Re: [PATCH v4 15/15] PCI/AER: Enable internal errors for CXL Upstream and Downstream Switch Ports

Alejandro Lucero Palau
2024-12-12T10:44:09Z

On 12/12/24 09:44, Alejandro Lucero Palau wrote:
>
> On 12/11/24 23:40, Terry Bowman wrote:
>> The AER service driver enables PCIe Uncorrectable Internal Errors
>> (UIE) and
>> Correctable Internal errors (CIE) for CXL Root Ports and CXL RCEC's. The
>> UIE and CIE are used in reporting CXL Protocol Errors. The same UIE/CIE
>> enablement is needed for CXL PCIe Upstream and Downstream Ports
>> inorder to
>> notify the associated Root Port and OS.[1]
>>
>> Export the AER service driver's pci_aer_unmask_internal_errors()
>> function
>> to CXL namespace.
>>
>> Remove the function's dependency on the CONFIG_PCIEAER_CXL kernel config
>> because it is now an exported function.
>>
>> Call pci_aer_unmask_internal_errors() during RAS initialization in:
>> cxl_uport_init_ras_reporting() and cxl_dport_init_ras_reporting().
>>
>> [1] PCIe Base Spec r6.2-1.0, 6.2.3.2.2 Masking Individual Errors
>>
>> Signed-off-by: Terry Bowman <terry.bowman@amd.com>
>> ---
>>   drivers/cxl/core/pci.c | 2 ++
>>   drivers/pci/pcie/aer.c | 5 +++--
>>   include/linux/aer.h    | 1 +
>>   3 files changed, 6 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/cxl/core/pci.c b/drivers/cxl/core/pci.c
>> index 9734a4c55b29..740ac5d8809f 100644
>> --- a/drivers/cxl/core/pci.c
>> +++ b/drivers/cxl/core/pci.c
>> @@ -886,6 +886,7 @@ void cxl_uport_init_ras_reporting(struct cxl_port
>> *port)
>>         cxl_assign_port_error_handlers(pdev);
>>       devm_add_action_or_reset(port->uport_dev,
>> cxl_clear_port_error_handlers, pdev);
>> +    pci_aer_unmask_internal_errors(pdev);
>>   }
>>   EXPORT_SYMBOL_NS_GPL(cxl_uport_init_ras_reporting, CXL);
>>   @@ -920,6 +921,7 @@ void cxl_dport_init_ras_reporting(struct
>> cxl_dport *dport)
>>         cxl_assign_port_error_handlers(pdev);
>>       devm_add_action_or_reset(dport_dev,
>> cxl_clear_port_error_handlers, pdev);
>> +    pci_aer_unmask_internal_errors(pdev);
>>   }
>>   EXPORT_SYMBOL_NS_GPL(cxl_dport_init_ras_reporting, CXL);
>>   diff --git a/drivers/pci/pcie/aer.c b/drivers/pci/pcie/aer.c
>> index 861521872318..0fa1b1ed48c9 100644
>> --- a/drivers/pci/pcie/aer.c
>> +++ b/drivers/pci/pcie/aer.c
>> @@ -949,7 +949,6 @@ static bool is_internal_error(struct aer_err_info
>> *info)
>>       return info->status & PCI_ERR_UNC_INTN;
>>   }
>>   -#ifdef CONFIG_PCIEAER_CXL
>
>
> This ifdef move puzzles me. I would expect to use it when the next
> function is invoked instead of moving it here.
>
> It seems weird to have such a config but code using those related
> functions not aware of it.
>
>
>>   /**
>>    * pci_aer_unmask_internal_errors - unmask internal errors
>>    * @dev: pointer to the pcie_dev data structure
>> @@ -960,7 +959,7 @@ static bool is_internal_error(struct aer_err_info
>> *info)
>>    * Note: AER must be enabled and supported by the device which must be
>>    * checked in advance, e.g. with pcie_aer_is_native().
>>    */
>> -static void pci_aer_unmask_internal_errors(struct pci_dev *dev)
>> +void pci_aer_unmask_internal_errors(struct pci_dev *dev)
>>   {
>>       int aer = dev->aer_cap;
>>       u32 mask;
>> @@ -973,7 +972,9 @@ static void pci_aer_unmask_internal_errors(struct
>> pci_dev *dev)
>>       mask &= ~PCI_ERR_COR_INTERNAL;
>>       pci_write_config_dword(dev, aer + PCI_ERR_COR_MASK, mask);
>>   }
>> +EXPORT_SYMBOL_NS_GPL(pci_aer_unmask_internal_errors, CXL);

Forgot to mention all these exports are changing in 6.13 with the second
macro param being now an string, so just

EXPORT_SYMBOL_NS_GPL(pci_aer_unmask_internal_errors, "CXL");

Not affected in the codebase linked to this patchset, but I hope it
helps you when getting weird errors with a newer kernel.

>>   +#ifdef CONFIG_PCIEAER_CXL
>>   static bool is_cxl_mem_dev(struct pci_dev *dev)
>>   {
>>       /*
>> diff --git a/include/linux/aer.h b/include/linux/aer.h
>> index 4b97f38f3fcf..093293f9f12b 100644
>> --- a/include/linux/aer.h
>> +++ b/include/linux/aer.h
>> @@ -55,5 +55,6 @@ void pci_print_aer(struct pci_dev *dev, int
>> aer_severity,
>>   int cper_severity_to_aer(int cper_severity);
>>   void aer_recover_queue(int domain, unsigned int bus, unsigned int
>> devfn,
>>                  int severity, struct aer_capability_regs *aer_regs);
>> +void pci_aer_unmask_internal_errors(struct pci_dev *dev);
>>   #endif //_AER_H_
>