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=-0.6 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 01AA4C433E0 for ; Tue, 26 May 2020 04:49:50 +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 B833D207ED for ; Tue, 26 May 2020 04:49:50 +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="QHQlDcDO" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B833D207ED 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]:41398 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jdRXC-0002rc-1L for qemu-devel@archiver.kernel.org; Tue, 26 May 2020 00:49:50 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:54870) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jdRWF-00023g-Tc for qemu-devel@nongnu.org; Tue, 26 May 2020 00:48:51 -0400 Received: from us-smtp-2.mimecast.com ([207.211.31.81]:50357 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 1jdRWE-0002g0-Fx for qemu-devel@nongnu.org; Tue, 26 May 2020 00:48:51 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1590468529; 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: in-reply-to:in-reply-to:references:references; bh=kTtIt+PGiXS7I6J5XlPeQ5fiJGg8Ep4BqurDKwOpqFs=; b=QHQlDcDO0MCrnIkl0tkO2s3ZeiZNqrMXW8Mkb7U2wlbnGkbcK44HSZZ9YcDpzXZT68+odq 45+3VRt5HgVZA08uvHDW4J7HaW6oKJck9XyVVxKjWUSZzxnUEFLsNgEnnqJChCU+pu+uMz lsu1S46NMIN24LTwOEGpvSqxafmWD5g= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-327-cOZKar-pO0C3scoMmziVUw-1; Tue, 26 May 2020 00:48:47 -0400 X-MC-Unique: cOZKar-pO0C3scoMmziVUw-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 0B4241005512; Tue, 26 May 2020 04:48:46 +0000 (UTC) Received: from sirius.home.kraxel.org (ovpn-113-50.ams2.redhat.com [10.36.113.50]) by smtp.corp.redhat.com (Postfix) with ESMTP id 3777F5D9E5; Tue, 26 May 2020 04:48:40 +0000 (UTC) Received: by sirius.home.kraxel.org (Postfix, from userid 1000) id 32DC81753B; Tue, 26 May 2020 06:48:39 +0200 (CEST) Date: Tue, 26 May 2020 06:48:39 +0200 From: Gerd Hoffmann To: Igor Mammedov Subject: Re: [PATCH v3 14/22] microvm: use 2G split unconditionally Message-ID: <20200526044839.bncj6iltugnzgfmy@sirius.home.kraxel.org> References: <20200520132003.9492-1-kraxel@redhat.com> <20200520132003.9492-15-kraxel@redhat.com> <20200521112921.641f12bb@redhat.com> <20200525114508.hhvyzjiqja6knz6l@sirius.home.kraxel.org> <20200525183615.5f8e67d3@redhat.com> MIME-Version: 1.0 In-Reply-To: <20200525183615.5f8e67d3@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Received-SPF: pass client-ip=207.211.31.81; envelope-from=kraxel@redhat.com; helo=us-smtp-delivery-1.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/05/26 00:48:49 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 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, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_PASS=-0.001 autolearn=_AUTOLEARN 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: Peter Maydell , Eduardo Habkost , Sergio Lopez , "Michael S. Tsirkin" , qemu-devel@nongnu.org, Shannon Zhao , qemu-arm@nongnu.org, Paolo Bonzini , Richard Henderson Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" > > Well, I think we can (should) drop max-ram-below-4g too. There is > > no reason to use that with microvm, other that shooting yourself into > > the foot (by making mmio overlap with ram). > > > > With that being gone too there isn't much logic left ... > > I wonder if we need 2G split for microvm at all? > Can we map 1 contiguous big blob from 0 GPA and overlay bios & other x86 TOLUD stuff? I think it would work, but it has some drawbacks: (1) we loose a bit of memory. (2) we loose a gigabyte page. (3) we wouldn't have guard pages (unused address space) between between ram and mmio space. take care, Gerd