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Message-ID: <fe1daf3b-162e-4132-8cdc-c89305391090@linux.intel.com>
Date: Mon, 20 Oct 2025 11:38:06 -0700
From: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@...ux.intel.com>
To: Shuai Xue <xueshuai@...ux.alibaba.com>, linux-pci@...r.kernel.org,
linux-kernel@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org,
bhelgaas@...gle.com, kbusch@...nel.org
Cc: mahesh@...ux.ibm.com, oohall@...il.com, Jonathan.Cameron@...wei.com,
terry.bowman@....com, tianruidong@...ux.alibaba.com, lukas@...ner.de
Subject: Re: [PATCH v6 3/5] PCI/AER: Report fatal errors of RCiEP and EP if
link recoverd
On 10/14/25 19:41, Shuai Xue wrote:
> The AER driver has historically avoided reading the configuration space of
> an endpoint or RCiEP that reported a fatal error, considering the link to
> that device unreliable. Consequently, when a fatal error occurs, the AER
> and DPC drivers do not report specific error types, resulting in logs like:
>
> pcieport 0015:00:00.0: EDR: EDR event received
> pcieport 0015:00:00.0: EDR: Reported EDR dev: 0015:00:00.0
> pcieport 0015:00:00.0: DPC: containment event, status:0x200d, ERR_FATAL received from 0015:01:00.0
> pcieport 0015:00:00.0: AER: broadcast error_detected message
> pcieport 0015:00:00.0: AER: broadcast mmio_enabled message
> pcieport 0015:00:00.0: AER: broadcast resume message
> pcieport 0015:00:00.0: pciehp: Slot(21): Link Down/Up ignored
> pcieport 0015:00:00.0: AER: device recovery successful
> pcieport 0015:00:00.0: EDR: DPC port successfully recovered
> pcieport 0015:00:00.0: EDR: Status for 0015:00:00.0: 0x80
>
> AER status registers are sticky and Write-1-to-clear. If the link recovered
> after hot reset, we can still safely access AER status and TLP header of the
> error device. In such case, report fatal errors which helps to figure out the
> error root case.
>
> After this patch, the logs like:
>
> pcieport 0015:00:00.0: EDR: EDR event received
> pcieport 0015:00:00.0: EDR: Reported EDR dev: 0015:00:00.0
> pcieport 0015:00:00.0: DPC: containment event, status:0x200d, ERR_FATAL received from 0015:01:00.0
> pcieport 0015:00:00.0: AER: broadcast error_detected message
> vfio-pci 0015:01:00.0: PCIe Bus Error: severity=Uncorrectable (Fatal), type=Transaction Layer, (Receiver ID)
> pcieport 0015:00:00.0: pciehp: Slot(21): Link Down/Up ignored
It would be more clear if you follow the same order of the log as before section
and highlight the new logs that are getting added.
> vfio-pci 0015:01:00.0: device [144d:a80a] error status/mask=00001000/00400000
> vfio-pci 0015:01:00.0: [12] TLP (First)
> vfio-pci 0015:01:00.0: AER: TLP Header: 0x4a004010 0x00000040 0x01000000 0xffffffff
> pcieport 0015:00:00.0: AER: broadcast mmio_enabled message
> pcieport 0015:00:00.0: AER: broadcast resume message
> pcieport 0015:00:00.0: AER: device recovery successful
> pcieport 0015:00:00.0: EDR: DPC port successfully recovered
> pcieport 0015:00:00.0: EDR: Status for 0015:00:00.0: 0x80
>
> Signed-off-by: Shuai Xue <xueshuai@...ux.alibaba.com>
> ---
> drivers/pci/pci.h | 4 +++-
> drivers/pci/pcie/aer.c | 18 +++++++++++-------
> drivers/pci/pcie/dpc.c | 2 +-
> drivers/pci/pcie/err.c | 11 +++++++++++
> 4 files changed, 26 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
> index 6b0c55bed15b..3eccef2d25a3 100644
> --- a/drivers/pci/pci.h
> +++ b/drivers/pci/pci.h
> @@ -739,8 +739,10 @@ struct aer_err_info {
> struct pcie_tlp_log tlp; /* TLP Header */
> };
>
> -int aer_get_device_error_info(struct aer_err_info *info, int i);
> +int aer_get_device_error_info(struct aer_err_info *info, int i,
> + bool link_healthy);
> void aer_print_error(struct aer_err_info *info, int i);
> +int aer_add_error_device(struct aer_err_info *e_info, struct pci_dev *dev);
>
> int pcie_read_tlp_log(struct pci_dev *dev, int where, int where2,
> unsigned int tlp_len, bool flit,
> diff --git a/drivers/pci/pcie/aer.c b/drivers/pci/pcie/aer.c
> index 0b5ed4722ac3..aaea9902cbb7 100644
> --- a/drivers/pci/pcie/aer.c
> +++ b/drivers/pci/pcie/aer.c
> @@ -978,7 +978,7 @@ EXPORT_SYMBOL_NS_GPL(pci_print_aer, "CXL");
> * @e_info: pointer to error info
> * @dev: pointer to pci_dev to be added
> */
> -static int add_error_device(struct aer_err_info *e_info, struct pci_dev *dev)
> +int aer_add_error_device(struct aer_err_info *e_info, struct pci_dev *dev)
I don't think you need this rename.
> {
> int i = e_info->error_dev_num;
>
> @@ -1068,7 +1068,7 @@ static int find_device_iter(struct pci_dev *dev, void *data)
>
> if (is_error_source(dev, e_info)) {
> /* List this device */
> - if (add_error_device(e_info, dev)) {
> + if (aer_add_error_device(e_info, dev)) {
> /* We cannot handle more... Stop iteration */
> pci_err(dev, "Exceeded max supported (%d) devices with errors logged\n",
> AER_MAX_MULTI_ERR_DEVICES);
> @@ -1382,12 +1382,14 @@ EXPORT_SYMBOL_GPL(aer_recover_queue);
> * aer_get_device_error_info - read error status from dev and store it to info
> * @info: pointer to structure to store the error record
> * @i: index into info->dev[]
> + * @link_healthy: link is healthy or not
> *
> * Return: 1 on success, 0 on error.
> *
> * Note that @info is reused among all error devices. Clear fields properly.
> */
> -int aer_get_device_error_info(struct aer_err_info *info, int i)
> +int aer_get_device_error_info(struct aer_err_info *info, int i,
> + bool link_healthy)
> {
> struct pci_dev *dev;
> int type, aer;
> @@ -1415,10 +1417,12 @@ int aer_get_device_error_info(struct aer_err_info *info, int i)
> &info->mask);
> if (!(info->status & ~info->mask))
> return 0;
> + info->level = KERN_WARNING;
I recommend setting this when initializing the info->level at the caller end (to match
other callers)
> } else if (type == PCI_EXP_TYPE_ROOT_PORT ||
> type == PCI_EXP_TYPE_RC_EC ||
> type == PCI_EXP_TYPE_DOWNSTREAM ||
> - info->severity == AER_NONFATAL) {
> + info->severity == AER_NONFATAL ||
> + (info->severity == AER_FATAL && link_healthy)) {
>
> /* Link is still healthy for IO reads */
> pci_read_config_dword(dev, aer + PCI_ERR_UNCOR_STATUS,
> @@ -1427,7 +1431,7 @@ int aer_get_device_error_info(struct aer_err_info *info, int i)
> &info->mask);
> if (!(info->status & ~info->mask))
> return 0;
> -
> + info->level = KERN_ERR;
> /* Get First Error Pointer */
> pci_read_config_dword(dev, aer + PCI_ERR_CAP, &aercc);
> info->first_error = PCI_ERR_CAP_FEP(aercc);
> @@ -1451,11 +1455,11 @@ static inline void aer_process_err_devices(struct aer_err_info *e_info)
>
> /* Report all before handling them, to not lose records by reset etc. */
> for (i = 0; i < e_info->error_dev_num && e_info->dev[i]; i++) {
> - if (aer_get_device_error_info(e_info, i))
> + if (aer_get_device_error_info(e_info, i, false))
> aer_print_error(e_info, i);
> }
> for (i = 0; i < e_info->error_dev_num && e_info->dev[i]; i++) {
> - if (aer_get_device_error_info(e_info, i))
> + if (aer_get_device_error_info(e_info, i, false))
> handle_error_source(e_info->dev[i], e_info);
> }
> }
> diff --git a/drivers/pci/pcie/dpc.c b/drivers/pci/pcie/dpc.c
> index f6069f621683..21c4e8371279 100644
> --- a/drivers/pci/pcie/dpc.c
> +++ b/drivers/pci/pcie/dpc.c
> @@ -284,7 +284,7 @@ struct pci_dev *dpc_process_error(struct pci_dev *pdev)
> 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(&info, 0)) {
> + aer_get_device_error_info(&info, 0, false)) {
> aer_print_error(&info, 0);
> pci_aer_clear_nonfatal_status(pdev);
> pci_aer_clear_fatal_status(pdev);
> diff --git a/drivers/pci/pcie/err.c b/drivers/pci/pcie/err.c
> index bebe4bc111d7..4e65eac809d1 100644
> --- a/drivers/pci/pcie/err.c
> +++ b/drivers/pci/pcie/err.c
> @@ -215,6 +215,7 @@ pci_ers_result_t pcie_do_recovery(struct pci_dev *dev,
> struct pci_dev *bridge;
> pci_ers_result_t status = PCI_ERS_RESULT_CAN_RECOVER;
> struct pci_host_bridge *host = pci_find_host_bridge(dev->bus);
> + struct aer_err_info info;
>
> /*
> * If the error was detected by a Root Port, Downstream Port, RCEC,
> @@ -253,6 +254,16 @@ pci_ers_result_t pcie_do_recovery(struct pci_dev *dev,
> pci_warn(bridge, "subordinate device reset failed\n");
> goto failed;
> }
> +
> + /* Link recovered, report fatal errors of RCiEP or EP */
> + if (state == pci_channel_io_frozen &&
> + (type == PCI_EXP_TYPE_ENDPOINT || type == PCI_EXP_TYPE_RC_END)) {
> + aer_add_error_device(&info, dev);
> + info.severity = AER_FATAL;
info.level = KERN_ERR ?
> + if (aer_get_device_error_info(&info, 0, true))
> + aer_print_error(&info, 0);
> + pci_dev_put(dev);
Like Lukas mentioned, it needs a comment about why you need this.
> + }
> }
>
> if (status == PCI_ERS_RESULT_NEED_RESET) {
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