Re: [PATCH v6 02/16] PCI/DPC: Log Error Source ID only when valid

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

On 5/19/25 2:35 PM, Bjorn Helgaas wrote:
> From: Bjorn Helgaas <bhelgaas@google.com>
>
> DPC Error Source ID is only valid when the DPC Trigger Reason indicates
> that DPC was triggered due to reception of an ERR_NONFATAL or ERR_FATAL
> Message (PCIe r6.0, sec 7.9.14.5).
>
> When DPC was triggered by ERR_NONFATAL (PCI_EXP_DPC_STATUS_TRIGGER_RSN_NFE)
> or ERR_FATAL (PCI_EXP_DPC_STATUS_TRIGGER_RSN_FE) from a downstream device,
> log the Error Source ID (decoded into domain/bus/device/function).  Don't
> print the source otherwise, since it's not valid.
>
> For DPC trigger due to reception of ERR_NONFATAL or ERR_FATAL, the dmesg
> logging changes:
>
>    - pci 0000:00:01.0: DPC: containment event, status:0x000d source:0x0200
>    - pci 0000:00:01.0: DPC: ERR_FATAL detected
>    + pci 0000:00:01.0: DPC: containment event, status:0x000d, ERR_FATAL received from 0000:02:00.0
>
> and when DPC triggered for other reasons, where DPC Error Source ID is
> undefined, e.g., unmasked uncorrectable error:
>
>    - pci 0000:00:01.0: DPC: containment event, status:0x0009 source:0x0200
>    - pci 0000:00:01.0: DPC: unmasked uncorrectable error detected
>    + pci 0000:00:01.0: DPC: containment event, status:0x0009: unmasked uncorrectable error detected
>
> Previously the "containment event" message was at KERN_INFO and the
> "%s detected" message was at KERN_WARNING.  Now the single message is at
> KERN_WARNING.

Since we are handling Uncorrectable errors, why not use pci_err?

>
> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
> ---

Reviewed-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>

>   drivers/pci/pcie/dpc.c | 45 ++++++++++++++++++++++++++----------------
>   1 file changed, 28 insertions(+), 17 deletions(-)
>
> diff --git a/drivers/pci/pcie/dpc.c b/drivers/pci/pcie/dpc.c
> index fe7719238456..315bf2bfd570 100644
> --- a/drivers/pci/pcie/dpc.c
> +++ b/drivers/pci/pcie/dpc.c
> @@ -261,25 +261,36 @@ void dpc_process_error(struct pci_dev *pdev)
>   	struct aer_err_info info = { 0 };
>   
>   	pci_read_config_word(pdev, cap + PCI_EXP_DPC_STATUS, &status);
> -	pci_read_config_word(pdev, cap + PCI_EXP_DPC_SOURCE_ID, &source);
> -
> -	pci_info(pdev, "containment event, status:%#06x source:%#06x\n",
> -		 status, source);
>   
>   	reason = status & PCI_EXP_DPC_STATUS_TRIGGER_RSN;
> -	ext_reason = status & PCI_EXP_DPC_STATUS_TRIGGER_RSN_EXT;
> -	pci_warn(pdev, "%s detected\n",
> -		 (reason == PCI_EXP_DPC_STATUS_TRIGGER_RSN_UNCOR) ?
> -		 "unmasked uncorrectable error" :
> -		 (reason == PCI_EXP_DPC_STATUS_TRIGGER_RSN_NFE) ?
> -		 "ERR_NONFATAL" :
> -		 (reason == PCI_EXP_DPC_STATUS_TRIGGER_RSN_FE) ?
> -		 "ERR_FATAL" :
> -		 (ext_reason == PCI_EXP_DPC_STATUS_TRIGGER_RSN_RP_PIO) ?
> -		 "RP PIO error" :
> -		 (ext_reason == PCI_EXP_DPC_STATUS_TRIGGER_RSN_SW_TRIGGER) ?
> -		 "software trigger" :
> -		 "reserved error");
> +
> +	switch (reason) {
> +	case PCI_EXP_DPC_STATUS_TRIGGER_RSN_UNCOR:
> +		pci_warn(pdev, "containment event, status:%#06x: unmasked uncorrectable error detected\n",
> +			 status);
> +		break;
> +	case PCI_EXP_DPC_STATUS_TRIGGER_RSN_NFE:
> +	case PCI_EXP_DPC_STATUS_TRIGGER_RSN_FE:
> +		pci_read_config_word(pdev, cap + PCI_EXP_DPC_SOURCE_ID,
> +				     &source);
> +		pci_warn(pdev, "containment event, status:%#06x, %s received from %04x:%02x:%02x.%d\n",
> +			 status,

I see the BDF extraction and format code in many places in the PCI drivers. May be a
common macro will make it more readable.

> +			 (reason == PCI_EXP_DPC_STATUS_TRIGGER_RSN_FE) ?
> +				"ERR_FATAL" : "ERR_NONFATAL",
> +			 pci_domain_nr(pdev->bus), PCI_BUS_NUM(source),
> +			 PCI_SLOT(source), PCI_FUNC(source));
> +		return;
> +	case PCI_EXP_DPC_STATUS_TRIGGER_RSN_IN_EXT:
> +		ext_reason = status & PCI_EXP_DPC_STATUS_TRIGGER_RSN_EXT;
> +		pci_warn(pdev, "containment event, status:%#06x: %s detected\n",
> +			 status,
> +			 (ext_reason == PCI_EXP_DPC_STATUS_TRIGGER_RSN_RP_PIO) ?
> +			 "RP PIO error" :
> +			 (ext_reason == PCI_EXP_DPC_STATUS_TRIGGER_RSN_SW_TRIGGER) ?
> +			 "software trigger" :
> +			 "reserved error");
> +		break;
> +	}
>   
>   	/* show RP PIO error detail information */
>   	if (pdev->dpc_rp_extensions &&

-- 
Sathyanarayanan Kuppuswamy
Linux Kernel Developer