Full Disk Encryption with xchacha12,aes-adiantum-plain64?

Hi,

especially for performance reasons, I would like to use Clear Linux on an ex Chromebook which does not support AES-NI. Therefore, I want to use full disk encryption with xchacha12,aes-adiantum-plain64 which has > 4x the speed on this machine (Benchmark in Xubuntu 22.04).

# Algorithm           |       Key |      Encryption |      Decryption
aes-xts                       256b        61.6 MiB/s        62.2 MiB/s
xchacha12,aes-adiantum        256b       264.9 MiB/s       266.0 MiB/s

Unfortunately, the crypto support has not even been included in the kernel and I don’t know about the bootloader. Probably because today’s computers usually have AES support.

Still, would it be possible to use this different encryption somehow? AES is too slow and not using full disk encryption is not sensible on a computer that is only used for travelling.