[PATCH v8 02/20] PCI/DPC: Log Error Source ID only when valid

Bjorn Helgaas
2025-05-22T23:23:48Z

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.

Fixes: 26e515713342 ("PCI: Add Downstream Port Containment driver")
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Tested-by: Krzysztof Wilczyński <kwilczynski@kernel.org>
Reviewed-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://patch.msgid.link/20250520215047.1350603-3-helgaas@kernel.org
---
drivers/pci/pcie/dpc.c | 64 ++++++++++++++++++++++++------------------
1 file changed, 36 insertions(+), 28 deletions(-)

diff --git a/drivers/pci/pcie/dpc.c b/drivers/pci/pcie/dpc.c
index 3daaf61c79c9..9d85f1b3b761 100644
--- a/drivers/pci/pcie/dpc.c
+++ b/drivers/pci/pcie/dpc.c
@@ -261,37 +261,45 @@ void dpc_process_error(struct pci_dev *pdev)
struct aer_err_info info = {};

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");

- /* show RP PIO error detail information */
- if (pdev->dpc_rp_extensions &&
- reason == PCI_EXP_DPC_STATUS_TRIGGER_RSN_IN_EXT &&
- ext_reason == PCI_EXP_DPC_STATUS_TRIGGER_RSN_RP_PIO)
- dpc_process_rp_pio_error(pdev);
- else if (reason == PCI_EXP_DPC_STATUS_TRIGGER_RSN_UNCOR &&
- dpc_get_aer_uncorrect_severity(pdev, &info) &&
- aer_get_device_error_info(pdev, &info)) {
- aer_print_error(pdev, &info);
- pci_aer_clear_nonfatal_status(pdev);
- pci_aer_clear_fatal_status(pdev);
+ switch (reason) {
+ case PCI_EXP_DPC_STATUS_TRIGGER_RSN_UNCOR:
+ pci_warn(pdev, "containment event, status:%#06x: unmasked uncorrectable error detected\n",
+ status);
+ if (dpc_get_aer_uncorrect_severity(pdev, &info) &&
+ aer_get_device_error_info(pdev, &info)) {
+ aer_print_error(pdev, &info);
+ pci_aer_clear_nonfatal_status(pdev);
+ pci_aer_clear_fatal_status(pdev);
+ }
+ 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,
+ (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));
+ break;
+ 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");
+ /* show RP PIO error detail information */
+ if (ext_reason == PCI_EXP_DPC_STATUS_TRIGGER_RSN_RP_PIO &&
+ pdev->dpc_rp_extensions)
+ dpc_process_rp_pio_error(pdev);
+ break;
}
}

--
2.43.0