diff --git a/hw/virtio/trace-events b/hw/virtio/trace-events
index 9270b0463e..4b15086872 100644
--- a/hw/virtio/trace-events
+++ b/hw/virtio/trace-events
@@ -61,3 +61,7 @@ virtio_iommu_map(uint32_t domain_id, uint64_t virt_start, uint64_t virt_end, uin
 virtio_iommu_unmap(uint32_t domain_id, uint64_t virt_start, uint64_t virt_end) "domain=%d virt_start=0x%"PRIx64" virt_end=0x%"PRIx64
 virtio_iommu_translate(const char *name, uint32_t rid, uint64_t iova, int flag) "mr=%s rid=%d addr=0x%"PRIx64" flag=%d"
 virtio_iommu_init_iommu_mr(char *iommu_mr) "init %s"
+virtio_iommu_get_endpoint(uint32_t ep_id) "Alloc endpoint=%d"
+virtio_iommu_put_endpoint(uint32_t ep_id) "Free endpoint=%d"
+virtio_iommu_get_domain(uint32_t domain_id) "Alloc domain=%d"
+virtio_iommu_put_domain(uint32_t domain_id) "Free domain=%d"
diff --git a/hw/virtio/virtio-iommu.c b/hw/virtio/virtio-iommu.c
index dead062baf..1b9c3ba416 100644
--- a/hw/virtio/virtio-iommu.c
+++ b/hw/virtio/virtio-iommu.c
@@ -33,20 +33,124 @@
 #include "hw/virtio/virtio-bus.h"
 #include "hw/virtio/virtio-access.h"
 #include "hw/virtio/virtio-iommu.h"
+#include "hw/pci/pci_bus.h"
+#include "hw/pci/pci.h"
 
 /* Max size */
 #define VIOMMU_DEFAULT_QUEUE_SIZE 256
 
+typedef struct viommu_domain {
+    uint32_t id;
+    GTree *mappings;
+    QLIST_HEAD(, viommu_endpoint) endpoint_list;
+} viommu_domain;
+
+typedef struct viommu_endpoint {
+    uint32_t id;
+    viommu_domain *domain;
+    QLIST_ENTRY(viommu_endpoint) next;
+    VirtIOIOMMU *viommu;
+} viommu_endpoint;
+
+typedef struct viommu_interval {
+    uint64_t low;
+    uint64_t high;
+} viommu_interval;
+
 static inline uint16_t virtio_iommu_get_sid(IOMMUDevice *dev)
 {
     return PCI_BUILD_BDF(pci_bus_num(dev->bus), dev->devfn);
 }
 
+static gint interval_cmp(gconstpointer a, gconstpointer b, gpointer user_data)
+{
+    viommu_interval *inta = (viommu_interval *)a;
+    viommu_interval *intb = (viommu_interval *)b;
+
+    if (inta->high <= intb->low) {
+        return -1;
+    } else if (intb->high <= inta->low) {
+        return 1;
+    } else {
+        return 0;
+    }
+}
+
+static void virtio_iommu_detach_endpoint_from_domain(viommu_endpoint *ep)
+{
+    QLIST_REMOVE(ep, next);
+    ep->domain = NULL;
+}
+
+viommu_endpoint *virtio_iommu_get_endpoint(VirtIOIOMMU *s, uint32_t ep_id);
+viommu_endpoint *virtio_iommu_get_endpoint(VirtIOIOMMU *s, uint32_t ep_id)
+{
+    viommu_endpoint *ep;
+
+    ep = g_tree_lookup(s->endpoints, GUINT_TO_POINTER(ep_id));
+    if (ep) {
+        return ep;
+    }
+    ep = g_malloc0(sizeof(*ep));
+    ep->id = ep_id;
+    ep->viommu = s;
+    trace_virtio_iommu_get_endpoint(ep_id);
+    g_tree_insert(s->endpoints, GUINT_TO_POINTER(ep_id), ep);
+    return ep;
+}
+
+static void virtio_iommu_put_endpoint(gpointer data)
+{
+    viommu_endpoint *ep = (viommu_endpoint *)data;
+
+    if (ep->domain) {
+        virtio_iommu_detach_endpoint_from_domain(ep);
+        g_tree_unref(ep->domain->mappings);
+    }
+
+    trace_virtio_iommu_put_endpoint(ep->id);
+    g_free(ep);
+}
+
+viommu_domain *virtio_iommu_get_domain(VirtIOIOMMU *s, uint32_t domain_id);
+viommu_domain *virtio_iommu_get_domain(VirtIOIOMMU *s, uint32_t domain_id)
+{
+    viommu_domain *domain;
+
+    domain = g_tree_lookup(s->domains, GUINT_TO_POINTER(domain_id));
+    if (domain) {
+        return domain;
+    }
+    domain = g_malloc0(sizeof(*domain));
+    domain->id = domain_id;
+    domain->mappings = g_tree_new_full((GCompareDataFunc)interval_cmp,
+                                   NULL, (GDestroyNotify)g_free,
+                                   (GDestroyNotify)g_free);
+    g_tree_insert(s->domains, GUINT_TO_POINTER(domain_id), domain);
+    QLIST_INIT(&domain->endpoint_list);
+    trace_virtio_iommu_get_domain(domain_id);
+    return domain;
+}
+
+static void virtio_iommu_put_domain(gpointer data)
+{
+    viommu_domain *domain = (viommu_domain *)data;
+    viommu_endpoint *iter, *tmp;
+
+    QLIST_FOREACH_SAFE(iter, &domain->endpoint_list, next, tmp) {
+        virtio_iommu_detach_endpoint_from_domain(iter);
+    }
+    g_tree_destroy(domain->mappings);
+    trace_virtio_iommu_put_domain(domain->id);
+    g_free(domain);
+}
+
 static AddressSpace *virtio_iommu_find_add_as(PCIBus *bus, void *opaque,
                                               int devfn)
 {
     VirtIOIOMMU *s = opaque;
     IOMMUPciBus *sbus = g_hash_table_lookup(s->as_by_busptr, bus);
+    static uint32_t mr_index;
     IOMMUDevice *sdev;
 
     if (!sbus) {
@@ -60,7 +164,7 @@ static AddressSpace *virtio_iommu_find_add_as(PCIBus *bus, void *opaque,
     if (!sdev) {
         char *name = g_strdup_printf("%s-%d-%d",
                                      TYPE_VIRTIO_IOMMU_MEMORY_REGION,
-                                     pci_bus_num(bus), devfn);
+                                     mr_index++, devfn);
         sdev = sbus->pbdev[devfn] = g_malloc0(sizeof(IOMMUDevice));
 
         sdev->viommu = s;
@@ -75,6 +179,7 @@ static AddressSpace *virtio_iommu_find_add_as(PCIBus *bus, void *opaque,
                                  UINT64_MAX);
         address_space_init(&sdev->as,
                            MEMORY_REGION(&sdev->iommu_mr), TYPE_VIRTIO_IOMMU);
+        g_free(name);
     }
 
     return &sdev->as;
@@ -332,6 +437,13 @@ static const VMStateDescription vmstate_virtio_iommu_device = {
     },
 };
 
+static gint int_cmp(gconstpointer a, gconstpointer b, gpointer user_data)
+{
+    uint ua = GPOINTER_TO_UINT(a);
+    uint ub = GPOINTER_TO_UINT(b);
+    return (ua > ub) - (ua < ub);
+}
+
 static void virtio_iommu_device_realize(DeviceState *dev, Error **errp)
 {
     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
@@ -356,6 +468,8 @@ static void virtio_iommu_device_realize(DeviceState *dev, Error **errp)
     virtio_add_feature(&s->features, VIRTIO_IOMMU_F_MAP_UNMAP);
     virtio_add_feature(&s->features, VIRTIO_IOMMU_F_BYPASS);
 
+    qemu_mutex_init(&s->mutex);
+
     memset(s->as_by_bus_num, 0, sizeof(s->as_by_bus_num));
     s->as_by_busptr = g_hash_table_new(NULL, NULL);
 
@@ -364,11 +478,20 @@ static void virtio_iommu_device_realize(DeviceState *dev, Error **errp)
     } else {
         error_setg(errp, "VIRTIO-IOMMU is not attached to any PCI bus!");
     }
+
+    s->domains = g_tree_new_full((GCompareDataFunc)int_cmp,
+                                 NULL, NULL, virtio_iommu_put_domain);
+    s->endpoints = g_tree_new_full((GCompareDataFunc)int_cmp,
+                                   NULL, NULL, virtio_iommu_put_endpoint);
 }
 
 static void virtio_iommu_device_unrealize(DeviceState *dev, Error **errp)
 {
     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
+    VirtIOIOMMU *s = VIRTIO_IOMMU(dev);
+
+    g_tree_destroy(s->domains);
+    g_tree_destroy(s->endpoints);
 
     virtio_cleanup(vdev);
 }
