Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754251AbdFPOZB (ORCPT ); Fri, 16 Jun 2017 10:25:01 -0400 Received: from mail-oi0-f65.google.com ([209.85.218.65]:34031 "EHLO mail-oi0-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753887AbdFPOY7 (ORCPT ); Fri, 16 Jun 2017 10:24:59 -0400 MIME-Version: 1.0 In-Reply-To: <20170616133702.GA6360@potion> References: <1497493615-18512-1-git-send-email-wanpeng.li@hotmail.com> <1497493615-18512-4-git-send-email-wanpeng.li@hotmail.com> <20170616133702.GA6360@potion> From: Wanpeng Li Date: Fri, 16 Jun 2017 22:24:58 +0800 Message-ID: Subject: Re: [PATCH v2 3/4] KVM: async_pf: Force a nested vmexit if the injected #PF is async_pf To: =?UTF-8?B?UmFkaW0gS3LEjW3DocWZ?= Cc: "linux-kernel@vger.kernel.org" , kvm , Paolo Bonzini , Wanpeng Li Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from quoted-printable to 8bit by mail.home.local id v5GEP6Xo015931 Content-Length: 1601 Lines: 37 2017-06-16 21:37 GMT+08:00 Radim Krčmář : > 2017-06-14 19:26-0700, Wanpeng Li: >> From: Wanpeng Li >> >> Add an async_page_fault field to vcpu->arch.exception to identify an async >> page fault, and constructs the expected vm-exit information fields. Force >> a nested VM exit from nested_vmx_check_exception() if the injected #PF >> is async page fault. >> >> Cc: Paolo Bonzini >> Cc: Radim Krčmář >> Signed-off-by: Wanpeng Li >> --- >> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c >> @@ -452,7 +452,11 @@ EXPORT_SYMBOL_GPL(kvm_complete_insn_gp); >> void kvm_inject_page_fault(struct kvm_vcpu *vcpu, struct x86_exception *fault) >> { >> ++vcpu->stat.pf_guest; >> - vcpu->arch.cr2 = fault->address; >> + vcpu->arch.exception.async_page_fault = fault->async_page_fault; > > I think we need to act as if arch.exception.async_page_fault was not > pending in kvm_vcpu_ioctl_x86_get_vcpu_events(). Otherwise, if we > migrate with pending async_page_fault exception, we'd inject it as a > normal #PF, which could confuse/kill the nested guest. > > And kvm_vcpu_ioctl_x86_set_vcpu_events() should clean the flag for > sanity as well. Do you mean we should add a field like async_page_fault to kvm_vcpu_events::exception, then saves arch.exception.async_page_fault to events->exception.async_page_fault through KVM_GET_VCPU_EVENTS and restores events->exception.async_page_fault to arch.exception.async_page_fault through KVM_SET_VCPU_EVENTS? Regards, Wanpeng Li