From nobody Sun Feb 8 17:43:03 2026 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 8E48BC0015E for ; Sat, 29 Jul 2023 01:18:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237422AbjG2BSX (ORCPT ); Fri, 28 Jul 2023 21:18:23 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36430 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237506AbjG2BRi (ORCPT ); Fri, 28 Jul 2023 21:17:38 -0400 Received: from mail-pl1-x64a.google.com (mail-pl1-x64a.google.com [IPv6:2607:f8b0:4864:20::64a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D570A49EA for ; Fri, 28 Jul 2023 18:17:07 -0700 (PDT) Received: by mail-pl1-x64a.google.com with SMTP id d9443c01a7336-1bbb97d27d6so18432715ad.1 for ; Fri, 28 Jul 2023 18:17:07 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20221208; t=1690593401; x=1691198201; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:reply-to:from:to:cc:subject:date:message-id:reply-to; bh=Y8epFYKyce1KnScIbSRkcuIoi0XcTk6uaJkGq1C7BJM=; b=qZgEyJuxgzUpwGX2Mn+ohO2gYTQrmIw0kdGVMzx6haVus/h7RD1MI1VGtBEFEHyods dpurSEpGuzO0+gcSy8R6KUUKSgxU1c1CEgrODN84DsDzj2p4BM2Wv6MIVfXD5J9lGm69 1fcXmrsVSrrxrfbrFS4lE5kHMfuwy55o2mN3jXqZJGxKIaXcodeTBE/6HFpJqc3V/7V7 64ZqHVnt3hcMlS9oC3pKNmiwQlIdXlyd3zPwuWPTY0EIYgdHG+uQfio4L5wX7E0jQEs8 A1Tnj/JKAWdTMSW9CsItz6c0/UYcuekd7XgvE+c8OSu0aGIRRBG4Mfve+VuuGYV8pvv7 ++xA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1690593401; x=1691198201; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:reply-to:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=Y8epFYKyce1KnScIbSRkcuIoi0XcTk6uaJkGq1C7BJM=; b=XLI5+QSPdBMtnl4YvYDeitFbxgQ9lzaamfMR1OncIddMsWt9AajVQYJXpw5TzHg+Ah sjzp7KZ2VdhO6c+9qxf2bfyyZAUvSO2QIy1fUIaFCvUyEy5aE8NPPC6yd6Cw/LxlIuC6 rYx1VPo2RBC0zWIffJCRDFoS7+Gj9KRWmoyopJfxBgprLafOccNGUIdq0W8Osb5nZ675 m+/jZiF++STW+41tlLN6atySc/tLBbAbX2G+CuMw2ef9hRW/W+OGqqEzo+QWANfXuwCG w5pqNWuLL0bNJYSEdUn+P0J4rHS+UjZMt/8ht1jZ1DChJ5XzytFqeQDnzZQgCKa2GYjC CA8g== X-Gm-Message-State: ABy/qLZsbKwipmtXV/gu1fQOVxYUA8YszEnntJ7S9r6vf326Aogr7rG0 JEAlafs84KSSrIPtbpsNT7ZF0mFcvk8= X-Google-Smtp-Source: APBJJlEdj76n8IZm16b86VgVQmKE54SzKyigxPMKB+s7rxNWA+iel+HMTj+S9/jMvC/DRMAS9a6kHHLGAPI= X-Received: from zagreus.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:5c37]) (user=seanjc job=sendgmr) by 2002:a17:903:2445:b0:1bb:c7bc:ce9a with SMTP id l5-20020a170903244500b001bbc7bcce9amr13662pls.10.1690593401752; Fri, 28 Jul 2023 18:16:41 -0700 (PDT) Reply-To: Sean Christopherson Date: Fri, 28 Jul 2023 18:16:02 -0700 In-Reply-To: <20230729011608.1065019-1-seanjc@google.com> Mime-Version: 1.0 References: <20230729011608.1065019-1-seanjc@google.com> X-Mailer: git-send-email 2.41.0.487.g6d72f3e995-goog Message-ID: <20230729011608.1065019-16-seanjc@google.com> Subject: [PATCH v2 15/21] KVM: nSVM: Use KVM-governed feature framework to track "TSC scaling enabled" From: Sean Christopherson To: Sean Christopherson , Paolo Bonzini , Vitaly Kuznetsov Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Maxim Levitsky Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Track "TSC scaling exposed to L1" via a governed feature flag instead of using a dedicated bit/flag in vcpu_svm. Note, this fixes a benign bug where KVM would mark TSC scaling as exposed to L1 even if overall nested SVM supported is disabled, i.e. KVM would let L1 write MSR_AMD64_TSC_RATIO even when KVM didn't advertise TSCRATEMSR support to userspace. Signed-off-by: Sean Christopherson --- arch/x86/kvm/governed_features.h | 1 + arch/x86/kvm/svm/nested.c | 2 +- arch/x86/kvm/svm/svm.c | 10 ++++++---- arch/x86/kvm/svm/svm.h | 1 - 4 files changed, 8 insertions(+), 6 deletions(-) diff --git a/arch/x86/kvm/governed_features.h b/arch/x86/kvm/governed_featu= res.h index 722b66af412c..32c0469cf952 100644 --- a/arch/x86/kvm/governed_features.h +++ b/arch/x86/kvm/governed_features.h @@ -9,6 +9,7 @@ KVM_GOVERNED_X86_FEATURE(GBPAGES) KVM_GOVERNED_X86_FEATURE(XSAVES) KVM_GOVERNED_X86_FEATURE(VMX) KVM_GOVERNED_X86_FEATURE(NRIPS) +KVM_GOVERNED_X86_FEATURE(TSCRATEMSR) =20 #undef KVM_GOVERNED_X86_FEATURE #undef KVM_GOVERNED_FEATURE diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c index 9092f3f8dccf..da65948064dc 100644 --- a/arch/x86/kvm/svm/nested.c +++ b/arch/x86/kvm/svm/nested.c @@ -695,7 +695,7 @@ static void nested_vmcb02_prepare_control(struct vcpu_s= vm *svm, =20 vmcb02->control.tsc_offset =3D vcpu->arch.tsc_offset; =20 - if (svm->tsc_scaling_enabled && + if (guest_can_use(vcpu, X86_FEATURE_TSCRATEMSR) && svm->tsc_ratio_msr !=3D kvm_caps.default_tsc_scaling_ratio) nested_svm_update_tsc_ratio_msr(vcpu); =20 diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c index 7c1aa532f767..2f7f7df5a591 100644 --- a/arch/x86/kvm/svm/svm.c +++ b/arch/x86/kvm/svm/svm.c @@ -2755,7 +2755,8 @@ static int svm_get_msr(struct kvm_vcpu *vcpu, struct = msr_data *msr_info) =20 switch (msr_info->index) { case MSR_AMD64_TSC_RATIO: - if (!msr_info->host_initiated && !svm->tsc_scaling_enabled) + if (!msr_info->host_initiated && + !guest_can_use(vcpu, X86_FEATURE_TSCRATEMSR)) return 1; msr_info->data =3D svm->tsc_ratio_msr; break; @@ -2897,7 +2898,7 @@ static int svm_set_msr(struct kvm_vcpu *vcpu, struct = msr_data *msr) switch (ecx) { case MSR_AMD64_TSC_RATIO: =20 - if (!svm->tsc_scaling_enabled) { + if (!guest_can_use(vcpu, X86_FEATURE_TSCRATEMSR)) { =20 if (!msr->host_initiated) return 1; @@ -2919,7 +2920,8 @@ static int svm_set_msr(struct kvm_vcpu *vcpu, struct = msr_data *msr) =20 svm->tsc_ratio_msr =3D data; =20 - if (svm->tsc_scaling_enabled && is_guest_mode(vcpu)) + if (guest_can_use(vcpu, X86_FEATURE_TSCRATEMSR) && + is_guest_mode(vcpu)) nested_svm_update_tsc_ratio_msr(vcpu); =20 break; @@ -4220,8 +4222,8 @@ static void svm_vcpu_after_set_cpuid(struct kvm_vcpu = *vcpu) kvm_governed_feature_set(vcpu, X86_FEATURE_XSAVES); =20 kvm_governed_feature_check_and_set(vcpu, X86_FEATURE_NRIPS); + kvm_governed_feature_check_and_set(vcpu, X86_FEATURE_TSCRATEMSR); =20 - svm->tsc_scaling_enabled =3D tsc_scaling && guest_cpuid_has(vcpu, X86_FEA= TURE_TSCRATEMSR); svm->lbrv_enabled =3D lbrv && guest_cpuid_has(vcpu, X86_FEATURE_LBRV); =20 svm->v_vmload_vmsave_enabled =3D vls && guest_cpuid_has(vcpu, X86_FEATURE= _V_VMSAVE_VMLOAD); diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h index c06de55425d4..4e7332f77702 100644 --- a/arch/x86/kvm/svm/svm.h +++ b/arch/x86/kvm/svm/svm.h @@ -259,7 +259,6 @@ struct vcpu_svm { bool soft_int_injected; =20 /* optional nested SVM features that are enabled for this guest */ - bool tsc_scaling_enabled : 1; bool v_vmload_vmsave_enabled : 1; bool lbrv_enabled : 1; bool pause_filter_enabled : 1; --=20 2.41.0.487.g6d72f3e995-goog