From mboxrd@z Thu Jan 1 00:00:00 1970 From: Paolo Bonzini Subject: Re: [PATCH v5 4/7] kvm, mem-hotplug: Reload L1' apic access page on migration in vcpu_enter_guest(). Date: Thu, 11 Sep 2014 16:06:58 +0200 Message-ID: <5411AC82.4080005@redhat.com> References: <1410413886-32213-1-git-send-email-tangchen@cn.fujitsu.com> <1410413886-32213-5-git-send-email-tangchen@cn.fujitsu.com> <541169AD.6060908@redhat.com> <20140911101200.GF25317@minantech.com> <54117DB4.307@redhat.com> <20140911113051.GG25317@minantech.com> <54119E01.9000908@redhat.com> <20140911135956.GC26540@minantech.com> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Cc: Tang Chen , mtosatti@redhat.com, nadav.amit@gmail.com, jan.kiszka@web.de, kvm@vger.kernel.org, laijs@cn.fujitsu.com, isimatu.yasuaki@jp.fujitsu.com, guz.fnst@cn.fujitsu.com, linux-kernel@vger.kernel.org To: Gleb Natapov Return-path: In-Reply-To: <20140911135956.GC26540@minantech.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: kvm.vger.kernel.org Il 11/09/2014 15:59, Gleb Natapov ha scritto: > > Suppose vmcs01->APIC_ACCESS_ADDR = 0xf000. During L2 entry > vmcs02->APIC_ACCESS_ADDR is set to 0xf000 too (by prepare_vmcs02). Now > 0xf000 is migrated to 0x8000, mmu notifier is called, it forces vmexit, > but vcpu is in a guest mode so vmcs02->APIC_ACCESS_ADDR is never updated > to 0x8000 because of "if (!is_guest_mode(vcpu))" check. So what am I > missing here? Right, guest mode isn't left as soon as you execute nested_vmx_vmexit, because this isn't an L2->L1 exit. So we need an "else" for that "if (!is_guest_mode(vcpu))", in which case the hpa is ignored and vmcs12->apic_access_addr is used instead? Paolo