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{ "id": 2197365, "url": "http://patchwork.ozlabs.org/api/1.0/covers/2197365/?format=api", "project": { "id": 28, "url": "http://patchwork.ozlabs.org/api/1.0/projects/28/?format=api", "name": "Linux PCI development", "link_name": "linux-pci", "list_id": "linux-pci.vger.kernel.org", "list_email": "linux-pci@vger.kernel.org", "web_url": null, "scm_url": null, "webscm_url": null }, "msgid": "<20260217182257.1582-1-alifm@linux.ibm.com>", "date": "2026-02-17T18:22:48", "name": "[v9,0/9] Error recovery for vfio-pci devices on s390x", "submitter": { "id": 73785, "url": "http://patchwork.ozlabs.org/api/1.0/people/73785/?format=api", "name": "Farhan Ali", "email": "alifm@linux.ibm.com" }, "series": [ { "id": 492470, "url": "http://patchwork.ozlabs.org/api/1.0/series/492470/?format=api", "date": "2026-02-17T18:22:49", "name": "Error recovery for vfio-pci devices on s390x", "version": 9, "mbox": "http://patchwork.ozlabs.org/series/492470/mbox/" } ], "headers": { "Return-Path": "\n <linux-pci+bounces-47493-incoming=patchwork.ozlabs.org@vger.kernel.org>", "X-Original-To": [ "incoming@patchwork.ozlabs.org", "linux-pci@vger.kernel.org" ], "Delivered-To": "patchwork-incoming@legolas.ozlabs.org", "Authentication-Results": [ "legolas.ozlabs.org;\n\tdkim=pass (2048-bit key;\n unprotected) header.d=ibm.com header.i=@ibm.com header.a=rsa-sha256\n header.s=pp1 header.b=U6rO1cjs;\n\tdkim-atps=neutral", "legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org\n (client-ip=2600:3c04:e001:36c::12fc:5321; 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d=ibm.com; h=cc\n\t:content-transfer-encoding:date:from:message-id:mime-version\n\t:subject:to; s=pp1; bh=uzO9tDWQ+GRhCS/fqnAxEWn4rY+zAi4maWYf1hC90\n\tkA=; b=U6rO1cjsjKyJxmU8+rAk4so6uLDf8V8JzDnIVw10rhcrxAUQ1C1XFQqRw\n\txoFCp1rV7wbyHqYn7Sk/4lddGUFVAOZpmteMKU3DDTboBp+WiiKGvxZ2nb0TMK04\n\tMy4+QDifHuRmsf/EFzhF1Pw3eSFua22RuY9OBAZo4EbVAjQqj1AzeX1XW++qdp49\n\t8MU3hM0Hl7utKTQVitoxmP9Ejq4wjzElA1u+8Fw3SWE28POHudHt3w/IVzNsqivc\n\tdIufG/U2nEZjyqmZnZt+RrZwy5dDBBeUgskjgx59bDpy3ZZsICZrH/2Ad6E/LiXI\n\tzrYgNbF9gIxJ9h/fsBQohKlqVnqww==", "From": "Farhan Ali <alifm@linux.ibm.com>", "To": "linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org,\n linux-pci@vger.kernel.org", "Cc": "helgaas@kernel.org, lukas@wunner.de, alex@shazbot.org, clg@redhat.com,\n stable@vger.kernel.org, alifm@linux.ibm.com, schnelle@linux.ibm.com,\n mjrosato@linux.ibm.com", "Subject": "[PATCH v9 0/9] Error recovery for vfio-pci devices on s390x", "Date": "Tue, 17 Feb 2026 10:22:48 -0800", "Message-ID": "<20260217182257.1582-1-alifm@linux.ibm.com>", "X-Mailer": "git-send-email 2.43.0", "Precedence": "bulk", "X-Mailing-List": "linux-pci@vger.kernel.org", "List-Id": "<linux-pci.vger.kernel.org>", "List-Subscribe": "<mailto:linux-pci+subscribe@vger.kernel.org>", "List-Unsubscribe": "<mailto:linux-pci+unsubscribe@vger.kernel.org>", "MIME-Version": "1.0", "Content-Transfer-Encoding": "8bit", "X-TM-AS-GCONF": "00", "X-Proofpoint-ORIG-GUID": "fSqjPOZsZ-r2a3efjqwc-AaiLdiigJPZ", "X-Authority-Analysis": "v=2.4 cv=Md9hep/f c=1 sm=1 tr=0 ts=6994b204 cx=c_pps\n a=aDMHemPKRhS1OARIsFnwRA==:117 a=aDMHemPKRhS1OARIsFnwRA==:17\n a=HzLeVaNsDn8A:10 a=VkNPw1HP01LnGYTKEx00:22 a=Mpw57Om8IfrbqaoTuvik:22\n a=GgsMoib0sEa3-_RKJdDe:22 a=VwQbUJbxAAAA:8 a=VnNF1IyMAAAA:8\n a=Qtm5l5LcizsofoGoYxAA:9", "X-Proofpoint-Spam-Details-Enc": "AW1haW4tMjYwMjE3MDE0OCBTYWx0ZWRfX6N9E4W++JKK/\n d+/whjCG5046vyyHDHUIm8YxKjtMzwUcw8YiUOvxwaWWn84+5uoQogmaO+QB2oesB7g2a080Oc/\n piRDen821aaxMAlCbVq0dUvjgS1mABxRJ1GLj2e0z3TCclGzYCqx5jeZh2w3yHRhsiStpq0+PEX\n dpL4X3rU/qSeQFAfSlopcS+SIU/KlfRG56yqQx4u5iluynRC478DlYRoBAxn5oHtJhV4cR+znq5\n 0V3JhLlI4MKOtGrVFHiIzTnrSKFMCFVX4Qcdf5c2dgYY8NGLwEEFf8UN9pEIGeZuhTYZ9iIlPX0\n oCur9MdVsW2BJ44qFOdbEwvmzI4U9Oyzg5fQ9PX/94kY8fVtIap7J+0sFZpptsOSAlLWBioyoCP\n PUnyio3Vi7cjW9j+BIIJAv8FKxnk9y4bR1LchfW/vTd9n+c/6M1JWhdh1DMAFaCebAyddzDvX3O\n 0D1k3piml1mKPaX179Q==", "X-Proofpoint-GUID": "fSqjPOZsZ-r2a3efjqwc-AaiLdiigJPZ", "X-Proofpoint-Virus-Version": "vendor=baseguard\n engine=ICAP:2.0.293,Aquarius:18.0.1121,Hydra:6.1.51,FMLib:17.12.100.49\n definitions=2026-02-17_03,2026-02-16_04,2025-10-01_01", "X-Proofpoint-Spam-Details": "rule=outbound_notspam policy=outbound score=0\n clxscore=1015 impostorscore=0 lowpriorityscore=0 spamscore=0 adultscore=0\n priorityscore=1501 suspectscore=0 malwarescore=0 phishscore=0 bulkscore=0\n classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0\n reason=mlx scancount=1 engine=8.22.0-2601150000 definitions=main-2602170148" }, "content": "Hi,\n\nThis Linux kernel patch series introduces support for error recovery for\npassthrough PCI devices on System Z (s390x). \n\nBackground\n----------\nFor PCI devices on s390x an operating system receives platform specific\nerror events from firmware rather than through AER.Today for\npassthrough/userspace devices, we don't attempt any error recovery and\nignore any error events for the devices. The passthrough/userspace devices\nare managed by the vfio-pci driver. The driver does register error handling\ncallbacks (error_detected), and on an error trigger an eventfd to\nuserspace. But we need a mechanism to notify userspace\n(QEMU/guest/userspace drivers) about the error event. \n\nProposal\n--------\nWe can expose this error information (currently only the PCI Error Code)\nvia a device feature. Userspace can then obtain the error information \nvia VFIO_DEVICE_FEATURE ioctl and take appropriate actions such as driving \na device reset.\n\nThis is how a typical flow for passthrough devices to a VM would work:\nFor passthrough devices to a VM, the driver bound to the device on the host \nis vfio-pci. vfio-pci driver does support the error_detected() callback \n(vfio_pci_core_aer_err_detected()), and on an PCI error s390x recovery \ncode on the host will call the vfio-pci error_detected() callback. The \nvfio-pci error_detected() callback will notify userspace/QEMU via an \neventfd, and return PCI_ERS_RESULT_CAN_RECOVER. At this point the s390x \nerror recovery on the host will skip any further action(see patch 6) and \nlet userspace drive the error recovery.\n\nOnce userspace/QEMU is notified, it then injects this error into the VM \nso device drivers in the VM can take recovery actions. For example for a \npassthrough NVMe device, the VM's OS NVMe driver will access the device. \nAt this point the VM's NVMe driver's error_detected() will drive the \nrecovery by returning PCI_ERS_RESULT_NEED_RESET, and the s390x error \nrecovery in the VM's OS will try to do a reset. Resets are privileged \noperations and so the VM will need intervention from QEMU to perform the \nreset. QEMU will invoke the VFIO_DEVICE_RESET ioctl to now notify the \nhost that the VM is requesting a reset of the device. The vfio-pci driver \non the host will then perform the reset on the device to recover it.\n\n\nThanks\nFarhan\n\nChangeLog\n---------\nv8 series https://lore.kernel.org/all/20260122194437.1903-1-alifm@linux.ibm.com/\nv8 -> v9\n - Avoid saving PCI config space state in reset path (patch 3) (suggested by Bjorn)\n \n - Add explicit version to struct vfio_device_feature_zpci_err (patch 7).\n\n - Rebase on 6.19\n\n\nv7 series https://lore.kernel.org/all/20260107183217.1365-1-alifm@linux.ibm.com/\nv7 -> v8\n - Rebase on 6.19-rc4\n\n - Address feedback from Niklas and Julien.\n\n\nv6 series https://lore.kernel.org/all/2c609e61-1861-4bf3-b019-a11c137d26a5@linux.ibm.com/\nv6 -> v7\n - Rebase on 6.19-rc4\n\n - Update commit message based on Niklas's suggestion (patch 3).\n\nv5 series https://lore.kernel.org/all/20251113183502.2388-1-alifm@linux.ibm.com/\nv5 -> v6\n - Rebase on 6.18 + Lukas's PCI: Universal error recoverability of\n devices series (https://lore.kernel.org/all/cover.1763483367.git.lukas@wunner.de/)\n\n - Re-work config space accessibility check to pci_dev_save_and_disable() (patch 3).\n This avoids saving the config space, in the reset path, if the device's config space is\n corrupted or inaccessible.\n\nv4 series https://lore.kernel.org/all/20250924171628.826-1-alifm@linux.ibm.com/\nv4 -> v5\n - Rebase on 6.18-rc5\n\n - Move bug fixes to the beginning of the series (patch 1 and 2). These patches\n were posted as a separate fixes series \nhttps://lore.kernel.org/all/a14936ac-47d6-461b-816f-0fd66f869b0f@linux.ibm.com/\n\n - Add matching pci_put_dev() for pci_get_slot() (patch 6).\n\nv3 series https://lore.kernel.org/all/20250911183307.1910-1-alifm@linux.ibm.com/\nv3 -> v4\n - Remove warn messages for each PCI capability not restored (patch 1)\n\n - Check PCI_COMMAND and PCI_STATUS register for error value instead of device id \n (patch 1)\n\n - Fix kernel crash in patch 3\n\n - Added reviewed by tags\n\n - Address comments from Niklas's (patches 4, 5, 7)\n\n - Fix compilation error non s390x system (patch 8)\n\n - Explicitly align struct vfio_device_feature_zpci_err (patch 8)\n\n\nv2 series https://lore.kernel.org/all/20250825171226.1602-1-alifm@linux.ibm.com/\nv2 -> v3\n - Patch 1 avoids saving any config space state if the device is in error\n (suggested by Alex)\n\n - Patch 2 adds additional check only for FLR reset to try other function \n reset method (suggested by Alex).\n\n - Patch 3 fixes a bug in s390 for resetting PCI devices with multiple\n functions. Creates a new flag pci_slot to allow per function slot.\n\n - Patch 4 fixes a bug in s390 for resource to bus address translation.\n\n - Rebase on 6.17-rc5\n\n\nv1 series https://lore.kernel.org/all/20250813170821.1115-1-alifm@linux.ibm.com/\nv1 - > v2\n - Patches 1 and 2 adds some additional checks for FLR/PM reset to \n try other function reset method (suggested by Alex).\n\n - Patch 3 fixes a bug in s390 for resetting PCI devices with multiple\n functions.\n\n - Patch 7 adds a new device feature for zPCI devices for the VFIO_DEVICE_FEATURE \n ioctl. The ioctl is used by userspace to retriece any PCI error\n information for the device (suggested by Alex).\n\n - Patch 8 adds a reset_done() callback for the vfio-pci driver, to\n restore the state of the device after a reset.\n\n - Patch 9 removes the pcie check for triggering VFIO_PCI_ERR_IRQ_INDEX.\n\nFarhan Ali (9):\n PCI: Allow per function PCI slots\n s390/pci: Add architecture specific resource/bus address translation\n PCI: Avoid saving config space state in reset path\n PCI: Add additional checks for flr reset\n s390/pci: Update the logic for detecting passthrough device\n s390/pci: Store PCI error information for passthrough devices\n vfio-pci/zdev: Add a device feature for error information\n vfio: Add a reset_done callback for vfio-pci driver\n vfio: Remove the pcie check for VFIO_PCI_ERR_IRQ_INDEX\n\n arch/s390/include/asm/pci.h | 29 ++++++++\n arch/s390/pci/pci.c | 75 +++++++++++++++++++++\n arch/s390/pci/pci_event.c | 107 +++++++++++++++++-------------\n drivers/pci/host-bridge.c | 8 +--\n drivers/pci/pci.c | 44 ++++++------\n drivers/pci/slot.c | 25 ++++++-\n drivers/vfio/pci/vfio_pci_core.c | 22 ++++--\n drivers/vfio/pci/vfio_pci_intrs.c | 3 +-\n drivers/vfio/pci/vfio_pci_priv.h | 9 +++\n drivers/vfio/pci/vfio_pci_zdev.c | 47 ++++++++++++-\n include/linux/pci.h | 1 +\n include/uapi/linux/vfio.h | 17 +++++\n 12 files changed, 305 insertions(+), 82 deletions(-)" }