diff --git a/hypervisor/arch/x86/vtd.c b/hypervisor/arch/x86/vtd.c
index 1d49c3030..f084a6bf3 100644
--- a/hypervisor/arch/x86/vtd.c
+++ b/hypervisor/arch/x86/vtd.c
@@ -205,7 +205,7 @@ static inline uint16_t vmid_to_domainid(uint16_t vm_id)
 }
 
 static int32_t dmar_register_hrhd(struct dmar_drhd_rt *dmar_unit);
-static struct dmar_drhd_rt *device_to_dmaru(uint16_t segment, uint8_t bus, uint8_t devfun);
+static struct dmar_drhd_rt *device_to_dmaru(uint8_t bus, uint8_t devfun);
 static int32_t register_hrhd_units(void)
 {
 	struct dmar_drhd_rt *drhd_rt;
@@ -553,7 +553,7 @@ static struct dmar_drhd_rt *ioapic_to_dmaru(uint16_t ioapic_id, union pci_bdf *s
 	return dmar_unit;
 }
 
-static struct dmar_drhd_rt *device_to_dmaru(uint16_t segment, uint8_t bus, uint8_t devfun)
+static struct dmar_drhd_rt *device_to_dmaru(uint8_t bus, uint8_t devfun)
 {
 	struct dmar_drhd_rt *dmar_unit = NULL;
 	uint32_t i, j;
@@ -561,10 +561,6 @@ static struct dmar_drhd_rt *device_to_dmaru(uint16_t segment, uint8_t bus, uint8
 	for (j = 0U; j < platform_dmar_info->drhd_count; j++) {
 		dmar_unit = &dmar_drhd_units[j];
 
-		if (dmar_unit->drhd->segment != segment) {
-			continue;
-		}
-
 		for (i = 0U; i < dmar_unit->drhd->dev_cnt; i++) {
 			if ((dmar_unit->drhd->devices[i].bus == bus) &&
 					(dmar_unit->drhd->devices[i].devfun == devfun)) {
@@ -572,7 +568,6 @@ static struct dmar_drhd_rt *device_to_dmaru(uint16_t segment, uint8_t bus, uint8
 			}
 		}
 
-		/* found exact one or the one which has the same segment number with INCLUDE_PCI_ALL set */
 		if ((i != dmar_unit->drhd->dev_cnt) || ((dmar_unit->drhd->flags & DRHD_FLAG_INCLUDE_PCI_ALL_MASK) != 0U)) {
 			break;
 		}
@@ -1049,7 +1044,7 @@ static void dmar_resume(struct dmar_drhd_rt *dmar_unit)
 	dmar_enable_intr_remapping(dmar_unit);
 }
 
-static int32_t add_iommu_device(struct iommu_domain *domain, uint16_t segment, uint8_t bus, uint8_t devfun)
+static int32_t add_iommu_device(struct iommu_domain *domain, uint8_t bus, uint8_t devfun)
 {
 	struct dmar_drhd_rt *dmar_unit;
 	struct dmar_entry *root_table;
@@ -1066,7 +1061,7 @@ static int32_t add_iommu_device(struct iommu_domain *domain, uint16_t segment, u
 	sid.fields.bus = bus;
 	sid.fields.devfun = devfun;
 
-	dmar_unit = device_to_dmaru(segment, bus, devfun);
+	dmar_unit = device_to_dmaru(bus, devfun);
 	if (dmar_unit == NULL) {
 		pr_err("no dmar unit found for device: %x:%x.%x", bus, sid.bits.d, sid.bits.f);
 		ret = -EINVAL;
@@ -1164,7 +1159,7 @@ static int32_t add_iommu_device(struct iommu_domain *domain, uint16_t segment, u
 	return ret;
 }
 
-static int32_t remove_iommu_device(const struct iommu_domain *domain, uint16_t segment, uint8_t bus, uint8_t devfun)
+static int32_t remove_iommu_device(const struct iommu_domain *domain, uint8_t bus, uint8_t devfun)
 {
 	struct dmar_drhd_rt *dmar_unit;
 	struct dmar_entry *root_table;
@@ -1176,7 +1171,7 @@ static int32_t remove_iommu_device(const struct iommu_domain *domain, uint16_t s
 	union pci_bdf sid;
 	int32_t ret = 0;
 
-	dmar_unit = device_to_dmaru(segment, bus, devfun);
+	dmar_unit = device_to_dmaru(bus, devfun);
 
 	sid.fields.bus = bus;
 	sid.fields.devfun = devfun;
@@ -1302,11 +1297,11 @@ int32_t move_pt_device(const struct iommu_domain *from_domain, struct iommu_doma
 
 	if (bus_local < CONFIG_IOMMU_BUS_NUM) {
 		if (from_domain != NULL) {
-			status = remove_iommu_device(from_domain, 0U, bus, devfun);
+			status = remove_iommu_device(from_domain, bus, devfun);
 		}
 
 		if ((status == 0) && (to_domain != NULL)) {
-			status = add_iommu_device(to_domain, 0U, bus, devfun);
+			status = add_iommu_device(to_domain, bus, devfun);
 		}
 	} else {
 		status = -EINVAL;
@@ -1373,7 +1368,7 @@ int32_t dmar_assign_irte(struct intr_source intr_src, union dmar_ir_entry irte,
 	int32_t ret = 0;
 
 	if (intr_src.is_msi) {
-		dmar_unit = device_to_dmaru(0U, (uint8_t)intr_src.src.msi.bits.b, intr_src.src.msi.fields.devfun);
+		dmar_unit = device_to_dmaru((uint8_t)intr_src.src.msi.bits.b, intr_src.src.msi.fields.devfun);
 		sid.value = intr_src.src.msi.value;
 		trigger_mode = 0x0UL;
 	} else {
@@ -1417,7 +1412,7 @@ void dmar_free_irte(struct intr_source intr_src, uint16_t index)
 	union pci_bdf sid;
 
 	if (intr_src.is_msi) {
-		dmar_unit = device_to_dmaru(0U, (uint8_t)intr_src.src.msi.bits.b, intr_src.src.msi.fields.devfun);
+		dmar_unit = device_to_dmaru((uint8_t)intr_src.src.msi.bits.b, intr_src.src.msi.fields.devfun);
 	} else {
 		dmar_unit = ioapic_to_dmaru(intr_src.src.ioapic_id, &sid);
 	}