diff --git a/hw/serial.c b/hw/serial.c
index b0465d99..2907089c 100644
--- a/hw/serial.c
+++ b/hw/serial.c
@@ -242,36 +242,31 @@ void serial8250__inject_sysrq(struct kvm *kvm, char sysrq)
 	sysrq_pending = sysrq;
 }
 
-static bool serial8250_out(struct ioport *ioport, struct kvm_cpu *vcpu, u16 port,
-			   void *data, int size)
+static bool serial8250_out(struct serial8250_device *dev, struct kvm_cpu *vcpu,
+			   u16 offset, u8 data)
 {
-	struct serial8250_device *dev = ioport->priv;
-	u16 offset;
 	bool ret = true;
-	char *addr = data;
 
 	mutex_lock(&dev->mutex);
 
-	offset = port - dev->iobase;
-
 	switch (offset) {
 	case UART_TX:
 		if (dev->lcr & UART_LCR_DLAB) {
-			dev->dll = ioport__read8(data);
+			dev->dll = data;
 			break;
 		}
 
 		/* Loopback mode */
 		if (dev->mcr & UART_MCR_LOOP) {
 			if (dev->rxcnt < FIFO_LEN) {
-				dev->rxbuf[dev->rxcnt++] = *addr;
+				dev->rxbuf[dev->rxcnt++] = data;
 				dev->lsr |= UART_LSR_DR;
 			}
 			break;
 		}
 
 		if (dev->txcnt < FIFO_LEN) {
-			dev->txbuf[dev->txcnt++] = *addr;
+			dev->txbuf[dev->txcnt++] = data;
 			dev->lsr &= ~UART_LSR_TEMT;
 			if (dev->txcnt == FIFO_LEN / 2)
 				dev->lsr &= ~UART_LSR_THRE;
@@ -283,18 +278,18 @@ static bool serial8250_out(struct ioport *ioport, struct kvm_cpu *vcpu, u16 port
 		break;
 	case UART_IER:
 		if (!(dev->lcr & UART_LCR_DLAB))
-			dev->ier = ioport__read8(data) & 0x0f;
+			dev->ier = data & 0x0f;
 		else
-			dev->dlm = ioport__read8(data);
+			dev->dlm = data;
 		break;
 	case UART_FCR:
-		dev->fcr = ioport__read8(data);
+		dev->fcr = data;
 		break;
 	case UART_LCR:
-		dev->lcr = ioport__read8(data);
+		dev->lcr = data;
 		break;
 	case UART_MCR:
-		dev->mcr = ioport__read8(data);
+		dev->mcr = data;
 		break;
 	case UART_LSR:
 		/* Factory test */
@@ -303,7 +298,7 @@ static bool serial8250_out(struct ioport *ioport, struct kvm_cpu *vcpu, u16 port
 		/* Not used */
 		break;
 	case UART_SCR:
-		dev->scr = ioport__read8(data);
+		dev->scr = data;
 		break;
 	default:
 		ret = false;
@@ -336,46 +331,43 @@ static void serial8250_rx(struct serial8250_device *dev, void *data)
 	}
 }
 
-static bool serial8250_in(struct ioport *ioport, struct kvm_cpu *vcpu, u16 port, void *data, int size)
+static bool serial8250_in(struct serial8250_device *dev, struct kvm_cpu *vcpu,
+			  u16 offset, u8 *data)
 {
-	struct serial8250_device *dev = ioport->priv;
-	u16 offset;
 	bool ret = true;
 
 	mutex_lock(&dev->mutex);
 
-	offset = port - dev->iobase;
-
 	switch (offset) {
 	case UART_RX:
 		if (dev->lcr & UART_LCR_DLAB)
-			ioport__write8(data, dev->dll);
+			*data = dev->dll;
 		else
 			serial8250_rx(dev, data);
 		break;
 	case UART_IER:
 		if (dev->lcr & UART_LCR_DLAB)
-			ioport__write8(data, dev->dlm);
+			*data = dev->dlm;
 		else
-			ioport__write8(data, dev->ier);
+			*data = dev->ier;
 		break;
 	case UART_IIR:
-		ioport__write8(data, dev->iir | UART_IIR_TYPE_BITS);
+		*data = dev->iir | UART_IIR_TYPE_BITS;
 		break;
 	case UART_LCR:
-		ioport__write8(data, dev->lcr);
+		*data = dev->lcr;
 		break;
 	case UART_MCR:
-		ioport__write8(data, dev->mcr);
+		*data = dev->mcr;
 		break;
 	case UART_LSR:
-		ioport__write8(data, dev->lsr);
+		*data = dev->lsr;
 		break;
 	case UART_MSR:
-		ioport__write8(data, dev->msr);
+		*data = dev->msr;
 		break;
 	case UART_SCR:
-		ioport__write8(data, dev->scr);
+		*data = dev->scr;
 		break;
 	default:
 		ret = false;
@@ -389,6 +381,47 @@ static bool serial8250_in(struct ioport *ioport, struct kvm_cpu *vcpu, u16 port,
 	return ret;
 }
 
+static void serial8250_mmio(struct kvm_cpu *vcpu, u64 addr, u8 *data, u32 len,
+			    u8 is_write, void *ptr)
+{
+	struct serial8250_device *dev = ptr;
+	u8 value = 0;
+
+	if (is_write) {
+		 value = *data;
+
+		serial8250_out(dev, vcpu, addr - dev->iobase, value);
+	} else {
+		if (serial8250_in(dev, vcpu, addr - dev->iobase, &value))
+			*data = value;
+	}
+}
+
+static bool serial8250_ioport_out(struct ioport *ioport, struct kvm_cpu *vcpu,
+				  u16 port, void *data, int size)
+{
+	struct serial8250_device *dev = ioport->priv;
+	u8 value = ioport__read8(data);
+
+	serial8250_mmio(vcpu, port, &value, 1, true, dev);
+
+	return true;
+}
+
+static bool serial8250_ioport_in(struct ioport *ioport, struct kvm_cpu *vcpu,
+				 u16 port, void *data, int size)
+{
+	struct serial8250_device *dev = ioport->priv;
+	u8 value = 0;
+
+
+	serial8250_mmio(vcpu, port, &value, 1, false, dev);
+
+	ioport__write8(data, value);
+
+	return true;
+}
+
 #ifdef CONFIG_HAS_LIBFDT
 
 char *fdt_stdout_path = NULL;
@@ -427,8 +460,8 @@ void serial8250_generate_fdt_node(void *fdt, struct device_header *dev_hdr,
 #endif
 
 static struct ioport_operations serial8250_ops = {
-	.io_in			= serial8250_in,
-	.io_out			= serial8250_out,
+	.io_in			= serial8250_ioport_in,
+	.io_out			= serial8250_ioport_out,
 };
 
 static int serial8250__device_init(struct kvm *kvm,
