Re: [RFC PATCH 2/3] vdpa: Restore receive-side scaling state

[Hawkins Jiawei <yin31149@gmail.com>]

On 2023/8/11 23:28, Hawkins Jiawei wrote:
> This patch reuses vhost_vdpa_net_load_rss() with some
> refactorings to restore the receive-side scaling state
> at device's startup.
>
> Signed-off-by: Hawkins Jiawei <yin31149@gmail.com>
> ---
>   net/vhost-vdpa.c | 53 ++++++++++++++++++++++++++++++++----------------
>   1 file changed, 35 insertions(+), 18 deletions(-)
>
> diff --git a/net/vhost-vdpa.c b/net/vhost-vdpa.c
> index 4c8e4b19f6..7870cbe142 100644
> --- a/net/vhost-vdpa.c
> +++ b/net/vhost-vdpa.c
> @@ -820,17 +820,28 @@ static int vhost_vdpa_net_load_rss(VhostVDPAState *s, const VirtIONet *n,
>       }
>
>       cfg.hash_types = cpu_to_le32(n->rss_data.hash_types);
> -    /*
> -     * According to VirtIO standard, "Field reserved MUST contain zeroes.
> -     * It is defined to make the structure to match the layout of
> -     * virtio_net_rss_config structure, defined in 5.1.6.5.7.".
> -     *
> -     * Therefore, we need to zero the fields in struct virtio_net_rss_config,
> -     * which corresponds the `reserved` field in
> -     * struct virtio_net_hash_config.
> -     */
> -    memset(&cfg.indirection_table_mask, 0,
> -           sizeof_field(struct virtio_net_hash_config, reserved));
> +    if (do_rss) {
> +        /*
> +         * According to VirtIO standard, "Number of entries in indirection_table
> +         * is (indirection_table_mask + 1)".
> +         */
> +        cfg.indirection_table_mask = cpu_to_le16(n->rss_data.indirections_len -
> +                                                 1);
> +        cfg.unclassified_queue = cpu_to_le16(n->rss_data.default_queue);
> +        cfg.max_tx_vq = cpu_to_le16(n->curr_queue_pairs);
> +    } else {
> +        /*
> +         * According to VirtIO standard, "Field reserved MUST contain zeroes.
> +         * It is defined to make the structure to match the layout of
> +         * virtio_net_rss_config structure, defined in 5.1.6.5.7.".
> +         *
> +         * Therefore, we need to zero the fields in
> +         * struct virtio_net_rss_config, which corresponds the `reserved` field
> +         * in struct virtio_net_hash_config.
> +         */
> +        memset(&cfg.indirection_table_mask, 0,
> +               sizeof_field(struct virtio_net_hash_config, reserved));
> +    }
>       /*
>        * Consider that virtio_net_handle_rss() currently does not restore the
>        * hash key length parsed from the CVQ command sent from the guest into
> @@ -866,6 +877,7 @@ static int vhost_vdpa_net_load_rss(VhostVDPAState *s, const VirtIONet *n,
>
>       r = vhost_vdpa_net_load_cmd(s, out_cursor, in_cursor,
>                                   VIRTIO_NET_CTRL_MQ,
> +                                do_rss ? VIRTIO_NET_CTRL_MQ_RSS_CONFIG :
>                                   VIRTIO_NET_CTRL_MQ_HASH_CONFIG,
>                                   data, ARRAY_SIZE(data));
>       if (unlikely(r < 0)) {
> @@ -899,13 +911,18 @@ static int vhost_vdpa_net_load_mq(VhostVDPAState *s,
>           return r;
>       }
>
> -    if (!virtio_vdev_has_feature(&n->parent_obj, VIRTIO_NET_F_HASH_REPORT)) {
> -        return 0;
> -    }
> -
> -    r = vhost_vdpa_net_load_rss(s, n, out_cursor, in_cursor, false);
> -    if (unlikely(r < 0)) {
> -        return r;
> +    if (virtio_vdev_has_feature(&n->parent_obj, VIRTIO_NET_F_RSS)) {
> +        /* Load the receive-side scaling state */
> +        r = vhost_vdpa_net_load_rss(s, n, out_cursor, in_cursor, true);
> +        if (unlikely(r < 0)) {
> +            return r;
> +        }
> +    } else if (virtio_vdev_has_feature(&n->parent_obj, VIRTIO_NET_F_RSS)) {

The correct feature to be used here is VIRTIO_NET_F_HASH_REPORT, rather
than VIRTIO_NET_F_RSS. I will correct this in the v2 patch.

Thanks!


> +        /* Load the hash calculation state */
> +        r = vhost_vdpa_net_load_rss(s, n, out_cursor, in_cursor, false);
> +        if (unlikely(r < 0)) {
> +            return r;
> +        }
>       }
>
>       return 0;