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=-6.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT 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 8DE27C2D0C6 for ; Wed, 11 Dec 2019 16:12:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5FC3B2173E for ; Wed, 11 Dec 2019 16:12:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1576080742; bh=139vf3DfrbkU/P4JhYzf52gZ3HQgEWtbHarbgTFRTQU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=o5NDpLXb7HTDVih0eC/x2JsjMhjUVNMaZI3OXD7CTEo8DpjTxJoHAqKXLzP9FvxGE LKu2Bk1XNf0DzXs+gS2JffZsjA9vcWfQjNBl+lY1UUlS1h5K2lY93rqJunuw/SB9xR CFnM8GXd8VpZTX9R0xaKVYo+Amdausj4CmteTOYQ= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730639AbfLKPJm (ORCPT ); Wed, 11 Dec 2019 10:09:42 -0500 Received: from mail.kernel.org ([198.145.29.99]:57714 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730141AbfLKPJh (ORCPT ); Wed, 11 Dec 2019 10:09:37 -0500 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 399232465B; Wed, 11 Dec 2019 15:09:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1576076976; bh=139vf3DfrbkU/P4JhYzf52gZ3HQgEWtbHarbgTFRTQU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Zul2SulS4U/oQJpR0RzxztOcyxXg/xNqLQPmykcmMO7Jlnua40/bcyU6+JwRHuTQv 6M/Qj6cwEcgl+UIKbKm/0/7lFlqHYoOhbRLE7AJvmEhCsdDEjrRUj1PPpKUtziokZq aTDnVFSM82ogFnybkLxaqfv7dhsSsUEFQAdcoPXA= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Vitaly Kuznetsov , Liran Alon , Sean Christopherson , Jim Mattson , Paolo Bonzini , Reto Buerki Subject: [PATCH 5.4 62/92] KVM: nVMX: Always write vmcs02.GUEST_CR3 during nested VM-Enter Date: Wed, 11 Dec 2019 16:05:53 +0100 Message-Id: <20191211150251.817846556@linuxfoundation.org> X-Mailer: git-send-email 2.24.1 In-Reply-To: <20191211150221.977775294@linuxfoundation.org> References: <20191211150221.977775294@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Sean Christopherson commit 04f11ef45810da5ae2542dd78cc353f3761bd2cb upstream. Write the desired L2 CR3 into vmcs02.GUEST_CR3 during nested VM-Enter instead of deferring the VMWRITE until vmx_set_cr3(). If the VMWRITE is deferred, then KVM can consume a stale vmcs02.GUEST_CR3 when it refreshes vmcs12->guest_cr3 during nested_vmx_vmexit() if the emulated VM-Exit occurs without actually entering L2, e.g. if the nested run is squashed because nested VM-Enter (from L1) is putting L2 into HLT. Note, the above scenario can occur regardless of whether L1 is intercepting HLT, e.g. L1 can intercept HLT and then re-enter L2 with vmcs.GUEST_ACTIVITY_STATE=HALTED. But practically speaking, a VMM will likely put a guest into HALTED if and only if it's not intercepting HLT. In an ideal world where EPT *requires* unrestricted guest (and vice versa), VMX could handle CR3 similar to how it handles RSP and RIP, e.g. mark CR3 dirty and conditionally load it at vmx_vcpu_run(). But the unrestricted guest silliness complicates the dirty tracking logic to the point that explicitly handling vmcs02.GUEST_CR3 during nested VM-Enter is a simpler overall implementation. Cc: stable@vger.kernel.org Reported-and-tested-by: Reto Buerki Tested-by: Vitaly Kuznetsov Reviewed-by: Liran Alon Signed-off-by: Sean Christopherson Reviewed-by: Jim Mattson Signed-off-by: Paolo Bonzini Signed-off-by: Greg Kroah-Hartman --- arch/x86/kvm/vmx/nested.c | 10 ++++++++++ arch/x86/kvm/vmx/vmx.c | 10 +++++++--- 2 files changed, 17 insertions(+), 3 deletions(-) --- a/arch/x86/kvm/vmx/nested.c +++ b/arch/x86/kvm/vmx/nested.c @@ -2418,6 +2418,16 @@ static int prepare_vmcs02(struct kvm_vcp entry_failure_code)) return -EINVAL; + /* + * Immediately write vmcs02.GUEST_CR3. It will be propagated to vmcs12 + * on nested VM-Exit, which can occur without actually running L2 and + * thus without hitting vmx_set_cr3(), e.g. if L1 is entering L2 with + * vmcs12.GUEST_ACTIVITYSTATE=HLT, in which case KVM will intercept the + * transition to HLT instead of running L2. + */ + if (enable_ept) + vmcs_writel(GUEST_CR3, vmcs12->guest_cr3); + /* Late preparation of GUEST_PDPTRs now that EFER and CRs are set. */ if (load_guest_pdptrs_vmcs12 && nested_cpu_has_ept(vmcs12) && is_pae_paging(vcpu)) { --- a/arch/x86/kvm/vmx/vmx.c +++ b/arch/x86/kvm/vmx/vmx.c @@ -2995,6 +2995,7 @@ u64 construct_eptp(struct kvm_vcpu *vcpu void vmx_set_cr3(struct kvm_vcpu *vcpu, unsigned long cr3) { struct kvm *kvm = vcpu->kvm; + bool update_guest_cr3 = true; unsigned long guest_cr3; u64 eptp; @@ -3011,15 +3012,18 @@ void vmx_set_cr3(struct kvm_vcpu *vcpu, spin_unlock(&to_kvm_vmx(kvm)->ept_pointer_lock); } - if (enable_unrestricted_guest || is_paging(vcpu) || - is_guest_mode(vcpu)) + /* 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)) guest_cr3 = kvm_read_cr3(vcpu); else guest_cr3 = to_kvm_vmx(kvm)->ept_identity_map_addr; ept_load_pdptrs(vcpu); } - vmcs_writel(GUEST_CR3, guest_cr3); + if (update_guest_cr3) + vmcs_writel(GUEST_CR3, guest_cr3); } int vmx_set_cr4(struct kvm_vcpu *vcpu, unsigned long cr4)