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=-18.3 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_IN_DEF_DKIM_WL autolearn=unavailable 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 EFAF4C433ED for ; Wed, 5 May 2021 04:28:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C6F1D610E6 for ; Wed, 5 May 2021 04:28:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231621AbhEEE2n (ORCPT ); Wed, 5 May 2021 00:28:43 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46096 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231326AbhEEE2a (ORCPT ); Wed, 5 May 2021 00:28:30 -0400 Received: from mail-pf1-x42b.google.com (mail-pf1-x42b.google.com [IPv6:2607:f8b0:4864:20::42b]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1FA62C0613ED for ; Tue, 4 May 2021 21:27:10 -0700 (PDT) Received: by mail-pf1-x42b.google.com with SMTP id q2so1058518pfh.13 for ; Tue, 04 May 2021 21:27:10 -0700 (PDT) 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 :cc; bh=AkdJ7jdjHyuclShdANsqX7WPCnDkiVjMoelEcVTWBS0=; b=gR3LsznuyMIGgTZilvyx0JbzPUtgRaDl77q4aHnJG9jj2xRpGmUuKNGJmmDri8x6AB 1rx+OC3k+00tTkLIB0hsHQr2xUbgzHtK1opdiINI1vQ1MRP1Zt9ppArBgVelELnXR2UT VKjYZuOFWLL10Q6ZgngjkAfpOQaYSId/h3eJ3UOTMxiLVycyZrQ6uzZYv1QWVdwp2X1Y UVgku59UHziHV0a/0Ukn9h8lWrJ0tMc/u8iqfVnV/a7jsZxhto9jRLq+A0GlU7ib+oGP 9oX5E8rMCfiMYzBJe1ttxKAvMxK3fdGoIZDfmPLXdNqYp3wl7+HQtoofT7PoZrGXv65c mIDQ== 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=AkdJ7jdjHyuclShdANsqX7WPCnDkiVjMoelEcVTWBS0=; b=oum5PFzbtMw5FXyVqzw9RfYMF42wjYd9y/xKt4fm3zY9HZiyNl/lTYV6pCT/GxCwqh 6KqEiQ8+xnU8+nj2iOEAOjt1BGgExAVOB476cVVt/9SyApEc9FhHEWZAdPOlmmO+jJlJ cHn3FTfdPW8uUZH01xdaKA2dJjzcyrXbVEA/evsWrtX3wUsfwo/VqNoWkufS1BAzwrkj 3+UMC7EGGiY8gNdP+14UDnh5PVdyrrwRvBAfqQYpzrO7CS3LMr6ROZP08IGbS+C5nexP uCjP4k57gkkzJsJU5sSgPMJDM//Vq+M7cTQQLSFfXQ6ijStMusxeMy80uxCHiEzrDuO6 BDrw== X-Gm-Message-State: AOAM532x0OPcE8/R5U0MSVCcj3f9QQBI4/IMdt/wli5lFR8Czm7RVdAU ZLdkKrhEwPcyPZZE3Rj6EMJ+j9H2seYBI4mGDR9sng== X-Google-Smtp-Source: ABdhPJza8kErNiYiPhF4FsjxuCaUWp/dAsMXwZIhcTVBemm9n0WZjL+SoMALzGDgzOMRk8qkAZVeoJ4Cn6BCROM7Soc= X-Received: by 2002:a63:4f50:: with SMTP id p16mr26300372pgl.40.1620188829494; Tue, 04 May 2021 21:27:09 -0700 (PDT) MIME-Version: 1.0 References: <20210504171734.1434054-1-seanjc@google.com> <20210504171734.1434054-4-seanjc@google.com> In-Reply-To: <20210504171734.1434054-4-seanjc@google.com> From: Reiji Watanabe Date: Tue, 4 May 2021 21:26:53 -0700 Message-ID: Subject: Re: [PATCH 03/15] KVM: SVM: Inject #UD on RDTSCP when it should be disabled in the guest To: Sean Christopherson Cc: Paolo Bonzini , Vitaly Kuznetsov , Wanpeng Li , Jim Mattson , Joerg Roedel , kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Xiaoyao Li Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, May 4, 2021 at 10:17 AM Sean Christopherson wrote: > > Intercept RDTSCP to inject #UD if RDTSC is disabled in the guest. > > Note, SVM does not support intercepting RDPID. Unlike VMX's > ENABLE_RDTSCP control, RDTSCP interception does not apply to RDPID. This > is a benign virtualization hole as the host kernel (incorrectly) sets > MSR_TSC_AUX if RDTSCP is supported, and KVM loads the guest's MSR_TSC_AUX > into hardware if RDTSCP is supported in the host, i.e. KVM will not leak > the host's MSR_TSC_AUX to the guest. > > But, when the kernel bug is fixed, KVM will start leaking the host's > MSR_TSC_AUX if RDPID is supported in hardware, but RDTSCP isn't available > for whatever reason. This leak will be remedied in a future commit. > > Fixes: 46896c73c1a4 ("KVM: svm: add support for RDTSCP") > Cc: stable@vger.kernel.org > Signed-off-by: Sean Christopherson Reviewed-by: Reiji Watanabe