From patchwork Fri Jul 1 16:25:56 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Pierre Morel X-Patchwork-Id: 12903593 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1AE6DC433EF for ; Fri, 1 Jul 2022 16:31:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231779AbiGAQbW (ORCPT ); Fri, 1 Jul 2022 12:31:22 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54664 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231197AbiGAQbV (ORCPT ); Fri, 1 Jul 2022 12:31:21 -0400 Received: from mx0a-001b2d01.pphosted.com (mx0a-001b2d01.pphosted.com [148.163.156.1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4EC4C3135F; Fri, 1 Jul 2022 09:31:20 -0700 (PDT) Received: from pps.filterd (m0098396.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.17.1.5/8.17.1.5) with ESMTP id 261GVJOF024071; 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Fri, 1 Jul 2022 16:21:29 +0000 (GMT) Received: from li-c6ac47cc-293c-11b2-a85c-d421c8e4747b.ibm.com.com (unknown [9.171.92.56]) by b06wcsmtp001.portsmouth.uk.ibm.com (Postfix) with ESMTP; Fri, 1 Jul 2022 16:21:29 +0000 (GMT) From: Pierre Morel To: kvm@vger.kernel.org Cc: linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org, borntraeger@de.ibm.com, frankja@linux.ibm.com, cohuck@redhat.com, david@redhat.com, thuth@redhat.com, imbrenda@linux.ibm.com, hca@linux.ibm.com, gor@linux.ibm.com, pmorel@linux.ibm.com, wintera@linux.ibm.com, seiden@linux.ibm.com, nrb@linux.ibm.com, scgl@linux.ibm.com Subject: [PATCH v11 0/3] s390x: KVM: CPU Topology Date: Fri, 1 Jul 2022 18:25:56 +0200 Message-Id: <20220701162559.158313-1-pmorel@linux.ibm.com> X-Mailer: git-send-email 2.27.0 MIME-Version: 1.0 X-TM-AS-GCONF: 00 X-Proofpoint-ORIG-GUID: ujwOps1zlbTh9F_-7fqSnL2r-L9b7NZf X-Proofpoint-GUID: YH8DiWdOt9YmuVqFQis_W81u6RaUSG_m X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.205,Aquarius:18.0.883,Hydra:6.0.517,FMLib:17.11.122.1 definitions=2022-07-01_08,2022-06-28_01,2022-06-22_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 clxscore=1015 impostorscore=0 bulkscore=0 malwarescore=0 mlxlogscore=999 adultscore=0 lowpriorityscore=0 priorityscore=1501 phishscore=0 suspectscore=0 mlxscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2204290000 definitions=main-2207010065 Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org Hi all, This new spin suppress the check for real cpu migration and modify the checking of valid function code inside the interception of the STSI instruction. The series provides: 0- Modification of the ipte lock handling to use KVM instead of the vcpu as an argument because ipte lock work on SCA which is uniq per KVM structure and common to all vCPUs. 1- interception of the STSI instruction forwarding the CPU topology 2- interpretation of the PTF instruction 3- a KVM capability for the userland hypervisor to ask KVM to setup PTF interpretation. 4- KVM ioctl to get and set the MTCR bit of the SCA in order to migrate this bit during a migration. 0- Foreword The S390 CPU topology is reported using two instructions: - PTF, to get information if the CPU topology did change since last PTF instruction or a subsystem reset. - STSI, to get the topology information, consisting of the topology of the CPU inside the sockets, of the sockets inside the books etc. The PTF(2) instruction report a change if the STSI(15.1.2) instruction will report a difference with the last STSI(15.1.2) instruction*. With the SIE interpretation, the PTF(2) instruction will report a change to the guest if the host sets the SCA.MTCR bit. *The STSI(15.1.2) instruction reports: - The cores address within a socket - The polarization of the cores - The CPU type of the cores - If the cores are dedicated or not We decided to implement the CPU topology for S390 in several steps: - first we report CPU hotplug In future development we will provide: - modification of the CPU mask inside sockets - handling of shared CPUs - reporting of the CPU Type - reporting of the polarization 1- Interception of STSI To provide Topology information to the guest through the STSI instruction, we forward STSI with Function Code 15 to the userland hypervisor which will take care to provide the right information to the guest. To let the guest use both the PTF instruction to check if a topology change occurred and sthe STSI_15.x.x instruction we add a new KVM capability to enable the topology facility. 2- Interpretation of PTF with FC(2) The PTF instruction reports a topology change if there is any change with a previous STSI(15.1.2) SYSIB. Changes inside a STSI(15.1.2) SYSIB occur if CPU bits are set or clear inside the CPU Topology List Entry CPU mask field, which happens with changes in CPU polarization, dedication, CPU types and adding or removing CPUs in a socket. Considering that the KVM guests currently only supports: - horizontal polarization - type 3 (Linux) CPU And that we decide to support only: - dedicated CPUs on the host - pinned vCPUs on the guest the creation of vCPU will is the only trigger to set the MTCR bit for a guest. The reporting to the guest is done using the Multiprocessor Topology-Change-Report (MTCR) bit of the utility entry of the guest's SCA which will be cleared during the interpretation of PTF. Regards, Pierre Pierre Morel (3): KVM: s390: Cleanup ipte lock access and SIIF facility checks KVM: s390: guest support for topology function KVM: s390: resetting the Topology-Change-Report Documentation/virt/kvm/api.rst | 25 +++++++++ arch/s390/include/asm/kvm_host.h | 18 +++++- arch/s390/include/uapi/asm/kvm.h | 10 ++++ arch/s390/kvm/gaccess.c | 96 ++++++++++++++++---------------- arch/s390/kvm/gaccess.h | 6 +- arch/s390/kvm/kvm-s390.c | 89 +++++++++++++++++++++++++++++ arch/s390/kvm/priv.c | 22 +++++--- arch/s390/kvm/vsie.c | 8 +++ include/uapi/linux/kvm.h | 1 + 9 files changed, 214 insertions(+), 61 deletions(-)