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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id 3561CEB64DC for ; Wed, 19 Jul 2023 01:16:38 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1qLvnS-0000B1-Av; Tue, 18 Jul 2023 21:16:06 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1qLvnQ-00009m-Qe; Tue, 18 Jul 2023 21:16:04 -0400 Received: from mail-vk1-xa30.google.com ([2607:f8b0:4864:20::a30]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1qLvnP-0007X7-8Q; Tue, 18 Jul 2023 21:16:04 -0400 Received: by mail-vk1-xa30.google.com with SMTP id 71dfb90a1353d-460eb67244eso2227402e0c.1; Tue, 18 Jul 2023 18:16:02 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20221208; t=1689729362; x=1692321362; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:from:to:cc:subject:date :message-id:reply-to; bh=sSZSwo9AXZtyg5OowIjoeQJ9mq2RMX+zs8VLQ0DNTlw=; b=QRIjDRbOXrEbHb1c4fEweg8iWn9YG1jvMvLIQPyKDMpUmOkNy0ib8bJJzoQUCn0oh7 kEVS0+UQiPRDYhccWfLKGdrR0Jg+QUf2NiQBnW0yEDntcMWSPccLQ+4H3M6uI2ifDo7A bmFwkOL7ZuY1i2NEqVPtv/9d4z8ZqDymRFKJpcU59Y2XsY1mUs4JAgOJCpLXfSX06CRb yfyV5XkKctRpwYlDjAfIGWXRt7RhGva0Hb7jVjQepm84sVxkIkMZyJQvkHEFfpemTxzP zWKhQfK9Z50S8/+6LdZptkMJkOQj+KnkkthKkK07CswwtMPpAwfmGa8yWIZ+y0Zkf/y/ Gv0A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1689729362; x=1692321362; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=sSZSwo9AXZtyg5OowIjoeQJ9mq2RMX+zs8VLQ0DNTlw=; b=ilsgVLo1m1isjgpMRnmvmt89NgX6gNEJPV1d3zsemRcBJoKYovrVgDaHcIjRkkEqEn Na2EwnyqKkaeRkpmc/slFAfS/g4b+BBx13+rjFV87Uz5dqiWH9FkGfeRsszLNmUBJBau BXDB959ZRNEqE3zifsrbnyiQ5N+dygHC9MADtq3cVWCawuEIAT7Xurq3N/0x0BiJgH3X DNmjuTfhmG8lDUJDH3uTHVz8ENzl4Ohv5StQKRURTqRZH7SNLz/IeaRFPwGL9zBrGq0R qW0sSe8Jlm+IOFByBgPymEAAJRTw2uIYOVfvyj/73g1CwnrU8DR+dbFCZovcjtVsZPOU AVRw== X-Gm-Message-State: ABy/qLbyYtUg7p547r/aaydIbJORlUYV2jkdRzL06wblGc4rO31PvpyD A2F1C2qEUJWp4yCkkfKGLJ4Xf+d7UA0AUjtgzEo= X-Google-Smtp-Source: APBJJlFPl5LY5GgHY4ueb2d6bo47aTu4lfv8JUaspW+rQDR0pprpPtZXfDWc1JnsgxGXdOsNBxq5g7rrjHjxv28/rFg= X-Received: by 2002:a1f:5f0b:0:b0:481:2ff5:c9b2 with SMTP id t11-20020a1f5f0b000000b004812ff5c9b2mr943024vkb.5.1689729361833; Tue, 18 Jul 2023 18:16:01 -0700 (PDT) MIME-Version: 1.0 References: <20230717154141.60898-1-dbarboza@ventanamicro.com> In-Reply-To: <20230717154141.60898-1-dbarboza@ventanamicro.com> From: Alistair Francis Date: Wed, 19 Jul 2023 11:15:35 +1000 Message-ID: Subject: Re: [PATCH] target/riscv/cpu.c: check priv_ver before auto-enable zca/zcd/zcf To: Daniel Henrique Barboza Cc: qemu-devel@nongnu.org, qemu-riscv@nongnu.org, alistair.francis@wdc.com, bmeng@tinylab.org, liweiwei@iscas.ac.cn, zhiwei_liu@linux.alibaba.com, palmer@rivosinc.com, Conor Dooley Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Received-SPF: pass client-ip=2607:f8b0:4864:20::a30; envelope-from=alistair23@gmail.com; helo=mail-vk1-xa30.google.com 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, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, FREEMAIL_ENVFROM_END_DIGIT=0.25, FREEMAIL_FROM=0.001, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On Tue, Jul 18, 2023 at 1:42=E2=80=AFAM Daniel Henrique Barboza wrote: > > Commit bd30559568 made changes in how we're checking and disabling > extensions based on env->priv_ver. One of the changes was to move the > extension disablement code to the end of realize(), being able to > disable extensions after we've auto-enabled some of them. > > An unfortunate side effect of this change started to happen with CPUs > that has an older priv version, like sifive-u54. Starting on commit > 2288a5ce43e5 we're auto-enabling zca, zcd and zcf if RVC is enabled, > but these extensions are priv version 1.12.0. When running a cpu that > has an older priv ver (like sifive-u54) the user is spammed with > warnings like these: > > qemu-system-riscv64: warning: disabling zca extension for hart 0x00000000= 00000000 because privilege spec version does not match > qemu-system-riscv64: warning: disabling zcd extension for hart 0x00000000= 00000000 because privilege spec version does not match > > The warnings are part of the code that disables the extension, but in thi= s > case we're throwing user warnings for stuff that we enabled on our own, > without user intervention. Users are left wondering what they did wrong. > > A quick 8.1 fix for this nuisance is to check the CPU priv spec before > auto-enabling zca/zcd/zcf. A more appropriate fix will include a more > robust framework that will account for both priv_ver and user choice > when auto-enabling/disabling extensions, but for 8.1 we'll make it do > with this simple check. > > It's also worth noticing that this is the only case where we're > auto-enabling extensions based on a criteria (in this case RVC) that > doesn't match the priv spec of the extensions we're enabling. There's no > need for more 8.1 band-aids. > > Cc: Conor Dooley > Fixes: 2288a5ce43e5 ("target/riscv: add cfg properties for Zc* extension"= ) > Signed-off-by: Daniel Henrique Barboza Thanks! Applied to riscv-to-apply.next Alistair > --- > target/riscv/cpu.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/target/riscv/cpu.c b/target/riscv/cpu.c > index 9339c0241d..6b93b04453 100644 > --- a/target/riscv/cpu.c > +++ b/target/riscv/cpu.c > @@ -1225,7 +1225,8 @@ void riscv_cpu_validate_set_extensions(RISCVCPU *cp= u, Error **errp) > } > } > > - if (riscv_has_ext(env, RVC)) { > + /* zca, zcd and zcf has a PRIV 1.12.0 restriction */ > + if (riscv_has_ext(env, RVC) && env->priv_ver >=3D PRIV_VERSION_1_12_= 0) { > cpu->cfg.ext_zca =3D true; > if (riscv_has_ext(env, RVF) && env->misa_mxl_max =3D=3D MXL_RV32= ) { > cpu->cfg.ext_zcf =3D true; > -- > 2.41.0 > >