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 968F23D6465; Tue, 5 May 2026 20:05:19 +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=1778011521; cv=none; b=Dnr4OUHLH3CsvAwh6HbqaMnhuNpnIdiDuh9StFu8ngxyrjRiP3xW172sv/CHTKO/1wugd7k0nWemoSFteE+NvWr4EzcdKsR9G+6xuSe152cIPcSmjJmS3xfM5/iBhI+jC6K5OY1grhjE641drpxi2s2x463KAFwXTh5XNVrEomU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778011521; c=relaxed/simple; bh=OxrNVPWMOar/igoc0kzdRKgi2YjXHjsejeCP8GcY6Fo=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=LnhmCJSCnx6+ee2U3uGUpO2OSLIUCqvSgjsZ8afCwP0/7iPi/76nuZwwCHIpdSDz6fvjgy6KFQB+bOWayvHAMsibg6uHaRF8/PQWghvpeeEONH0P6PYvBYBCRZBE5xUONzg36/OWKU/j5tePGbcah5lqegucBD8mAFij/6hoFNc= 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=gS7oJTjU; 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="gS7oJTjU" Received: from pps.filterd (m0360083.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.18.1.11/8.18.1.11) with ESMTP id 645II9bn2606962; Tue, 5 May 2026 20:05:14 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=f9m8uZgl60NrXjuBZMnFmGaI9h6MtJWWa2rNTm/Vh 88=; b=gS7oJTjUl1AfloEHTxwkQ85GQbAd640d9VNlaBv604b1H6BJj3Mz/u7vx odbIeuvKttDjsYRH98Y1hp902kLUkdxRJ33dEgI/okJ8yGRtZsm3aaY+n0PlVqsg 9IzmjsOf6Wj5wGu3+pyN84bH4wLhL2YH3LyJM/Mk1eI0+zb8bJAeaxbFl6g3sWZj ujeTZDqxQSpTGzY/7i/oEIkzgxLAQa9nOZJqD/dH8fhPopu4q4BkAvvfYlHKSCQr 0f+WpElFCjZsMe5eDpCB2Ae6xDpFan+GzfztbsNU9d71LYGDLMVV1+VCpEaAe7ZN 5cJ55yAUMMZi6tRPmUyaMENLFffQw== Received: from ppma21.wdc07v.mail.ibm.com (5b.69.3da9.ip4.static.sl-reverse.com [169.61.105.91]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 4dw9v7dkur-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Tue, 05 May 2026 20:05:13 +0000 (GMT) Received: from pps.filterd (ppma21.wdc07v.mail.ibm.com [127.0.0.1]) by ppma21.wdc07v.mail.ibm.com (8.18.1.7/8.18.1.7) with ESMTP id 645JsbEI019201; Tue, 5 May 2026 20:05:12 GMT Received: from smtprelay04.wdc07v.mail.ibm.com ([172.16.1.71]) by ppma21.wdc07v.mail.ibm.com (PPS) with ESMTPS id 4dwvkju83g-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Tue, 05 May 2026 20:05:12 +0000 (GMT) Received: from smtpav06.dal12v.mail.ibm.com (smtpav06.dal12v.mail.ibm.com [10.241.53.105]) by smtprelay04.wdc07v.mail.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 645K5B8h35979836 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 5 May 2026 20:05:11 GMT Received: from smtpav06.dal12v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 49C2C5805D; Tue, 5 May 2026 20:05:11 +0000 (GMT) Received: from smtpav06.dal12v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 873D358043; Tue, 5 May 2026 20:05:10 +0000 (GMT) Received: from IBM-D32RQW3.ibm.com (unknown [9.61.242.219]) by smtpav06.dal12v.mail.ibm.com (Postfix) with ESMTP; Tue, 5 May 2026 20:05:10 +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, alex@shazbot.org, alifm@linux.ibm.com, schnelle@linux.ibm.com, mjrosato@linux.ibm.com Subject: [PATCH v15 0/7] Error recovery for vfio-pci devices on s390x Date: Tue, 5 May 2026 13:05:03 -0700 Message-ID: <20260505200510.2954-1-alifm@linux.ibm.com> X-Mailer: git-send-email 2.43.0 Precedence: bulk X-Mailing-List: linux-s390@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwNTA1MDE5MSBTYWx0ZWRfXwW96ap90qzZn 7qbY6tf7wp4hWvQ3nlMJsXgQQVN0a1efZi1vULs6+bkc57f4qPoVwF0lGPNd04ucLNjR6ngN6x1 LuQGPRpC5GigA4Jtaq4MNBGo5cqUmi5PA2HW256eZQV/0IH9rSdkUb7Qb1/pr8+pxUHoRjN7CKk 6BTRyEysMir3Vijc7U4371OKxRcwGlIri2BNXHKTQJmOBHIEBL1nlAt8Gfa3M45tAKA+ZqLZIm+ BXlsaBQvuXC5zepV5sV65KvsEX2D+aCx/Zdm/daJIAxZ4ZpeNgZvMQdg835xmtyzfvs+NnmVOAa ZL4QWcGnjSRGgS9Mv1vB5u5bJ8JfFKt7exGjlgmzT4ZaflCq9o6+4VrHtycDYKOodcSkSc3AVMl 1wYYtGSseQDeNdG0asZKKyBoEMPpUt3jTyujP6nq/Fga/m3C8tBcb9G6PLPEd4Mme/cyinmEA8r sPL/xWCW3UCif9uZ5fQ== X-Proofpoint-GUID: o03peR38ZGDbbQqZZOUmZbkLthSy_ekV X-Proofpoint-ORIG-GUID: o03peR38ZGDbbQqZZOUmZbkLthSy_ekV X-Authority-Analysis: v=2.4 cv=eu/vCIpX c=1 sm=1 tr=0 ts=69fa4d7a cx=c_pps a=GFwsV6G8L6GxiO2Y/PsHdQ==:117 a=GFwsV6G8L6GxiO2Y/PsHdQ==:17 a=NGcC8JguVDcA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=iQ6ETzBq9ecOQQE5vZCe:22 a=VwQbUJbxAAAA:8 a=VnNF1IyMAAAA:8 a=4zu8aI-QVnT60ftJUTQA:9 a=O8hF6Hzn-FEA:10 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=2026-05-05_02,2026-04-30_02,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 phishscore=0 lowpriorityscore=0 clxscore=1015 adultscore=0 suspectscore=0 malwarescore=0 bulkscore=0 impostorscore=0 spamscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2604200000 definitions=main-2605050191 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 4) 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 --------- This only includes change log from last 5 revision. Older change log is available in v14 cover letter. v14 https://lore.kernel.org/all/20260421163031.704-1-alifm@linux.ibm.com/ v14 -> v15 - Fix issues identified by Sashiko (patch 4). - Address Niklas feedback (patch 4 and patch 5). - Rebase on 7.1-rc2. v13 series https://lore.kernel.org/all/20260413210608.2912-1-alifm@linux.ibm.com/ v13 -> v14 - Remove version from vfio uAPI struct. Instead reserve additional space and add a flags field. The flags will be used to indicate any usage of the reserved space (patch 5). - Remove pending_errors from vfio uAPI struct and instead return an error to indicate no more pending error for userspace to handle (patch 5). - Rebase on recent linux master v12 series https://lore.kernel.org/all/20260330174011.1161-1-alifm@linux.ibm.com/ v12 -> v13 - Add the mediated_recovery flag as part of struct zpci_ccdf_pending and protect the struct with pending_errs_lock (patch 4). - Move dequeing pending error logic to a helper function (patch 5). - Update device feature number for VFIO_DEVICE_FEATURE_ZPCI_ERROR (patch 5). - Rebase on linux-next with tag next-20260410 v11 series https://lore.kernel.org/all/20260316191544.2279-1-alifm@linux.ibm.com/ - Address Bjorn's comments from v11 (patches 1-3). - Create a common function to check config space accessibility (patch 2). - Address Alex's comments from v11 (patches 4, 5, 7). - Protect the mediated_recovery flag with the pending_errs_lock. Doing that it made sense to squash patches 5 and 6 from v11 (current patch 4). Even though the code didn't change significantly I have dropped R-b tags for it. Would appreciate another look at the patch (current patch 4). - Dropped arch specific pcibios_resource_to_bus and pcibios_bus_to_resource as its not needed for this series. Will address the issue as a standalone patch separate from this series. - Rebased on pci/next, with head at f8a1c947ccc6 ("Merge branch 'pci/misc'") 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). Farhan Ali (7): PCI: Allow per function PCI slots to fix slot reset on s390 PCI: Avoid saving config space state if inaccessible PCI: Fail FLR when config space is inaccessible s390/pci: Store PCI error information for passthrough devices vfio-pci/zdev: Add a device feature for error information vfio/pci: Add a reset_done callback for vfio-pci driver vfio/pci: Remove the pcie check for VFIO_PCI_ERR_IRQ_INDEX arch/s390/include/asm/pci.h | 32 +++++++ arch/s390/pci/pci.c | 1 + arch/s390/pci/pci_event.c | 133 ++++++++++++++++++------------ drivers/pci/hotplug/rpaphp_slot.c | 2 +- drivers/pci/pci.c | 32 ++++++- drivers/pci/slot.c | 33 ++++++-- 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 | 57 ++++++++++++- include/linux/pci.h | 8 +- include/uapi/linux/vfio.h | 30 +++++++ 12 files changed, 287 insertions(+), 75 deletions(-) -- 2.43.0