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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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        Jonathan Cameron <Jonathan.Cameron@Huawei.com>,
        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 v3 1/3] cxl/pci: Fix appropriate checking for _OSC while handling CXL RAS registers
Date:   Thu, 3 Aug 2023 23:01:27 +0000
Message-ID: <20230803230129.127590-2-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.

This change fixes handling and reporting CXL Protocol Errors and RAS
registers natively with native AER and FW-First CXL Memory Error Reporting
Control.

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

Fixes: 248529edc86f ("cxl: add RAS status unmasking for CXL")
Signed-off-by: Smita Koralahalli <Smita.KoralahalliChannabasappa@amd.com>
Reviewed-by: Robert Richter <rrichter@amd.com>
---
v2:
	Added fixes tag.
	Included what the patch fixes in commit message.
v3:
	Added "Reviewed-by" tag.
---
 drivers/cxl/pci.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/cxl/pci.c b/drivers/cxl/pci.c
index 1cb1494c28fe..2323169b6e5f 100644
--- a/drivers/cxl/pci.c
+++ b/drivers/cxl/pci.c
@@ -541,9 +541,9 @@ 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 (!host_bridge->native_aer)
+		return 0;
 
 	rc = pcie_capability_read_word(pdev, PCI_EXP_DEVCTL, &cap);
 	if (rc)
-- 
2.17.1