[RFC PATCH 11/12] vdpa: Add virtio-net mac address via CVQ at start

["Eugenio Pérez" <eperezma@redhat.com>]

This is needed so the destination vdpa device see the same state a the
guest set in the source.

Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
---
 net/vhost-vdpa.c | 53 +++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 52 insertions(+), 1 deletion(-)

diff --git a/net/vhost-vdpa.c b/net/vhost-vdpa.c
index 0183fce353..2873be2ba4 100644
--- a/net/vhost-vdpa.c
+++ b/net/vhost-vdpa.c
@@ -383,7 +383,7 @@ static virtio_net_ctrl_ack vhost_vdpa_net_svq_add(VhostShadowVirtqueue *svq,
     return VIRTIO_NET_OK;
 }
 
-static int vhost_vdpa_start_control_svq(struct vhost_vdpa *v)
+static int vhost_vdpa_enable_control_svq(struct vhost_vdpa *v)
 {
     struct vhost_vring_state state = {
         .index = v->dev->vq_index,
@@ -395,6 +395,57 @@ static int vhost_vdpa_start_control_svq(struct vhost_vdpa *v)
     return r < 0 ? -errno : r;
 }
 
+static int vhost_vdpa_start_control_svq(struct vhost_vdpa *v)
+{
+
+    VirtIONet *n = VIRTIO_NET(v->dev->vdev);
+    uint64_t features = v->dev->vdev->host_features;
+    VhostShadowVirtqueue *svq = g_ptr_array_index(v->shadow_vqs, 0);
+    VhostVDPAState *s = container_of(v, VhostVDPAState, vhost_vdpa);
+    int r;
+
+    r = vhost_vdpa_enable_control_svq(v);
+    if (unlikely(r < 0)) {
+        return r;
+    }
+
+    if (features & BIT_ULL(VIRTIO_NET_F_CTRL_MAC_ADDR)) {
+        const struct virtio_net_ctrl_hdr ctrl = {
+            .class = VIRTIO_NET_CTRL_MAC,
+            .cmd = VIRTIO_NET_CTRL_MAC_ADDR_SET,
+        };
+        uint8_t mac[6];
+        const struct iovec out[] = {
+            {
+                .iov_base = (void *)&ctrl,
+                .iov_len = sizeof(ctrl),
+            },{
+                .iov_base = mac,
+                .iov_len = sizeof(mac),
+            },
+        };
+        struct iovec dev_buffers[2] = {
+            { .iov_base = s->cvq_cmd_out_buffer },
+            { .iov_base = s->cvq_cmd_in_buffer },
+        };
+        bool ok;
+        virtio_net_ctrl_ack state;
+
+        ok = vhost_vdpa_net_cvq_map_sg(s, out, ARRAY_SIZE(out), dev_buffers);
+        if (unlikely(!ok)) {
+            return -1;
+        }
+
+        memcpy(mac, n->mac, sizeof(mac));
+        state = vhost_vdpa_net_svq_add(svq, dev_buffers);
+        vhost_vdpa_cvq_unmap_buf(v, dev_buffers[0].iov_base);
+        vhost_vdpa_cvq_unmap_buf(v, dev_buffers[1].iov_base);
+        return state == VIRTIO_NET_OK ? 0 : 1;
+    }
+
+    return 0;
+}
+
 /**
  * Do not forward commands not supported by SVQ. Otherwise, the device could
  * accept it and qemu would not know how to update the device model.
-- 
2.31.1