From patchwork Thu Jan 26 09:39:43 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Nico Boehr X-Patchwork-Id: 13116824 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 0EDEAC61DA0 for ; Thu, 26 Jan 2023 09:40:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236339AbjAZJkF (ORCPT ); Thu, 26 Jan 2023 04:40:05 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46030 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236104AbjAZJjw (ORCPT ); Thu, 26 Jan 2023 04:39:52 -0500 Received: from mx0a-001b2d01.pphosted.com (mx0a-001b2d01.pphosted.com [148.163.156.1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 081265D100; Thu, 26 Jan 2023 01:39:50 -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 30Q8qJit004880; Thu, 26 Jan 2023 09:39:50 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=lmT3hLYBLwe7NZl0xborvQNO27FnZ34vpwVgqsvQhjI=; b=Mh92qObxNS3p+srqHhszlE33UGW4CcsGDwGk0Zrv73/042zNStau2tJNVYBruAmX7Vgg V9SiYghQsD+Ns5puHpr4ubBo6UBB5m6RlCmEcScbfyR9fAKW8jeUP9DNvXC3LfcNB/p4 5raYipnxK9EslxC+JfKXM3XDDzcUpjGXaGvwwLazBWRCCaUoaOi5gnrre4TQCeWrDbFH RXDcVTExL+BF54VPr+n4JGe44aUQAM5A4TqikY8kyQSTt9KxkafMKYVLCsyH6fWyHUl/ GeAwvTICj22wWO+wXnjezT4xGbos92q7KaHVPrxNQvZMUgtNfsGjFN1H5CEynRiVvPGN SA== Received: from ppma04ams.nl.ibm.com (63.31.33a9.ip4.static.sl-reverse.com [169.51.49.99]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 3nbhkaex00-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Thu, 26 Jan 2023 09:39:50 +0000 Received: from pps.filterd (ppma04ams.nl.ibm.com [127.0.0.1]) by ppma04ams.nl.ibm.com (8.17.1.19/8.17.1.19) with ESMTP id 30PGYaAm026764; Thu, 26 Jan 2023 09:39:48 GMT Received: from smtprelay03.fra02v.mail.ibm.com ([9.218.2.224]) by ppma04ams.nl.ibm.com (PPS) with ESMTPS id 3n87p6e7a5-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Thu, 26 Jan 2023 09:39:47 +0000 Received: from smtpav07.fra02v.mail.ibm.com (smtpav07.fra02v.mail.ibm.com [10.20.54.106]) by smtprelay03.fra02v.mail.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 30Q9diZu49873378 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 26 Jan 2023 09:39:44 GMT Received: from smtpav07.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 5E6B820040; Thu, 26 Jan 2023 09:39:44 +0000 (GMT) Received: from smtpav07.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 2DE462004E; Thu, 26 Jan 2023 09:39:44 +0000 (GMT) Received: from t35lp63.lnxne.boe (unknown [9.152.108.100]) by smtpav07.fra02v.mail.ibm.com (Postfix) with ESMTP; Thu, 26 Jan 2023 09:39:44 +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 v2 1/1] KVM: s390: disable migration mode when dirty tracking is disabled Date: Thu, 26 Jan 2023 10:39:43 +0100 Message-Id: <20230126093943.608468-2-nrb@linux.ibm.com> X-Mailer: git-send-email 2.39.1 In-Reply-To: <20230126093943.608468-1-nrb@linux.ibm.com> References: <20230126093943.608468-1-nrb@linux.ibm.com> MIME-Version: 1.0 X-TM-AS-GCONF: 00 X-Proofpoint-GUID: 6LBKm30A4qOueKCqZHED5Mm4uCKVrLk7 X-Proofpoint-ORIG-GUID: 6LBKm30A4qOueKCqZHED5Mm4uCKVrLk7 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=2023-01-26_03,2023-01-25_01,2022-06-22_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 clxscore=1015 mlxscore=0 priorityscore=1501 lowpriorityscore=0 suspectscore=0 phishscore=0 malwarescore=0 bulkscore=0 adultscore=0 spamscore=0 mlxlogscore=800 impostorscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2212070000 definitions=main-2301260086 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(). 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 --- Documentation/virt/kvm/devices/vm.rst | 4 +++ arch/s390/kvm/kvm-s390.c | 38 ++++++++++++++++++--------- 2 files changed, 29 insertions(+), 13 deletions(-) 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..d68c938f1fb8 100644 --- a/arch/s390/kvm/kvm-s390.c +++ b/arch/s390/kvm/kvm-s390.c @@ -5633,23 +5633,35 @@ 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; + /* + * Turn off migration mode when userspace disables dirty page logging. + * Migration mode expects dirty page logging being enabled to store + * its dirty bitmap. + */ + if (kvm->arch.migration_mode) { + if ((old->flags & KVM_MEM_LOG_DIRTY_PAGES) && + !(new->flags & KVM_MEM_LOG_DIRTY_PAGES)) + WARN_ONCE(kvm_s390_vm_stop_migration(kvm), "Failed to stop migration mode"); + } return 0; }