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

Sathyanarayanan Kuppuswamy
2025-05-19T23:16:07Z

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