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=-5.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING, SPF_HELO_NONE,SPF_PASS autolearn=ham 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 C3317C31E44 for ; Wed, 12 Jun 2019 02:19:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 97CA920883 for ; Wed, 12 Jun 2019 02:19:32 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="OkEWnRO7" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2408405AbfFLCTb (ORCPT ); Tue, 11 Jun 2019 22:19:31 -0400 Received: from mail-oi1-f195.google.com ([209.85.167.195]:44398 "EHLO mail-oi1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2405661AbfFLCTb (ORCPT ); Tue, 11 Jun 2019 22:19:31 -0400 Received: by mail-oi1-f195.google.com with SMTP id e189so10511146oib.11; Tue, 11 Jun 2019 19:19:31 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=wQDTufhWXmTclfVcFNb1jQ6kdGaN6gyHA/mYmZL80sY=; b=OkEWnRO7vl1Cn4QB1PZiP8eUmLStmLdSZZsd6x3jAtC+YTPd66WtvIhRvn52nZZswF ItyuQ1El0/W5v5RoZZdtLMmyb7Y0S8LxZhPCDmx/cFrenjJq2hRxGw3VrwyB5CG50ZI7 YnEZGS5hjxqbuzbXimbtWxsWRY4LLkpn5tqWe1Bz6SpYydBMaxDVncSOWkOxaHeO3TDx IZA4owuu0/Gd+5YLHzWgFue2PgJLLjscQ2TLKu89E3vNF29aC0tQIY1YRklpzXl6fZVf 7UYiq5jHvVDgK6DXqTvGhCXPh6EJYTfdfRLsZbaztk8pc3eeUZsfLvJJ9AecXaDFMcq2 D3rw== 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=wQDTufhWXmTclfVcFNb1jQ6kdGaN6gyHA/mYmZL80sY=; b=ZIdoytIPkoVp/GBnWDEdnQR2epOOwzIrqpXnvVrVbZ7tgOWKAkWi6vXSyQ2qnMX1KW sj9urc+jtzpOpjBC9CVknApN5RotQfnP/+6kzbbSQH1YgkAm02SrdpDi9TmldhwcAgpi ox7nmuG/9IxIiM9pFH3Yr/Rk6VG3xX8w+Qq1uHf3uUvP1y0nb948sU9FVnRTEbEyNCDY IS/FuQh2nWHEZ0M+F8yhSxqGndI9SihaHxi/JgdaCSpeu9M8fhulrtLlPeY70cmYS9HO JPHc6SqS6ybbA4Aqjkx5yPugP6MiawTBxWvmYlmev0TtGtqeNUVsvJeWffVsOWJCkcEF E80A== X-Gm-Message-State: APjAAAUuggm6N7LzQV1jSfo1ly9XRbvcS/DERZ9pB0skzoK0G5ENUEne D2LQ/O9OO9PgebJfTIpz651iHE2t3s92YPN/R58= X-Google-Smtp-Source: APXvYqxznTpSOFSgXuguROa+bMFdeyJBBYOGNflyVzIW59pLuKjzNA4upjNYPseua6q5L9J9eqW6qtywuWpd0Dyslr0= X-Received: by 2002:aca:3305:: with SMTP id z5mr15437298oiz.141.1560305970797; Tue, 11 Jun 2019 19:19:30 -0700 (PDT) MIME-Version: 1.0 References: <1558418814-6822-1-git-send-email-wanpengli@tencent.com> <1558418814-6822-2-git-send-email-wanpengli@tencent.com> <627e4189-3709-1fb2-a9bc-f1a577712fe0@redhat.com> In-Reply-To: From: Wanpeng Li Date: Wed, 12 Jun 2019 10:20:14 +0800 Message-ID: Subject: Re: [PATCH v2 2/3] KVM: X86: Provide a capability to disable cstate msr read intercepts To: Paolo Bonzini Cc: LKML , kvm , =?UTF-8?B?UmFkaW0gS3LEjW3DocWZ?= , Sean Christopherson , Liran Alon Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 11 Jun 2019 at 19:09, Paolo Bonzini wrote: > > On 11/06/19 09:38, Wanpeng Li wrote: > > MSR_CORE_C1_RES is unreadable except for ATOM platform, so I think we > > can avoid the complex logic to handle C1 now. :) > > I disagree. Linux uses it on all platforms is available, and virtual > machines that don't pass mwait through _only_ have C1, so it would be > less useful to have deep C-state residency MSRs and not C1 residency. Your design heavily depends on read host MSR_CORE_C1_RES for C1 residency msr emulation, however, the host MSR_CORE_C1_RES is unreadable. #rdmsr 0x660 rdmsr: CPU 0 cannot read MSR 0x00000660 Refer to turbostat codes, https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/tools/power/x86/turbostat/turbostat.c#n1335 C1 is derivated from other parameters. use_c1_residency_msr is true just for ATOM platform. Regards, Wanpeng Li