diff --git a/hw/vfio/common.c b/hw/vfio/common.c
index 0cacc66c85..49e3543c89 100644
--- a/hw/vfio/common.c
+++ b/hw/vfio/common.c
@@ -324,7 +324,7 @@ static void vfio_iommu_map_notify(IOMMUNotifier *n, IOMMUTLBEntry *iotlb)
         }
     } else {
         ret = vfio_container_dma_unmap(bcontainer, iova,
-                                       iotlb->addr_mask + 1, iotlb);
+                                       iotlb->addr_mask + 1, iotlb, 0);
         if (ret) {
             error_report("vfio_container_dma_unmap(%p, 0x%"HWADDR_PRIx", "
                          "0x%"HWADDR_PRIx") = %d (%s)",
@@ -348,7 +348,7 @@ static void vfio_ram_discard_notify_discard(RamDiscardListener *rdl,
     int ret;
 
     /* Unmap with a single call. */
-    ret = vfio_container_dma_unmap(bcontainer, iova, size , NULL);
+    ret = vfio_container_dma_unmap(bcontainer, iova, size, NULL, 0);
     if (ret) {
         error_report("%s: vfio_container_dma_unmap() failed: %s", __func__,
                      strerror(-ret));
@@ -789,21 +789,15 @@ static void vfio_listener_region_del(MemoryListener *listener,
     }
 
     if (try_unmap) {
+        int flags = 0;
+
         if (int128_eq(llsize, int128_2_64())) {
-            /* The unmap ioctl doesn't accept a full 64-bit span. */
-            llsize = int128_rshift(llsize, 1);
-            ret = vfio_container_dma_unmap(bcontainer, iova,
-                                           int128_get64(llsize), NULL);
-            if (ret) {
-                error_report("vfio_container_dma_unmap(%p, 0x%"HWADDR_PRIx", "
-                             "0x%"HWADDR_PRIx") = %d (%s)",
-                             bcontainer, iova, int128_get64(llsize), ret,
-                             strerror(-ret));
-            }
-            iova += int128_get64(llsize);
+            flags = VFIO_DMA_UNMAP_FLAG_ALL;
         }
-        ret = vfio_container_dma_unmap(bcontainer, iova,
-                                       int128_get64(llsize), NULL);
+
+        ret = vfio_container_dma_unmap(bcontainer, iova, int128_get64(llsize),
+                                       NULL, flags);
+
         if (ret) {
             error_report("vfio_container_dma_unmap(%p, 0x%"HWADDR_PRIx", "
                          "0x%"HWADDR_PRIx") = %d (%s)",
diff --git a/hw/vfio/container-base.c b/hw/vfio/container-base.c
index 5e0c9700d9..db27e9c31d 100644
--- a/hw/vfio/container-base.c
+++ b/hw/vfio/container-base.c
@@ -27,12 +27,12 @@ int vfio_container_dma_map(VFIOContainerBase *bcontainer,
 
 int vfio_container_dma_unmap(VFIOContainerBase *bcontainer,
                              hwaddr iova, ram_addr_t size,
-                             IOMMUTLBEntry *iotlb)
+                             IOMMUTLBEntry *iotlb, int flags)
 {
     VFIOIOMMUClass *vioc = VFIO_IOMMU_GET_CLASS(bcontainer);
 
     g_assert(vioc->dma_unmap);
-    return vioc->dma_unmap(bcontainer, iova, size, iotlb);
+    return vioc->dma_unmap(bcontainer, iova, size, iotlb, flags);
 }
 
 bool vfio_container_add_section_window(VFIOContainerBase *bcontainer,
diff --git a/hw/vfio/container.c b/hw/vfio/container.c
index fe193ac7da..39c77d402c 100644
--- a/hw/vfio/container.c
+++ b/hw/vfio/container.c
@@ -117,7 +117,7 @@ unmap_exit:
  */
 static int vfio_legacy_dma_unmap(const VFIOContainerBase *bcontainer,
                                  hwaddr iova, ram_addr_t size,
-                                 IOMMUTLBEntry *iotlb)
+                                 IOMMUTLBEntry *iotlb, int flags)
 {
     const VFIOContainer *container = container_of(bcontainer, VFIOContainer,
                                                   bcontainer);
@@ -140,6 +140,34 @@ static int vfio_legacy_dma_unmap(const VFIOContainerBase *bcontainer,
         need_dirty_sync = true;
     }
 
+    /* use unmap all if supported */
+    if (flags & VFIO_DMA_UNMAP_FLAG_ALL) {
+        unmap.iova = 0;
+        unmap.size = 0;
+        if (container->unmap_all_supported) {
+            ret = ioctl(container->fd, VFIO_IOMMU_UNMAP_DMA, unmap);
+        } else {
+            /* unmap in halves */
+            Int128 llsize = int128_rshift(int128_2_64(), 1);
+
+            unmap.size = int128_get64(llsize);
+
+            ret = ioctl(container->fd, VFIO_IOMMU_UNMAP_DMA, unmap);
+
+            if (ret == 0) {
+                unmap.iova += int128_get64(llsize);
+
+                ret = ioctl(container->fd, VFIO_IOMMU_UNMAP_DMA, unmap);
+            }
+        }
+
+        if (ret != 0) {
+            return -errno;
+        }
+
+        goto out;
+    }
+
     while (ioctl(container->fd, VFIO_IOMMU_UNMAP_DMA, &unmap)) {
         /*
          * The type1 backend has an off-by-one bug in the kernel (71a7d3d78e3c
@@ -163,6 +191,7 @@ static int vfio_legacy_dma_unmap(const VFIOContainerBase *bcontainer,
         return -errno;
     }
 
+out:
     if (need_dirty_sync) {
         ret = vfio_get_dirty_bitmap(bcontainer, iova, size,
                                     iotlb->translated_addr, &local_err);
@@ -200,7 +229,7 @@ static int vfio_legacy_dma_map(const VFIOContainerBase *bcontainer, hwaddr iova,
      */
     if (ioctl(container->fd, VFIO_IOMMU_MAP_DMA, &map) == 0 ||
         (errno == EBUSY &&
-         vfio_legacy_dma_unmap(bcontainer, iova, size, NULL) == 0 &&
+         vfio_legacy_dma_unmap(bcontainer, iova, size, NULL, 0) == 0 &&
          ioctl(container->fd, VFIO_IOMMU_MAP_DMA, &map) == 0)) {
         return 0;
     }
@@ -535,6 +564,11 @@ static bool vfio_legacy_setup(VFIOContainerBase *bcontainer, Error **errp)
     vfio_get_info_iova_range(info, bcontainer);
 
     vfio_get_iommu_info_migration(container, info);
+
+    ret = ioctl(container->fd, VFIO_CHECK_EXTENSION, VFIO_UNMAP_ALL);
+
+    container->unmap_all_supported = (ret != 0);
+
     return true;
 }
 
diff --git a/hw/vfio/iommufd.c b/hw/vfio/iommufd.c
index f541b00785..39c2b802b0 100644
--- a/hw/vfio/iommufd.c
+++ b/hw/vfio/iommufd.c
@@ -41,11 +41,28 @@ static int iommufd_cdev_map(const VFIOContainerBase *bcontainer, hwaddr iova,
 
 static int iommufd_cdev_unmap(const VFIOContainerBase *bcontainer,
                               hwaddr iova, ram_addr_t size,
-                              IOMMUTLBEntry *iotlb)
+                              IOMMUTLBEntry *iotlb, int flags)
 {
     const VFIOIOMMUFDContainer *container =
         container_of(bcontainer, VFIOIOMMUFDContainer, bcontainer);
 
+    /* unmap in halves */
+    if (flags & VFIO_DMA_UNMAP_FLAG_ALL) {
+        Int128 llsize = int128_rshift(int128_2_64(), 1);
+        int ret;
+
+        ret = iommufd_backend_unmap_dma(container->be, container->ioas_id,
+                                        iova, int128_get64(llsize));
+        iova += int128_get64(llsize);
+
+        if (ret == 0) {
+            ret = iommufd_backend_unmap_dma(container->be, container->ioas_id,
+                                            iova, int128_get64(llsize));
+        }
+
+        return ret;
+    }
+
     /* TODO: Handle dma_unmap_bitmap with iotlb args (migration) */
     return iommufd_backend_unmap_dma(container->be,
                                      container->ioas_id, iova, size);
diff --git a/include/hw/vfio/vfio-common.h b/include/hw/vfio/vfio-common.h
index 0c60be5b15..13c67d25cb 100644
--- a/include/hw/vfio/vfio-common.h
+++ b/include/hw/vfio/vfio-common.h
@@ -84,6 +84,7 @@ typedef struct VFIOContainer {
     VFIOContainerBase bcontainer;
     int fd; /* /dev/vfio/vfio, empowered by the attached groups */
     unsigned iommu_type;
+    bool unmap_all_supported;
     QLIST_HEAD(, VFIOGroup) group_list;
 } VFIOContainer;
 
diff --git a/include/hw/vfio/vfio-container-base.h b/include/hw/vfio/vfio-container-base.h
index 0a863df0dc..24e48e3a07 100644
--- a/include/hw/vfio/vfio-container-base.h
+++ b/include/hw/vfio/vfio-container-base.h
@@ -76,7 +76,7 @@ int vfio_container_dma_map(VFIOContainerBase *bcontainer,
                            void *vaddr, bool readonly, MemoryRegion *mrp);
 int vfio_container_dma_unmap(VFIOContainerBase *bcontainer,
                              hwaddr iova, ram_addr_t size,
-                             IOMMUTLBEntry *iotlb);
+                             IOMMUTLBEntry *iotlb, int flags);
 bool vfio_container_add_section_window(VFIOContainerBase *bcontainer,
                                        MemoryRegionSection *section,
                                        Error **errp);
@@ -118,7 +118,7 @@ struct VFIOIOMMUClass {
                    void *vaddr, bool readonly, MemoryRegion *mrp);
     int (*dma_unmap)(const VFIOContainerBase *bcontainer,
                      hwaddr iova, ram_addr_t size,
-                     IOMMUTLBEntry *iotlb);
+                     IOMMUTLBEntry *iotlb, int flags);
     bool (*attach_device)(const char *name, VFIODevice *vbasedev,
                           AddressSpace *as, Error **errp);
     void (*detach_device)(VFIODevice *vbasedev);
