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From:   Smita Koralahalli <Smita.KoralahalliChannabasappa@amd.com>
To:     <linux-pci@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
        <linux-cxl@vger.kernel.org>
CC:     Bjorn Helgaas <bhelgaas@google.com>, <oohall@gmail.com>,
        Lukas Wunner <lukas@wunner.de>,
        Kuppuswamy Sathyanarayanan 
        <sathyanarayanan.kuppuswamy@linux.intel.com>,
        Mahesh J Salgaonkar <mahesh@linux.ibm.com>,
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        Yazen Ghannam <yazen.ghannam@amd.com>,
        Terry Bowman <terry.bowman@amd.com>,
        Robert Richter <rrichter@amd.com>,
        Smita Koralahalli <Smita.KoralahalliChannabasappa@amd.com>
Subject: [PATCH 2/2] cxl/pci: Fix appropriate checking for _OSC while handling CXL RAS registers
Date:   Wed, 19 Jul 2023 19:23:13 +0000
Message-ID: <20230719192313.38591-3-Smita.KoralahalliChannabasappa@amd.com>
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According to Section 9.17.2, Table 9-26 of CXL Specification [1], owner
of AER should also own CXL Protocol Error Management as there is no
explicit control of CXL Protocol error. And the CXL RAS Cap registers
reported on Protocol errors should check for AER _OSC rather than CXL
Memory Error Reporting Control _OSC.

The CXL Memory Error Reporting Control _OSC specifically highlights
handling Memory Error Logging and Signaling Enhancements. These kinds of
errors are reported through a device's mailbox and can be managed
independently from CXL Protocol Errors.

[1] Compute Express Link (CXL) Specification, Revision 3.1, Aug 1 2022.

Signed-off-by: Smita Koralahalli <Smita.KoralahalliChannabasappa@amd.com>
---
 drivers/cxl/pci.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/drivers/cxl/pci.c b/drivers/cxl/pci.c
index 1cb1494c28fe..44a21ab7add5 100644
--- a/drivers/cxl/pci.c
+++ b/drivers/cxl/pci.c
@@ -529,7 +529,6 @@ static int cxl_pci_setup_regs(struct pci_dev *pdev, enum cxl_regloc_type type,
 
 static int cxl_pci_ras_unmask(struct pci_dev *pdev)
 {
-	struct pci_host_bridge *host_bridge = pci_find_host_bridge(pdev->bus);
 	struct cxl_dev_state *cxlds = pci_get_drvdata(pdev);
 	void __iomem *addr;
 	u32 orig_val, val, mask;
@@ -541,9 +540,9 @@ static int cxl_pci_ras_unmask(struct pci_dev *pdev)
 		return 0;
 	}
 
-	/* BIOS has CXL error control */
-	if (!host_bridge->native_cxl_error)
-		return -ENXIO;
+	/* BIOS has PCIe AER error control */
+	if (!pcie_aer_is_native(pdev))
+		return 0;
 
 	rc = pcie_capability_read_word(pdev, PCI_EXP_DEVCTL, &cap);
 	if (rc)
-- 
2.17.1