From mboxrd@z Thu Jan 1 00:00:00 1970 From: Radim =?utf-8?B?S3LEjW3DocWZ?= Subject: Re: [PATCH v2 3/4] KVM: async_pf: Force a nested vmexit if the injected #PF is async_pf Date: Fri, 16 Jun 2017 15:37:02 +0200 Message-ID: <20170616133702.GA6360@potion> References: <1497493615-18512-1-git-send-email-wanpeng.li@hotmail.com> <1497493615-18512-4-git-send-email-wanpeng.li@hotmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org, Paolo Bonzini , Wanpeng Li To: Wanpeng Li Return-path: Content-Disposition: inline In-Reply-To: <1497493615-18512-4-git-send-email-wanpeng.li@hotmail.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: kvm.vger.kernel.org 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. Thanks.