From mboxrd@z Thu Jan  1 00:00:00 1970
From: Paolo Bonzini <pbonzini@redhat.com>
Subject: Re: [PATCH 2/4] KVM: nVMX: Require immediate-exit when event
 reinjected to L2 and L1 event pending
Date: Sat, 11 Nov 2017 00:26:10 +0100
Message-ID: <1585ee8f-2783-028f-caee-f8116a080fcc@redhat.com>
References: <1509890866-8736-1-git-send-email-liran.alon@oracle.com>
 <1509890866-8736-3-git-send-email-liran.alon@oracle.com>
Mime-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Transfer-Encoding: 7bit
Cc: jmattson@google.com, idan.brown@oracle.com,
        Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
To: Liran Alon <liran.alon@oracle.com>, rkrcmar@redhat.com,
        kvm@vger.kernel.org
Return-path: <kvm-owner@vger.kernel.org>
Received: from mail-wr0-f182.google.com ([209.85.128.182]:48382 "EHLO
        mail-wr0-f182.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org
        with ESMTP id S1751038AbdKJX0O (ORCPT <rfc822;kvm@vger.kernel.org>);
        Fri, 10 Nov 2017 18:26:14 -0500
Received: by mail-wr0-f182.google.com with SMTP id 15so9845406wrb.5
        for <kvm@vger.kernel.org>; Fri, 10 Nov 2017 15:26:14 -0800 (PST)
In-Reply-To: <1509890866-8736-3-git-send-email-liran.alon@oracle.com>
Content-Language: en-US
Sender: kvm-owner@vger.kernel.org
List-ID: <kvm.vger.kernel.org>

On 05/11/2017 15:07, Liran Alon wrote:
> +	/*
> +	 * If we reinjected a previous event,
> +	 * don't consider a new pending event
> +	 */
> +	if (kvm_event_needs_reinjection(vcpu))
> +		return 0;
> +

Could you end up with

                        WARN_ON(vcpu->arch.exception.pending);

in vcpu_enter_guest after returning 0 here?

Maybe it would be safer to return a non-zero value so that the caller
sets req_immediate_exit = true.  But I haven't really thought through
the consequences.

Thanks,

Paolo