From patchwork Fri Jan 27 14:05:32 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Nico Boehr X-Patchwork-Id: 13118768 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 0CE58C54EAA for ; Fri, 27 Jan 2023 14:06:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234490AbjA0OGL (ORCPT ); Fri, 27 Jan 2023 09:06:11 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47550 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234348AbjA0OF4 (ORCPT ); Fri, 27 Jan 2023 09:05:56 -0500 Received: from mx0a-001b2d01.pphosted.com (mx0a-001b2d01.pphosted.com [148.163.156.1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1D52E841A0; Fri, 27 Jan 2023 06:05:40 -0800 (PST) Received: from pps.filterd (m0187473.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.17.1.19/8.17.1.19) with ESMTP id 30RDfufd029045; Fri, 27 Jan 2023 14:05:39 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=0YN4cczSPIVrF9abyN/hRX2sD4sWzoIeIwCngACBof8=; b=W6NYqJdTvdSGt88KNd778kmT2GJofzt+sKL9FeY5ogRrOl2eXzmHBLAwnB8rpEtWIp5f ftp9l84KKAl/1jlEGtbailC5OHzrZ0JQ/IHSVkR0U1V9eNbFEckzCwASArmpXTWI0Yf+ SqrA2dpwYqVYiWSCIo3UQN16tESEMxI9Sa+NMrRfLj1Gs3vOUDw1YlwSnyCRHiIAoSxs 2mlQT+FmPTfMCWmvxuIVH2ZPM4a0FyiNeIdCW11YdjnyQi0OUON+gcDm/P60CLge4ErE U8l321ZWyUJix0Qn3A2h18qF9eZpdvAJigEuRCMoJyCaMnKpS5C+Q+5/LYXT1KvIPiO5 jw== Received: from ppma06ams.nl.ibm.com (66.31.33a9.ip4.static.sl-reverse.com [169.51.49.102]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 3ncfqk8rn8-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Fri, 27 Jan 2023 14:05:39 +0000 Received: from pps.filterd (ppma06ams.nl.ibm.com [127.0.0.1]) by ppma06ams.nl.ibm.com (8.17.1.19/8.17.1.19) with ESMTP id 30R5jmiJ014941; Fri, 27 Jan 2023 14:05:37 GMT Received: from smtprelay04.fra02v.mail.ibm.com ([9.218.2.228]) by ppma06ams.nl.ibm.com (PPS) with ESMTPS id 3n87affm11-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Fri, 27 Jan 2023 14:05:36 +0000 Received: from smtpav04.fra02v.mail.ibm.com (smtpav04.fra02v.mail.ibm.com [10.20.54.103]) by smtprelay04.fra02v.mail.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 30RE5Xkm23724354 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Fri, 27 Jan 2023 14:05:33 GMT Received: from smtpav04.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 7DC8520043; Fri, 27 Jan 2023 14:05:33 +0000 (GMT) Received: from smtpav04.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 4E0292004F; Fri, 27 Jan 2023 14:05:33 +0000 (GMT) Received: from t35lp63.lnxne.boe (unknown [9.152.108.100]) by smtpav04.fra02v.mail.ibm.com (Postfix) with ESMTP; Fri, 27 Jan 2023 14:05:33 +0000 (GMT) From: Nico Boehr To: borntraeger@linux.ibm.com, frankja@linux.ibm.com, imbrenda@linux.ibm.com Cc: kvm@vger.kernel.org, linux-s390@vger.kernel.org Subject: [PATCH v4 1/1] KVM: s390: disable migration mode when dirty tracking is disabled Date: Fri, 27 Jan 2023 15:05:32 +0100 Message-Id: <20230127140532.230651-2-nrb@linux.ibm.com> X-Mailer: git-send-email 2.39.1 In-Reply-To: <20230127140532.230651-1-nrb@linux.ibm.com> References: <20230127140532.230651-1-nrb@linux.ibm.com> MIME-Version: 1.0 X-TM-AS-GCONF: 00 X-Proofpoint-GUID: 97fMHlDPlskxgVJi-pgVF6s05DEMi9a3 X-Proofpoint-ORIG-GUID: 97fMHlDPlskxgVJi-pgVF6s05DEMi9a3 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.219,Aquarius:18.0.930,Hydra:6.0.562,FMLib:17.11.122.1 definitions=2023-01-27_08,2023-01-27_01,2022-06-22_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 lowpriorityscore=0 bulkscore=0 suspectscore=0 adultscore=0 phishscore=0 malwarescore=0 mlxscore=0 mlxlogscore=963 spamscore=0 clxscore=1015 impostorscore=0 priorityscore=1501 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2212070000 definitions=main-2301270133 Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org Migration mode is a VM attribute which enables tracking of changes in storage attributes (PGSTE). It assumes dirty tracking is enabled on all memslots to keep a dirty bitmap of pages with changed storage attributes. When enabling migration mode, we currently check that dirty tracking is enabled for all memslots. However, userspace can disable dirty tracking without disabling migration mode. Since migration mode is pointless with dirty tracking disabled, disable migration mode whenever userspace disables dirty tracking on any slot. Also update the documentation to clarify that dirty tracking must be enabled when enabling migration mode, which is already enforced by the code in kvm_s390_vm_start_migration(). Also highlight in the documentation for KVM_S390_GET_CMMA_BITS that it can now fail with -EINVAL when dirty tracking is disabled while migration mode is on. Move all the error codes to a table to this stays readable. To disable migration mode, slots_lock should be held, which is taken in kvm_set_memory_region() and thus held in kvm_arch_prepare_memory_region(). Restructure the prepare code a bit so all the sanity checking is done before disabling migration mode. This ensures migration mode isn't disabled when some sanity check fails. Cc: stable@vger.kernel.org Fixes: 190df4a212a7 ("KVM: s390: CMMA tracking, ESSA emulation, migration mode") Signed-off-by: Nico Boehr Reviewed-by: Claudio Imbrenda Reviewed-by: Janosch Frank --- Documentation/virt/kvm/api.rst | 16 ++++++---- Documentation/virt/kvm/devices/vm.rst | 4 +++ arch/s390/kvm/kvm-s390.c | 43 +++++++++++++++++++-------- 3 files changed, 45 insertions(+), 18 deletions(-) diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst index 9807b05a1b57..2978acfcafc4 100644 --- a/Documentation/virt/kvm/api.rst +++ b/Documentation/virt/kvm/api.rst @@ -4537,11 +4537,17 @@ mask is unused. values points to the userspace buffer where the result will be stored. -This ioctl can fail with -ENOMEM if not enough memory can be allocated to -complete the task, with -ENXIO if CMMA is not enabled, with -EINVAL if -KVM_S390_CMMA_PEEK is not set but migration mode was not enabled, with --EFAULT if the userspace address is invalid or if no page table is -present for the addresses (e.g. when using hugepages). +Errors: + + ====== ============================================================= + ENOMEM not enough memory can be allocated to complete the task + ENXIO if CMMA is not enabled + EINVAL if KVM_S390_CMMA_PEEK is not set but migration mode was not enabled + EINVAL if KVM_S390_CMMA_PEEK is not set but dirty tracking has been + disabled (and thus migration mode was automatically disabled) + EFAULT if the userspace address is invalid or if no page table is + present for the addresses (e.g. when using hugepages). + ====== ============================================================= 4.108 KVM_S390_SET_CMMA_BITS ---------------------------- diff --git a/Documentation/virt/kvm/devices/vm.rst b/Documentation/virt/kvm/devices/vm.rst index 60acc39e0e93..147efec626e5 100644 --- a/Documentation/virt/kvm/devices/vm.rst +++ b/Documentation/virt/kvm/devices/vm.rst @@ -302,6 +302,10 @@ Allows userspace to start migration mode, needed for PGSTE migration. Setting this attribute when migration mode is already active will have no effects. +Dirty tracking must be enabled on all memslots, else -EINVAL is returned. When +dirty tracking is disabled on any memslot, migration mode is automatically +stopped. + :Parameters: none :Returns: -ENOMEM if there is not enough free memory to start migration mode; -EINVAL if the state of the VM is invalid (e.g. no memory defined); diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c index e4890e04b210..cb72f9a09fb3 100644 --- a/arch/s390/kvm/kvm-s390.c +++ b/arch/s390/kvm/kvm-s390.c @@ -5633,23 +5633,40 @@ int kvm_arch_prepare_memory_region(struct kvm *kvm, if (kvm_s390_pv_get_handle(kvm)) return -EINVAL; - if (change == KVM_MR_DELETE || change == KVM_MR_FLAGS_ONLY) - return 0; + if (change != KVM_MR_DELETE && change != KVM_MR_FLAGS_ONLY) { + /* + * A few sanity checks. We can have memory slots which have to be + * located/ended at a segment boundary (1MB). The memory in userland is + * ok to be fragmented into various different vmas. It is okay to mmap() + * and munmap() stuff in this slot after doing this call at any time + */ - /* A few sanity checks. We can have memory slots which have to be - located/ended at a segment boundary (1MB). The memory in userland is - ok to be fragmented into various different vmas. It is okay to mmap() - and munmap() stuff in this slot after doing this call at any time */ + if (new->userspace_addr & 0xffffful) + return -EINVAL; - if (new->userspace_addr & 0xffffful) - return -EINVAL; + size = new->npages * PAGE_SIZE; + if (size & 0xffffful) + return -EINVAL; - size = new->npages * PAGE_SIZE; - if (size & 0xffffful) - return -EINVAL; + if ((new->base_gfn * PAGE_SIZE) + size > kvm->arch.mem_limit) + return -EINVAL; + } - if ((new->base_gfn * PAGE_SIZE) + size > kvm->arch.mem_limit) - return -EINVAL; + if (!kvm->arch.migration_mode) + return 0; + + /* + * Turn off migration mode when: + * - userspace creates a new memslot with dirty logging off, + * - userspace modifies an existing memslot (MOVE or FLAGS_ONLY) and + * dirty logging is turned off. + * Migration mode expects dirty page logging being enabled to store + * its dirty bitmap. + */ + if (change != KVM_MR_DELETE && + !(new->flags & KVM_MEM_LOG_DIRTY_PAGES)) + WARN(kvm_s390_vm_stop_migration(kvm), + "Failed to stop migration mode"); return 0; }