[dpdk-dev] [PATCH v11 3/9] net/virtio: add packed virtqueue helpers

[Maxime Coquelin]

On 12/3/18 3:15 PM, Jens Freimann wrote:
> Add helper functions to set/clear and check descriptor flags.
> 
> Signed-off-by: Jens Freimann <jfreimann at redhat.com>
> ---
>   drivers/net/virtio/virtio_ethdev.c |  2 +
>   drivers/net/virtio/virtqueue.h     | 73 +++++++++++++++++++++++++++++-
>   2 files changed, 73 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/net/virtio/virtio_ethdev.c b/drivers/net/virtio/virtio_ethdev.c
> index fdcb7ecaa..48707b7b8 100644
> --- a/drivers/net/virtio/virtio_ethdev.c
> +++ b/drivers/net/virtio/virtio_ethdev.c
> @@ -310,6 +310,7 @@ virtio_init_vring(struct virtqueue *vq)
>   	if (vtpci_packed_queue(vq->hw)) {
>   		vring_init_packed(&vq->ring_packed, ring_mem, VIRTIO_PCI_VRING_ALIGN, size);
>   		vring_desc_init_packed(vq, size);
> +		virtqueue_disable_intr_packed(vq);
>   	} else {
>   		vring_init_split(vr, ring_mem, VIRTIO_PCI_VRING_ALIGN, size);
>   		vring_desc_init_split(vr->desc, size);
> @@ -383,6 +384,7 @@ virtio_init_queue(struct rte_eth_dev *dev, uint16_t vtpci_queue_idx)
>   	vq->hw = hw;
>   	vq->vq_queue_index = vtpci_queue_idx;
>   	vq->vq_nentries = vq_size;
> +	vq->event_flags_shadow = 0;
>   	if (vtpci_packed_queue(hw)) {
>   		vq->avail_wrap_counter = 1;
>   		vq->used_wrap_counter = 1;
> diff --git a/drivers/net/virtio/virtqueue.h b/drivers/net/virtio/virtqueue.h
> index 1401a9844..20b42f5fb 100644
> --- a/drivers/net/virtio/virtqueue.h
> +++ b/drivers/net/virtio/virtqueue.h
> @@ -170,6 +170,7 @@ struct virtqueue {
>   	struct vring_packed ring_packed;  /**< vring keeping desc, used and avail */
>   	bool avail_wrap_counter;
>   	bool used_wrap_counter;
> +	uint16_t event_flags_shadow;

Shouldn't all the above be part of patch 1?
These are not helpers.

>   
>   	/**
>   	 * Last consumed descriptor in the used table,
> @@ -250,6 +251,32 @@ struct virtio_tx_region {
>   			   __attribute__((__aligned__(16)));
>   };
>   
> +static inline void
> +_set_desc_avail(struct vring_packed_desc *desc, int wrap_counter)
> +{
> +	desc->flags |= VRING_DESC_F_AVAIL(wrap_counter) |
> +		       VRING_DESC_F_USED(!wrap_counter);
> +}
> +
> +static inline void
> +set_desc_avail(struct virtqueue *vq, struct vring_packed_desc *desc)
> +{
> +	_set_desc_avail(desc, vq->avail_wrap_counter);
> +}
> +
> +static inline int
> +desc_is_used(struct vring_packed_desc *desc, struct virtqueue *vq)
> +{
> +	uint16_t used, avail, flags;
> +
> +	flags = desc->flags;
> +	used = !!(flags & VRING_DESC_F_USED(1));
> +	avail = !!(flags & VRING_DESC_F_AVAIL(1));
> +
> +	return avail == used && used == vq->used_wrap_counter;
> +}
> +
> +
>   static inline void
>   vring_desc_init_packed(struct virtqueue *vq, int n)
>   {
> @@ -273,22 +300,64 @@ vring_desc_init_split(struct vring_desc *dp, uint16_t n)
>   	dp[i].next = VQ_RING_DESC_CHAIN_END;
>   }
>   
> +/**
> + * Tell the backend not to interrupt us.
> + */
> +static inline void
> +virtqueue_disable_intr_packed(struct virtqueue *vq)
> +{
> +	uint16_t *event_flags = &vq->ring_packed.driver_event->desc_event_flags;
> +
> +	if (*event_flags != RING_EVENT_FLAGS_DISABLE) {
> +		*event_flags = RING_EVENT_FLAGS_DISABLE;
> +	}
> +}
> +
> +
>   /**
>    * Tell the backend not to interrupt us.
>    */
>   static inline void
>   virtqueue_disable_intr(struct virtqueue *vq)
>   {
> -	vq->vq_ring.avail->flags |= VRING_AVAIL_F_NO_INTERRUPT;
> +	if (vtpci_packed_queue(vq->hw))
> +		virtqueue_disable_intr_packed(vq);
> +	else
> +		vq->vq_ring.avail->flags |= VRING_AVAIL_F_NO_INTERRUPT;
> +}
> +
> +/**
> + * Tell the backend to interrupt us.
> + */
> +static inline void
> +virtqueue_enable_intr_packed(struct virtqueue *vq)
> +{
> +	uint16_t *off_wrap = &vq->ring_packed.driver_event->desc_event_off_wrap;
> +	uint16_t *event_flags = &vq->ring_packed.driver_event->desc_event_flags;
> +
> +	*off_wrap = vq->vq_used_cons_idx |
> +		((uint16_t)(vq->used_wrap_counter << 15));
> +
> +	if (vq->event_flags_shadow == RING_EVENT_FLAGS_DISABLE) {
> +		virtio_wmb();
> +		vq->event_flags_shadow =
> +			vtpci_with_feature(vq->hw, VIRTIO_RING_F_EVENT_IDX) ?
> +				RING_EVENT_FLAGS_DESC : RING_EVENT_FLAGS_ENABLE;
> +		*event_flags = vq->event_flags_shadow;
> +	}
>   }
>   
> +
>   /**
>    * Tell the backend to interrupt us.
>    */
>   static inline void
>   virtqueue_enable_intr(struct virtqueue *vq)
>   {
> -	vq->vq_ring.avail->flags &= (~VRING_AVAIL_F_NO_INTERRUPT);
> +	if (vtpci_packed_queue(vq->hw))
> +		virtqueue_enable_intr_packed(vq);
> +	else
> +		vq->vq_ring.avail->flags &= (~VRING_AVAIL_F_NO_INTERRUPT);
>   }
>   
>   /**
>