Re: [PATCH v2 5/5] automation: add x86-64 livepatching test

["Roger Pau Monné" <roger.pau@citrix.com>]

On Wed, Nov 29, 2023 at 07:03:10PM -0800, Stefano Stabellini wrote:
> On Tue, 28 Nov 2023, Roger Pau Monne wrote:
> > Introduce a new gitlab tests for livepatching, using livepatch-build-tools,
> > which better reflects how downstreams build live patches rather than the
> > in-tree tests.
> > 
> > The tests applies the dummy in-tree patch example, checks that the patch is
> > applied correctly and then reverts and unloads it.
> > 
> > Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
> > ---
> >  automation/gitlab-ci/build.yaml               |  8 +++
> >  automation/gitlab-ci/test.yaml                |  8 +++
> >  automation/scripts/build                      | 21 ++++++
> >  .../scripts/qemu-alpine-x86_64-livepatch.sh   | 68 +++++++++++++++++++
> >  4 files changed, 105 insertions(+)
> >  create mode 100755 automation/scripts/qemu-alpine-x86_64-livepatch.sh
> > 
> > diff --git a/automation/gitlab-ci/build.yaml b/automation/gitlab-ci/build.yaml
> > index 32af30ccedc9..22026df51b87 100644
> > --- a/automation/gitlab-ci/build.yaml
> > +++ b/automation/gitlab-ci/build.yaml
> > @@ -358,6 +358,14 @@ alpine-3.18-gcc-debug:
> >    variables:
> >      CONTAINER: alpine:3.18
> >  
> > +alpine-3.18-gcc-livepatch:
> > +  extends: .gcc-x86-64-build
> > +  variables:
> > +    CONTAINER: alpine:3.18
> > +    LIVEPATCH: y
> > +    EXTRA_XEN_CONFIG: |
> > +      CONFIG_LIVEPATCH=y
> > +
> >  debian-stretch-gcc-debug:
> >    extends: .gcc-x86-64-build-debug
> >    variables:
> > diff --git a/automation/gitlab-ci/test.yaml b/automation/gitlab-ci/test.yaml
> > index 6aabdb9d156f..58a90be5ed0e 100644
> > --- a/automation/gitlab-ci/test.yaml
> > +++ b/automation/gitlab-ci/test.yaml
> > @@ -459,3 +459,11 @@ qemu-smoke-ppc64le-powernv9-gcc:
> >    needs:
> >      - qemu-system-ppc64-8.1.0-ppc64-export
> >      - debian-bullseye-gcc-ppc64le-debug
> > +
> > +qemu-alpine-x86_64-gcc-livepatch:
> > +  extends: .qemu-x86-64
> > +  script:
> > +    - ./automation/scripts/qemu-alpine-x86_64-livepatch.sh 2>&1 | tee ${LOGFILE}
> > +  needs:
> > +    - *x86-64-test-needs
> > +    - alpine-3.18-gcc-livepatch
> > diff --git a/automation/scripts/build b/automation/scripts/build
> > index b3c71fb6fb60..0a0a6dceb08c 100755
> > --- a/automation/scripts/build
> > +++ b/automation/scripts/build
> > @@ -103,3 +103,24 @@ else
> >      cp -r dist binaries/
> >      if [[ -f xen/xen ]] ; then cp xen/xen binaries/xen; fi
> >  fi
> > +
> > +if [[ "$LIVEPATCH" == "y" ]]; then
> > +    # Build a test livepatch using livepatch-build-tools.
> > +
> > +    if [[ "$XEN_TARGET_ARCH" != "x86_64" ]]; then
> > +        exit 1
> > +    fi
> > +
> > +    # git diff --no-index returns 0 if no differences, otherwise 1.
> > +    git diff --no-index --output=test.patch xen/arch/x86/test-smc-lp.c \
> > +                                            xen/arch/x86/test-smc-lp-alt.c && exit 1
> > +
> > +    BUILDID=$(readelf -Wn xen/xen-syms | sed -n -e 's/^.*Build ID: //p')
> > +
> > +    git clone https://xenbits.xen.org/git-http/livepatch-build-tools.git
> > +    cd livepatch-build-tools
> > +    make
> > +    ./livepatch-build -s ../ -p ../test.patch -o out -c ../xen/.config \
> > +        --depends $BUILDID --xen-depends $BUILDID
> > +    cp out/test.livepatch ../binaries/test.livepatch
> > +fi
> 
> I realize this is a matter of taste but if possible I would move this to
> qemu-alpine-x86_64-livepatch.sh not to make the build script too
> complex.

I've attempted that, but there are some issues.  First, the
elfutils-dev package would need to be added to the test container,
checkout livepatch-build-tools.git from the test script, and do the
differential build in the test script, so all the Xen hypervisor build
dependencies would also be needed in the test container.

> Otherwise, plase create automation/scripts/livepatch and move this code
> there. You can call automation/scripts/livepatch from
> automation/scripts/build.

Unless you have a strong desire to pursue building the livepatch in
the test step, I will go with the route proposed here, and split the
livepatch build into automation/scripts/build-livepatch.

> Other than that, this is great! I'll let other review the livepatch
> specific changes in this series

Thanks, will post a new version soon.

Roger.