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=-3.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED 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 E05AEC433B4 for ; Sun, 11 Apr 2021 16:57:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B54FA610A7 for ; Sun, 11 Apr 2021 16:57:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235914AbhDKQ5l (ORCPT ); Sun, 11 Apr 2021 12:57:41 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57202 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233514AbhDKQ5i (ORCPT ); Sun, 11 Apr 2021 12:57:38 -0400 Received: from mail-pf1-x429.google.com (mail-pf1-x429.google.com [IPv6:2607:f8b0:4864:20::429]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 23450C061574 for ; Sun, 11 Apr 2021 09:57:22 -0700 (PDT) Received: by mail-pf1-x429.google.com with SMTP id c17so7621264pfn.6 for ; Sun, 11 Apr 2021 09:57:22 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amacapital-net.20150623.gappssmtp.com; s=20150623; h=content-transfer-encoding:from:mime-version:subject:date:message-id :references:cc:in-reply-to:to; bh=SijJqZ5EqSxizfZ+1rajM+6jINBOobyy+KI6KXX4/IQ=; b=gk8wFRtZrKTFaG200r2SZPxyKdvmPdjhP3AhbhPxY11DJfaBbVOya7bkOSrTDNLJ0m XQctnrzqO2AVCogR5lIKFs/Lx98yAW05yo0Cau2AvrIkmMb29lj9XCUFLuN6vR8Sk1Ib P2VOv08r6pJbVoaHsVwLM1KDgZ7lhBC5hXnVO1qK3wHhYdhe8dmomwLSFGC34Oe2C/QK kQOZEjhaOXYtJ3ZSRvRdpLXNIjqXRGjhdRUITaNmen1jxmZEXRJdwBtT3nGzDkIcH6fv EFXm/s/Sv3i5yH9E4har5kYj+9sWuXXDrv56ZlNCBEKrkNuuat2Fek8Xcn1u36aIVsb7 Ccrw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:content-transfer-encoding:from:mime-version :subject:date:message-id:references:cc:in-reply-to:to; bh=SijJqZ5EqSxizfZ+1rajM+6jINBOobyy+KI6KXX4/IQ=; b=YU2H8rnnCXnrFZ8wVFBcudlJtn9VhcfFkb48VqmNB3tES0i81Y/Zl5UgEQslkn77j5 SrzuKZ+sP51Qw914T6FmuHUEbcWOAydyzqF65kjN/hH383LV7Hh4a/yAPabgUdBosEmv f4br19NrGobFXJyaql56wpZMCruh00TjphkQV8tJKXxZNcwW/eVrj7St5PL3U9Ml1S5G DHkJHFoCg9jK32QaIRMM3LTTBFo+Wts43NYFREWqYleJhHwBp/3yyUz66F9LmNUgh7H0 Lfn6WrbEh0diJMv/wm/mr1Bo9W5nyk7TMgmz5ORXfMzc3pxPiFlowLyrNmlTXzgtcX9q VIcg== X-Gm-Message-State: AOAM531OKEtSgQ03+tkYnMOvSx5FGNqw+hYMI83D7naDED4l52ikgSit Kle8Gy6L5zxJBC3FEIXExoD9LTTySBWMteM1 X-Google-Smtp-Source: ABdhPJzwZLGRq8AyHKQoaaJ0jr16lmZwPkkTBKOb5RS6SwMMChPL4mmBTVHfPU7WOP26EYgQf1CWXA== X-Received: by 2002:a62:e70e:0:b029:245:3a00:5720 with SMTP id s14-20020a62e70e0000b02902453a005720mr15962206pfh.0.1618160241499; Sun, 11 Apr 2021 09:57:21 -0700 (PDT) Received: from ?IPv6:2601:646:c200:1ef2:590d:de8e:40a2:50b9? ([2601:646:c200:1ef2:590d:de8e:40a2:50b9]) by smtp.gmail.com with ESMTPSA id kk6sm8438580pjb.51.2021.04.11.09.57.20 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Sun, 11 Apr 2021 09:57:20 -0700 (PDT) Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable From: Andy Lutomirski Mime-Version: 1.0 (1.0) Subject: Re: [PATCH] x86/msr: Block writes to certain MSRs unconditionally Date: Sun, 11 Apr 2021 09:57:20 -0700 Message-Id: References: <20210411164342.GL3762101@tassilo.jf.intel.com> Cc: Borislav Petkov , Thomas Gleixner , Feng Tang , Ingo Molnar , "H . Peter Anvin" , Peter Zijlstra , X86 ML , LKML , "Zhang, Rui" , "Kleen, Andi" , Dave Hansen , Len Brown In-Reply-To: <20210411164342.GL3762101@tassilo.jf.intel.com> To: Andi Kleen X-Mailer: iPhone Mail (18D70) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > On Apr 11, 2021, at 9:43 AM, Andi Kleen wrote: >=20 > =EF=BB=BF >>=20 >> I have actually seen real user programs poke MSR_SYSCALL_MASK. >=20 > Hmm, what was the use case? >=20 >=20 Working around a kernel bug. The workaround only worked on AMD systems. Th= e correct solution was to fix the kernel bug, not poke MSRs.=