diff --git a/MAINTAINERS b/MAINTAINERS
index 529c7d7ba113..96e97d25e1c2 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -20507,7 +20507,7 @@ F:	Documentation/devicetree/bindings/pci/hisilicon,kirin-pcie.yaml
 F:	drivers/pci/controller/dwc/pcie-kirin.c
 
 PCIE DRIVER FOR HISILICON STB
-M:	Shawn Guo <shawn.guo@linaro.org>
+M:	Shawn Guo <shawnguo@kernel.org>
 L:	linux-pci@vger.kernel.org
 S:	Maintained
 F:	Documentation/devicetree/bindings/pci/hisilicon-histb-pcie.txt
diff --git a/drivers/pci/controller/dwc/pcie-designware-ep.c b/drivers/pci/controller/dwc/pcie-designware-ep.c
index 295076cf70de..c57ae4d6c5c0 100644
--- a/drivers/pci/controller/dwc/pcie-designware-ep.c
+++ b/drivers/pci/controller/dwc/pcie-designware-ep.c
@@ -905,6 +905,19 @@ int dw_pcie_ep_raise_msi_irq(struct dw_pcie_ep *ep, u8 func_no,
 	 * supported, so we avoid reprogramming the region on every MSI,
 	 * specifically unmapping immediately after writel().
 	 */
+	if (ep->msi_iatu_mapped && (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 when there are
+		 * operations in flight is unsafe on this controller. However,
+		 * there is no unified way to check if we have operations in
+		 * flight, thus we don't know if we should WARN() or not.
+		 */
+		dw_pcie_ep_unmap_addr(epc, func_no, 0, ep->msi_mem_phys);
+		ep->msi_iatu_mapped = false;
+	}
+
 	if (!ep->msi_iatu_mapped) {
 		ret = dw_pcie_ep_map_addr(epc, func_no, 0,
 					  ep->msi_mem_phys, msg_addr,
@@ -915,15 +928,6 @@ int dw_pcie_ep_raise_msi_irq(struct dw_pcie_ep *ep, u8 func_no,
 		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);
@@ -1010,6 +1014,9 @@ int dw_pcie_ep_raise_msix_irq(struct dw_pcie_ep *ep, u8 func_no,
 
 	writel(msg_data, ep->msi_mem + offset);
 
+	/* flush posted write before unmap */
+	readl(ep->msi_mem + offset);
+
 	dw_pcie_ep_unmap_addr(epc, func_no, 0, ep->msi_mem_phys);
 
 	return 0;
diff --git a/include/uapi/linux/pci_regs.h b/include/uapi/linux/pci_regs.h
index ec1c54b5a310..14f634ab9350 100644
--- a/include/uapi/linux/pci_regs.h
+++ b/include/uapi/linux/pci_regs.h
@@ -712,7 +712,7 @@
 #define  PCI_EXP_LNKCTL2_HASD		0x0020 /* HW Autonomous Speed Disable */
 #define PCI_EXP_LNKSTA2		0x32	/* Link Status 2 */
 #define  PCI_EXP_LNKSTA2_FLIT		0x0400 /* Flit Mode Status */
-#define PCI_CAP_EXP_ENDPOINT_SIZEOF_V2	0x32	/* end of v2 EPs w/ link */
+#define PCI_CAP_EXP_ENDPOINT_SIZEOF_V2	0x34	/* end of v2 EPs w/ link */
 #define PCI_EXP_SLTCAP2		0x34	/* Slot Capabilities 2 */
 #define  PCI_EXP_SLTCAP2_IBPD	0x00000001 /* In-band PD Disable Supported */
 #define PCI_EXP_SLTCTL2		0x38	/* Slot Control 2 */