Merge branch 'BPF selftest helper script'

KP Singh says:

====================

# v4 -> v5

- Use %Y (modification time) instead of %W (creation time) of the local
  copy of the kernel config to check for newer upstream config.
- Rename the script to vmtest.sh

# v3 -> v4

- Fix logic for updating kernel config to not download the file
  if there are no upstream modifications and avoid extraneous
  kernel compilation as suggested by Andrii.
- This also removes the need for the -k flag.

# 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 se
====================

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
This commit is contained in:
Andrii Nakryiko 2021-02-04 16:03:17 -08:00
commit ec45c5faa2
2 changed files with 392 additions and 0 deletions

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@ -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/vmtest.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/vmtest.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.

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@ -0,0 +1,368 @@
#!/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"
KCONFIG_API_URL="https://api.github.com/repos/libbpf/libbpf/contents/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 [-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:
-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} != "/" ]]
}
update_kconfig()
{
local kconfig_file="$1"
local update_command="curl -sLf ${KCONFIG_URL} -o ${kconfig_file}"
# Github does not return the "last-modified" header when retrieving the
# raw contents of the file. Use the API call to get the last-modified
# time of the kernel config and only update the config if it has been
# updated after the previously cached config was created. This avoids
# unnecessarily compiling the kernel and selftests.
if [[ -f "${kconfig_file}" ]]; then
local last_modified_date="$(curl -sL -D - "${KCONFIG_API_URL}" -o /dev/null | \
grep "last-modified" | awk -F ': ' '{print $2}')"
local remote_modified_timestamp="$(date -d "${last_modified_date}" +"%s")"
local local_creation_timestamp="$(stat -c %Y "${kconfig_file}")"
if [[ "${remote_modified_timestamp}" -gt "${local_creation_timestamp}" ]]; then
${update_command}
fi
else
${update_command}
fi
}
main()
{
local script_dir="$(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 update_image="no"
while getopts 'hkid:j:' opt; do
case ${opt} in
i)
update_image="yes"
;;
d)
OUTPUT_DIR="$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 "${mount_dir}"
update_kconfig "${kconfig_file}"
recompile_kernel "${kernel_checkout}" "${make_command}"
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 "$@"