Re: [PATCH v15 7/9] cxl: Update Endpoint AER uncorrectable handler

Dave Jiang
2026-02-03T17:31:38Z

On 2/2/26 7:52 PM, Terry Bowman wrote:
> CXL drivers now implement protocol RAS support. PCI protocol errors,
> however, continue to be reported via the AER capability and must still be
> handled by a PCI error recovery callback.
>
> Replace the existing cxl_error_detected() callback in cxl/pci.c with a
> new cxl_pci_error_detected() implementation that handles only uncorrectable
> PCI protocol errors reported through AER.

Do we need to explain why only uncorrectable is handled?

>
> Introduce helper named cxl_handler_aer() amd implement to handle and
> log the CXL device's AER error.
>
> This cleanly separates CXL protocol error handling from PCI AER handling
> and ensures that each subsystem processes only the errors it is
> responsible.
>
> Signed-off-by: Terry Bowman <terry.bowman@amd.com>
>
> ---
>
> Changes in v14->v15:
> - Title update (Terry)
> - Change cxl_pci_error-detected() to handle & log AER (Terry)
> - Update commit message (Terry)
> - Moved cxl_handle_ras()/cxl_handle_cor_ras() to earlier patch (Terry)
>
> Changes in v13->v14:
> - Update commit headline (Bjorn)
> - Rename pci_error_detected()/pci_cor_error_detected() ->
> cxl_pci_error_detected/cxl_pci_cor_error_detected() (Jonathan)
> - Remove now-invalid comment in cxl_error_detected() (Jonathan)
> - Split into separate patches for UCE and CE (Terry)
>
> Changes in v12->v13:
> - Update commit messaqge (Terry)
> - Updated all the implementation and commit message. (Terry)
> - Refactored cxl_cor_error_detected()/cxl_error_detected() to remove
> pdev (Dave Jiang)
>
> Changes in v11->v12:
> - None
>
> Changes in v10->v11:
> - cxl_error_detected() - Change handlers' scoped_guard() to guard() (Jonathan)
> - cxl_error_detected() - Remove extra line (Shiju)
> - Changes moved to core/ras.c (Terry)
> - cxl_error_detected(), remove 'ue' and return with function call. (Jonathan)
> - Remove extra space in documentation for PCI_ERS_RESULT_PANIC definition
> - Move #include "pci.h from cxl.h to core.h (Terry)
> - Remove unnecessary includes of cxl.h and core.h in mem.c (Terry)
> ---
> drivers/cxl/core/ras.c | 68 +++++++++++++++---------------------------
> drivers/cxl/cxlpci.h | 9 +++---
> drivers/cxl/pci.c | 6 ++--
> 3 files changed, 31 insertions(+), 52 deletions(-)
>
> diff --git a/drivers/cxl/core/ras.c b/drivers/cxl/core/ras.c
> index 970ff3df442c..061e6aaec176 100644
> --- a/drivers/cxl/core/ras.c
> +++ b/drivers/cxl/core/ras.c
> @@ -441,55 +441,35 @@ void cxl_cor_error_detected(struct pci_dev *pdev)
> }
> EXPORT_SYMBOL_NS_GPL(cxl_cor_error_detected, "CXL");
>
> -pci_ers_result_t cxl_error_detected(struct pci_dev *pdev,
> - pci_channel_state_t state)
> +static bool cxl_handle_aer(struct pci_dev *pdev)

For a function that returns a bool, the function name doesn't sound quite right. Maybe cxl_uncor_aer_present()?

DJ

> {
> - struct cxl_dev_state *cxlds = pci_get_drvdata(pdev);
> - struct cxl_memdev *cxlmd = cxlds->cxlmd;
> - struct device *dev = &cxlmd->dev;
> - bool ue;
> -
> - scoped_guard(device, dev) {
> - if (!dev->driver) {
> - dev_warn(&pdev->dev,
> - "%s: memdev disabled, abort error handling\n",
> - dev_name(dev));
> - return PCI_ERS_RESULT_DISCONNECT;
> - }
> + struct aer_capability_regs aer;
> + u32 aer_cap = pdev->aer_cap;
>
> - if (cxlds->rcd)
> - cxl_handle_rdport_errors(cxlds);
> - /*
> - * A frozen channel indicates an impending reset which is fatal to
> - * CXL.mem operation, and will likely crash the system. On the off
> - * chance the situation is recoverable dump the status of the RAS
> - * capability registers and bounce the active state of the memdev.
> - */
> - ue = cxl_handle_ras(&cxlds->cxlmd->dev, cxlds->serial,
> - cxlmd->endpoint->regs.ras);
> + if (!aer_cap) {
> + pr_warn_ratelimited("%s: AER capability isn't present\n",
> + pci_name(pdev));
> + return false;
> }
>
> - switch (state) {
> - case pci_channel_io_normal:
> - if (ue) {
> - device_release_driver(dev);
> - return PCI_ERS_RESULT_NEED_RESET;
> - }
> - return PCI_ERS_RESULT_CAN_RECOVER;
> - case pci_channel_io_frozen:
> - dev_warn(&pdev->dev,
> - "%s: frozen state error detected, disable CXL.mem\n",
> - dev_name(dev));
> - device_release_driver(dev);
> - return PCI_ERS_RESULT_NEED_RESET;
> - case pci_channel_io_perm_failure:
> - dev_warn(&pdev->dev,
> - "failure state error detected, request disconnect\n");
> - return PCI_ERS_RESULT_DISCONNECT;
> - }
> - return PCI_ERS_RESULT_NEED_RESET;
> + pci_read_config_dword(pdev, aer_cap + PCI_ERR_UNCOR_STATUS, &aer.uncor_status);
> + pci_read_config_dword(pdev, aer_cap + PCI_ERR_UNCOR_MASK, &aer.uncor_mask);
> +
> + /* The AER driver logged the error */
> + pci_aer_clear_nonfatal_status(pdev);
> + pci_aer_clear_fatal_status(pdev);
> +
> + return (aer.uncor_status & aer.uncor_mask);
> +}
> +
> +pci_ers_result_t cxl_pci_error_detected(struct pci_dev *pdev,
> + pci_channel_state_t error)
> +{
> + u32 rc = cxl_handle_aer(pdev);
> +
> + return rc ? PCI_ERS_RESULT_DISCONNECT : PCI_ERS_RESULT_CAN_RECOVER;
> }
> -EXPORT_SYMBOL_NS_GPL(cxl_error_detected, "CXL");
> +EXPORT_SYMBOL_NS_GPL(cxl_pci_error_detected, "CXL");
>
> static void cxl_handle_proto_error(struct cxl_proto_err_work_data *err_info)
> {
> diff --git a/drivers/cxl/cxlpci.h b/drivers/cxl/cxlpci.h
> index 970add0256e9..5534422b496c 100644
> --- a/drivers/cxl/cxlpci.h
> +++ b/drivers/cxl/cxlpci.h
> @@ -79,15 +79,14 @@ void read_cdat_data(struct cxl_port *port);
>
> #ifdef CONFIG_CXL_RAS
> void cxl_cor_error_detected(struct pci_dev *pdev);
> -pci_ers_result_t cxl_error_detected(struct pci_dev *pdev,
> - pci_channel_state_t state);
> void devm_cxl_dport_rch_ras_setup(struct cxl_dport *dport);
> +pci_ers_result_t cxl_pci_error_detected(struct pci_dev *pdev,
> + pci_channel_state_t error);
> void devm_cxl_port_ras_setup(struct cxl_port *port);
> #else
> static inline void cxl_cor_error_detected(struct pci_dev *pdev) { }
> -
> -static inline pci_ers_result_t cxl_error_detected(struct pci_dev *pdev,
> - pci_channel_state_t state)
> +static inline pci_ers_result_t cxl_pci_error_detected(struct pci_dev *pdev,
> + pci_channel_state_t state)
> {
> return PCI_ERS_RESULT_NONE;
> }
> diff --git a/drivers/cxl/pci.c b/drivers/cxl/pci.c
> index acb0eb2a13c3..ff741adc7c7f 100644
> --- a/drivers/cxl/pci.c
> +++ b/drivers/cxl/pci.c
> @@ -1051,8 +1051,8 @@ static void cxl_reset_done(struct pci_dev *pdev)
> }
> }
>
> -static const struct pci_error_handlers cxl_error_handlers = {
> - .error_detected = cxl_error_detected,
> +static const struct pci_error_handlers pci_error_handlers = {
> + .error_detected = cxl_pci_error_detected,
> .slot_reset = cxl_slot_reset,
> .resume = cxl_error_resume,
> .cor_error_detected = cxl_cor_error_detected,
> @@ -1063,7 +1063,7 @@ static struct pci_driver cxl_pci_driver = {
> .name = KBUILD_MODNAME,
> .id_table = cxl_mem_pci_tbl,
> .probe = cxl_pci_probe,
> - .err_handler = &cxl_error_handlers,
> + .err_handler = &pci_error_handlers,
> .dev_groups = cxl_rcd_groups,
> .driver = {
> .probe_type = PROBE_PREFER_ASYNCHRONOUS,