Re: [PATCH 16/31] vhost: pass queue index to vhost_vq_get_addr

[Jason Wang]

在 2022/1/22 上午4:27, Eugenio Pérez 写道:
> Doing that way allows vhost backend to know what address to return.
>
> Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
> ---
>   hw/virtio/vhost.c | 6 +++---
>   1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/hw/virtio/vhost.c b/hw/virtio/vhost.c
> index 7b03efccec..64b955ba0c 100644
> --- a/hw/virtio/vhost.c
> +++ b/hw/virtio/vhost.c
> @@ -798,9 +798,10 @@ static int vhost_virtqueue_set_addr(struct vhost_dev *dev,
>                                       struct vhost_virtqueue *vq,
>                                       unsigned idx, bool enable_log)
>   {
> -    struct vhost_vring_addr addr;
> +    struct vhost_vring_addr addr = {
> +        .index = idx,
> +    };
>       int r;
> -    memset(&addr, 0, sizeof(struct vhost_vring_addr));
>   
>       if (dev->vhost_ops->vhost_vq_get_addr) {
>           r = dev->vhost_ops->vhost_vq_get_addr(dev, &addr, vq);
> @@ -813,7 +814,6 @@ static int vhost_virtqueue_set_addr(struct vhost_dev *dev,
>           addr.avail_user_addr = (uint64_t)(unsigned long)vq->avail;
>           addr.used_user_addr = (uint64_t)(unsigned long)vq->used;
>       }


I'm a bit lost in the logic above, any reason we need call 
vhost_vq_get_addr() :) ?

Thanks


> -    addr.index = idx;
>       addr.log_guest_addr = vq->used_phys;
>       addr.flags = enable_log ? (1 << VHOST_VRING_F_LOG) : 0;
>       r = dev->vhost_ops->vhost_set_vring_addr(dev, &addr);