[Qemu-devel] [PATCH qemu v16 02/19] memory: Call region_del() callbacks on memory listener unregistering

[Alexey Kardashevskiy]

When a new memory listener is registered, listener_add_address_space()
is called and which in turn calls region_add() callbacks of memory regions.
However when unregistering the memory listener, it is just removed from
the listening chain and no region_del() is called.

This adds listener_del_address_space() and uses it in
memory_listener_unregister(). listener_add_address_space() was used as
a template with the following changes:
s/log_global_start/log_global_stop/
s/log_start/log_stop/
s/region_add/region_del/

This will allow the following patches to add/remove DMA windows
dynamically from VFIO's PCI address space's region_add()/region_del().

Signed-off-by: Alexey Kardashevskiy <a...@ozlabs.ru>
---
 memory.c | 48 ++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 48 insertions(+)

diff --git a/memory.c b/memory.c
index f76f85d..f762a34 100644
--- a/memory.c
+++ b/memory.c
@@ -2185,6 +2185,49 @@ static void listener_add_address_space(MemoryListener 
*listener,
     flatview_unref(view);
 }
 
+static void listener_del_address_space(MemoryListener *listener,
+                                       AddressSpace *as)
+{
+    FlatView *view;
+    FlatRange *fr;
+
+    if (listener->address_space_filter
+        && listener->address_space_filter != as) {
+        return;
+    }
+
+    if (listener->begin) {
+        listener->begin(listener);
+    }
+    if (global_dirty_log) {
+        if (listener->log_global_stop) {
+            listener->log_global_stop(listener);
+        }
+    }
+
+    view = address_space_get_flatview(as);
+    FOR_EACH_FLAT_RANGE(fr, view) {
+        MemoryRegionSection section = {
+            .mr = fr->mr,
+            .address_space = as,
+            .offset_within_region = fr->offset_in_region,
+            .size = fr->addr.size,
+            .offset_within_address_space = int128_get64(fr->addr.start),
+            .readonly = fr->readonly,
+        };
+        if (fr->dirty_log_mask && listener->log_stop) {
+            listener->log_stop(listener, &section, 0, fr->dirty_log_mask);
+        }
+        if (listener->region_del) {
+            listener->region_del(listener, &section);
+        }
+    }
+    if (listener->commit) {
+        listener->commit(listener);
+    }
+    flatview_unref(view);
+}
+
 void memory_listener_register(MemoryListener *listener, AddressSpace *filter)
 {
     MemoryListener *other = NULL;
@@ -2211,6 +2254,11 @@ void memory_listener_register(MemoryListener *listener, 
AddressSpace *filter)
 
 void memory_listener_unregister(MemoryListener *listener)
 {
+    AddressSpace *as;
+
+    QTAILQ_FOREACH(as, &address_spaces, address_spaces_link) {
+        listener_del_address_space(listener, as);
+    }
     QTAILQ_REMOVE(&memory_listeners, listener, link);
 }
 
-- 
2.5.0.rc3