vfio: Introduce vfio_listener_un/register() routines

This hides the MemoryListener implementation and makes the code common
to both IOMMU backends, legacy and IOMMUFD.

Reviewed-by: Joao Martins <joao.m.martins@oracle.com>
Reviewed-by: John Levon <john.levon@nutanix.com>
Link: https://lore.kernel.org/qemu-devel/20250326075122.1299361-35-clg@redhat.com
Signed-off-by: Cédric Le Goater <clg@redhat.com>

4 files changed, 28 insertions, 17 deletions

diff --git a/hw/vfio/container.c b/hw/vfio/container.c
index ff540e1c59..e4fcb1ad8b 100644
--- a/hw/vfio/container.c
+++ b/hw/vfio/container.c
@@ -616,12 +616,7 @@ static bool vfio_connect_container(VFIOGroup *group, AddressSpace *as,
     group->container = container;
     QLIST_INSERT_HEAD(&container->group_list, group, container_next);
 
-    bcontainer->listener = vfio_memory_listener;
-    memory_listener_register(&bcontainer->listener, bcontainer->space->as);
-
-    if (bcontainer->error) {
-        error_propagate_prepend(errp, bcontainer->error,
-            "memory listener initialization failed: ");
+    if (!vfio_listener_register(bcontainer, errp)) {
         goto listener_release_exit;
     }
 
@@ -631,7 +626,7 @@ static bool vfio_connect_container(VFIOGroup *group, AddressSpace *as,
 listener_release_exit:
     QLIST_REMOVE(group, container_next);
     vfio_kvm_device_del_group(group);
-    memory_listener_unregister(&bcontainer->listener);
+    vfio_listener_unregister(bcontainer);
     if (vioc->release) {
         vioc->release(bcontainer);
     }
@@ -669,7 +664,7 @@ static void vfio_disconnect_container(VFIOGroup *group)
      * group.
      */
     if (QLIST_EMPTY(&container->group_list)) {
-        memory_listener_unregister(&bcontainer->listener);
+        vfio_listener_unregister(bcontainer);
         if (vioc->release) {
             vioc->release(bcontainer);
         }
diff --git a/hw/vfio/iommufd.c b/hw/vfio/iommufd.c
index 7488d21215..e47720247d 100644
--- a/hw/vfio/iommufd.c
+++ b/hw/vfio/iommufd.c
@@ -410,7 +410,7 @@ static void iommufd_cdev_container_destroy(VFIOIOMMUFDContainer *container)
     if (!QLIST_EMPTY(&bcontainer->device_list)) {
         return;
     }
-    memory_listener_unregister(&bcontainer->listener);
+    vfio_listener_unregister(bcontainer);
     iommufd_backend_free_id(container->be, container->ioas_id);
     object_unref(container);
 }
@@ -562,12 +562,7 @@ static bool iommufd_cdev_attach(const char *name, VFIODevice *vbasedev,
         bcontainer->pgsizes = qemu_real_host_page_size();
     }
 
-    bcontainer->listener = vfio_memory_listener;
-    memory_listener_register(&bcontainer->listener, bcontainer->space->as);
-
-    if (bcontainer->error) {
-        error_propagate_prepend(errp, bcontainer->error,
-                                "memory listener initialization failed: ");
+    if (!vfio_listener_register(bcontainer, errp)) {
         goto err_listener_register;
     }
 
diff --git a/hw/vfio/listener.c b/hw/vfio/listener.c
index 70bdeb3ce7..d19674503c 100644
--- a/hw/vfio/listener.c
+++ b/hw/vfio/listener.c
@@ -45,6 +45,7 @@
 #include "system/tpm.h"
 #include "vfio-migration-internal.h"
 #include "vfio-helpers.h"
+#include "vfio-listener.h"
 
 /*
  * Device state interfaces
@@ -1162,7 +1163,7 @@ static void vfio_listener_log_sync(MemoryListener *listener,
     }
 }
 
-const MemoryListener vfio_memory_listener = {
+static const MemoryListener vfio_memory_listener = {
     .name = "vfio",
     .region_add = vfio_listener_region_add,
     .region_del = vfio_listener_region_del,
@@ -1170,3 +1171,22 @@ const MemoryListener vfio_memory_listener = {
     .log_global_stop = vfio_listener_log_global_stop,
     .log_sync = vfio_listener_log_sync,
 };
+
+bool vfio_listener_register(VFIOContainerBase *bcontainer, Error **errp)
+{
+    bcontainer->listener = vfio_memory_listener;
+    memory_listener_register(&bcontainer->listener, bcontainer->space->as);
+
+    if (bcontainer->error) {
+        error_propagate_prepend(errp, bcontainer->error,
+                                "memory listener initialization failed: ");
+        return false;
+    }
+
+    return true;
+}
+
+void vfio_listener_unregister(VFIOContainerBase *bcontainer)
+{
+    memory_listener_unregister(&bcontainer->listener);
+}
diff --git a/hw/vfio/vfio-listener.h b/hw/vfio/vfio-listener.h
index 93af6747b2..eb69ddd374 100644
--- a/hw/vfio/vfio-listener.h
+++ b/hw/vfio/vfio-listener.h
@@ -9,6 +9,7 @@
 #ifndef HW_VFIO_VFIO_LISTENER_H
 #define HW_VFIO_VFIO_LISTENER_H
 
-extern const MemoryListener vfio_memory_listener;
+bool vfio_listener_register(VFIOContainerBase *bcontainer, Error **errp);
+void vfio_listener_unregister(VFIOContainerBase *bcontainer);
 
 #endif /* HW_VFIO_VFIO_LISTENER_H */