On 6/12/2025 6:36 AM, Jonathan Cameron wrote:
> On Tue, 3 Jun 2025 12:22:27 -0500
> Terry Bowman <terry.bowman@xxxxxxx> wrote:
>
>> The AER driver is now designed to forward CXL protocol errors to the CXL
>> driver. Update the CXL driver with functionality to dequeue the forwarded
>> CXL error from the kfifo. Also, update the CXL driver to begin the protocol
>> error handling processing using the work received from the FIFO.
>>
>> Introduce function cxl_prot_err_work_fn() to dequeue work forwarded by the
>> AER service driver. This will begin the CXL protocol error processing
>> with a call to cxl_handle_prot_error().
>>
>> Update cxl/core/ras.c by adding cxl_rch_handle_error_iter() that was
>> previously in the AER driver.
>>
>> Introduce sbdf_to_pci() to take the SBDF values from 'struct cxl_prot_error_info'
>> and use in discovering the erring PCI device. Make scope based reference
>> increments/decrements for the discovered PCI device and the associated
>> CXL device.
>>
>> Implement cxl_handle_prot_error() to differentiate between Restricted CXL
>> Host (RCH) protocol errors and CXL virtual host (VH) protocol errors.
>> RCH errors will be processed with a call to walk the associated Root
>> Complex Event Collector's (RCEC) secondary bus looking for the Root Complex
>> Integrated Endpoint (RCiEP) to handle the RCH error. Export pcie_walk_rcec()
>> so the CXL driver can walk the RCEC's downstream bus, searching for
>> the RCiEP.
>>
>> VH correctable error (CE) processing will call the CXL CE handler. VH
>> uncorrectable errors (UCE) will call cxl_do_recovery(), implemented as a
>> stub for now and to be updated in future patch. Export pci_aer_clean_fatal_status()
>> and pci_clean_device_status() used to clean up AER status after handling.
>>
>> Signed-off-by: Terry Bowman <terry.bowman@xxxxxxx>
> Hopefully I haven't duplicated existing feedback. A few more minor things
> inline.
>
>> +
>> +static struct pci_dev *sbdf_to_pci(struct cxl_prot_error_info *err_info)
> That's an odd function name as the sbdf is buried.
> Unless it's going to get a lot of use, I'd just put the lookup
> inline and not have a 'hard to name' function. With other suggested
> changes you only need (at where this is currently called)
> struct pci_dev *pdev __free(pci_dev_put) =
> pci_get_domain_bus_and_slot(err_info->segment, err_info->bus,
> err_info->devfn);
Ok. I'll remove the helper and add inline.
>> +{
>> + unsigned int devfn = PCI_DEVFN(err_info->device,
>> + err_info->function);
> This makes me wonder if you should have just use devfn inside the err_info.
> Is there a good reason to split them up before storing them?
>
> IIRC ARI makes a mess anyway of their meaning when separate.
Agreed. I'll keep devfn together.
>> + struct pci_dev *pdev __free(pci_dev_put) =
>> + pci_get_domain_bus_and_slot(err_info->segment,
>> + err_info->bus,
>> + devfn);
>> + return pdev;
>> +}
>> +
>> +static void cxl_handle_prot_error(struct cxl_prot_error_info *err_info)
>> +{
>> + struct pci_dev *pdev __free(pci_dev_put) = pci_dev_get(sbdf_to_pci(err_info));
>> +
>> + if (!pdev) {
>> + pr_err("Failed to find the CXL device\n");
>> + return;
>> + }
>> +
>> + /*
>> + * Internal errors of an RCEC indicate an AER error in an
>> + * RCH's downstream port. Check and handle them in the CXL.mem
>> + * device driver.
>> + */
>> + if (pci_pcie_type(pdev) == PCI_EXP_TYPE_RC_EC)
>> + return pcie_walk_rcec(pdev, cxl_rch_handle_error_iter, err_info);
>> +
>> + if (err_info->severity == AER_CORRECTABLE) {
>> + int aer = pdev->aer_cap;
>> + struct cxl_dev_state *cxlds = pci_get_drvdata(pdev);
>> + struct device *dev __free(put_device) = get_device(&cxlds->cxlmd->dev);
>> +
>> + if (aer)
>> + pci_clear_and_set_config_dword(pdev,
>> + aer + PCI_ERR_COR_STATUS,
>> + 0, PCI_ERR_COR_INTERNAL);
>> +
>> + cxl_cor_error_detected(pdev);
>> +
>> + pcie_clear_device_status(pdev);
>> + } else {
>> + cxl_do_recovery(pdev);
>> + }
>> +}
>> +
>> static void cxl_prot_err_work_fn(struct work_struct *work)
>> {
>> + struct cxl_prot_err_work_data wd;
>> +
>> + while (cxl_prot_err_kfifo_get(&wd)) {
>> + struct cxl_prot_error_info *err_info = &wd.err_info;
>> +
>> + cxl_handle_prot_error(err_info);
> I'm not seeing value in the local variable.
> Ignore if this code changes later and that makes more sense!
It can be removed and simplified.
Thanks for reviewing.
-Terry
>> + }
>> }
>>
>> #else
