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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id E5413C433F5 for ; Fri, 7 Oct 2022 15:24:02 +0000 (UTC) Received: from localhost ([::1]:58332 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1ogpCk-0003VG-1t for qemu-devel@archiver.kernel.org; Fri, 07 Oct 2022 11:24:02 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:42098) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1ognep-0000R6-1d for qemu-devel@nongnu.org; Fri, 07 Oct 2022 09:44:55 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]:56234) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1ognel-0006gv-Dv for qemu-devel@nongnu.org; Fri, 07 Oct 2022 09:44:52 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1665150290; 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=4GMPD8oqBS4LOqgQsiw5vIOtVWDGebMorjW0XBAzndo=; b=Ml859RmzaOUiaqbEwLCZnqjNxxiqIGGeobHjuM+gO1NSqj0+6OXOnWiW5anHNsZaKsvM6o NuTbJK+jRK6bbODlr4T9L8XPyUozws/AzUX/udCMJ3+OpCecaJGhFIQTLmWpMrHTbq5/77 jOuxDXj4LXOe2muHx0G35xYue6mhpLA= Received: from mail-wm1-f69.google.com (mail-wm1-f69.google.com [209.85.128.69]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_128_GCM_SHA256) id us-mta-669-CXPE5s3iNNinBElHPYKPXA-1; Fri, 07 Oct 2022 09:44:48 -0400 X-MC-Unique: CXPE5s3iNNinBElHPYKPXA-1 Received: by mail-wm1-f69.google.com with SMTP id f26-20020a7bcc1a000000b003c03db14864so1409410wmh.6 for ; Fri, 07 Oct 2022 06:44:48 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=4GMPD8oqBS4LOqgQsiw5vIOtVWDGebMorjW0XBAzndo=; b=NlU0DGipLRc04c47ppedJpE/ym1oLyJwNoa+r99P9orfb9D9xRip0+8NjWByXXuGNy VQLYrNuFuqYCIc0ZWOi29/3EC+t5Sa3Alicot02vb+wli5K3A5Tk1Ib9AciMG7oULJv5 Bal1cDyhuKkaZmqFQifAFcclAUoqUwZQSTsN0AVqNo8uXMEaolYUk+HdizDixWj8pwna 2qSi/mlL+d57S8n1vqerCUeE2T+TjnuXATtMNfmUfUy1osUB5YyYCbZSITA86Cb32/nd oP4IzLEtwofQHzBt+0cQUKzGugfDS33zDN5goIDYKK/DAh96Bl6hdF9kPBADS1mppOS3 mVyA== X-Gm-Message-State: ACrzQf2xZMfXvqxQuKiM93B8GuqWDhvLVqty9TWOXxnldQEg08ppCA93 Zk6Aq0eR2vBCHFO5+Wfs2VcXiGqKVRXYltLfgt91ftkFSmZVvhpLu2Oxa4NqGJ2y2VuRsMdvF6q t8XOlVhGTzezLGyI= X-Received: by 2002:a5d:6446:0:b0:22c:df37:4d76 with SMTP id d6-20020a5d6446000000b0022cdf374d76mr3335341wrw.247.1665150287591; Fri, 07 Oct 2022 06:44:47 -0700 (PDT) X-Google-Smtp-Source: AMsMyM5JEpMmXo+TF3bHZD/1Xp0gu8UIKxaTqIvgouvJOohRPzIsn3Cy9fqHwCUVF1xdprW/WzoW2g== X-Received: by 2002:a5d:6446:0:b0:22c:df37:4d76 with SMTP id d6-20020a5d6446000000b0022cdf374d76mr3335318wrw.247.1665150287338; Fri, 07 Oct 2022 06:44:47 -0700 (PDT) Received: from redhat.com ([2.55.183.131]) by smtp.gmail.com with ESMTPSA id o11-20020a05600c510b00b003a319b67f64sm18723614wms.0.2022.10.07.06.44.44 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 07 Oct 2022 06:44:46 -0700 (PDT) Date: Fri, 7 Oct 2022 09:44:42 -0400 From: "Michael S. Tsirkin" To: Gerd Hoffmann Cc: Paolo Bonzini , Daniel =?iso-8859-1?Q?P=2E_Berrang=E9?= , qemu-devel , Sergio Lopez , Eduardo Habkost , Marcel Apfelbaum , Richard Henderson , kvm , Marcelo Tosatti Subject: Re: [PATCH v4] x86: add etc/phys-bits fw_cfg file Message-ID: <20221007094427-mutt-send-email-mst@kernel.org> References: <20220922101454.1069462-1-kraxel@redhat.com> <20220922122058.vesh352623uaon6e@sirius.home.kraxel.org> <20220922203345.3r7jteg7l75vcysv@sirius.home.kraxel.org> <20220923062312.sibqhfhfznnc22km@sirius.home.kraxel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220923062312.sibqhfhfznnc22km@sirius.home.kraxel.org> Received-SPF: pass client-ip=170.10.129.124; envelope-from=mst@redhat.com; helo=us-smtp-delivery-124.mimecast.com 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, 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: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Fri, Sep 23, 2022 at 08:23:12AM +0200, Gerd Hoffmann wrote: > Hi, > > > > Given newer processors have more than 40 and for older ones we know > > > the possible values for the two relevant x86 vendors we could do > > > something along the lines of: > > > > > > phys-bits >= 41 -> valid > > > phys-bits == 40 + AuthenticAMD -> valid > > > phys-bits == 36,39 + GenuineIntel -> valid > > > everything else -> invalid > > > > > > Does that look sensible to you? > > > > > > > Yes, it does! Is phys-bits == 36 the same as invalid? > > 'invalid' would continue to use the current guesswork codepath for > phys-bits. Which will end up with phys-bits = 36 for smaller VMs, but > it can go beyond that in VMs with alot (32G or more) of memory. That > logic assumes that physical machines with enough RAM for 32G+ guests > have a physical address space > 64G. > > 'phys-bits = 36' would be a hard limit. > > So, it's not exactly the same but small VMs wouldn't see a difference. > > take care, > Gerd I dropped the patch for now. -- MST