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=-5.3 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,NICE_REPLY_A,PLING_QUERY,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 6312AC433E7 for ; Wed, 14 Oct 2020 08:28:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 00425212CC for ; Wed, 14 Oct 2020 08:28:13 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="IFVgoD7x" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727961AbgJNI2K (ORCPT ); Wed, 14 Oct 2020 04:28:10 -0400 Received: from us-smtp-delivery-124.mimecast.com ([63.128.21.124]:39129 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726554AbgJNI2J (ORCPT ); Wed, 14 Oct 2020 04:28:09 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1602664090; 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=MZZ9hnLpBSfUPYJnzrr8XxQqJEL/cKh9kdDj1jdY0mI=; b=IFVgoD7x1dyUKYaW6cxQSwHrhvoGn/NaVnSntmyO++GvCxCF+3BmqnOoeDTogb/Ddubw5v INOLSf00cWZVEKFO+c2FoIxZd5y+psr6XlK/2glOTBmTiKwOeKdnCNp6DgEWACrF4w6kbI CA88CpiSWdnkbSVMP/6qEM5ipnQ70rc= Received: from mail-ej1-f70.google.com (mail-ej1-f70.google.com [209.85.218.70]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-156-VIOHDOMsNtuK-UaEL6VBrA-1; Wed, 14 Oct 2020 04:28:09 -0400 X-MC-Unique: VIOHDOMsNtuK-UaEL6VBrA-1 Received: by mail-ej1-f70.google.com with SMTP id k23so892678ejx.0 for ; Wed, 14 Oct 2020 01:28:09 -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=MZZ9hnLpBSfUPYJnzrr8XxQqJEL/cKh9kdDj1jdY0mI=; b=bX8otfec3RAFMITPkwcLeP1w66kDQ/It419oGZaIEM679RI/RI/yX3sHhkYe54hFY5 llZEotQfxpAhAPBZ69mRhjPLfBvtaPO7PgRnW6XLkoWjE8si+EzP+KKNxmz5iAA3mZ6m eNsPKxgMdX76uXQcx/+Oumhaf25Nzk+HueX1y4s30XqZbdqpOaE7kCMzypPECF3KMoPP uVinmnx2WWWsZz1hs5fAgrioP97KuDJXLhAWRbomeAM1WVWRx+JsW9WIT2PJZT4ZYSRT Rxh2R9LYSt30O/5XWmps71or3bnTbDvesgRA2/4k9PyM/lPYJ2UPlHWyxgmPcqaj8s0i KNOw== X-Gm-Message-State: AOAM533Yjfw0p+qdkVdHWmpRfFMySKPLmTrcNKvk6uPr+U/+INsQUwkS BB1QW/KHuIIP7Imy9C/YxBAxJhA3/+o/xFbhTWlQAbRPUiwgDDHs6j2ywyoqUXJfrdVodB6w6y8 K6x98I7Tvaw7v X-Received: by 2002:a17:906:4e19:: with SMTP id z25mr4280724eju.44.1602664087760; Wed, 14 Oct 2020 01:28:07 -0700 (PDT) X-Google-Smtp-Source: ABdhPJzum0nzPjm+ya3l+65XT3fFEQPrAM01mV7i4zpCRmhZN3Ic86tRPf+B9dOifSlQiZiw5WPMGw== X-Received: by 2002:a17:906:4e19:: with SMTP id z25mr4280709eju.44.1602664087568; Wed, 14 Oct 2020 01:28:07 -0700 (PDT) Received: from ?IPv6:2001:b07:6468:f312:e5f7:db3b:55ea:7337? ([2001:b07:6468:f312:e5f7:db3b:55ea:7337]) by smtp.gmail.com with ESMTPSA id bu23sm1110816edb.69.2020.10.14.01.28.06 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 14 Oct 2020 01:28:06 -0700 (PDT) Subject: Re: Why guest physical addresses are not the same as the corresponding host virtual addresses in QEMU/KVM? Thanks! To: harry harry , Sean Christopherson Cc: Maxim Levitsky , qemu-devel@nongnu.org, mathieu.tarral@protonmail.com, stefanha@redhat.com, libvir-list@redhat.com, kvm@vger.kernel.org References: <47ead258320536d00f9f32891da3810040875aff.camel@redhat.com> <20201012165428.GD26135@linux.intel.com> <20201013045245.GA11344@linux.intel.com> <20201013070329.GC11344@linux.intel.com> From: Paolo Bonzini Message-ID: <626a8667-be00-96b7-f21d-1ec7648ee1e6@redhat.com> Date: Wed, 14 Oct 2020 10:28:05 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.11.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On 14/10/20 00:40, harry harry wrote: > Q1: Is there any file like ``/proc/pid/pagemap'' to record the > mappings between GPAs and HVAs in the host OS? No, there isn't. > Q2: Seems that there might be extra overhead (e.g., synchronization > between EPT tables and host regular page tables; maintaining extra > regular page tables and data structures), which is caused by the extra > translation between GPAs to HVAs via memslots. Why doesn't KVM > directly use GPAs as HVAs and leverage extended/nested page tables to > translate HVAs (i.e., GPAs) to HPAs? See my other answer. What you are saying is simply not possible. Paolo 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=-5.0 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A, PLING_QUERY,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 D1275C433DF for ; Wed, 14 Oct 2020 08:31:34 +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 404FA20BED for ; Wed, 14 Oct 2020 08:31:34 +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="IFVgoD7x" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 404FA20BED 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]:48874 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kScC5-0003xR-3q for qemu-devel@archiver.kernel.org; Wed, 14 Oct 2020 04:31:33 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:34136) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kSc8r-00014T-T4 for qemu-devel@nongnu.org; Wed, 14 Oct 2020 04:28:13 -0400 Received: from us-smtp-delivery-124.mimecast.com ([63.128.21.124]:48798) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1kSc8p-0008LT-O9 for qemu-devel@nongnu.org; Wed, 14 Oct 2020 04:28:13 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1602664090; 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=MZZ9hnLpBSfUPYJnzrr8XxQqJEL/cKh9kdDj1jdY0mI=; b=IFVgoD7x1dyUKYaW6cxQSwHrhvoGn/NaVnSntmyO++GvCxCF+3BmqnOoeDTogb/Ddubw5v INOLSf00cWZVEKFO+c2FoIxZd5y+psr6XlK/2glOTBmTiKwOeKdnCNp6DgEWACrF4w6kbI CA88CpiSWdnkbSVMP/6qEM5ipnQ70rc= Received: from mail-ej1-f71.google.com (mail-ej1-f71.google.com [209.85.218.71]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-194-NxNf8OLSP-6OxkJ5ytRoKA-1; Wed, 14 Oct 2020 04:28:09 -0400 X-MC-Unique: NxNf8OLSP-6OxkJ5ytRoKA-1 Received: by mail-ej1-f71.google.com with SMTP id c20so871274ejs.12 for ; Wed, 14 Oct 2020 01:28:08 -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=MZZ9hnLpBSfUPYJnzrr8XxQqJEL/cKh9kdDj1jdY0mI=; b=N2nnaHKY+EIGI/JdXmhkfcnaszeT0OEpR72t/kfEfvX7BeETUtLWWt+Ofs9i0fFxva V9cdtJ+mbFfOxvRf/ZprI4J+Hn9tKXNdGRPcWkOb2ffZAxmhEw+Q8sxiGlpSBZcXYFYU Wlx1JCWf5AIQfLrU/FXG9WOT0stKAHWpQ9qSaS7802KAZ8mDKCj+vrSEvsF9GXOKmxhA 4Ros2d55THKbKS4w2MGEgA0Zdf8rXJ4JUdJsoaIs/SvByWkD7Y1T16065wiZosLa0/8v T6bAjuui6sFZ/an9Mp1fD3F7qXiR0SRBzJFoQjpFY21qP95tNF1lXvjiHg9KFn510cB7 2UMw== X-Gm-Message-State: AOAM530+TZS6Xjw2JzdBT44nBDElfIfR+xzthdcwojgSPXoSm7ylq6m3 9NdHm03R8g9FpT10OLqrT1/5Xf7V39MOFmrJM8QqabTRcmT48knKtTz9LFN3aFJfA9KpXeshEn3 J3vqpudgwZRAydPc= X-Received: by 2002:a17:906:4e19:: with SMTP id z25mr4280719eju.44.1602664087759; Wed, 14 Oct 2020 01:28:07 -0700 (PDT) X-Google-Smtp-Source: ABdhPJzum0nzPjm+ya3l+65XT3fFEQPrAM01mV7i4zpCRmhZN3Ic86tRPf+B9dOifSlQiZiw5WPMGw== X-Received: by 2002:a17:906:4e19:: with SMTP id z25mr4280709eju.44.1602664087568; Wed, 14 Oct 2020 01:28:07 -0700 (PDT) Received: from ?IPv6:2001:b07:6468:f312:e5f7:db3b:55ea:7337? ([2001:b07:6468:f312:e5f7:db3b:55ea:7337]) by smtp.gmail.com with ESMTPSA id bu23sm1110816edb.69.2020.10.14.01.28.06 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 14 Oct 2020 01:28:06 -0700 (PDT) Subject: Re: Why guest physical addresses are not the same as the corresponding host virtual addresses in QEMU/KVM? Thanks! To: harry harry , Sean Christopherson References: <47ead258320536d00f9f32891da3810040875aff.camel@redhat.com> <20201012165428.GD26135@linux.intel.com> <20201013045245.GA11344@linux.intel.com> <20201013070329.GC11344@linux.intel.com> From: Paolo Bonzini Message-ID: <626a8667-be00-96b7-f21d-1ec7648ee1e6@redhat.com> Date: Wed, 14 Oct 2020 10:28:05 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.11.0 MIME-Version: 1.0 In-Reply-To: Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=pbonzini@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Received-SPF: pass client-ip=63.128.21.124; envelope-from=pbonzini@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/10/14 03:37:33 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -19 X-Spam_score: -2.0 X-Spam_bar: -- X-Spam_report: (-2.0 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, NICE_REPLY_A=-0.001, PLING_QUERY=0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H5=0.001, RCVD_IN_MSPIKE_WL=0.001, 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: kvm@vger.kernel.org, libvir-list@redhat.com, qemu-devel@nongnu.org, Maxim Levitsky , mathieu.tarral@protonmail.com, stefanha@redhat.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 14/10/20 00:40, harry harry wrote: > Q1: Is there any file like ``/proc/pid/pagemap'' to record the > mappings between GPAs and HVAs in the host OS? No, there isn't. > Q2: Seems that there might be extra overhead (e.g., synchronization > between EPT tables and host regular page tables; maintaining extra > regular page tables and data structures), which is caused by the extra > translation between GPAs to HVAs via memslots. Why doesn't KVM > directly use GPAs as HVAs and leverage extended/nested page tables to > translate HVAs (i.e., GPAs) to HPAs? See my other answer. What you are saying is simply not possible. Paolo