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=-13.3 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,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 9ADFEC433B4 for ; Mon, 26 Apr 2021 19:44:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 54CE16141D for ; Mon, 26 Apr 2021 19:44:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241158AbhDZTpL (ORCPT ); Mon, 26 Apr 2021 15:45:11 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:32894 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S241107AbhDZTpC (ORCPT ); Mon, 26 Apr 2021 15:45:02 -0400 Received: from mail-pg1-x52c.google.com (mail-pg1-x52c.google.com [IPv6:2607:f8b0:4864:20::52c]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 056BAC061756 for ; Mon, 26 Apr 2021 12:44:12 -0700 (PDT) Received: by mail-pg1-x52c.google.com with SMTP id j7so31323949pgi.3 for ; Mon, 26 Apr 2021 12:44:12 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=q7xHJfw/FAhgI41nQLC+0GDChDTWCH6jbZ5uXcC3R7g=; b=uD57Nba9LUxaDOPNkbfoekPsVIVOiTlq7mL7WjBlh8kgRJ/axmZqfORTOxQoVro8lj 1qWWRxjQoLn4LIabeWCqyATH1tGLzIkFP93h0/KCwe3+lf7J/bNO+gSRvVjc4KubiynV 9whS8Wt1a5TRg4llRu/KD5emff1wMaXZvt0FC1e3xsEHqtU3FieP22PRvWUfvLtuCTCq yDZG2QlYpuT4i4SV17wJ6NjrRZ7nvQUlzLekhq9lZB8E7zspM54nwU5UkTlqyi0tajGW DjuC9MhNXNNuvuGK0kLXf1Jt0ktIb5rgGl7bAUa31PzLXXEfSPV0zy6ja4Xp+tCvcLBb 04cw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=q7xHJfw/FAhgI41nQLC+0GDChDTWCH6jbZ5uXcC3R7g=; b=jYF7Moy9UwldHZ3U5aHyoA/0BGerAiy9nUciSjqxxfgKcSrHP64H0rb4xGg5g7JGl0 8fO2ryKBjb1YZqA1dGx73qKn2aCEzE9ut144Fp50Az64HUEGFc9oipLiPSNb/LySjsKP BNzSMB3YWoU3MzUSyyVFwiZsxD8GM6vwXB0aCs8vzzI35Ch5T3VidGzxSiRcOw2rh+T/ JOg6L5L4lgmgG9c6nM4dJg8lr1PvsnYM5RkBRddCc6ce/w7UWnqTb1afz0QSCS+5Qokf vqOJ9EGDzimSNQdbF6FDpGehu8/xwyiCPTDEzSNHGwgQEI3xYp/txtAxV2eYMqErfFCF 29Jw== X-Gm-Message-State: AOAM530oEh/wms2xi7ykMHJ0GKj/FCiS5G6bMo5h379MG6pVN7nCZQkf AUWY2ZKku/Yrtc4lNwrO3w6CJA== X-Google-Smtp-Source: ABdhPJxY6NwR+9EgPKHRao08vemcJNCILzzyv2nNnxcZUp9VbbYuAUuxe6Go3zdHBHkkWjE81VzIQw== X-Received: by 2002:a63:ce03:: with SMTP id y3mr18095661pgf.414.1619466252386; Mon, 26 Apr 2021 12:44:12 -0700 (PDT) Received: from google.com (240.111.247.35.bc.googleusercontent.com. [35.247.111.240]) by smtp.gmail.com with ESMTPSA id x22sm12322889pgx.19.2021.04.26.12.44.11 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 26 Apr 2021 12:44:11 -0700 (PDT) Date: Mon, 26 Apr 2021 19:44:08 +0000 From: Sean Christopherson To: Vitaly Kuznetsov Cc: Paolo Bonzini , Wanpeng Li , Jim Mattson , Joerg Roedel , kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Reiji Watanabe Subject: Re: [PATCH v3 2/4] KVM: SVM: Clear MSR_TSC_AUX[63:32] on write Message-ID: References: <20210423223404.3860547-1-seanjc@google.com> <20210423223404.3860547-3-seanjc@google.com> <87k0opfmo9.fsf@vitty.brq.redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On Mon, Apr 26, 2021, Sean Christopherson wrote: > On Mon, Apr 26, 2021, Vitaly Kuznetsov wrote: > > Actually, shouldn't we just move wrmsrl() here? Assuming we're not sure > > how (and if) upper 32 bits are going to be used, it would probably make > > sense to not write them to the actual MSR... > > Argh. I got too clever in trying to minimize the patch deltas and "broke" this > intermediate patch. Once the user return framework is used, the result of > setting the MSR is checked before setting svm->tsc_aux, i.e. don't set the > virtual state if the real state could not be set. > > I'm very tempted to add yet another patch to this mess to do: > > if (wrmsrl_safe(MSR_TSC_AUX, data)) > return 1; > > svm->tsc_aux = data; > > And then this patch becomes: > > data = (u32)data; > > if (wrmsrl_safe(MSR_TSC_AUX, data)) > return 1; > > svm->tsc_aux = data; > > The above will also make patch 3 cleaner as it will preserve the ordering of > truncating data and the wrmsr. Ah, never mind, Paolo already pushed this to kvm/next with your above fix.