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 6D3E8C433DB for ; Thu, 31 Dec 2020 10:00:24 +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 DA7C7207A3 for ; Thu, 31 Dec 2020 10:00:23 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org DA7C7207A3 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]:51538 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kuuko-0008OG-NM for qemu-devel@archiver.kernel.org; Thu, 31 Dec 2020 05:00:22 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:35986) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kuuk5-0007pq-Jj; Thu, 31 Dec 2020 04:59:37 -0500 Received: from poy.remlab.net ([2001:41d0:2:5a1a::]:45334 helo=ns207790.ip-94-23-215.eu) by eggs.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kuuk3-0005Xy-To; Thu, 31 Dec 2020 04:59:37 -0500 Received: from philogene.localnet (ip6-localhost [IPv6:::1]) by ns207790.ip-94-23-215.eu (Postfix) with ESMTP id 782565FAD0; Thu, 31 Dec 2020 10:59:34 +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 11:59:34 +0200 Message-ID: <9468010.vzF1F9XyNR@philogene> Organization: Remlab Tmi In-Reply-To: <002743e6-10d3-88b3-961a-8571efb4d1ed@linaro.org> References: <7884934.NyiUUSuA9g@basile.remlab.net> <002743e6-10d3-88b3-961a-8571efb4d1ed@linaro.org> 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, 00:38:14 EET Richard Henderson a =E9crit : > On 12/30/20 2:10 PM, Richard Henderson wrote: > > 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. > >=20 > >> 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 > >> level, > >>=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. >=20 > Having read the next patch, I think you should drop this type change. >=20 > >> @@ -11203,7 +11201,7 @@ static bool get_phys_addr_lpae(CPUARMState *en= v, > >> 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 > This hunk belongs with the next patch, implementing TTST, and should be > conditional. I.e. >=20 > if (stride =3D=3D 9) { > startlevel =3D 2 - sl0; > if (aarch64 && > cpu_isar_feature(aa64_st, env_archcpu(env)) { > startlevel &=3D 3; > } You can do that but: 1) Nothing in the spec says that SL0 =3D=3D b11 without ST means start leve= l -1.=20 It's undefined, and I don't see any reasons to treat it differently than wi= th=20 ST. 2) Functionally, checking for ST seems to belong naturally within=20 check_s2_mmu_setup() in this particular case. > ... >=20 >=20 > r~ =2D-=20 R=E9mi Denis-Courmont