[PATCH v9 05/12] vhost_net: Add NetClientInfo start callback

[Eugenio Pérez]

This is used by the backend to perform actions before the device is
started.

In particular, vdpa net use it to map CVQ buffers to the device, so it
can send control commands using them.

Signed-off-by: Eugenio Pérez <epere...@redhat.com>
Acked-by: Jason Wang <jasow...@redhat.com>
---
v9: Rename also in patch message
v8: Rename NetClientInfo prepare callback to start, so it aligns with
    future "stop"
---
 include/net/net.h  | 2 ++
 hw/net/vhost_net.c | 7 +++++++
 2 files changed, 9 insertions(+)

diff --git a/include/net/net.h b/include/net/net.h
index 523136c7ac..ad9e80083a 100644
--- a/include/net/net.h
+++ b/include/net/net.h
@@ -44,6 +44,7 @@ typedef struct NICConf {
 
 typedef void (NetPoll)(NetClientState *, bool enable);
 typedef bool (NetCanReceive)(NetClientState *);
+typedef int (NetStart)(NetClientState *);
 typedef ssize_t (NetReceive)(NetClientState *, const uint8_t *, size_t);
 typedef ssize_t (NetReceiveIOV)(NetClientState *, const struct iovec *, int);
 typedef void (NetCleanup) (NetClientState *);
@@ -71,6 +72,7 @@ typedef struct NetClientInfo {
     NetReceive *receive_raw;
     NetReceiveIOV *receive_iov;
     NetCanReceive *can_receive;
+    NetStart *start;
     NetCleanup *cleanup;
     LinkStatusChanged *link_status_changed;
     QueryRxFilter *query_rx_filter;
diff --git a/hw/net/vhost_net.c b/hw/net/vhost_net.c
index ccac5b7a64..2e0baeba26 100644
--- a/hw/net/vhost_net.c
+++ b/hw/net/vhost_net.c
@@ -244,6 +244,13 @@ static int vhost_net_start_one(struct vhost_net *net,
     struct vhost_vring_file file = { };
     int r;
 
+    if (net->nc->info->start) {
+        r = net->nc->info->start(net->nc);
+        if (r < 0) {
+            return r;
+        }
+    }
+
     r = vhost_dev_enable_notifiers(&net->dev, dev);
     if (r < 0) {
         goto fail_notifiers;
-- 
2.31.1