From nobody Sun Feb 8 16:50:26 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 3FCB9C001DF for ; Sat, 29 Jul 2023 01:18:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237369AbjG2BS1 (ORCPT ); Fri, 28 Jul 2023 21:18:27 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36114 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237455AbjG2BRk (ORCPT ); Fri, 28 Jul 2023 21:17:40 -0400 Received: from mail-yb1-xb49.google.com (mail-yb1-xb49.google.com [IPv6:2607:f8b0:4864:20::b49]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4DD0849F2 for ; Fri, 28 Jul 2023 18:17:10 -0700 (PDT) Received: by mail-yb1-xb49.google.com with SMTP id 3f1490d57ef6-d1bcb99b518so2503001276.2 for ; Fri, 28 Jul 2023 18:17:10 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20221208; t=1690593403; x=1691198203; 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=RivGO1zReamo45LkTKZurMbG/2NW5Na6scf+1QseqDY=; b=hIQtvbpt0HUSaqF39Lk9Xfa9TrQTmVjU7RALdaw1fEsbZtAiuObGnFR0Gku+I64fsr EVrNvlR/IQ3tigJBye53R3SEyQq9ap5sEjRS/w2ib/Nbaz6ND/a27qXUH/r81czS+i95 +4M/PpgfVpbnHAK78VBIkHZWNOg/uMCvRhbsbRb5Hz+3PclOkZWQ3b+JNlm+EY4AMFDN 20KHnMdzEj16XfUGCUjYSYQTHQI7CuKSHt/AuA1oUQSVbnuRFX7uwRCDJlxDMZO7lCzE 2180eCxVHw5kgi3tfuffiJsVwm2w8dHM1viduqd8KLxmLQDiaS63Vsh1giEXn7bIp+Nv Jtog== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1690593403; x=1691198203; 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=RivGO1zReamo45LkTKZurMbG/2NW5Na6scf+1QseqDY=; b=M3v4jlEiEsD0zGN1vM8KG5d42ZZ4N/FuuSYJLYrYA9cF8IbIylT8PQ6Hi2Z0pJsqkp mdDjaEvkK78Mctv+vrVkYsGMHp4V5+AR8BvkZqqZRloYqw3bCXkXDIwPDX9W4dFp9B4T R1z/IIbvFqlzT0QKWtGxObGE1dP1zlOJVakB3kXXClTKdpOILcQhgEr351s04zsR5eXQ BQVbW612m2gPneZcCmM+47UyF0ls//8Qxj2Q1eVOYxOOlRrV3l3pFvzwCUZlf3xSObRq PyydPwqT3ybj2RWPUzcaYKY7BNGzF5xO7i7cMEOuIQyUYQxcpUA9DmEj+UT+vux5IoLm YVeA== X-Gm-Message-State: ABy/qLYt/ec3n+3ILlar3IaH3YgoNu0mBbTCc1zCiwFIaVv0uXAr4FfV Gt5Uh2rmSFkb0P+u20Z0Y7Z598Uj2NU= X-Google-Smtp-Source: APBJJlFzrRMu/FipBCWOALymzRtbc31rIKvodpA1k0Hng04DLRC6eCO5Q8u++IKFWaiaXRNNRrLr5Q/WTcQ= X-Received: from zagreus.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:5c37]) (user=seanjc job=sendgmr) by 2002:a25:2d1a:0:b0:d0c:77a8:1f6b with SMTP id t26-20020a252d1a000000b00d0c77a81f6bmr20040ybt.10.1690593403726; Fri, 28 Jul 2023 18:16:43 -0700 (PDT) Reply-To: Sean Christopherson Date: Fri, 28 Jul 2023 18:16:03 -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: <20230729011608.1065019-17-seanjc@google.com> Subject: [PATCH v2 16/21] KVM: nSVM: Use KVM-governed feature framework to track "vVM{SAVE,LOAD} 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 "virtual VMSAVE/VMLOAD exposed to L1" via a governed feature flag instead of using a dedicated bit/flag in vcpu_svm. Opportunistically add a comment explaining why KVM disallows virtual VMLOAD/VMSAVE when the vCPU model is Intel. No functional change intended. 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, 9 insertions(+), 5 deletions(-) diff --git a/arch/x86/kvm/governed_features.h b/arch/x86/kvm/governed_featu= res.h index 32c0469cf952..f01a95fd0071 100644 --- a/arch/x86/kvm/governed_features.h +++ b/arch/x86/kvm/governed_features.h @@ -10,6 +10,7 @@ KVM_GOVERNED_X86_FEATURE(XSAVES) KVM_GOVERNED_X86_FEATURE(VMX) KVM_GOVERNED_X86_FEATURE(NRIPS) KVM_GOVERNED_X86_FEATURE(TSCRATEMSR) +KVM_GOVERNED_X86_FEATURE(V_VMSAVE_VMLOAD) =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 da65948064dc..24d47ebeb0e0 100644 --- a/arch/x86/kvm/svm/nested.c +++ b/arch/x86/kvm/svm/nested.c @@ -107,7 +107,7 @@ static void nested_svm_uninit_mmu_context(struct kvm_vc= pu *vcpu) =20 static bool nested_vmcb_needs_vls_intercept(struct vcpu_svm *svm) { - if (!svm->v_vmload_vmsave_enabled) + if (!guest_can_use(&svm->vcpu, X86_FEATURE_V_VMSAVE_VMLOAD)) return true; =20 if (!nested_npt_enabled(svm)) diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c index 2f7f7df5a591..39a69c1786ea 100644 --- a/arch/x86/kvm/svm/svm.c +++ b/arch/x86/kvm/svm/svm.c @@ -1154,8 +1154,6 @@ static inline void init_vmcb_after_set_cpuid(struct k= vm_vcpu *vcpu) =20 set_msr_interception(vcpu, svm->msrpm, MSR_IA32_SYSENTER_EIP, 0, 0); set_msr_interception(vcpu, svm->msrpm, MSR_IA32_SYSENTER_ESP, 0, 0); - - svm->v_vmload_vmsave_enabled =3D false; } else { /* * If hardware supports Virtual VMLOAD VMSAVE then enable it @@ -4226,7 +4224,13 @@ static void svm_vcpu_after_set_cpuid(struct kvm_vcpu= *vcpu) =20 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); + /* + * Intercept VMLOAD if the vCPU mode is Intel in order to emulate that + * VMLOAD drops bits 63:32 of SYSENTER (ignoring the fact that exposing + * SVM on Intel is bonkers and extremely unlikely to work). + */ + if (!guest_cpuid_is_intel(vcpu)) + kvm_governed_feature_check_and_set(vcpu, X86_FEATURE_V_VMSAVE_VMLOAD); =20 svm->pause_filter_enabled =3D kvm_cpu_cap_has(X86_FEATURE_PAUSEFILTER) && guest_cpuid_has(vcpu, X86_FEATURE_PAUSEFILTER); diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h index 4e7332f77702..b475241df6dc 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 v_vmload_vmsave_enabled : 1; bool lbrv_enabled : 1; bool pause_filter_enabled : 1; bool pause_threshold_enabled : 1; --=20 2.41.0.487.g6d72f3e995-goog