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=-14.3 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_IN_DEF_DKIM_WL 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 3B1AAC00A89 for ; Mon, 2 Nov 2020 22:54:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DCCB322384 for ; Mon, 2 Nov 2020 22:54:49 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="P6ng53Ed" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725913AbgKBWyA (ORCPT ); Mon, 2 Nov 2020 17:54:00 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43298 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725818AbgKBWyA (ORCPT ); Mon, 2 Nov 2020 17:54:00 -0500 Received: from mail-oi1-x243.google.com (mail-oi1-x243.google.com [IPv6:2607:f8b0:4864:20::243]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8AF98C061A47 for ; Mon, 2 Nov 2020 14:54:00 -0800 (PST) Received: by mail-oi1-x243.google.com with SMTP id t143so4824748oif.10 for ; Mon, 02 Nov 2020 14:54:00 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=gxMXOaWOcX7RWi2XohG/kNHvSy7AhpsjgRQW4jBaDgc=; b=P6ng53EdpuHBLplB221LcjZTmll1OcBSb7Gf0ID8ii2ONguufw8ilLp97H3Cgzxq+s WaeE7NEBHU8CEqXAQeVIjCGxqBgw+EzNDwnpEiloncZJrkHQ3V/gPqRvyMcVLJXtaFqN cEGBZGuow+HoX77Q/NJTmWor7xIJJIy0mTpLHUmGWDCuCxd8mHge6SGZJIbEmtTntV0Z tJaFzQrCJ9su2MsqE66AIkQb37McPrsPDjMjpU9Nez+liy0XYHmuvEc7drt3ilOsDTG5 2neXrfP+P9zYpBmkjez3Es+JgesMX93j8fo8GgKfRIDm3WTI9ziNayKZbsFuap5FOVlH ovCA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=gxMXOaWOcX7RWi2XohG/kNHvSy7AhpsjgRQW4jBaDgc=; b=kDJ5l25nXkPP9sMMZQLrFgusGoQWrIqHARC+2HNTJS+GJbge0mLs3h0Pl/uZFJtkDs OFK8r14BZ6imIOlPauSmNg5lVJ5uYjshYabzxOottLOiFniri36zdjwzxySArhCVXd4L wizXn9ZLQ9eeOn4sxgOlRydvkGxMllZSAlbkqGmwWlpGhyWa6ahxphEOaearZrugk0YR LmD6FQI7XZmBcBSzLubRaKO75UJ5mrAOIJvXdZO2GGplvGhjuP737YUC0DZnR6VOaDpz HmquqkoGHyXo9EY4xn34gcmfHYOZ4kKijliBW+YnDJ0Udq3VfV6ZttAEhrQiyeXBAN9+ r0cw== X-Gm-Message-State: AOAM533Q3eYVBfAIm+IR8nH+HwnLclmfDNbXKJcqvPLiSCcUZnSZXLpF t7RmAvuK3L1mUZC5yPEgiaxO+Vv98iR1K7897WQ2/w== X-Google-Smtp-Source: ABdhPJwiBRkyEJmNyWELvRc7Bv1J3jMYpYigUmhylzmxppC6VnYz3LwIszJXigYZDmgDvhshF0EBhX0xnHRT2G218gw= X-Received: by 2002:a54:4016:: with SMTP id x22mr283781oie.28.1604357639327; Mon, 02 Nov 2020 14:53:59 -0800 (PST) MIME-Version: 1.0 References: <20201102061445.191638-1-tao3.xu@intel.com> In-Reply-To: <20201102061445.191638-1-tao3.xu@intel.com> From: Jim Mattson Date: Mon, 2 Nov 2020 14:53:48 -0800 Message-ID: Subject: Re: [PATCH] KVM: VMX: Enable Notify VM exit To: Tao Xu 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 Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org 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?