On Sun, Oct 22, 2023 at 10:00:48AM +0800, Hawkins Jiawei wrote:
> This patch introduces vhost_vdpa_net_load_rss() to restore
> the hash calculation state at device's startup.
>
> Signed-off-by: Hawkins Jiawei <yin31...@gmail.com>
> ---
> v3:
> - remove the `do_rss` argument in vhost_vdpa_net_load_rss()
> - zero reserved fields in "cfg" manually instead of using memset()
> to prevent compiler "array-bounds" warning
>
> v2:
> https://lore.kernel.org/all/f5ffad10699001107022851e0560cb394039d6b0.1693297766.git.yin31...@gmail.com/
> - resolve conflict with updated patch
> "vdpa: Send all CVQ state load commands in parallel"
> - move the `table` declaration at the beginning of the
> vhost_vdpa_net_load_rss()
>
> RFC:
> https://lore.kernel.org/all/a54ca70b12ebe2f3c391864e41241697ab1aba30.1691762906.git.yin31...@gmail.com/
>
> net/vhost-vdpa.c | 89 ++++++++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 89 insertions(+)
>
> diff --git a/net/vhost-vdpa.c b/net/vhost-vdpa.c
> index 4b7c3b81b8..2e4bad65b4 100644
> --- a/net/vhost-vdpa.c
> +++ b/net/vhost-vdpa.c
> @@ -817,6 +817,86 @@ static int vhost_vdpa_net_load_mac(VhostVDPAState *s,
> const VirtIONet *n,
> return 0;
> }
>
> +static int vhost_vdpa_net_load_rss(VhostVDPAState *s, const VirtIONet *n,
> + struct iovec *out_cursor,
> + struct iovec *in_cursor)
> +{
> + struct virtio_net_rss_config cfg;
> + ssize_t r;
> + g_autofree uint16_t *table = NULL;
> +
> + /*
> + * According to VirtIO standard, "Initially the device has all hash
> + * types disabled and reports only VIRTIO_NET_HASH_REPORT_NONE.".
> + *
> + * Therefore, there is no need to send this CVQ command if the
> + * driver disable the all hash types, which aligns with
disables? or disabled
> + * the device's defaults.
> + *
> + * Note that the device's defaults can mismatch the driver's
> + * configuration only at live migration.
> + */
> + if (!n->rss_data.enabled ||
> + n->rss_data.hash_types == VIRTIO_NET_HASH_REPORT_NONE) {
> + return 0;
> + }
> +
> + table = g_malloc_n(n->rss_data.indirections_len,
> + sizeof(n->rss_data.indirections_table[0]));
> + 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
corresponds to
> + * struct virtio_net_hash_config.
> + */
> + cfg.indirection_table_mask = 0;
> + cfg.unclassified_queue = 0;
> + table[0] = 0; /* the actual indirection table for cfg */
> + cfg.max_tx_vq = 0;
Wouldn't it be easier to just do cfg = {} where it is defined?
> +
> + /*
> + * Consider that virtio_net_handle_rss() currently does not restore the
> + * hash key length parsed from the CVQ command sent from the guest into
> + * n->rss_data and uses the maximum key length in other code, so we also
> + * employthe the maxium key length here.
two typos
> + */
> + cfg.hash_key_length = sizeof(n->rss_data.key);
> +
> + const struct iovec data[] = {
> + {
> + .iov_base = &cfg,
> + .iov_len = offsetof(struct virtio_net_rss_config,
> + indirection_table),
> + }, {
> + .iov_base = table,
> + .iov_len = n->rss_data.indirections_len *
> + sizeof(n->rss_data.indirections_table[0]),
> + }, {
> + .iov_base = &cfg.max_tx_vq,
> + .iov_len = offsetof(struct virtio_net_rss_config, hash_key_data)
> -
> + offsetof(struct virtio_net_rss_config, max_tx_vq),
> + }, {
> + .iov_base = (void *)n->rss_data.key,
cast to void * should not be needed here.
> + .iov_len = sizeof(n->rss_data.key),
> + }
> + };
> +
> + r = vhost_vdpa_net_load_cmd(s, out_cursor, in_cursor,
> + VIRTIO_NET_CTRL_MQ,
> + VIRTIO_NET_CTRL_MQ_HASH_CONFIG,
> + data, ARRAY_SIZE(data));
> + if (unlikely(r < 0)) {
> + return r;
> + }
> +
> + return 0;
> +}
> +
> static int vhost_vdpa_net_load_mq(VhostVDPAState *s,
> const VirtIONet *n,
> struct iovec *out_cursor,
> @@ -842,6 +922,15 @@ 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);
> + if (unlikely(r < 0)) {
> + return r;
> + }
> +
> return 0;
> }
>
> --
> 2.25.1
