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 X-Spam-Level: X-Spam-Status: No, score=-7.0 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,RCVD_ILLEGAL_IP, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 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 DADA0C388F2 for ; Tue, 3 Nov 2020 06:12:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id AA6B52227F for ; Tue, 3 Nov 2020 06:12:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727053AbgKCGMr (ORCPT ); Tue, 3 Nov 2020 01:12:47 -0500 Received: from mga18.intel.com ([134.134.136.126]:42433 "EHLO mga18.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725958AbgKCGMr (ORCPT ); Tue, 3 Nov 2020 01:12:47 -0500 IronPort-SDR: jESKfE7+rU7U9IVR1F60q5nifyN4rCL+8w7GYh2/zqfm+1Qct23J2JxY9joSiT3a76W5f1LycO RWGRdBkk7ndQ== X-IronPort-AV: E=McAfee;i="6000,8403,9793"; a="156784134" X-IronPort-AV: E=Sophos;i="5.77,447,1596524400"; d="scan'208";a="156784134" X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga004.fm.intel.com ([10.253.24.48]) by orsmga106.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 02 Nov 2020 22:12:46 -0800 IronPort-SDR: xNIyDGLfoFK7i4p3oARDq1lrrWYtrHxt+zWGPYWrnjYPZMV0pMjBM4ajqmiHH9yNMOpDWTq8NO fl+0TvZJdMpg== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.77,447,1596524400"; d="scan'208";a="353094900" Received: from shzintpr02.sh.intel.com (HELO [0.0.0.0]) ([10.109.19.68]) by fmsmga004.fm.intel.com with ESMTP; 02 Nov 2020 22:12:43 -0800 Subject: Re: [PATCH] KVM: VMX: Enable Notify VM exit To: Jim Mattson Cc: Paolo Bonzini , Sean Christopherson , Vitaly Kuznetsov , Wanpeng Li , Joerg Roedel , Thomas Gleixner , Ingo Molnar , Borislav Petkov , "H . Peter Anvin" , the arch/x86 maintainers , kvm list , LKML , Xiaoyao Li References: <20201102061445.191638-1-tao3.xu@intel.com> From: Tao Xu Message-ID: Date: Tue, 3 Nov 2020 14:12:42 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On 11/3/20 6:53 AM, Jim Mattson wrote: > On Sun, Nov 1, 2020 at 10:14 PM Tao Xu wrote: >> >> There are some cases that malicious virtual machines can cause CPU stuck >> (event windows don't open up), e.g., infinite loop in microcode when >> nested #AC (CVE-2015-5307). No event window obviously means no events, >> e.g. NMIs, SMIs, and IRQs will all be blocked, may cause the related >> hardware CPU can't be used by host or other VM. >> >> To resolve those cases, it can enable a notify VM exit if no >> event window occur in VMX non-root mode for a specified amount of >> time (notify window). >> >> Expose a module param for setting notify window, default setting it to >> the time as 1/10 of periodic tick, and user can set it to 0 to disable >> this feature. >> >> TODO: >> 1. The appropriate value of notify window. >> 2. Another patch to disable interception of #DB and #AC when notify >> VM-Exiting is enabled. >> >> Co-developed-by: Xiaoyao Li >> Signed-off-by: Tao Xu >> Signed-off-by: Xiaoyao Li > > Do you have test cases? > Not yet, because we are waiting real silicon to do some test. I should add RFC next time before I test it in hardware.