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=-14.4 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_IN_DEF_DKIM_WL 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 8EAEAC76188 for ; Mon, 22 Jul 2019 14:51:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 583C52190F for ; Mon, 22 Jul 2019 14:51:14 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="IcEx/SXt" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726467AbfGVOvN (ORCPT ); Mon, 22 Jul 2019 10:51:13 -0400 Received: from mail-lj1-f195.google.com ([209.85.208.195]:46011 "EHLO mail-lj1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726084AbfGVOvN (ORCPT ); Mon, 22 Jul 2019 10:51:13 -0400 Received: by mail-lj1-f195.google.com with SMTP id m23so37823994lje.12 for ; Mon, 22 Jul 2019 07:51:12 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to; bh=NmRF2kaOw40rznWfjCJVbDC4AKTC36kv0HPXnc5ddCE=; b=IcEx/SXtNd4jWKbyW4aH7+REj3HlGulQ0ynWwdqqpmDj81tKnzrPGxonAKrC41cDu1 lIjkyi3Imh05LQD/0cMlmohlgwjz4mmgtxrAXd/QqKUVBlntJJPFyJ5Ykqts8SbYemwy r+CNet9lKScw3W0R5gJRlOD5ElE90Kbh9xzctfXfi2JKlC7PQwx6AZ+Y0JXHfCoPai5D OCjg7Cy09oD4gFtU6yJdcp/l7DZ2MElTIEl120681RvM8SskJ+G/AXESTDhV07phceK6 7lNJbPV2nP3usZ48j9i5lU/z55NVR7d5jaFMh5OD1NMgokaPXTC6aOD5zu4Uv9tFSz+3 sZpg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to; bh=NmRF2kaOw40rznWfjCJVbDC4AKTC36kv0HPXnc5ddCE=; b=gTKVRHvl+R1HiIRM2aITyeuerd9tWirhFsIVQrqycTgP5oV0FojcsSshpnuHkjSTxs BxgaHuPJGqg8dVvmRTtEoBR2ruYyJg/MQnngJ6G34QBOGea/YJ9sOHCRVBcBdfpN0T5S hco57Sr9HaezPklx6ZnXDR1/UHnOBQosCqKhLpg9YbUHZi3nTafE7bbIg/z1FZxdSJgT XnnBOW70H7e1Wy0V1VE+za0/u+46WqKFseaQMUOBcuPZEceP9z3k0vFxQvknS1WXrw+R jsRw4HYh1iQOj6d8OR7HIjpGDBeghMhxBJbQgFisOApEltrBYcMmhW2TWuM2elgviGCi 5OSw== X-Gm-Message-State: APjAAAVHuIHN/wus9sYAoGJ6rCGT0pKwjvCtzlDWddhK9XJeqw2+sprg lsu9Rx4hPwr9Ahoo3GR4se6R5kM25T1TtaGarb2AdQ== X-Google-Smtp-Source: APXvYqz6JRfNu2bVHEI+xCIwQ7lkO4Ojm0nd94T2byHbDrkwkxd9qY8dFLL8/8bRVKt2iVlrg/oo/r8WhE7XeaCxwxc= X-Received: by 2002:a2e:8945:: with SMTP id b5mr35716701ljk.93.1563807071622; Mon, 22 Jul 2019 07:51:11 -0700 (PDT) MIME-Version: 1.0 References: <20190715210316.25569-1-aaronlewis@google.com> In-Reply-To: <20190715210316.25569-1-aaronlewis@google.com> From: Aaron Lewis Date: Mon, 22 Jul 2019 07:51:00 -0700 Message-ID: Subject: Re: [PATCH] KVM: CPUID: Add new features to the guest's CPUID To: Jim Mattson , kvm@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On Mon, Jul 15, 2019 at 2:03 PM Aaron Lewis wrote: > > Add features X86_FEATURE_FDP_EXCPTN_ONLY and X86_FEATURE_ZERO_FCS_FDS to the > mask for CPUID.(EAX=07H,ECX=0H):EBX. Doing this will ensure the guest's CPUID > for these bits match the host, rather than the guest being blindly set to 0. > > This is important as these are actually defeature bits, which means that > a 0 indicates the presence of a feature and a 1 indicates the absence of > a feature. since these features cannot be emulated, kvm should not > claim the existence of a feature that isn't present on the host. > > Signed-off-by: Aaron Lewis > --- > arch/x86/kvm/cpuid.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c > index ead681210306..64c3fad068e1 100644 > --- a/arch/x86/kvm/cpuid.c > +++ b/arch/x86/kvm/cpuid.c > @@ -353,7 +353,8 @@ static inline void do_cpuid_7_mask(struct kvm_cpuid_entry2 *entry, int index) > F(BMI2) | F(ERMS) | f_invpcid | F(RTM) | f_mpx | F(RDSEED) | > F(ADX) | F(SMAP) | F(AVX512IFMA) | F(AVX512F) | F(AVX512PF) | > F(AVX512ER) | F(AVX512CD) | F(CLFLUSHOPT) | F(CLWB) | F(AVX512DQ) | > - F(SHA_NI) | F(AVX512BW) | F(AVX512VL) | f_intel_pt; > + F(SHA_NI) | F(AVX512BW) | F(AVX512VL) | f_intel_pt | > + F(FDP_EXCPTN_ONLY) | F(ZERO_FCS_FDS); > > /* cpuid 7.0.ecx*/ > const u32 kvm_cpuid_7_0_ecx_x86_features = > -- > 2.22.0.510.g264f2c817a-goog > ping