[PATCH 05/40] vdpa: populate desc_group from net_vhost_vdpa_init

[Si-Wei Liu <si-wei.liu@oracle.com>]

Add the desc_group field to struct vhost_vdpa, and get it
populated when the corresponding vq is initialized at
net_vhost_vdpa_init. If the vq does not have descriptor
group capability, or it doesn't have a dedicated ASID
group to host descriptors other than the data buffers,
desc_group will be set to a negative value -1.

Signed-off-by: Si-Wei Liu <si-wei.liu@oracle.com>
---
 include/hw/virtio/vhost-vdpa.h |  1 +
 net/vhost-vdpa.c               | 15 +++++++++++++--
 2 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/include/hw/virtio/vhost-vdpa.h b/include/hw/virtio/vhost-vdpa.h
index 6533ad2..63493ff 100644
--- a/include/hw/virtio/vhost-vdpa.h
+++ b/include/hw/virtio/vhost-vdpa.h
@@ -87,6 +87,7 @@ typedef struct vhost_vdpa {
     Error *migration_blocker;
     VhostVDPAHostNotifier notifier[VIRTIO_QUEUE_MAX];
     IOMMUNotifier n;
+    int64_t desc_group;
 } VhostVDPA;
 
 int vhost_vdpa_get_iova_range(int fd, struct vhost_vdpa_iova_range *iova_range);
diff --git a/net/vhost-vdpa.c b/net/vhost-vdpa.c
index cb5705d..1a738b2 100644
--- a/net/vhost-vdpa.c
+++ b/net/vhost-vdpa.c
@@ -1855,11 +1855,22 @@ static NetClientState *net_vhost_vdpa_init(NetClientState *peer,
 
     ret = vhost_vdpa_add(nc, (void *)&s->vhost_vdpa, queue_pair_index, nvqs);
     if (ret) {
-        qemu_del_net_client(nc);
-        return NULL;
+        goto err;
     }
 
+    if (is_datapath) {
+        ret = vhost_vdpa_probe_desc_group(vdpa_device_fd, features,
+                                          0, &desc_group, errp);
+        if (unlikely(ret < 0)) {
+            goto err;
+        }
+    }
+    s->vhost_vdpa.desc_group = desc_group;
     return nc;
+
+err:
+    qemu_del_net_client(nc);
+    return NULL;
 }
 
 static int vhost_vdpa_get_features(int fd, uint64_t *features, Error **errp)
-- 
1.8.3.1