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Fri, 6 May 2022 09:20:28 +0000 (GMT) Received: from li-c6ac47cc-293c-11b2-a85c-d421c8e4747b.ibm.com.com (unknown [9.171.62.79]) by d06av25.portsmouth.uk.ibm.com (Postfix) with ESMTP; Fri, 6 May 2022 09:20:28 +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 Subject: [PATCH v9 0/3] s390x: KVM: CPU Topology Date: Fri, 6 May 2022 11:24:00 +0200 Message-Id: <20220506092403.47406-1-pmorel@linux.ibm.com> X-Mailer: git-send-email 2.27.0 MIME-Version: 1.0 X-TM-AS-GCONF: 00 X-Proofpoint-GUID: RvDBeqAdxUJi9e8CM5nI5Bk_2XxsrhYA X-Proofpoint-ORIG-GUID: tYw0nMt7WSgjZGyyOsmHyvKuim5yjyF1 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.205,Aquarius:18.0.858,Hydra:6.0.486,FMLib:17.11.64.514 definitions=2022-05-06_03,2022-05-05_01,2022-02-23_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 adultscore=0 phishscore=0 clxscore=1011 priorityscore=1501 mlxscore=0 mlxlogscore=999 bulkscore=0 spamscore=0 suspectscore=0 malwarescore=0 impostorscore=0 lowpriorityscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2202240000 definitions=main-2205060049 Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org Hi all, This new spin adds bug correction and simplification of ipte_lock to the series for the implementation of interpretation for the PTF instruction and the handling of the STSI instruction. The series provides: 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. 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 - modification of the CPU mask inside sockets In future development we will provide: - 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 will report 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. 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. To check if the topology has been modified we use a new field of the arch vCPU prev_cpu, to save the previous real CPU ID at the end of a schedule and verify on next schedule that the CPU used is in the same socket, this field is initialized to -1 on vCPU creation. Regards, Pierre Pierre Morel (3): s390x: KVM: ipte lock for SCA access should be contained in KVM s390x: KVM: guest support for topology function s390x: KVM: resetting the Topology-Change-Report Documentation/virt/kvm/api.rst | 16 ++++ arch/s390/include/asm/kvm_host.h | 12 ++- arch/s390/include/uapi/asm/kvm.h | 5 ++ arch/s390/kvm/gaccess.c | 96 +++++++++++------------ arch/s390/kvm/gaccess.h | 6 +- arch/s390/kvm/kvm-s390.c | 128 ++++++++++++++++++++++++++++++- arch/s390/kvm/kvm-s390.h | 25 ++++++ arch/s390/kvm/priv.c | 20 +++-- arch/s390/kvm/vsie.c | 3 + include/uapi/linux/kvm.h | 1 + 10 files changed, 250 insertions(+), 62 deletions(-)