Re: [PATCH v2 14/24] vhost-user: introduce vhost_reset_vring() interface

[Jason Wang]

在 2022/8/16 09:06, Kangjie Xu 写道:
> Introduce the interface vhost_reset_vring(). The interface is a wrapper
> to send a VHOST_USER_RESET_VRING message to the back-end. It will reset
> an individual vring in the back-end. Meanwhile, it will wait for a reply
> to ensure the reset has been completed.
>
> Signed-off-by: Kangjie Xu <kangjie.xu@linux.alibaba.com>
> Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
> ---
>   hw/virtio/vhost-user.c            | 41 +++++++++++++++++++++++++++++++
>   include/hw/virtio/vhost-backend.h |  3 +++
>   2 files changed, 44 insertions(+)
>
> diff --git a/hw/virtio/vhost-user.c b/hw/virtio/vhost-user.c
> index 75b8df21a4..56033f7a92 100644
> --- a/hw/virtio/vhost-user.c
> +++ b/hw/virtio/vhost-user.c
> @@ -126,6 +126,7 @@ typedef enum VhostUserRequest {
>       VHOST_USER_GET_MAX_MEM_SLOTS = 36,
>       VHOST_USER_ADD_MEM_REG = 37,
>       VHOST_USER_REM_MEM_REG = 38,
> +    VHOST_USER_RESET_VRING = 41,
>       VHOST_USER_MAX
>   } VhostUserRequest;
>   
> @@ -1498,6 +1499,45 @@ static int vhost_user_get_max_memslots(struct vhost_dev *dev,
>       return 0;
>   }
>   
> +static int vhost_user_reset_vring(struct vhost_dev *dev,
> +                                  struct vhost_vring_state *ring)
> +{
> +    int ret;
> +    VhostUserMsg msg = {
> +        .hdr.request = VHOST_USER_RESET_VRING,
> +        .hdr.flags = VHOST_USER_VERSION,


Do we need VHOST_USER_NEED_REPLY_MASK here?

Other looks good.

Thanks


> +        .payload.state = *ring,
> +        .hdr.size = sizeof(msg.payload.state),
> +    };
> +
> +    if (!virtio_has_feature(dev->acked_features, VIRTIO_F_RING_RESET)) {
> +        return -ENOTSUP;
> +    }
> +
> +    ret = vhost_user_write(dev, &msg, NULL, 0);
> +    if (ret < 0) {
> +        return ret;
> +    }
> +
> +    ret = vhost_user_read(dev, &msg);
> +    if (ret < 0) {
> +        return ret;
> +    }
> +
> +    if (msg.hdr.request != VHOST_USER_RESET_VRING) {
> +        error_report("Received unexpected msg type. Expected %d received %d",
> +                     VHOST_USER_RESET_VRING, msg.hdr.request);
> +        return -EPROTO;
> +    }
> +
> +    if (msg.hdr.size != sizeof(msg.payload.state)) {
> +        error_report("Received bad msg size.");
> +        return -EPROTO;
> +    }
> +
> +    return 0;
> +}
> +
>   static int vhost_user_reset_device(struct vhost_dev *dev)
>   {
>       VhostUserMsg msg = {
> @@ -2625,6 +2665,7 @@ const VhostOps user_ops = {
>           .vhost_set_features = vhost_user_set_features,
>           .vhost_get_features = vhost_user_get_features,
>           .vhost_set_owner = vhost_user_set_owner,
> +        .vhost_reset_vring = vhost_user_reset_vring,
>           .vhost_reset_device = vhost_user_reset_device,
>           .vhost_get_vq_index = vhost_user_get_vq_index,
>           .vhost_set_vring_enable = vhost_user_set_vring_enable,
> diff --git a/include/hw/virtio/vhost-backend.h 
> b/include/hw/virtio/vhost-backend.h
> index eab46d7f0b..f23bf71a8d 100644
> --- a/include/hw/virtio/vhost-backend.h
> +++ b/include/hw/virtio/vhost-backend.h
> @@ -79,6 +79,8 @@ typedef int (*vhost_get_features_op)(struct vhost_dev *dev,
>                                        uint64_t *features);
>   typedef int (*vhost_set_backend_cap_op)(struct vhost_dev *dev);
>   typedef int (*vhost_set_owner_op)(struct vhost_dev *dev);
> +typedef int (*vhost_reset_vring_op)(struct vhost_dev *dev,
> +                                    struct vhost_vring_state *ring);
>   typedef int (*vhost_reset_device_op)(struct vhost_dev *dev);
>   typedef int (*vhost_get_vq_index_op)(struct vhost_dev *dev, int idx);
>   typedef int (*vhost_set_vring_enable_op)(struct vhost_dev *dev,
> @@ -154,6 +156,7 @@ typedef struct VhostOps {
>       vhost_set_backend_cap_op vhost_set_backend_cap;
>       vhost_set_owner_op vhost_set_owner;
>       vhost_reset_device_op vhost_reset_device;
> +    vhost_reset_vring_op vhost_reset_vring;
>       vhost_get_vq_index_op vhost_get_vq_index;
>       vhost_set_vring_enable_op vhost_set_vring_enable;
>       vhost_requires_shm_log_op vhost_requires_shm_log;