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From:   Ard Biesheuvel <ardb@kernel.org>
Date:   Wed, 29 Jul 2020 09:06:53 +0300
Message-ID: <CAMj1kXFwPPDfm1hvW+LgnfuPO-wfguTZ0NcLyeyesGeBcuDKGQ@mail.gmail.com>
Subject: Re: Help getting aesni crypto patch upstream
To:     Ben Greear <greearb@candelatech.com>
Cc:     Linux Crypto Mailing List <linux-crypto@vger.kernel.org>
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On Wed, 29 Jul 2020 at 01:03, Ben Greear <greearb@candelatech.com> wrote:
>
> Hello,
>
> As part of my wifi test tool, I need to do decrypt AES on the CPU, and the only way this
> performs well is to use aesni.  I've been using a patch for years that does this, but
> recently somewhere between 5.4 and 5.7, the API I've been using has been removed.
>
> Would anyone be interested in getting this support upstream?  I'd be happy to pay for
> the effort.
>
> Here is the patch in question:
>
> https://github.com/greearb/linux-ct-5.7/blob/master/wip/0001-crypto-aesni-add-ccm-aes-algorithm-implementation.patch
>
> Please keep me in CC, I'm not subscribed to this list.
>

Hi Ben,

Recently, the x86 FPU handling was improved to remove the overhead of
preserving/restoring of the register state, so the issue that this
patch fixes may no longer exist. Did you try?

In any case, according to the commit log on that patch, the problem is
in the MAC generation, so it might be better to add a cbcmac(aes)
implementation only, and not duplicate all the CCM boilerplate.