From mboxrd@z Thu Jan 1 00:00:00 1970 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 56825C433FE for ; Tue, 4 Oct 2022 12:08:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230088AbiJDMHz (ORCPT ); Tue, 4 Oct 2022 08:07:55 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36286 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230058AbiJDMHl (ORCPT ); Tue, 4 Oct 2022 08:07:41 -0400 Received: from mx0b-001b2d01.pphosted.com (mx0b-001b2d01.pphosted.com [148.163.158.5]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3598153D00; Tue, 4 Oct 2022 05:07:31 -0700 (PDT) Received: from pps.filterd (m0127361.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.17.1.5/8.17.1.5) with ESMTP id 294C0SYn008258; Tue, 4 Oct 2022 12:07:12 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ibm.com; h=from : to : cc : subject : date : message-id : content-transfer-encoding : mime-version; s=pp1; bh=fBncFGSXBZfP/viIIxsNuvBu7rLPffx97OOoAIh8UYc=; b=cCB+VKHLs7V181pi3VMsdK9xoBLWZb2KsEaxbppSM9hYCGnIVxcy1NH+Qrq7q4Bh6nIL m7bMd8uaS7vwx3ZFowZFirQ4UahDmFtRjF/KFlOlzxAGFpsyaGBWMZMmrxwhyZqR1LUV c0l7PIOQctx4Gd8WLxrtEMJeXEelcKhVFboxGcSHaK3++D3ahLUk3frjRdczGN9rHyFf bJ1vq1iF1Hn2MRE/CWFHzP9yG1SS+puMxxioaW9XPIfOvfZC+Uaem7RMgORGgugM/rvv /1l1ZDUaCWqxgRwcSS88skbJCF4VnGj9V5rCMfCyA5kKU2HGx0CmR1WNu7HJW8exkb0j jg== Received: from ppma01fra.de.ibm.com (46.49.7a9f.ip4.static.sl-reverse.com [159.122.73.70]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 3k0fca96be-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Tue, 04 Oct 2022 12:07:12 +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 294C5f6S028122; Tue, 4 Oct 2022 12:07:10 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 3jxd68tyjb-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Tue, 04 Oct 2022 12:07:10 +0000 Received: from d06av23.portsmouth.uk.ibm.com (d06av23.portsmouth.uk.ibm.com [9.149.105.59]) by b06cxnps4075.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 294C77WM66453762 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 4 Oct 2022 12:07:07 GMT Received: from d06av23.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id E5963A405D; Tue, 4 Oct 2022 12:07:06 +0000 (GMT) Received: from d06av23.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 783CDA4055; Tue, 4 Oct 2022 12:07:06 +0000 (GMT) Received: from tuxmaker.boeblingen.de.ibm.com (unknown [9.152.85.9]) by d06av23.portsmouth.uk.ibm.com (Postfix) with ESMTP; Tue, 4 Oct 2022 12:07:06 +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 v4 0/5] iommu/s390: Fixes related to attach and aperture handling Date: Tue, 4 Oct 2022 14:07:01 +0200 Message-Id: <20221004120706.2957492-1-schnelle@linux.ibm.com> X-Mailer: git-send-email 2.34.1 X-TM-AS-GCONF: 00 X-Proofpoint-GUID: Bqzj9r0CP2tmcWNn872Or66k1nyr3XHF X-Proofpoint-ORIG-GUID: Bqzj9r0CP2tmcWNn872Or66k1nyr3XHF Content-Transfer-Encoding: 8bit X-Proofpoint-UnRewURL: 0 URL was un-rewritten MIME-Version: 1.0 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.205,Aquarius:18.0.895,Hydra:6.0.528,FMLib:17.11.122.1 definitions=2022-10-04_04,2022-09-29_03,2022-06-22_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 mlxscore=0 clxscore=1015 malwarescore=0 impostorscore=0 bulkscore=0 phishscore=0 priorityscore=1501 adultscore=0 mlxlogscore=999 suspectscore=0 lowpriorityscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2209130000 definitions=main-2210040078 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi All, This is v4 of a follow up to Matt's recent series[0] where he tackled a race that turned out to be outside of the s390 IOMMU driver itself as well as duplicate device attachments. After an internal discussion we came up with what I believe is a cleaner fix. Instead of actively checking for duplicates we instead detach from any previous domain on attach. From my cursory reading of the code this seems to be what the Intel IOMMU driver is doing as well. Moreover we drop the attempt to re-attach the device to its previous IOMMU domain on failure. This was fragile, unlikely to help and unexpected for calling code. Thanks Jason for the suggestion. During development of this fix we realized that we can get rid of struct s390_domain_device entirely if we instead thread the list through the attached struct zpci_devs. This saves us from having to allocate during attach and gets rid of one level of indirection during IOMMU operations. Additionally 3 more fixes have been added in v3 that weren't in v2 of this series. One is for a potential situation where the aperture of a domain could shrink and leave invalid translations. The next one fixes an off by one in checking validity of an IOVA and the last one fixes a wrong value for pgsize_bitmap. *Note*: This series is against the s390 features branch[1] which already contains the bus_next field removal that was part of v2. Best regards, Niklas Changes since v3: - Drop s390_domain from __s390_iommu_detach_device() (Jason) - WARN_ON() mismatched domain in s390_iommu_detach_device() (Jason) - Use __s390_iommu_detach_device() in s390_iommu_release_device() (Jason) - Make aperture check resistant against overflow (Jason) Changes since v2: - The patch removing the unused bus_next field has been spun out and already made it into the s390 feature branch on git.kernel.org - Make __s390_iommu_detach_device() return void (Jason) - Remove the re-attach on failure dance as it is unlikely to help and complicates debug and recovery (Jason) - Ignore attempts to detach from domain that is not the active one - Add patch to fix potential shrinking of the aperture and use reserved ranges per device instead of the aperture to respect IOVA range restrictions (Jason) - Add a fix for an off by one error on checking an IOVA against the aperture - Add a fix for wrong pgsize_bitmap Changes since v1: - After patch 3 we don't have to search in the devices list on detach as we alreadz have hold of the zpci_dev (Jason) - Add a WARN_ON() if somehow ended up detaching a device from a domain that isn't the device's current domain. - Removed the iteration and list delete from s390_domain_free() instead just WARN_ON() when we're freeing without having detached - The last two points should help catching sequencing errors much more quickly in the future. [0] https://lore.kernel.org/linux-iommu/20220831201236.77595-1-mjrosato@linux.ibm.com/ [1] https://git.kernel.org/pub/scm/linux/kernel/git/s390/linux.git/ Niklas Schnelle (5): iommu/s390: Fix duplicate domain attachments iommu/s390: Get rid of s390_domain_device iommu/s390: Fix potential s390_domain aperture shrinking iommu/s390: Fix incorrect aperture check iommu/s390: Fix incorrect pgsize_bitmap arch/s390/include/asm/pci.h | 1 + drivers/iommu/s390-iommu.c | 169 +++++++++++++++--------------------- 2 files changed, 70 insertions(+), 100 deletions(-) -- 2.34.1