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Subject: Re: Help getting aesni crypto patch upstream
To:     Ard Biesheuvel <ardb@kernel.org>
Cc:     Linux Crypto Mailing List <linux-crypto@vger.kernel.org>
References: <2a55b661-512b-9479-9fff-0f2e2a581765@candelatech.com>
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 <CAMj1kXFK4xkieEpjW+ekYf9am6Ob15aGsnmWJMfn=LD_4oCuXg@mail.gmail.com>
From:   Ben Greear <greearb@candelatech.com>
Organization: Candela Technologies
Message-ID: <9e6927a6-8f70-009a-ad76-4f11a396e43a@candelatech.com>
Date:   Wed, 29 Jul 2020 12:29:23 -0700
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On 7/29/20 12:09 PM, Ard Biesheuvel wrote:
> On Wed, 29 Jul 2020 at 15:27, Ben Greear <greearb@candelatech.com> wrote:
>>
>> On 7/28/20 11:06 PM, Ard Biesheuvel wrote:
>>> 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.
>>>
>>
>> Hello,
>>
>> I don't know all of the details, and do not understand the crypto subsystem,
>> but I am pretty sure that I need at least some of this patch.
>>
> 
> Whether this is true is what I am trying to get clarified.
> 
> Your patch works around a performance bottleneck related to the use of
> AES-NI instructions in the kernel, which has been addressed recently.
> If the issue still exists, we can attempt to devise a fix for it,
> which may or may not be based on this patch.

Ok, I can do the testing.  Do you expect 5.7-stable has all the needed
performance improvements?

Thanks,
Ben

> 
>> If you can suggest a patch to try I'll be happy to test it to see how it
>> performs.
>>
> 
> Please share performance numbers of an old kernel with this patch
> applied, and a recent one without. If that shows there is in fact an
> issue, we will do something about it.
> 
>>
>> --
>> Ben Greear <greearb@candelatech.com>
>> Candela Technologies Inc  http://www.candelatech.com
> 


-- 
Ben Greear <greearb@candelatech.com>
Candela Technologies Inc  http://www.candelatech.com