Re: [RFC PATCH v8 03/21] vdpa: control virtqueue support on shadow virtqueue

[Jason Wang]

在 2022/5/20 03:12, Eugenio Pérez 写道:
> Introduce the control virtqueue support for vDPA shadow virtqueue. This
> is needed for advanced networking features like multiqueue.
>
> To demonstrate command handling, VIRTIO_NET_F_CTRL_MACADDR and
> VIRTIO_NET_CTRL_MQ are implemented. If vDPA device is started with SVQ
> support and virtio-net driver changes MAC or the number of queues
> virtio-net device model will be updated with the new one.
>
> Others cvq commands could be added here straightforwardly but they have
> been not tested.
>
> Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
> ---
>   net/vhost-vdpa.c | 44 ++++++++++++++++++++++++++++++++++++++++++++
>   1 file changed, 44 insertions(+)
>
> diff --git a/net/vhost-vdpa.c b/net/vhost-vdpa.c
> index df1e69ee72..ef12fc284c 100644
> --- a/net/vhost-vdpa.c
> +++ b/net/vhost-vdpa.c
> @@ -11,6 +11,7 @@
>   
>   #include "qemu/osdep.h"
>   #include "clients.h"
> +#include "hw/virtio/virtio-net.h"
>   #include "net/vhost_net.h"
>   #include "net/vhost-vdpa.h"
>   #include "hw/virtio/vhost-vdpa.h"
> @@ -187,6 +188,46 @@ static NetClientInfo net_vhost_vdpa_info = {
>           .check_peer_type = vhost_vdpa_check_peer_type,
>   };
>   
> +static void vhost_vdpa_net_handle_ctrl(VirtIODevice *vdev,
> +                                       const VirtQueueElement *elem)
> +{
> +    struct virtio_net_ctrl_hdr ctrl;
> +    virtio_net_ctrl_ack status = VIRTIO_NET_ERR;
> +    size_t s;
> +    struct iovec in = {
> +        .iov_base = &status,
> +        .iov_len = sizeof(status),
> +    };
> +
> +    s = iov_to_buf(elem->out_sg, elem->out_num, 0, &ctrl, sizeof(ctrl.class));
> +    if (s != sizeof(ctrl.class)) {
> +        return;
> +    }
> +
> +    switch (ctrl.class) {
> +    case VIRTIO_NET_CTRL_MAC_ADDR_SET:
> +    case VIRTIO_NET_CTRL_MQ:
> +        break;
> +    default:
> +        return;
> +    };


I think we can probably remove the whitelist here since it is expected 
to work for any kind of command?

Thanks


> +
> +    s = iov_to_buf(elem->in_sg, elem->in_num, 0, &status, sizeof(status));
> +    if (s != sizeof(status) || status != VIRTIO_NET_OK) {
> +        return;
> +    }
> +
> +    status = VIRTIO_NET_ERR;
> +    virtio_net_handle_ctrl_iov(vdev, &in, 1, elem->out_sg, elem->out_num);
> +    if (status != VIRTIO_NET_OK) {
> +        error_report("Bad CVQ processing in model");
> +    }
> +}
> +
> +static const VhostShadowVirtqueueOps vhost_vdpa_net_svq_ops = {
> +    .used_elem_handler = vhost_vdpa_net_handle_ctrl,
> +};
> +
>   static NetClientState *net_vhost_vdpa_init(NetClientState *peer,
>                                              const char *device,
>                                              const char *name,
> @@ -211,6 +252,9 @@ static NetClientState *net_vhost_vdpa_init(NetClientState 
> *peer,
>   
>       s->vhost_vdpa.device_fd = vdpa_device_fd;
>       s->vhost_vdpa.index = queue_pair_index;
> +    if (!is_datapath) {
> +        s->vhost_vdpa.shadow_vq_ops = &vhost_vdpa_net_svq_ops;
> +    }
>       ret = vhost_vdpa_add(nc, (void *)&s->vhost_vdpa, queue_pair_index, nvqs);
>       if (ret) {
>           qemu_del_net_client(nc);