[v2,2/6] vhost-user: add op to enable or disable a single vring

There is only vhost_set_dev_enable op in VhostOps. Thus, we introduce
the interface vhost_set_vring_enable to set the enable status for a
single vring.

Resetting a single vq will rely on this interface.

Signed-off-by: Kangjie Xu <kangjie.xu@linux.alibaba.com>
Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
---
 hw/virtio/vhost-user.c            | 25 ++++++++++++++++++-------
 include/hw/virtio/vhost-backend.h |  3 +++
 2 files changed, 21 insertions(+), 7 deletions(-)

在 2022/9/12 11:10, Kangjie Xu 写道:
> There is only vhost_set_dev_enable op in VhostOps. Thus, we introduce
> the interface vhost_set_vring_enable to set the enable status for a
> single vring.
>
> Resetting a single vq will rely on this interface.
>
> Signed-off-by: Kangjie Xu <kangjie.xu@linux.alibaba.com>
> Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>


Acked-by: Jason Wang <jasowang@redhat.com>


> ---
>   hw/virtio/vhost-user.c            | 25 ++++++++++++++++++-------
>   include/hw/virtio/vhost-backend.h |  3 +++
>   2 files changed, 21 insertions(+), 7 deletions(-)
>
> diff --git a/hw/virtio/vhost-user.c b/hw/virtio/vhost-user.c
> index 794519359b..3f140d5085 100644
> --- a/hw/virtio/vhost-user.c
> +++ b/hw/virtio/vhost-user.c
> @@ -1198,6 +1198,22 @@ static int vhost_user_set_vring_base(struct vhost_dev *dev,
>       return vhost_set_vring(dev, VHOST_USER_SET_VRING_BASE, ring);
>   }
>   
> +static int vhost_user_set_vring_enable(struct vhost_dev *dev,
> +                                       int index,
> +                                       int enable)
> +{
> +    if (index < dev->vq_index || index >= dev->vq_index + dev->nvqs) {
> +        return -EINVAL;
> +    }
> +
> +    struct vhost_vring_state state = {
> +        .index = index,
> +        .num   = enable,
> +    };
> +
> +    return vhost_set_vring(dev, VHOST_USER_SET_VRING_ENABLE, &state);
> +}
> +
>   static int vhost_user_set_dev_enable(struct vhost_dev *dev, int enable)
>   {
>       int i;
> @@ -1207,13 +1223,7 @@ static int vhost_user_set_dev_enable(struct vhost_dev *dev, int enable)
>       }
>   
>       for (i = 0; i < dev->nvqs; ++i) {
> -        int ret;
> -        struct vhost_vring_state state = {
> -            .index = dev->vq_index + i,
> -            .num   = enable,
> -        };
> -
> -        ret = vhost_set_vring(dev, VHOST_USER_SET_VRING_ENABLE, &state);
> +        int ret = vhost_user_set_vring_enable(dev, dev->vq_index + i, enable);
>           if (ret < 0) {
>               /*
>                * Restoring the previous state is likely infeasible, as well as
> @@ -2627,6 +2637,7 @@ const VhostOps user_ops = {
>           .vhost_set_owner = vhost_user_set_owner,
>           .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,
>           .vhost_set_dev_enable = vhost_user_set_dev_enable,
>           .vhost_requires_shm_log = vhost_user_requires_shm_log,
>           .vhost_migration_done = vhost_user_migration_done,
> diff --git a/include/hw/virtio/vhost-backend.h b/include/hw/virtio/vhost-backend.h
> index b49432045f..dad7191bac 100644
> --- a/include/hw/virtio/vhost-backend.h
> +++ b/include/hw/virtio/vhost-backend.h
> @@ -81,6 +81,8 @@ 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_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,
> +                                         int index, int enable);
>   typedef int (*vhost_set_dev_enable_op)(struct vhost_dev *dev,
>                                          int enable);
>   typedef bool (*vhost_requires_shm_log_op)(struct vhost_dev *dev);
> @@ -155,6 +157,7 @@ typedef struct VhostOps {
>       vhost_set_owner_op vhost_set_owner;
>       vhost_reset_device_op vhost_reset_device;
>       vhost_get_vq_index_op vhost_get_vq_index;
> +    vhost_set_vring_enable_op vhost_set_vring_enable;
>       vhost_set_dev_enable_op vhost_set_dev_enable;
>       vhost_requires_shm_log_op vhost_requires_shm_log;
>       vhost_migration_done_op vhost_migration_done;