Re: [PATCH v5 15/15] vdpa: Add x-svq to NetdevVhostVDPAOptions

["Michael S. Tsirkin" <mst@redhat.com>]

On Mon, Mar 07, 2022 at 04:33:34PM +0100, Eugenio Pérez wrote:
> Finally offering the possibility to enable SVQ from the command line.
> 
> Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
> ---
>  qapi/net.json    |  8 +++++++-
>  net/vhost-vdpa.c | 48 ++++++++++++++++++++++++++++++++++++++++--------
>  2 files changed, 47 insertions(+), 9 deletions(-)
> 
> diff --git a/qapi/net.json b/qapi/net.json
> index 7fab2e7cd8..d626fa441c 100644
> --- a/qapi/net.json
> +++ b/qapi/net.json
> @@ -445,12 +445,18 @@
>  # @queues: number of queues to be created for multiqueue vhost-vdpa
>  #          (default: 1)
>  #
> +# @svq: Start device with (experimental) shadow virtqueue. (Since 7.0)
> +#
> +# Features:
> +# @unstable: Member @svq is experimental.
> +#
>  # Since: 5.1
>  ##
>  { 'struct': 'NetdevVhostVDPAOptions',
>    'data': {
>      '*vhostdev':     'str',
> -    '*queues':       'int' } }
> +    '*queues':       'int',
> +    '*svq':          {'type': 'bool', 'features' : [ 'unstable'] } } }
>  
>  ##
>  # @NetClientDriver:

I think this should be x-svq same as other unstable features.

> diff --git a/net/vhost-vdpa.c b/net/vhost-vdpa.c
> index 1e9fe47c03..c827921654 100644
> --- a/net/vhost-vdpa.c
> +++ b/net/vhost-vdpa.c
> @@ -127,7 +127,11 @@ err_init:
>  static void vhost_vdpa_cleanup(NetClientState *nc)
>  {
>      VhostVDPAState *s = DO_UPCAST(VhostVDPAState, nc, nc);
> +    struct vhost_dev *dev = s->vhost_vdpa.dev;
>  
> +    if (dev && dev->vq_index + dev->nvqs == dev->vq_index_end) {
> +        g_clear_pointer(&s->vhost_vdpa.iova_tree, vhost_iova_tree_delete);
> +    }
>      if (s->vhost_net) {
>          vhost_net_cleanup(s->vhost_net);
>          g_free(s->vhost_net);
> @@ -187,13 +191,23 @@ static NetClientInfo net_vhost_vdpa_info = {
>          .check_peer_type = vhost_vdpa_check_peer_type,
>  };
>  
> +static int vhost_vdpa_get_iova_range(int fd,
> +                                     struct vhost_vdpa_iova_range *iova_range)
> +{
> +    int ret = ioctl(fd, VHOST_VDPA_GET_IOVA_RANGE, iova_range);
> +
> +    return ret < 0 ? -errno : 0;
> +}
> +
>  static NetClientState *net_vhost_vdpa_init(NetClientState *peer,
> -                                           const char *device,
> -                                           const char *name,
> -                                           int vdpa_device_fd,
> -                                           int queue_pair_index,
> -                                           int nvqs,
> -                                           bool is_datapath)
> +                                       const char *device,
> +                                       const char *name,
> +                                       int vdpa_device_fd,
> +                                       int queue_pair_index,
> +                                       int nvqs,
> +                                       bool is_datapath,
> +                                       bool svq,
> +                                       VhostIOVATree *iova_tree)
>  {
>      NetClientState *nc = NULL;
>      VhostVDPAState *s;
> @@ -211,6 +225,8 @@ static NetClientState *net_vhost_vdpa_init(NetClientState *peer,
>  
>      s->vhost_vdpa.device_fd = vdpa_device_fd;
>      s->vhost_vdpa.index = queue_pair_index;
> +    s->vhost_vdpa.shadow_vqs_enabled = svq;
> +    s->vhost_vdpa.iova_tree = iova_tree;
>      ret = vhost_vdpa_add(nc, (void *)&s->vhost_vdpa, queue_pair_index, nvqs);
>      if (ret) {
>          qemu_del_net_client(nc);
> @@ -266,6 +282,7 @@ int net_init_vhost_vdpa(const Netdev *netdev, const char *name,
>      g_autofree NetClientState **ncs = NULL;
>      NetClientState *nc;
>      int queue_pairs, i, has_cvq = 0;
> +    g_autoptr(VhostIOVATree) iova_tree = NULL;
>  
>      assert(netdev->type == NET_CLIENT_DRIVER_VHOST_VDPA);
>      opts = &netdev->u.vhost_vdpa;
> @@ -285,29 +302,44 @@ int net_init_vhost_vdpa(const Netdev *netdev, const char *name,
>          qemu_close(vdpa_device_fd);
>          return queue_pairs;
>      }
> +    if (opts->svq) {
> +        struct vhost_vdpa_iova_range iova_range;
> +
> +        if (has_cvq) {
> +            error_setg(errp, "vdpa svq does not work with cvq");
> +            goto err_svq;
> +        }
> +        vhost_vdpa_get_iova_range(vdpa_device_fd, &iova_range);
> +        iova_tree = vhost_iova_tree_new(iova_range.first, iova_range.last);
> +    }
>  
>      ncs = g_malloc0(sizeof(*ncs) * queue_pairs);
>  
>      for (i = 0; i < queue_pairs; i++) {
>          ncs[i] = net_vhost_vdpa_init(peer, TYPE_VHOST_VDPA, name,
> -                                     vdpa_device_fd, i, 2, true);
> +                                     vdpa_device_fd, i, 2, true, opts->svq,
> +                                     iova_tree);
>          if (!ncs[i])
>              goto err;
>      }
>  
>      if (has_cvq) {
>          nc = net_vhost_vdpa_init(peer, TYPE_VHOST_VDPA, name,
> -                                 vdpa_device_fd, i, 1, false);
> +                                 vdpa_device_fd, i, 1, false, opts->svq,
> +                                 iova_tree);
>          if (!nc)
>              goto err;
>      }
>  
> +    iova_tree = NULL;
>      return 0;
>  
>  err:
>      if (i) {
>          qemu_del_net_client(ncs[0]);
>      }
> +
> +err_svq:
>      qemu_close(vdpa_device_fd);
>  
>      return -1;
> -- 
> 2.27.0

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