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Date:   Tue, 7 Dec 2021 21:29:07 -0800
From:   Jakub Kicinski <kuba@kernel.org>
To:     Herbert Xu <herbert@gondor.apana.org.au>
Cc:     linux-crypto@vger.kernel.org, Sabrina Dubroca <sd@queasysnail.net>
Subject: Re: x86 AES crypto alignment
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In-Reply-To: <20211208044037.GA11399@gondor.apana.org.au>
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On Wed, 8 Dec 2021 15:40:37 +1100 Herbert Xu wrote:
> On Tue, Dec 07, 2021 at 11:32:52AM -0800, Jakub Kicinski wrote:
> > Hi!
> > 
> > The x86 AES crypto (gcm(aes)) requires 16B alignment which is hard to
> > achieve in networking. Is there any reason for this? On any moderately 
> > recent Intel platform aligned and unaligned vmovdq should have the same
> > performance (reportedly).  
> 
> There is no such thing as an alignment requirement.  If an algorithm
> specifies an alignment and you pass it a request which is unaligned,
> the Crypto API will automatically align the data for you.
> 
> So what is the actual problem here?

By align you mean copy right? I'm trying to avoid the copy.