[PATCH v11 08/12] PCI/CXL: Reject CXL Reset on multifunction devices

[Srirangan Madhavan]

CXL Reset can be exposed as a PCI function reset method only when the
reset is function-scoped. PCI reset-method probing runs during
enumeration, so walking sibling functions there can race with functions
that have not been added to the bus yet.

Reject multifunction devices for now instead of trying to infer reset
scope from sibling state. Systems that can prove a multifunction device
has function-scoped CXL Reset can be enabled later.

Signed-off-by: Srirangan Madhavan <smadhavan@xxxxxxxxxx>
Reviewed-by: Dave Jiang <dave.jiang@xxxxxxxxx>
---
 drivers/cxl/core/resource.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/cxl/core/resource.c b/drivers/cxl/core/resource.c
index 13bd0c3faf7e..79227ce70169 100644
--- a/drivers/cxl/core/resource.c
+++ b/drivers/cxl/core/resource.c
@@ -979,6 +979,9 @@ int cxl_reset_function(struct pci_dev *pdev, bool probe)
 	if (dvsec < 0)
 		return dvsec;
 
+	if (pdev->multifunction)
+		return -ENOTTY;
+
 	if (probe)
 		return 0;
 
-- 
2.43.0