Ira Weiny wrote:
> If the firmware has configured CXL event support to be firmware first
> the OS can process those events through CPER records. The CXL layer has
> unique DPA to HPA knowledge and standard event trace parsing in place.
>
> CPER records contain Bus, Device, Function information which can be used
> to identify the PCI device which is sending the event.
>
> Change the PCI driver registration to include registration of a CXL
> CPER callback to process events through the trace subsystem.
>
> Use new scoped based management to simplify the handling of the PCI
> device object.
>
> NOTE this patch depends on Dan's addition of a device guard[1].
Now that you added guard(pci_dev) earlier in the series you can just use
that here rather than guard(device).
[..]
> +#define CXL_EVENT_HDR_FLAGS_REC_SEVERITY GENMASK(1, 0)
> +static void cxl_cper_event_call(enum cxl_event_type ev_type,
> + struct cxl_cper_event_rec *rec)
> +{
> + struct cper_cxl_event_devid *device_id = &rec->hdr.device_id;
> + struct pci_dev *pdev __free(pci_dev_put) = NULL;
> + enum cxl_event_log_type log_type;
> + struct cxl_dev_state *cxlds;
> + unsigned int devfn;
> + u32 hdr_flags;
> +
> + devfn = PCI_DEVFN(device_id->device_num, device_id->func_num);
> + pdev = pci_get_domain_bus_and_slot(device_id->segment_num,
> + device_id->bus_num, devfn);
> + if (!pdev)
> + return;
> +
> + guard(device)(&pdev->dev);
Per above:
guard(pci_dev)(pdev);
> + if (pdev->driver != &cxl_pci_driver)
> + return;
> +
> + cxlds = pci_get_drvdata(pdev);
> + if (!cxlds)
> + return;
> +
> + /* Fabricate a log type */
> + hdr_flags = get_unaligned_le24(rec->event.generic.hdr.flags);
> + log_type = FIELD_GET(CXL_EVENT_HDR_FLAGS_REC_SEVERITY, hdr_flags);
> +
> + cxl_event_trace_record(cxlds->cxlmd, log_type, ev_type,
> + &uuid_null, &rec->event);
> +}
> +
> +static int __init cxl_pci_driver_init(void)
> +{
> + int rc;
> +
> + rc = pci_register_driver(&cxl_pci_driver);
> + if (rc)
> + return rc;
> +
> + rc = cxl_cper_register_callback(cxl_cper_event_call);
> + if (rc)
> + pci_unregister_driver(&cxl_pci_driver);
I think this order should be flipped. That way any errors that might
arrive due to activity caused by probing have a chance to be serviced.
Any that fire while initial probing is happening will pause in
cxl_cper_event_call() and wait for probing to complete. Of course if
probing fails, all is lost, but I think there is some incremental
benefit to trying to catch those early records for things that are not
probing fatal.
