From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <SRS0=8dav=5Y=vger.kernel.org=linux-kernel-owner@kernel.org>
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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS,
	MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no 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 889C7C2BA2B
	for <linux-kernel@archiver.kernel.org>; Wed,  8 Apr 2020 23:14:24 +0000 (UTC)
Received: from vger.kernel.org (vger.kernel.org [209.132.180.67])
	by mail.kernel.org (Postfix) with ESMTP id 6575A2078E
	for <linux-kernel@archiver.kernel.org>; Wed,  8 Apr 2020 23:14:24 +0000 (UTC)
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
        id S1726598AbgDHXOX (ORCPT
        <rfc822;linux-kernel@archiver.kernel.org>);
        Wed, 8 Apr 2020 19:14:23 -0400
Received: from Galois.linutronix.de ([193.142.43.55]:50960 "EHLO
        Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org
        with ESMTP id S1726504AbgDHXOW (ORCPT
        <rfc822;linux-kernel@vger.kernel.org>);
        Wed, 8 Apr 2020 19:14:22 -0400
Received: from p5de0bf0b.dip0.t-ipconnect.de ([93.224.191.11] helo=nanos.tec.linutronix.de)
        by Galois.linutronix.de with esmtpsa (TLS1.2:DHE_RSA_AES_256_CBC_SHA256:256)
        (Exim 4.80)
        (envelope-from <tglx@linutronix.de>)
        id 1jMJtW-0005pC-UV; Thu, 09 Apr 2020 01:14:08 +0200
Received: by nanos.tec.linutronix.de (Postfix, from userid 1000)
        id 7616D101150; Thu,  9 Apr 2020 01:14:06 +0200 (CEST)
From:   Thomas Gleixner <tglx@linutronix.de>
To:     Vivek Goyal <vgoyal@redhat.com>
Cc:     Paolo Bonzini <pbonzini@redhat.com>,
        Sean Christopherson <sean.j.christopherson@intel.com>,
        Andy Lutomirski <luto@amacapital.net>,
        Peter Zijlstra <peterz@infradead.org>,
        Andy Lutomirski <luto@kernel.org>,
        LKML <linux-kernel@vger.kernel.org>, X86 ML <x86@kernel.org>,
        kvm list <kvm@vger.kernel.org>, stable <stable@vger.kernel.org>
Subject: Re: [PATCH v2] x86/kvm: Disable KVM_ASYNC_PF_SEND_ALWAYS
In-Reply-To: <875ze9r304.fsf@nanos.tec.linutronix.de>
References: <875ze9r304.fsf@nanos.tec.linutronix.de>
Date:   Thu, 09 Apr 2020 01:14:06 +0200
Message-ID: <87369dr2o1.fsf@nanos.tec.linutronix.de>
MIME-Version: 1.0
Content-Type: text/plain
X-Linutronix-Spam-Score: -1.0
X-Linutronix-Spam-Level: -
X-Linutronix-Spam-Status: No , -1.0 points, 5.0 required,  ALL_TRUSTED=-1,SHORTCIRCUIT=-0.0001
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

Thomas Gleixner <tglx@linutronix.de> writes:
> Vivek Goyal <vgoyal@redhat.com> writes:
>
> and the host completion injection which handles the queued completion
> when guest IF=0 does:

obviously IF=1 ...

>
>         struct ve_page *vp = vcpu->ve_page;
>
>         vp->host_current = idx;
>         inject_ve_complete(vcpu);
>
> The guest completion does:
>
>         struct ve_page *vp = this_cpu_ptr(&ve_page);
>         struct ve_info *info;
>
>         info = vp->info + vp->host_current;
>         rcuwait_wake_up(&info->wait);
>
> There are a bunch of life time issues to think about (not rocket
> science), but you get the idea.
>
> Thanks,
>
>         tglx