diff --git a/hw/i386/intel_iommu.c b/hw/i386/intel_iommu.c
index 17668d6..00b873c 100644
--- a/hw/i386/intel_iommu.c
+++ b/hw/i386/intel_iommu.c
@@ -30,7 +30,7 @@
 #ifdef DEBUG_INTEL_IOMMU
 enum {
     DEBUG_GENERAL, DEBUG_CSR, DEBUG_INV, DEBUG_MMU, DEBUG_FLOG,
-    DEBUG_CACHE,
+    DEBUG_CACHE, DEBUG_IR,
 };
 #define VTD_DBGBIT(x)   (1 << DEBUG_##x)
 static int vtd_dbgflags = VTD_DBGBIT(GENERAL) | VTD_DBGBIT(CSR);
@@ -900,6 +900,19 @@ static void vtd_root_table_setup(IntelIOMMUState *s)
                 (s->root_extended ? "(extended)" : ""));
 }
 
+static void vtd_interrupt_remap_table_setup(IntelIOMMUState *s)
+{
+    uint64_t value = 0;
+    value = vtd_get_quad_raw(s, DMAR_IRTA_REG);
+    s->intr_size = 1UL << ((value & VTD_IRTA_SIZE_MASK) + 1);
+    s->intr_root = value & VTD_IRTA_ADDR_MASK;
+
+    /* TODO: invalidate interrupt entry cache */
+
+    VTD_DPRINTF(CSR, "int remap table addr 0x%"PRIx64 " size %"PRIu32,
+                s->intr_root, s->intr_size);
+}
+
 static void vtd_context_global_invalidate(IntelIOMMUState *s)
 {
     s->context_cache_gen++;
@@ -1138,6 +1151,16 @@ static void vtd_handle_gcmd_srtp(IntelIOMMUState *s)
     vtd_set_clear_mask_long(s, DMAR_GSTS_REG, 0, VTD_GSTS_RTPS);
 }
 
+/* Set Interrupt Remap Table Pointer */
+static void vtd_handle_gcmd_sirtp(IntelIOMMUState *s)
+{
+    VTD_DPRINTF(CSR, "set Interrupt Remap Table Pointer");
+
+    vtd_interrupt_remap_table_setup(s);
+    /* Ok - report back to driver */
+    vtd_set_clear_mask_long(s, DMAR_GSTS_REG, 0, VTD_GSTS_IRTPS);
+}
+
 /* Handle Translation Enable/Disable */
 static void vtd_handle_gcmd_te(IntelIOMMUState *s, bool en)
 {
@@ -1177,6 +1200,10 @@ static void vtd_handle_gcmd_write(IntelIOMMUState *s)
         /* Queued Invalidation Enable */
         vtd_handle_gcmd_qie(s, val & VTD_GCMD_QIE);
     }
+    if (val & VTD_GCMD_SIRTP) {
+        /* Set/update the interrupt remapping root-table pointer */
+        vtd_handle_gcmd_sirtp(s);
+    }
 }
 
 /* Handle write to Context Command Register */
@@ -1838,6 +1865,23 @@ static void vtd_mem_write(void *opaque, hwaddr addr,
         vtd_update_fsts_ppf(s);
         break;
 
+    case DMAR_IRTA_REG:
+        VTD_DPRINTF(IR, "DMAR_IRTA_REG write addr 0x%"PRIx64
+                    ", size %d, val 0x%"PRIx64, addr, size, val);
+        if (size == 4) {
+            vtd_set_long(s, addr, val);
+        } else {
+            vtd_set_quad(s, addr, val);
+        }
+        break;
+
+    case DMAR_IRTA_REG_HI:
+        VTD_DPRINTF(IR, "DMAR_IRTA_REG_HI write addr 0x%"PRIx64
+                    ", size %d, val 0x%"PRIx64, addr, size, val);
+        assert(size == 4);
+        vtd_set_long(s, addr, val);
+        break;
+
     default:
         VTD_DPRINTF(GENERAL, "error: unhandled reg write addr 0x%"PRIx64
                     ", size %d, val 0x%"PRIx64, addr, size, val);
@@ -2017,6 +2061,12 @@ static void vtd_init(IntelIOMMUState *s)
     /* Fault Recording Registers, 128-bit */
     vtd_define_quad(s, DMAR_FRCD_REG_0_0, 0, 0, 0);
     vtd_define_quad(s, DMAR_FRCD_REG_0_2, 0, 0, 0x8000000000000000ULL);
+
+    /*
+     * Interrupt remapping registers, not support extended interrupt
+     * mode for now.
+     */
+    vtd_define_quad(s, DMAR_IRTA_REG, 0, 0xfffffffffffff00fULL, 0);
 }
 
 /* Should not reset address_spaces when reset because devices will still use
diff --git a/hw/i386/intel_iommu_internal.h b/hw/i386/intel_iommu_internal.h
index 5b98a11..309833f 100644
--- a/hw/i386/intel_iommu_internal.h
+++ b/hw/i386/intel_iommu_internal.h
@@ -172,6 +172,10 @@
 #define VTD_RTADDR_RTT              (1ULL << 11)
 #define VTD_RTADDR_ADDR_MASK        (VTD_HAW_MASK ^ 0xfffULL)
 
+/* IRTA_REG */
+#define VTD_IRTA_ADDR_MASK          (VTD_HAW_MASK ^ 0xfffULL)
+#define VTD_IRTA_SIZE_MASK          (0xfULL)
+
 /* ECAP_REG */
 /* (offset >> 4) << 8 */
 #define VTD_ECAP_IRO                (DMAR_IOTLB_REG_OFFSET << 4)
diff --git a/include/hw/i386/intel_iommu.h b/include/hw/i386/intel_iommu.h
index 0d89796..cc49839 100644
--- a/include/hw/i386/intel_iommu.h
+++ b/include/hw/i386/intel_iommu.h
@@ -125,6 +125,11 @@ struct IntelIOMMUState {
     MemoryRegionIOMMUOps iommu_ops;
     GHashTable *vtd_as_by_busptr;   /* VTDBus objects indexed by PCIBus* reference */
     VTDBus *vtd_as_by_bus_num[VTD_PCI_BUS_MAX]; /* VTDBus objects indexed by bus number */
+
+    /* interrupt remapping */
+    bool intr_enabled;              /* Whether guest enabled IR */
+    dma_addr_t intr_root;           /* Interrupt remapping table pointer */
+    uint32_t intr_size;             /* Number of IR table entries */
 };
 
 /* Find the VTD Address space associated with the given bus pointer,
