diff --git a/hw/ide/ahci.h b/hw/ide/ahci.h
index 68d5074b33..79a463d93c 100644
--- a/hw/ide/ahci.h
+++ b/hw/ide/ahci.h
@@ -127,7 +127,7 @@
 #define PORT_CMD_SPIN_UP          (1 << 1) /* Spin up device */
 #define PORT_CMD_START            (1 << 0) /* Enable port DMA engine */
 
-#define PORT_CMD_ICC_MASK         (0xf << 28) /* i/f ICC state mask */
+#define PORT_CMD_ICC_MASK        (0xfU << 28) /* i/f ICC state mask */
 #define PORT_CMD_ICC_ACTIVE       (0x1 << 28) /* Put i/f in active state */
 #define PORT_CMD_ICC_PARTIAL      (0x2 << 28) /* Put i/f in partial state */
 #define PORT_CMD_ICC_SLUMBER      (0x6 << 28) /* Put i/f in slumber state */