From patchwork Thu Dec 8 09:44:32 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Pierre Morel X-Patchwork-Id: 13068182 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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id B5263C3A5A7 for ; Thu, 8 Dec 2022 09:47:42 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1p3DT4-0002nr-2b; Thu, 08 Dec 2022 04:45:26 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1p3DSY-0002hz-NQ; Thu, 08 Dec 2022 04:44:54 -0500 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1p3DSW-00045z-HP; Thu, 08 Dec 2022 04:44:54 -0500 Received: from pps.filterd (m0098417.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.17.1.19/8.17.1.19) with ESMTP id 2B89HSjU013456; Thu, 8 Dec 2022 09:44:43 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ibm.com; h=from : to : cc : subject : date : message-id : in-reply-to : references : mime-version : content-transfer-encoding; s=pp1; bh=cG8TO8J0JhjMLHeFR+gvjjd0ZIzzXmKYU9QQQjVs628=; b=ow8MZrsfQF1gZQkCVa+NhvofbIZ7XkbnTyxsNNd89YANCf4oKiiQ8JLkhrV4EPXXnA0d 8DsI6aqdvan8nrz3LiRAy+XZVid6CrECOKHvtLuHJ91qwiPj0fg6PEvwI27eZlVgmsjH 6MZtdCm+qVGvFvX/pj7/wUMX95NFFGTXHKFZCzdn4PfHqQyf+EegQgVcDA2cEGmQZ2DR vhXr98lygQhPCn7p4iw7w5DxmxFnYyg7Vu0lHteAs8uhiGA4lAZPN7Cmnj3x6yxZVM1A HWLbKb+9GXg55g3twe0mATa7oDlxuga3nwMYDVuIuuHT4455msB0+xxQlSU7DwUWKlHj wA== Received: from pps.reinject (localhost [127.0.0.1]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 3mbd5cgmex-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Thu, 08 Dec 2022 09:44:43 +0000 Received: from m0098417.ppops.net (m0098417.ppops.net [127.0.0.1]) by pps.reinject (8.17.1.5/8.17.1.5) with ESMTP id 2B89h5we027592; Thu, 8 Dec 2022 09:44:42 GMT Received: from ppma02fra.de.ibm.com (47.49.7a9f.ip4.static.sl-reverse.com [159.122.73.71]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 3mbd5cgme9-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Thu, 08 Dec 2022 09:44:42 +0000 Received: from pps.filterd (ppma02fra.de.ibm.com [127.0.0.1]) by ppma02fra.de.ibm.com (8.17.1.19/8.17.1.19) with ESMTP id 2B7HHaVa002553; Thu, 8 Dec 2022 09:44:40 GMT Received: from smtprelay01.fra02v.mail.ibm.com ([9.218.2.227]) by ppma02fra.de.ibm.com (PPS) with ESMTPS id 3m9mb234ca-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Thu, 08 Dec 2022 09:44:40 +0000 Received: from smtpav01.fra02v.mail.ibm.com (smtpav01.fra02v.mail.ibm.com [10.20.54.100]) by smtprelay01.fra02v.mail.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 2B89iahT40239386 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 8 Dec 2022 09:44:37 GMT Received: from smtpav01.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id B0B9C20043; Thu, 8 Dec 2022 09:44:36 +0000 (GMT) Received: from smtpav01.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 4B7872004D; Thu, 8 Dec 2022 09:44:36 +0000 (GMT) Received: from li-c6ac47cc-293c-11b2-a85c-d421c8e4747b.ibm.com (unknown [9.152.222.245]) by smtpav01.fra02v.mail.ibm.com (Postfix) with ESMTP; Thu, 8 Dec 2022 09:44:36 +0000 (GMT) From: Pierre Morel To: qemu-s390x@nongnu.org Cc: qemu-devel@nongnu.org, borntraeger@de.ibm.com, pasic@linux.ibm.com, richard.henderson@linaro.org, david@redhat.com, thuth@redhat.com, cohuck@redhat.com, mst@redhat.com, pbonzini@redhat.com, kvm@vger.kernel.org, ehabkost@redhat.com, marcel.apfelbaum@gmail.com, eblake@redhat.com, armbru@redhat.com, seiden@linux.ibm.com, nrb@linux.ibm.com, scgl@linux.ibm.com, frankja@linux.ibm.com, berrange@redhat.com, clg@kaod.org Subject: [PATCH v13 7/7] docs/s390x: document s390x cpu topology Date: Thu, 8 Dec 2022 10:44:32 +0100 Message-Id: <20221208094432.9732-8-pmorel@linux.ibm.com> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20221208094432.9732-1-pmorel@linux.ibm.com> References: <20221208094432.9732-1-pmorel@linux.ibm.com> MIME-Version: 1.0 X-TM-AS-GCONF: 00 X-Proofpoint-GUID: LYdLbaQtXdsdPJ9IKDCUqK5lywi98jhi X-Proofpoint-ORIG-GUID: Xec_YaXbKLzt6rfLXJMBDnEdpcgvdywQ X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.205,Aquarius:18.0.923,Hydra:6.0.545,FMLib:17.11.122.1 definitions=2022-12-08_04,2022-12-07_01,2022-06-22_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 clxscore=1015 mlxlogscore=999 malwarescore=0 spamscore=0 mlxscore=0 lowpriorityscore=0 priorityscore=1501 bulkscore=0 impostorscore=0 phishscore=0 adultscore=0 suspectscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2210170000 definitions=main-2212080077 Received-SPF: pass client-ip=148.163.158.5; envelope-from=pmorel@linux.ibm.com; helo=mx0b-001b2d01.pphosted.com X-Spam_score_int: -19 X-Spam_score: -2.0 X-Spam_bar: -- X-Spam_report: (-2.0 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_EF=-0.1, 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: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Add some basic examples for the definition of cpu topology in s390x. Signed-off-by: Pierre Morel --- docs/system/s390x/cpu-topology.rst | 87 ++++++++++++++++++++++++++++++ docs/system/target-s390x.rst | 1 + 2 files changed, 88 insertions(+) create mode 100644 docs/system/s390x/cpu-topology.rst diff --git a/docs/system/s390x/cpu-topology.rst b/docs/system/s390x/cpu-topology.rst new file mode 100644 index 0000000000..12f974cc54 --- /dev/null +++ b/docs/system/s390x/cpu-topology.rst @@ -0,0 +1,87 @@ +CPU Topology on s390x +===================== + +CPU Topology on S390x provides up to 5 levels of topology containers: +nodes, drawers, books, sockets and CPUs. +While the higher level containers, Containers Topology List Entries, +(Containers TLE) define a tree hierarchy, the lowest level of topology +definition, the CPU Topology List Entry (CPU TLE), provides the placement +of the CPUs inside the parent container. + +Currently QEMU CPU topology uses a single level of container: the sockets. + +For backward compatibility, threads can be declared on the ``-smp`` command +line. They will be seen as CPUs by the guest as long as multithreading +is not really supported by QEMU for S390. + +Prerequisites +------------- + +To use CPU Topology a Linux QEMU/KVM machine providing the CPU Topology facility +(STFLE bit 11) is required. + +However, since this facility has been enabled by default in an early version +of QEMU, we use a capability, ``KVM_CAP_S390_CPU_TOPOLOGY``, to notify KVM +QEMU use of the CPU Topology. + +Enabling CPU topology +--------------------- + +Currently, CPU topology is only enabled in the host model. + +Enabling CPU topology in a CPU model is done by setting the CPU flag +``ctop`` to ``on`` like in: + +.. code-block:: bash + + -cpu gen16b,ctop=on + +Having the topology disabled by default allows migration between +old and new QEMU without adding new flags. + +Indicating the CPU topology to the Virtual Machine +-------------------------------------------------- + +The CPU Topology, can be specified on the QEMU command line +with the ``-smp`` or the ``-device`` QEMU command arguments. + +In the following machine we define 8 sockets with 4 cores each. +Note that S390 QEMU machines do not implement multithreading. + +.. code-block:: bash + + $ qemu-system-s390x -m 2G \ + -cpu gen16b,ctop=on \ + -smp cpus=5,sockets=8,cores=4,maxcpus=32 \ + -device host-s390x-cpu,core-id=14 \ + +New CPUs can be plugged using the device_add hmp command like in: + +.. code-block:: bash + + (qemu) device_add host-s390x-cpu,core-id=9 + +The core-id defines the placement of the core in the topology by +starting with core 0 in socket 0 up to maxcpus. + +In the example above: + +* There are 5 CPUs provided to the guest with the ``-smp`` command line + They will take the core-ids 0,1,2,3,4 + As we have 4 cores in a socket, we have 4 CPUs provided + to the guest in socket 0, with core-ids 0,1,2,3. + The last cpu, with core-id 4, will be on socket 1. + +* the core with ID 14 provided by the ``-device`` command line will + be placed in socket 3, with core-id 14 + +* the core with ID 9 provided by the ``device_add`` qmp command will + be placed in socket 2, with core-id 9 + +Note that the core ID is machine wide and the CPU TLE masks provided +by the STSI instruction will be writen in a big endian mask: + +* in socket 0: 0xf0000000 (core id 0,1,2,3) +* in socket 1: 0x08000000 (core id 4) +* in socket 2: 0x00400000 (core id 9) +* in socket 3: 0x00020000 (core id 14) diff --git a/docs/system/target-s390x.rst b/docs/system/target-s390x.rst index c636f64113..ff0ffe04f3 100644 --- a/docs/system/target-s390x.rst +++ b/docs/system/target-s390x.rst @@ -33,3 +33,4 @@ Architectural features .. toctree:: s390x/bootdevices s390x/protvirt + s390x/cpu-topology