[PATCH 2/5] virtio-net: Add a virtqueue for control commands from the guest

[Alex Williamson <alex.williamson@hp.com>]

This will be used for RX mode, MAC table, VLAN table control, etc...

Signed-off-by: Alex Williamson <alex.williamson@hp.com>
---

 qemu/hw/virtio-net.c |   32 ++++++++++++++++++++++++++++++++
 qemu/hw/virtio-net.h |    3 +++
 2 files changed, 35 insertions(+), 0 deletions(-)

diff --git a/qemu/hw/virtio-net.c b/qemu/hw/virtio-net.c
index e9b3d46..99f91f2 100644
--- a/qemu/hw/virtio-net.c
+++ b/qemu/hw/virtio-net.c
@@ -27,6 +27,7 @@ typedef struct VirtIONet
     uint8_t mac[6];
     VirtQueue *rx_vq;
     VirtQueue *tx_vq;
+    VirtQueue *ctrl_vq;
     VLANClientState *vc;
     QEMUTimer *tx_timer;
     int tx_timer_active;
@@ -110,6 +111,36 @@ static void virtio_net_set_features(VirtIODevice *vdev, uint32_t features)
 #endif
 }
 
+static void virtio_net_handle_ctrl(VirtIODevice *vdev, VirtQueue *vq)
+{
+    struct {
+        uint8_t class;
+        uint8_t cmd;
+    } *ctrl;
+    uint8_t *status;
+    VirtQueueElement elem;
+
+    while (virtqueue_pop(vq, &elem)) {
+        if ((elem.in_num < 1) | (elem.out_num < 1)) {
+            fprintf(stderr, "virtio-net ctrl missing headers\n");
+            exit(1);
+        }
+
+        if (elem.out_sg[0].iov_len < sizeof(*ctrl) ||
+            elem.out_sg[elem.in_num - 1].iov_len < sizeof(*status)) {
+            fprintf(stderr, "virtio-net ctrl header not in correct element\n");
+            exit(1);
+        }
+
+        ctrl = (void *)elem.out_sg[0].iov_base;
+        status = (void *)elem.in_sg[elem.in_num - 1].iov_base;
+        *status = VIRTIO_NET_ERR;
+
+        virtqueue_push(vq, &elem, sizeof(*status));
+        virtio_notify(vdev, vq);
+    }
+}
+
 /* RX */
 
 static void virtio_net_handle_rx(VirtIODevice *vdev, VirtQueue *vq)
@@ -424,6 +455,7 @@ PCIDevice *virtio_net_init(PCIBus *bus, NICInfo *nd, int devfn)
     n->vdev.set_features = virtio_net_set_features;
     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);
+    n->ctrl_vq = virtio_add_queue(&n->vdev, 16, virtio_net_handle_ctrl);
     memcpy(n->mac, nd->macaddr, 6);
     n->vc = qemu_new_vlan_client(nd->vlan, nd->model, nd->name,
                                  virtio_net_receive, virtio_net_can_receive, n);
diff --git a/qemu/hw/virtio-net.h b/qemu/hw/virtio-net.h
index 0d9f71b..1f13123 100644
--- a/qemu/hw/virtio-net.h
+++ b/qemu/hw/virtio-net.h
@@ -77,4 +77,7 @@ struct virtio_net_hdr_mrg_rxbuf
 
 PCIDevice *virtio_net_init(PCIBus *bus, NICInfo *nd, int devfn);
 
+#define VIRTIO_NET_OK     0
+#define VIRTIO_NET_ERR    1
+
 #endif