Smita Koralahalli wrote:
> When PCIe AER is in FW-First, OS should process CXL Protocol errors from
> CPER records.
>
> Reuse the existing work queue cxl_cper_work registered with GHES to notify
> the CXL subsystem on a Protocol error.
>
> The defined trace events cxl_aer_uncorrectable_error and
> cxl_aer_correctable_error currently trace native CXL AER errors. Reuse
> them to trace FW-First Protocol Errors.
>
> Signed-off-by: Smita Koralahalli <Smita.KoralahalliChannabasappa@xxxxxxx>
> ---
> v2:
> Removed pr_warn for serial number.
> p_err -> rec/p_rec.
> ---
> drivers/acpi/apei/ghes.c | 14 ++++++++++++++
> drivers/cxl/core/pci.c | 24 ++++++++++++++++++++++++
> drivers/cxl/cxlpci.h | 3 +++
> drivers/cxl/pci.c | 20 ++++++++++++++++++--
> include/cxl/event.h | 1 +
> 5 files changed, 60 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/acpi/apei/ghes.c b/drivers/acpi/apei/ghes.c
> index 9dcf0f78458f..5082885e1f2c 100644
> --- a/drivers/acpi/apei/ghes.c
> +++ b/drivers/acpi/apei/ghes.c
> @@ -723,6 +723,20 @@ static void cxl_cper_handle_prot_err(struct acpi_hest_generic_data *gdata)
>
> if (cxl_cper_handle_prot_err_info(gdata, &wd.p_rec))
> return;
> +
> + guard(spinlock_irqsave)(&cxl_cper_work_lock);
> +
> + if (!cxl_cper_work)
> + return;
> +
> + wd.event_type = CXL_CPER_EVENT_PROT_ERR;
> +
> + if (!kfifo_put(&cxl_cper_fifo, wd)) {
> + pr_err_ratelimited("CXL CPER kfifo overflow\n");
> + return;
> + }
> +
> + schedule_work(cxl_cper_work);
The cxl_cper_work item is only for cases where the cxl_pci driver might care
about annotating an error report with driver specific details like the
impacted kernel object name, 'struct cxl_memdev', or address translation
for DPA data.
Protocol errors that are not endpoint errors should never be placed in
the cxl_cper_fifo. That is exclusively for errors that cxl_pci needs to
consume.
My expectation is that similar to aer_recover_queue for PCIe protocol
errors CXL needs to grow a cxl_recover_queue that at a minimum triggers
new trace events to dump these records to RAS daemon.
I am struggling to think what useful information cxl_pci could ever
append to a protocol error event.
What is more likely is that later when Terry adds port error handling a
CPER protocol error record could trigger a new cxl_do_recovery() to
react to CXL topology errors that might impact downstream CXL devices.
In that case the notification will come through something like a new
'struct cxl_error_handlers *' hanging off 'struct pci_driver' since
accelerator drivers are going to have distinct error handling from
generic memory expanders.
