From: Herbert Xu <herbert@gondor.apana.org.au>
To: Eric Biggers <ebiggers@kernel.org>
Cc: linux-crypto@vger.kernel.org, x86@kernel.org
Subject: Re: [PATCH] crypto: x86/aes-gcm - simplify GCM hash subkey derivation
Date: Fri, 26 Apr 2024 17:39:19 +0800 [thread overview]
Message-ID: <Zit2R6Ju7UvAiuwS@gondor.apana.org.au> (raw)
In-Reply-To: <20240420181942.GA786@quark.localdomain>
Eric Biggers <ebiggers@kernel.org> wrote:
> On Fri, Apr 19, 2024 at 11:00:37PM -0700, Eric Biggers wrote:
>> + aes_encrypt(aes_key, hash_subkey, page_address(ZERO_PAGE(0)));
>
> Actually, page_address(ZERO_PAGE(0)) expands into a surprisingly large number of
> instructions. Using empty_zero_page directly would avoid this, but there's
> little precedent for doing that. For now, I think just using something like
> 'static const u8 zeroes[16]' is the way to go for small buffers like this.
Yes it's not worth the effort given the small size. But still it
looks like lib/raid6 could benefit from using a shared zero page
too.
Cheers,
--
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
prev parent reply other threads:[~2024-04-26 9:39 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-04-20 6:00 [PATCH] crypto: x86/aes-gcm - simplify GCM hash subkey derivation Eric Biggers
2024-04-20 18:19 ` Eric Biggers
2024-04-26 9:39 ` Herbert Xu [this message]
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