From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id D0EEBC433E0 for ; Sat, 16 Jan 2021 01:44:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8F305212CC for ; Sat, 16 Jan 2021 01:44:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725919AbhAPBoG (ORCPT ); Fri, 15 Jan 2021 20:44:06 -0500 Received: from mail.kernel.org ([198.145.29.99]:35706 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725815AbhAPBoG (ORCPT ); Fri, 15 Jan 2021 20:44:06 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 2D35823120; Sat, 16 Jan 2021 01:43:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1610761406; bh=F5udgBJ6Iub+SVPG8jhyLFZYdMP8H6k/zj+lJZG/UeQ=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=g1Vcmc17LgRbX0P+ycXC1ovEJ5lpf4c/nlmjewMR7/VLLWuWiFyi0KJYrfJ00UoKo Nm4LDuuN20XE39yzrl8BSd6QP+GCc0t6D8cnh27+HOs5R7O4QTyvxaTMm8M1XGXZYr /EVvEfRBxIAS0ACSPLD24yYqdvBglETQub1N7DCrAC/Z8deDUDNs7iJtX8FTAW/dur 4cgRDmp1HhHVybYsMgAt8G135bDHNgjGf2gCvT7VvmA8aqompQ7eV0MI6SX+DQEiAm WmE2FJMLqwcucW06Xz5T+5bSAsGld+XVtQbVKoSC9JcvcJxge75JohQbCW4JGFxYgo MV1wT/ZzCMjKg== Date: Fri, 15 Jan 2021 17:43:23 -0800 From: Eric Biggers To: "Dey, Megha" Cc: Ard Biesheuvel , Herbert Xu , "David S. Miller" , Linux Crypto Mailing List , Linux Kernel Mailing List , ravi.v.shankar@intel.com, tim.c.chen@intel.com, andi.kleen@intel.com, dave.hansen@intel.com, wajdi.k.feghali@intel.com, greg.b.tucker@intel.com, robert.a.kasten@intel.com, rajendrakumar.chinnaiyan@intel.com, tomasz.kantecki@intel.com, ryan.d.saffores@intel.com, ilya.albrekht@intel.com, kyung.min.park@intel.com, Tony Luck , ira.weiny@intel.com Subject: Re: [RFC V1 3/7] crypto: ghash - Optimized GHASH computations Message-ID: References: <1608325864-4033-1-git-send-email-megha.dey@intel.com> <1608325864-4033-4-git-send-email-megha.dey@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-crypto@vger.kernel.org On Fri, Jan 15, 2021 at 04:14:40PM -0800, Dey, Megha wrote: > > Hello Megha, > > > > What is the purpose of this separate GHASH module? GHASH is only used > > in combination with AES-CTR to produce GCM, and this series already > > contains a GCM driver. > > > > Do cores exist that implement PCLMULQDQ but not AES-NI? > > > > If not, I think we should be able to drop this patch (and remove the > > existing PCLMULQDQ GHASH driver as well) > > AFAIK, dm-verity (authenticated but not encrypted file system) is one use > case for authentication only. > > Although I am not sure if GHASH is specifically used for this or SHA? > > Also, I do not know of any cores that implement PCLMULQDQ and not AES-NI. > dm-verity only uses unkeyed hash algorithms. So no, it doesn't use GHASH. - Eric