Re: [PATCH v20 4/9] cxl/pci: Thread port and dport through RAS handling helpers

On 9/2/2026 8:39 AM, Terry Bowman wrote:
> From: Dan Williams <[email protected]>
> 
> The callers of cxl_handle_ras() and cxl_handle_cor_ras() already hold
> a struct cxl_port * and optionally a struct cxl_dport * for the device
> being handled. Passing a generic struct device * requires is_cxl_memdev()
> to distinguish Endpoints from Ports at trace emission time. Threading
> Port and Downstream Port directly enables is_cxl_endpoint() and explicit
> dport/port branching for cleaner trace dispatch.
> 
> Refactor cxl_handle_ras() and cxl_handle_cor_ras() to accept struct
> cxl_port * and struct cxl_dport * directly. The CXL RAS trace event
> emission logic is split into three branches: Endpoint events are
> identified via is_cxl_endpoint() and emit with the memdev, dport events
> emit with dport->dport_dev, and Upstream Port events fall back to
> port->uport_dev. This branching is transitional: the follow-on patch
> ("cxl: Add port and dport identifiers to CXL AER trace events") unifies
> the trace events on port/dport and removes it.
> 
> Update cxl_handle_rdport_errors() and cxl_handle_proto_error() to pass
> Port and Downstream Port to the refactored functions.
> 
> RCH Downstream Port correctable trace events now report the dport device
> (dport->dport_dev) as a consequence of threading Port and Downstream
> Port through the RAS helpers. The following trace event rework ("cxl: Add
> port and dport identifiers to CXL AER trace events") adds explicit memdev,
> Port, Downstream Port, and host fields that provide full context for all
> device types.
> 
> Co-developed-by: Terry Bowman <[email protected]>
> Signed-off-by: Terry Bowman <[email protected]>
> Signed-off-by: Dan Williams <[email protected]>
> Reviewed-by: Dave Jiang <[email protected]>
> Reviewed-by: Alison Schofield <[email protected]>
> 
> ---
> 
> Changes in v19 -> v20:
> - None
> 
> Changes in v18 -> v19:
> - Added review-by for DaveJ
> - Update commit message that three-way trace branching is transitional
>   and removed by the following trace-event unification patch
> 
> Changes in v17 -> v18:
> - New patch.
> ---
>  drivers/cxl/core/core.h    | 12 ++++++++----
>  drivers/cxl/core/ras.c     | 29 +++++++++++++++--------------
>  drivers/cxl/core/ras_rch.c |  2 +-
>  3 files changed, 24 insertions(+), 19 deletions(-)
> 
> diff --git a/drivers/cxl/core/core.h b/drivers/cxl/core/core.h
> index 645824167f788..4f6b4702deb38 100644
> --- a/drivers/cxl/core/core.h
> +++ b/drivers/cxl/core/core.h
> @@ -187,10 +187,12 @@ static inline struct device *dport_to_host(struct cxl_dport *dport)
>  #ifdef CONFIG_CXL_RAS
>  void cxl_ras_init(void);
>  void cxl_ras_exit(void);
> -bool cxl_handle_ras(struct device *dev, void __iomem *ras_base);
> +bool cxl_handle_ras(struct cxl_port *port, struct cxl_dport *dport,
> +		    void __iomem *ras_base);
>  void cxl_do_recovery(struct pci_dev *pdev, struct cxl_port *port,
>  		     struct cxl_dport *dport);
> -void cxl_handle_cor_ras(struct device *dev, void __iomem *ras_base);
> +void cxl_handle_cor_ras(struct cxl_port *port, struct cxl_dport *dport,
> +			void __iomem *ras_base);
>  void cxl_dport_map_rch_aer(struct cxl_dport *dport);
>  void cxl_disable_rch_root_ints(struct cxl_dport *dport);
>  void cxl_handle_rdport_errors(struct pci_dev *pdev);
> @@ -199,13 +201,15 @@ void devm_cxl_dport_ras_setup(struct cxl_dport *dport);
>  #else
>  static inline void cxl_ras_init(void) { }
>  static inline void cxl_ras_exit(void) { }
> -static inline bool cxl_handle_ras(struct device *dev, void __iomem *ras_base)
> +static inline bool cxl_handle_ras(struct cxl_port *port, struct cxl_dport *dport,
> +				  void __iomem *ras_base)
>  {
>  	return false;
>  }
>  static inline void cxl_do_recovery(struct pci_dev *pdev, struct cxl_port *port,
>  				   struct cxl_dport *dport) { }
> -static inline void cxl_handle_cor_ras(struct device *dev, void __iomem *ras_base) { }
> +static inline void cxl_handle_cor_ras(struct cxl_port *port, struct cxl_dport *dport,
> +				      void __iomem *ras_base) { }
>  static inline void cxl_dport_map_rch_aer(struct cxl_dport *dport) { }
>  static inline void cxl_disable_rch_root_ints(struct cxl_dport *dport) { }
>  static inline void cxl_handle_rdport_errors(struct pci_dev *pdev) { }
> diff --git a/drivers/cxl/core/ras.c b/drivers/cxl/core/ras.c
> index 02c791f149270..e99dcd028b738 100644
> --- a/drivers/cxl/core/ras.c
> +++ b/drivers/cxl/core/ras.c
> @@ -227,20 +227,19 @@ void __iomem *to_ras_base(struct cxl_port *port, struct cxl_dport *dport)
>  
>  void cxl_do_recovery(struct pci_dev *pdev, struct cxl_port *port, struct cxl_dport *dport)
>  {
> -	struct device *dev = dport ? dport->dport_dev : port->uport_dev;
>  	void __iomem *ras_base = to_ras_base(port, dport);
>  
>  	if (!ras_base)
>  		panic("CXL: UCE with unmapped RAS registers");
>  
> -	if (cxl_handle_ras(dev, ras_base))
> +	if (cxl_handle_ras(port, dport, ras_base))

I haven't looked ahead, and maybe I'm missing something, but why not have cxl_handle_ras() just
take the port & dport and call to_ras_base() internally? It's not a big deal, but it would
make the call in cxl_error_detected() a lot prettier.

Either way:
Reviewed-by: Ben Cheatham <[email protected]>
>  		panic("CXL cachemem error");
>  
>  	dev_dbg(&pdev->dev,
>  		"CXL UCE signaled but no CXL RAS status bits set\n");
>  }
>  
> -void cxl_handle_cor_ras(struct device *dev, void __iomem *ras_base)
> +void cxl_handle_cor_ras(struct cxl_port *port, struct cxl_dport *dport, void __iomem *ras_base)
>  {
>  	void __iomem *addr;
>  	u32 status;
> @@ -252,10 +251,12 @@ void cxl_handle_cor_ras(struct device *dev, void __iomem *ras_base)
>  	status = readl(addr);
>  	if (status & CXL_RAS_CORRECTABLE_STATUS_MASK) {
>  		writel(status & CXL_RAS_CORRECTABLE_STATUS_MASK, addr);
> -		if (is_cxl_memdev(dev))
> -			trace_cxl_aer_correctable_error(to_cxl_memdev(dev), status);
> +		if (is_cxl_endpoint(port))
> +			trace_cxl_aer_correctable_error(to_cxl_memdev(port->uport_dev), status);
> +		else if (dport)
> +			trace_cxl_port_aer_correctable_error(dport->dport_dev, status);
>  		else
> -			trace_cxl_port_aer_correctable_error(dev, status);
> +			trace_cxl_port_aer_correctable_error(port->uport_dev, status);
>  	}
>  }
>  
> @@ -280,7 +281,7 @@ static void header_log_copy(void __iomem *ras_base, u32 *log)
>   * Log the state of the RAS status registers and prepare them to log the
>   * next error status. Return 1 if reset needed.
>   */
> -bool cxl_handle_ras(struct device *dev, void __iomem *ras_base)
> +bool cxl_handle_ras(struct cxl_port *port, struct cxl_dport *dport, void __iomem *ras_base)
>  {
>  	u32 hl[CXL_HEADERLOG_TRACE_SIZE_U32] = {};
>  	void __iomem *addr;
> @@ -307,10 +308,12 @@ bool cxl_handle_ras(struct device *dev, void __iomem *ras_base)
>  	}
>  
>  	header_log_copy(ras_base, hl);
> -	if (is_cxl_memdev(dev))
> -		trace_cxl_aer_uncorrectable_error(to_cxl_memdev(dev), status, fe, hl);
> +	if (is_cxl_endpoint(port))
> +		trace_cxl_aer_uncorrectable_error(to_cxl_memdev(port->uport_dev), status, fe, hl);
> +	else if (dport)
> +		trace_cxl_port_aer_uncorrectable_error(dport->dport_dev, status, fe, hl);
>  	else
> -		trace_cxl_port_aer_uncorrectable_error(dev, status, fe, hl);
> +		trace_cxl_port_aer_uncorrectable_error(port->uport_dev, status, fe, hl);
>  
>  	writel(status & CXL_RAS_UNCORRECTABLE_STATUS_MASK, addr);
>  
> @@ -344,7 +347,7 @@ pci_ers_result_t cxl_error_detected(struct pci_dev *pdev,
>  		 * cache coherency is already lost; continuing risks silent
>  		 * data corruption.
>  		 */
> -		ue = cxl_handle_ras(port->uport_dev, to_ras_base(port, NULL));
> +		ue = cxl_handle_ras(port, NULL, to_ras_base(port, NULL));
>  	}
>  
>  	/*
> @@ -375,10 +378,8 @@ EXPORT_SYMBOL_NS_GPL(cxl_error_detected, "CXL");
>  static void cxl_handle_proto_error(struct pci_dev *pdev, struct cxl_port *port,
>  				   struct cxl_dport *dport, int severity)
>  {
> -	struct device *dev = dport ? dport->dport_dev : port->uport_dev;
> -
>  	if (severity == AER_CORRECTABLE)
> -		cxl_handle_cor_ras(dev, to_ras_base(port, dport));
> +		cxl_handle_cor_ras(port, dport, to_ras_base(port, dport));
>  	else
>  		cxl_do_recovery(pdev, port, dport);
>  }
> diff --git a/drivers/cxl/core/ras_rch.c b/drivers/cxl/core/ras_rch.c
> index 285eed5b828b9..bc6cf50fcc926 100644
> --- a/drivers/cxl/core/ras_rch.c
> +++ b/drivers/cxl/core/ras_rch.c
> @@ -123,7 +123,7 @@ void cxl_handle_rdport_errors(struct pci_dev *pdev)
>  	 */
>  	if (aer_regs.cor_status & ~aer_regs.cor_mask) {
>  		pci_print_aer(pdev, AER_CORRECTABLE, &aer_regs);
> -		cxl_handle_cor_ras(dport->dport_dev, to_ras_base(port, dport));
> +		cxl_handle_cor_ras(port, dport, to_ras_base(port, dport));
>  	}
>  
>  	if (uncor_status) {