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 0D44DEB64D9 for ; Tue, 4 Jul 2023 13:46:20 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1qGgLc-0001NQ-N8; Tue, 04 Jul 2023 09:45:40 -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 1qGgLa-0001Mo-GS for qemu-devel@nongnu.org; Tue, 04 Jul 2023 09:45:39 -0400 Received: from mail-wr1-x42a.google.com ([2a00:1450:4864:20::42a]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1qGgLY-0005r0-0u for qemu-devel@nongnu.org; Tue, 04 Jul 2023 09:45:37 -0400 Received: by mail-wr1-x42a.google.com with SMTP id ffacd0b85a97d-3143493728dso2821551f8f.1 for ; Tue, 04 Jul 2023 06:45:35 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; t=1688478334; x=1691070334; h=content-transfer-encoding:mime-version:message-id:in-reply-to:date :subject:cc:to:from:user-agent:references:from:to:cc:subject:date :message-id:reply-to; bh=HjT3mF7VreD2c5HTZpJ7fgCRfd+JAbbocDqAsqZzzKg=; b=rXMDp0vvnAfjgc//glUNH7DFuEISmEer2vwqlQsdweSbduAt2yK+9e1T1boDoangxU y7MOHtlplrx+EoEeKQj+Acthj6DcIMTx7r7JbbV2NDxX2tVEPmfRvlftVyYCbQIJO005 vxMhrOqtP0zNLAHBvihawAtrsMnkwAGZrPk6sG79LxVAkJpipC4as3hsUNLzyUtoGFEC N6uk2JJX2a1u4GbOKctfFzBXN73REkK527fPufeI7OXwjFpO/tiDq9IJfuA4e0YoNBH3 Bx69YKVJZpI9lM52t8IzJpHrpJFXzzeLlBGi30Ir07Va1IB1nNrTs7fCJo8UJNyr50l4 3/5g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1688478334; x=1691070334; h=content-transfer-encoding:mime-version:message-id:in-reply-to:date :subject:cc:to:from:user-agent:references:x-gm-message-state:from:to :cc:subject:date:message-id:reply-to; bh=HjT3mF7VreD2c5HTZpJ7fgCRfd+JAbbocDqAsqZzzKg=; b=gYNV09INJpoNMg/x0FwEK+cmvuCbBaZjIa7nzRY6324Xd/GubyqtQ5dl7SvuH/iCu9 N2v5pRDn3izMq/cLv204Di64d6N/MaF1TwPQfeHBwP9knhqet4AY1rR36m3G5N1NEghE Qv/U+hqVOPrZSLxVfQ3jx6+SOoLFUtmUD/qMmm/uM11PCOvhKekOOAJ/90DjQAvCo8Kk wVKL2Dg6zig3gsZQx7FMdzKzke23blSb4+fgUwt9ZppKNdIAQn9dyEIxCXhf+0+CL5m6 PS9N7OtSiSQS5SPFarI8ZquBqXtST6RPJKGSshskM/YK7H2F9SCHoBxMJvDh5Wc7/LDK evng== X-Gm-Message-State: ABy/qLaYAUkQxBVL2Sl/Qe5c0DAJrxoAjg2zdN0LWb+Dj1ocwKkJycsy eeQJpqwyqnJQjDCG2iqVcdvSmA== X-Google-Smtp-Source: APBJJlHIfUslvfjdqZJks38KTt3+lN2hrNExuteFuHixKfDm7tqnEZudu94Xz5aPTZcchSBeBsH62w== X-Received: by 2002:adf:ea0b:0:b0:314:1a98:ebbb with SMTP id q11-20020adfea0b000000b003141a98ebbbmr12746638wrm.21.1688478334528; Tue, 04 Jul 2023 06:45:34 -0700 (PDT) Received: from zen.linaroharston ([85.9.250.243]) by smtp.gmail.com with ESMTPSA id a15-20020adffacf000000b0031434c08bb7sm6587679wrs.105.2023.07.04.06.45.34 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 04 Jul 2023 06:45:34 -0700 (PDT) Received: from zen (localhost [127.0.0.1]) by zen.linaroharston (Postfix) with ESMTP id A34251FFBB; Tue, 4 Jul 2023 14:45:33 +0100 (BST) References: <20230704130647.2842917-1-peter.maydell@linaro.org> <20230704130647.2842917-2-peter.maydell@linaro.org> User-agent: mu4e 1.11.8; emacs 29.0.92 From: Alex =?utf-8?Q?Benn=C3=A9e?= To: Peter Maydell Cc: qemu-arm@nongnu.org, qemu-devel@nongnu.org Subject: Re: [PATCH 1/2] target/arm: Suppress more TCG unimplemented features in ID registers Date: Tue, 04 Jul 2023 14:45:28 +0100 In-reply-to: <20230704130647.2842917-2-peter.maydell@linaro.org> Message-ID: <87wmzfg58i.fsf@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Received-SPF: pass client-ip=2a00:1450:4864:20::42a; envelope-from=alex.bennee@linaro.org; helo=mail-wr1-x42a.google.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 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, 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 Peter Maydell writes: > We already squash the ID register field for FEAT_SPE (the Statistical > Profiling Extension) because TCG does not implement it and if we > advertise it to the guest the guest will crash trying to look at > non-existent system registers. Do the same for some other features > which a real hardware Neoverse-V1 implements but which TCG doesn't: > * FEAT_TRF (Self-hosted Trace Extension) > * Trace Macrocell system register access > * Memory mapped trace > * FEAT_AMU (Activity Monitors Extension) > * FEAT_MPAM (Memory Partitioning and Monitoring Extension) > * FEAT_NV (Nested Virtualization) > > Most of these, like FEAT_SPE, are "introspection/trace" type features > which QEMU is unlikely to ever implement. The odd-one-out here is > FEAT_NV -- we could implement that and at some point we probably > will. > > Signed-off-by: Peter Maydell Reviewed-by: Alex Benn=C3=A9e --=20 Alex Benn=C3=A9e Virtualisation Tech Lead @ Linaro