Re: [PATCH v5 16/16] PCI/AER: Enable internal errors for CXL Upstream and Downstream Switch Ports

[Ira Weiny <ira.weiny@intel.com>]

Bowman, Terry wrote:
> 
> 
> 
> On 1/14/2025 5:26 PM, Ira Weiny wrote:
> > Terry Bowman wrote:
> >> The AER service driver enables PCIe Uncorrectable Internal Errors (UIE) and
> >> Correctable Internal errors (CIE) for CXL Root Ports. The UIE and CIE are
> >> used in reporting CXL Protocol Errors. The same UIE/CIE enablement is
> >> needed for CXL Upstream Switch Ports and CXL Downstream Switch Ports
> >> inorder to notify the associated Root Port and OS.[1]
> >>
> >> Export the AER service driver's pci_aer_unmask_internal_errors() function
> >> to CXL namespace.
> >>
> >> Remove the function's dependency on the CONFIG_PCIEAER_CXL kernel config
> >> because it is now an exported function.
> > This seems wrong to me.  As of this patch CXL_PCI requires PCIEAER_CXL for
> > the AER code to handle the errors which were just enabled.
> >
> > To keep PCIEAER_CXL optional pci_aer_unmask_internal_errors() should be
> > stubbed out in aer.h if !CONFIG_PCIEAER_CXL.
> >
> > Ira
> 
> Bjorn (I believe in v1 or v2) directed me to remove
> pci_aer_unmask_internal_errors() dependency on PCIEAER_CXL because it is
> now exported. He wants the behavior for other users (and subsystems) to
> be consistent with/without the PCIEAER_CXL setting.
> 

I see...  If PCIEAER_CXL is not enabled why even set the cxl error
handlers and enable these?

I guess this is just adding some code which eventually calls
handles_cxl_errors() which returns false in the !PCIEAER_CXL case?

Ira

> Regards,
> Terry
> 
> >> Call pci_aer_unmask_internal_errors() during RAS initialization in:
> >> cxl_uport_init_ras_reporting() and cxl_dport_init_ras_reporting().
> >>
> >> [1] PCIe Base Spec r6.2-1.0, 6.2.3.2.2 Masking Individual Errors
> >>
> >> Signed-off-by: Terry Bowman <terry.bowman@amd.com>
> >> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
> >> ---
> >>  drivers/cxl/core/pci.c | 2 ++
> >>  drivers/pci/pcie/aer.c | 5 +++--
> >>  include/linux/aer.h    | 1 +
> >>  3 files changed, 6 insertions(+), 2 deletions(-)
> >>
> >> diff --git a/drivers/cxl/core/pci.c b/drivers/cxl/core/pci.c
> >> index 9c162120f0fe..c62329cd9a87 100644
> >> --- a/drivers/cxl/core/pci.c
> >> +++ b/drivers/cxl/core/pci.c
> >> @@ -895,6 +895,7 @@ void cxl_uport_init_ras_reporting(struct cxl_port *port)
> >>  
> >>  	cxl_assign_port_error_handlers(pdev);
> >>  	devm_add_action_or_reset(&port->dev, cxl_clear_port_error_handlers, pdev);
> >> +	pci_aer_unmask_internal_errors(pdev);
> >>  }
> >>  EXPORT_SYMBOL_NS_GPL(cxl_uport_init_ras_reporting, "CXL");
> >>  
> >> @@ -935,6 +936,7 @@ void cxl_dport_init_ras_reporting(struct cxl_dport *dport)
> >>  	}
> >>  	cxl_assign_port_error_handlers(pdev);
> >>  	devm_add_action_or_reset(&port->dev, cxl_clear_port_error_handlers, pdev);
> >> +	pci_aer_unmask_internal_errors(pdev);
> >>  	put_device(&port->dev);
> >>  }
> >>  EXPORT_SYMBOL_NS_GPL(cxl_dport_init_ras_reporting, "CXL");
> >> diff --git a/drivers/pci/pcie/aer.c b/drivers/pci/pcie/aer.c
> >> index 68e957459008..e6aaa3bd84f0 100644
> >> --- a/drivers/pci/pcie/aer.c
> >> +++ b/drivers/pci/pcie/aer.c
> >> @@ -950,7 +950,6 @@ static bool is_internal_error(struct aer_err_info *info)
> >>  	return info->status & PCI_ERR_UNC_INTN;
> >>  }
> >>  
> >> -#ifdef CONFIG_PCIEAER_CXL
> >>  /**
> >>   * pci_aer_unmask_internal_errors - unmask internal errors
> >>   * @dev: pointer to the pcie_dev data structure
> >> @@ -961,7 +960,7 @@ static bool is_internal_error(struct aer_err_info *info)
> >>   * Note: AER must be enabled and supported by the device which must be
> >>   * checked in advance, e.g. with pcie_aer_is_native().
> >>   */
> >> -static void pci_aer_unmask_internal_errors(struct pci_dev *dev)
> >> +void pci_aer_unmask_internal_errors(struct pci_dev *dev)
> >>  {
> >>  	int aer = dev->aer_cap;
> >>  	u32 mask;
> >> @@ -974,7 +973,9 @@ static void pci_aer_unmask_internal_errors(struct pci_dev *dev)
> >>  	mask &= ~PCI_ERR_COR_INTERNAL;
> >>  	pci_write_config_dword(dev, aer + PCI_ERR_COR_MASK, mask);
> >>  }
> >> +EXPORT_SYMBOL_NS_GPL(pci_aer_unmask_internal_errors, "CXL");
> >>  
> >> +#ifdef CONFIG_PCIEAER_CXL
> >>  static bool is_cxl_mem_dev(struct pci_dev *dev)
> >>  {
> >>  	/*
> >> diff --git a/include/linux/aer.h b/include/linux/aer.h
> >> index 4b97f38f3fcf..093293f9f12b 100644
> >> --- a/include/linux/aer.h
> >> +++ b/include/linux/aer.h
> >> @@ -55,5 +55,6 @@ void pci_print_aer(struct pci_dev *dev, int aer_severity,
> >>  int cper_severity_to_aer(int cper_severity);
> >>  void aer_recover_queue(int domain, unsigned int bus, unsigned int devfn,
> >>  		       int severity, struct aer_capability_regs *aer_regs);
> >> +void pci_aer_unmask_internal_errors(struct pci_dev *dev);
> >>  #endif //_AER_H_
> >>  
> >> -- 
> >> 2.34.1
> >>
> >
>