diff --git a/drivers/ntb/hw/epf/ntb_hw_epf.c b/drivers/ntb/hw/epf/ntb_hw_epf.c
index c0bab3292075..7b0fc7ef00c6 100644
--- a/drivers/ntb/hw/epf/ntb_hw_epf.c
+++ b/drivers/ntb/hw/epf/ntb_hw_epf.c
@@ -81,6 +81,12 @@ enum epf_ntb_bar {
 	NTB_BAR_NUM,
 };
 
+enum epf_irq_slot {
+	EPF_IRQ_LINK = 0,
+	EPF_IRQ_RESERVED_DB, /* Historically skipped slot */
+	EPF_IRQ_DB_START,
+};
+
 #define NTB_EPF_MAX_MW_COUNT	(NTB_BAR_NUM - BAR_MW1)
 
 struct ntb_epf_dev {
@@ -334,10 +340,14 @@ static irqreturn_t ntb_epf_vec_isr(int irq, void *dev)
 	irq_no = irq - ndev->irq_base;
 	ndev->db_val = irq_no + 1;
 
-	if (irq_no == 0)
+	if (irq_no == EPF_IRQ_LINK) {
 		ntb_link_event(&ndev->ntb);
-	else
-		ntb_db_event(&ndev->ntb, irq_no);
+	} else if (irq_no == EPF_IRQ_RESERVED_DB) {
+		dev_warn_ratelimited(ndev->dev,
+				     "Unexpected reserved doorbell slot IRQ received\n");
+	} else {
+		ntb_db_event(&ndev->ntb, irq_no - EPF_IRQ_DB_START);
+	}
 
 	return IRQ_HANDLED;
 }