Re: [PATCH v9 02/16] PCI/AER: Report CXL or PCIe bus error type in trace logging

[Sathyanarayanan Kuppuswamy <sathyanarayanan.kuppuswamy@linux.intel.com>]

On 6/4/25 7:32 AM, Bowman, Terry wrote:
>
> On 6/3/2025 5:02 PM, Sathyanarayanan Kuppuswamy wrote:
>> On 6/3/25 10:22 AM, Terry Bowman wrote:
>>> The AER service driver and aer_event tracing currently log 'PCIe Bus Type'
>>> for all errors. Update the driver and aer_event tracing to log 'CXL Bus
>>> Type' for CXL device errors.
>>>
>>> This requires the AER can identify and distinguish between PCIe errors and
>>> CXL errors.
>>>
>>> Introduce boolean 'is_cxl' to 'struct aer_err_info'. Add assignment in
>>> aer_get_device_error_info() and pci_print_aer().
>>>
>>> Update the aer_event trace routine to accept a bus type string parameter.
>>>
>>> Signed-off-by: Terry Bowman <terry.bowman@amd.com>
>>> Reviewed-by: Ira Weiny <ira.weiny@intel.com>
>>> ---
>>>    drivers/pci/pci.h       |  6 ++++++
>>>    drivers/pci/pcie/aer.c  | 18 ++++++++++++------
>>>    include/ras/ras_event.h |  9 ++++++---
>>>    3 files changed, 24 insertions(+), 9 deletions(-)
>>>
>>> diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
>>> index b81e99cd4b62..d6296500b004 100644
>>> --- a/drivers/pci/pci.h
>>> +++ b/drivers/pci/pci.h
>>> @@ -588,6 +588,7 @@ static inline bool pci_dev_test_and_set_removed(struct pci_dev *dev)
>>>    struct aer_err_info {
>>>    	struct pci_dev *dev[AER_MAX_MULTI_ERR_DEVICES];
>>>    	int error_dev_num;
>>> +	bool is_cxl;
>> Do you really need this member ? Why not just use pcie_is_cxl() in aer_err_bus()?
> This was added per Dan's request instead of using pcie_is_cxl().[1]
>
> [1] https://lore.kernel.org/linux-cxl/67abe1903a8ed_2d1e2942f@dwillia2-xfh.jf.intel.com.notmuch/
>
> -Terry

It looks like it is added to accommodate some future use cases. May be add some info about it in the aer_err_info struct. Just looking at the code, that member value mirrors pci_dev->is_cxl and where ever you read info->cxl, you can also read the value from pci_dev->is_cxl.
>>>    
>>>    	unsigned int id:16;
>>>    
>>> @@ -604,6 +605,11 @@ struct aer_err_info {
>>>    	struct pcie_tlp_log tlp;	/* TLP Header */
>>>    };
>>>    
>>> +static inline const char *aer_err_bus(struct aer_err_info *info)
>>> +{
>>> +	return info->is_cxl ? "CXL" : "PCIe";
>>> +}
>>> +
>>>    int aer_get_device_error_info(struct pci_dev *dev, struct aer_err_info *info);
>>>    void aer_print_error(struct pci_dev *dev, struct aer_err_info *info);
>>>    
>>> diff --git a/drivers/pci/pcie/aer.c b/drivers/pci/pcie/aer.c
>>> index a1cf8c7ef628..adb4b1123b9b 100644
>>> --- a/drivers/pci/pcie/aer.c
>>> +++ b/drivers/pci/pcie/aer.c
>>> @@ -698,13 +698,14 @@ static void __aer_print_error(struct pci_dev *dev,
>>>    
>>>    void aer_print_error(struct pci_dev *dev, struct aer_err_info *info)
>>>    {
>>> +	const char *bus_type = aer_err_bus(info);
>>>    	int layer, agent;
>>>    	int id = pci_dev_id(dev);
>>>    	const char *level;
>>>    
>>>    	if (!info->status) {
>>> -		pci_err(dev, "PCIe Bus Error: severity=%s, type=Inaccessible, (Unregistered Agent ID)\n",
>>> -			aer_error_severity_string[info->severity]);
>>> +		pci_err(dev, "%s Bus Error: severity=%s, type=Inaccessible, (Unregistered Agent ID)\n",
>>> +			bus_type, aer_error_severity_string[info->severity]);
>>>    		goto out;
>>>    	}
>>>    
>>> @@ -713,8 +714,8 @@ void aer_print_error(struct pci_dev *dev, struct aer_err_info *info)
>>>    
>>>    	level = (info->severity == AER_CORRECTABLE) ? KERN_WARNING : KERN_ERR;
>>>    
>>> -	aer_printk(level, dev, "PCIe Bus Error: severity=%s, type=%s, (%s)\n",
>>> -		   aer_error_severity_string[info->severity],
>>> +	aer_printk(level, dev, "%s Bus Error: severity=%s, type=%s, (%s)\n",
>>> +		   bus_type, aer_error_severity_string[info->severity],
>>>    		   aer_error_layer[layer], aer_agent_string[agent]);
>>>    
>>>    	aer_printk(level, dev, "  device [%04x:%04x] error status/mask=%08x/%08x\n",
>>> @@ -729,7 +730,7 @@ void aer_print_error(struct pci_dev *dev, struct aer_err_info *info)
>>>    	if (info->id && info->error_dev_num > 1 && info->id == id)
>>>    		pci_err(dev, "  Error of this Agent is reported first\n");
>>>    
>>> -	trace_aer_event(dev_name(&dev->dev), (info->status & ~info->mask),
>>> +	trace_aer_event(dev_name(&dev->dev), bus_type, (info->status & ~info->mask),
>>>    			info->severity, info->tlp_header_valid, &info->tlp);
>>>    }
>>>    
>>> @@ -763,6 +764,7 @@ EXPORT_SYMBOL_GPL(cper_severity_to_aer);
>>>    void pci_print_aer(struct pci_dev *dev, int aer_severity,
>>>    		   struct aer_capability_regs *aer)
>>>    {
>>> +	const char *bus_type;
>>>    	int layer, agent, tlp_header_valid = 0;
>>>    	u32 status, mask;
>>>    	struct aer_err_info info;
>>> @@ -784,6 +786,9 @@ void pci_print_aer(struct pci_dev *dev, int aer_severity,
>>>    	info.status = status;
>>>    	info.mask = mask;
>>>    	info.first_error = PCI_ERR_CAP_FEP(aer->cap_control);
>>> +	info.is_cxl = pcie_is_cxl(dev);
>>> +
>>> +	bus_type = aer_err_bus(&info);
>>>    
>>>    	pci_err(dev, "aer_status: 0x%08x, aer_mask: 0x%08x\n", status, mask);
>>>    	__aer_print_error(dev, &info);
>>> @@ -797,7 +802,7 @@ void pci_print_aer(struct pci_dev *dev, int aer_severity,
>>>    	if (tlp_header_valid)
>>>    		pcie_print_tlp_log(dev, &aer->header_log, dev_fmt("  "));
>>>    
>>> -	trace_aer_event(dev_name(&dev->dev), (status & ~mask),
>>> +	trace_aer_event(dev_name(&dev->dev), bus_type, (status & ~mask),
>>>    			aer_severity, tlp_header_valid, &aer->header_log);
>>>    }
>>>    EXPORT_SYMBOL_NS_GPL(pci_print_aer, "CXL");
>>> @@ -1215,6 +1220,7 @@ int aer_get_device_error_info(struct pci_dev *dev, struct aer_err_info *info)
>>>    	/* Must reset in this function */
>>>    	info->status = 0;
>>>    	info->tlp_header_valid = 0;
>>> +	info->is_cxl = pcie_is_cxl(dev);
>>>    
>>>    	/* The device might not support AER */
>>>    	if (!aer)
>>> diff --git a/include/ras/ras_event.h b/include/ras/ras_event.h
>>> index 14c9f943d53f..080829d59c36 100644
>>> --- a/include/ras/ras_event.h
>>> +++ b/include/ras/ras_event.h
>>> @@ -297,15 +297,17 @@ TRACE_EVENT(non_standard_event,
>>>    
>>>    TRACE_EVENT(aer_event,
>>>    	TP_PROTO(const char *dev_name,
>>> +		 const char *bus_type,
>>>    		 const u32 status,
>>>    		 const u8 severity,
>>>    		 const u8 tlp_header_valid,
>>>    		 struct pcie_tlp_log *tlp),
>>>    
>>> -	TP_ARGS(dev_name, status, severity, tlp_header_valid, tlp),
>>> +	TP_ARGS(dev_name, bus_type, status, severity, tlp_header_valid, tlp),
>>>    
>>>    	TP_STRUCT__entry(
>>>    		__string(	dev_name,	dev_name	)
>>> +		__string(	bus_type,	bus_type	)
>>>    		__field(	u32,		status		)
>>>    		__field(	u8,		severity	)
>>>    		__field(	u8, 		tlp_header_valid)
>>> @@ -314,6 +316,7 @@ TRACE_EVENT(aer_event,
>>>    
>>>    	TP_fast_assign(
>>>    		__assign_str(dev_name);
>>> +		__assign_str(bus_type);
>>>    		__entry->status		= status;
>>>    		__entry->severity	= severity;
>>>    		__entry->tlp_header_valid = tlp_header_valid;
>>> @@ -325,8 +328,8 @@ TRACE_EVENT(aer_event,
>>>    		}
>>>    	),
>>>    
>>> -	TP_printk("%s PCIe Bus Error: severity=%s, %s, TLP Header=%s\n",
>>> -		__get_str(dev_name),
>>> +	TP_printk("%s %s Bus Error: severity=%s, %s, TLP Header=%s\n",
>>> +		__get_str(dev_name), __get_str(bus_type),
>>>    		__entry->severity == AER_CORRECTABLE ? "Corrected" :
>>>    			__entry->severity == AER_FATAL ?
>>>    			"Fatal" : "Uncorrected, non-fatal",
>
-- 
Sathyanarayanan Kuppuswamy
Linux Kernel Developer