From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mx0a-001b2d01.pphosted.com (mx0a-001b2d01.pphosted.com [148.163.156.1]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E56D53ED112; Mon, 16 Mar 2026 19:15:58 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=148.163.156.1 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773688560; cv=none; b=OSIz6qO3ZphGG9e081xRPk6B1qZ6iJSixfw5r5tMGYN9avQUmOeeV5rZirWA9qATSnIHMzllkJzdvfLcwXJVInHoyNh5cZxk/ObKMARXEUwIvByZF61b3twfnnXIdJlJq8od4FoO+SDPeeCnrh7vsZfpcB1siCkYEdxpF7wqoHI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773688560; c=relaxed/simple; bh=RrzNQr3LTU9nXXH8ksu89D494Xkq2E2/UWWysh8wcbY=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=nkgRBa7XqaTXSvi3mcWh7moB7225g3ASOz5H1M/AtB0rmuSEsiaOAnnoQ6ZeCZLa/3ksT/6XSACtMOArl0JwJYiVbQDN2rKXJhiBQSM78A3whpz34xIUhW1DXYZBoI2UCu4dSl9QmXk2ckLQ/Gl0nYUcLI8+yCNJfiyORoyKFq4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.ibm.com; spf=pass smtp.mailfrom=linux.ibm.com; dkim=pass (2048-bit key) header.d=ibm.com header.i=@ibm.com header.b=CjaLFLGU; arc=none smtp.client-ip=148.163.156.1 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.ibm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.ibm.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=ibm.com header.i=@ibm.com header.b="CjaLFLGU" Received: from pps.filterd (m0356517.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.18.1.11/8.18.1.11) with ESMTP id 62GHFZCC1394708; Mon, 16 Mar 2026 19:15:52 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ibm.com; h=cc :content-transfer-encoding:date:from:message-id:mime-version :subject:to; s=pp1; bh=s/yLF+Ppn8uHvsXFQdCyrBoP6mVUz94kdDTWt35Ji Qg=; b=CjaLFLGUd1oUAJRcKLQ1jZCEghvXEbm2wbTnb8zhMmY5SLGrcwwu9Dx/P yYuk2WqCa3qQ7Gf3F80FyLpF0W7Kf1CZl4VXREj+3fVZcpDd4ySJlzxGGTNWq2ip oYklVyDP/uKFi+MUYpXvq8e4TNE5ZDF0eDRaCjAQpkG5owuWwv2u6R7rkq+9ZWzx oOxPIuFr0VcNd7V0LWoTUKENZ/9CY0Gndc+ZTGoWfF22b8bkkUuRBP6asfyfN0UR t3rvv4FSWIbBGI129WjH/5auuJy8ZYMysbqCHomB9HGt6wefOFZJWtffUNGZyLaB hKnJVu7O1b0VjN3NFJUKuRBD/xCXg== Received: from ppma23.wdc07v.mail.ibm.com (5d.69.3da9.ip4.static.sl-reverse.com [169.61.105.93]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 4cx7vfbp4r-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Mon, 16 Mar 2026 19:15:51 +0000 (GMT) Received: from pps.filterd (ppma23.wdc07v.mail.ibm.com [127.0.0.1]) by ppma23.wdc07v.mail.ibm.com (8.18.1.2/8.18.1.2) with ESMTP id 62GFmFLe028785; Mon, 16 Mar 2026 19:15:50 GMT Received: from smtprelay04.wdc07v.mail.ibm.com ([172.16.1.71]) by ppma23.wdc07v.mail.ibm.com (PPS) with ESMTPS id 4cwkgk602q-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Mon, 16 Mar 2026 19:15:50 +0000 Received: from smtpav01.wdc07v.mail.ibm.com (smtpav01.wdc07v.mail.ibm.com [10.39.53.228]) by smtprelay04.wdc07v.mail.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 62GJFnuH22806824 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 16 Mar 2026 19:15:49 GMT Received: from smtpav01.wdc07v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 5FAB258055; Mon, 16 Mar 2026 19:15:49 +0000 (GMT) Received: from smtpav01.wdc07v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 1760A5804B; Mon, 16 Mar 2026 19:15:48 +0000 (GMT) Received: from IBM-D32RQW3.ibm.com (unknown [9.61.241.131]) by smtpav01.wdc07v.mail.ibm.com (Postfix) with ESMTP; Mon, 16 Mar 2026 19:15:47 +0000 (GMT) From: Farhan Ali To: linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org Cc: helgaas@kernel.org, lukas@wunner.de, alex@shazbot.org, kbusch@kernel.org, clg@redhat.com, stable@vger.kernel.org, alifm@linux.ibm.com, schnelle@linux.ibm.com, mjrosato@linux.ibm.com Subject: [PATCH v11 0/9] Error recovery for vfio-pci devices on s390x Date: Mon, 16 Mar 2026 12:15:35 -0700 Message-ID: <20260316191544.2279-1-alifm@linux.ibm.com> X-Mailer: git-send-email 2.43.0 Precedence: bulk X-Mailing-List: linux-pci@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 X-Proofpoint-ORIG-GUID: CwiEzP66N32uiDvPiAXy_IEAwso8vbWH X-Authority-Analysis: v=2.4 cv=KajfcAYD c=1 sm=1 tr=0 ts=69b856e8 cx=c_pps a=3Bg1Hr4SwmMryq2xdFQyZA==:117 a=3Bg1Hr4SwmMryq2xdFQyZA==:17 a=Yq5XynenixoA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=U7nrCbtTmkRpXpFmAIza:22 a=VwQbUJbxAAAA:8 a=VnNF1IyMAAAA:8 a=LUPJ9KGWmwPqNv77U3kA:9 X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwMzE2MDE1MyBTYWx0ZWRfX/Cl4TTpEiTvv oHXDngPenSgdts3W3g49M4vxcDsZPQGcqq6EIclivv4HbqigD/Y0xVo/NAzSOOxzv5XN7RqgA/y FIPGCdXQx76BpIpNET66HYnXHPRWhe9fDKehcF75j0f/BuSLeclccByPiGgmBU/3dkMevJ30iBZ 03YWvL+ngDv1BeyPYYjiAj4o/mFMw7uhqMLAoobAvQcsvicQvwrSkzESyABecwXzGwwxKky/LAT PqYXnuZRQa14zLcpqmt4ZMNhB13gsKo6xoOtKS8RdAcSgRJGWV5MnDm1JX8ER07lYhPdMj/gHn/ ES9trIXzM6PrJwaEUun8FYPUBpT/j56n4rGXT4E/5VuO8k+amLr3mMMWU/jUIT/5NsvrJqVrh7L L2WLuiEjcBdgWuKQUb6iKNbVAzwCOxYJn15jKTLc18GCgu7wWiCEPuK+vhWWQkrBqRkmI96+VJW dfLK8OhHVJihj00ErmA== X-Proofpoint-GUID: CwiEzP66N32uiDvPiAXy_IEAwso8vbWH X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1143,Hydra:6.1.51,FMLib:17.12.100.49 definitions=2026-03-16_05,2026-03-16_06,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 suspectscore=0 adultscore=0 spamscore=0 malwarescore=0 clxscore=1015 impostorscore=0 bulkscore=0 lowpriorityscore=0 priorityscore=1501 phishscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2603050001 definitions=main-2603160153 Hi, This Linux kernel patch series introduces support for error recovery for passthrough PCI devices on System Z (s390x). Background ---------- For PCI devices on s390x an operating system receives platform specific error events from firmware rather than through AER.Today for passthrough/userspace devices, we don't attempt any error recovery and ignore any error events for the devices. The passthrough/userspace devices are managed by the vfio-pci driver. The driver does register error handling callbacks (error_detected), and on an error trigger an eventfd to userspace. But we need a mechanism to notify userspace (QEMU/guest/userspace drivers) about the error event. Proposal -------- We can expose this error information (currently only the PCI Error Code) via a device feature. Userspace can then obtain the error information via VFIO_DEVICE_FEATURE ioctl and take appropriate actions such as driving a device reset. This is how a typical flow for passthrough devices to a VM would work: For passthrough devices to a VM, the driver bound to the device on the host is vfio-pci. vfio-pci driver does support the error_detected() callback (vfio_pci_core_aer_err_detected()), and on an PCI error s390x recovery code on the host will call the vfio-pci error_detected() callback. The vfio-pci error_detected() callback will notify userspace/QEMU via an eventfd, and return PCI_ERS_RESULT_CAN_RECOVER. At this point the s390x error recovery on the host will skip any further action(see patch 6) and let userspace drive the error recovery. Once userspace/QEMU is notified, it then injects this error into the VM so device drivers in the VM can take recovery actions. For example for a passthrough NVMe device, the VM's OS NVMe driver will access the device. At this point the VM's NVMe driver's error_detected() will drive the recovery by returning PCI_ERS_RESULT_NEED_RESET, and the s390x error recovery in the VM's OS will try to do a reset. Resets are privileged operations and so the VM will need intervention from QEMU to perform the reset. QEMU will invoke the VFIO_DEVICE_RESET ioctl to now notify the host that the VM is requesting a reset of the device. The vfio-pci driver on the host will then perform the reset on the device to recover it. Thanks Farhan ChangeLog --------- v10 series https://lore.kernel.org/all/20260302203325.3826-1-alifm@linux.ibm.com/ v10 -> v11 - Rebase on pci/next to handle merge conflicts with patch 1. - Typo fixup in commit message (patch 4) and use guard() for mutex (patch 6). v9 series https://lore.kernel.org/all/20260217182257.1582-1-alifm@linux.ibm.com/ v9 -> v10 - Change pci_slot number to u16 (patch 1). - Avoid saving invalid config space state if config space is inaccessible in the device reset path. It uses the same patch as in v8 with R-b from Niklas. - Rebase on 7.0.0-rc2 v8 series https://lore.kernel.org/all/20260122194437.1903-1-alifm@linux.ibm.com/ v8 -> v9 - Avoid saving PCI config space state in reset path (patch 3) (suggested by Bjorn) - Add explicit version to struct vfio_device_feature_zpci_err (patch 7). - Rebase on 6.19 v7 series https://lore.kernel.org/all/20260107183217.1365-1-alifm@linux.ibm.com/ v7 -> v8 - Rebase on 6.19-rc4 - Address feedback from Niklas and Julien. v6 series https://lore.kernel.org/all/2c609e61-1861-4bf3-b019-a11c137d26a5@linux.ibm.com/ v6 -> v7 - Rebase on 6.19-rc4 - Update commit message based on Niklas's suggestion (patch 3). v5 series https://lore.kernel.org/all/20251113183502.2388-1-alifm@linux.ibm.com/ v5 -> v6 - Rebase on 6.18 + Lukas's PCI: Universal error recoverability of devices series (https://lore.kernel.org/all/cover.1763483367.git.lukas@wunner.de/) - Re-work config space accessibility check to pci_dev_save_and_disable() (patch 3). This avoids saving the config space, in the reset path, if the device's config space is corrupted or inaccessible. v4 series https://lore.kernel.org/all/20250924171628.826-1-alifm@linux.ibm.com/ v4 -> v5 - Rebase on 6.18-rc5 - Move bug fixes to the beginning of the series (patch 1 and 2). These patches were posted as a separate fixes series https://lore.kernel.org/all/a14936ac-47d6-461b-816f-0fd66f869b0f@linux.ibm.com/ - Add matching pci_put_dev() for pci_get_slot() (patch 6). v3 series https://lore.kernel.org/all/20250911183307.1910-1-alifm@linux.ibm.com/ v3 -> v4 - Remove warn messages for each PCI capability not restored (patch 1) - Check PCI_COMMAND and PCI_STATUS register for error value instead of device id (patch 1) - Fix kernel crash in patch 3 - Added reviewed by tags - Address comments from Niklas's (patches 4, 5, 7) - Fix compilation error non s390x system (patch 8) - Explicitly align struct vfio_device_feature_zpci_err (patch 8) v2 series https://lore.kernel.org/all/20250825171226.1602-1-alifm@linux.ibm.com/ v2 -> v3 - Patch 1 avoids saving any config space state if the device is in error (suggested by Alex) - Patch 2 adds additional check only for FLR reset to try other function reset method (suggested by Alex). - Patch 3 fixes a bug in s390 for resetting PCI devices with multiple functions. Creates a new flag pci_slot to allow per function slot. - Patch 4 fixes a bug in s390 for resource to bus address translation. - Rebase on 6.17-rc5 v1 series https://lore.kernel.org/all/20250813170821.1115-1-alifm@linux.ibm.com/ v1 - > v2 - Patches 1 and 2 adds some additional checks for FLR/PM reset to try other function reset method (suggested by Alex). - Patch 3 fixes a bug in s390 for resetting PCI devices with multiple functions. - Patch 7 adds a new device feature for zPCI devices for the VFIO_DEVICE_FEATURE ioctl. The ioctl is used by userspace to retriece any PCI error information for the device (suggested by Alex). - Patch 8 adds a reset_done() callback for the vfio-pci driver, to restore the state of the device after a reset. - Patch 9 removes the pcie check for triggering VFIO_PCI_ERR_IRQ_INDEX. Farhan Ali (9): PCI: Allow per function PCI slots s390/pci: Add architecture specific resource/bus address translation PCI: Avoid saving config space state if inaccessible PCI: Add additional checks for flr reset s390/pci: Update the logic for detecting passthrough device s390/pci: Store PCI error information for passthrough devices vfio-pci/zdev: Add a device feature for error information vfio: Add a reset_done callback for vfio-pci driver vfio: Remove the pcie check for VFIO_PCI_ERR_IRQ_INDEX arch/s390/include/asm/pci.h | 29 ++++++++ arch/s390/pci/pci.c | 75 +++++++++++++++++++++ arch/s390/pci/pci_event.c | 106 +++++++++++++++++------------- drivers/pci/host-bridge.c | 8 +-- drivers/pci/pci.c | 26 +++++++- drivers/pci/slot.c | 31 +++++++-- drivers/vfio/pci/vfio_pci_core.c | 22 +++++-- drivers/vfio/pci/vfio_pci_intrs.c | 3 +- drivers/vfio/pci/vfio_pci_priv.h | 9 +++ drivers/vfio/pci/vfio_pci_zdev.c | 47 ++++++++++++- include/linux/pci.h | 5 +- include/uapi/linux/vfio.h | 17 +++++ 12 files changed, 307 insertions(+), 71 deletions(-) -- 2.43.0