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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 62B22C433EF for ; Fri, 15 Oct 2021 10:53:54 +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 F41E561056 for ; Fri, 15 Oct 2021 10:53:53 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org F41E561056 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=nongnu.org Received: from localhost ([::1]:55010 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1mbKqX-0003Wm-3L for qemu-devel@archiver.kernel.org; Fri, 15 Oct 2021 06:53:53 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:60352) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mbKpg-0002qx-9Z for qemu-devel@nongnu.org; Fri, 15 Oct 2021 06:53:00 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:60502) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mbKpe-0003gm-Ny for qemu-devel@nongnu.org; Fri, 15 Oct 2021 06:52:59 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1634295177; 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; bh=/Ofifev486097JSZ6YO2tEnUKPRS1O5CkTiLJVD+R6U=; b=Vd1UTT7KkCW5jr/GF9s9wvTrtV8ufMbJggUN9LyY9h/q6dyFrwO6pWCl5zoCK3Jou08iVh mWTRHAzaZs7rO44fvoJJ4o0I/ZhRA0VdORSStpTzQ8RqtTY2bTt47Tb6U/EudZrbxAEZPC RdCEJGA1xrxKbUzvVAEku2DniUdRC4s= 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-548-gKz5RLK-PS6XK0NTrgdjVg-1; Fri, 15 Oct 2021 06:52:56 -0400 X-MC-Unique: gKz5RLK-PS6XK0NTrgdjVg-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 4EDC318D6A25 for ; Fri, 15 Oct 2021 10:52:55 +0000 (UTC) Received: from paraplu (unknown [10.39.194.218]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 08CEF60583; Fri, 15 Oct 2021 10:52:53 +0000 (UTC) Date: Fri, 15 Oct 2021 12:52:50 +0200 From: Kashyap Chamarthy To: qemu-devel@nongnu.org Subject: On versioned CPU models, aliases, and machine types Message-ID: MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=kchamart@redhat.com 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=170.10.133.124; envelope-from=kchamart@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -28 X-Spam_score: -2.9 X-Spam_bar: -- X-Spam_report: (-2.9 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.049, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H2=-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: berrange@redhat.com, ehabkost@redhat.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Hi With the versioned CPU models, I see that the plain, non-versioned named model now says: "alias configured by machine type". For example: $> qemu-system-x86_64 -cpu help | grep Broadwell x86 Broadwell (alias configured by machine type) x86 Broadwell-IBRS (alias of Broadwell-v3) x86 Broadwell-noTSX (alias of Broadwell-v2) x86 Broadwell-noTSX-IBRS (alias of Broadwell-v4) x86 Broadwell-v1 Intel Core Processor (Broadwell) x86 Broadwell-v2 Intel Core Processor (Broadwell, no TSX) x86 Broadwell-v3 Intel Core Processor (Broadwell, IBRS) x86 Broadwell-v4 Intel Core Processor (Broadwell, no TSX, IBRS) Now, any QEMU binary (qemu-system-x86-6.0.0-1 in my case) supports a ton of versioned machine types. So when the plain "Broadwell" model says "alias configured by machine type", I have two questions: (1) Is there a way to figure out _which_ exact versioned CPU model will plain "Broadwell" alias to in the above case? My guess: Assuming I'm using the plain 'q35' machine type (which aliases to the latest versioned machine type), "Broadwell" will alias to "Broadwell-v4". (2) Also, it sounds like depending on the versioned machine type I configure, the CPU model alias of plain "Broadwell" might change -- is this correct? (Ideally, I'd like to document an example of each of the above in the in-tree doc, cpu-models-x86.rst.inc. It's not really obvious.) -- /kashyap