On Mon, Oct 30, 2023 at 7:14 AM Akihiko Odaki <akihiko.od...@daynix.com>
wrote:
> vhost requires eBPF for RSS. When eBPF is not available, virtio-net
> implicitly disables RSS even if the user explicitly requests it. Return
> an error instead of implicitly disabling RSS if RSS is requested but not
> available.
>
I think that suggesting RSS feature when in fact it is not available is not
a good idea, this rather desinforms the guest.
Existing behavior (IMHO) makes more sense.
We can extend this discussion if needed, of course.
> Signed-off-by: Akihiko Odaki <akihiko.od...@daynix.com>
> ---
> hw/net/virtio-net.c | 97 ++++++++++++++++++++++-----------------------
> 1 file changed, 48 insertions(+), 49 deletions(-)
>
> diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
> index 5d4afd12b2..7bb91617d0 100644
> --- a/hw/net/virtio-net.c
> +++ b/hw/net/virtio-net.c
> @@ -792,9 +792,6 @@ static uint64_t virtio_net_get_features(VirtIODevice
> *vdev, uint64_t features,
> return features;
> }
>
> - if (!ebpf_rss_is_loaded(&n->ebpf_rss)) {
> - virtio_clear_feature(&features, VIRTIO_NET_F_RSS);
> - }
> features = vhost_net_get_features(get_vhost_net(nc->peer), features);
> vdev->backend_features = features;
>
> @@ -3533,6 +3530,50 @@ static bool
> failover_hide_primary_device(DeviceListener *listener,
> return qatomic_read(&n->failover_primary_hidden);
> }
>
> +static void virtio_net_device_unrealize(DeviceState *dev)
> +{
> + VirtIODevice *vdev = VIRTIO_DEVICE(dev);
> + VirtIONet *n = VIRTIO_NET(dev);
> + int i, max_queue_pairs;
> +
> + if (virtio_has_feature(n->host_features, VIRTIO_NET_F_RSS)) {
> + virtio_net_unload_ebpf(n);
> + }
> +
> + /* This will stop vhost backend if appropriate. */
> + virtio_net_set_status(vdev, 0);
> +
> + g_free(n->netclient_name);
> + n->netclient_name = NULL;
> + g_free(n->netclient_type);
> + n->netclient_type = NULL;
> +
> + g_free(n->mac_table.macs);
> + g_free(n->vlans);
> +
> + if (n->failover) {
> + qobject_unref(n->primary_opts);
> + device_listener_unregister(&n->primary_listener);
> + migration_remove_notifier(&n->migration_state);
> + } else {
> + assert(n->primary_opts == NULL);
> + }
> +
> + max_queue_pairs = n->multiqueue ? n->max_queue_pairs : 1;
> + for (i = 0; i < max_queue_pairs; i++) {
> + virtio_net_del_queue(n, i);
> + }
> + /* delete also control vq */
> + virtio_del_queue(vdev, max_queue_pairs * 2);
> + qemu_announce_timer_del(&n->announce_timer, false);
> + g_free(n->vqs);
> + qemu_del_nic(n->nic);
> + virtio_net_rsc_cleanup(n);
> + g_free(n->rss_data.indirections_table);
> + net_rx_pkt_uninit(n->rx_pkt);
> + virtio_cleanup(vdev);
> +}
> +
> static void virtio_net_device_realize(DeviceState *dev, Error **errp)
> {
> VirtIODevice *vdev = VIRTIO_DEVICE(dev);
> @@ -3704,53 +3745,11 @@ static void virtio_net_device_realize(DeviceState
> *dev, Error **errp)
>
> net_rx_pkt_init(&n->rx_pkt);
>
> - if (virtio_has_feature(n->host_features, VIRTIO_NET_F_RSS)) {
> - virtio_net_load_ebpf(n);
> - }
> -}
> -
> -static void virtio_net_device_unrealize(DeviceState *dev)
> -{
> - VirtIODevice *vdev = VIRTIO_DEVICE(dev);
> - VirtIONet *n = VIRTIO_NET(dev);
> - int i, max_queue_pairs;
> -
> - if (virtio_has_feature(n->host_features, VIRTIO_NET_F_RSS)) {
> - virtio_net_unload_ebpf(n);
> + if (virtio_has_feature(n->host_features, VIRTIO_NET_F_RSS) &&
> + !virtio_net_load_ebpf(n)) {
> + error_setg(errp, "Can't load eBPF RSS");
> + virtio_net_device_unrealize(dev);
> }
> -
> - /* This will stop vhost backend if appropriate. */
> - virtio_net_set_status(vdev, 0);
> -
> - g_free(n->netclient_name);
> - n->netclient_name = NULL;
> - g_free(n->netclient_type);
> - n->netclient_type = NULL;
> -
> - g_free(n->mac_table.macs);
> - g_free(n->vlans);
> -
> - if (n->failover) {
> - qobject_unref(n->primary_opts);
> - device_listener_unregister(&n->primary_listener);
> - migration_remove_notifier(&n->migration_state);
> - } else {
> - assert(n->primary_opts == NULL);
> - }
> -
> - max_queue_pairs = n->multiqueue ? n->max_queue_pairs : 1;
> - for (i = 0; i < max_queue_pairs; i++) {
> - virtio_net_del_queue(n, i);
> - }
> - /* delete also control vq */
> - virtio_del_queue(vdev, max_queue_pairs * 2);
> - qemu_announce_timer_del(&n->announce_timer, false);
> - g_free(n->vqs);
> - qemu_del_nic(n->nic);
> - virtio_net_rsc_cleanup(n);
> - g_free(n->rss_data.indirections_table);
> - net_rx_pkt_uninit(n->rx_pkt);
> - virtio_cleanup(vdev);
> }
>
> static void virtio_net_reset(VirtIODevice *vdev)
> --
> 2.42.0
>
>
