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=-8.4 required=3.0 tests=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 E187BC433DF for ; Wed, 8 Jul 2020 23:07:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A881A20772 for ; Wed, 8 Jul 2020 23:07:35 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="sJRVXB32" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726208AbgGHXHf (ORCPT ); Wed, 8 Jul 2020 19:07:35 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45768 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726044AbgGHXHe (ORCPT ); Wed, 8 Jul 2020 19:07:34 -0400 Received: from mail-io1-xd43.google.com (mail-io1-xd43.google.com [IPv6:2607:f8b0:4864:20::d43]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0B234C061A0B for ; Wed, 8 Jul 2020 16:07:34 -0700 (PDT) Received: by mail-io1-xd43.google.com with SMTP id a12so308365ion.13 for ; Wed, 08 Jul 2020 16:07:34 -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=mLYrBq3kxB014w6k6aADAiZibvi7Dst0ESJua5jQQNY=; b=sJRVXB32XkrmmGEaOsRIlIB/HpaKnueVfCkMoHS/YNzdjH/n0Tclh76JVey8R6fLN+ oXxXplNryQZEYrT76NoPL/2uTXpSkOAsfzxFoA0q6QxV4wgZdl4dlz4zjODkXcy13r7h cDdraUgasl71YhUU+UWnbPjSEZrSnN1itiu4kDuQ643gDCXxyfspkUCYYlYiYw1M2yjH r/UnT1LcKrB9w/O+DLDgQKaAo1AibVZICMwrYbRN9cgZVFRR3w1ya2LGRKHs0FpIotCR EUJ0Hprrkd81/wQ/rv0i/HioF1HgWmRFU6+n7SoSz30ROQGHLUEGhhO+mh/KzOQnl+Dl geHw== 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=mLYrBq3kxB014w6k6aADAiZibvi7Dst0ESJua5jQQNY=; b=Bs3EQFl3H3kZme5d105yvwSuCrVR9sAtm1pbhNmg7aG/1oKnISwSuEQUDwSgU+YoIo vMyWmbu7PKREnZeZ07QdMbhihcjX+AZWo+qzSjYUcHl+poD+SLq+rGxfXp+wpJqL1j7Q kNZccRbieutuz4rcg2Izky2tLAu8m2oxNeZKrX5jYnmSf5m+JwAaVtJIu6wG49WmQvwe phvfHt46BnS5q6RfcEWHpU1cI6p02uVgyG0ayo5bpewELHgQ9+bvgXPikzGu6/a5ojCx 7pb8qBSAwsHnwEBRG9dUpTlbfOVy5oLtd8+qZFXbbJdJlPFexC3r+HLkyS9Lojimqd2y E3WQ== X-Gm-Message-State: AOAM531Bh7tgsXCNAVjsHOCROh142Hx3Ej3TmYzUVi/0YamqvuVHgwcl XolBB2rdtcDk8d+UMoLQFAQ/VjZWEccgDgBVoUpmig== X-Google-Smtp-Source: ABdhPJwcOtdxUY9jBFzMMb2HfZvedSzRz0uiZZyP30stGRujyKaWgdXSujNfDwB0ckjRO+78c3w3TdPmecn5ZwuyYIM= X-Received: by 2002:a02:c785:: with SMTP id n5mr70055073jao.75.1594249653086; Wed, 08 Jul 2020 16:07:33 -0700 (PDT) MIME-Version: 1.0 References: <1594168797-29444-1-git-send-email-krish.sadhukhan@oracle.com> <1594168797-29444-3-git-send-email-krish.sadhukhan@oracle.com> <699b4ea4-d8df-e098-8f5c-3abe8e4c138c@redhat.com> In-Reply-To: From: Jim Mattson Date: Wed, 8 Jul 2020 16:07:22 -0700 Message-ID: Subject: Re: [PATCH 2/3 v4] KVM: nSVM: Check that MBZ bits in CR3 and CR4 are not set on vmrun of nested guests To: Krish Sadhukhan Cc: Paolo Bonzini , kvm list Content-Type: text/plain; charset="UTF-8" Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On Wed, Jul 8, 2020 at 3:51 PM Krish Sadhukhan wrote: > Just curious about using LME instead of LMA. According to APM, > > " The processor behaves as a 32-bit x86 processor in all respects > until long mode is activated, even if long mode is enabled. None of the > new 64-bit data sizes, addressing, or system aspects available in long > mode can be used until EFER.LMA=1." > > > Is it possible that L1 sets LME, but not LMA, in L2's VMCS and this > code will execute even if the processor is not in long-mode ? No. EFER.LMA is not modifiable through software. It is always "EFER.LME != 0 && CR0.PG != 0."