[Qemu-devel] [PATCH 4/4] Implement virtio_net link status

[Mark McLoughlin <markmc@redhat.com>]

Implement the VIRTIO_NET_F_STATUS feature by exposing the link status
through virtio_net_config::status.

Signed-off-by: Mark McLoughlin <markmc@redhat.com>
---
 hw/virtio-net.c |   23 +++++++++++++++++++++--
 hw/virtio-net.h |    7 ++++++-
 2 files changed, 27 insertions(+), 3 deletions(-)

diff --git a/hw/virtio-net.c b/hw/virtio-net.c
index 43fde20..54c0030 100644
--- a/hw/virtio-net.c
+++ b/hw/virtio-net.c
@@ -20,6 +20,7 @@ typedef struct VirtIONet
 {
     VirtIODevice vdev;
     uint8_t mac[6];
+    uint16_t status;
     VirtQueue *rx_vq;
     VirtQueue *tx_vq;
     VLANClientState *vc;
@@ -42,13 +43,28 @@ static void virtio_net_update_config(VirtIODevice *vdev, uint8_t *config)
     VirtIONet *n = to_virtio_net(vdev);
     struct virtio_net_config netcfg;
 
+    netcfg.status = n->status;
     memcpy(netcfg.mac, n->mac, 6);
     memcpy(config, &netcfg, sizeof(netcfg));
 }
 
+static void virtio_net_set_link_status(VLANClientState *vc)
+{
+    VirtIONet *n = vc->opaque;
+    uint16_t old_status = n->status;
+
+    if (vc->link_down)
+        n->status &= ~VIRTIO_NET_S_LINK_UP;
+    else
+        n->status |= VIRTIO_NET_S_LINK_UP;
+
+    if (n->status != old_status)
+        virtio_notify_config(&n->vdev);
+}
+
 static uint32_t virtio_net_get_features(VirtIODevice *vdev)
 {
-    uint32_t features = (1 << VIRTIO_NET_F_MAC);
+    uint32_t features = (1 << VIRTIO_NET_F_MAC) | (1 << VIRTIO_NET_F_STATUS);
 
     return features;
 }
@@ -307,7 +323,8 @@ void virtio_net_init(PCIBus *bus, NICInfo *nd, int devfn)
     n = (VirtIONet *)virtio_init_pci(bus, "virtio-net", 6900, 0x1000,
                                      0, VIRTIO_ID_NET,
                                      0x02, 0x00, 0x00,
-                                     6, sizeof(VirtIONet));
+                                     sizeof(struct virtio_net_config),
+                                     sizeof(VirtIONet));
     if (!n)
         return;
 
@@ -317,8 +334,10 @@ void virtio_net_init(PCIBus *bus, NICInfo *nd, int devfn)
     n->rx_vq = virtio_add_queue(&n->vdev, 256, virtio_net_handle_rx);
     n->tx_vq = virtio_add_queue(&n->vdev, 256, virtio_net_handle_tx);
     memcpy(n->mac, nd->macaddr, 6);
+    n->status = VIRTIO_NET_S_LINK_UP;
     n->vc = qemu_new_vlan_client(nd->vlan, nd->model, nd->name,
                                  virtio_net_receive, virtio_net_can_receive, n);
+    n->vc->link_status_changed = virtio_net_set_link_status;
 
     qemu_format_nic_info_str(n->vc, n->mac);
 
diff --git a/hw/virtio-net.h b/hw/virtio-net.h
index 7446b11..148ec47 100644
--- a/hw/virtio-net.h
+++ b/hw/virtio-net.h
@@ -37,16 +37,21 @@
 #define VIRTIO_NET_F_HOST_ECN   13      /* Host can handle TSO[6] w/ ECN in. */
 #define VIRTIO_NET_F_HOST_UFO   14      /* Host can handle UFO in. */
 #define VIRTIO_NET_F_MRG_RXBUF  15      /* Host can merge receive buffers. */
+#define VIRTIO_NET_F_STATUS     16      /* virtio_net_config.status available */
+
+#define VIRTIO_NET_S_LINK_UP    1       /* Link is up */
 
 #define TX_TIMER_INTERVAL 150000 /* 150 us */
 
 /* Maximum packet size we can receive from tap device: header + 64k */
 #define VIRTIO_NET_MAX_BUFSIZE (sizeof(struct virtio_net_hdr) + (64 << 10))
 
-/* The config defining mac address (6 bytes) */
 struct virtio_net_config
 {
+    /* The config defining mac address (6 bytes) */
     uint8_t mac[6];
+    /* See VIRTIO_NET_F_STATUS and VIRTIO_NET_S_* above */
+    uint16_t status;
 } __attribute__((packed));
 
 /* This is the first element of the scatter-gather list.  If you don't
-- 
1.6.0.6