[PATCH 2/2] qemu: add linkspeed and duplex setting to virtio-net

[Jason Baron]

Although they can be currently set in linux via 'ethtool -s', this requires
guest changes, and thus it would be nice to extend this functionality such
that it can be configured automatically from the host (as other network
do).

Linkspeed and duplex settings can be set as:
'-device virtio-net,speed=10000,duplex=full'

where speed is [-1...INT_MAX], and duplex is ["half"|"full"].

Signed-off-by: Jason Baron <jbaron@xxxxxxxxxx>
Cc: "Michael S. Tsirkin" <mst@xxxxxxxxxx>
Cc: Jason Wang <jasowang@xxxxxxxxxx>
---
 hw/net/virtio-net.c                         | 29 +++++++++++++++++++++++++++++
 include/hw/virtio/virtio-net.h              |  3 +++
 include/standard-headers/linux/virtio_net.h |  4 ++++
 3 files changed, 36 insertions(+)

diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
index 38674b0..d63e790 100644
--- a/hw/net/virtio-net.c
+++ b/hw/net/virtio-net.c
@@ -40,6 +40,12 @@
 #define VIRTIO_NET_RX_QUEUE_MIN_SIZE VIRTIO_NET_RX_QUEUE_DEFAULT_SIZE
 #define VIRTIO_NET_TX_QUEUE_MIN_SIZE VIRTIO_NET_TX_QUEUE_DEFAULT_SIZE
 
+/* duplex and speed defines */
+#define DUPLEX_UNKNOWN          0xff
+#define DUPLEX_HALF             0x00
+#define DUPLEX_FULL             0x01
+#define SPEED_UNKNOWN           -1
+
 /*
  * Calculate the number of bytes up to and including the given 'field' of
  * 'container'.
@@ -61,6 +67,8 @@ static VirtIOFeature feature_sizes[] = {
      .end = endof(struct virtio_net_config, max_virtqueue_pairs)},
     {.flags = 1 << VIRTIO_NET_F_MTU,
      .end = endof(struct virtio_net_config, mtu)},
+    {.flags = 1 << VIRTIO_NET_F_SPEED_DUPLEX,
+     .end = endof(struct virtio_net_config, duplex)},
     {}
 };
 
@@ -88,6 +96,8 @@ static void virtio_net_get_config(VirtIODevice *vdev, uint8_t *config)
     virtio_stw_p(vdev, &netcfg.status, n->status);
     virtio_stw_p(vdev, &netcfg.max_virtqueue_pairs, n->max_queues);
     virtio_stw_p(vdev, &netcfg.mtu, n->net_conf.mtu);
+    virtio_stl_p(vdev, &netcfg.speed, n->net_conf.speed);
+    netcfg.duplex = n->net_conf.duplex;
     memcpy(netcfg.mac, n->mac, ETH_ALEN);
     memcpy(config, &netcfg, n->config_size);
 }
@@ -1941,6 +1951,23 @@ static void virtio_net_device_realize(DeviceState *dev, Error **errp)
         n->host_features |= (0x1 << VIRTIO_NET_F_MTU);
     }
 
+    n->host_features |= (0x1 << VIRTIO_NET_F_SPEED_DUPLEX);
+    if (n->net_conf.duplex_str) {
+        if (strncmp(n->net_conf.duplex_str, "half", 5) == 0) {
+            n->net_conf.duplex = DUPLEX_HALF;
+        } else if (strncmp(n->net_conf.duplex_str, "full", 5) == 0) {
+            n->net_conf.duplex = DUPLEX_FULL;
+        } else {
+            error_setg(errp, "'duplex' must be 'half' or 'full'");
+        }
+    } else {
+        n->net_conf.duplex = DUPLEX_UNKNOWN;
+    }
+    if (n->net_conf.speed < SPEED_UNKNOWN) {
+            error_setg(errp, "'speed' must be between -1 (SPEED_UNKOWN) and "
+                       "INT_MAX");
+    }
+
     virtio_net_set_config_size(n, n->host_features);
     virtio_init(vdev, "virtio-net", VIRTIO_ID_NET, n->config_size);
 
@@ -2160,6 +2187,8 @@ static Property virtio_net_properties[] = {
     DEFINE_PROP_UINT16("host_mtu", VirtIONet, net_conf.mtu, 0),
     DEFINE_PROP_BOOL("x-mtu-bypass-backend", VirtIONet, mtu_bypass_backend,
                      true),
+    DEFINE_PROP_INT32("speed", VirtIONet, net_conf.speed, SPEED_UNKNOWN),
+    DEFINE_PROP_STRING("duplex", VirtIONet, net_conf.duplex_str),
     DEFINE_PROP_END_OF_LIST(),
 };
 
diff --git a/include/hw/virtio/virtio-net.h b/include/hw/virtio/virtio-net.h
index b81b6a4..af74a94 100644
--- a/include/hw/virtio/virtio-net.h
+++ b/include/hw/virtio/virtio-net.h
@@ -38,6 +38,9 @@ typedef struct virtio_net_conf
     uint16_t rx_queue_size;
     uint16_t tx_queue_size;
     uint16_t mtu;
+    int32_t speed;
+    char *duplex_str;
+    uint8_t duplex;
 } virtio_net_conf;
 
 /* Maximum packet size we can receive from tap device: header + 64k */
diff --git a/include/standard-headers/linux/virtio_net.h b/include/standard-headers/linux/virtio_net.h
index 30ff249..0ff1447 100644
--- a/include/standard-headers/linux/virtio_net.h
+++ b/include/standard-headers/linux/virtio_net.h
@@ -36,6 +36,7 @@
 #define VIRTIO_NET_F_GUEST_CSUM	1	/* Guest handles pkts w/ partial csum */
 #define VIRTIO_NET_F_CTRL_GUEST_OFFLOADS 2 /* Dynamic offload configuration. */
 #define VIRTIO_NET_F_MTU	3	/* Initial MTU advice */
+#define VIRTIO_NET_F_SPEED_DUPLEX 4	/* Host set linkspeed and duplex */
 #define VIRTIO_NET_F_MAC	5	/* Host has given MAC address. */
 #define VIRTIO_NET_F_GUEST_TSO4	7	/* Guest can handle TSOv4 in. */
 #define VIRTIO_NET_F_GUEST_TSO6	8	/* Guest can handle TSOv6 in. */
@@ -76,6 +77,9 @@ struct virtio_net_config {
 	uint16_t max_virtqueue_pairs;
 	/* Default maximum transmit unit advice */
 	uint16_t mtu;
+	/* Host exported linkspeed and duplex */
+	uint32_t speed;
+	uint8_t duplex;
 } QEMU_PACKED;
 
 /*
-- 
2.6.1