[meta-virtualization] [PATCH V3 2/3] linux-yocto: make bbappend have effect conditionally

[Christopher Clark]

On Mon, Sep 25, 2017 at 8:31 PM, Chen Qi <Qi.Chen at windriver.com> wrote:
> Make these bbappend files to take effect only when DISTRO_FEATURES
> contain 'virtualization'. Otherwise, we would meet failure failure
> at system booting up qemux86. Related logs are as below.
>
>  systemd-modules-load[113]: Failed to insert 'kvm_amd': Operation not supported
>  systemd-modules-load[113]: Failed to insert 'kvm_intel': Operation not supported
>
> Signed-off-by: Chen Qi <Qi.Chen at windriver.com>
...
> diff --git a/recipes-kernel/linux/linux-yocto_virtualization.inc b/recipes-kernel/linux/linux-yocto_virtualization.inc
> new file mode 100644
> index 0000000..8b296d7
> --- /dev/null
> +++ b/recipes-kernel/linux/linux-yocto_virtualization.inc
> @@ -0,0 +1,20 @@
> +FILESEXTRAPATHS_prepend := "${THISDIR}/linux-yocto:"
> +
> +SRC_URI += "file://xt-checksum.scc \
> +            file://ebtables.scc \
> +           file://vswitch.scc \
> +           file://lxc.scc \
> +            file://docker.scc \
> +           "
> +KERNEL_FEATURES_append = " features/kvm/qemu-kvm-enable.scc"
> +
> +KERNEL_MODULE_AUTOLOAD += "openvswitch"
> +KERNEL_MODULE_AUTOLOAD += "kvm"
> +KERNEL_MODULE_AUTOLOAD += "kvm-amd"
> +KERNEL_MODULE_AUTOLOAD += "kvm-intel"
> +
> +# aufs kernel support required for xen-image-minimal
> +KERNEL_FEATURES_append += "${@bb.utils.contains('DISTRO_FEATURES', 'aufs', ' features/aufs/aufs-enable.scc', '', d)}"
> +
> +# xen kernel support
> +SRC_URI += "${@bb.utils.contains('DISTRO_FEATURES', 'xen', ' file://xen.scc', '', d)}"
> --
> 2.11.0
>
> --

Suggestion for a preferred change: make the KVM features depend on
DISTRO_FEATURES containing 'kvm', in the same way that the Xen
features do for DISTRO_FEATURES containing 'xen'.

Here's why: those KVM kernel modules are not of interest on Xen
systems. With this change, you're removing the KVM features from the
qemu build to solve your bug in hand, by making it conditional on
'virtualization', but is still leaves them present when only Xen is
needed.

With that change, I'm not sure whether a 'virtualization' disto
feature is immediately useful. It could make sense for features that
are hypervisor-agnostic but I don't have an immediate example to point
to.

Christopher