From patchwork Thu Jul 21 16:12:55 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Claudio Imbrenda X-Patchwork-Id: 12925570 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 169C4CCA489 for ; Thu, 21 Jul 2022 16:14:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233794AbiGUQOL (ORCPT ); Thu, 21 Jul 2022 12:14:11 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42644 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233610AbiGUQNv (ORCPT ); Thu, 21 Jul 2022 12:13:51 -0400 Received: from mx0a-001b2d01.pphosted.com (mx0a-001b2d01.pphosted.com [148.163.156.1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6717D88F24; Thu, 21 Jul 2022 09:13:41 -0700 (PDT) Received: from pps.filterd (m0187473.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.17.1.5/8.17.1.5) with ESMTP id 26LFmcYr020195; 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Thu, 21 Jul 2022 16:13:25 +0000 (GMT) Received: from p-imbrenda.ibmuc.com (unknown [9.145.4.232]) by b06wcsmtp001.portsmouth.uk.ibm.com (Postfix) with ESMTP; Thu, 21 Jul 2022 16:13:25 +0000 (GMT) From: Claudio Imbrenda To: pbonzini@redhat.com Cc: kvm@vger.kernel.org, linux-s390@vger.kernel.org, frankja@linux.ibm.com, borntraeger@linux.ibm.com, hca@linux.ibm.com, gor@linux.ibm.com, agordeev@linux.ibm.com, thuth@redhat.com, david@redhat.com, Nico Boehr Subject: [GIT PULL 35/42] KVM: s390: pv: add mmu_notifier Date: Thu, 21 Jul 2022 18:12:55 +0200 Message-Id: <20220721161302.156182-36-imbrenda@linux.ibm.com> X-Mailer: git-send-email 2.36.1 In-Reply-To: <20220721161302.156182-1-imbrenda@linux.ibm.com> References: <20220721161302.156182-1-imbrenda@linux.ibm.com> X-TM-AS-GCONF: 00 X-Proofpoint-ORIG-GUID: v7MJWUStj9xGskrMpRK4kzZAokYRpNl2 X-Proofpoint-GUID: wF5PsK9WELc15hs3FJRtR11x1GqYQj8C X-Proofpoint-UnRewURL: 0 URL was un-rewritten MIME-Version: 1.0 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=2022-07-21_22,2022-07-20_01,2022-06-22_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 adultscore=0 mlxlogscore=999 malwarescore=0 clxscore=1015 impostorscore=0 phishscore=0 suspectscore=0 bulkscore=0 spamscore=0 lowpriorityscore=0 priorityscore=1501 mlxscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2206140000 definitions=main-2207210061 Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org Add an mmu_notifier for protected VMs. The callback function is triggered when the mm is torn down, and will attempt to convert all protected vCPUs to non-protected. This allows the mm teardown to use the destroy page UVC instead of export. Also make KVM select CONFIG_MMU_NOTIFIER, needed to use mmu_notifiers. Signed-off-by: Claudio Imbrenda Acked-by: Janosch Frank Reviewed-by: Nico Boehr Link: https://lore.kernel.org/r/20220628135619.32410-10-imbrenda@linux.ibm.com Message-Id: <20220628135619.32410-10-imbrenda@linux.ibm.com> [frankja@linux.ibm.com: Conflict resolution for mmu_notifier.h include and struct kvm_s390_pv] Signed-off-by: Janosch Frank --- arch/s390/include/asm/kvm_host.h | 2 ++ arch/s390/kvm/Kconfig | 1 + arch/s390/kvm/kvm-s390.c | 10 ++++++++++ arch/s390/kvm/pv.c | 26 ++++++++++++++++++++++++++ 4 files changed, 39 insertions(+) diff --git a/arch/s390/include/asm/kvm_host.h b/arch/s390/include/asm/kvm_host.h index fca4fcf72a2a..6f9fc8bb0303 100644 --- a/arch/s390/include/asm/kvm_host.h +++ b/arch/s390/include/asm/kvm_host.h @@ -20,6 +20,7 @@ #include #include #include +#include #include #include #include @@ -929,6 +930,7 @@ struct kvm_s390_pv { unsigned long stor_base; void *stor_var; bool dumping; + struct mmu_notifier mmu_notifier; }; struct kvm_arch{ diff --git a/arch/s390/kvm/Kconfig b/arch/s390/kvm/Kconfig index 2e84d3922f7c..33f4ff909476 100644 --- a/arch/s390/kvm/Kconfig +++ b/arch/s390/kvm/Kconfig @@ -34,6 +34,7 @@ config KVM select SRCU select KVM_VFIO select INTERVAL_TREE + select MMU_NOTIFIER help Support hosting paravirtualized guest machines using the SIE virtualization capability on the mainframe. This should work diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c index d10c3b163cdc..5b77c43fbb01 100644 --- a/arch/s390/kvm/kvm-s390.c +++ b/arch/s390/kvm/kvm-s390.c @@ -31,6 +31,7 @@ #include #include #include +#include #include #include @@ -3198,6 +3199,15 @@ void kvm_arch_destroy_vm(struct kvm *kvm) */ if (kvm_s390_pv_get_handle(kvm)) kvm_s390_pv_deinit_vm(kvm, &rc, &rrc); + /* + * Remove the mmu notifier only when the whole KVM VM is torn down, + * and only if one was registered to begin with. If the VM is + * currently not protected, but has been previously been protected, + * then it's possible that the notifier is still registered. + */ + if (kvm->arch.pv.mmu_notifier.ops) + mmu_notifier_unregister(&kvm->arch.pv.mmu_notifier, kvm->mm); + debug_unregister(kvm->arch.dbf); free_page((unsigned long)kvm->arch.sie_page2); if (!kvm_is_ucontrol(kvm)) diff --git a/arch/s390/kvm/pv.c b/arch/s390/kvm/pv.c index d18c5ccfa5dc..c063d1a9cf04 100644 --- a/arch/s390/kvm/pv.c +++ b/arch/s390/kvm/pv.c @@ -15,6 +15,7 @@ #include #include #include +#include #include "kvm-s390.h" static void kvm_s390_clear_pv_state(struct kvm *kvm) @@ -188,6 +189,26 @@ int kvm_s390_pv_deinit_vm(struct kvm *kvm, u16 *rc, u16 *rrc) return -EIO; } +static void kvm_s390_pv_mmu_notifier_release(struct mmu_notifier *subscription, + struct mm_struct *mm) +{ + struct kvm *kvm = container_of(subscription, struct kvm, arch.pv.mmu_notifier); + u16 dummy; + + /* + * No locking is needed since this is the last thread of the last user of this + * struct mm. + * When the struct kvm gets deinitialized, this notifier is also + * unregistered. This means that if this notifier runs, then the + * struct kvm is still valid. + */ + kvm_s390_cpus_from_pv(kvm, &dummy, &dummy); +} + +static const struct mmu_notifier_ops kvm_s390_pv_mmu_notifier_ops = { + .release = kvm_s390_pv_mmu_notifier_release, +}; + int kvm_s390_pv_init_vm(struct kvm *kvm, u16 *rc, u16 *rrc) { struct uv_cb_cgc uvcb = { @@ -229,6 +250,11 @@ int kvm_s390_pv_init_vm(struct kvm *kvm, u16 *rc, u16 *rrc) return -EIO; } kvm->arch.gmap->guest_handle = uvcb.guest_handle; + /* Add the notifier only once. No races because we hold kvm->lock */ + if (kvm->arch.pv.mmu_notifier.ops != &kvm_s390_pv_mmu_notifier_ops) { + kvm->arch.pv.mmu_notifier.ops = &kvm_s390_pv_mmu_notifier_ops; + mmu_notifier_register(&kvm->arch.pv.mmu_notifier, kvm->mm); + } return 0; }