILD_OUTPUT:=""}" != "" ]]; then
+		if is_rel_path "${KBUILD_OUTPUT}"; then
+			KBUILD_OUTPUT="$(realpath "${PWD}/${KBUILD_OUTPUT}")"
+		fi
+		kernel_bzimage="${KBUILD_OUTPUT}/${X86_BZIMAGE}"
+		make_command="${make_command} KBUILD_OUTPUT=${KBUILD_OUTPUT}"
+	fi
+
+	populate_url_map
+
+	local rootfs_img="${OUTPUT_DIR}/${ROOTFS_IMAGE}"
+	local mount_dir="${OUTPUT_DIR}/${MOUNT_DIR}"
+
+	echo "Output directory: ${OUTPUT_DIR}"
+
+	mkdir -p "${OUTPUT_DIR}"
+	mkdir -p "${mount_dir}"
+	curl -Lsf "${KCONFIG_URL}" -o "${kconfig_file}"
+
+	if [[ "${kernel_recompile}" == "no" && ! -f "${kernel_bzimage}" ]]; then
+		echo "Kernel image not found in ${kernel_bzimage}, kernel will be recompiled"
+		kernel_recompile="yes"
+	fi
+
+	if [[ "${kernel_recompile}" == "yes" ]]; then
+		recompile_kernel "${kernel_checkout}" "${make_command}"
+	fi
+
+	if [[ "${update_image}" == "no" && ! -f "${rootfs_img}" ]]; then
+		echo "rootfs image not found in ${rootfs_img}"
+		update_image="yes"
+	fi
+
+	if [[ "${update_image}" == "yes" ]]; then
+		create_vm_image
+	fi
+
+	update_selftests "${kernel_checkout}" "${make_command}"
+	update_init_script "${command}" "${log_file}"
+	run_vm "${kernel_bzimage}"
+	copy_logs "${log_file}"
+	echo "Logs saved in ${OUTPUT_DIR}/${log_file}"
+}
+
+catch()
+{
+	local exit_code=$1
+	# This is just a cleanup and the directory may
+	# have already been unmounted. So, don't let this
+	# clobber the error code we intend to return.
+	unmount_image || true
+	exit ${exit_code}
+}
+
+trap 'catch "$?"' EXIT
+
+main "$@"
-- 
2.30.0.365.g02bc693789-goog

[PATCH bpf-next v3 2/2] bpf/selftests: Add a short note about run_in_vm.sh in README.rst

[KP Singh]

Add a short note to make contributors aware of the existence of the
script. The documentation does not intentionally document all the
options of the script to avoid mentioning it in two places (it's
available in the usage / help message of the script).

Signed-off-by: KP Singh <kpsingh@kernel.org>
---
 tools/testing/selftests/bpf/README.rst | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/tools/testing/selftests/bpf/README.rst b/tools/testing/selftests/bpf/README.rst
index ca064180d4d0..80ddcce8df02 100644
--- a/tools/testing/selftests/bpf/README.rst
+++ b/tools/testing/selftests/bpf/README.rst
@@ -6,6 +6,30 @@ General instructions on running selftests can be found in
 
 __ /Documentation/bpf/bpf_devel_QA.rst#q-how-to-run-bpf-selftests
 
+=========================
+Running Selftests in a VM
+=========================
+
+It's now possible to run the selftests using ``tools/testing/selftests/bpf/run_in_vm.sh``.
+The script tries to ensure that the tests are run with the same environment as they
+would be run post-submit in the CI used by the Maintainers.
+
+This script downloads a suitable Kconfig and VM userspace image from the system used by
+the CI. It builds the kernel (without overwriting your existing Kconfig), recompiles the
+bpf selftests, runs them (by default ``tools/testing/selftests/bpf/test_progs``) and
+saves the resulting output (by default in ``~/.bpf_selftests``).
+
+For more information on about using the script, run:
+
+.. code-block:: console
+
+  $ tools/testing/selftests/bpf/run_in_vm.sh -h
+
+.. note:: The script uses pahole and clang based on host environment setting.
+          If you want to change pahole and llvm, you can change `PATH` environment
+          variable in the beginning of script.
+
+.. note:: The script currently only supports x86_64.
 
 Additional information about selftest failures are
 documented here.
-- 
2.30.0.365.g02bc693789-goog