From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id B8BABC433FE for ; Fri, 25 Feb 2022 15:13:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241760AbiBYPOK (ORCPT ); Fri, 25 Feb 2022 10:14:10 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38154 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S241739AbiBYPOA (ORCPT ); Fri, 25 Feb 2022 10:14:00 -0500 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id CC045192F21 for ; Fri, 25 Feb 2022 07:13:26 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1645802005; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=ov22t1h+p3GE8LnI0EYb92eCXGx+vATLrydZwrAaric=; b=jVFGxTav7ApKUnbrctKnAsZv972tRvl+IdVR8pNys91g+UVoyfl3Liwkx7QcTcyO4hdjWS RodtKWeHJd2k9Fa0HyJVzOHMPy2AOI+Dbq8GG4qUsn5k30zg5hgUKAaFFmgoWHNaErsZc0 HQaUivDMfvm177Hl/NO1fhpRCyM5uAA= Received: from mail-wm1-f71.google.com (mail-wm1-f71.google.com [209.85.128.71]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-93-yeisX76iPjeAnlw9u5AmUQ-1; Fri, 25 Feb 2022 10:13:24 -0500 X-MC-Unique: yeisX76iPjeAnlw9u5AmUQ-1 Received: by mail-wm1-f71.google.com with SMTP id h206-20020a1c21d7000000b003552c13626cso1690196wmh.3 for ; Fri, 25 Feb 2022 07:13:23 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:message-id:date:mime-version:user-agent:subject :content-language:to:cc:references:from:in-reply-to :content-transfer-encoding; bh=ov22t1h+p3GE8LnI0EYb92eCXGx+vATLrydZwrAaric=; b=Sx7vo6c6c4IzEWNG4MHWrtSsKMnDHCZVwsXIWK9GVzjOSMl95yERqEqs2mUStiUBfA XMa6rJuSVBJPfU9eF74949ztzoHzPsJRfdZQqEnEKGYRYjtwxhre75alcrEgDsacGGXC NmfiS7pmldHbnAxqm6wehyuYr+9aruzxYqqxLA3L8ofCJ45grTTwkH5wYWF6w2fV53jS gVFYVSxstAyCwhzPya+KcJzwd3F/KY9euOMC3NChDMbzK5DKccIuyFEztzgBfaxdKFpm Cn3ZqsoxSI+glDwOyskzgsDPisuQzW7WPIsyh068zvdNvUD3gfNQvE7OlWF8A9AoTPd3 W5LA== X-Gm-Message-State: AOAM532FnH/yLcIDkbA2Gb+TkNv3jFANPQs4KxY5Gtp2T4R6Duv+/fHy U5s9Y+fOJ1dRkyc1waTwetePsxlYkO7t0leo7/LQzZnMRw44DwiFT1toen6JTf4vVVKs6sE5CKf OEF79rLKWPS2ErSOwqIMgmot9 X-Received: by 2002:a05:600c:34cf:b0:380:f514:dee1 with SMTP id d15-20020a05600c34cf00b00380f514dee1mr3089253wmq.5.1645802002924; Fri, 25 Feb 2022 07:13:22 -0800 (PST) X-Google-Smtp-Source: ABdhPJwDJ2C15TRsqqLZRDo4H+n1O6Fkpazg6veWu5whVVg5NXk90SmAcwX5kdNdrN9yZWucddmWZQ== X-Received: by 2002:a05:600c:34cf:b0:380:f514:dee1 with SMTP id d15-20020a05600c34cf00b00380f514dee1mr3089243wmq.5.1645802002719; Fri, 25 Feb 2022 07:13:22 -0800 (PST) Received: from ?IPV6:2001:b07:6468:f312:c8dd:75d4:99ab:290a? ([2001:b07:6468:f312:c8dd:75d4:99ab:290a]) by smtp.googlemail.com with ESMTPSA id m62-20020a1c2641000000b00380d0cff5f3sm6333003wmm.8.2022.02.25.07.13.21 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 25 Feb 2022 07:13:22 -0800 (PST) Message-ID: <7859e03f-10fa-dbc2-ed3c-5c09e62f9016@redhat.com> Date: Fri, 25 Feb 2022 16:13:21 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.5.0 Subject: Re: [PATCH v3] KVM: VMX: Enable Notify VM exit Content-Language: en-US To: Xiaoyao Li , Jim Mattson , Chenyi Qiang Cc: Sean Christopherson , Vitaly Kuznetsov , Wanpeng Li , Joerg Roedel , kvm@vger.kernel.org, linux-kernel@vger.kernel.org References: <20220223062412.22334-1-chenyi.qiang@intel.com> <88eb9a9a-fbe3-8e2c-02bd-4bdfc855b67f@intel.com> <6a839b88-392d-886d-836d-ca04cf700dce@intel.com> From: Paolo Bonzini In-Reply-To: <6a839b88-392d-886d-836d-ca04cf700dce@intel.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2/25/22 16:12, Xiaoyao Li wrote: >>>> >>> >>> I don't like the idea of making things up without notifying userspace >>> that this is fictional. How is my customer running nested VMs supposed >>> to know that L2 didn't actually shutdown, but L0 killed it because the >>> notify window was exceeded? If this information isn't reported to >>> userspace, I have no way of getting the information to the customer. >> >> Then, maybe a dedicated software define VM exit for it instead of >> reusing triple fault? >> > > Second thought, we can even just return Notify VM exit to L1 to tell L2 > causes Notify VM exit, even thought Notify VM exit is not exposed to L1. That might cause NULL pointer dereferences or other nasty occurrences. Paolo