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 X-Spam-Level: X-Spam-Status: No, score=-9.9 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1344BC433F1 for ; Fri, 10 Jul 2020 14:12:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E4E2E207D0 for ; Fri, 10 Jul 2020 14:12:45 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="Rhd52J9z" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728293AbgGJOM3 (ORCPT ); Fri, 10 Jul 2020 10:12:29 -0400 Received: from us-smtp-1.mimecast.com ([207.211.31.81]:22634 "EHLO us-smtp-delivery-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1728252AbgGJOMY (ORCPT ); Fri, 10 Jul 2020 10:12:24 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1594390342; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=3HxPZNflIjOanh3umlNWu4ZNeWzdk02qhGTFsksEXGU=; b=Rhd52J9z2fbSHya77U+vUyop8hcfyFuWDZVws18oS7BSDBmE5QQq7Vc3SluLJwtVFpPr3M lpOZH+3Vj2gPiY3W162Sn1C7K5AIpXUNjrfk40Oc1tP7rKO8xCmPq2JIqCPZxk8OssSY9e QBKqdBEKJ1qIRrljPdRz6XkwDtg7mmQ= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-215-TxYRBx6VMAK4YQM2gURO3w-1; Fri, 10 Jul 2020 10:12:20 -0400 X-MC-Unique: TxYRBx6VMAK4YQM2gURO3w-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 789AB102C7EC; Fri, 10 Jul 2020 14:12:19 +0000 (UTC) Received: from vitty.brq.redhat.com (unknown [10.40.195.35]) by smtp.corp.redhat.com (Postfix) with ESMTP id 00D481CA; Fri, 10 Jul 2020 14:12:16 +0000 (UTC) From: Vitaly Kuznetsov To: kvm@vger.kernel.org, Paolo Bonzini Cc: Sean Christopherson , Wanpeng Li , Jim Mattson , Junaid Shahid , linux-kernel@vger.kernel.org Subject: [PATCH v4 7/9] KVM: nSVM: implement nested_svm_load_cr3() and use it for host->guest switch Date: Fri, 10 Jul 2020 16:11:55 +0200 Message-Id: <20200710141157.1640173-8-vkuznets@redhat.com> In-Reply-To: <20200710141157.1640173-1-vkuznets@redhat.com> References: <20200710141157.1640173-1-vkuznets@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Undesired triple fault gets injected to L1 guest on SVM when L2 is launched with certain CR3 values. #TF is raised by mmu_check_root() check in fast_pgd_switch() and the root cause is that when kvm_set_cr3() is called from nested_prepare_vmcb_save() with NPT enabled CR3 points to a nGPA so we can't check it with kvm_is_visible_gfn(). Using generic kvm_set_cr3() when switching to nested guest is not a great idea as we'll have to distinguish between 'real' CR3s and 'nested' CR3s to e.g. not call kvm_mmu_new_pgd() with nGPA. Following nVMX implement nested-specific nested_svm_load_cr3() doing the job. To support the change, nested_svm_load_cr3() needs to be re-ordered with nested_svm_init_mmu_context(). Note: the current implementation is sub-optimal as we always do TLB flush/MMU sync but this is still an improvement as we at least stop doing kvm_mmu_reset_context(). Fixes: 7c390d350f8b ("kvm: x86: Add fast CR3 switch code path") Signed-off-by: Vitaly Kuznetsov --- arch/x86/kvm/mmu/mmu.c | 2 ++ arch/x86/kvm/svm/nested.c | 38 +++++++++++++++++++++++++++++--------- 2 files changed, 31 insertions(+), 9 deletions(-) diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index 3a306ab1a9c9..13ec3c30eda2 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -4986,6 +4986,8 @@ void kvm_init_shadow_npt_mmu(struct kvm_vcpu *vcpu, u32 cr0, u32 cr4, u32 efer, union kvm_mmu_role new_role = kvm_calc_shadow_mmu_root_page_role(vcpu, false); + __kvm_mmu_new_pgd(vcpu, nested_cr3, new_role.base, false, false); + if (new_role.as_u64 != context->mmu_role.as_u64) shadow_mmu_init_context(vcpu, context, cr0, cr4, efer, new_role); } diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c index 2c308dfa5468..219871752dc5 100644 --- a/arch/x86/kvm/svm/nested.c +++ b/arch/x86/kvm/svm/nested.c @@ -323,7 +323,28 @@ static inline bool nested_npt_enabled(struct vcpu_svm *svm) static int nested_svm_load_cr3(struct kvm_vcpu *vcpu, unsigned long cr3, bool nested_npt) { - return kvm_set_cr3(vcpu, cr3); + if (cr3 & rsvd_bits(cpuid_maxphyaddr(vcpu), 63)) + return -EINVAL; + + if (!nested_npt && is_pae_paging(vcpu) && + (cr3 != kvm_read_cr3(vcpu) || pdptrs_changed(vcpu))) { + if (!load_pdptrs(vcpu, vcpu->arch.walk_mmu, cr3)) + return -EINVAL; + } + + /* + * TODO: optimize unconditional TLB flush/MMU sync here and in + * kvm_init_shadow_npt_mmu(). + */ + if (!nested_npt) + kvm_mmu_new_pgd(vcpu, cr3, false, false); + + vcpu->arch.cr3 = cr3; + kvm_register_mark_available(vcpu, VCPU_EXREG_CR3); + + kvm_init_mmu(vcpu, false); + + return 0; } static void nested_prepare_vmcb_save(struct vcpu_svm *svm, struct vmcb *nested_vmcb) @@ -339,9 +360,6 @@ static void nested_prepare_vmcb_save(struct vcpu_svm *svm, struct vmcb *nested_v svm_set_efer(&svm->vcpu, nested_vmcb->save.efer); svm_set_cr0(&svm->vcpu, nested_vmcb->save.cr0); svm_set_cr4(&svm->vcpu, nested_vmcb->save.cr4); - (void)nested_svm_load_cr3(&svm->vcpu, nested_vmcb->save.cr3, - nested_npt_enabled(svm)); - svm->vmcb->save.cr2 = svm->vcpu.arch.cr2 = nested_vmcb->save.cr2; kvm_rax_write(&svm->vcpu, nested_vmcb->save.rax); kvm_rsp_write(&svm->vcpu, nested_vmcb->save.rsp); @@ -363,11 +381,6 @@ static void nested_prepare_vmcb_control(struct vcpu_svm *svm) if (nested_npt_enabled(svm)) nested_svm_init_mmu_context(&svm->vcpu); - /* Guest paging mode is active - reset mmu */ - kvm_mmu_reset_context(&svm->vcpu); - - svm_flush_tlb(&svm->vcpu); - svm->vmcb->control.tsc_offset = svm->vcpu.arch.tsc_offset = svm->vcpu.arch.l1_tsc_offset + svm->nested.ctl.tsc_offset; @@ -399,11 +412,18 @@ static void nested_prepare_vmcb_control(struct vcpu_svm *svm) int enter_svm_guest_mode(struct vcpu_svm *svm, u64 vmcb_gpa, struct vmcb *nested_vmcb) { + int ret; + svm->nested.vmcb = vmcb_gpa; load_nested_vmcb_control(svm, &nested_vmcb->control); nested_prepare_vmcb_save(svm, nested_vmcb); nested_prepare_vmcb_control(svm); + ret = nested_svm_load_cr3(&svm->vcpu, nested_vmcb->save.cr3, + nested_npt_enabled(svm)); + if (ret) + return ret; + svm_set_gif(svm, true); return 0; -- 2.25.4