diff --git a/drivers/pci/controller/dwc/pcie-designware-ep.c b/drivers/pci/controller/dwc/pcie-designware-ep.c
index f6c54625486e..1195d401df19 100644
--- a/drivers/pci/controller/dwc/pcie-designware-ep.c
+++ b/drivers/pci/controller/dwc/pcie-designware-ep.c
@@ -601,6 +601,16 @@ static void dw_pcie_ep_stop(struct pci_epc *epc)
 	struct dw_pcie_ep *ep = epc_get_drvdata(epc);
 	struct dw_pcie *pci = to_dw_pcie_from_ep(ep);
 
+	/*
+	 * Tear down the dedicated outbound window used for MSI
+	 * generation. This avoids leaking an iATU window across
+	 * endpoint stop/start cycles.
+	 */
+	if (ep->msi_iatu_mapped) {
+		dw_pcie_ep_unmap_addr(epc, 0, 0, ep->msi_mem_phys);
+		ep->msi_iatu_mapped = false;
+	}
+
 	dw_pcie_stop_link(pci);
 }
 
@@ -702,15 +712,38 @@ int dw_pcie_ep_raise_msi_irq(struct dw_pcie_ep *ep, u8 func_no,
 	msg_addr = ((u64)msg_addr_upper) << 32 | msg_addr_lower;
 
 	msg_addr = dw_pcie_ep_align_addr(epc, msg_addr, &map_size, &offset);
-	ret = dw_pcie_ep_map_addr(epc, func_no, 0, ep->msi_mem_phys, msg_addr,
-				  map_size);
-	if (ret)
-		return ret;
+
+	/*
+	 * Program the outbound iATU once and keep it enabled.
+	 *
+	 * The spec warns that updating iATU registers while there are
+	 * operations in flight on the AXI bridge interface is not
+	 * supported, so we avoid reprogramming the region on every MSI,
+	 * specifically unmapping immediately after writel().
+	 */
+	if (!ep->msi_iatu_mapped) {
+		ret = dw_pcie_ep_map_addr(epc, func_no, 0,
+					  ep->msi_mem_phys, msg_addr,
+					  map_size);
+		if (ret)
+			return ret;
+
+		ep->msi_iatu_mapped = true;
+		ep->msi_msg_addr = msg_addr;
+		ep->msi_map_size = map_size;
+	} else if (WARN_ON_ONCE(ep->msi_msg_addr != msg_addr ||
+				ep->msi_map_size != map_size)) {
+		/*
+		 * The host changed the MSI target address or the required
+		 * mapping size changed. Reprogramming the iATU at runtime is
+		 * unsafe on this controller, so bail out instead of trying to
+		 * update the existing region.
+		 */
+		return -EINVAL;
+	}
 
 	writel(msg_data | (interrupt_num - 1), ep->msi_mem + offset);
 
-	dw_pcie_ep_unmap_addr(epc, func_no, 0, ep->msi_mem_phys);
-
 	return 0;
 }
 EXPORT_SYMBOL_GPL(dw_pcie_ep_raise_msi_irq);
@@ -1087,6 +1120,9 @@ int dw_pcie_ep_init(struct dw_pcie_ep *ep)
 	struct device *dev = pci->dev;
 
 	INIT_LIST_HEAD(&ep->func_list);
+	ep->msi_iatu_mapped = false;
+	ep->msi_msg_addr = 0;
+	ep->msi_map_size = 0;
 
 	epc = devm_pci_epc_create(dev, &epc_ops);
 	if (IS_ERR(epc)) {
diff --git a/drivers/pci/controller/dwc/pcie-designware.h b/drivers/pci/controller/dwc/pcie-designware.h
index a3a3f6e89a81..f87c67a7a482 100644
--- a/drivers/pci/controller/dwc/pcie-designware.h
+++ b/drivers/pci/controller/dwc/pcie-designware.h
@@ -482,6 +482,11 @@ struct dw_pcie_ep {
 	void __iomem		*msi_mem;
 	phys_addr_t		msi_mem_phys;
 	struct pci_epf_bar	*epf_bar[PCI_STD_NUM_BARS];
+
+	/* MSI outbound iATU state */
+	bool			msi_iatu_mapped;
+	u64			msi_msg_addr;
+	size_t			msi_map_size;
 };
 
 struct dw_pcie_ops {