Callers can use this function to setup the incoming migration.

Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
---
 include/hw/virtio/vhost-vdpa.h |  7 +++++++
 hw/virtio/vhost-vdpa.c         | 17 ++++++++++++++++-
 2 files changed, 23 insertions(+), 1 deletion(-)

diff --git a/include/hw/virtio/vhost-vdpa.h b/include/hw/virtio/vhost-vdpa.h
index 8f54e5edd4..edc08b7a02 100644
--- a/include/hw/virtio/vhost-vdpa.h
+++ b/include/hw/virtio/vhost-vdpa.h
@@ -45,6 +45,12 @@ typedef struct vhost_vdpa_shared {
 
     bool iotlb_batch_begin_sent;
 
+    /*
+     * The memory listener has been registered, so DMA maps have been sent to
+     * the device.
+     */
+    bool listener_registered;
+
     /* Vdpa must send shadow addresses as IOTLB key for data queues, not GPA */
     bool shadow_data;
 } VhostVDPAShared;
@@ -73,6 +79,7 @@ int vhost_vdpa_dma_map(VhostVDPAShared *s, uint32_t asid, hwaddr iova,
                        hwaddr size, void *vaddr, bool readonly);
 int vhost_vdpa_dma_unmap(VhostVDPAShared *s, uint32_t asid, hwaddr iova,
                          hwaddr size);
+int vhost_vdpa_load_setup(VhostVDPAShared *s, AddressSpace *dma_as);
 
 typedef struct vdpa_iommu {
     VhostVDPAShared *dev_shared;
diff --git a/hw/virtio/vhost-vdpa.c b/hw/virtio/vhost-vdpa.c
index cc252fc2d8..bfbe4673af 100644
--- a/hw/virtio/vhost-vdpa.c
+++ b/hw/virtio/vhost-vdpa.c
@@ -1325,7 +1325,9 @@ static int vhost_vdpa_dev_start(struct vhost_dev *dev, bool started)
                          "IOMMU and try again");
             return -1;
         }
-        memory_listener_register(&v->shared->listener, dev->vdev->dma_as);
+        if (!v->shared->listener_registered) {
+            memory_listener_register(&v->shared->listener, dev->vdev->dma_as);
+        }
 
         return vhost_vdpa_add_status(dev, VIRTIO_CONFIG_S_DRIVER_OK);
     }
@@ -1528,3 +1530,16 @@ const VhostOps vdpa_ops = {
         .vhost_set_config_call = vhost_vdpa_set_config_call,
         .vhost_reset_status = vhost_vdpa_reset_status,
 };
+
+int vhost_vdpa_load_setup(VhostVDPAShared *shared, AddressSpace *dma_as)
+{
+    uint8_t s = VIRTIO_CONFIG_S_ACKNOWLEDGE | VIRTIO_CONFIG_S_DRIVER;
+    int r = ioctl(shared->device_fd, VHOST_VDPA_SET_STATUS, &s);
+    if (unlikely(r < 0)) {
+        return r;
+    }
+
+    memory_listener_register(&shared->listener, dma_as);
+    shared->listener_registered = true;
+    return 0;
+}
-- 
2.39.3