Re: [Qemu-devel] [RFC 5/6] virtio-net: steering mode: Implement rss support

[Jason Wang]

On 2018年08月30日 22:27, Sameeh Jubran wrote:
> From: Sameeh Jubran <address@hidden>
>
> Signed-off-by: Sameeh Jubran <address@hidden>
> ---
>   hw/net/virtio-net.c | 122 ++++++++++++++++++++++++++++++++++++++++++++--------
>   1 file changed, 105 insertions(+), 17 deletions(-)
>
> diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
> index e7c4ce6f66..4a52a6a1d0 100644
> --- a/hw/net/virtio-net.c
> +++ b/hw/net/virtio-net.c
> @@ -972,41 +972,129 @@ static int virtio_net_handle_mq(VirtIONet *n, uint8_t 
> cmd,
>       return VIRTIO_NET_OK;
>   }
>   
> -static int virtio_net_ctrl_steering_mode(VirtIONet *n, uint8_t cmd,
> +
> +static int virtio_net_ctrl_sm_rss(VirtIONet *n, uint32_t cmd,
>                                   struct iovec *iov, unsigned int iov_cnt,
>                                   struct iovec *iov_in, unsigned int iov_cnt_in,
> -        size_t *size_in)
> +                                size_t *size_in)
> +{
> +    size_t s;
> +    uint32_t supported_hash_function = 0;
> +
> +    switch (cmd) {
> +    case VIRTIO_NET_SM_CTRL_RSS_GET_SUPPORTED_FUNCTIONS:
> +        supported_hash_function |= RSS_HASH_FUNCTION_TOEPLITZ;
> +        if (!size_in) {
> +            return VIRTIO_NET_ERR;
> +        }
> +        s = iov_from_buf(iov_in, iov_cnt_in, 0,
> +        &supported_hash_function,
> +        supported_hash_function);

Indentation looks wrong.

> +        if (s != sizeof(n->supported_modes) ||
> +        !size_in) {
> +            return VIRTIO_NET_ERR;
> +        }
> +        *size_in = s;
> +        break;
> +    case VIRTIO_NET_SM_CTRL_RSS_SET:
> +        if (!n->rss_conf) {
> +            n->rss_conf = g_malloc0(
> +                    sizeof(struct virtio_net_rss_conf));
> +        } else if (iov == NULL || iov_cnt == 0) {
> +            g_free(n->rss_conf->ptrs.hash_key);
> +            g_free(n->rss_conf->ptrs.indirection_table);
> +            g_free(n->rss_conf);
> +            return VIRTIO_NET_OK;
> +        }
> +        s = iov_to_buf(iov, iov_cnt, 0, n->rss_conf,
> +                sizeof(struct virtio_net_rss_conf) -
> +                sizeof(struct virtio_net_rss_conf_ptrs));
> +
> +        if (s != sizeof(struct virtio_net_rss_conf) -
> +                sizeof(struct virtio_net_rss_conf_ptrs)) {
> +            return VIRTIO_NET_ERR;
> +        }
> +        n->rss_conf->ptrs.hash_key = g_malloc0(sizeof(uint8_t) *
> +                n->rss_conf->hash_key_length);

What happens if n->rss_conf != 0 && iov != NULL? Looks like a guest 
trigger-able OOM?

Btw e.g "conf_ptrs" sounds misleading, why not just embed hash key and 
indirection table pointers directly in rss_conf structure itself?

> +        s = iov_to_buf(iov, iov_cnt, 0, n->rss_conf->ptrs.hash_key,
> +                sizeof(uint8_t) * n->rss_conf->hash_key_length);
> +        if (s != sizeof(uint8_t) * n->rss_conf->hash_key_length) {
> +            g_free(n->rss_conf->ptrs.hash_key);
> +            return VIRTIO_NET_ERR;
> +        }
> +        n->rss_conf->ptrs.indirection_table
> +            = g_malloc0(sizeof(uint32_t) *
> +                    n->rss_conf->indirection_table_length);
> +        s = iov_to_buf(iov, iov_cnt, 0,
> +                n->rss_conf->ptrs.indirection_table, sizeof(uint32_t) *
> +                n->rss_conf->indirection_table_length);
> +        if (s != sizeof(uint32_t) *
> +                n->rss_conf->indirection_table_length) {
> +            g_free(n->rss_conf->ptrs.hash_key);
> +            g_free(n->rss_conf->ptrs.indirection_table);
> +            return VIRTIO_NET_ERR;
> +        }
> +        /* do bpf magic */
> +        break;
> +    default:
> +        return VIRTIO_NET_ERR;
> +    }
> +
> +    return VIRTIO_NET_OK;
> +}
> +
> +static int virtio_net_ctrl_steering_mode(VirtIONet *n, uint8_t cmd,
> +                                struct iovec *iov, unsigned int iov_cnt,
> +                                struct iovec *iov_in, unsigned int iov_in_cnt,
> +                                size_t *size_in)
>   {
>       size_t s;
>       struct virtio_net_steering_mode sm;
> +    int status = 0;
> +    size_t size_in_cmd = 0;
>   
>       switch (cmd) {
>       case VIRTIO_NET_CTRL_SM_GET_SUPPORTED_MODES:
>           if (!size_in) {
>               return VIRTIO_NET_ERR;
>           }
> -                  s = iov_from_buf(iov_in, iov_cnt_in, 0,
> -          &n->supported_modes, sizeof(n->supported_modes));
> +        n->supported_modes.steering_modes |= STEERING_MODE_RSS |
> +            STEERING_MODE_AUTO;

We should have a property for RSS instead of hard coding it here.

Thanks

> +        s = iov_from_buf(iov_in, iov_in_cnt, 0,
> +        &n->supported_modes,
> +        sizeof(n->supported_modes));
>           if (s != sizeof(n->supported_modes) ||
> -          !size_in) {
> +        !size_in) {
>               return VIRTIO_NET_ERR;
>           }
> -                  *size_in = s;
> -      break;
> +        *size_in = s;
> +         break;
>       case VIRTIO_NET_CTRL_SM_CONTROL:
> -        s = iov_to_buf(iov, iov_cnt, 0, &sm, sizeof(sm) -
> -                sizeof(union command_data));
> -        if (s != sizeof(sm) - sizeof(union command_data)) {
> +        s = iov_to_buf(iov, iov_cnt, 0, &sm, sizeof(sm));
> +        if (s != sizeof(sm)) {
> +            return VIRTIO_NET_ERR;
> +        }
> +        iov_discard_front(&iov, &iov_cnt, sizeof(sm));
> +        /* TODO handle the case where we change mode, call the old */
> +        /* mode function with null ptrs  should do the trick of */
> +        /* freeing any resources */
> +        switch (sm.steering_mode) {
> +        case STEERING_MODE_AUTO:
> +                    break;
> +        case STEERING_MODE_RSS:
> +            status = virtio_net_ctrl_sm_rss(n, sm.command,
> +                   iov, iov_cnt, iov_in, iov_in_cnt,
> +                   &size_in_cmd);
> +            if (status == VIRTIO_NET_OK && size_in_cmd > 0) {
> +                *size_in += size_in_cmd;
> +            }
> +            break;
> +        default:
>               return VIRTIO_NET_ERR;
>           }
> -        /* switch (cmd)
> -             {
> -                dafault:
> -                return VIRTIO_NET_ERR;
> -         } */
> -      break;
> +        break;
>       default:
> -                return VIRTIO_NET_ERR;
> +        return VIRTIO_NET_ERR;
>       }
>   
>       return VIRTIO_NET_OK;