[Qemu-devel] [PATCH] vhost-net: Do not set features for backend when peer was deleted

[Jason Wang <jasowang@redhat.com>]

When hot-unplug a virtio nic with vhost-net backend, guest may
continue to program the nic even if its peer have been deleted. We can
not set features at this time as vhost_net_ack_features() may still
try to use the tap related vhost_net structure which have been freed
in tap_cleanup(). And setting offload features for a deleted backend
is also meaningless in this situation

Signed-off-by: Jason Wang <jasowang@redhat.com>
---
 hw/virtio-net.c |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)

diff --git a/hw/virtio-net.c b/hw/virtio-net.c
index 7e1688c..68c8e48 100644
--- a/hw/virtio-net.c
+++ b/hw/virtio-net.c
@@ -245,6 +245,9 @@ static void virtio_net_set_features(VirtIODevice *vdev, uint32_t features)
 {
     VirtIONet *n = to_virtio_net(vdev);
 
+    if (n->nic->peer_deleted)
+        return;
+
     n->mergeable_rx_bufs = !!(features & (1 << VIRTIO_NET_F_MRG_RXBUF));
 
     if (n->has_vnet_hdr) {