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=-6.9 required=3.0 tests=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=ham 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 34544C433E1 for ; Wed, 20 May 2020 17:22:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 14498207D3 for ; Wed, 20 May 2020 17:22:41 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="CBGoqBS+" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728229AbgETRW1 (ORCPT ); Wed, 20 May 2020 13:22:27 -0400 Received: from us-smtp-delivery-1.mimecast.com ([205.139.110.120]:25287 "EHLO us-smtp-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1728198AbgETRWX (ORCPT ); Wed, 20 May 2020 13:22:23 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1589995342; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:in-reply-to:in-reply-to:references:references; bh=sA7KU69CrSpCKwMi1qZQq/oq6j1VkGR88tbNNKk0nb4=; b=CBGoqBS++6lpyQVnRK+pAElnlGjlPWi5Be74nXHY62DhWwgDI/ZQrUBU89J3zlcam4W/jg GZcwOeZ76RixszqKBmzLLjaVVkFp8DlkTLxWAVWW5j4Gzu1exDrNuvWcTEsEyPGvSmNvQf yvkD1UnhfWhICb4UniNNc6qRCmZGXTU= 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-286-fKrAhJzsNRe3nmIDSTmG8Q-1; Wed, 20 May 2020 13:22:17 -0400 X-MC-Unique: fKrAhJzsNRe3nmIDSTmG8Q-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id B50AA1009639; Wed, 20 May 2020 17:22:12 +0000 (UTC) Received: from virtlab511.virt.lab.eng.bos.redhat.com (virtlab511.virt.lab.eng.bos.redhat.com [10.19.152.198]) by smtp.corp.redhat.com (Postfix) with ESMTP id AD66760554; Wed, 20 May 2020 17:22:11 +0000 (UTC) From: Paolo Bonzini To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org Cc: vkuznets@redhat.com, Joerg Roedel Subject: [PATCH 21/24] KVM: x86: always update CR3 in VMCB Date: Wed, 20 May 2020 13:21:42 -0400 Message-Id: <20200520172145.23284-22-pbonzini@redhat.com> In-Reply-To: <20200520172145.23284-1-pbonzini@redhat.com> References: <20200520172145.23284-1-pbonzini@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org vmx_load_mmu_pgd is delaying the write of GUEST_CR3 to prepare_vmcs02 as an optimization, but this is only correct before the nested vmentry. If userspace is modifying CR3 with KVM_SET_SREGS after the VM has already been put in guest mode, the value of CR3 will not be updated. Remove the optimization, which almost never triggers anyway. This also applies to SVM, where the code was added in commit 689f3bf21628 ("KVM: x86: unify callbacks to load paging root", 2020-03-16) just to keep the two vendor-specific modules closer. Fixes: 04f11ef45810 ("KVM: nVMX: Always write vmcs02.GUEST_CR3 during nested VM-Enter") Fixes: 689f3bf21628 ("KVM: x86: unify callbacks to load paging root") Signed-off-by: Paolo Bonzini --- arch/x86/kvm/svm/nested.c | 6 +----- arch/x86/kvm/svm/svm.c | 16 +++++----------- arch/x86/kvm/vmx/vmx.c | 5 +---- 3 files changed, 7 insertions(+), 20 deletions(-) diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c index 19b6a7c954e8..087a04ae74e4 100644 --- a/arch/x86/kvm/svm/nested.c +++ b/arch/x86/kvm/svm/nested.c @@ -260,11 +260,7 @@ 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); - if (npt_enabled) { - svm->vmcb->save.cr3 = nested_vmcb->save.cr3; - svm->vcpu.arch.cr3 = nested_vmcb->save.cr3; - } else - (void)kvm_set_cr3(&svm->vcpu, nested_vmcb->save.cr3); + (void)kvm_set_cr3(&svm->vcpu, nested_vmcb->save.cr3); svm->vmcb->save.cr2 = svm->vcpu.arch.cr2 = nested_vmcb->save.cr2; kvm_rax_write(&svm->vcpu, nested_vmcb->save.rax); diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c index d8187d25fe04..56be704ffe95 100644 --- a/arch/x86/kvm/svm/svm.c +++ b/arch/x86/kvm/svm/svm.c @@ -3465,7 +3465,6 @@ static fastpath_t svm_vcpu_run(struct kvm_vcpu *vcpu) static void svm_load_mmu_pgd(struct kvm_vcpu *vcpu, unsigned long root) { struct vcpu_svm *svm = to_svm(vcpu); - bool update_guest_cr3 = true; unsigned long cr3; cr3 = __sme_set(root); @@ -3474,18 +3473,13 @@ static void svm_load_mmu_pgd(struct kvm_vcpu *vcpu, unsigned long root) mark_dirty(svm->vmcb, VMCB_NPT); /* Loading L2's CR3 is handled by enter_svm_guest_mode. */ - if (is_guest_mode(vcpu)) - update_guest_cr3 = false; - else if (test_bit(VCPU_EXREG_CR3, (ulong *)&vcpu->arch.regs_avail)) - cr3 = vcpu->arch.cr3; - else /* CR3 is already up-to-date. */ - update_guest_cr3 = false; + if (!test_bit(VCPU_EXREG_CR3, (ulong *)&vcpu->arch.regs_avail)) + return; + cr3 = vcpu->arch.cr3; } - if (update_guest_cr3) { - svm->vmcb->save.cr3 = cr3; - mark_dirty(svm->vmcb, VMCB_CR); - } + svm->vmcb->save.cr3 = cr3; + mark_dirty(svm->vmcb, VMCB_CR); } static int is_disabled(void) diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c index 55712dd86baf..7daf6a50e774 100644 --- a/arch/x86/kvm/vmx/vmx.c +++ b/arch/x86/kvm/vmx/vmx.c @@ -3085,10 +3085,7 @@ void vmx_load_mmu_pgd(struct kvm_vcpu *vcpu, unsigned long pgd) spin_unlock(&to_kvm_vmx(kvm)->ept_pointer_lock); } - /* Loading vmcs02.GUEST_CR3 is handled by nested VM-Enter. */ - if (is_guest_mode(vcpu)) - update_guest_cr3 = false; - else if (!enable_unrestricted_guest && !is_paging(vcpu)) + if (!enable_unrestricted_guest && !is_paging(vcpu)) guest_cr3 = to_kvm_vmx(kvm)->ept_identity_map_addr; else if (test_bit(VCPU_EXREG_CR3, (ulong *)&vcpu->arch.regs_avail)) guest_cr3 = vcpu->arch.cr3; -- 2.18.2