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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id CDAF4C433F5 for ; Fri, 7 Oct 2022 13:44:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229609AbiJGNo6 (ORCPT ); Fri, 7 Oct 2022 09:44:58 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54298 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229628AbiJGNoy (ORCPT ); Fri, 7 Oct 2022 09:44:54 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id F26F31A39A for ; Fri, 7 Oct 2022 06:44:50 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1665150289; 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=AhC8RFmeUSKDRVaJH+ZIMuyo4QEyhGl15FM/C+OzzZK7AsFHYWbgRYeVsoU/L+BZFMYCp0 wPqbSdIezTUtEkaQkLgMh6KPm6isUdGYdV+4+DCwyE24C+DefCjueJGFPIZyJHunp2P2/t Qdmxf6ZJXnXLhpZ0eyxWT08d+Ao8FP4= Received: from mail-wr1-f70.google.com (mail-wr1-f70.google.com [209.85.221.70]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_128_GCM_SHA256) id us-mta-588-UcEvv5ZiOEy9-uAhawvB5A-1; Fri, 07 Oct 2022 09:44:48 -0400 X-MC-Unique: UcEvv5ZiOEy9-uAhawvB5A-1 Received: by mail-wr1-f70.google.com with SMTP id h4-20020adfa4c4000000b0022ec3966c3aso486800wrb.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=ZbTohiCSjiO5EBA8hd53P92gpGwOL4Ox+G8SmtzmjpEHAq2CnrWt20CRoEm4mVCdrV gEO7zVISx4RE9HBTk7AcwwR4du82NuL1ReCCKLle+icvz34cfgq1AV+3snzvUCB54zPy 4dpfx4ns458If45GhTWz1tM6ZRnb2ru2IQn2F3iSL6ZqNXbkiiifeOHZ2EenWMocw3WG wMyI1RebCdvu0SI9y/yhM5+ccmQKr1Sjw6U8tCXrfxeIOtvSnwlFPe7drVijJCYROcwX c2FnCLwJS4q/zThoo+JVaaNhme+aLGDB+oONwWpNSfBwQw7TveXjbPH5K/xB29JE8yGA 9KCQ== X-Gm-Message-State: ACrzQf0nMCXDgg1BmVBVU+LSSRrFYB1pV2z96I0bFtW6EL5RmF4x+D++ 05padk+r4DdHKj7tDKyJdenDUXpjsyEPWcLS1FAxmgfqELlNPaAdi5aecUc20K93/1T2XDWVwm4 bK7LufhzaKc5q X-Received: by 2002:a5d:6446:0:b0:22c:df37:4d76 with SMTP id d6-20020a5d6446000000b0022cdf374d76mr3335337wrw.247.1665150287589; 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> Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org 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