diff --git a/hypervisor/arch/x86/assign.c b/hypervisor/arch/x86/assign.c
index 3469c3c9c..89760ef1f 100644
--- a/hypervisor/arch/x86/assign.c
+++ b/hypervisor/arch/x86/assign.c
@@ -629,7 +629,6 @@ int ptdev_msix_remap(struct vm *vm, uint16_t virt_bdf,
 		struct ptdev_msi_info *info)
 {
 	struct ptdev_remapping_info *entry;
-	bool lowpri = !is_vm0(vm);
 
 	/*
 	 * Device Model should pre-hold the mapping entries by calling
@@ -668,7 +667,7 @@ int ptdev_msix_remap(struct vm *vm, uint16_t virt_bdf,
 
 	if (!is_entry_active(entry)) {
 		/* update msi source and active entry */
-		ptdev_activate_entry(entry, IRQ_INVALID, lowpri);
+		ptdev_activate_entry(entry, IRQ_INVALID);
 	}
 
 	/* build physical config MSI, update to info->pmsi_xxx */
@@ -738,7 +737,6 @@ int ptdev_intx_pin_remap(struct vm *vm, struct ptdev_intx_info *info)
 	union ioapic_rte rte;
 	uint32_t phys_irq;
 	uint8_t phys_pin;
-	bool lowpri = !is_vm0(vm);
 	bool need_switch_vpin_src = false;
 	struct ptdev_intx_info *intx;
 
@@ -874,7 +872,7 @@ int ptdev_intx_pin_remap(struct vm *vm, struct ptdev_intx_info *info)
 		activate_physical_ioapic(vm, entry);
 	} else {
 		/* active entry */
-		ptdev_activate_entry(entry, phys_irq, lowpri);
+		ptdev_activate_entry(entry, phys_irq);
 
 		activate_physical_ioapic(vm, entry);
 
diff --git a/hypervisor/arch/x86/guest/vioapic.c b/hypervisor/arch/x86/guest/vioapic.c
index 7e2d05acd..4692094c0 100644
--- a/hypervisor/arch/x86/guest/vioapic.c
+++ b/hypervisor/arch/x86/guest/vioapic.c
@@ -472,7 +472,7 @@ vioapic_process_eoi(struct vm *vm, uint32_t vector)
 	uint32_t pin, pincount = vioapic_pincount(vm);
 	union ioapic_rte rte;
 
-	if (vector < VECTOR_FOR_INTR_START || vector > NR_MAX_VECTOR) {
+	if (vector < VECTOR_DYNAMIC_START || vector > NR_MAX_VECTOR) {
 		pr_err("vioapic_process_eoi: invalid vector %u", vector);
 	}
 
diff --git a/hypervisor/arch/x86/ioapic.c b/hypervisor/arch/x86/ioapic.c
index 6a22ddc7c..954905b6c 100644
--- a/hypervisor/arch/x86/ioapic.c
+++ b/hypervisor/arch/x86/ioapic.c
@@ -372,7 +372,7 @@ void setup_ioapic_irq(void)
 			 * for legacy irq, reserved vector and never free
 			 */
 			if (gsi < NR_LEGACY_IRQ) {
-				vr = irq_desc_alloc_vector(gsi, false);
+				vr = irq_desc_alloc_vector(gsi);
 				if (vr > NR_MAX_VECTOR) {
 					pr_err("failed to alloc VR");
 					gsi++;
diff --git a/hypervisor/arch/x86/irq.c b/hypervisor/arch/x86/irq.c
index 14a629f70..d48e15e79 100644
--- a/hypervisor/arch/x86/irq.c
+++ b/hypervisor/arch/x86/irq.c
@@ -31,24 +31,14 @@ static void init_irq_desc(void)
 }
 
 /*
- * alloc vector 0x20-0xDF for irq
- *	lowpri:  0x20-0x7F
- *	highpri: 0x80-0xDF
+ * find available vector VECTOR_DYNAMIC_START ~ VECTOR_DYNAMIC_END
  */
-static uint32_t find_available_vector(bool lowpri)
+static uint32_t find_available_vector()
 {
-	uint32_t i, start, end;
-
-	if (lowpri) {
-		start = VECTOR_FOR_NOR_LOWPRI_START;
-		end = VECTOR_FOR_NOR_LOWPRI_END;
-	} else {
-		start = VECTOR_FOR_NOR_HIGHPRI_START;
-		end = VECTOR_FOR_NOR_HIGHPRI_END;
-	}
+	uint32_t i;
 
 	/* TODO: vector lock required */
-	for (i = start; i < end; i++) {
+	for (i = VECTOR_DYNAMIC_START; i <= VECTOR_DYNAMIC_END; i++) {
 		if (vector_to_irq[i] == IRQ_INVALID) {
 			return i;
 		}
@@ -269,11 +259,11 @@ common_register_handler(uint32_t irq_arg,
 OUT:
 	if (added) {
 		/* it is safe to call irq_desc_alloc_vector multiple times*/
-		if (info->vector >= VECTOR_FOR_PRI_START &&
-			info->vector <= VECTOR_FOR_PRI_END) {
+		if (info->vector >= VECTOR_FIXED_START &&
+			info->vector <= VECTOR_FIXED_END) {
 			irq_desc_set_vector(irq, info->vector);
 		} else if (info->vector > NR_MAX_VECTOR) {
-			irq_desc_alloc_vector(irq, info->lowpri);
+			irq_desc_alloc_vector(irq);
 		} else {
 			pr_err("the input vector is not correct");
 			free(node);
@@ -296,7 +286,7 @@ OUT:
 }
 
 /* it is safe to call irq_desc_alloc_vector multiple times*/
-uint32_t irq_desc_alloc_vector(uint32_t irq, bool lowpri)
+uint32_t irq_desc_alloc_vector(uint32_t irq)
 {
 	uint32_t vr = VECTOR_INVALID;
 	struct irq_desc *desc;
@@ -316,7 +306,7 @@ uint32_t irq_desc_alloc_vector(uint32_t irq, bool lowpri)
 	}
 
 	/* FLAT mode, a irq connected to every cpu's same vector */
-	vr = find_available_vector(lowpri);
+	vr = find_available_vector();
 	if (vr > NR_MAX_VECTOR) {
 		pr_err("no vector found for irq[%d]", irq);
 		goto OUT;
@@ -634,20 +624,18 @@ UNLOCK_EXIT:
 }
 
 /*
- * Allocate IRQ with Vector from 0x20 ~ 0xDF
+ * Allocate IRQ with Vector from VECTOR_DYNAMIC_START ~ VECTOR_DYNAMIC_END
  */
 struct dev_handler_node*
 normal_register_handler(uint32_t irq,
 		dev_handler_t func,
 		void *dev_data,
 		bool share,
-		bool lowpri,
 		const char *name)
 {
 	struct irq_request_info info;
 
 	info.vector = VECTOR_INVALID;
-	info.lowpri = lowpri;
 	info.func = func;
 	info.dev_data = dev_data;
 	info.share = share;
@@ -657,7 +645,7 @@ normal_register_handler(uint32_t irq,
 }
 
 /*
- * Allocate IRQ with vector from 0xE0 ~ 0xFF
+ * Allocate IRQ with vector from VECTOR_FIXED_START ~ VECTOR_FIXED_END
  * Allocate a IRQ and install isr on that specific cpu
  * User can install same irq/isr on different CPU by call this function multiple
  * times
@@ -671,12 +659,11 @@ pri_register_handler(uint32_t irq,
 {
 	struct irq_request_info info;
 
-	if (vector < VECTOR_FOR_PRI_START || vector > VECTOR_FOR_PRI_END) {
+	if (vector < VECTOR_FIXED_START || vector > VECTOR_FIXED_END) {
 		return NULL;
 	}
 
 	info.vector = vector;
-	info.lowpri = false;
 	info.func = func;
 	info.dev_data = dev_data;
 	info.share = true;
diff --git a/hypervisor/arch/x86/vtd.c b/hypervisor/arch/x86/vtd.c
index 62387fa15..f3fb8df4e 100644
--- a/hypervisor/arch/x86/vtd.c
+++ b/hypervisor/arch/x86/vtd.c
@@ -827,7 +827,7 @@ static int dmar_setup_interrupt(struct dmar_drhd_rt *dmar_uint)
 
 	dmar_uint->dmar_irq_node = normal_register_handler(IRQ_INVALID,
 					dmar_fault_handler,
-					dmar_uint, true, false,
+					dmar_uint, true,
 					"dmar_fault_event");
 
 	if (dmar_uint->dmar_irq_node == NULL) {
diff --git a/hypervisor/common/ptdev.c b/hypervisor/common/ptdev.c
index 274c2d6b8..a10381796 100644
--- a/hypervisor/common/ptdev.c
+++ b/hypervisor/common/ptdev.c
@@ -129,14 +129,13 @@ static int ptdev_interrupt_handler(__unused int irq, void *data)
 
 /* active intr with irq registering */
 void
-ptdev_activate_entry(struct ptdev_remapping_info *entry, uint32_t phys_irq,
-		bool lowpri)
+ptdev_activate_entry(struct ptdev_remapping_info *entry, uint32_t phys_irq)
 {
 	struct dev_handler_node *node;
 
 	/* register and allocate host vector/irq */
 	node = normal_register_handler(phys_irq, ptdev_interrupt_handler,
-		(void *)entry, true, lowpri, "dev assign");
+		(void *)entry, true, "dev assign");
 
 	ASSERT(node != NULL, "dev register failed");
 	entry->node = node;
diff --git a/hypervisor/include/arch/x86/irq.h b/hypervisor/include/arch/x86/irq.h
index fd8bba655..ac5ee6184 100644
--- a/hypervisor/include/arch/x86/irq.h
+++ b/hypervisor/include/arch/x86/irq.h
@@ -9,18 +9,14 @@
 
 #include <common/irq.h>
 
-/* vectors for normal, usually for devices */
-#define VECTOR_FOR_NOR_LOWPRI_START	0x20U
-#define VECTOR_FOR_NOR_LOWPRI_END	0x7FU
-#define VECTOR_FOR_NOR_HIGHPRI_START	0x80U
-#define VECTOR_FOR_NOR_HIGHPRI_END	0xDFU
-#define VECTOR_FOR_NOR_END		VECTOR_FOR_NOR_HIGHPRI_END
+/* vectors range for dynamic allocation, usually for devices */
+#define VECTOR_DYNAMIC_START	0x20U
+#define VECTOR_DYNAMIC_END	0xDFU
 
-#define VECTOR_FOR_INTR_START		VECTOR_FOR_NOR_LOWPRI_START
+/* vectors range for fixed vectors, usually for HV service */
+#define VECTOR_FIXED_START	0xE0U
+#define VECTOR_FIXED_END	0xFFU
 
-/* vectors for priority, usually for HV service */
-#define VECTOR_FOR_PRI_START	0xE0U
-#define VECTOR_FOR_PRI_END	0xFFU
 #define VECTOR_TIMER		0xEFU
 #define VECTOR_NOTIFY_VCPU	0xF0U
 #define VECTOR_VIRT_IRQ_VHM	0xF7U
diff --git a/hypervisor/include/common/irq.h b/hypervisor/include/common/irq.h
index 5537bfb01..5e9003f83 100644
--- a/hypervisor/include/common/irq.h
+++ b/hypervisor/include/common/irq.h
@@ -33,7 +33,6 @@ struct irq_request_info {
 	dev_handler_t func;
 	void *dev_data;
 	bool share;
-	bool lowpri;
 	char *name;
 };
 
@@ -61,7 +60,7 @@ struct dev_handler_node {
 
 uint32_t irq_mark_used(uint32_t irq);
 
-uint32_t irq_desc_alloc_vector(uint32_t irq, bool lowpri);
+uint32_t irq_desc_alloc_vector(uint32_t irq);
 void irq_desc_try_free_vector(uint32_t irq);
 
 uint32_t irq_to_vector(uint32_t irq);
@@ -80,7 +79,6 @@ normal_register_handler(uint32_t irq,
 		dev_handler_t func,
 		void *dev_data,
 		bool share,
-		bool lowpri,
 		const char *name);
 void unregister_handler_common(struct dev_handler_node *node);
 
diff --git a/hypervisor/include/common/ptdev.h b/hypervisor/include/common/ptdev.h
index ac73c2d5e..39864c777 100644
--- a/hypervisor/include/common/ptdev.h
+++ b/hypervisor/include/common/ptdev.h
@@ -75,7 +75,7 @@ struct ptdev_remapping_info *alloc_entry(struct vm *vm,
 void release_entry(struct ptdev_remapping_info *entry);
 void ptdev_activate_entry(
 		struct ptdev_remapping_info *entry,
-		uint32_t phys_irq, bool lowpri);
+		uint32_t phys_irq);
 void ptdev_deactivate_entry(struct ptdev_remapping_info *entry);
 
 #ifdef HV_DEBUG