[PATCH v2 4/5] 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>
---
 include/net/vhost-vdpa.h |  1 +
 hw/net/vhost_net.c       |  8 +++++
 net/vhost-vdpa.c         | 64 ++++++++++++++++++++++++++++++++++++++--
 3 files changed, 71 insertions(+), 2 deletions(-)

diff --git a/include/net/vhost-vdpa.h b/include/net/vhost-vdpa.h
index b81f9a6f2a..38d65e845d 100644
--- a/include/net/vhost-vdpa.h
+++ b/include/net/vhost-vdpa.h
@@ -15,6 +15,7 @@
 #define TYPE_VHOST_VDPA "vhost-vdpa"
 
 struct vhost_net *vhost_vdpa_get_vhost_net(NetClientState *nc);
+int vhost_vdpa_start(NetClientState *nc);
 
 extern const int vdpa_feature_bits[];
 
diff --git a/hw/net/vhost_net.c b/hw/net/vhost_net.c
index ccac5b7a64..f9cebd9716 100644
--- a/hw/net/vhost_net.c
+++ b/hw/net/vhost_net.c
@@ -274,6 +274,13 @@ static int vhost_net_start_one(struct vhost_net *net,
             }
         }
     }
+
+    if (net->nc->info->type == NET_CLIENT_DRIVER_VHOST_VDPA) {
+        r = vhost_vdpa_start(net->nc);
+        if (r < 0) {
+            goto fail;
+        }
+    }
     return 0;
 fail:
     file.fd = -1;
@@ -373,6 +380,7 @@ int vhost_net_start(VirtIODevice *dev, NetClientState *ncs,
         r = vhost_net_start_one(get_vhost_net(peer), dev);
 
         if (r < 0) {
+            vhost_net_stop_one(get_vhost_net(peer), dev);
             goto err_start;
         }
 
diff --git a/net/vhost-vdpa.c b/net/vhost-vdpa.c
index 533bd9f680..84e90f067a 100644
--- a/net/vhost-vdpa.c
+++ b/net/vhost-vdpa.c
@@ -342,9 +342,12 @@ static virtio_net_ctrl_ack vhost_vdpa_net_cvq_add(VhostShadowVirtqueue *svq,
     virtio_net_ctrl_ack status;
     size_t dev_written;
     int r;
-    void *unused = (void *)1;
 
-    r = vhost_svq_add(svq, &dev_buffers[0], 1, &dev_buffers[1], 1, unused);
+    /*
+     * Add a fake non-NULL VirtQueueElement since we'll remove before SVQ
+     * event loop can get it.
+     */
+    r = vhost_svq_add(svq, &dev_buffers[0], 1, &dev_buffers[1], 1, (void *)1);
     if (unlikely(r != 0)) {
         if (unlikely(r == -ENOSPC)) {
             qemu_log_mask(LOG_GUEST_ERROR, "%s: No space on device queue\n",
@@ -372,6 +375,63 @@ static virtio_net_ctrl_ack vhost_vdpa_net_cvq_add(VhostShadowVirtqueue *svq,
     return VIRTIO_NET_OK;
 }
 
+int vhost_vdpa_start(NetClientState *nc)
+{
+    VhostVDPAState *s = DO_UPCAST(VhostVDPAState, nc, nc);
+    struct vhost_vdpa *v = &s->vhost_vdpa;
+    VirtIONet *n = VIRTIO_NET(v->dev->vdev);
+    uint64_t features = v->dev->vdev->host_features;
+    VhostShadowVirtqueue *svq;
+
+    if (!v->shadow_vqs_enabled) {
+        return 0;
+    }
+
+    if (v->dev->vq_index + v->dev->nvqs != v->dev->vq_index_end) {
+        /* Only interested in CVQ */
+        return 0;
+    }
+
+    assert(nc->info->type == NET_CLIENT_DRIVER_VHOST_VDPA);
+
+    svq = g_ptr_array_index(v->shadow_vqs, 0);
+    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_cvq_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