[Qemu-devel] [PATCH COLO-Frame v15 34/38] COLO/filter: add each netdev a buffer filter

[zhanghailiang]

For COLO periodic mode, it need 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 disabled 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>
---
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 |  2 ++
 include/net/filter.h     |  2 ++
 migration/colo-comm.c    |  5 +++++
 migration/colo.c         | 49 ++++++++++++++++++++++++++++++++++++++++++++++++
 net/filter-buffer.c      |  2 --
 stubs/migration-colo.c   |  4 ++++
 6 files changed, 62 insertions(+), 2 deletions(-)

diff --git a/include/migration/colo.h b/include/migration/colo.h
index 919b135..22b92c9 100644
--- a/include/migration/colo.h
+++ b/include/migration/colo.h
@@ -37,4 +37,6 @@ COLOMode get_colo_mode(void);
 void colo_do_failover(MigrationState *s);
 
 bool colo_shutdown(void);
+void colo_add_buffer_filter(const char *netdev_id, void *opaque);
+
 #endif
diff --git a/include/net/filter.h b/include/net/filter.h
index af3c53c..faccedd 100644
--- a/include/net/filter.h
+++ b/include/net/filter.h
@@ -22,6 +22,8 @@
 #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 3943e94..91d873e 100644
--- a/migration/colo-comm.c
+++ b/migration/colo-comm.c
@@ -13,6 +13,7 @@
 
 #include <migration/colo.h>
 #include "trace.h"
+#include <net/net.h>
 
 typedef struct {
      bool colo_requested;
@@ -58,6 +59,10 @@ 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 use colo-proxy */
+    if (colo_supported()) {
+        netdev_init_add_handler(colo_add_buffer_filter, NULL);
+    }
 }
 
 bool migration_incoming_enable_colo(void)
diff --git a/migration/colo.c b/migration/colo.c
index 0140203..bbff4e8 100644
--- a/migration/colo.c
+++ b/migration/colo.c
@@ -18,12 +18,23 @@
 #include "qemu/error-report.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;
 
 /* colo buffer */
 #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;
@@ -382,6 +393,44 @@ static int colo_prepare_before_save(MigrationState *s)
     return ret;
 }
 
+void colo_add_buffer_filter(const char *netdev_id, void *opaque)
+{
+    NetFilterState *nf;
+    char filter_name[128];
+    Object *filter;
+    COLOListNode *filternode;
+    NetClientState *nc = qemu_find_netdev(netdev_id);
+
+    /* FIXME: Not support multiple queues */
+    if (!nc || nc->queue_index > 1) {
+        return;
+    }
+
+     /* Not support vhost-net */
+    if (get_vhost_net(nc)) {
+        return;
+    }
+
+    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", "disable",
+                        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)
 {
     QEMUSizedBuffer *buffer = NULL;
diff --git a/net/filter-buffer.c b/net/filter-buffer.c
index f0a9151..34dc312 100644
--- a/net/filter-buffer.c
+++ b/net/filter-buffer.c
@@ -16,8 +16,6 @@
 #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 1996cd9..8e74acb 100644
--- a/stubs/migration-colo.c
+++ b/stubs/migration-colo.c
@@ -48,3 +48,7 @@ bool colo_shutdown(void)
 {
     return false;
 }
+
+void colo_add_buffer_filter(const char *netdev_id, void *opaque)
+{
+}
-- 
1.8.3.1