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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, 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 60DE9C43331 for ; Fri, 6 Sep 2019 19:05:35 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 3B44F207FC for ; Fri, 6 Sep 2019 19:05:35 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3B44F207FC Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:59440 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1i6JY6-0006KM-Fh for qemu-devel@archiver.kernel.org; Fri, 06 Sep 2019 15:05:34 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:40279) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1i6JWP-0005OK-Aq for qemu-devel@nongnu.org; Fri, 06 Sep 2019 15:03:50 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1i6JWO-0007xJ-4b for qemu-devel@nongnu.org; Fri, 06 Sep 2019 15:03:49 -0400 Received: from mx1.redhat.com ([209.132.183.28]:60318) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1i6JWL-0007u1-86; Fri, 06 Sep 2019 15:03:45 -0400 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 56D2F30842B5; Fri, 6 Sep 2019 19:03:44 +0000 (UTC) Received: from maximlenovopc.usersys.redhat.com (unknown [10.35.206.83]) by smtp.corp.redhat.com (Postfix) with ESMTP id 1287F60BF1; Fri, 6 Sep 2019 19:03:41 +0000 (UTC) Message-ID: From: Maxim Levitsky To: Eric Blake , qemu-devel@nongnu.org Date: Fri, 06 Sep 2019 22:03:40 +0300 In-Reply-To: <19dabeca-b99d-822e-84ad-0cc2be90d6c9@redhat.com> References: <20190906173201.7926-1-mlevitsk@redhat.com> <20190906173201.7926-2-mlevitsk@redhat.com> <4dacc6bde5bc87d48f5d3b255a7a44bbded782ef.camel@redhat.com> <19dabeca-b99d-822e-84ad-0cc2be90d6c9@redhat.com> Content-Type: text/plain; charset="UTF-8" Mime-Version: 1.0 Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.40]); Fri, 06 Sep 2019 19:03:44 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.132.183.28 Subject: Re: [Qemu-devel] [PATCH 1/3] block/qcow2: refactoring of threaded encryption code X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Kevin Wolf , Vladimir Sementsov-Ogievskiy , "Daniel P . =?ISO-8859-1?Q?Berrang=E9?=" , qemu-block@nongnu.org, qemu-stable , Max Reitz Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Fri, 2019-09-06 at 14:00 -0500, Eric Blake wrote: > On 9/6/19 1:55 PM, Maxim Levitsky wrote: > > > > > +/* > > > > + * qcow2_co_encrypt() > > > > + * > > > > + * Encrypts a sector size aligned contiguous area > > > > + * > > > > + * @host_cluster_offset - on disk offset of the cluster in which > > > > + * the buffer resides > > > > + * > > > > + * @guest_offset - guest (virtual) offset of the buffer > > > > + * @buf - buffer with the data to encrypt > > > > + * @len - length of the buffer > > > > + * > > > > + * Note that the area is not cluster aligned and might cross a cluster > > > > + * boundary > > > > > > Umm, how is it possible for a sector to cross a cluster boundary? All > > > clusters are sector-aligned, and encryption only works on aligned > > > sectors. Oh, I see - if @len is a multiple larger than sector size, > > > then we have multiple sectors, and then indeed we may cross clusters. > > > But then the docs about being 'a sector size aligned contiguous area' is > > > not quite right. > > > > Why? the written area is always both aligned on _sector_ boundary > > and multiple of the sector size. At least that what I see from > > the existing asserts. > > I'm thinking it should read something like: > > Encrypts one or more contiguous aligned sectors > > to make it obvious that because there can be multiple sectors, there may > indeed be a cluster boundary mid-length. My complaint was that the > original text made it sound like there was exactly one sector (at which > point @len is redundant, unless sectors are variably-sized) > I agree with you completely, I will change that. Best regards, Maxim Levitsky