Re: [PATCH v2 2/4] virtio-net: implement RSS configuration command

[Jason Wang <jasowang@redhat.com>]

On 2020/3/9 下午4:34, Yuri Benditovich wrote:
> Optionally report RSS feature.
> Handle RSS configuration command and keep RSS parameters
> in virtio-net device context.
>
> Signed-off-by: Yuri Benditovich <yuri.benditovich@daynix.com>
> ---
>   hw/net/trace-events            |   3 +
>   hw/net/virtio-net.c            | 148 +++++++++++++++++++++++++++++++--
>   include/hw/virtio/virtio-net.h |  11 +++
>   3 files changed, 153 insertions(+), 9 deletions(-)
>
> diff --git a/hw/net/trace-events b/hw/net/trace-events
> index a1da98a643..9823480d91 100644
> --- a/hw/net/trace-events
> +++ b/hw/net/trace-events
> @@ -371,6 +371,9 @@ virtio_net_announce_notify(void) ""
>   virtio_net_announce_timer(int round) "%d"
>   virtio_net_handle_announce(int round) "%d"
>   virtio_net_post_load_device(void)
> +virtio_net_rss_disable(void)
> +virtio_net_rss_error(int error_case) "case %d"
> +virtio_net_rss_enable(uint32_t p1, uint16_t p2, uint8_t p3) "hashes 0x%x, table of %d, key of %d"
>   
>   # tulip.c
>   tulip_reg_write(uint64_t addr, const char *name, int size, uint64_t val) "addr 0x%02"PRIx64" (%s) size %d value 0x%08"PRIx64
> diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
> index 9545b0e84f..27071eccd2 100644
> --- a/hw/net/virtio-net.c
> +++ b/hw/net/virtio-net.c
> @@ -172,6 +172,16 @@ struct virtio_net_rss_config {
>      tso/gso/gro 'off'. */
>   #define VIRTIO_NET_RSC_DEFAULT_INTERVAL 300000
>   
> +#define VIRTIO_NET_RSS_SUPPORTED_HASHES (VIRTIO_NET_RSS_HASH_TYPE_IPv4 | \
> +                                         VIRTIO_NET_RSS_HASH_TYPE_TCPv4 | \
> +                                         VIRTIO_NET_RSS_HASH_TYPE_UDPv4 | \
> +                                         VIRTIO_NET_RSS_HASH_TYPE_IPv6 | \
> +                                         VIRTIO_NET_RSS_HASH_TYPE_TCPv6 | \
> +                                         VIRTIO_NET_RSS_HASH_TYPE_UDPv6 | \
> +                                         VIRTIO_NET_RSS_HASH_TYPE_IP_EX | \
> +                                         VIRTIO_NET_RSS_HASH_TYPE_TCP_EX | \
> +                                         VIRTIO_NET_RSS_HASH_TYPE_UDP_EX)
> +
>   /* temporary until standard header include it */
>   #if !defined(VIRTIO_NET_HDR_F_RSC_INFO)
>   
> @@ -203,6 +213,8 @@ static VirtIOFeature feature_sizes[] = {
>        .end = endof(struct virtio_net_config, mtu)},
>       {.flags = 1ULL << VIRTIO_NET_F_SPEED_DUPLEX,
>        .end = endof(struct virtio_net_config, duplex)},
> +    {.flags = 1ULL << VIRTIO_NET_F_RSS,
> +     .end = endof(struct virtio_net_config, supported_hash_types)},
>       {}
>   };
>   
> @@ -233,6 +245,11 @@ static void virtio_net_get_config(VirtIODevice *vdev, uint8_t *config)
>       memcpy(netcfg.mac, n->mac, ETH_ALEN);
>       virtio_stl_p(vdev, &netcfg.speed, n->net_conf.speed);
>       netcfg.duplex = n->net_conf.duplex;
> +    netcfg.rss_max_key_size = VIRTIO_NET_RSS_MAX_KEY_SIZE;
> +    virtio_stw_p(vdev, &netcfg.rss_max_indirection_table_length,
> +                 VIRTIO_NET_RSS_MAX_TABLE_LEN);
> +    virtio_stl_p(vdev, &netcfg.supported_hash_types,
> +                 VIRTIO_NET_RSS_SUPPORTED_HASHES);
>       memcpy(config, &netcfg, n->config_size);
>   }
>   
> @@ -796,6 +813,7 @@ static uint64_t virtio_net_get_features(VirtIODevice *vdev, uint64_t features,
>           return features;
>       }
>   
> +    virtio_clear_feature(&features, VIRTIO_NET_F_RSS);
>       features = vhost_net_get_features(get_vhost_net(nc->peer), features);
>       vdev->backend_features = features;
>   
> @@ -955,6 +973,7 @@ static void virtio_net_set_features(VirtIODevice *vdev, uint64_t features)
>       }
>   
>       virtio_net_set_multiqueue(n,
> +                              virtio_has_feature(features, VIRTIO_NET_F_RSS) ||
>                                 virtio_has_feature(features, VIRTIO_NET_F_MQ));
>   
>       virtio_net_set_mrg_rx_bufs(n,
> @@ -1231,25 +1250,134 @@ static int virtio_net_handle_announce(VirtIONet *n, uint8_t cmd,
>       }
>   }
>   
> +static void virtio_net_disable_rss(VirtIONet *n)
> +{
> +    if (n->rss_data.enabled) {
> +        trace_virtio_net_rss_disable();
> +    }
> +    n->rss_data.enabled = false;
> +}
> +
> +static uint16_t virtio_net_handle_rss(VirtIONet *n,
> +                                      struct iovec *iov, unsigned int iov_cnt)
> +{
> +    VirtIODevice *vdev = VIRTIO_DEVICE(n);
> +    struct virtio_net_rss_config cfg;
> +    size_t s, offset = 0, size_get;
> +    uint16_t queues, i;
> +    struct {
> +        uint16_t us;
> +        uint8_t b;
> +    } QEMU_PACKED temp;
> +    int err;
> +
> +    if (!virtio_vdev_has_feature(vdev, VIRTIO_NET_F_RSS)) {
> +        err = 1;
> +        goto error;
> +    }
> +    size_get = offsetof(struct virtio_net_rss_config, indirection_table);
> +    s = iov_to_buf(iov, iov_cnt, offset, &cfg, size_get);
> +    if (s != size_get) {
> +        err = 2;
> +        goto error;
> +    }
> +    n->rss_data.hash_types = virtio_ldl_p(vdev, &cfg.hash_types);
> +    n->rss_data.indirections_len =
> +        virtio_lduw_p(vdev, &cfg.indirection_table_mask);
> +    n->rss_data.indirections_len++;
> +    if (!is_power_of_2(n->rss_data.indirections_len)) {
> +        err = 3;
> +        goto error;
> +    }
> +    if (n->rss_data.indirections_len > VIRTIO_NET_RSS_MAX_TABLE_LEN) {
> +        err = 4;
> +        goto error;
> +    }
> +    n->rss_data.default_queue =
> +        virtio_lduw_p(vdev, &cfg.unclassified_queue);
> +    if (n->rss_data.default_queue >= n->max_queues) {
> +        err = 5;
> +        goto error;
> +    }
> +    offset += size_get;
> +    size_get = sizeof(uint16_t) * n->rss_data.indirections_len;
> +    s = iov_to_buf(iov, iov_cnt, offset, n->rss_data.indirections, size_get);
> +    if (s != size_get) {
> +        err = 10;
> +        goto error;
> +    }
> +    for (i = 0; i < n->rss_data.indirections_len; ++i) {
> +        uint16_t val = n->rss_data.indirections[i];
> +        n->rss_data.indirections[i] = virtio_lduw_p(vdev, &val);
> +    }
> +    offset += size_get;
> +    size_get = sizeof(temp);
> +    s = iov_to_buf(iov, iov_cnt, offset, &temp, size_get);
> +    if (s != size_get) {
> +        err = 11;
> +        goto error;
> +    }
> +    queues = virtio_lduw_p(vdev, &temp.us);
> +    if (queues == 0 || queues > n->max_queues) {
> +        err = 12;
> +        goto error;
> +    }
> +    if (temp.b > VIRTIO_NET_RSS_MAX_KEY_SIZE) {
> +        err = 13;
> +        goto error;
> +    }
> +    if (!temp.b && n->rss_data.hash_types) {
> +        err = 20;
> +        goto error;
> +    }
> +    if (!temp.b && !n->rss_data.hash_types) {
> +        virtio_net_disable_rss(n);
> +        return queues;
> +    }
> +    offset += size_get;
> +    size_get = temp.b;
> +    s = iov_to_buf(iov, iov_cnt, offset, n->rss_data.key, size_get);
> +    if (s != size_get) {
> +        err = 21;
> +        goto error;
> +    }
> +    n->rss_data.enabled = true;
> +    trace_virtio_net_rss_enable(n->rss_data.hash_types,
> +                                n->rss_data.indirections_len,
> +                                temp.b);
> +    return queues;
> +error:
> +    warn_report("%s: error_case %d", __func__, err);


I'm not sure using warn_report() is good for such guest triggerable 
behavior.


> +    trace_virtio_net_rss_error(err);


It looks to me it would be better to be verbose here (show temp.b or other)


> +    virtio_net_disable_rss(n);
> +    return 0;
> +}
> +
>   static int virtio_net_handle_mq(VirtIONet *n, uint8_t cmd,
>                                   struct iovec *iov, unsigned int iov_cnt)
>   {
>       VirtIODevice *vdev = VIRTIO_DEVICE(n);
> -    struct virtio_net_ctrl_mq mq;
> -    size_t s;
>       uint16_t queues;
>   
> -    s = iov_to_buf(iov, iov_cnt, 0, &mq, sizeof(mq));
> -    if (s != sizeof(mq)) {
> -        return VIRTIO_NET_ERR;
> -    }
> +    virtio_net_disable_rss(n);
> +    if (cmd == VIRTIO_NET_CTRL_MQ_RSS_CONFIG) {
> +        queues = virtio_net_handle_rss(n, iov, iov_cnt);
> +    } else if (cmd == VIRTIO_NET_CTRL_MQ_VQ_PAIRS_SET) {


It looks to me RSS and MQ are mutually exclusive, is this intentional?


> +        struct virtio_net_ctrl_mq mq;
> +        size_t s;
> +        if (!virtio_vdev_has_feature(vdev, VIRTIO_NET_F_MQ)) {
> +            return VIRTIO_NET_ERR;
> +        }
> +        s = iov_to_buf(iov, iov_cnt, 0, &mq, sizeof(mq));
> +        if (s != sizeof(mq)) {
> +            return VIRTIO_NET_ERR;
> +        }
> +        queues = virtio_lduw_p(vdev, &mq.virtqueue_pairs);
>   
> -    if (cmd != VIRTIO_NET_CTRL_MQ_VQ_PAIRS_SET) {
> +    } else {
>           return VIRTIO_NET_ERR;
>       }
>   
> -    queues = virtio_lduw_p(vdev, &mq.virtqueue_pairs);
> -
>       if (queues < VIRTIO_NET_CTRL_MQ_VQ_PAIRS_MIN ||
>           queues > VIRTIO_NET_CTRL_MQ_VQ_PAIRS_MAX ||
>           queues > n->max_queues ||
> @@ -3304,6 +3432,8 @@ static Property virtio_net_properties[] = {
>       DEFINE_PROP_BIT64("ctrl_guest_offloads", VirtIONet, host_features,
>                       VIRTIO_NET_F_CTRL_GUEST_OFFLOADS, true),
>       DEFINE_PROP_BIT64("mq", VirtIONet, host_features, VIRTIO_NET_F_MQ, false),
> +    DEFINE_PROP_BIT64("rss", VirtIONet, host_features,
> +                    VIRTIO_NET_F_RSS, false),
>       DEFINE_PROP_BIT64("guest_rsc_ext", VirtIONet, host_features,
>                       VIRTIO_NET_F_RSC_EXT, false),
>       DEFINE_PROP_UINT32("rsc_interval", VirtIONet, rsc_timeout,
> diff --git a/include/hw/virtio/virtio-net.h b/include/hw/virtio/virtio-net.h
> index 96c68d4a92..cf16f5192e 100644
> --- a/include/hw/virtio/virtio-net.h
> +++ b/include/hw/virtio/virtio-net.h
> @@ -126,6 +126,9 @@ typedef struct VirtioNetRscChain {
>   /* Maximum packet size we can receive from tap device: header + 64k */
>   #define VIRTIO_NET_MAX_BUFSIZE (sizeof(struct virtio_net_hdr) + (64 * KiB))
>   
> +#define VIRTIO_NET_RSS_MAX_KEY_SIZE     40
> +#define VIRTIO_NET_RSS_MAX_TABLE_LEN    128
> +
>   typedef struct VirtIONetQueue {
>       VirtQueue *rx_vq;
>       VirtQueue *tx_vq;
> @@ -199,6 +202,14 @@ struct VirtIONet {
>       bool failover;
>       DeviceListener primary_listener;
>       Notifier migration_state;
> +    struct {
> +        bool    enabled;
> +        uint32_t hash_types;
> +        uint8_t key[VIRTIO_NET_RSS_MAX_KEY_SIZE];
> +        uint16_t indirections[VIRTIO_NET_RSS_MAX_TABLE_LEN];
> +        uint16_t indirections_len;
> +        uint16_t default_queue;
> +    } rss_data;
>   };
>   
>   void virtio_net_set_netclient_name(VirtIONet *n, const char *name,