[Qemu-devel] [PATCH COLO-Frame v18 32/34] COLO/filter: Add each netdev a buffer filter

[zhanghailiang]

For COLO periodic mode, it needs to buffer packets that
sent by VM, and we will not release these packets until
finish a checkpoint.

Here, we add each netdev a buffer-filter that will be controlled
by COLO. It is off by default, and the packets will not pass
through these filters. If users don't enable COLO while configure
qemu, these buffer-filters will not be added.

Signed-off-by: zhanghailiang <address@hidden>
Cc: Jason Wang <address@hidden>
Cc: Yang Hongyang <address@hidden>
---
v16:
- Remove the useless check in colo_add_buffer_filter()
v15:
- call object_new_with_props() directly to add filter in
  colo_add_buffer_filter. (Jason's suggestion)
v14:
- New patch
---
 include/migration/colo.h |  3 +++
 include/net/filter.h     |  2 ++
 migration/colo-comm.c    |  7 +++++++
 migration/colo.c         | 39 +++++++++++++++++++++++++++++++++++++++
 net/filter-buffer.c      |  2 --
 stubs/migration-colo.c   |  4 ++++
 6 files changed, 55 insertions(+), 2 deletions(-)

diff --git a/include/migration/colo.h b/include/migration/colo.h
index b16c642..b08715a 100644
--- a/include/migration/colo.h
+++ b/include/migration/colo.h
@@ -37,4 +37,7 @@ COLOMode get_colo_mode(void);
 void colo_do_failover(MigrationState *s);
 
 bool colo_handle_shutdown(void);
+bool colo_shutdown(void);
+void colo_add_buffer_filter(Notifier *notifier, void *data);
+
 #endif
diff --git a/include/net/filter.h b/include/net/filter.h
index 0c4a2ea..817eaf4 100644
--- a/include/net/filter.h
+++ b/include/net/filter.h
@@ -21,6 +21,8 @@
 #define NETFILTER_CLASS(klass) \
     OBJECT_CLASS_CHECK(NetFilterClass, (klass), TYPE_NETFILTER)
 
+#define TYPE_FILTER_BUFFER "filter-buffer"
+
 typedef void (FilterSetup) (NetFilterState *nf, Error **errp);
 typedef void (FilterCleanup) (NetFilterState *nf);
 /*
diff --git a/migration/colo-comm.c b/migration/colo-comm.c
index 716a4f7..44ac76a 100644
--- a/migration/colo-comm.c
+++ b/migration/colo-comm.c
@@ -14,12 +14,14 @@
 #include "qemu/osdep.h"
 #include <migration/colo.h>
 #include "trace.h"
+#include <net/net.h>
 
 typedef struct {
      bool colo_requested;
 } COLOInfo;
 
 static COLOInfo colo_info;
+static Notifier netdev_init_notifier;
 
 COLOMode get_colo_mode(void)
 {
@@ -59,6 +61,11 @@ static const VMStateDescription colo_state = {
 void colo_info_init(void)
 {
     vmstate_register(NULL, 0, &colo_state, &colo_info);
+    /* FIXME: Remove this after COLO switch to using colo-proxy */
+    if (colo_supported()) {
+        netdev_init_notifier.notify = colo_add_buffer_filter;
+        netdev_register_init_notifier(&netdev_init_notifier);
+    }
 }
 
 bool migration_incoming_enable_colo(void)
diff --git a/migration/colo.c b/migration/colo.c
index f618ca6..9af48da 100644
--- a/migration/colo.c
+++ b/migration/colo.c
@@ -20,11 +20,22 @@
 #include "qapi/error.h"
 #include "migration/failover.h"
 #include "qapi-event.h"
+#include "net/net.h"
+#include "net/filter.h"
+#include "net/vhost_net.h"
 
 static bool vmstate_loading;
 
 #define COLO_BUFFER_BASE_SIZE (4 * 1024 * 1024)
 
+typedef struct COLOListNode {
+    void *opaque;
+    QLIST_ENTRY(COLOListNode) node;
+} COLOListNode;
+
+static QLIST_HEAD(, COLOListNode) COLOBufferFilters =
+    QLIST_HEAD_INITIALIZER(COLOBufferFilters);
+
 bool colo_supported(void)
 {
     return true;
@@ -378,6 +389,34 @@ static int colo_prepare_before_save(MigrationState *s)
     return ret;
 }
 
+void colo_add_buffer_filter(Notifier *notifier, void *data)
+{
+    char *netdev_id = data;
+    NetFilterState *nf;
+    char filter_name[128];
+    Object *filter;
+    COLOListNode *filternode;
+
+    snprintf(filter_name, sizeof(filter_name),
+            "%scolo", netdev_id);
+
+    filter = object_new_with_props(TYPE_FILTER_BUFFER,
+                        object_get_objects_root(),
+                        filter_name, NULL,
+                        "netdev", netdev_id,
+                        "status", "off",
+                        NULL);
+    if (!filter) {
+        return;
+    }
+    nf =  NETFILTER(filter);
+    /* Only buffer the packets that sent out by VM */
+    nf->direction = NET_FILTER_DIRECTION_RX;
+    filternode = g_new0(COLOListNode, 1);
+    filternode->opaque = nf;
+    QLIST_INSERT_HEAD(&COLOBufferFilters, filternode, node);
+}
+
 static void colo_process_checkpoint(MigrationState *s)
 {
     QIOChannelBuffer *bioc;
diff --git a/net/filter-buffer.c b/net/filter-buffer.c
index 346306a..d1cf595 100644
--- a/net/filter-buffer.c
+++ b/net/filter-buffer.c
@@ -17,8 +17,6 @@
 #include "qapi-visit.h"
 #include "qom/object.h"
 
-#define TYPE_FILTER_BUFFER "filter-buffer"
-
 #define FILTER_BUFFER(obj) \
     OBJECT_CHECK(FilterBufferState, (obj), TYPE_FILTER_BUFFER)
 
diff --git a/stubs/migration-colo.c b/stubs/migration-colo.c
index 167b191..ae29d47 100644
--- a/stubs/migration-colo.c
+++ b/stubs/migration-colo.c
@@ -49,3 +49,7 @@ bool colo_handle_shutdown(void)
 {
     return false;
 }
+
+void colo_add_buffer_filter(Notifier *notifier, void *data)
+{
+}
-- 
1.8.3.1