From nobody Tue Apr 7 00:25:09 2026 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 0D86AC433FE for ; Fri, 7 Oct 2022 09:50:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229634AbiJGJuf (ORCPT ); Fri, 7 Oct 2022 05:50:35 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46622 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229484AbiJGJu0 (ORCPT ); Fri, 7 Oct 2022 05:50:26 -0400 Received: from mx0b-001b2d01.pphosted.com (mx0b-001b2d01.pphosted.com [148.163.158.5]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D0FE18FD54; Fri, 7 Oct 2022 02:50:23 -0700 (PDT) Received: from pps.filterd (m0098417.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.17.1.5/8.17.1.5) with ESMTP id 2979krAR019435; Fri, 7 Oct 2022 09:50:12 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=sklmgDUMERqlDzjCiD0nFNyQwB/Fcgy2eHm6qe3R6mA=; b=n753fckrOfgRxWDCDb9j5v5tznObujXSOyb2Q/UbZOqxBCB+QHLH9KWOab8Nns+8m0Jl K7I7slFeMo7pqUzZpPKWgMBJmZCSrzXlbYRcKLBgSL60BGSV7U9B3HQYmntXB7rOcCwl yjimaH1ocvcsSrfp6T51yX9IhFb3VJxMw+gLbK9cdz0V82l8l40w5I8/ftclbHs3BM94 OYUMfdmb0hkcQrexS1Im82GSX2Jf3pWU4M8lM3QGE5F9ozp7fjsUsyQMjsQ+9Ygddbnj wOlw2J+NAn0JoQtWC1Ir7sPzk64SS4tI23ux0/sqGSfNzUSmLXb+Xpg4Wv8LsIvoZU/T lQ== Received: from ppma02fra.de.ibm.com (47.49.7a9f.ip4.static.sl-reverse.com [159.122.73.71]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 3k2hsj81v0-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Fri, 07 Oct 2022 09:50:11 +0000 Received: from pps.filterd (ppma02fra.de.ibm.com [127.0.0.1]) by ppma02fra.de.ibm.com (8.16.1.2/8.16.1.2) with SMTP id 2979ZVtp019672; Fri, 7 Oct 2022 09:50:10 GMT Received: from b06cxnps4074.portsmouth.uk.ibm.com (d06relay11.portsmouth.uk.ibm.com [9.149.109.196]) by ppma02fra.de.ibm.com with ESMTP id 3jxd68p737-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Fri, 07 Oct 2022 09:50:10 +0000 Received: from d06av23.portsmouth.uk.ibm.com (d06av23.portsmouth.uk.ibm.com [9.149.105.59]) by b06cxnps4074.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 2979o6BX63242710 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Fri, 7 Oct 2022 09:50:06 GMT Received: from d06av23.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id CC798A4040; Fri, 7 Oct 2022 09:50:06 +0000 (GMT) Received: from d06av23.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 5A23DA404D; Fri, 7 Oct 2022 09:50:06 +0000 (GMT) Received: from tuxmaker.boeblingen.de.ibm.com (unknown [9.152.85.9]) by d06av23.portsmouth.uk.ibm.com (Postfix) with ESMTP; Fri, 7 Oct 2022 09:50:06 +0000 (GMT) From: Niklas Schnelle To: Matthew Rosato , Pierre Morel , iommu@lists.linux.dev Cc: linux-s390@vger.kernel.org, borntraeger@linux.ibm.com, hca@linux.ibm.com, gor@linux.ibm.com, gerald.schaefer@linux.ibm.com, agordeev@linux.ibm.com, svens@linux.ibm.com, joro@8bytes.org, will@kernel.org, robin.murphy@arm.com, jgg@nvidia.com, linux-kernel@vger.kernel.org Subject: [PATCH v6 1/6] iommu/s390: Fix duplicate domain attachments Date: Fri, 7 Oct 2022 11:50:00 +0200 Message-Id: <20221007095005.2017126-2-schnelle@linux.ibm.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20221007095005.2017126-1-schnelle@linux.ibm.com> References: <20221007095005.2017126-1-schnelle@linux.ibm.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-TM-AS-GCONF: 00 X-Proofpoint-ORIG-GUID: Fb4RTMEZ1rwf00mpNJeuAXapRIFcUCli X-Proofpoint-GUID: Fb4RTMEZ1rwf00mpNJeuAXapRIFcUCli X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.205,Aquarius:18.0.895,Hydra:6.0.528,FMLib:17.11.122.1 definitions=2022-10-06_05,2022-10-06_02,2022-06-22_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 bulkscore=0 priorityscore=1501 mlxscore=0 malwarescore=0 lowpriorityscore=0 suspectscore=0 phishscore=0 spamscore=0 mlxlogscore=999 adultscore=0 impostorscore=0 clxscore=1015 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2209130000 definitions=main-2210070058 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" Since commit fa7e9ecc5e1c ("iommu/s390: Tolerate repeat attach_dev calls") we can end up with duplicates in the list of devices attached to a domain. This is inefficient and confusing since only one domain can actually be in control of the IOMMU translations for a device. Fix this by detaching the device from the previous domain, if any, on attach. Add a WARN_ON() in case we still have attached devices on freeing the domain. While here remove the re-attach on failure dance as it was determined to be unlikely to help and may confuse debug and recovery. Fixes: fa7e9ecc5e1c ("iommu/s390: Tolerate repeat attach_dev calls") Signed-off-by: Niklas Schnelle Reviewed-by: Matthew Rosato --- v5->v6: - Only set zdev->dma_table once zpci_register_ioat() succeeded (Matt) v4->v5: - Unregister IOAT and set zdev->dma_table on error (Matt) drivers/iommu/s390-iommu.c | 106 ++++++++++++++++--------------------- 1 file changed, 45 insertions(+), 61 deletions(-) diff --git a/drivers/iommu/s390-iommu.c b/drivers/iommu/s390-iommu.c index c898bcbbce11..96173cfee324 100644 --- a/drivers/iommu/s390-iommu.c +++ b/drivers/iommu/s390-iommu.c @@ -79,10 +79,36 @@ static void s390_domain_free(struct iommu_domain *domai= n) { struct s390_domain *s390_domain =3D to_s390_domain(domain); =20 + WARN_ON(!list_empty(&s390_domain->devices)); dma_cleanup_tables(s390_domain->dma_table); kfree(s390_domain); } =20 +static void __s390_iommu_detach_device(struct zpci_dev *zdev) +{ + struct s390_domain *s390_domain =3D zdev->s390_domain; + struct s390_domain_device *domain_device, *tmp; + unsigned long flags; + + if (!s390_domain) + return; + + spin_lock_irqsave(&s390_domain->list_lock, flags); + list_for_each_entry_safe(domain_device, tmp, &s390_domain->devices, + list) { + if (domain_device->zdev =3D=3D zdev) { + list_del(&domain_device->list); + kfree(domain_device); + break; + } + } + spin_unlock_irqrestore(&s390_domain->list_lock, flags); + + zpci_unregister_ioat(zdev, 0); + zdev->s390_domain =3D NULL; + zdev->dma_table =3D NULL; +} + static int s390_iommu_attach_device(struct iommu_domain *domain, struct device *dev) { @@ -90,7 +116,7 @@ static int s390_iommu_attach_device(struct iommu_domain = *domain, struct zpci_dev *zdev =3D to_zpci_dev(dev); struct s390_domain_device *domain_device; unsigned long flags; - int cc, rc; + int cc, rc =3D 0; =20 if (!zdev) return -ENODEV; @@ -99,24 +125,18 @@ static int s390_iommu_attach_device(struct iommu_domai= n *domain, if (!domain_device) return -ENOMEM; =20 - if (zdev->dma_table && !zdev->s390_domain) { - cc =3D zpci_dma_exit_device(zdev); - if (cc) { - rc =3D -EIO; - goto out_free; - } - } - if (zdev->s390_domain) - zpci_unregister_ioat(zdev, 0); + __s390_iommu_detach_device(zdev); + else if (zdev->dma_table) + zpci_dma_exit_device(zdev); =20 - zdev->dma_table =3D s390_domain->dma_table; cc =3D zpci_register_ioat(zdev, 0, zdev->start_dma, zdev->end_dma, - virt_to_phys(zdev->dma_table)); + virt_to_phys(s390_domain->dma_table)); if (cc) { rc =3D -EIO; - goto out_restore; + goto out_free; } + zdev->dma_table =3D s390_domain->dma_table; =20 spin_lock_irqsave(&s390_domain->list_lock, flags); /* First device defines the DMA range limits */ @@ -127,9 +147,9 @@ static int s390_iommu_attach_device(struct iommu_domain= *domain, /* Allow only devices with identical DMA range limits */ } else if (domain->geometry.aperture_start !=3D zdev->start_dma || domain->geometry.aperture_end !=3D zdev->end_dma) { - rc =3D -EINVAL; spin_unlock_irqrestore(&s390_domain->list_lock, flags); - goto out_restore; + rc =3D -EINVAL; + goto out_unregister; } domain_device->zdev =3D zdev; zdev->s390_domain =3D s390_domain; @@ -138,14 +158,9 @@ static int s390_iommu_attach_device(struct iommu_domai= n *domain, =20 return 0; =20 -out_restore: - if (!zdev->s390_domain) { - zpci_dma_init_device(zdev); - } else { - zdev->dma_table =3D zdev->s390_domain->dma_table; - zpci_register_ioat(zdev, 0, zdev->start_dma, zdev->end_dma, - virt_to_phys(zdev->dma_table)); - } +out_unregister: + zpci_unregister_ioat(zdev, 0); + zdev->dma_table =3D NULL; out_free: kfree(domain_device); =20 @@ -155,32 +170,12 @@ static int s390_iommu_attach_device(struct iommu_doma= in *domain, static void s390_iommu_detach_device(struct iommu_domain *domain, struct device *dev) { - struct s390_domain *s390_domain =3D to_s390_domain(domain); struct zpci_dev *zdev =3D to_zpci_dev(dev); - struct s390_domain_device *domain_device, *tmp; - unsigned long flags; - int found =3D 0; =20 - if (!zdev) - return; + WARN_ON(zdev->s390_domain !=3D to_s390_domain(domain)); =20 - spin_lock_irqsave(&s390_domain->list_lock, flags); - list_for_each_entry_safe(domain_device, tmp, &s390_domain->devices, - list) { - if (domain_device->zdev =3D=3D zdev) { - list_del(&domain_device->list); - kfree(domain_device); - found =3D 1; - break; - } - } - spin_unlock_irqrestore(&s390_domain->list_lock, flags); - - if (found && (zdev->s390_domain =3D=3D s390_domain)) { - zdev->s390_domain =3D NULL; - zpci_unregister_ioat(zdev, 0); - zpci_dma_init_device(zdev); - } + __s390_iommu_detach_device(zdev); + zpci_dma_init_device(zdev); } =20 static struct iommu_device *s390_iommu_probe_device(struct device *dev) @@ -193,24 +188,13 @@ static struct iommu_device *s390_iommu_probe_device(s= truct device *dev) static void s390_iommu_release_device(struct device *dev) { struct zpci_dev *zdev =3D to_zpci_dev(dev); - struct iommu_domain *domain; =20 /* - * This is a workaround for a scenario where the IOMMU API common code - * "forgets" to call the detach_dev callback: After binding a device - * to vfio-pci and completing the VFIO_SET_IOMMU ioctl (which triggers - * the attach_dev), removing the device via - * "echo 1 > /sys/bus/pci/devices/.../remove" won't trigger detach_dev, - * only release_device will be called via the BUS_NOTIFY_REMOVED_DEVICE - * notifier. - * - * So let's call detach_dev from here if it hasn't been called before. + * release_device is expected to detach any domain currently attached + * to the device, but keep it attached to other devices in the group. */ - if (zdev && zdev->s390_domain) { - domain =3D iommu_get_domain_for_dev(dev); - if (domain) - s390_iommu_detach_device(domain, dev); - } + if (zdev) + __s390_iommu_detach_device(zdev); } =20 static int s390_iommu_update_trans(struct s390_domain *s390_domain, --=20 2.34.1