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[23.128.96.18]) by mx.google.com with ESMTP id o60si15680286eda.61.2020.11.17.13.25.25; Tue, 17 Nov 2020 13:25:47 -0800 (PST) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18; Authentication-Results: mx.google.com; dkim=pass header.i=@google.com header.s=20161025 header.b=bh99XQeq; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=REJECT sp=REJECT dis=NONE) header.from=google.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727701AbgKQVXD (ORCPT + 99 others); Tue, 17 Nov 2020 16:23:03 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49780 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726536AbgKQVXD (ORCPT ); Tue, 17 Nov 2020 16:23:03 -0500 Received: from mail-io1-xd2f.google.com (mail-io1-xd2f.google.com [IPv6:2607:f8b0:4864:20::d2f]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 94C53C0613CF for ; Tue, 17 Nov 2020 13:23:01 -0800 (PST) Received: by mail-io1-xd2f.google.com with SMTP id u21so22712608iol.12 for ; Tue, 17 Nov 2020 13:23:01 -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; bh=WRD9K2m6dhhul0lisphy8QdJQFjcZsj68Hj+fomUoZM=; b=bh99XQeqcpnTkB8f+4cmAhV+F5bCR8QoaAb94TwgBqiQgmfhMjaufNypBq+aRmFQX0 hnJU1YMNc2FPDTKIULpJxqMygyUMGhMURazsLExa1n66uCvIcFNBuGq0HJgB6eK8XUIu KpPuW64aSuzMBNF2psjb5tTp99vIfMekPCYxEescloDNMCb3Eq1MqxRCcWoOmAjgPJ+B ZME/fG7IN96WqJVD8k7S6jYcL0KzVz7e0sJqIry2kIiDBUc2N2QsYlrG/bSI9aHRdGo7 hbUXoi1nDUrdDZnOjsLG2aT6tlNScXfYTsX/2C6yIr7tQvPxCYXZVjYJ8PHR+GDpB5P9 S1MQ== 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; bh=WRD9K2m6dhhul0lisphy8QdJQFjcZsj68Hj+fomUoZM=; b=CeG8oak2R2XX+tuoZxp9s9wJ2DAQCnj058oqynSYJUHjDa/Pvq81Mas3YQcH80gbt3 wfrWBwvIBv3qStcQHPhkQRJKI3HMLxPDCku3iLH1mg54m1yCMnz4PpdtxBJUQXiChvyx Te///mX6+WzZNtnAPE98nBmqRy5YuiN5bI9PIQ4tT0VyCaX6IWokD6CFTHFfhFpAYMdR 1iAOKZgUa3SPgcMEPyexFE/N80hcIBeqtk3nYImNTzVaT8o2UUm7Y0oYULN6f3Yo36aP bbfVeN6r8jf1IeLD5JC2/bKOpcyWZ57yW0kxiBY74qfBT8e9oEeCsosrjPWfuXvT6L4o SzSw== X-Gm-Message-State: AOAM532XijSt/hKxyHGd+EjjS20PV1n4oLeSf2ABsTXNaHZghPqS3+om qlSuif5y6GygClMeyrq2ecz76gViY9sLte8BctYkZw== X-Received: by 2002:a05:6638:1035:: with SMTP id n21mr5272928jan.107.1605648180707; Tue, 17 Nov 2020 13:23:00 -0800 (PST) MIME-Version: 1.0 References: <20200615063837.GA14668@zn.tnic> <20200714121955.GA2080@chrisdown.name> <20200714154728.GA3101@nazgul.tnic> <20200714160448.GC2080@chrisdown.name> <20201117210018.GA4247@weirdfishes> In-Reply-To: From: Matthew Garrett Date: Tue, 17 Nov 2020 13:22:49 -0800 Message-ID: Subject: Re: [PATCH -v2.1] x86/msr: Filter MSR writes To: Mathieu Chouquet-Stringer , Matthew Garrett , Chris Down , Borislav Petkov , Linux Kernel Mailing List , sean.j.christopherson@intel.com, tony.luck@intel.com, Linus Torvalds , "the arch/x86 maintainers" , kernel-team@fb.com, Len Brown Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Nov 17, 2020 at 1:21 PM Matthew Garrett wrote: > > On Tue, Nov 17, 2020 at 1:00 PM Mathieu Chouquet-Stringer > wrote: > > > I'm late to the party but it seems allowing MSR_IA32_ENERGY_PERF_BIAS > > has the downside of flagging the kernel as tainted without telling you > > why if you use something like x86_energy_perf_policy (from > > tools/power/x86/x86_energy_perf_policy) which itself is used by tuned. > > I initially pushed back against a kernel interface for > MSR_IA32_ENERGY_PERF_BIAS (cc: Len Brown, who tried mightily to > convince me I was wrong here) on the grounds that it was exporting an > implementation detail rather than providing a generic interface, and > that it was something that could be done via userland instead. I > thought we'd end up with more examples of similar functionality and > could tie it into something more reasonable - history has proven me > wrong on that. I think it's probably reasonable to dust off the driver > that Len submitted however many years ago and push that into the > kernel now. But ha ok based on Borislav's response it looks like someone's already done that.