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

[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.

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
> 

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