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=-3.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_NEOMUTT autolearn=unavailable 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 6BA9FC28CC3 for ; Thu, 30 May 2019 13:26:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4113623B6B for ; Thu, 30 May 2019 13:26:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726998AbfE3N0c (ORCPT ); Thu, 30 May 2019 09:26:32 -0400 Received: from helcar.hmeau.com ([216.24.177.18]:37858 "EHLO deadmen.hmeau.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726673AbfE3N0c (ORCPT ); Thu, 30 May 2019 09:26:32 -0400 Received: from gondobar.mordor.me.apana.org.au ([192.168.128.4] helo=gondobar) by deadmen.hmeau.com with esmtps (Exim 4.89 #2 (Debian)) id 1hWL4d-0005CI-N1; Thu, 30 May 2019 21:26:27 +0800 Received: from herbert by gondobar with local (Exim 4.89) (envelope-from ) id 1hWL4Z-0003Xt-Fa; Thu, 30 May 2019 21:26:23 +0800 Date: Thu, 30 May 2019 21:26:23 +0800 From: Herbert Xu To: Horia Geanta Cc: Ard Biesheuvel , Eric Biggers , Iuliana Prodan , "David S. Miller" , Sascha Hauer , "linux-crypto@vger.kernel.org" , "linux-kernel@vger.kernel.org" , dl-linux-imx Subject: Re: [PATCH] crypto: gcm - fix cacheline sharing Message-ID: <20190530132623.4h3y2bymv4uvfnms@gondor.apana.org.au> References: <1559149856-7938-1-git-send-email-iuliana.prodan@nxp.com> <20190529202728.GA35103@gmail.com> <20190530053421.keesqb54yu5w7hgk@gondor.apana.org.au> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: NeoMutt/20170113 (1.7.2) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, May 30, 2019 at 01:18:34PM +0000, Horia Geanta wrote: > > I guess there are only two options: > -either cache line sharing is avoided OR > -users need to be *aware* they are sharing the cache line and some rules / > assumptions are in place on how to safely work on the data No there is a third option and it's very simple: You must only access the virtual addresses given to you before DMA mapping or after DMA unmapping. Cheers, -- Email: Herbert Xu Home Page: http://gondor.apana.org.au/~herbert/ PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt