Re: [RFC PATCH 8/9] PCI/AER: Export pci_aer_unmask_internal_errors()

Terry Bowman
2024-06-24T16:22:20Z

Hi Jonathan,

I added a response inline below.

On 6/20/24 08:11, Jonathan Cameron wrote:
> On Mon, 17 Jun 2024 15:04:10 -0500
> Terry Bowman <terry.bowman@amd.com> wrote:
>
>> AER correctable internal errors (CIE) and AER uncorrectable internal
>> errors (UIE) are disabled through the AER mask register by default.[1]
>>
>> CXL PCIe ports use the CIE/UIE to report RAS errors and as a result
>> need CIE/UIE enabled.[2]
>>
>> Change pci_aer_unmask_internal_errors() function to be exported for
>> the CXL driver and other drivers to use.
>
> I've perhaps forgotten the end conclusion, but I thought there was
> a request to just try enabling this in general and mask it out only
> for known broken devices?
>
> Admittedly that's a more daring path, so maybe I hallucinated it!
>

I remember there was discussion. A quick search for PCI_ERR_COR_INTERNAL and
PCI_ERR_UNC_INTERNAL doesn't find any default enablement.

Regards,
Terry

>>
>> [1] PCI6.0 - 7.8.4.3 Uncorrectable
>> [2] CXL3.1 - 12.2.2 CXL Root Ports, Downstream Switch Ports, and Upstream
>> Switch Ports
>>
>> Signed-off-by: Terry Bowman <terry.bowman@amd.com>
>> Cc: Bjorn Helgaas <bhelgaas@google.com>
>> Cc: linux-pci@vger.kernel.org
>> ---
>> drivers/pci/pcie/aer.c | 3 ++-
>> include/linux/aer.h | 6 ++++++
>> 2 files changed, 8 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/pci/pcie/aer.c b/drivers/pci/pcie/aer.c
>> index 4dc03cb9aff0..d7a1982f0c50 100644
>> --- a/drivers/pci/pcie/aer.c
>> +++ b/drivers/pci/pcie/aer.c
>> @@ -951,7 +951,7 @@ static bool find_source_device(struct pci_dev *parent,
>> * 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;
>> @@ -964,6 +964,7 @@ 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_GPL(pci_aer_unmask_internal_errors);
>>
>> static bool is_cxl_mem_dev(struct pci_dev *dev)
>> {
>> diff --git a/include/linux/aer.h b/include/linux/aer.h
>> index 4b97f38f3fcf..a4fd25ea0280 100644
>> --- a/include/linux/aer.h
>> +++ b/include/linux/aer.h
>> @@ -50,6 +50,12 @@ static inline int pci_aer_clear_nonfatal_status(struct pci_dev *dev)
>> static inline int pcie_aer_is_native(struct pci_dev *dev) { return 0; }
>> #endif
>>
>> +#ifdef CONFIG_PCIEAER_CXL
>> +void pci_aer_unmask_internal_errors(struct pci_dev *dev);
>> +#else
>> +static inline void pci_aer_unmask_internal_errors(struct pci_dev *dev) { }
>> +#endif
>> +
>> void pci_print_aer(struct pci_dev *dev, int aer_severity,
>> struct aer_capability_regs *aer);
>> int cper_severity_to_aer(int cper_severity);
>