Re: [PATCH 4/4] acpi/ghes, cxl/pci: Trace FW-First CXL Protocol Errors

[Smita Koralahalli]

On 1/2/2024 12:27 PM, Ira Weiny wrote:
> Smita Koralahalli wrote:
> > When PCIe AER is in FW-First, OS should process CXL Protocol errors from
> > CPER records. These CPER records obtained from GHES module, will rely on
> > a registered callback to be notified to the CXL subsystem in order to be
> > processed.
> >
> > Call the existing cxl_cper_callback 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>
>
> [snip]
>
> >   int cxl_cper_register_callback(cxl_cper_callback callback)
> > diff --git a/drivers/cxl/core/pci.c b/drivers/cxl/core/pci.c
> > index 37e1652afbc7..da516982a625 100644
> > --- a/drivers/cxl/core/pci.c
> > +++ b/drivers/cxl/core/pci.c
> > @@ -6,6 +6,7 @@
> >   #include <linux/pci.h>
> >   #include <linux/pci-doe.h>
> >   #include <linux/aer.h>
> > +#include <linux/cper.h>
> >   #include <cxlpci.h>
> >   #include <cxlmem.h>
> >   #include <cxl.h>
> > @@ -836,6 +837,51 @@ void cxl_setup_parent_dport(struct device *host, struct cxl_dport *dport)
> >   }
> >   EXPORT_SYMBOL_NS_GPL(cxl_setup_parent_dport, CXL);
> >   
> > +#define CXL_AER_UNCORRECTABLE	0
> > +#define CXL_AER_CORRECTABLE	1
>
> Better defined as an enum?

Will change.

> > +
> > +int cper_severity_cxl_aer(int cper_severity)
>
> My gut says that it would be better to hide this conversion in the
> GHES/CPER code and send a more generic defined CXL_AER_* severity through.

Ok will change.

> > +{
> > +	switch (cper_severity) {
> > +	case CPER_SEV_RECOVERABLE:
> > +	case CPER_SEV_FATAL:
> > +		return CXL_AER_UNCORRECTABLE;
> > +	default:
> > +		return CXL_AER_CORRECTABLE;
> > +	}
> > +}
> > +
> > +void cxl_prot_err_trace_record(struct cxl_dev_state *cxlds,
> > +			       struct cxl_cper_rec_data *data)
> > +{
> > +	struct cper_cxl_event_sn *dev_serial_num =  &data->rec.hdr.dev_serial_num;
> > +	u32 status, fe;
> > +	int severity;
> > +
> > +	severity = cper_severity_cxl_aer(data->severity);
> > +
> > +	cxlds->serial = (((u64)dev_serial_num->upper_dw << 32) |
> > +			dev_serial_num->lower_dw);
>
> This permanently overwrites the serial number read from PCI...
>
> If the serial number does not match up or was not valid (per the check in
> the previous patch) lets add a warning.

Sure will add.

Thanks,
Smita

> AFAICT they should match.
>
> Ira
>
> [snip]