arm64: virtio_blk is not included in the initramfs

[Alfonso Sanchez-Beato]

The virtio_blk module is not included by default in the initramfs for arm64, so UC20 cannot boot as expected.

[Juerg Haefliger (juergh)]

What exactly are you trying to do? virtio_blk is not required to boot UC20 on real HW...

[Alfonso Sanchez-Beato (alfonsosanchezbeato)]

I'm trying to boot UC20 on qemu. Note that the module is present in the x86 initramfs, and we can use UC20 on qemu/x86.

[Dimitri John Ledkov (xnox)]

$ git grep virtio_blk
features/server/usr/lib/modules-load.d/ubuntu-core-server.conf:virtio_blk

When building initrd into the generic arm64 kernel snap, we should enable feature "server" like we do on x86.

[Dimitri John Ledkov (xnox)]

Doing this in "kernel-snaps-uc20" git repo would be tricky, as at the moment we don't pass any option when making kernel snaps.

Otherwise core-initd itself defaults to "main server" on x86, but just "main" on all other arches. Maybe we should enable "server" features for "generic" kernel flavours always.

[Dimitri John Ledkov (xnox)]

Something like this https://github.com/snapcore/core-initrd/pull/34/files should do it. Plus respinning the pc-kernel arm64 & armhf kernel snaps.