From patchwork Mon Jul 12 06:06:22 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 475803 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=-19.5 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, USER_AGENT_GIT 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 5F560C11F81 for ; Mon, 12 Jul 2021 07:10:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4106F60BD3 for ; Mon, 12 Jul 2021 07:10:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S242276AbhGLHMt (ORCPT ); Mon, 12 Jul 2021 03:12:49 -0400 Received: from mail.kernel.org ([198.145.29.99]:45090 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S244188AbhGLHK3 (ORCPT ); Mon, 12 Jul 2021 03:10:29 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 0F536613D0; Mon, 12 Jul 2021 07:06:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1626073615; bh=T6NX1U575lJXClTcLuQEFii2Y/SyCBgpuluINec1QjQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=x2mLG8PzSIINJyZ0mGC0qQBQJOlXnn0OKnniB/70Y+WrhEBG6d9QiCuGzN7mbA1I3 9ImEEn9CfNJJqlj8azlmsA846pGTp4Kq2OARovaocbaZ2HJhYgPyUDIxUhdtjqsmmZ EThHspo93UwrC9NRX5WQJeK1Q8hz/1nxGHzdrKoo= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Sean Christopherson , Paolo Bonzini , Sasha Levin Subject: [PATCH 5.12 299/700] KVM: nVMX: Dont clobber nested MMUs A/D status on EPTP switch Date: Mon, 12 Jul 2021 08:06:22 +0200 Message-Id: <20210712061008.175289683@linuxfoundation.org> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20210712060924.797321836@linuxfoundation.org> References: <20210712060924.797321836@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Sean Christopherson [ Upstream commit 272b0a998d084e7667284bdd2d0c675c6a2d11de ] Drop bogus logic that incorrectly clobbers the accessed/dirty enabling status of the nested MMU on an EPTP switch. When nested EPT is enabled, walk_mmu points at L2's _legacy_ page tables, not L1's EPT for L2. This is likely a benign bug, as mmu->ept_ad is never consumed (since the MMU is not a nested EPT MMU), and stuffing mmu_role.base.ad_disabled will never propagate into future shadow pages since the nested MMU isn't used to map anything, just to walk L2's page tables. Note, KVM also does a full MMU reload, i.e. the guest_mmu will be recreated using the new EPTP, and thus any change in A/D enabling will be properly recognized in the relevant MMU. Fixes: 41ab93727467 ("KVM: nVMX: Emulate EPTP switching for the L1 hypervisor") Signed-off-by: Sean Christopherson Message-Id: <20210609234235.1244004-4-seanjc@google.com> Signed-off-by: Paolo Bonzini Signed-off-by: Sasha Levin --- arch/x86/kvm/vmx/nested.c | 7 ------- 1 file changed, 7 deletions(-) diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c index d3774d79916d..618dcf11d688 100644 --- a/arch/x86/kvm/vmx/nested.c +++ b/arch/x86/kvm/vmx/nested.c @@ -5472,8 +5472,6 @@ static int nested_vmx_eptp_switching(struct kvm_vcpu *vcpu, { u32 index = kvm_rcx_read(vcpu); u64 new_eptp; - bool accessed_dirty; - struct kvm_mmu *mmu = vcpu->arch.walk_mmu; if (!nested_cpu_has_eptp_switching(vmcs12) || !nested_cpu_has_ept(vmcs12)) @@ -5482,13 +5480,10 @@ static int nested_vmx_eptp_switching(struct kvm_vcpu *vcpu, if (index >= VMFUNC_EPTP_ENTRIES) return 1; - if (kvm_vcpu_read_guest_page(vcpu, vmcs12->eptp_list_address >> PAGE_SHIFT, &new_eptp, index * 8, 8)) return 1; - accessed_dirty = !!(new_eptp & VMX_EPTP_AD_ENABLE_BIT); - /* * If the (L2) guest does a vmfunc to the currently * active ept pointer, we don't have to do anything else @@ -5497,8 +5492,6 @@ static int nested_vmx_eptp_switching(struct kvm_vcpu *vcpu, if (!nested_vmx_check_eptp(vcpu, new_eptp)) return 1; - mmu->ept_ad = accessed_dirty; - mmu->mmu_role.base.ad_disabled = !accessed_dirty; vmcs12->ept_pointer = new_eptp; kvm_make_request(KVM_REQ_MMU_RELOAD, vcpu);