[PATCH] replay: improve determinism of virtio-net

[Pavel Dovgalyuk]

virtio-net device uses bottom halves for callbacks.
These callbacks should be deterministic, because they affect VM state.
This patch replaces BH invocations with corresponding replay functions,
making them deterministic in record/replay mode.
This patch also disables guest announce timers for record/replay,
because they break correct loadvm in deterministic mode.

Signed-off-by: Pavel Dovgalyuk <Pavel.Dovgalyuk@ispras.ru>
---
 hw/net/virtio-net.c |   13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
index 6b7e8dd04e..e876363236 100644
--- a/hw/net/virtio-net.c
+++ b/hw/net/virtio-net.c
@@ -44,6 +44,7 @@
 #include "hw/pci/pci.h"
 #include "net_rx_pkt.h"
 #include "hw/virtio/vhost.h"
+#include "sysemu/replay.h"
 
 #define VIRTIO_NET_VM_VERSION    11
 
@@ -394,7 +395,7 @@ static void virtio_net_set_status(struct VirtIODevice 
*vdev, uint8_t status)
                 timer_mod(q->tx_timer,
                                qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) + 
n->tx_timeout);
             } else {
-                qemu_bh_schedule(q->tx_bh);
+                replay_bh_schedule_event(q->tx_bh);
             }
         } else {
             if (q->tx_timer) {
@@ -2546,7 +2547,7 @@ static void virtio_net_handle_tx_bh(VirtIODevice *vdev, 
VirtQueue *vq)
         return;
     }
     virtio_queue_set_notification(vq, 0);
-    qemu_bh_schedule(q->tx_bh);
+    replay_bh_schedule_event(q->tx_bh);
 }
 
 static void virtio_net_tx_timer(void *opaque)
@@ -2602,7 +2603,7 @@ static void virtio_net_tx_bh(void *opaque)
     /* If we flush a full burst of packets, assume there are
      * more coming and immediately reschedule */
     if (ret >= n->tx_burst) {
-        qemu_bh_schedule(q->tx_bh);
+        replay_bh_schedule_event(q->tx_bh);
         q->tx_waiting = 1;
         return;
     }
@@ -2616,7 +2617,7 @@ static void virtio_net_tx_bh(void *opaque)
         return;
     } else if (ret > 0) {
         virtio_queue_set_notification(q->tx_vq, 0);
-        qemu_bh_schedule(q->tx_bh);
+        replay_bh_schedule_event(q->tx_bh);
         q->tx_waiting = 1;
     }
 }
@@ -3206,6 +3207,10 @@ static void virtio_net_device_realize(DeviceState *dev, 
Error **errp)
         n->host_features |= (1ULL << VIRTIO_NET_F_MTU);
     }
 
+    if (replay_mode != REPLAY_MODE_NONE) {
+        n->host_features &= ~(1ULL << VIRTIO_NET_F_GUEST_ANNOUNCE);
+    }
+
     if (n->net_conf.duplex_str) {
         if (strncmp(n->net_conf.duplex_str, "half", 5) == 0) {
             n->net_conf.duplex = DUPLEX_HALF;