Re: [PATCH 1/1] Add support to build binary version of DKMS kernel modules

[Henning Schild <henning.schild@siemens.com>]

Am Wed, 14 Apr 2021 11:03:50 +0200
schrieb Jan Kiszka <jan.kiszka@siemens.com>:

> On 14.04.21 10:52, Henning Schild wrote:
> > Hi Felix,
> > 
> > thanks for pushing this one upstream.
> > 
> > We will need a testcase for it, so make sure to enter into
> > "scripts/ci_build.sh"
> > 
> > I would suggest the virtualbox modules or maybe vmware modules
> > instead. This way we would probably have more distro coverage and
> > in fact have a useful example for people doing virtualbox (the one
> > i would prefer). Not sure that is possible or why you picked dpdk.  
> 
> None of those crappy modules will build on non-x86. We should look
> for a portable example.

Yes ideally we find a dkms package that exists on all distros and
arches, not sure that exists. Would also allow testing the Isar
crossbuild on that feature.

If cross causes issues ISAR_CROSS_COMPILE = "0" in the class might be
acceptable, would be to me.

If we do not find such a generic module, all i said is that vbox is
probably more useful than igb_uio. And probably more available across
distros.

Henning


> Jan
> 
> > 
> > Am Wed, 14 Apr 2021 10:36:17 +0200
> > schrieb Felix Moessbauer <felix.moessbauer@siemens.com>:
> >   
> >> This patch adds support to build and install a kernel module that
> >> is available via a debian DKMS package.
> >> As it is hard to directly build and install the package we create
> >> and distribute a meta package that is independent of the kernel
> >> version. In that package, we depend on the versioned prebuild
> >> kernel module package.
> >>
> >> To build the dkms module, we add two tasks and directly
> >> use dkms to build the debian package containing the binary module
> >> Then we just copy the binary-module debian package to the workdir,
> >>
> >> Signed-off-by: Felix Moessbauer <felix.moessbauer@siemens.com>
> >> ---
> >>  .../example-dkms-module/igb-uio_20.11.bb      | 14 ++++
> >>  meta/classes/dkms-module.bbclass              | 68
> >> +++++++++++++++++++ 2 files changed, 82 insertions(+)
> >>  create mode 100644
> >> meta-isar/recipes-kernel/example-dkms-module/igb-uio_20.11.bb
> >> create mode 100644 meta/classes/dkms-module.bbclass
> >>
> >> diff --git
> >> a/meta-isar/recipes-kernel/example-dkms-module/igb-uio_20.11.bb
> >> b/meta-isar/recipes-kernel/example-dkms-module/igb-uio_20.11.bb new
> >> file mode 100644 index 0000000..abb9922 --- /dev/null
> >> +++ b/meta-isar/recipes-kernel/example-dkms-module/igb-uio_20.11.bb
> >> @@ -0,0 +1,14 @@
> >> +# Example recipe for building the binary version of a DKMS module
> >> +#
> >> +# This software is a part of ISAR.
> >> +# Copyright (c) Siemens AG, 2018
> >> +#
> >> +# SPDX-License-Identifier: MIT
> >> +
> >> +inherit dkms-module
> >> +
> >> +PN .= "-${KERNEL_NAME}"
> >> +
> >> +#package name (without -dkms. E.g "dpdk-kmods" for package
> >> "dpdk-kmods-dkms") +DKMS_PACKAGE_NAME = "dpdk-kmods"
> >> +AUTOLOAD += "igb_uio"
> >> diff --git a/meta/classes/dkms-module.bbclass
> >> b/meta/classes/dkms-module.bbclass new file mode 100644
> >> index 0000000..d1dbba9
> >> --- /dev/null
> >> +++ b/meta/classes/dkms-module.bbclass
> >> @@ -0,0 +1,68 @@
> >> +# This software is a part of ISAR.
> >> +# Copyright (C) 2021 Siemens AG
> >> +#
> >> +# SPDX-License-Identifier: MIT
> >> +
> >> +inherit dpkg-raw
> >> +
> >> +# Build and install a kernel module that is available via a debian
> >> DKMS package. +# As it is hard to directly build and install the
> >> package we create and distribute +# a meta package that is
> >> independent of the kernel version. +# In that package, we depend on
> >> the versioned prebuild kernel module package. +#
> >> +# To build the dkms module, we add two tasks and directly
> >> +# use dkms to build the debian package containing the binary
> >> module +# Then we just copy the binary-module debian package to
> >> the workdir, +# so ISAR's do_deploy_deb picks it up.
> >> +
> >> +#package name (without -dkms. E.g "dpdk-kmods" for package
> >> "dpdk-kmods-dkms") +DKMS_PACKAGE_NAME ?= ""
> >> +AUTOLOAD ?= ""
> >> +
> >> +DESCRIPTION ?= "Kernel module from DKMS package for ${PN}"
> >> +DEPENDS += "linux-headers-${KERNEL_NAME}"
> >> +DEBIAN_DEPENDS += "${DKMS_PACKAGE_NAME}-modules,"
> >> +DEBIAN_BUILD_DEPENDS += "linux-headers-${KERNEL_NAME},
> >> ${DKMS_PACKAGE_NAME}-dkms," +
> >> +# install configuration to auto-load the modules in ${AUTOLOAD}
> >> +do_install() {
> >> +    # auto load the module
> >> +    install -v -d ${D}/etc/modules-load.d
> >> +    for module in "${AUTOLOAD}"; do
> >> +        echo $module > ${D}/etc/modules-load.d/${PN}.conf
> >> +    done  
> > 
> > I think this might need an "update-initramfs -u" in postinst, but i
> > am not sure, check the other autoloader code and see if you can
> > share. Such modules probably do not need early loading in initrd,
> > but "/etc/modules-load.d" is mirrored into the initrd so we should
> > not get out of sync.
> > It is important that both autoloaders do the same or similar things,
> > initrd could stay open if the other one also does not care.
> > 
> > Henning
> >   
> >> +}
> >> +
> >> +# build the binary kernel module and package as debian package
> >> (versioned) +do_module_build() {
> >> +    # we have to find out the module version, e.g.
> >> dpdk-kmods/0~20201113+git -k 5.10.0-3-rt-amd64/x86_64
> >> +    REVISION=$(find
> >> ${BUILDCHROOT_DIR}/usr/src/${DKMS_PACKAGE_NAME}-* -type d -exec
> >> basename {} + | sed 's/${DKMS_PACKAGE_NAME}-//g')
> >> +    if ! dpkg -s --root=${BUILDCHROOT_DIR}
> >> linux-headers-${KERNEL_NAME} | grep "Depends:.*linux-headers"; then
> >> +        # custom kernels directly place their files in
> >> linux-image-KERNEL-NAME, instead
> >> +        # of using a meta package + a versioned package with the
> >> resources
> >> +        # The prebuild DKMS binary package depends on the
> >> versioned kernel package,
> >> +        # but that is not available on custom kernels. Hence, we
> >> just remove the dependency.
> >> +        bbnote "Building ${DKMS_PACKAGE_NAME} for custom kernel
> >> ${KERNEL_NAME}"
> >> +        cp
> >> ${BUILDCHROOT_DIR}/etc/dkms/template-dkms-mkbmdeb/debian/control
> >> ${WORKDIR}/control.dkms.orig
> >> +        sudo sed -i 's/, linux-image-KERNEL_VERSION//'
> >> ${BUILDCHROOT_DIR}/etc/dkms/template-dkms-mkbmdeb/debian/control
> >> +    fi
> >> +    # build the module for all installed kernels (should be just
> >> one)
> >> +    sudo -E chroot ${BUILDCHROOT_DIR} dkms mkbmdeb
> >> ${DKMS_PACKAGE_NAME}/${REVISION} --all
> >> +    DKMS_PACKAGE_VERSIONED=$(find
> >> ${BUILDCHROOT_DIR}/var/lib/dkms/${DKMS_PACKAGE_NAME}/ -name
> >> "${DKMS_PACKAGE_NAME}-modules*.deb" -exec dpkg -I {} + | grep
> >> "Package:" | awk '{print $2}')
> >> +    if [ -z "$DKMS_PACKAGE_VERSIONED" ]; then
> >> +        bberror "No prebuild dkms module found"
> >> +        exit 1
> >> +    fi
> >> +    # restore dkms template (if any)
> >> +    cp ${WORKDIR}/control.dkms.orig
> >> ${BUILDCHROOT_DIR}/etc/dkms/template-dkms-mkbmdeb/debian/control ||
> >> true +} +
> >> +# simply copy our module from the build tree to the expected
> >> output location +# of this recipe. Then, do_deploy_dep finds it
> >> and adds it to the +# debian isar repo
> >> +do_module_deploy() {
> >> +    cp
> >> ${BUILDCHROOT_DIR}/var/lib/dkms/${DKMS_PACKAGE_NAME}/*/bmdeb/*.deb
> >> ${S}/../ +} +
> >> +addtask module_build after do_install_builddeps before
> >> do_dpkg_build +addtask module_deploy after do_module_build before
> >> do_deploy_deb  
> >   
>