Re: [PATCH] cxl/port: Unmask AER internal errors for VH endpoints

[Bowman, Terry]

On 10/30/2026 4:59 AM, Richard Cheng wrote:
> CXL protocol errors are reported through PCIe AER internal errors.
> Unmasking the endpoint's CXL RAS register alone leaves the AER internal
> errors masked, thus the notification can't reach the Root Port.
> 
> Unmask AER internal errors during native endpoint RAS setup for VH
> devices. Allow cxl_port to use pci_aer_unmask_internal_errors() through
> its module-restricted export.
> 
> Verified with QEMU mem-data-ecc injection: the Root Port AER interrupt
> fires, the CXL correctable-error trace is emitted, and the endpoint's
> CorrIntErr counter increments.
> 
> Signed-off-by: Richard Cheng <icheng@xxxxxxxxxx>
> ---
>  drivers/cxl/port.c     | 7 +++++++
>  drivers/pci/pcie/aer.c | 3 ++-
>  2 files changed, 9 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/cxl/port.c b/drivers/cxl/port.c
> index c48216e5078f..c94a310061b0 100644
> --- a/drivers/cxl/port.c
> +++ b/drivers/cxl/port.c
> @@ -121,6 +121,13 @@ static int cxl_ras_unmask(struct cxl_port *port)
>  			orig_val, val);
>  	}
>  
> +	/*
> +	 * RCH errors are reported by the RCEC. VH endpoints report CXL
> +	 * protocol errors as PCIe AER internal errors.
> +	 */
> +	if (!is_cxl_restricted(pdev))
> +		pci_aer_unmask_internal_errors(pdev);
> +
>  	return 0;
>  }
>  

Hi Richard,

The unmasking needs to cover the RCD case as well. The RCD AER is used to mask reporting. 
The is_cxl_restricted() gate should be removed so the pci_aer_unmask_internal_errors() 
is called for both the VH and RCD cases.

I confirmed Sashiko's finding that the unmasking will never execute, thanks to this early
return:
        if (!dev_is_pci(port->uport_dev))    <<== Fails here
                return 0;
        pdev = to_pci_dev(port->uport_dev);

For an endpoint port, port->uport_dev is the cxl_memdev, not a PCI device. So dev_is_pci() 
is false and we return early. The PCI device is `port->uport_dev->parent`.

Note, I used base v7.3-rc7. I couldn't find f0c48323b040.

- Terry

> diff --git a/drivers/pci/pcie/aer.c b/drivers/pci/pcie/aer.c
> index db4f607f889c..94eca22422b7 100644
> --- a/drivers/pci/pcie/aer.c
> +++ b/drivers/pci/pcie/aer.c
> @@ -1287,7 +1287,8 @@ void pci_aer_unmask_internal_errors(struct pci_dev *dev)
>   * Internal errors are too device-specific to enable generally, however for CXL
>   * their behavior is standardized for conveying CXL protocol errors.
>   */
> -EXPORT_SYMBOL_FOR_MODULES(pci_aer_unmask_internal_errors, "cxl_core");
> +EXPORT_SYMBOL_FOR_MODULES(pci_aer_unmask_internal_errors,
> +			  "cxl_core,cxl_port");
>  
>  #ifdef CONFIG_CXL_RAS
>  bool is_aer_internal_error(struct aer_err_info *info)
> 
> base-commit: f0c48323b0402349530abc60ea908b5f5f40c395