diff --git a/hw/arm/stm32l4x5_soc.c b/hw/arm/stm32l4x5_soc.c
index 38f7a2d5d9..fac83d349c 100644
--- a/hw/arm/stm32l4x5_soc.c
+++ b/hw/arm/stm32l4x5_soc.c
@@ -81,6 +81,10 @@ static const int exti_irq[NUM_EXTI_IRQ] = {
 #define RCC_BASE_ADDRESS 0x40021000
 #define RCC_IRQ 5
 
+#define EXTI_USART1_IRQ 26
+#define EXTI_UART4_IRQ 29
+#define EXTI_LPUART1_IRQ 31
+
 static const int exti_or_gates_out[NUM_EXTI_OR_GATES] = {
     23, 40, 63, 1,
 };
@@ -129,10 +133,6 @@ static const hwaddr uart_addr[] = {
 
 #define LPUART_BASE_ADDRESS 0x40008000
 
-static const int usart_irq[] = { 37, 38, 39 };
-static const int uart_irq[] = { 52, 53 };
-#define LPUART_IRQ 70
-
 static void stm32l4x5_soc_initfn(Object *obj)
 {
     Stm32l4x5SocState *s = STM32L4X5_SOC(obj);
@@ -297,6 +297,7 @@ static void stm32l4x5_soc_realize(DeviceState *dev_soc, Error **errp)
         }
     }
 
+    /* Connect SYSCFG to EXTI */
     for (unsigned i = 0; i < GPIO_NUM_PINS; i++) {
         qdev_connect_gpio_out(DEVICE(&s->syscfg), i,
                               qdev_get_gpio_in(DEVICE(&s->exti), i));
@@ -322,15 +323,10 @@ static void stm32l4x5_soc_realize(DeviceState *dev_soc, Error **errp)
             return;
         }
         sysbus_mmio_map(busdev, 0, usart_addr[i]);
-        sysbus_connect_irq(busdev, 0, qdev_get_gpio_in(armv7m, usart_irq[i]));
+        sysbus_connect_irq(busdev, 0, qdev_get_gpio_in(DEVICE(&s->exti),
+                                                       EXTI_USART1_IRQ + i));
     }
 
-    /*
-     * TODO: Connect the USARTs, UARTs and LPUART to the EXTI once the EXTI
-     * can handle other gpio-in than the gpios. (e.g. Direct Lines for the
-     * usarts)
-     */
-
     /* UART devices */
     for (int i = 0; i < STM_NUM_UARTS; i++) {
         g_autofree char *name = g_strdup_printf("uart%d-out", STM_NUM_USARTS + i + 1);
@@ -343,7 +339,8 @@ static void stm32l4x5_soc_realize(DeviceState *dev_soc, Error **errp)
             return;
         }
         sysbus_mmio_map(busdev, 0, uart_addr[i]);
-        sysbus_connect_irq(busdev, 0, qdev_get_gpio_in(armv7m, uart_irq[i]));
+        sysbus_connect_irq(busdev, 0, qdev_get_gpio_in(DEVICE(&s->exti),
+                                                       EXTI_UART4_IRQ + i));
     }
 
     /* LPUART device*/
@@ -356,7 +353,8 @@ static void stm32l4x5_soc_realize(DeviceState *dev_soc, Error **errp)
         return;
     }
     sysbus_mmio_map(busdev, 0, LPUART_BASE_ADDRESS);
-    sysbus_connect_irq(busdev, 0, qdev_get_gpio_in(armv7m, LPUART_IRQ));
+    sysbus_connect_irq(busdev, 0, qdev_get_gpio_in(DEVICE(&s->exti),
+                                                   EXTI_LPUART1_IRQ));
 
     /* APB1 BUS */
     create_unimplemented_device("TIM2",      0x40000000, 0x400);