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 E57D5C433EF for ; Wed, 10 Nov 2021 13:55:45 +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 9634D610FC for ; Wed, 10 Nov 2021 13:55:45 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 9634D610FC 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]:52308 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1mko4m-0006Px-Kn for qemu-devel@archiver.kernel.org; Wed, 10 Nov 2021 08:55:44 -0500 Received: from eggs.gnu.org ([209.51.188.92]:38442) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mko1G-0000Je-Gb for qemu-devel@nongnu.org; Wed, 10 Nov 2021 08:52:06 -0500 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:27215) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mko1B-0006FG-KG for qemu-devel@nongnu.org; Wed, 10 Nov 2021 08:52:06 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1636552315; 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=y2xasQ5elESghAIaOqJcB05MPj9E2/OcMNPtqeAj29Q=; b=LMmUEuiyUkgXXQqomvdi2Tv9fSoiFuKOXnWKRjv87VEDWeUe5H5qK0khKHMia9rGtlOiZB mcD9brGAM47wMCc2bkN57Eh0gd2WS74AaH4bvJtwckJmAhW7ie6kQbKDVAR4r6NML2pW6N 5zpXVIFr4L8tFuVUms+LUGesEN7GMdA= 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-417-Tk48Nr6JN66Vtgug7b-3UA-1; Wed, 10 Nov 2021 08:51:52 -0500 X-MC-Unique: Tk48Nr6JN66Vtgug7b-3UA-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id CB9311882FB1; Wed, 10 Nov 2021 13:51:51 +0000 (UTC) Received: from paraplu (unknown [10.39.195.97]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 3FCF560C0F; Wed, 10 Nov 2021 13:51:49 +0000 (UTC) Date: Wed, 10 Nov 2021 14:51:47 +0100 From: Kashyap Chamarthy To: qemu-devel@nongnu.org Subject: Re: [PATCH] cpu-models-x86.rst: Tidy up a couple of things Message-ID: References: <20211015152259.2948176-1-kchamart@redhat.com> MIME-Version: 1.0 In-Reply-To: <20211015152259.2948176-1-kchamart@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 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=216.205.24.124; envelope-from=kchamart@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -34 X-Spam_score: -3.5 X-Spam_bar: --- X-Spam_report: (-3.5 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.699, 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: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Paolo Bonzini , Richard Henderson , Daniel P =?iso-8859-1?Q?=2E_Berrang=E9?= , Eduardo Habkost Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Fri, Oct 15, 2021 at 05:22:59PM +0200, Kashyap Chamarthy wrote: > - Remove stray texinfo syntax (remnants of texinfo to rST conversion) > - Clarify the bit about long-term stable CPU models > > TODO: In a future patch, include potential examples as discussed > here[1]. > > [1] https://lists.nongnu.org/archive/html/qemu-devel/2021-10/msg03411.html > -- On versioned CPU models, aliases, and machine types Ping? I'd also appreciate if anyone can also answer the two questions I raised in the above thread[1]. > Signed-off-by: Kashyap Chamarthy > --- > Eduardo/DanPB: I'm not 100% sure if my wording got it right; please give > it a close reading to make sure I'm not making things worse. > --- > docs/system/cpu-models-x86.rst.inc | 25 +++++++++++++++++-------- > 1 file changed, 17 insertions(+), 8 deletions(-) > > diff --git a/docs/system/cpu-models-x86.rst.inc b/docs/system/cpu-models-x86.rst.inc > index 6e8be7d79b..e133753920 100644 > --- a/docs/system/cpu-models-x86.rst.inc > +++ b/docs/system/cpu-models-x86.rst.inc > @@ -25,7 +25,7 @@ Two ways to configure CPU models with QEMU / KVM > typically refer to specific generations of hardware released by > Intel and AMD. These allow the guest VMs to have a degree of > isolation from the host CPU, allowing greater flexibility in live > - migrating between hosts with differing hardware. @end table > + migrating between hosts with differing hardware. > > In both cases, it is possible to optionally add or remove individual CPU > features, to alter what is presented to the guest by default. > @@ -47,11 +47,20 @@ defined. Traditionally most operating systems and toolchains would > only target the original baseline ABI. It is expected that in > future OS and toolchains are likely to target newer ABIs. The > table that follows illustrates which ABI compatibility levels > -can be satisfied by the QEMU CPU models. Note that the table only > -lists the long term stable CPU model versions (eg Haswell-v4). > -In addition to whats listed, there are also many CPU model > -aliases which resolve to a different CPU model version, > -depending on the machine type is in use. > +can be satisfied by the QEMU CPU models. Note that the table only lists > +the long term stable CPU model versions (e.g. Haswell-v4, Haswell-v3). > +CPU models without a version tag will alias to a CPU model with a > +version tag, and the alias varies depending on the machine type. In > +addition to what is listed, there are also many CPU model aliases which > +resolve to a different CPU model version, depending on the machine type > +in use. > + > +The versioned CPU models (e.g. ``Cascadelake-Server-v4``, > +``Broadwell-v4``) are long-term stable. Further, when using a versioned > +machine type (e.g. ``pc-q35-6.0``), instead of its generic alias > +(``q35``), the CPU models that are associated with it are also long-term > +stable. This is because the CPUID features in the CPU models that are > +part of a versioned machine type do not change. > > .. _ABI compatibility levels: https://gitlab.com/x86-psABIs/x86-64-ABI/ > > @@ -185,8 +194,8 @@ features are included if using "Host passthrough" or "Host model". > guest. Instead, the host kernel uses it to populate the MDS > vulnerability file in ``sysfs``. > > - So it should only be enabled for VMs if the host reports @code{Not > - affected} in the ``/sys/devices/system/cpu/vulnerabilities/mds`` file. > + So it should only be enabled for VMs if the host reports ``Not > + affected`` in the ``/sys/devices/system/cpu/vulnerabilities/mds`` file. > > ``taa-no`` > Recommended to inform that the guest that the host is ``not`` > -- > 2.31.1 > -- /kashyap