README.md

MPTCP Upstream Virtme Docker

This repo contains files to build a virtual environment with Virtme to validate mptcp_net-next repo.

The idea here is to have automatic builds to publish a docker image that can be used by devs and CI.

Entrypoint options

When launching the docker image, you have to specify the mode you want to use:

• manual-*: Build the kernel and dependences, start a VM, then leave you with a shell prompt inside the VM:
  • manual-normal: With a non-debug kernel config.
  • manual-debug: With a debug kernel config.
  • manual-btf: With BTF support (needed for BPF features).
• auto-*: Build the kernel and dependences, start a VM, then run all the automatic tests from the VM:
  • auto-normal: With a non-debug kernel config.
  • auto-debug: With a debug kernel config.
  • auto-all: First with a non-debug, then a debug kernel config.
  • auto-btf: With BTF support (needed for BPF features).
• make: Run the make command with optional parameters.
• make.cross: Run Intel's make.cross command with optional parameters.
• cmd: Run the given command in the docker image (not in the VM), e.g. cmd bash to have a prompt
• src: source a given script file.
• help: display all possible commands.

All the manual-* and auto-* options accept optional arguments for scripts/config script from the kernel source code, e.g. -e DEBUG_LOCKDEP

How to use

User mode

Without cloning this repo, you can quickly get a ready to use environment:

cd <kernel source code>
docker run -v "${PWD}:${PWD}:rw" -w "${PWD}" --privileged --rm -it \
  --pull always mptcp/mptcp-upstream-virtme-docker:latest \
  <entrypoint options, see above>

This docker image needs to be executed with --privileged option to be able to execute QEmu with KVM acceleration.

Developer mode

Clone this repo, then:

cd <kernel source code>
/PATH/TO/THIS/REPO/run-tests-dev.sh <entrypoint options, see above>

This will build and start the docker image.

To avoid using long paths, you can create symlinks:

cd <kernel source code>
ln -s /PATH/TO/THIS/REPO/run-tests-dev.sh .virtme.sh
ln -s /PATH/TO/THIS/REPO/run-tests-dev-clang.sh .virtme-clang.sh

Then simply call ./.virtme.sh or .virtme-clang.sh.

Extension

Files

3 files can be created in the root dir of the kernel source code:

• .virtme-exec-pre
• .virtme-exec-run
• .virtme-exec-post

pre and post are run before and after the tests' suite. run is run instead of the tests' suite.

These scripts are sourced and can use functions from the virtme script.

Env vars

Env vars can be set to change the behaviour of the script. When using the Docker command, you need to specify the -e parameter, e.g. to set INPUT_BUILD_SKIP=1:

docker run -e INPUT_BUILD_SKIP=1 (...) mptcp/mptcp-upstream-virtme-docker:latest (...)

Skip kernel build

If you didn't change the kernel code, it can be useful to skip the compilation part. You can then set INPUT_BUILD_SKIP=1 to save a few seconds to start the VM.

Use CLang instead of GCC

Simply set INPUT_CLANG=1 env var with all the commands you use.

Not blocking with questions

You can set INPUT_NO_BLOCK=1 env var not to block if these files are present. This is useful if you need to do a git bisect.

Not stop after an error is detected with run_loop

You can set INPUT_RUN_LOOP_CONTINUE=1 env var to continue even if an error is detected. Failed iterations are logged in ${CONCLUSION}.failed.

Packetdrill

You can set INPUT_PACKETDRILL_STABLE=1 env var to use the branch for the current kernel version instead of the dev version following MPTCP net-next.

You can set INPUT_PACKETDRILL_NO_SYNC=1 env var not to sync Packetdrill with upstream. This is useful if you mount a local packetdrill repo in the image.

You can also set INPUT_PACKETDRILL_NO_MORE_TOLERANCE=1 not to increase Packetdrill's tolerances.

If you run the Docker commands directly, you can use:

docker run \
  -e INPUT_PACKETDRILL_NO_SYNC=1 \
  -e INPUT_PACKETDRILL_NO_MORE_TOLERANCE=1 \
  -v /PATH/TO/packetdrill:/opt/packetdrill:rw \
  -v "${PWD}:${PWD}:rw" -w "${PWD}" \
  --privileged --rm -it \
  mptcp/mptcp-upstream-virtme-docker:latest \
  manual

cd /opt/packetdrill/gtests/net/
./packetdrill/run_all.py -lv mptcp/dss ## or any other subdirs

# or
cd /opt/packetdrill/gtests/net/mptcp/dss/ ## or any other subdirs
../../packetdrill/packetdrill -v dss_fin_server.pkt ## or any other tests

If you use the run*.sh scripts, you can set VIRTME_PACKETDRILL_PATH to do this mount and set the proper env var.

VIRTME_PACKETDRILL_PATH=/PATH/TO/packetdrill \
  /PATH/TO/THIS/REPO/run-tests-dev.sh <entrypoint options, see above>

If packetdrill itself is modified and to continue to use the same build environment, the recompilation can also be done from the running docker image:

docker exec -w /opt/packetdrill/gtests/net/packetdrill -it \
  $(docker ps --filter ancestor=mptcp/mptcp-upstream-virtme-docker --format='{{.ID}}') \
    make

Using for other subsystems than MPTCP

These project has been initially created to validate modifications done in MPTCP Upstream project. But it can also be used to validate other subsystems. Here are a few tips to use it elsewhere:

• If you only need to run extra steps at the "preparation" phase but keeping the same docker image, write them in a .virtme-prepare-post file, e.g. to compile iproute2 differently.

• Similar to the previous point, you might prefer to extend the docker image not to have to install new packages from .virtme-prepare-post each time you run the docker image. You can use our docker image as a base and then install other dependences:

  FROM mptcp/mptcp-upstream-virtme-docker:latest
  
  RUN apt-get update && apt-get install -y python3-pip python3-scapy

• Skip the build steps you don't need, e.g.

  docker run (...) \
      -e INPUT_BUILD_SKIP_PERF=1 \
      -e INPUT_BUILD_SKIP_SELFTESTS=1 \
      -e INPUT_BUILD_SKIP_PACKETDRILL=1 \
      (...) \
      mptcp/mptcp-upstream-virtme-docker \
      auto-normal

• Specify the path to another selftests dir to test by using INPUT_SELFTESTS_DIR env var, e.g.

  docker run (...) \
      -e INPUT_SELFTESTS_DIR=tools/testing/selftests/tc-testing
      (...)

• Use .virtme-exec-run file (and similar) to execute different tests, see above.

An example:

# Better to extend the docker image (but quick solution here), see above:
cat <<'EOF' > ".virtme-prepare-post"
apt-get update && apt-get install -y python3-pip python3-scapy
EOF

# Only run the selftests
cat <<'EOF' > ".virtme-exec-run"
run_selftest_all
EOF

# skip Packetdrill build (not needed), run TC selftests and add CONFIG_DUMMY
docker run -v "${PWD}:${PWD}:rw" -w "${PWD}" --privileged --rm -it \
  -e INPUT_BUILD_SKIP_PACKETDRILL=1 \
  -e INPUT_SELFTESTS_DIR=tools/testing/selftests/tc-testing \
  --pull always mptcp/mptcp-upstream-virtme-docker:latest \
  auto-normal -e DUMMY

Feel free to contact us and/or open Pull Requests to support more cases.

Compilation issues with Perf or Objtools

If you see such messages:

Makefile.config:458: *** No gnu/libc-version.h found, please install glibc-dev[el].  Stop.

This can happen when switching between major versions of the compiler. In this case, it will be required to clean the build dir in .virtme/build, e.g.

docker run -v "${PWD}:${PWD}:rw" -w "${PWD}" --rm -it \
  mptcp/mptcp-upstream-virtme-docker:latest \
  cmd rm -r .virtme/build*/tools

Working with VSCode

If you use VSCode for Linux kernel development add-on, you can configure it to use this docker image: simply copy all files from the vscode directory in your .vscode dir from the kernel source (or use symbolic links). .clangd needs to be placed at the root of the kernel source directory.

Notes:

• The VSCode add-on needs some modifications, see PR #5 and PR #6. If these PRs are not merged, you can use this fork (virtme-support branch) for the moment.
• CLang will be used by VSCode instead of GCC. It is then required to launch all docker commands with -e INPUT_CLANG=1, see above.
• CLangD will be used on the host machine, not in the Docker.