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=-13.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham 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 87B92C433E0 for ; Thu, 31 Dec 2020 09:56:39 +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 D546320786 for ; Thu, 31 Dec 2020 09:56:38 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D546320786 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=remlab.net Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:49072 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kuuhB-0007Bq-VT for qemu-devel@archiver.kernel.org; Thu, 31 Dec 2020 04:56:37 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:35474) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kuugb-0006dW-6o; Thu, 31 Dec 2020 04:56:01 -0500 Received: from poy.remlab.net ([2001:41d0:2:5a1a::]:45296 helo=ns207790.ip-94-23-215.eu) by eggs.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kuugZ-0003rD-4e; Thu, 31 Dec 2020 04:56:00 -0500 Received: from philogene.localnet (ip6-localhost [IPv6:::1]) by ns207790.ip-94-23-215.eu (Postfix) with ESMTP id 211115FAD0; Thu, 31 Dec 2020 10:55:51 +0100 (CET) From: =?ISO-8859-1?Q?R=E9mi?= Denis-Courmont To: qemu-arm@nongnu.org Subject: Re: [PATCH 1/3] target/arm: keep translation start level unsigned Date: Thu, 31 Dec 2020 11:55:50 +0200 Message-ID: <3026104.eZJBrJkB2l@philogene> Organization: Remlab Tmi In-Reply-To: References: <7884934.NyiUUSuA9g@basile.remlab.net> <20201218143321.102872-1-remi.denis.courmont@huawei.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="iso-8859-1" Received-SPF: pass client-ip=2001:41d0:2:5a1a::; envelope-from=remi@remlab.net; helo=ns207790.ip-94-23-215.eu X-Spam_score_int: -18 X-Spam_score: -1.9 X-Spam_bar: - X-Spam_report: (-1.9 / 5.0 requ) BAYES_00=-1.9, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action 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: Richard Henderson , qemu-devel@nongnu.org, remi.denis.courmont@huawei.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Le jeudi 31 d=E9cembre 2020, 00:10:09 EET Richard Henderson a =E9crit : > On 12/18/20 6:33 AM, remi.denis.courmont@huawei.com wrote: > > From: R=E9mi Denis-Courmont > >=20 > > Signed-off-by: R=E9mi Denis-Courmont > > --- > >=20 > > target/arm/helper.c | 14 ++++++-------- > > 1 file changed, 6 insertions(+), 8 deletions(-) >=20 > The patch does more than what is described above. No? It removes generating negative values, and handling them, for translati= on=20 levels. > > diff --git a/target/arm/helper.c b/target/arm/helper.c > > index df195c314c..b927e53ab0 100644 > > --- a/target/arm/helper.c > > +++ b/target/arm/helper.c > >=20 > > @@ -10821,17 +10821,12 @@ do_fault: > > * Returns true if the suggested S2 translation parameters are OK and > > * false otherwise. > > */ > >=20 > > -static bool check_s2_mmu_setup(ARMCPU *cpu, bool is_aa64, int level, > > +static bool check_s2_mmu_setup(ARMCPU *cpu, bool is_aa64, uint32_t lev= el, > >=20 > > int inputsize, int stride) > > =20 > > { > > =20 > > const int grainsize =3D stride + 3; > > int startsizecheck; > >=20 > > - /* Negative levels are never allowed. */ > > - if (level < 0) { > > - return false; > > - } > > - >=20 > I would expect this to be the only hunk from the patch description.=20 > Probably changing this negative check to a >=3D 3 check. You could do that but you'd end up relying on implicity conversion from sig= ned=20 to unsigned negative. That seems needlessly confusing to me in this case,=20 considering that (positive) values larger than 3 cannot actually happen. >=20 > r~ >=20 > > startsizecheck =3D inputsize - ((3 - level) * stride + grainsize); > > if (startsizecheck < 1 || startsizecheck > stride + 4) { > > =20 > > return false; > >=20 > > @@ -10856,6 +10851,9 @@ static bool check_s2_mmu_setup(ARMCPU *cpu, bool > > is_aa64, int level,>=20 > > if (level =3D=3D 0 && pamax <=3D 42) { > > =20 > > return false; > > =20 > > } > >=20 > > + if (level =3D=3D 3) { > > + return false; > > + } > >=20 > > break; > > =20 > > default: > > g_assert_not_reached(); > >=20 > > @@ -10871,7 +10869,7 @@ static bool check_s2_mmu_setup(ARMCPU *cpu, bool > > is_aa64, int level,>=20 > > /* AArch32 only supports 4KB pages. Assert on that. */ > > assert(stride =3D=3D 9); > >=20 > > - if (level =3D=3D 0) { > > + if (level =3D=3D 0 || level >=3D 3) { > >=20 > > return false; > > =20 > > } > > =20 > > } > >=20 > > @@ -11203,7 +11201,7 @@ static bool get_phys_addr_lpae(CPUARMState *env, > > uint64_t address,>=20 > > if (!aarch64 || stride =3D=3D 9) { > > =20 > > /* AArch32 or 4KB pages */ > >=20 > > - startlevel =3D 2 - sl0; > > + startlevel =3D (2 - sl0) & 3; > >=20 > > } else { > > =20 > > /* 16KB or 64KB pages */ > > startlevel =3D 3 - sl0; =2D-=20 R=E9mi Denis-Courmont