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=-11.4 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 036EEC433E3 for ; Fri, 10 Jul 2020 17:13:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D44B720674 for ; Fri, 10 Jul 2020 17:13:23 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="uXRgs8RX" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728002AbgGJRNU (ORCPT ); Fri, 10 Jul 2020 13:13:20 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41088 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727065AbgGJRNT (ORCPT ); Fri, 10 Jul 2020 13:13:19 -0400 Received: from mail-il1-x141.google.com (mail-il1-x141.google.com [IPv6:2607:f8b0:4864:20::141]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 40FC4C08C5DD for ; Fri, 10 Jul 2020 10:13:19 -0700 (PDT) Received: by mail-il1-x141.google.com with SMTP id a6so5651804ilq.13 for ; Fri, 10 Jul 2020 10:13:19 -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=84ZXCV8hDQ+R5ezHGlVeKRrDnq+BIKMBqF4O35I2mAU=; b=uXRgs8RXS68b0Quf5QIP7lY7g8JASh2hxqEYYRrQeMoIGtj9erXk5JTXrFVc6cFhyr bG1/VNQVX9SeKZvwO0E5XiApXK7A5wmbjBDhXvBFfah+DKBdg1KxeAeS5ihfy8M6F+Uj Oj/Ax225XjIZ+NeX7sgaKdlOYfov+ZZh+RHNd71U6LWc6Ysql3GrCDci50+q3cnR4Xa9 6QKuV7m2//VmHl/sZ7UYy0YYpZZtmUFNMVLwZ0I0WQfROWKprUXb0gtaeFvUyV5wIZrx v4OjT3xJta1onx8eUwTX7N9vq0bJwF/RoYaP6As9k7AhiYr6YgcBn2Gb9Z3GYtbeS5Qs leLA== 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=84ZXCV8hDQ+R5ezHGlVeKRrDnq+BIKMBqF4O35I2mAU=; b=N9MLQv0UPzpLty7/PQleSpRhBF+3UUIQtagSsD6sAiIrz2VI7igufcKVEjtIB6OKyH L/4voClGxUEe2xoEpLSdcUlBSffuurF/n/eAJNAlVlegXCTUmgKbtP01fxf2piLIdlh2 REYx1GQ39Vu3iDR/PaTOPbdy2iBt4+aT/Uu8ASwSA02NK3mcYlqdkYVzbsWQhvKgVDCK 72Zyv/vphUdGpeACt1V0hxxDm9bI+3s682hUHZXin0+2r5L0xHC7vR+DMDZfNmBbq4nb kER0pcriUwulsag2UyuuFCxQl2kiv3wTmHIOMJuXd859bIwZZQ1h8d5tBgi3dO1qZh+4 nSzQ== X-Gm-Message-State: AOAM533sxRK5uKKr0Q1T0p+SnZjsjZE8q1tMpDD8EQsgLAfSNxFB1Oek 8993AK+MRT8LvFf8LhBiPBreMZGVJKzirn7h5sxZM4mL X-Google-Smtp-Source: ABdhPJwBA5AirBckpFqBud4uPWIU+hnJlSHn3ByjqzmJ47BokabuqeNOCy1OQrj33SMvU88+SIo9y9H1TzuxucnwE7o= X-Received: by 2002:a92:b60a:: with SMTP id s10mr49715934ili.119.1594401198223; Fri, 10 Jul 2020 10:13:18 -0700 (PDT) MIME-Version: 1.0 References: <20200710154811.418214-1-mgamal@redhat.com> <0c892b1e-6fe6-2aa7-602e-f5fadc54c257@redhat.com> In-Reply-To: <0c892b1e-6fe6-2aa7-602e-f5fadc54c257@redhat.com> From: Jim Mattson Date: Fri, 10 Jul 2020 10:13:07 -0700 Message-ID: Subject: Re: [PATCH v3 0/9] KVM: Support guest MAXPHYADDR < host MAXPHYADDR To: Paolo Bonzini Cc: Mohammed Gamal , kvm list , LKML , Vitaly Kuznetsov , Sean Christopherson , Wanpeng Li , Joerg Roedel 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 Fri, Jul 10, 2020 at 10:06 AM Paolo Bonzini wrote: > > On 10/07/20 18:30, Jim Mattson wrote: > >> > >> This can be problem when having a mixed setup of machines with 5-level page > >> tables and machines with 4-level page tables, as live migration can change > >> MAXPHYADDR while the guest runs, which can theoretically introduce bugs. > > > > Huh? Changing MAXPHYADDR while the guest runs should be illegal. Or > > have I missed some peculiarity of LA57 that makes MAXPHYADDR a dynamic > > CPUID information field? > > Changing _host_ MAXPHYADDR while the guest runs, such as if you migrate > from a host-maxphyaddr==46 to a host-maxphyaddr==52 machine (while > keeping guest-maxphyaddr==46). Ah, but what does that have to do with LA57?