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=-3.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY,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 64F2CC2D0CE for ; Fri, 24 Jan 2020 23:13:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 352662075D for ; Fri, 24 Jan 2020 23:13:52 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="My4/aFYn" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729485AbgAXXNv (ORCPT ); Fri, 24 Jan 2020 18:13:51 -0500 Received: from mail-pg1-f196.google.com ([209.85.215.196]:44196 "EHLO mail-pg1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729299AbgAXXNv (ORCPT ); Fri, 24 Jan 2020 18:13:51 -0500 Received: by mail-pg1-f196.google.com with SMTP id x7so1872180pgl.11 for ; Fri, 24 Jan 2020 15:13:50 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:subject:from:in-reply-to:date:cc :content-transfer-encoding:message-id:references:to; bh=Dfg0/boBAQFvkeehLpElmfimf033PvO4iSo4QXoxHg4=; b=My4/aFYnUzlc6gwer7RI4Pxtk3U35mG5XYzaugWJ9DfTBQLxDA1N/sRhflPuTALvLy 8V6E+Al3NBolZOU6uwIvj8XytwFiXOec1mODNQenmgfFJ6teL/d+gXTqXu5qSHxqZgO9 fQtYPVnzDvX66bjMz2Eoo3hKml0s7it6PARXdFjiMDTgu6h8zK5xKdkBPZoWdH9ZcyWJ FXf0bewTClMpbeokFF8H68NYsgWOmB1EWzbrmN9hU917kbPeSg/WbFXskytHvpfJADH0 yUiadn+jlAJjQJ8wKlV3a2ugwjckU+qhstBQLXupoxTcJImwASd8dqAgI5LKr+KevheI nDWg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:subject:from:in-reply-to:date:cc :content-transfer-encoding:message-id:references:to; bh=Dfg0/boBAQFvkeehLpElmfimf033PvO4iSo4QXoxHg4=; b=qFBt3Nam8U7H3242+oUk/i9vLomYMoXMRk72+QCDRy6ChNOQKM/FxWmmhzofFaL7iJ jvGwcRgjuqk4nLjI1LHI+2UGkM1oLyxnXNx3H6mNW4xJ21hHlazGeuZMj60sxCZSASmx HmMR02f41GuVWwpCowgZrCDKNHHKUv8xlr7GD+ELK5v4vHJUiNvHtzlfV/MWuMOM9UtL GKxRzwkV9znChLGEbFscI20FTLMmD5Lrpo4L32wZ/ScsRNLbk+BLvsdkueo4vuOBQxV1 Sx3RIwUChNk28NDtZOXavqQRBoNrXU5b+qZVck0Q6jQobH+qv0TsrEMCR74wDEqkVGyF wkVw== X-Gm-Message-State: APjAAAWlrLxayzdyE17oF6MnqyuD71jRmOTlCHIE6SXn/wWgdMGLUcM4 nQGMJcsf8HWKTOa7EaL6fow= X-Google-Smtp-Source: APXvYqxOlF9LnKdCORsOMzAoo1TRTvEEBmiCyxjiem9LMyprqpC26FyXv0VYj+lQGTfNUTmjVOMSRA== X-Received: by 2002:aa7:96b0:: with SMTP id g16mr5217198pfk.99.1579907630109; Fri, 24 Jan 2020 15:13:50 -0800 (PST) Received: from [10.2.129.203] ([66.170.99.2]) by smtp.gmail.com with ESMTPSA id z30sm7795858pfq.154.2020.01.24.15.13.48 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 24 Jan 2020 15:13:49 -0800 (PST) Content-Type: text/plain; charset=utf-8 Mime-Version: 1.0 (Mac OS X Mail 13.0 \(3608.40.2.2.4\)) Subject: Re: [kvm-unit-tests PATCH v3] x86: Add RDTSC test From: Nadav Amit In-Reply-To: <20191202204356.250357-1-aaronlewis@google.com> Date: Fri, 24 Jan 2020 15:13:44 -0800 Cc: kvm list , Jim Mattson , Paolo Bonzini , Liran Alon Content-Transfer-Encoding: quoted-printable Message-Id: <4EFDEFF2-D1CD-4AF3-9EF8-5F160A4D93CD@gmail.com> References: <20191202204356.250357-1-aaronlewis@google.com> To: Aaron Lewis X-Mailer: Apple Mail (2.3608.40.2.2.4) Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org > On Dec 2, 2019, at 12:43 PM, Aaron Lewis = wrote: >=20 > Verify that the difference between a guest RDTSC instruction and the > IA32_TIME_STAMP_COUNTER MSR value stored in the VMCS12's VM-exit > MSR-store list is less than 750 cycles, 99.9% of the time. >=20 > 662f1d1d1931 ("KVM: nVMX: Add support for capturing highest observable = L2 TSC=E2=80=9D) >=20 > Signed-off-by: Aaron Lewis > Reviewed-by: Jim Mattson Running this test on bare-metal I get: Test suite: rdtsc_vmexit_diff_test FAIL: RDTSC to VM-exit delta too high in 117 of 100000 iterations Any idea why? Should I just play with the 750 cycles magic number?