From nobody Mon Feb 9 09:16:19 2026 Delivered-To: importer@patchew.org Received-SPF: pass (zoho.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Authentication-Results: mx.zohomail.com; spf=pass (zoho.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=fail(p=none dis=none) header.from=redhat.com ARC-Seal: i=1; a=rsa-sha256; t=1562179773; cv=none; d=zoho.com; s=zohoarc; b=jAD7DzzAzlaGOG5XiEOjr9MZLOY5ojtJtRe1JDi3sfSQGuHJLmjNU+moeuFUV/5bgpb26jVjayRRD3TQIN484ckvVIDM6eJP47zYYqjk6nNHldGn+4NfS/oFtIAS+Nqj/m0X3n/gqCfr/IonQiu8MJRD5zFMF+sPJMNySvsg5dU= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zoho.com; s=zohoarc; t=1562179773; h=Content-Type:Content-Transfer-Encoding:Date:From:In-Reply-To:List-Subscribe:List-Post:List-Id:List-Archive:List-Help:List-Unsubscribe:MIME-Version:Message-ID:References:Sender:Subject:To:ARC-Authentication-Results; bh=7SrTmbQQbldnJsvdMavIoujAtnvbzg/FaqjKfAMhy8g=; b=iu6DjhLOUppJw9TS/k72W8EdNoyNLEbhT7JCjaDSPzsHjKOv625emUeNJPVhj6bgxZ49irxWxhvDqf3oI87vzDDOtSUCAEoldyzBzvvSdowGqXoo9LO6LBCyGdayT93b0GyQiK3vvyMXd97vw8W5diZXFnYCS004LpbwlsJMMCU= ARC-Authentication-Results: i=1; mx.zoho.com; spf=pass (zoho.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=fail header.from= (p=none dis=none) header.from= Return-Path: Received: from lists.gnu.org (209.51.188.17 [209.51.188.17]) by mx.zohomail.com with SMTPS id 1562179773834671.7966077775807; Wed, 3 Jul 2019 11:49:33 -0700 (PDT) Received: from localhost ([::1]:38548 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hikJr-0001Vh-UF for importer@patchew.org; Wed, 03 Jul 2019 14:49:27 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:56932) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hijgl-0005Pu-FI for qemu-devel@nongnu.org; Wed, 03 Jul 2019 14:09:04 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hijgk-00015L-Eg for qemu-devel@nongnu.org; Wed, 03 Jul 2019 14:09:03 -0400 Received: from mx1.redhat.com ([209.132.183.28]:45880) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hijgk-00014g-9c for qemu-devel@nongnu.org; Wed, 03 Jul 2019 14:09:02 -0400 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 9475B8553A; Wed, 3 Jul 2019 18:09:01 +0000 (UTC) Received: from localhost (ovpn-116-30.gru2.redhat.com [10.97.116.30]) by smtp.corp.redhat.com (Postfix) with ESMTP id 5070E457C7; Wed, 3 Jul 2019 18:08:59 +0000 (UTC) From: Eduardo Habkost To: Peter Maydell , Paolo Bonzini , qemu-devel@nongnu.org, Marcel Apfelbaum , Richard Henderson Date: Wed, 3 Jul 2019 15:07:22 -0300 Message-Id: <20190703180726.31267-40-ehabkost@redhat.com> In-Reply-To: <20190703180726.31267-1-ehabkost@redhat.com> References: <20190703180726.31267-1-ehabkost@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.28]); Wed, 03 Jul 2019 18:09:01 +0000 (UTC) Content-Transfer-Encoding: quoted-printable X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.132.183.28 Subject: [Qemu-devel] [PULL v4 39/43] docs: Deprecate CPU model runnability guarantees 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: , Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" Content-Type: text/plain; charset="utf-8" Document that CPU model runnability guarantees won't apply to unversioned CPU models anymore. Signed-off-by: Eduardo Habkost Message-Id: <20190628002844.24894-9-ehabkost@redhat.com> Reviewed-by: Daniel P. Berrang=C3=A9 Signed-off-by: Eduardo Habkost --- qemu-deprecated.texi | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+) diff --git a/qemu-deprecated.texi b/qemu-deprecated.texi index 9cba82d5ec..18f85f70e1 100644 --- a/qemu-deprecated.texi +++ b/qemu-deprecated.texi @@ -276,3 +276,22 @@ Note that if you are exposing the export via /dev/nbd0= , it is easier to just export the entire image and then mount only /dev/nbd0p1 than it is to reinvoke @command{qemu-nbd -c /dev/nbd0} limited to just a subset of the image. + +@section Backwards compatibility + +@subsection Runnability guarantee of CPU models (since 4.1.0) + +Previous versions of QEMU never changed existing CPU models in +ways that introduced additional host software or hardware +requirements to the VM. This allowed management software to +safely change the machine type of an existing VM without +introducing new requirements ("runnability guarantee"). This +prevented CPU models from being updated to include CPU +vulnerability mitigations, leaving guests vulnerable in the +default configuration. + +The CPU model runnability guarantee won't apply anymore to +existing CPU models. Management software that needs runnability +guarantees must resolve the CPU model aliases using te +``alias-of'' field returned by the ``query-cpu-definitions'' QMP +command. --=20 2.18.0.rc1.1.g3f1ff2140