[Qemu-devel] [PATCH v3 3/5] virtio_net: Add a query command for FAILOVER_STANDBY_CHANGED event.

[Venu Busireddy]

Add a query command to check the status of the FAILOVER_STANDBY_CHANGED
state of the virtio_net devices.

Signed-off-by: Venu Busireddy <address@hidden>
---
 hw/net/virtio-net.c            | 16 +++++++++++
 include/hw/virtio/virtio-net.h |  1 +
 include/net/net.h              |  2 ++
 net/net.c                      | 61 ++++++++++++++++++++++++++++++++++++++++++
 qapi/net.json                  | 46 +++++++++++++++++++++++++++++++
 5 files changed, 126 insertions(+)

diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
index 7b1bcde..a4e07ac 100644
--- a/hw/net/virtio-net.c
+++ b/hw/net/virtio-net.c
@@ -263,9 +263,11 @@ static void virtio_net_failover_notify_event(VirtIONet *n, 
uint8_t status)
          */
         if ((status & VIRTIO_CONFIG_S_DRIVER_OK) &&
                 (!(vdev->status & VIRTIO_CONFIG_S_DRIVER_OK))) {
+            n->standby_enabled = true;
             qapi_event_send_failover_standby_changed(!!ncn, ncn, path, true);
         } else if ((!(status & VIRTIO_CONFIG_S_DRIVER_OK)) &&
                 (vdev->status & VIRTIO_CONFIG_S_DRIVER_OK)) {
+            n->standby_enabled = false;
             qapi_event_send_failover_standby_changed(!!ncn, ncn, path, false);
         }
     }
@@ -448,6 +450,19 @@ static RxFilterInfo 
*virtio_net_query_rxfilter(NetClientState *nc)
     return info;
 }
 
+static StandbyStatusInfo *virtio_net_query_standby_status(NetClientState *nc)
+{
+    StandbyStatusInfo *info;
+    VirtIONet *n = qemu_get_nic_opaque(nc);
+
+    info = g_malloc0(sizeof(*info));
+    info->device = g_strdup(n->netclient_name);
+    info->path = g_strdup(object_get_canonical_path(OBJECT(n->qdev)));
+    info->enabled = n->standby_enabled;
+
+    return info;
+}
+
 static void virtio_net_reset(VirtIODevice *vdev)
 {
     VirtIONet *n = VIRTIO_NET(vdev);
@@ -1923,6 +1938,7 @@ static NetClientInfo net_virtio_info = {
     .receive = virtio_net_receive,
     .link_status_changed = virtio_net_set_link_status,
     .query_rx_filter = virtio_net_query_rxfilter,
+    .query_standby_status = virtio_net_query_standby_status,
 };
 
 static bool virtio_net_guest_notifier_pending(VirtIODevice *vdev, int idx)
diff --git a/include/hw/virtio/virtio-net.h b/include/hw/virtio/virtio-net.h
index 4d7f3c8..9071e96 100644
--- a/include/hw/virtio/virtio-net.h
+++ b/include/hw/virtio/virtio-net.h
@@ -103,6 +103,7 @@ typedef struct VirtIONet {
     int announce_counter;
     bool needs_vnet_hdr_swap;
     bool mtu_bypass_backend;
+    bool standby_enabled;
 } VirtIONet;
 
 void virtio_net_set_netclient_name(VirtIONet *n, const char *name,
diff --git a/include/net/net.h b/include/net/net.h
index ec13702..61e8513 100644
--- a/include/net/net.h
+++ b/include/net/net.h
@@ -50,6 +50,7 @@ typedef void (NetCleanup) (NetClientState *);
 typedef void (LinkStatusChanged)(NetClientState *);
 typedef void (NetClientDestructor)(NetClientState *);
 typedef RxFilterInfo *(QueryRxFilter)(NetClientState *);
+typedef StandbyStatusInfo *(QueryStandbyStatus)(NetClientState *);
 typedef bool (HasUfo)(NetClientState *);
 typedef bool (HasVnetHdr)(NetClientState *);
 typedef bool (HasVnetHdrLen)(NetClientState *, int);
@@ -71,6 +72,7 @@ typedef struct NetClientInfo {
     NetCleanup *cleanup;
     LinkStatusChanged *link_status_changed;
     QueryRxFilter *query_rx_filter;
+    QueryStandbyStatus *query_standby_status;
     NetPoll *poll;
     HasUfo *has_ufo;
     HasVnetHdr *has_vnet_hdr;
diff --git a/net/net.c b/net/net.c
index 1f7d626..fbf288e 100644
--- a/net/net.c
+++ b/net/net.c
@@ -1320,6 +1320,67 @@ RxFilterInfoList *qmp_query_rx_filter(bool has_name, 
const char *name,
     return filter_list;
 }
 
+StandbyStatusInfoList *qmp_query_standby_status(bool has_device,
+                                                const char *device,
+                                                Error **errp)
+{
+    NetClientState *nc;
+    StandbyStatusInfoList *status_list = NULL, *last_entry = NULL;
+
+    QTAILQ_FOREACH(nc, &net_clients, next) {
+        StandbyStatusInfoList *entry;
+        StandbyStatusInfo *info;
+
+        if (has_device && strcmp(nc->name, device) != 0) {
+            continue;
+        }
+
+        /* only query standby status information of NIC */
+        if (nc->info->type != NET_CLIENT_DRIVER_NIC) {
+            if (has_device) {
+                error_setg(errp, "net client(%s) isn't a NIC", device);
+                return NULL;
+            }
+            continue;
+        }
+
+        /*
+         * only query information on queue 0 since the info is per nic,
+         * not per queue.
+         */
+        if (nc->queue_index != 0) {
+            continue;
+        }
+
+        if (nc->info->query_standby_status) {
+            info = nc->info->query_standby_status(nc);
+            entry = g_malloc0(sizeof(*entry));
+            entry->value = info;
+
+            if (!status_list) {
+                status_list = entry;
+            } else {
+                last_entry->next = entry;
+            }
+            last_entry = entry;
+        } else if (has_device) {
+            error_setg(errp, "net client(%s) doesn't support"
+                       " standby status querying", device);
+            return NULL;
+        }
+
+        if (has_device) {
+            break;
+        }
+    }
+
+    if (status_list == NULL && has_device) {
+        error_setg(errp, "invalid net client name: %s", device);
+    }
+
+    return status_list;
+}
+
 void hmp_info_network(Monitor *mon, const QDict *qdict)
 {
     NetClientState *nc, *peer;
diff --git a/qapi/net.json b/qapi/net.json
index 6a6d6fe..633ac87 100644
--- a/qapi/net.json
+++ b/qapi/net.json
@@ -711,3 +711,49 @@
 ##
 { 'event': 'FAILOVER_STANDBY_CHANGED',
   'data': {'*device': 'str', 'path': 'str', 'enabled': 'bool'} }
+
+##
+# @StandbyStatusInfo:
+#
+# Standby status information for a virtio_net device.
+#
+# @device: Indicates the virtio_net device.
+#
+# @path: Indicates the device path.
+#
+# @enabled: true if the virtio_net driver is loaded.
+#           false if the virtio_net driver is unloaded or the guest rebooted.
+#
+# Since: 4.0
+##
+{ 'struct': 'StandbyStatusInfo',
+  'data': {'device': 'str', 'path': 'str', 'enabled': 'bool'} }
+
+##
+# @query-standby-status:
+#
+# Return Standby status information for all virtio_net devices,
+#        or for the given virtio_net device.
+#
+# @device: Name of the virtio_net device.
+#
+# Returns: List of @StandbyStatusInfo for all virtio_net devices,
+#          or for the given virtio_net device.
+#          Returns an error if the given @device doesn't exist.
+#
+# Since: 4.0
+#
+# Example:
+#
+# -> { "execute": "query-standby-status", "arguments": { "device": "net0" } }
+# <- { "return": [
+#                  { 'device': 'net0',
+#                    'path': '/machine/peripheral/net0/virtio-backend',
+#                    'enabled': 'true'
+#                  }
+#                ]
+#    }
+#
+##
+{ 'command': 'query-standby-status', 'data': { '*device': 'str' },
+  'returns': ['StandbyStatusInfo'] }