Messages in this thread |  | | Date | Wed, 6 May 2026 10:20:13 -0700 | | Subject | Re: [PATCH v15 4/7] s390/pci: Store PCI error information for passthrough devices | | From | Farhan Ali <> |
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On 5/6/2026 2:38 AM, Niklas Schnelle wrote: >> -static pci_ers_result_t zpci_event_attempt_error_recovery(struct pci_dev *pdev) >> +static pci_ers_result_t zpci_event_attempt_error_recovery(struct pci_dev *pdev, >> + struct zpci_ccdf_err *ccdf) >> { >> pci_ers_result_t ers_res = PCI_ERS_RESULT_DISCONNECT; >> struct zpci_dev *zdev = to_zpci(pdev); >> @@ -194,13 +206,6 @@ static pci_ers_result_t zpci_event_attempt_error_recovery(struct pci_dev *pdev) >> } >> pdev->error_state = pci_channel_io_frozen; >> >> - if (is_passed_through(pdev)) { >> - pr_info("%s: Cannot be recovered in the host because it is a pass-through device\n", >> - pci_name(pdev)); >> - status_str = "failed (pass-through)"; >> - goto out_unlock; >> - } >> - >> driver = to_pci_driver(pdev->dev.driver); >> if (!is_driver_supported(driver)) { >> if (!driver) { >> @@ -216,12 +221,25 @@ static pci_ers_result_t zpci_event_attempt_error_recovery(struct pci_dev *pdev) >> goto out_unlock; >> } >> >> + zpci_store_pci_error(pdev, ccdf); > Sashiko notes that zdev->pendings_errs.mediated_recovery could become > true between the above zpci_store_pci_error() and the below check for > leaving recovery to user-space. I think we could make a general > improvement that also tackles this concern. The ideas is that we could > have zpci_store_pci_error() return true if it did store the error and > we are in mediated recovery mode. Then we use that as the signal to > skip host recovery below. That way we also don't need to retake the > pending_errs_lock which makes the below much simpler and it would be a > win independent of the race. As for the race this would make sure that > we either do the host recovery or store the error and let user-space > recover.
I did think of the concern about mediated_recovery becoming true after zpci_store_pci_error(), but IIUC in that case we won't even be able to deliver the error signal to userspace (via error_detected()). And I don't think mediated_recovery flag can be set to true. Since we are holding the pci device lock, vfio_pci_core_enable() will fail as it will fail trying to reset the device.
Thanks
Farhan
>> ers_res = zpci_event_notify_error_detected(pdev, driver); >> if (ers_result_indicates_abort(ers_res)) { >> status_str = "failed (abort on detection)"; >> goto out_unlock; >> } >> >> + mutex_lock(&zdev->pending_errs_lock); >> + if (zdev->pending_errs.mediated_recovery) { >> + pr_info("%s: Leaving recovery of pass-through device to user-space\n", >> + pci_name(pdev)); >> + ers_res = PCI_ERS_RESULT_RECOVERED; >> + status_str = "in progress"; >> + mutex_unlock(&zdev->pending_errs_lock); >> + goto out_unlock; >> + } >> + mutex_unlock(&zdev->pending_errs_lock);
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