[PATCH 6.18 377/641] cxl/core: Fix cxl_dport debugfs EINJ entries

Greg Kroah-Hartman
2026-02-25T06:57:24Z

6.18-stable review patch. If anyone has any objections, please let me know.

------------------

From: Cheatham, Benjamin <benjamin.cheatham@amd.com>

[ Upstream commit 4ed7952b9e87cf731ebc8251874416e60eb15230 ]

Protocol error injection is only valid for CXL 2.0+ root ports and CXL
1.1 memory-mapped downstream ports as per the ACPI v6.5 spec (Table
8-31). The core code currently creates an 'einj_inject' file in CXL debugfs
for all CXL 1.1 downstream ports and all PCI CXL 2.0+ downstream ports.
This results in debugfs EINJ files that won't work due to platform/spec
restrictions.

Fix by limiting 'einj_inject' file creation to only CXL 1.1 dports and
CXL 2.0+ root ports. Update the comment above the check to more accurately
represent the requirements expected by the EINJ module and ACPI spec.

Fixes: 8039804cfa73 ("cxl/core: Add CXL EINJ debugfs files")
Signed-off-by: Ben Cheatham <Benjamin.Cheatham@amd.com>
Reviewed-by: Jonathan Cameron <jonathan.cameron@huawei.com>
Reviewed-by: Alison Schofield <alison.schofield@intel.com>
Reviewed-by: Dave Jiang <dave.jiang@intel.com>
Link: https://patch.msgid.link/6e9fb657-8264-4028-92e2-5428e2695bf1@amd.com
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/cxl/core/port.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/drivers/cxl/core/port.c b/drivers/cxl/core/port.c
index 804e4a48540f6..85131872d7f6e 100644
--- a/drivers/cxl/core/port.c
+++ b/drivers/cxl/core/port.c
@@ -823,16 +823,18 @@ DEFINE_DEBUGFS_ATTRIBUTE(cxl_einj_inject_fops, NULL, cxl_einj_inject,

static void cxl_debugfs_create_dport_dir(struct cxl_dport *dport)
{
+ struct cxl_port *parent = parent_port_of(dport->port);
struct dentry *dir;

if (!einj_cxl_is_initialized())
return;

/*
- * dport_dev needs to be a PCIe port for CXL 2.0+ ports because
- * EINJ expects a dport SBDF to be specified for 2.0 error injection.
+ * Protocol error injection is only available for CXL 2.0+ root ports
+ * and CXL 1.1 downstream ports
*/
- if (!dport->rch && !dev_is_pci(dport->dport_dev))
+ if (!dport->rch &&
+ !(dev_is_pci(dport->dport_dev) && parent && is_cxl_root(parent)))
return;

dir = cxl_debugfs_create_dir(dev_name(dport->dport_dev));
--
2.51.0