linux-kernel - [RFC PATCH 4/6] PCI/AER: Extend RCH RAS error handling to support VH topology case

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Message-Id: <20240313083602.239201-5-ming4.li@intel.com>
Date: Wed, 13 Mar 2024 08:36:00 +0000
From: Li Ming <ming4.li@...el.com>
To: dan.j.williams@...el.com,
	rrichter@....com,
	terry.bowman@....com
Cc: linux-cxl@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	Li Ming <ming4.li@...el.com>
Subject: [RFC PATCH 4/6] PCI/AER: Extend RCH RAS error handling to support VH topology case

When RCEC captures CXL.cachemem protocol errors detected by CXL root
port, the recommendation from CXL r3.1 9.18.1.5 is :

	"Probe all CXL Downstream Ports and determine whether they have logged an
	error in the CXL.io or CXL.cachemem status registers."

The flow is similar with RCH RAS error handling, so reuse it to support
above case.

Signed-off-by: Li Ming <ming4.li@...el.com>
---
 drivers/pci/pcie/aer.c | 20 ++++++++++++--------
 1 file changed, 12 insertions(+), 8 deletions(-)

diff --git a/drivers/pci/pcie/aer.c b/drivers/pci/pcie/aer.c
index 364c74e47273..79bfa5fb78f4 100644
--- a/drivers/pci/pcie/aer.c
+++ b/drivers/pci/pcie/aer.c
@@ -996,11 +996,15 @@ static bool is_internal_error(struct aer_err_info *info)
 	return info->status & PCI_ERR_UNC_INTN;
 }
 
-static int cxl_rch_handle_error_iter(struct pci_dev *dev, void *data)
+static int cxl_handle_error_iter(struct pci_dev *dev, void *data)
 {
 	struct aer_err_info *info = (struct aer_err_info *)data;
 	const struct pci_error_handlers *err_handler;
 
+	/* Skip the RCiEP devices not associating with RCEC */
+	if ((pci_pcie_type(dev) == PCI_EXP_TYPE_RC_END) &&
+	    !dev->rcec)
+		return 0;
 	if (!is_cxl_mem_dev(dev) || !cxl_error_is_native(dev))
 		return 0;
 
@@ -1025,16 +1029,16 @@ static int cxl_rch_handle_error_iter(struct pci_dev *dev, void *data)
 	return 0;
 }
 
-static void cxl_rch_handle_error(struct pci_dev *dev, struct aer_err_info *info)
+static void cxl_handle_error(struct pci_dev *dev, struct aer_err_info *info)
 {
 	/*
 	 * Internal errors of an RCEC indicate an AER error in an
-	 * RCH's downstream port. Check and handle them in the CXL.mem
-	 * device driver.
+	 * RCH's downstream port or a CXL root port. Check and handle
+	 * them in the CXL.mem device driver.
 	 */
 	if (pci_pcie_type(dev) == PCI_EXP_TYPE_RC_EC &&
 	    is_internal_error(info))
-		pcie_walk_rcec(dev, cxl_rch_handle_error_iter, info);
+		pcie_walk_rcec_all(dev, cxl_handle_error_iter, info);
 }
 
 static int handles_cxl_error_iter(struct pci_dev *dev, void *data)
@@ -1080,8 +1084,8 @@ static void cxl_enable_rcec(struct pci_dev *rcec)
 
 #else
 static inline void cxl_enable_rcec(struct pci_dev *dev) { }
-static inline void cxl_rch_handle_error(struct pci_dev *dev,
-					struct aer_err_info *info) { }
+static inline void cxl_handle_error(struct pci_dev *dev,
+				    struct aer_err_info *info) { }
 #endif
 
 /**
@@ -1119,7 +1123,7 @@ static void pci_aer_handle_error(struct pci_dev *dev, struct aer_err_info *info)
 
 static void handle_error_source(struct pci_dev *dev, struct aer_err_info *info)
 {
-	cxl_rch_handle_error(dev, info);
+	cxl_handle_error(dev, info);
 	pci_aer_handle_error(dev, info);
 	pci_dev_put(dev);
 }
-- 
2.40.1