Comment # 10 on bug 907692 from grant k

bit more messiness

in the case of

    +ssse3 -aes

i.e.

    cat /proc/cpuinfo | grep flag
        flags           : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge
mca cmov pat pse36 clflush dts acpi mmx fxsr serf pni dtes64 monitor ds_cpl vmx
est tm2 ssse3 cx16 xtpr pdcm pcid sse4_1 sse4_2 popcnt lahf_lm arat dtherm
tpr_shad

on boot, where

    cat /etc/modprobe.d/99-crypto.conf 
        alias aes aes_x86_64

boot log returns

    journalctl -b | grep aes
        Nov 30 11:12:31 laptop017 dracut-pre-udev[224]: modprobe: ERROR: could
not find module by name='aes_x86_64'
        Nov 30 11:12:31 laptop017 dracut-pre-udev[224]: modprobe: ERROR: could
not insert 'aes_x86_64': Function not implemented

at shell

    lsmod | grep aes
        (empty)

but

    modprobe aes
    lsmod | grep aes
        aes_x86_64             17131  0 

works fine

adding

    /etc/sysconfig/kernel
        INITRD_MODULES="... aes_x86_64 ..."

then

    mkinitrd
    reboot

once booted

    journalctl -b | grep aes
    lsmod | grep aes
        aes_x86_64             17131  0 

atm, I'm unclear/inconsistent how to prepare & boot a LUKS-ready initrd without
manual intervention