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 X-Spam-Level: X-Spam-Status: No, score=-0.9 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 42ADFC2D0DB for ; Wed, 22 Jan 2020 09:36:48 +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 0E6C92467B for ; Wed, 22 Jan 2020 09:36:47 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="PpZcCIG4" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 0E6C92467B Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:39084 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iuCRL-00087c-6C for qemu-devel@archiver.kernel.org; Wed, 22 Jan 2020 04:36:47 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:52735) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iuCQf-0007hp-DM for qemu-devel@nongnu.org; Wed, 22 Jan 2020 04:36:06 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1iuCQd-0003qA-HT for qemu-devel@nongnu.org; Wed, 22 Jan 2020 04:36:04 -0500 Received: from us-smtp-2.mimecast.com ([205.139.110.61]:22385 helo=us-smtp-delivery-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1iuCQd-0003pL-DS for qemu-devel@nongnu.org; Wed, 22 Jan 2020 04:36:03 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1579685762; 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: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=8O25dfzJf9MlYrE+F4+xVcQXBQ2bStZjlLQIjNJejM8=; b=PpZcCIG4evVlYWBmzyi3p9uFruroD+WxlX4E7LK257Q23OwqLS47psV8ZPQAgC/7PZdGlu jCq8+L4a8zyGRfjwkTeU59fxD6DFM7iMCbCryaWV+2G90d/C8JN+PTGop7CKaFvpBA3u0T dXEZM3jWGEJ0MCZk+Ge1i4nnCxx9jIA= 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-268-aAmINmDuOkO1HglFpaW_GQ-1; Wed, 22 Jan 2020 04:36:00 -0500 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 C572D107ACC4 for ; Wed, 22 Jan 2020 09:35:59 +0000 (UTC) Received: from paraplu.localdomain (unknown [10.36.118.12]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 9226760BE0; Wed, 22 Jan 2020 09:35:59 +0000 (UTC) Received: by paraplu.localdomain (Postfix, from userid 1001) id 8D4023E0489; Wed, 22 Jan 2020 10:35:57 +0100 (CET) Date: Wed, 22 Jan 2020 10:35:57 +0100 From: Kashyap Chamarthy To: qemu-devel@nongnu.org Subject: Re: [PATCH v2] qemu-cpu-models: Document -noTSX, mds-no, taa-no, and tsx-ctrl Message-ID: <20200122093557.GC24159@paraplu> References: <20200121184940.26520-1-kchamart@redhat.com> MIME-Version: 1.0 In-Reply-To: <20200121184940.26520-1-kchamart@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 X-MC-Unique: aAmINmDuOkO1HglFpaW_GQ-1 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: quoted-printable Content-Disposition: inline X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 205.139.110.61 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: pbonzini@redhat.com, berrange@redhat.com, ehabkost@redhat.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Tue, Jan 21, 2020 at 07:49:39PM +0100, Kashyap Chamarthy wrote: [...] > +@item @code{taa-no} > + > +Recommended to inform that the guest that the host is @i{not} vulnerable > +to CVE-2019-11135, TSX Asyncrnous Abort (TAA). > + > +This too is an MSR feature, so it does not show up in the Linux > +@code{/proc/cpuinfo} in the host or guest. > + > +It should only be enabled for VMs if the host reports @code{Not > +affected} in the > +@code{/sys/devices/system/cpu/vulnerabilities/tsx_async_abort} file. > + > +@item @code{tsx-ctrl} > + > +Recommended to inform the guest to @i{disable} the Intel TSX > +(Transactional Synchronization Extensions) feature. Expose this to the > +guest OS if and only if: (a) the host has TSX enabled; and (b) the guest > +has @code{rtm} CPU flag enabled. > + > +By disabling TSX, KVM-based guests can avoid paying the price of > +mitigting TSX-based attacks. > + > +Note that too is an MSR feature,=20 "Note that too" --> "Note that this too" (Will wait for other feedback. If there no need to respin, maybe the pull-req submitter can do the touch-up.) > so it does not show up in the Linux > +@code{/proc/cpuinfo} in the host or guest. > + > @end table > =20 > - > @node preferred_cpu_models_amd_x86 > @subsubsection Preferred CPU models for AMD x86 hosts > =20 > --=20 > 2.21.0 >=20 >=20 --=20 /kashyap