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ryuheechul/build-accelerated-kvm-guest-custom-kernel-for-wsl2.md

Last active October 1, 2025 17:06
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  1. ryuheechul revised this gist Apr 12, 2023. No changes.
  2. ryuheechul revised this gist Apr 12, 2023. 1 changed file with 1 addition and 1 deletion.
    2 changes: 1 addition & 1 deletion build-accelerated-kvm-guest-custom-kernel-for-wsl2.md
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    _I'm not an author the blog post and this gist is a simply a note on my usage based on the original post, https://boxofcables.dev/kvm-optimized-custom-kernel-wsl2-2022/._
    _I'm not the author the blog post and this gist is a simply a note on my usage based on the original post, https://boxofcables.dev/kvm-optimized-custom-kernel-wsl2-2022/._

    _I also changed the code that extract the latest to a concrete linux kernel version._

  3. ryuheechul created this gist Apr 12, 2023.
    44 changes: 44 additions & 0 deletions build-accelerated-kvm-guest-custom-kernel-for-wsl2.md
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    _I'm not an author the blog post and this gist is a simply a note on my usage based on the original post, https://boxofcables.dev/kvm-optimized-custom-kernel-wsl2-2022/._

    _I also changed the code that extract the latest to a concrete linux kernel version._

    First start with [openSUSE Tumbleweed distro](https://www.microsoft.com/store/productId/9MSSK2ZXXN11) and commands below can be used to build the custom kernel and set it to be used for WSL2 distros.

    ```bash
    # prepare build deps
    sudo zypper -n up
    # original from the post
    sudo bash -c "zypper in -y -t pattern devel_basis && zypper in -y bc openssl openssl-devel dwarves rpm-build libelf-devel aria2 jq"
    # what I ended up doing instead
    sudo zypper install -y aria2 make gcc bison flex bc libelf-devel libopenssl-3-devel dwarves

    # download and unpack kernel source code and cd into it
    echo 'https://github.com/microsoft/WSL2-Linux-Kernel/archive/refs/tags/linux-msft-wsl-6.1.21.1.tar.gz' | aria2c -i -
    tar -xf *.tar.gz
    cd WSL2-Linux-Kernel-linux-msft-wsl-6.1.21.1/

    # modify config
    cp Microsoft/config-wsl .config
    sed -i 's/# CONFIG_KVM_GUEST is not set/CONFIG_KVM_GUEST=y/g' .config
    sed -i 's/# CONFIG_ARCH_CPUIDLE_HALTPOLL is not set/CONFIG_ARCH_CPUIDLE_HALTPOLL=y/g' .config
    sed -i 's/# CONFIG_HYPERV_IOMMU is not set/CONFIG_HYPERV_IOMMU=y/g' .config
    sed -i '/^# CONFIG_PARAVIRT_TIME_ACCOUNTING is not set/a CONFIG_PARAVIRT_CLOCK=y' .config
    sed -i '/^# CONFIG_CPU_IDLE_GOV_TEO is not set/a CONFIG_CPU_IDLE_GOV_HALTPOLL=y' .config
    sed -i '/^CONFIG_CPU_IDLE_GOV_HALTPOLL=y/a CONFIG_HALTPOLL_CPUIDLE=y' .config
    sed -i 's/CONFIG_HAVE_ARCH_KCSAN=y/CONFIG_HAVE_ARCH_KCSAN=n/g' .config
    sed -i '/^CONFIG_HAVE_ARCH_KCSAN=n/a CONFIG_KCSAN=n' .config

    # build kernel
    make -j 8

    # move kernel to Windows host
    powershell.exe /C 'Copy-Item .\arch\x86\boot\bzImage $env:USERPROFILE'
    # print '$env:USERPROFILE\.wslconfig' just in case it existed before
    cat /mnt/c/Users/$(powershell.exe '$env:USERNAME')/.wslconfig
    # set kernel file path to '$env:USERPROFILE\.wslconfig'
    powershell.exe /C 'Write-Output [wsl2]`nkernel=$env:USERPROFILE\bzImage | % {$_.replace("\","\\")} | Out-File $env:USERPROFILE\.wslconfig -encoding ASCII'
    # verify the content
    cat /mnt/c/Users/$(powershell.exe '$env:USERNAME')/.wslconfig
    ```

    And now this built kernel be the kernel for all wsl distros not just for openSUSE one unless the setting gets reversed later.