Re: [RFC 05/10] vhost: Add vhost_dev_from_virtio

[Jason Wang <jasowang@redhat.com>]

On 2021/1/30 上午4:54, Eugenio Pérez wrote:
> Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
> ---
>   include/hw/virtio/vhost.h |  1 +
>   hw/virtio/vhost.c         | 17 +++++++++++++++++
>   2 files changed, 18 insertions(+)
>
> diff --git a/include/hw/virtio/vhost.h b/include/hw/virtio/vhost.h
> index 4a8bc75415..fca076e3f0 100644
> --- a/include/hw/virtio/vhost.h
> +++ b/include/hw/virtio/vhost.h
> @@ -123,6 +123,7 @@ uint64_t vhost_get_features(struct vhost_dev *hdev, const int *feature_bits,
>   void vhost_ack_features(struct vhost_dev *hdev, const int *feature_bits,
>                           uint64_t features);
>   bool vhost_has_free_slot(void);
> +struct vhost_dev *vhost_dev_from_virtio(const VirtIODevice *vdev);
>   
>   int vhost_net_set_backend(struct vhost_dev *hdev,
>                             struct vhost_vring_file *file);
> diff --git a/hw/virtio/vhost.c b/hw/virtio/vhost.c
> index 28c7d78172..8683d507f5 100644
> --- a/hw/virtio/vhost.c
> +++ b/hw/virtio/vhost.c
> @@ -61,6 +61,23 @@ bool vhost_has_free_slot(void)
>       return slots_limit > used_memslots;
>   }
>   
> +/*
> + * Get the vhost device associated to a VirtIO device.
> + */
> +struct vhost_dev *vhost_dev_from_virtio(const VirtIODevice *vdev)
> +{
> +    struct vhost_dev *hdev;
> +
> +    QLIST_FOREACH(hdev, &vhost_devices, entry) {
> +        if (hdev->vdev == vdev) {
> +            return hdev;
> +        }
> +    }
> +
> +    assert(hdev);
> +    return NULL;
> +}


I'm not sure this can work in the case of multiqueue. E.g vhost-net 
multiqueue is a N:1 mapping between vhost devics and virtio devices.

Thanks


> +
>   static void vhost_dev_sync_region(struct vhost_dev *dev,
>                                     MemoryRegionSection *section,
>                                     uint64_t mfirst, uint64_t mlast,