Net patches

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Merge remote-tracking branch 'remotes/stefanha/tags/net-pull-request' into staging

Net patches

# gpg: Signature made Thu 04 Sep 2014 17:32:44 BST using RSA key ID 81AB73C8
# gpg: Good signature from "Stefan Hajnoczi <stefanha@redhat.com>"
# gpg:                 aka "Stefan Hajnoczi <stefanha@gmail.com>"

* remotes/stefanha/tags/net-pull-request:
  virtio-net: purge outstanding packets when starting vhost
  net: complete all queued packets on VM stop
  net: invoke callback when purging queue
  virtio: don't call device on !vm_running
  virtio-net: don't run bh on vm stopped
  net: Forbid dealing with packets when VM is not running

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

hw/net/virtio-net.c

@@ -125,10 +125,23 @@ static void virtio_net_vhost_status(VirtIONet *n, uint8_t status)
         return;
     }
     if (!n->vhost_started) {
-        int r;
+        int r, i;
+
         if (!vhost_net_query(get_vhost_net(nc->peer), vdev)) {
             return;
         }
+
+        /* Any packets outstanding? Purge them to avoid touching rings
+         * when vhost is running.
+         */
+        for (i = 0;  i < queues; i++) {
+            NetClientState *qnc = qemu_get_subqueue(n->nic, i);
+
+            /* Purge both directions: TX and RX. */
+            qemu_net_queue_purge(qnc->peer->incoming_queue, qnc);
+            qemu_net_queue_purge(qnc->incoming_queue, qnc->peer);
+        }
+
         n->vhost_started = 1;
         r = vhost_net_start(vdev, n->nic->ncs, queues);
         if (r < 0) {

hw/virtio/virtio.c

@@ -1108,7 +1108,10 @@ static void virtio_vmstate_change(void *opaque, int running, RunState state)
     BusState *qbus = qdev_get_parent_bus(DEVICE(vdev));
     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
     bool backend_run = running && (vdev->status & VIRTIO_CONFIG_S_DRIVER_OK);
-    vdev->vm_running = running;
+
+    if (running) {
+        vdev->vm_running = running;
+    }
 
     if (backend_run) {
         virtio_set_status(vdev, vdev->status);
@@ -1121,6 +1124,10 @@ static void virtio_vmstate_change(void *opaque, int running, RunState state)
     if (!backend_run) {
         virtio_set_status(vdev, vdev->status);
     }
+
+    if (!running) {
+        vdev->vm_running = running;
+    }
 }
 
 void virtio_init(VirtIODevice *vdev, const char *name,

net/net.c

@@ -41,12 +41,14 @@
 #include "qapi-visit.h"
 #include "qapi/opts-visitor.h"
 #include "qapi/dealloc-visitor.h"
+#include "sysemu/sysemu.h"
 
 /* Net bridge is currently not supported for W32. */
 #if !defined(_WIN32)
 # define CONFIG_NET_BRIDGE
 #endif
 
+static VMChangeStateEntry *net_change_state_entry;
 static QTAILQ_HEAD(, NetClientState) net_clients;
 
 const char *host_net_devices[] = {
@@ -452,6 +454,12 @@ void qemu_set_vnet_hdr_len(NetClientState *nc, int len)
 
 int qemu_can_send_packet(NetClientState *sender)
 {
+    int vm_running = runstate_is_running();
+
+    if (!vm_running) {
+        return 0;
+    }
+
     if (!sender->peer) {
         return 1;
     }
@@ -504,7 +512,8 @@ void qemu_purge_queued_packets(NetClientState *nc)
     qemu_net_queue_purge(nc->peer->incoming_queue, nc);
 }
 
-void qemu_flush_queued_packets(NetClientState *nc)
+static
+void qemu_flush_or_purge_queued_packets(NetClientState *nc, bool purge)
 {
     nc->receive_disabled = 0;
 
@@ -518,9 +527,17 @@ void qemu_flush_queued_packets(NetClientState *nc)
          * the file descriptor (for tap, for example).
          */
         qemu_notify_event();
+    } else if (purge) {
+        /* Unable to empty the queue, purge remaining packets */
+        qemu_net_queue_purge(nc->incoming_queue, nc);
     }
 }
 
+void qemu_flush_queued_packets(NetClientState *nc)
+{
+    qemu_flush_or_purge_queued_packets(nc, false);
+}
+
 static ssize_t qemu_send_packet_async_with_flags(NetClientState *sender,
                                                  unsigned flags,
                                                  const uint8_t *buf, int size,
@@ -1168,6 +1185,22 @@ void qmp_set_link(const char *name, bool up, Error **errp)
     }
 }
 
+static void net_vm_change_state_handler(void *opaque, int running,
+                                        RunState state)
+{
+    /* Complete all queued packets, to guarantee we don't modify
+     * state later when VM is not running.
+     */
+    if (!running) {
+        NetClientState *nc;
+        NetClientState *tmp;
+
+        QTAILQ_FOREACH_SAFE(nc, &net_clients, next, tmp) {
+            qemu_flush_or_purge_queued_packets(nc, true);
+        }
+    }
+}
+
 void net_cleanup(void)
 {
     NetClientState *nc;
@@ -1183,6 +1216,8 @@ void net_cleanup(void)
             qemu_del_net_client(nc);
         }
     }
+
+    qemu_del_vm_change_state_handler(net_change_state_entry);
 }
 
 void net_check_clients(void)
@@ -1268,6 +1303,9 @@ int net_init_clients(void)
 #endif
     }
 
+    net_change_state_entry =
+        qemu_add_vm_change_state_handler(net_vm_change_state_handler, NULL);
+
     QTAILQ_INIT(&net_clients);
 
     if (qemu_opts_foreach(qemu_find_opts("netdev"), net_init_netdev, NULL, 1) == -1)

net/queue.c

@@ -233,6 +233,9 @@ void qemu_net_queue_purge(NetQueue *queue, NetClientState *from)
         if (packet->sender == from) {
             QTAILQ_REMOVE(&queue->packets, packet, entry);
             queue->nq_count--;
+            if (packet->sent_cb) {
+                packet->sent_cb(packet->sender, 0);
+            }
             g_free(packet);
         }
     }