From nobody Sun Feb 8 20:00:15 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 F1B0CC0015E for ; Sat, 29 Jul 2023 01:18:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237219AbjG2BSP (ORCPT ); Fri, 28 Jul 2023 21:18:15 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35928 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237393AbjG2BRg (ORCPT ); Fri, 28 Jul 2023 21:17:36 -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 0F17855A9 for ; Fri, 28 Jul 2023 18:17:06 -0700 (PDT) Received: by mail-pl1-x64a.google.com with SMTP id d9443c01a7336-1bbbc4ae328so20393585ad.1 for ; Fri, 28 Jul 2023 18:17:05 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20221208; t=1690593398; x=1691198198; 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=ZBstFzzUxVyW0UD2LT3q1n62xfHDtx4xPYrvh1DuKtE=; b=AWA3eueKfdIcRemXTjYfiddcMtJI0gM8qgAv12KCTw4HqUU0shQMSFOxKJIqy4vXKo o6PGd++MfofA37Ilb4CdFRIImOYn0LHj5TT/u1y6lKa9cwtHyqNqTYJcxTPFrFc5HcMg EzkaGymUsTaNE6uXUIiX2/rTAeuI23PlQHZzCKwbbJLVpdsqh7sHcY7VRZn0qolmfCBn sXyDMqpc2/A4JbuFGUtM7AmJ5Kvx2y7QHKtKaD736u9Q81xpRZHnJtwpiSI05j1+W0Hx gPZA0p3nGewQVfW/euy/AuhF4Bt3UH3aB9Rmw0+o18MlQzaEbSF8ZXWj2V8m1ocyJGws Bj/Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1690593398; x=1691198198; 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=ZBstFzzUxVyW0UD2LT3q1n62xfHDtx4xPYrvh1DuKtE=; b=BpMghsoJtiZG7BkzrF1eXNCnhUDC+Ih7FDx8bHsSDrO/RsqxVfcZchR8D7tTWFuIut WueIx+snl+kynWmOGrPRAdkhuc0EQWfCq/KHEQxXgRqnXqbgrCaaMxChEZghNHzgeZUW GtYvz/wfbLMWw5WMhT/pK1EqZdJj/D9RoC5i32ckDUtwURg1Xnf7oLBGWGivZyBSaboi VJXv9xymmlvVf7plt1x49Sl/gEY4SgimrovQqMOgMbAsFwzg6MUpaUfVLz3QJaoJY+xp m0wwmDIY+GFDODc0l9FwKkCbRZCPPEVnWNfhKOpEI9pVJMByAV84a8oHtJpibF2qeARk QJ7A== X-Gm-Message-State: ABy/qLZP5njHzNBZAVzkFR5V++Q2rFdt1BsQuT6FZWl2WDqtL/wSFdhZ aM+9Akv1D37Wu7D8+O3Fdqmul/6Nfzk= X-Google-Smtp-Source: APBJJlE9gJP2mXJxfkwEVOlLCgzzX3TWKCeVQjYElvF6CgWBwkyCaatBW6oKGQdFMvEvR4lm9CkyS6Qtl1s= X-Received: from zagreus.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:5c37]) (user=seanjc job=sendgmr) by 2002:a17:902:e542:b0:1b8:c666:207a with SMTP id n2-20020a170902e54200b001b8c666207amr13470plf.9.1690593398073; Fri, 28 Jul 2023 18:16:38 -0700 (PDT) Reply-To: Sean Christopherson Date: Fri, 28 Jul 2023 18:16:00 -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: <20230729011608.1065019-14-seanjc@google.com> Subject: [PATCH v2 13/21] KVM: nVMX: Use KVM-governed feature framework to track "nested VMX 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 "VMX exposed to L1" via a governed feature flag instead of using a dedicated helper to provide the same functionality. The main goal is to drive convergence between VMX and SVM with respect to querying features that are controllable via module param (SVM likes to cache nested features), avoiding the guest CPUID lookups at runtime is just a bonus and unlikely to provide any meaningful performance benefits. No functional change intended. Signed-off-by: Sean Christopherson Reviewed-by: Yuan Yao --- arch/x86/kvm/governed_features.h | 1 + arch/x86/kvm/vmx/nested.c | 7 ++++--- arch/x86/kvm/vmx/vmx.c | 21 ++++++--------------- arch/x86/kvm/vmx/vmx.h | 1 - 4 files changed, 11 insertions(+), 19 deletions(-) diff --git a/arch/x86/kvm/governed_features.h b/arch/x86/kvm/governed_featu= res.h index b896a64e4ac3..22446614bf49 100644 --- a/arch/x86/kvm/governed_features.h +++ b/arch/x86/kvm/governed_features.h @@ -7,6 +7,7 @@ BUILD_BUG() =20 KVM_GOVERNED_X86_FEATURE(GBPAGES) KVM_GOVERNED_X86_FEATURE(XSAVES) +KVM_GOVERNED_X86_FEATURE(VMX) =20 #undef KVM_GOVERNED_X86_FEATURE #undef KVM_GOVERNED_FEATURE diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c index 22e08d30baef..c5ec0ef51ff7 100644 --- a/arch/x86/kvm/vmx/nested.c +++ b/arch/x86/kvm/vmx/nested.c @@ -6426,7 +6426,7 @@ static int vmx_get_nested_state(struct kvm_vcpu *vcpu, vmx =3D to_vmx(vcpu); vmcs12 =3D get_vmcs12(vcpu); =20 - if (nested_vmx_allowed(vcpu) && + if (guest_can_use(vcpu, X86_FEATURE_VMX) && (vmx->nested.vmxon || vmx->nested.smm.vmxon)) { kvm_state.hdr.vmx.vmxon_pa =3D vmx->nested.vmxon_ptr; kvm_state.hdr.vmx.vmcs12_pa =3D vmx->nested.current_vmptr; @@ -6567,7 +6567,7 @@ static int vmx_set_nested_state(struct kvm_vcpu *vcpu, if (kvm_state->flags & ~KVM_STATE_NESTED_EVMCS) return -EINVAL; } else { - if (!nested_vmx_allowed(vcpu)) + if (!guest_can_use(vcpu, X86_FEATURE_VMX)) return -EINVAL; =20 if (!page_address_valid(vcpu, kvm_state->hdr.vmx.vmxon_pa)) @@ -6601,7 +6601,8 @@ static int vmx_set_nested_state(struct kvm_vcpu *vcpu, return -EINVAL; =20 if ((kvm_state->flags & KVM_STATE_NESTED_EVMCS) && - (!nested_vmx_allowed(vcpu) || !vmx->nested.enlightened_vmcs_enabled)) + (!guest_can_use(vcpu, X86_FEATURE_VMX) || + !vmx->nested.enlightened_vmcs_enabled)) return -EINVAL; =20 vmx_leave_nested(vcpu); diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c index 3100ed62615c..fdf932cfc64d 100644 --- a/arch/x86/kvm/vmx/vmx.c +++ b/arch/x86/kvm/vmx/vmx.c @@ -1894,17 +1894,6 @@ static void vmx_write_tsc_multiplier(struct kvm_vcpu= *vcpu) vmcs_write64(TSC_MULTIPLIER, vcpu->arch.tsc_scaling_ratio); } =20 -/* - * nested_vmx_allowed() checks whether a guest should be allowed to use VMX - * instructions and MSRs (i.e., nested VMX). Nested VMX is disabled for - * all guests if the "nested" module option is off, and can also be disabl= ed - * for a single guest by disabling its VMX cpuid bit. - */ -bool nested_vmx_allowed(struct kvm_vcpu *vcpu) -{ - return nested && guest_cpuid_has(vcpu, X86_FEATURE_VMX); -} - /* * Userspace is allowed to set any supported IA32_FEATURE_CONTROL regardle= ss of * guest CPUID. Note, KVM allows userspace to set "VMX in SMX" to maintain @@ -2032,7 +2021,7 @@ static int vmx_get_msr(struct kvm_vcpu *vcpu, struct = msr_data *msr_info) [msr_info->index - MSR_IA32_SGXLEPUBKEYHASH0]; break; case KVM_FIRST_EMULATED_VMX_MSR ... KVM_LAST_EMULATED_VMX_MSR: - if (!nested_vmx_allowed(vcpu)) + if (!guest_can_use(vcpu, X86_FEATURE_VMX)) return 1; if (vmx_get_vmx_msr(&vmx->nested.msrs, msr_info->index, &msr_info->data)) @@ -2340,7 +2329,7 @@ static int vmx_set_msr(struct kvm_vcpu *vcpu, struct = msr_data *msr_info) case KVM_FIRST_EMULATED_VMX_MSR ... KVM_LAST_EMULATED_VMX_MSR: if (!msr_info->host_initiated) return 1; /* they are read-only */ - if (!nested_vmx_allowed(vcpu)) + if (!guest_can_use(vcpu, X86_FEATURE_VMX)) return 1; return vmx_set_vmx_msr(vcpu, msr_index, data); case MSR_IA32_RTIT_CTL: @@ -7727,13 +7716,15 @@ static void vmx_vcpu_after_set_cpuid(struct kvm_vcp= u *vcpu) guest_cpuid_has(vcpu, X86_FEATURE_XSAVE)) kvm_governed_feature_check_and_set(vcpu, X86_FEATURE_XSAVES); =20 + kvm_governed_feature_check_and_set(vcpu, X86_FEATURE_VMX); + vmx_setup_uret_msrs(vmx); =20 if (cpu_has_secondary_exec_ctrls()) vmcs_set_secondary_exec_control(vmx, vmx_secondary_exec_control(vmx)); =20 - if (nested_vmx_allowed(vcpu)) + if (guest_can_use(vcpu, X86_FEATURE_VMX)) vmx->msr_ia32_feature_control_valid_bits |=3D FEAT_CTL_VMX_ENABLED_INSIDE_SMX | FEAT_CTL_VMX_ENABLED_OUTSIDE_SMX; @@ -7742,7 +7733,7 @@ static void vmx_vcpu_after_set_cpuid(struct kvm_vcpu = *vcpu) ~(FEAT_CTL_VMX_ENABLED_INSIDE_SMX | FEAT_CTL_VMX_ENABLED_OUTSIDE_SMX); =20 - if (nested_vmx_allowed(vcpu)) + if (guest_can_use(vcpu, X86_FEATURE_VMX)) nested_vmx_cr_fixed1_bits_update(vcpu); =20 if (boot_cpu_has(X86_FEATURE_INTEL_PT) && diff --git a/arch/x86/kvm/vmx/vmx.h b/arch/x86/kvm/vmx/vmx.h index cde902b44d97..c2130d2c8e24 100644 --- a/arch/x86/kvm/vmx/vmx.h +++ b/arch/x86/kvm/vmx/vmx.h @@ -374,7 +374,6 @@ struct kvm_vmx { u64 *pid_table; }; =20 -bool nested_vmx_allowed(struct kvm_vcpu *vcpu); void vmx_vcpu_load_vmcs(struct kvm_vcpu *vcpu, int cpu, struct loaded_vmcs *buddy); int allocate_vpid(void); --=20 2.41.0.487.g6d72f3e995-goog