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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4163BC64EC4 for ; Mon, 6 Mar 2023 21:16:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229744AbjCFVQb (ORCPT ); Mon, 6 Mar 2023 16:16:31 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39416 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229715AbjCFVQ3 (ORCPT ); Mon, 6 Mar 2023 16:16:29 -0500 Received: from mail-pl1-x649.google.com (mail-pl1-x649.google.com [IPv6:2607:f8b0:4864:20::649]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D1D97515F9 for ; Mon, 6 Mar 2023 13:16:26 -0800 (PST) Received: by mail-pl1-x649.google.com with SMTP id k17-20020a170902d59100b0019abcf45d75so6406279plh.8 for ; Mon, 06 Mar 2023 13:16:26 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; t=1678137386; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=4cSjs2hF+stLMorZuJ3Q4yg6wn5aTQLGNhdQrvetiCw=; b=nO81Dd+ZdOpPz+rMZF+TlStTUcOdB9fYf13b12+wmj6L3uW+fQA7rdl9b7YXUwV0jX I13woF73Otxijbj8ERXL0Ue7ErTR+09OxofYhExYX82U38pFRLv7VwAAVLlkCf8njVEy Z/kRmWywNVghsM99HWEY5cKmP9X1L+vYcJn9Gu5g39MFFMOh6J/04/U2GjXKa8nzeKgt VXWrXIyQkhG/rNkxiRYiCvs89f/6XCE73rAe2CCcH2mdABft17Q0wfBOkrN9i7G7XGV9 qMRC7I0Cn3xahUbo9C0V4E1U0nKdC9XcIy+nSLME4DyqC6ubKOlchC87aSk/WleNGZN1 Vi9Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; t=1678137386; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=4cSjs2hF+stLMorZuJ3Q4yg6wn5aTQLGNhdQrvetiCw=; b=iPHrnRj5UCyeKyDA+VadUjcDDp/WSqTW1N5lBGyS747fdDIkxin/z5UZM4+cUr9cGp 7ebF6pIWRKaz7b4cSOgJFaeECKjU5qzb+/1l8cDeVqEs+im1o3Okms8KYNIWMAT+iWbm rMhG6KfOKSQO10Ma6jueNVJo1R1RNt61kt5Ot3DMKPcBTqqjZcdN5an2j3jjWZ8CDnam rK8xDq1oFzCB2xD8YSPkaMQx5AZmOAvOGk977dVNBWdt7BM5XC7gc39Zs6Gv6P/BRFxk Z/xek8w5lT5MLLDxT3JPokOe6xKKroVCGJT15CCwE0vBryKpqyOyAH0xaGE6XVTqDkuJ VPZA== X-Gm-Message-State: AO0yUKWY2N7g7krAnkFwXJIA7lBmbQ5SsqRaaHP/QqAJWbCezzX/PgPJ aWA5WNDA9BT+M6B/+cmUWMJu7ZtQq5w= X-Google-Smtp-Source: AK7set/FdOs8fBG1Qf4JZnE/q2KTXSkvw2Xh3WHAVa7wzG+qH5k8o2Dr60lo7nSbCYK7xaiiauyALjwZOQ8= X-Received: from zagreus.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:5c37]) (user=seanjc job=sendgmr) by 2002:a62:d443:0:b0:5df:9809:6220 with SMTP id u3-20020a62d443000000b005df98096220mr5102359pfl.3.1678137386366; Mon, 06 Mar 2023 13:16:26 -0800 (PST) Date: Mon, 6 Mar 2023 13:16:25 -0800 In-Reply-To: Mime-Version: 1.0 References: <20230228222416.61484-1-itazur@amazon.com> Message-ID: Subject: Re: [PATCH 0/2] KVM: x86: Propagate AMD-specific IBRS bits to guests From: Sean Christopherson To: Borislav Petkov Cc: Takahiro Itazuri , dave.hansen@linux.intel.com, kvm@vger.kernel.org, linux-kernel@vger.kernel.org, mingo@redhat.com, pbonzini@redhat.com, tglx@linutronix.de, x86@kernel.org, zulinx86@gmail.com Content-Type: text/plain; charset="us-ascii" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Feb 28, 2023, Borislav Petkov wrote: > On Tue, Feb 28, 2023 at 10:24:16PM +0000, Takahiro Itazuri wrote: > > I'm still a kernel newbie and I don't have a strong opinion for that. > > I just thought it would be helpful if the KVM_GET_SUPPORTED_CPUID API > > returns the same security information as the host, as long as it is > > harmless. > > Not harmless - cpufeatures.h should contain flags which the kernel uses > and not *every* CPUID bit out there. I thought that the consensus was that adding unused-by-the-kernel flags to cpufeatures.h is ok so long as the feature is hidden from /proc/cpuinfo and the kernel already dedicates a word to the CPUID leaf?