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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2959DC76195 for ; Fri, 24 Mar 2023 08:48:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231817AbjCXIsN (ORCPT ); Fri, 24 Mar 2023 04:48:13 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43864 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231810AbjCXIsK (ORCPT ); Fri, 24 Mar 2023 04:48:10 -0400 Received: from mail-lf1-x12e.google.com (mail-lf1-x12e.google.com [IPv6:2a00:1450:4864:20::12e]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id AD25C6A44; Fri, 24 Mar 2023 01:48:07 -0700 (PDT) Received: by mail-lf1-x12e.google.com with SMTP id i13so1236232lfe.9; Fri, 24 Mar 2023 01:48:07 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; t=1679647686; x=1682239686; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:subject:cc:to:from:date:from:to:cc:subject:date :message-id:reply-to; bh=+CugmSPVEAZOl/CDM7KlMPccXmc+KAo4sr0tOOU2lzo=; b=DzE9VR66YJCpiAMR2ue8DQQZU/WpMFWbYvqlSkzQE2/auGrisKzwzVvwCBHfmHGjat q9RLyui9fhtGIq+qWQvCQdmwDVOW1iK0T7aJtEdyzLoQDDhU49UwKa4+T0wqHpcMMloj BhLiDUwKenTq8OyYrJsr6irE64Y5MCnljKU6b3vN8SmZJE1MjdQcUUmESbl+XtRDt4tj jBqmMvrYxyhvwFq/hzPMCcE99md0r+lFkGSVO5MQmQBDXCMsMcUubIPuhsNekrLubHRT +ajV2bqYZ555AbHHaxEgkxYWhmXe+EfQrRublF/9RRNEudyqXilrkaPsRWBae3ozarhP cVUA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; t=1679647686; x=1682239686; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:subject:cc:to:from:date:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=+CugmSPVEAZOl/CDM7KlMPccXmc+KAo4sr0tOOU2lzo=; b=bLvGzD22WD0k3AUXj6mzlGWu9XdYgdTX1yUUmn6xvDOOpxY9mQYQd49cWq3oKKFp83 7S6Gh9nNM/JZ+gBsi25CM0OJa6lQPgmSK681/4FbUpgrQgYC2r17BhEd5clLC/5RBTkz mYI3RRcIgR3wDr821DjONskTtwe94Kffu2kwuQZ2pBEcOEywU6MOMoVfhiH3P3vLd3T8 slQ0xGlL/yxgRmM4fOilJwWwrEj8+Wcl38U2BJBouQf5lWNUUZmuTZdDQGeg7Qf2uaK1 WyaCfPnvLewoHUVOsorTHsAI8kfmvExJysVrY4hicfGnmRX4loYTj6vn/xpDEge1IdA8 eClA== X-Gm-Message-State: AAQBX9cmzJC15jS4aK3ETljH4L4N1soUYH0j3rv4lcrkH82bzcEeT90C T348zFqto16QCvj98++RWvs= X-Google-Smtp-Source: AKy350YOkO6htfPjqLXF4hqhI4/3CLaSuQiI48ioIvGg6kkEEsMUurmu24YQrCVANbaWmKSxA4Ze5w== X-Received: by 2002:ac2:5fe6:0:b0:4db:3467:f2ff with SMTP id s6-20020ac25fe6000000b004db3467f2ffmr342159lfg.5.1679647685831; Fri, 24 Mar 2023 01:48:05 -0700 (PDT) Received: from localhost (88-115-161-74.elisa-laajakaista.fi. [88.115.161.74]) by smtp.gmail.com with ESMTPSA id g6-20020a19ee06000000b004e9b183fc5bsm2379251lfb.8.2023.03.24.01.48.05 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 24 Mar 2023 01:48:05 -0700 (PDT) Date: Fri, 24 Mar 2023 10:48:03 +0200 From: Zhi Wang To: Sean Christopherson Cc: Pawan Gupta , Paolo Bonzini , kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Nathan Chancellor , Emanuele Giuseppe Esposito , Jim Mattson Subject: Re: [PATCH 5/6] KVM: x86: Virtualize FLUSH_L1D and passthrough MSR_IA32_FLUSH_CMD Message-ID: <20230324104803.000036e9.zhi.wang.linux@gmail.com> In-Reply-To: References: <20230322011440.2195485-1-seanjc@google.com> <20230322011440.2195485-6-seanjc@google.com> <20230323050753.rufixzrzt2sf3avv@desk> X-Mailer: Claws Mail 4.1.0 (GTK 3.24.33; x86_64-w64-mingw32) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 23 Mar 2023 15:17:50 -0700 Sean Christopherson wrote: > On Wed, Mar 22, 2023, Pawan Gupta wrote: > > On Tue, Mar 21, 2023 at 06:14:39PM -0700, Sean Christopherson wrote: > > > diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c > > > index 85bb535fc321..b32edaf5a74b 100644 > > > --- a/arch/x86/kvm/svm/svm.c > > > +++ b/arch/x86/kvm/svm/svm.c > > > @@ -95,6 +95,7 @@ static const struct svm_direct_access_msrs { > > > #endif > > > { .index = MSR_IA32_SPEC_CTRL, .always = false }, > > > { .index = MSR_IA32_PRED_CMD, .always = false }, > > > + { .index = MSR_IA32_FLUSH_CMD, .always = false }, > > > { .index = MSR_IA32_LASTBRANCHFROMIP, .always = false }, > > > { .index = MSR_IA32_LASTBRANCHTOIP, .always = false }, > > > { .index = MSR_IA32_LASTINTFROMIP, .always = false }, > > > @@ -4140,6 +4141,10 @@ static void svm_vcpu_after_set_cpuid(struct kvm_vcpu *vcpu) > > > set_msr_interception(vcpu, svm->msrpm, MSR_IA32_PRED_CMD, 0, > > > !!guest_has_pred_cmd_msr(vcpu)); > > > > > > + if (boot_cpu_has(X86_FEATURE_FLUSH_L1D)) > > > > Just curious, will this ever be true on AMD hardware? AFAIK, > > X86_FEATURE_FLUSH_L1D is Intel-defined CPU feature. > > Don't know myself, but I assume/home there was actual motivation behind adding > support for AMD. Hmm. I took a look on the APM[1] published on Jan 2023, 3.2.9 Speculation control MSRs. It only has SPEC_CTL/PRED_SMD so far. Also, the information here [2] shows this is a mitigation only for Intel CPUs. Looks like AMD does not require this so far. [1] https://www.amd.com/system/files/TechDocs/40332.pdf [2] https://www.kernel.org/doc/html/latest/admin-guide/hw-vuln/l1tf.html