diff --git a/drivers/cxl/core/features.c b/drivers/cxl/core/features.c
index 738a89863ee8..8731b95dd0b5 100644
--- a/drivers/cxl/core/features.c
+++ b/drivers/cxl/core/features.c
@@ -240,6 +240,8 @@ size_t cxl_get_feature(struct cxl_mailbox *cxl_mbox, const uuid_t *feat_uuid,
 	size_out = min(feat_out_size, cxl_mbox->payload_size);
 	uuid_copy(&pi.uuid, feat_uuid);
 	pi.selection = selection;
+
+	guard(mutex)(&cxl_mbox->feat_mutex);
 	do {
 		data_to_rd_size = min(feat_out_size - data_rcvd_size,
 				      cxl_mbox->payload_size);
@@ -314,6 +316,7 @@ int cxl_set_feature(struct cxl_mailbox *cxl_mbox,
 		data_in_size = cxl_mbox->payload_size - hdr_size;
 	}
 
+	guard(mutex)(&cxl_mbox->feat_mutex);
 	do {
 		int rc;
 
diff --git a/drivers/cxl/core/mbox.c b/drivers/cxl/core/mbox.c
index 241526bb9e80..cc479f4322e7 100644
--- a/drivers/cxl/core/mbox.c
+++ b/drivers/cxl/core/mbox.c
@@ -1516,6 +1516,7 @@ int cxl_mailbox_init(struct cxl_mailbox *cxl_mbox, struct device *host)
 
 	cxl_mbox->host = host;
 	mutex_init(&cxl_mbox->mbox_mutex);
+	mutex_init(&cxl_mbox->feat_mutex);
 	rcuwait_init(&cxl_mbox->mbox_wait);
 
 	return 0;
diff --git a/include/cxl/mailbox.h b/include/cxl/mailbox.h
index c4e99e2e3a9d..d008b9db07aa 100644
--- a/include/cxl/mailbox.h
+++ b/include/cxl/mailbox.h
@@ -50,6 +50,7 @@ struct cxl_mbox_cmd {
  * @payload_size: Size of space for payload
  *                (CXL 3.1 8.2.8.4.3 Mailbox Capabilities Register)
  * @mbox_mutex: mutex protects device mailbox and firmware
+ * @feat_mutex: serializes multi-part Get/Set Feature transfers
  * @mbox_wait: rcuwait for mailbox
  * @mbox_send: @dev specific transport for transmitting mailbox commands
  * @feat_cap: Features capability
@@ -60,6 +61,7 @@ struct cxl_mailbox {
 	DECLARE_BITMAP(exclusive_cmds, CXL_MEM_COMMAND_ID_MAX);
 	size_t payload_size;
 	struct mutex mbox_mutex; /* lock to protect mailbox context */
+	struct mutex feat_mutex;
 	struct rcuwait mbox_wait;
 	int (*mbox_send)(struct cxl_mailbox *cxl_mbox, struct cxl_mbox_cmd *cmd);
 	enum cxl_features_capability feat_cap;