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=-2.0 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 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 2AE95C433DF for ; Fri, 10 Jul 2020 07:23:25 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id E9FCF2078D for ; Fri, 10 Jul 2020 07:23:24 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="Qx41BLG0" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E9FCF2078D Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:34972 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jtnNU-0000YX-9F for qemu-devel@archiver.kernel.org; Fri, 10 Jul 2020 03:23:24 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:45564) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jtnMv-00005U-Vd for qemu-devel@nongnu.org; Fri, 10 Jul 2020 03:22:49 -0400 Received: from us-smtp-1.mimecast.com ([207.211.31.81]:27068 helo=us-smtp-delivery-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1jtnMu-0005LR-HF for qemu-devel@nongnu.org; Fri, 10 Jul 2020 03:22:49 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1594365767; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=1LP15d34TouyszSVQjRJOSuUkVhVo3nqKacLbUvCJx0=; b=Qx41BLG0Nm9gemivRX69161axI4mzWyjapcGeJ7Xl0JkOG34nlYOE5+tJ5feAzyvncyo2F 7BgclXkuWEOsZ3zAuRsKQe4EjPk27BGaCdCmSdda6253DmnzhDhPCxJi/8YlZji0e8aJRu WX/zd0JqdnIIGMsyDJmGrclkK5syiOk= Received: from mail-wr1-f71.google.com (mail-wr1-f71.google.com [209.85.221.71]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-411-Ce0YOLg0MVq8mLD1m1x4vg-1; Fri, 10 Jul 2020 03:22:46 -0400 X-MC-Unique: Ce0YOLg0MVq8mLD1m1x4vg-1 Received: by mail-wr1-f71.google.com with SMTP id g14so4952186wrp.8 for ; Fri, 10 Jul 2020 00:22:45 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=1LP15d34TouyszSVQjRJOSuUkVhVo3nqKacLbUvCJx0=; b=lNi91HpKpsFh7lkyHCE6QAxN/m0nDEx0Ao78EmCan8Kan/tKbe71gDI3DITi88hRiT H7LqbONgznCVqXYAIGGiANtWn8CIpRTCehsBZjv1uhWYrXoWwlBUNp/z97WWCg0YG1bP imEbVX0ErF/fHHn1NiQX2E+c/DjqyXNrY48WyoFjh0Uo3+uF4IDdblhfKbsF8vgStrHt gbP7rQYCxSTW0A8Z8FBFDZsBaI60nVi5eoNzI/iwTTXUyeHNG+qXrvhFYAdM7AjFm1tF CnMFBzjeF/yyW9qQiFv1aEheJtsbR3tfUOmnILw71GuS9nwG+n7KyvNJLaEnJ07mPTUB K6Og== X-Gm-Message-State: AOAM530xcU2axfufHUlf/fHLuMZ7GbUZXXH6zc+wkTFVtyVq3mmHOpDb QgADAx0Uni03bCBBH6/XJjokTq9pcp/OmhnBRNBv54IrMEz2D4YjWuVJ1fXd6WXsKaIvWlvXZ44 7cBfMMJbpuYkejC8= X-Received: by 2002:a1c:5418:: with SMTP id i24mr3615693wmb.47.1594365765013; Fri, 10 Jul 2020 00:22:45 -0700 (PDT) X-Google-Smtp-Source: ABdhPJyJDfpsWJATF3x2k0/kUpiedr1e5eRuZK3mH9pswy5ELHGWFABftH17kpJ0ccpVvxQfTUOiuQ== X-Received: by 2002:a1c:5418:: with SMTP id i24mr3615668wmb.47.1594365764803; Fri, 10 Jul 2020 00:22:44 -0700 (PDT) Received: from ?IPv6:2001:b07:6468:f312:9541:9439:cb0f:89c? ([2001:b07:6468:f312:9541:9439:cb0f:89c]) by smtp.gmail.com with ESMTPSA id g14sm9517815wrw.83.2020.07.10.00.22.43 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 10 Jul 2020 00:22:44 -0700 (PDT) Subject: Re: [PATCH 2/2] x86/cpu: Handle GUEST_MAXPHYADDR < HOST_MAXPHYADDR for hosts that don't support it To: Eduardo Habkost , Jim Mattson References: <20200619155344.79579-1-mgamal@redhat.com> <20200619155344.79579-3-mgamal@redhat.com> <20200708171621.GA780932@habkost.net> <20200708172653.GL3229307@redhat.com> <20200709094415.yvdh6hsfukqqeadp@sirius.home.kraxel.org> <20200709191307.GH780932@habkost.net> From: Paolo Bonzini Message-ID: <79aa7955-6bc1-d8b2-fed0-48a0990d9dea@redhat.com> Date: Fri, 10 Jul 2020 09:22:42 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.9.0 MIME-Version: 1.0 In-Reply-To: <20200709191307.GH780932@habkost.net> Content-Language: en-US X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Received-SPF: pass client-ip=207.211.31.81; envelope-from=pbonzini@redhat.com; helo=us-smtp-delivery-1.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/07/09 23:35:58 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -30 X-Spam_score: -3.1 X-Spam_bar: --- X-Spam_report: (-3.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-1, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H3=-0.01, RCVD_IN_MSPIKE_WL=-0.01, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Guilherme Piccoli , Pedro Principeza , kvm list , libvir-list@redhat.com, Dann Frazier , mtosatti@redhat.com, "Dr. David Alan Gilbert" , Christian Ehrhardt , qemu-devel@nongnu.org, Gerd Hoffmann , =?UTF-8?Q?Daniel_P=2e_Berrang=c3=a9?= , Mohammed Gamal , Laszlo Ersek , fw@gpiccoli.net, rth@twiddle.net Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 09/07/20 21:13, Eduardo Habkost wrote: >> Doesn't this require intercepting MOV-to-CR3 when the guest is in PAE >> mode, so that the hypervisor can validate the high bits in the PDPTEs? > If the fix has additional overhead, is the additional overhead > bad enough to warrant making it optional? Most existing > GUEST_MAXPHYADDR < HOST_MAXPHYADDR guests already work today > without the fix. The problematic case is when host maxphyaddr is 52. That case wouldn't work at all without the fix. Paolo