Subject: Re: [PATCH v7 3/5] PCI/AER: Report fatal errors of RCiEP and EP if link recoverd

From: Jonathan Cameron <[email-masked]>
Date: Tue, 27 Jan 2026 10:36:43 +0000

On Sat, 24 Jan 2026 15:45:55 +0800
Shuai Xue <[email-masked]> 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: AER: Errors reported prior to reset
> + vfio-pci 0015:01:00.0: PCIe Bus Error: severity=Uncorrectable (Fatal), type=Transaction Layer, (Receiver ID)
> + 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: 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
> 
> Signed-off-by: Shuai Xue <[email-masked]>
Hi Shuai,

With the structure zeroed below (just to make this easier to review, not because
there is a bug as far as I can see)
Reviewed-by: Jonathan Cameron <[email-masked]>

> diff --git a/drivers/pci/pcie/aer.c b/drivers/pci/pcie/aer.c
> index e0bcaa896803..4c0a2bbe9197 100644
> --- a/drivers/pci/pcie/aer.c
> +++ b/drivers/pci/pcie/aer.c

> @@ -1447,17 +1450,38 @@ int aer_get_device_error_info(struct aer_err_info *info, int i)
>  	return 1;
>  }
>  
> +void aer_report_frozen_error(struct pci_dev *dev)
> +{
> +	struct aer_err_info info;
> +	int type = pci_pcie_type(dev);
> +
> +	if (type != PCI_EXP_TYPE_ENDPOINT && type != PCI_EXP_TYPE_RC_END)
> +		return;
> +

struct aer_err_info has a bunch of fields. I'd just make sure it's zeroed
to avoid us having to check that they are all filled in. = {};
or do it with the initial values being assigned.

	info = (struct aer_err_info) {
		.err_dev_num = 0,
		.severity = AER_FATAL,
		.level = KERN_ERR,
	};
	add_error_device(&info, dev);

> +	info.error_dev_num = 0;
> +	info.severity = AER_FATAL;
> +	info.level = KERN_ERR;
> +	add_error_device(&info, dev);
> +
> +	if (aer_get_device_error_info(&info, 0, true)) {
> +		pci_err(dev, "Errors reported prior to reset\n");
> +		aer_print_error(&info, 0);
> +	}
> +
> +	pci_dev_put(dev); /* pairs with pci_dev_get() in add_error_device() */
> +}