[PATCH 6.18.y] cxl/pci: Use the Device GPF DVSEC for restricted endpoints

[Sasha Levin <sashal@kernel.org>]

From: Guixin Liu <kanie@linux.alibaba.com>

[ Upstream commit d2654fa0d841fa36ffa76577f83a2810d643ae19 ]

cxl_gpf_get_dvsec() picks between the Port and the Device GPF DVSEC
from the PCIe type of the given device, and only a plain endpoint
counts as a device. A restricted CXL device is an endpoint too, but
it falls into the port case and is probed for the Port GPF DVSEC
instead of the Device GPF DVSEC.

On an RCD, dirty shutdown tracking therefore never arms: the DVSEC
lookup in cxl_nvdimm_arm_dirty_shutdown_tracking() fails, the dirty
shutdown count stays invalid, and the warning complains about a
missing Port GPF DVSEC on a device.

Treat restricted endpoints as devices.

Fixes: 36aace15d9bd ("cxl/pci: Drop the parameter is_port of cxl_gpf_get_dvsec()")
Cc: stable@vger.kernel.org
Assisted-by: LLM
Signed-off-by: Guixin Liu <kanie@linux.alibaba.com>
Reviewed-by: Jonathan Cameron <jonathan.cameron@oss.qualcomm.com>
Reviewed-by: Dave Jiang <dave.jiang@intel.com>
Reviewed-by: Alison Schofield <alison.schofield@intel.com>
Link: https://patch.msgid.link/20261008034619.28059-2-kanie@linux.alibaba.com
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
[ sashal: Replaced the unavailable is_cxl_restricted() helper call with the equivalent pci_pcie_type(pdev) == PCI_EXP_TYPE_RC_END comparison. ]
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/cxl/core/pci.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/cxl/core/pci.c b/drivers/cxl/core/pci.c
index 48c1f3854b799..d2ee7d853f1fd 100644
--- a/drivers/cxl/core/pci.c
+++ b/drivers/cxl/core/pci.c
@@ -819,7 +819,8 @@ u16 cxl_gpf_get_dvsec(struct device *dev)
 		return 0;
 
 	pdev = to_pci_dev(dev);
-	if (pci_pcie_type(pdev) == PCI_EXP_TYPE_ENDPOINT)
+	if (pci_pcie_type(pdev) == PCI_EXP_TYPE_ENDPOINT ||
+	    pci_pcie_type(pdev) == PCI_EXP_TYPE_RC_END)
 		is_port = false;
 
 	dvsec = pci_find_dvsec_capability(pdev, PCI_VENDOR_ID_CXL,
-- 
2.53.0