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

[Richard Cheng]

On Fri, Oct 30, 2026 at 01:28:14PM +0800, Bowman, Terry wrote:
> 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`.
>

Hi Terry,

Thanks for the headup, and I've also send a patch to fix this issue [1].

And seems like your patch mentioned by Li Ming is already covering
this bug ? if that's the case we can focus on yours, if not I would love
to make the fix in.

Best regards,
Richard Cheng.

[1]: https://lore.kernel.org/linux-cxl/20261103063409.18275-1-icheng@xxxxxxxxxx/
 
> 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
>