2009-04-30 19:27:07

by David Lamparter

[permalink] [raw]
Subject: XTS cipher mode not using assembler AES implementation?

Hello linux-crypto list,

I beg pardon for bothering you with this, but I'm slightly irritated
by /proc/crypto output on my box. It lists:

name : xts(aes)
driver : xts(aes-generic)
module : kernel
priority : 100
refcnt : 2
name : aes
driver : aes-generic
module : kernel
priority : 100
refcnt : 4
name : aes
driver : aes-asm
module : kernel
priority : 200
refcnt : 1

[no xts(aes-asm) entry]

So, basically, my dm-crypt (cipher: aes-xts-essiv:wp256) uses the
generic AES implementation if I'm reading this right? What do I need to
do to get it to use the aes-asm one?

(In case it matters, I have the crypto stuff compiled into the kernel
because my rootfs is on crypto, so I'm just booting a kernel with
everything needed compiled in for ease of setup... maybe xts initializes
before aes-asm does?)

Thankful for any information, please Cc me as I'm not subscribed on

David Lamparter

(# uname -a
Linux jupiter #1 SMP Tue Mar 3 18:05:40
CET 2009 x86_64 AMD Athlon(tm) Dual Core Processor 4450e AuthenticAMD
# gunzip -c /proc/config.gz | pcregrep '_AES|_XTS'

crypto device performance is 35 MB/s, underlying device does 200 MB/s)