Also posted a QEMU series utilizing these kernel patches https://lore.kernel.org/qemu-devel/20250813174152.1238-1-alifm@xxxxxxxxxxxxx/ Thanks Farhan On 8/13/2025 10:08 AM, Farhan Ali wrote:
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 specific memory region for s390 vfio pci devices. Userspace can then read the memory region to obtain the error information and take appropriate actions such as driving a device reset. The memory region provides some flexibility in providing more information in the future if required. I would appreciate some feedback on this approach. Thanks Farhan Farhan Ali (6): s390/pci: Restore airq unconditionally for the zPCI device s390/pci: Update the logic for detecting passthrough device s390/pci: Store PCI error information for passthrough devices vfio-pci/zdev: Setup a zpci memory region for error information vfio-pci/zdev: Perform platform specific function reset for zPCI vfio: Allow error notification and recovery for ISM device arch/s390/include/asm/pci.h | 29 +++++++ arch/s390/pci/pci.c | 2 + arch/s390/pci/pci_event.c | 107 ++++++++++++++----------- arch/s390/pci/pci_irq.c | 3 +- drivers/vfio/pci/vfio_pci_core.c | 22 +++++- drivers/vfio/pci/vfio_pci_intrs.c | 2 +- drivers/vfio/pci/vfio_pci_priv.h | 8 ++ drivers/vfio/pci/vfio_pci_zdev.c | 126 +++++++++++++++++++++++++++++- include/uapi/linux/vfio.h | 2 + include/uapi/linux/vfio_zdev.h | 5 ++ 10 files changed, 253 insertions(+), 53 deletions(-)
