From patchwork Wed Mar 30 12:25:47 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Claudio Imbrenda X-Patchwork-Id: 12795768 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 103ABC4332F for ; Wed, 30 Mar 2022 12:38:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1345239AbiC3Mhq (ORCPT ); Wed, 30 Mar 2022 08:37:46 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48316 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1343702AbiC3Mh2 (ORCPT ); Wed, 30 Mar 2022 08:37:28 -0400 Received: from mx0a-001b2d01.pphosted.com (mx0a-001b2d01.pphosted.com [148.163.156.1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 78CB990241; Wed, 30 Mar 2022 05:26:17 -0700 (PDT) Received: from pps.filterd (m0098394.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.1.2/8.16.1.2) with SMTP id 22UCMqS9032682; Wed, 30 Mar 2022 12:26:17 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ibm.com; h=from : to : cc : subject : date : message-id : mime-version : content-transfer-encoding; s=pp1; bh=ms5q9G6O4aLNlV2ELvVMNiWUog1bQB+KH53UhpHGfX4=; b=A37Nx7nl52vaDBl4F5YqLufX6HUFD9UAnkfUKq+lL/XiVUUDHmun+rGaxLbDcnSynk1X XrftLjxd3G7kqDCpRiCcNGZY9eMq/tLBoKmH7DxXCH1NZuB6qJMVAGebU1K8FY6ZnYv0 5tekTjF1o4lSvmE3nFvSP9qcZ8MkHGrsxsSNJCN+y9cJXFpeLh1Nk6O/IY6iLp4NJUSc XCSiDlQ5iEX3wHd5o0tPa8knzTmB5aGmsXlQVQVytnwE7iPfIcC+qYxcH6W/KsGaplr9 4yLX3y2oFemEocSZo1QdCypSRHDrWHqtsiEkpyiqlDqB+iZ/XIt0AKkPF4wNqWgWWGE4 rQ== Received: from pps.reinject (localhost [127.0.0.1]) by mx0a-001b2d01.pphosted.com with ESMTP id 3f3yqmntfw-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 30 Mar 2022 12:26:17 +0000 Received: from m0098394.ppops.net (m0098394.ppops.net [127.0.0.1]) by pps.reinject (8.16.0.43/8.16.0.43) with SMTP id 22UCPEPZ026048; Wed, 30 Mar 2022 12:26:16 GMT Received: from ppma01fra.de.ibm.com (46.49.7a9f.ip4.static.sl-reverse.com [159.122.73.70]) by mx0a-001b2d01.pphosted.com with ESMTP id 3f3yqmntfd-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 30 Mar 2022 12:26:16 +0000 Received: from pps.filterd (ppma01fra.de.ibm.com [127.0.0.1]) by ppma01fra.de.ibm.com (8.16.1.2/8.16.1.2) with SMTP id 22UCN0NJ012968; Wed, 30 Mar 2022 12:26:14 GMT Received: from b06cxnps4075.portsmouth.uk.ibm.com (d06relay12.portsmouth.uk.ibm.com [9.149.109.197]) by ppma01fra.de.ibm.com with ESMTP id 3f1tf8q9dm-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 30 Mar 2022 12:26:14 +0000 Received: from d06av25.portsmouth.uk.ibm.com (d06av25.portsmouth.uk.ibm.com [9.149.105.61]) by b06cxnps4075.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 22UCQARr43909550 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 30 Mar 2022 12:26:10 GMT Received: from d06av25.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id D663F11C052; Wed, 30 Mar 2022 12:26:10 +0000 (GMT) Received: from d06av25.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 5105911C04A; Wed, 30 Mar 2022 12:26:10 +0000 (GMT) Received: from localhost.localdomain (unknown [9.145.13.95]) by d06av25.portsmouth.uk.ibm.com (Postfix) with ESMTP; Wed, 30 Mar 2022 12:26:10 +0000 (GMT) From: Claudio Imbrenda To: kvm@vger.kernel.org Cc: borntraeger@de.ibm.com, frankja@linux.ibm.com, thuth@redhat.com, pasic@linux.ibm.com, david@redhat.com, linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org, scgl@linux.ibm.com, mimu@linux.ibm.com, nrb@linux.ibm.com Subject: [PATCH v9 00/18] KVM: s390: pv: implement lazy destroy for reboot Date: Wed, 30 Mar 2022 14:25:47 +0200 Message-Id: <20220330122605.247613-1-imbrenda@linux.ibm.com> X-Mailer: git-send-email 2.34.1 MIME-Version: 1.0 X-TM-AS-GCONF: 00 X-Proofpoint-GUID: nMWmvcINN-9hOIPYjWYXAY6412dHJ3o9 X-Proofpoint-ORIG-GUID: CnK3NP5QsSPaLP80x4elO1zWksh095Zk X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.205,Aquarius:18.0.850,Hydra:6.0.425,FMLib:17.11.64.514 definitions=2022-03-30_03,2022-03-30_01,2022-02-23_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 impostorscore=0 mlxscore=0 bulkscore=0 spamscore=0 phishscore=0 malwarescore=0 suspectscore=0 adultscore=0 priorityscore=1501 mlxlogscore=999 lowpriorityscore=0 clxscore=1015 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2202240000 definitions=main-2203300062 Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org Previously, when a protected VM was rebooted or when it was shut down, its memory was made unprotected, and then the protected VM itself was destroyed. Looping over the whole address space can take some time, considering the overhead of the various Ultravisor Calls (UVCs). This means that a reboot or a shutdown would take a potentially long amount of time, depending on the amount of used memory. This patchseries implements a deferred destroy mechanism for protected guests. When a protected guest is destroyed, its memory can be cleared in background, allowing the guest to restart or terminate significantly faster than before. There are 2 possibilities when a protected VM is torn down: * it still has an address space associated (reboot case) * it does not have an address space anymore (shutdown case) For the reboot case, two new commands are available for the KVM_S390_PV_COMMAND: KVM_PV_ASYNC_DISABLE_PREPARE: prepares the current protected VM for asynchronous teardown. The current VM will then continue immediately as non-protected. If a protected VM had already been set aside without starting the teardown process, this call will fail. In this case the userspace process should issue a normal KVM_PV_DISABLE KVM_PV_ASYNC_DISABLE: tears down the protected VM previously set aside for asychronous teardown. This PV command should ideally be issued by userspace from a separate thread. If a fatal signal is received (or the process terminates naturally), the command will terminate immediately without completing. The idea is that userspace should first issue the KVM_PV_ASYNC_DISABLE_PREPARE command, and in case of success, create a new thread and issue KVM_PV_ASYNC_DISABLE from there. This also allows for proper accounting of the CPU time needed for the asynchronous teardown. This means that the same address space can have memory belonging to more than one protected guest, although only one will be running, the others will in fact not even have any CPUs. The shutdown case should be dealt with in userspace (e.g. using clone(CLONE_VM)). A module parameter is also provided to disable the new functionality, which is otherwise enabled by default. This should not be an issue since the new functionality is opt-in anyway. This is mainly thought to aid debugging. v8->v9 * rebased * added dependency on MMU_NOTIFIER for KVM in arch/s390/kvm/Kconfig * add support for the Destroy Secure Configuration Fast UVC * minor fixes v7->v8 * switched patches 8 and 9 * improved comments, documentation and patch descriptions * remove mm notifier when the struct kvm is torn down * removed useless locks in the mm notifier * use _ASCE_ORIGIN instead of PAGE_MASK for ASCEs * cleanup of some compiler warnings * remove some harmless but useless duplicate code * the last parameter of __s390_uv_destroy_range is now bool * rename the KVM capability to KVM_CAP_S390_PROTECTED_ASYNC_DISABLE v6->v7 * moved INIT_LIST_HEAD inside spinlock in patch 1 * improved commit messages in patch 2 * added missing locks in patch 3 * added and expanded some comments in patch 11 * rebased v5->v6 * completely reworked the series * removed kernel thread for asynchronous teardown * added new commands to KVM_S390_PV_COMMAND ioctl v4->v5 * fixed and improved some patch descriptions * added some comments to better explain what's going on * use vma_lookup instead of find_vma * rename is_protected to protected_count since now it's used as a counter v3->v4 * added patch 2 * split patch 3 * removed the shutdown part -- will be a separate patchseries * moved the patch introducing the module parameter v2->v3 * added definitions for CC return codes for the UVC instruction * improved make_secure_pte: - renamed rc to cc - added comments to explain why returning -EAGAIN is ok * fixed kvm_s390_pv_replace_asce and kvm_s390_pv_remove_old_asce: - renamed - added locking - moved to gmap.c * do proper error management in do_secure_storage_access instead of trying again hoping to get a different exception * fix outdated patch descriptions v1->v2 * rebased on a more recent kernel * improved/expanded some patch descriptions * improves/expanded some comments * added patch 1, which prevents stall notification when the system is under heavy load. * rename some members of struct deferred_priv to improve readability * avoid an use-after-free bug of the struct mm in case of shutdown * add missing return when lazy destroy is disabled * add support for OOM notifier Claudio Imbrenda (18): KVM: s390: pv: leak the topmost page table when destroy fails KVM: s390: pv: handle secure storage violations for protected guests KVM: s390: pv: handle secure storage exceptions for normal guests KVM: s390: pv: refactor s390_reset_acc KVM: s390: pv: usage counter instead of flag KVM: s390: pv: add export before import KVM: s390: pv: module parameter to fence lazy destroy KVM: s390: pv: clear the state without memset KVM: s390: pv: Add kvm_s390_cpus_from_pv to kvm-s390.h and add documentation KVM: s390: pv: add mmu_notifier s390/mm: KVM: pv: when tearing down, try to destroy protected pages KVM: s390: pv: refactoring of kvm_s390_pv_deinit_vm KVM: s390: pv: cleanup leftover protected VMs if needed KVM: s390: pv: asynchronous destroy for reboot KVM: s390: pv: api documentation for asynchronous destroy KVM: s390: pv: add KVM_CAP_S390_PROTECTED_ASYNC_DISABLE KVM: s390: pv: avoid export before import if possible KVM: s390: pv: support for Destroy fast UVC Documentation/virt/kvm/api.rst | 25 ++- arch/s390/include/asm/gmap.h | 39 +++- arch/s390/include/asm/kvm_host.h | 4 + arch/s390/include/asm/mmu.h | 2 +- arch/s390/include/asm/mmu_context.h | 2 +- arch/s390/include/asm/pgtable.h | 20 +- arch/s390/include/asm/uv.h | 11 ++ arch/s390/kernel/uv.c | 64 ++++++ arch/s390/kvm/Kconfig | 1 + arch/s390/kvm/kvm-s390.c | 64 +++++- arch/s390/kvm/kvm-s390.h | 3 + arch/s390/kvm/pv.c | 297 +++++++++++++++++++++++++++- arch/s390/mm/fault.c | 23 ++- arch/s390/mm/gmap.c | 158 ++++++++++++--- include/uapi/linux/kvm.h | 3 + 15 files changed, 670 insertions(+), 46 deletions(-)