[dpdk-dev] [PATCH v3 13/21] vhost: add helpers for packed virtqueues

Maxime Coquelin maxime.coquelin at redhat.com
Fri Apr 6 11:20:10 CEST 2018



On 04/05/2018 12:10 PM, Jens Freimann wrote:
> Add some helper functions to set/check descriptor flags
> and toggle the used wrap counter.
> 
> Signed-off-by: Jens Freimann <jfreimann at redhat.com>
> ---
>   lib/librte_vhost/virtio-1.1.h | 44 +++++++++++++++++++++++++++++++++++++++++++
>   1 file changed, 44 insertions(+)
> 
> diff --git a/lib/librte_vhost/virtio-1.1.h b/lib/librte_vhost/virtio-1.1.h
> index 7b48caed7..e77d7aa6c 100644
> --- a/lib/librte_vhost/virtio-1.1.h
> +++ b/lib/librte_vhost/virtio-1.1.h
Shouldn't the file be named virtio-packed.h?

> @@ -15,4 +15,48 @@ struct vring_desc_packed {
>   	uint16_t flags;
>   };
>   
> +static inline void
> +toggle_wrap_counter(struct vhost_virtqueue *vq)
> +{
> +	vq->used_wrap_counter ^= 1;
> +}
> +
> +static inline int
> +desc_is_avail(struct vhost_virtqueue *vq, struct vring_desc_packed *desc)
> +{
> +	if (vq->used_wrap_counter == 1) {
> +		if ((desc->flags & VRING_DESC_F_AVAIL) &&
> +				!(desc->flags & VRING_DESC_F_USED))
> +			return 1;
> +	}
> +	if (vq->used_wrap_counter == 0) {
> +		if (!(desc->flags & VRING_DESC_F_AVAIL) &&
> +				(desc->flags & VRING_DESC_F_USED))
> +			return 1;
> +	}
> +	return 0;
> +}
> +
> +static inline void
> +_set_desc_used(struct vring_desc_packed *desc, int wrap_counter)
> +{
> +	uint16_t flags = desc->flags;
> +
> +	if (wrap_counter == 1) {
> +		flags |= VRING_DESC_F_USED;
> +		flags |= VRING_DESC_F_AVAIL;
> +	} else {
> +		flags &= ~VRING_DESC_F_USED;
> +		flags &= ~VRING_DESC_F_AVAIL;
> +	}
> +
> +	desc->flags = flags;
> +}
> +
> +static inline void
> +set_desc_used(struct vhost_virtqueue *vq, struct vring_desc_packed *desc)
> +{
> +	_set_desc_used(desc, vq->used_wrap_counter);
> +}
> +

Maybe prefix all with vring_
>   #endif /* __VIRTIO_PACKED_H */
> 


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