From nobody Thu Sep 11 16:10:51 2025 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 48D9DC07E8C for ; Tue, 15 Aug 2023 20:38:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238973AbjHOUib (ORCPT ); Tue, 15 Aug 2023 16:38:31 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33672 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238950AbjHOUh7 (ORCPT ); Tue, 15 Aug 2023 16:37:59 -0400 Received: from mail-yw1-x114a.google.com (mail-yw1-x114a.google.com [IPv6:2607:f8b0:4864:20::114a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1E8F11FF9 for ; Tue, 15 Aug 2023 13:37:35 -0700 (PDT) Received: by mail-yw1-x114a.google.com with SMTP id 00721157ae682-589fae40913so28344697b3.0 for ; Tue, 15 Aug 2023 13:37:35 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20221208; t=1692131832; x=1692736632; 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=/gyHxemWXBUuNtn9G6ZmWdv+kLBQgF3gAw0dAQJK39U=; b=QjV9eR7WVBYauzi+3qEmMZRbGnogEfU+B0zFQOnCsCmKlA5Y7+WABAvNAKoUACRX2L FJ7bX6MfATSvoHUMEjiRdyOyWdK7TAlddykPKqbCqchQezNPP6N6uWjI6TcTnnONoQOo Y7zIs8TyBi4tOanPhjiQgenTT3IGnkss334NihSIzpzM+0JLpXHYP+bxavbA3mzM5b4e cQ5Tm47QyV+q1KcQgqcNOl3dUPAgOeWXukEWRpmrEqdobuhlJXP8E+uEKa/EOYHQPTBY ltSICRi8gyLsbi/nOUR5RjYVMs8l1CUTjh/OVD9xL22H1feIKA+awmeD6atr/MdsHmTo 2iGQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1692131832; x=1692736632; 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=/gyHxemWXBUuNtn9G6ZmWdv+kLBQgF3gAw0dAQJK39U=; b=AdvxGUSgb0y+Oq3xxFvro+Tv5YuQ6JUdgl3fM1r/hiIngF//xSqwM29jyX81Plg5nw Bk4Lic50SN6eAdFKrG3oeZeP7Vv7+WZ/Hg4+b8dX8UwcGOqRmXdqMcfeZ4SbLX/t5KBw 7iiIN2qYHkIT7bwC8VqcFa9PUtwK9m+wy3FoxKPOPM22/4HJlpLYqg/K/411vlKcoNhc zLZdQ7HbP8aMQCMELwSp32DdkJnGLA1Vbicf0hJeHL/mw8xxMjqx5z6wtYfiwKeayVco jHAL0acteFeWFMXSsQwKlUjqiK43avsxp7qt5JhhcsLt75mwX7HyLjQp7lcAqQiQEAje /0xA== X-Gm-Message-State: AOJu0YzvToCafLrSiWH8wu6x39j4mj5I6pWpPDGZG1fWEUrMNdSe74v+ H62DeNKTDzp/FNnh5OA+m6GMlQOs7fk= X-Google-Smtp-Source: AGHT+IGI0BUgnGQhn/IYqVCfzOsUxVZRnsC+Kr6E6SXC6uQOYKMqqfBcEmr5TP2ZI+7oiAkj1r2Qc7Km70Q= X-Received: from zagreus.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:5c37]) (user=seanjc job=sendgmr) by 2002:a05:6902:4c7:b0:d5d:511b:16da with SMTP id v7-20020a05690204c700b00d5d511b16damr180847ybs.2.1692131832254; Tue, 15 Aug 2023 13:37:12 -0700 (PDT) Reply-To: Sean Christopherson Date: Tue, 15 Aug 2023 13:36:47 -0700 In-Reply-To: <20230815203653.519297-1-seanjc@google.com> Mime-Version: 1.0 References: <20230815203653.519297-1-seanjc@google.com> X-Mailer: git-send-email 2.41.0.694.ge786442a9b-goog Message-ID: <20230815203653.519297-10-seanjc@google.com> Subject: [PATCH v3 09/15] 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, Zeng Guang , Yuan Yao 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 Reviewed-by: Yuan Yao --- 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 c8b97cb3138c..15c79457d8c5 100644 --- a/arch/x86/kvm/svm/svm.c +++ b/arch/x86/kvm/svm/svm.c @@ -2809,7 +2809,8 @@ 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; @@ -2959,7 +2960,7 @@ 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; @@ -2981,7 +2982,8 @@ 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; @@ -4289,8 +4291,8 @@ 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 e147f2046ffa..3696f10e2887 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 2.41.0.694.ge786442a9b-goog