Received: by 2002:a05:6358:16cc:b0:ea:6187:17c9 with SMTP id r12csp6774569rwl; Mon, 9 Jan 2023 12:54:06 -0800 (PST) X-Google-Smtp-Source: AMrXdXvZnUDWbgeSpCUzW8thlJRP6grl6QlfD+nIRpml6TL0c/RoAoMxC00guqdfYj/CZm2uq/c0 X-Received: by 2002:a05:6402:150b:b0:493:a6eb:874f with SMTP id f11-20020a056402150b00b00493a6eb874fmr15138417edw.7.1673297646439; Mon, 09 Jan 2023 12:54:06 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; t=1673297646; cv=none; d=google.com; s=arc-20160816; b=T011qwhWPTjiprSmEj7zTIsHTvWHPx75GB6lsic7Je1It4PRA9/lzqvj65gWkINkPI F3o8pb9ATVcU7LnNbA6PgjDpmYRlgXUw7Xi491r2wOAYoTwEPBz4vUGC8MVsLeHO9kQ3 LENpwhx51o++Vw8pG+ilPptEdkgj2IZx8Vli7aO9qaCX98G3owq0Kt7fpLcKLkPgxAZ+ KMYqh2vdQC0qphs/ERSOXnO25rKqgKtv2ixRil5HSSSnFDgAiinpymOHXKfTbk5hbL4f LYt+dlrqSu6Xx9OP2DwyXP4NZEDwVEURMU/ukmLUgW+XF2gudJHQsna6beD5vafbvOek Ezlg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:content-transfer-encoding:mime-version :references:in-reply-to:message-id:date:subject:cc:to:from :dkim-signature; bh=WbMDgdUJZVKJs0Nl9/VYi0q97VLNPhEA1RGhIIXexw4=; b=mEMfCy4bzIWOeLSwEwF71RbUYg1kyguYlO98ZJAkIobbR02GQJfhRbBcTYy0uJ7ENz aIz6VcmujDv3CXmr8WGAPQPLN/AunyoIXZIcz4vkHMGo59FYl6bhxMo+XLz4aQwIuKWZ H7Iq4ZtJFufopO9v2hfsQ38BAvm3+9lk0a1MDbNcw0ypch/Wi6VKT3veK4ukE9hF+SQ2 2kdAQhIpv95jSGHgh5RShJVRUquCDC+F9iQyIVksXSZcP4flqePIIqpewrJK5TPT6NYT bSSyVDz/McB041PMrZ6/GBF7YnWl3d7/IVlvToEsqfAnY6B0NTCK6xbDj+i2oMuevxak hE0g== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@ibm.com header.s=pp1 header.b=tICUTTr2; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=REJECT sp=NONE dis=NONE) header.from=ibm.com Return-Path: Received: from out1.vger.email (out1.vger.email. [2620:137:e000::1:20]) by mx.google.com with ESMTP id q16-20020a056402519000b0048d06445a1asi11956198edd.286.2023.01.09.12.53.53; Mon, 09 Jan 2023 12:54:06 -0800 (PST) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; dkim=pass header.i=@ibm.com header.s=pp1 header.b=tICUTTr2; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=REJECT sp=NONE dis=NONE) header.from=ibm.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237770AbjAIUL2 (ORCPT + 53 others); Mon, 9 Jan 2023 15:11:28 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35014 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237565AbjAIULA (ORCPT ); Mon, 9 Jan 2023 15:11:00 -0500 Received: from mx0a-001b2d01.pphosted.com (mx0b-001b2d01.pphosted.com [148.163.158.5]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D71C7767F; Mon, 9 Jan 2023 12:10:53 -0800 (PST) Received: from pps.filterd (m0098416.ppops.net [127.0.0.1]) by mx0b-001b2d01.pphosted.com (8.17.1.19/8.17.1.19) with ESMTP id 309JuEd7007452; Mon, 9 Jan 2023 20:10:49 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=WbMDgdUJZVKJs0Nl9/VYi0q97VLNPhEA1RGhIIXexw4=; b=tICUTTr25xyQuaVIfVsGyhVM3CaIMsA4ASISY+XYNFT6hzBme/UIOlxZ367da1OIEEqr sOQ/n0nGWPCf9F0JptTssk+P0mma08DiuHwqn8IylSE6eKiV3feBtwcHCAiJY8BUNEoV jrI/ZfzfT1a8LEL3dtUdA2BWE9dxbQ39gf/fI+G6RInnWnY8MEhahe+O/UZXN3Ayzh62 8XmRJmBf8gIsbpnR4XX2bf6hkQO0c7X3PcwS3oZ1t39DBJlUVeihOfVgEQ6vmhtQY7Bt /ac8A9WUbhz3JvqDabAObQqr4Le03mkIuaqmv1zckMeszyksbl/YvE8se4SD8/ZywQDb zw== Received: from pps.reinject (localhost [127.0.0.1]) by mx0b-001b2d01.pphosted.com (PPS) with ESMTPS id 3myjw3qdqg-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Mon, 09 Jan 2023 20:10:48 +0000 Received: from m0098416.ppops.net (m0098416.ppops.net [127.0.0.1]) by pps.reinject (8.17.1.5/8.17.1.5) with ESMTP id 309Jt5o8015678; Mon, 9 Jan 2023 20:10:48 GMT Received: from ppma05wdc.us.ibm.com (1b.90.2fa9.ip4.static.sl-reverse.com [169.47.144.27]) by mx0b-001b2d01.pphosted.com (PPS) with ESMTPS id 3myjw3qdq5-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Mon, 09 Jan 2023 20:10:48 +0000 Received: from pps.filterd (ppma05wdc.us.ibm.com [127.0.0.1]) by ppma05wdc.us.ibm.com (8.17.1.19/8.17.1.19) with ESMTP id 309IIJIf007444; Mon, 9 Jan 2023 20:10:47 GMT Received: from smtprelay02.dal12v.mail.ibm.com ([9.208.130.97]) by ppma05wdc.us.ibm.com (PPS) with ESMTPS id 3my0c75qk1-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Mon, 09 Jan 2023 20:10:47 +0000 Received: from smtpav06.wdc07v.mail.ibm.com (smtpav06.wdc07v.mail.ibm.com [10.39.53.233]) by smtprelay02.dal12v.mail.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 309KAkr826804658 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 9 Jan 2023 20:10:46 GMT Received: from smtpav06.wdc07v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id DF68958054; Mon, 9 Jan 2023 20:10:45 +0000 (GMT) Received: from smtpav06.wdc07v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 815195803F; Mon, 9 Jan 2023 20:10:43 +0000 (GMT) Received: from li-2311da4c-2e09-11b2-a85c-c003041e9174.ibm.com.com (unknown [9.65.251.44]) by smtpav06.wdc07v.mail.ibm.com (Postfix) with ESMTP; Mon, 9 Jan 2023 20:10:43 +0000 (GMT) From: Matthew Rosato To: alex.williamson@redhat.com, pbonzini@redhat.com Cc: jgg@nvidia.com, cohuck@redhat.com, farman@linux.ibm.com, pmorel@linux.ibm.com, borntraeger@linux.ibm.com, frankja@linux.ibm.com, imbrenda@linux.ibm.com, david@redhat.com, akrowiak@linux.ibm.com, jjherne@linux.ibm.com, pasic@linux.ibm.com, zhenyuw@linux.intel.com, zhi.a.wang@intel.com, linux-s390@vger.kernel.org, kvm@vger.kernel.org, intel-gvt-dev@lists.freedesktop.org, intel-gfx@lists.freedesktop.org, linux-kernel@vger.kernel.org Subject: [PATCH 2/2] KVM: s390: pci: use asyncronous kvm put Date: Mon, 9 Jan 2023 15:10:37 -0500 Message-Id: <20230109201037.33051-3-mjrosato@linux.ibm.com> X-Mailer: git-send-email 2.39.0 In-Reply-To: <20230109201037.33051-1-mjrosato@linux.ibm.com> References: <20230109201037.33051-1-mjrosato@linux.ibm.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 X-Proofpoint-ORIG-GUID: Oy22cas3PYwW1KMUoEHNyWu-S5fSk_fC X-Proofpoint-GUID: uWY384HuphX1JMDaGrC_ZMgCEmJTwW4n X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.205,Aquarius:18.0.923,Hydra:6.0.545,FMLib:17.11.122.1 definitions=2023-01-09_14,2023-01-09_02,2022-06-22_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 mlxscore=0 malwarescore=0 lowpriorityscore=0 bulkscore=0 mlxlogscore=999 phishscore=0 spamscore=0 clxscore=1015 impostorscore=0 suspectscore=0 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2212070000 definitions=main-2301090141 X-Spam-Status: No, score=-2.0 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_EF,RCVD_IN_MSPIKE_H2,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org It's possible that the kvm refcount will reach 0 at this point while the associated device is still in kvm device list - this would result in a deadlock on the vfio group lock. Avoid this possibility by using kvm_put_kvm_async to do the kvm_destroy_vm asynchronously. Fixes: 09340b2fca00 ("KVM: s390: pci: add routines to start/stop interpretive execution") Signed-off-by: Matthew Rosato --- arch/s390/kvm/pci.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/arch/s390/kvm/pci.c b/arch/s390/kvm/pci.c index ec51e810e381..d1d528438138 100644 --- a/arch/s390/kvm/pci.c +++ b/arch/s390/kvm/pci.c @@ -509,7 +509,7 @@ static int kvm_s390_pci_register_kvm(void *opaque, struct kvm *kvm) kvm_s390_pci_dev_release(zdev); mutex_unlock(&kvm->lock); mutex_unlock(&zdev->kzdev_lock); - kvm_put_kvm(kvm); + kvm_put_kvm_async(kvm); return rc; } @@ -567,7 +567,11 @@ static void kvm_s390_pci_unregister_kvm(void *opaque) mutex_unlock(&kvm->lock); mutex_unlock(&zdev->kzdev_lock); - kvm_put_kvm(kvm); + /* + * Avoid possible deadlock on any currently-held vfio lock by + * ensuring the potential kvm_destroy_vm call is done asynchronously + */ + kvm_put_kvm_async(kvm); } void kvm_s390_pci_init_list(struct kvm *kvm) -- 2.39.0