[dpdk-dev] [PATCH v2 1/2] net/virtio-user: ctrl vq support for packed

[Maxime Coquelin]

On 1/10/19 2:17 PM, Jens Freimann wrote:
> Add support to virtio-user for control virtqueues.
> 
> Signed-off-by: Jens Freimann <jfreimann at redhat.com>
> ---
>   .../net/virtio/virtio_user/virtio_user_dev.c  | 92 ++++++++++++++++++-
>   .../net/virtio/virtio_user/virtio_user_dev.h  |  8 +-
>   drivers/net/virtio/virtio_user_ethdev.c       | 49 +++++++++-
>   3 files changed, 141 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/net/virtio/virtio_user/virtio_user_dev.c b/drivers/net/virtio/virtio_user/virtio_user_dev.c
> index b9044faff..49fcf48b9 100644
> --- a/drivers/net/virtio/virtio_user/virtio_user_dev.c
> +++ b/drivers/net/virtio/virtio_user/virtio_user_dev.c
> @@ -43,15 +43,26 @@ virtio_user_kick_queue(struct virtio_user_dev *dev, uint32_t queue_sel)
>   	struct vhost_vring_file file;
>   	struct vhost_vring_state state;
>   	struct vring *vring = &dev->vrings[queue_sel];
> +	struct vring_packed *pq_vring = &dev->packed_vrings[queue_sel];
>   	struct vhost_vring_addr addr = {
>   		.index = queue_sel,
> -		.desc_user_addr = (uint64_t)(uintptr_t)vring->desc,
> -		.avail_user_addr = (uint64_t)(uintptr_t)vring->avail,
> -		.used_user_addr = (uint64_t)(uintptr_t)vring->used,
>   		.log_guest_addr = 0,
>   		.flags = 0, /* disable log */
>   	};
>   
> +	if (dev->features & (1ULL << VIRTIO_F_RING_PACKED)) {
> +		addr.desc_user_addr =
> +			(uint64_t)(uintptr_t)pq_vring->desc_packed;
> +		addr.avail_user_addr =
> +			(uint64_t)(uintptr_t)pq_vring->driver_event;
> +		addr.used_user_addr =
> +			(uint64_t)(uintptr_t)pq_vring->device_event;
> +	} else {
> +		addr.desc_user_addr = (uint64_t)(uintptr_t)vring->desc;
> +		addr.avail_user_addr = (uint64_t)(uintptr_t)vring->avail;
> +		addr.used_user_addr = (uint64_t)(uintptr_t)vring->used;
> +	}
> +
>   	state.index = queue_sel;
>   	state.num = vring->num;
>   	dev->ops->send_request(dev, VHOST_USER_SET_VRING_NUM, &state);
> @@ -620,6 +631,81 @@ virtio_user_handle_ctrl_msg(struct virtio_user_dev *dev, struct vring *vring,
>   	return n_descs;
>   }
>   
> +static inline int
> +desc_is_avail(struct vring_packed_desc *desc, bool wrap_counter)
> +{
> +	return wrap_counter == !!(desc->flags & VRING_DESC_F_AVAIL(1)) &&
> +		wrap_counter != !!(desc->flags & VRING_DESC_F_USED(1));
> +}
> +
> +static uint32_t
> +virtio_user_handle_ctrl_msg_pq(struct virtio_user_dev *dev,
> +			    struct vring_packed *vring,
> +			    uint16_t idx_hdr)
> +{
> +	struct virtio_net_ctrl_hdr *hdr;
> +	virtio_net_ctrl_ack status = ~0;
> +	uint16_t idx_data, idx_status;
> +	/* initialize to one, header is first */
> +	uint32_t n_descs = 1;
> +
> +	/* locate desc for header, data, and status */
> +	idx_data = idx_hdr + 1;
> +	n_descs++;
> +
> +	idx_status = idx_data;
> +	while (vring->desc_packed[idx_status].flags & VRING_DESC_F_NEXT) {
> +		idx_status++;
> +		n_descs++;
> +	}
> +
> +	hdr = (void *)(uintptr_t)vring->desc_packed[idx_hdr].addr;
> +	if (hdr->class == VIRTIO_NET_CTRL_MQ &&
> +	    hdr->cmd == VIRTIO_NET_CTRL_MQ_VQ_PAIRS_SET) {
> +		uint16_t queues;
> +
> +		queues = *(uint16_t *)(uintptr_t)
> +				vring->desc_packed[idx_data].addr;
> +		status = virtio_user_handle_mq(dev, queues);
> +	}
> +
> +	/* Update status */
> +	*(virtio_net_ctrl_ack *)(uintptr_t)
> +		vring->desc_packed[idx_status].addr = status;
> +
> +	return n_descs;
> +}
> +
> +void
> +virtio_user_handle_cq_packed(struct virtio_user_dev *dev, uint16_t queue_idx,
> +			     struct virtqueue *vq)
> +{
> +	struct vring_packed *vring = &dev->packed_vrings[queue_idx];
> +	uint16_t id, n_descs;
> +	int16_t n;
> +
> +	while (desc_is_avail(&vring->desc_packed[vq->vq_used_cons_idx],
> +			     vq->avail_wrap_counter)) {
> +		id = vring->desc_packed[vq->vq_used_cons_idx].id;
> +
> +		n_descs = virtio_user_handle_ctrl_msg_pq(dev, vring, id);
> +
> +		vring->desc_packed[vq->vq_used_cons_idx].len = n_descs;
> +		vring->desc_packed[vq->vq_used_cons_idx].id =
> +			vq->vq_used_cons_idx;
Are the above assignments necessary? I don't think so.

> +		n = vq->vq_used_cons_idx + n_descs - 1;
> +		do {
> +			vring->desc_packed[vq->vq_used_cons_idx].flags |=
> +				VRING_DESC_F_AVAIL(vq->used_wrap_counter) |
> +				VRING_DESC_F_USED(vq->used_wrap_counter);
> +			if (vq->vq_used_cons_idx >= dev->queue_size) {
> +				vq->vq_used_cons_idx -= dev->queue_size;
> +				vq->used_wrap_counter ^= 1;
> +			}
> +		} while (++vq->vq_used_cons_idx <= n);

I think it still does not work.
In case of wrap, n will be greater than queue size.
But as vq->vq_used_cons_idx wraps, I guess there will be an endless
loop.

> +	}
> +}
> +
>   void
>   virtio_user_handle_cq(struct virtio_user_dev *dev, uint16_t queue_idx)
>   {
> diff --git a/drivers/net/virtio/virtio_user/virtio_user_dev.h b/drivers/net/virtio/virtio_user/virtio_user_dev.h
> index 672a8161a..8be8ca622 100644
> --- a/drivers/net/virtio/virtio_user/virtio_user_dev.h
> +++ b/drivers/net/virtio/virtio_user/virtio_user_dev.h
> @@ -39,7 +39,11 @@ struct virtio_user_dev {
>   	uint16_t	port_id;
>   	uint8_t		mac_addr[ETHER_ADDR_LEN];
>   	char		path[PATH_MAX];
> -	struct vring	vrings[VIRTIO_MAX_VIRTQUEUES];
> +	union {
> +		struct vring		vrings[VIRTIO_MAX_VIRTQUEUES];
> +		struct vring_packed	packed_vrings[VIRTIO_MAX_VIRTQUEUES];
> +	};
> +
>   	struct virtio_user_backend_ops *ops;
>   	pthread_mutex_t	mutex;
>   	bool		started;
> @@ -53,5 +57,7 @@ int virtio_user_dev_init(struct virtio_user_dev *dev, char *path, int queues,
>   			 int mrg_rxbuf, int in_order, int packed_vq);
>   void virtio_user_dev_uninit(struct virtio_user_dev *dev);
>   void virtio_user_handle_cq(struct virtio_user_dev *dev, uint16_t queue_idx);
> +void virtio_user_handle_cq_packed(struct virtio_user_dev *dev,
> +		uint16_t queue_idx, struct virtqueue *vq);
>   uint8_t virtio_user_handle_mq(struct virtio_user_dev *dev, uint16_t q_pairs);
>   #endif
> diff --git a/drivers/net/virtio/virtio_user_ethdev.c b/drivers/net/virtio/virtio_user_ethdev.c
> index 2df6eb695..efc375cd7 100644
> --- a/drivers/net/virtio/virtio_user_ethdev.c
> +++ b/drivers/net/virtio/virtio_user_ethdev.c
> @@ -271,10 +271,36 @@ virtio_user_get_queue_num(struct virtio_hw *hw, uint16_t queue_id __rte_unused)
>   	return dev->queue_size;
>   }
>   
> -static int
> -virtio_user_setup_queue(struct virtio_hw *hw, struct virtqueue *vq)
> +static void
> +virtio_user_setup_queue_packed(struct virtqueue *vq,
> +			       struct virtio_user_dev *dev)
> +
> +{
> +	uint16_t queue_idx = vq->vq_queue_index;
> +	uint64_t desc_addr;
> +	uint64_t avail_addr;
> +	uint64_t used_addr;
> +
> +	desc_addr = (uintptr_t)vq->vq_ring_virt_mem;
> +	avail_addr = desc_addr + vq->vq_nentries *
> +		sizeof(struct vring_packed_desc);
> +	used_addr = RTE_ALIGN_CEIL(avail_addr +
> +			   sizeof(struct vring_packed_desc_event),
> +			   VIRTIO_PCI_VRING_ALIGN);
> +	dev->packed_vrings[queue_idx].num = vq->vq_nentries;
> +	dev->packed_vrings[queue_idx].desc_packed =
> +		(void *)(uintptr_t)desc_addr;
> +	dev->packed_vrings[queue_idx].driver_event =
> +		(void *)(uintptr_t)avail_addr;
> +	dev->packed_vrings[queue_idx].device_event =
> +		(void *)(uintptr_t)used_addr;
> +	vq->avail_wrap_counter = true;
> +	vq->used_wrap_counter = true;
> +}
> +
> +static void
> +virtio_user_setup_queue_split(struct virtqueue *vq, struct virtio_user_dev *dev)
>   {
> -	struct virtio_user_dev *dev = virtio_user_get_dev(hw);
>   	uint16_t queue_idx = vq->vq_queue_index;
>   	uint64_t desc_addr, avail_addr, used_addr;
>   
> @@ -288,6 +314,17 @@ virtio_user_setup_queue(struct virtio_hw *hw, struct virtqueue *vq)
>   	dev->vrings[queue_idx].desc = (void *)(uintptr_t)desc_addr;
>   	dev->vrings[queue_idx].avail = (void *)(uintptr_t)avail_addr;
>   	dev->vrings[queue_idx].used = (void *)(uintptr_t)used_addr;
> +}
> +
> +static int
> +virtio_user_setup_queue(struct virtio_hw *hw, struct virtqueue *vq)
> +{
> +	struct virtio_user_dev *dev = virtio_user_get_dev(hw);
> +
> +	if (vtpci_packed_queue(hw))
> +		virtio_user_setup_queue_packed(vq, dev);
> +	else
> +		virtio_user_setup_queue_split(vq, dev);
>   
>   	return 0;
>   }
> @@ -317,7 +354,11 @@ virtio_user_notify_queue(struct virtio_hw *hw, struct virtqueue *vq)
>   	struct virtio_user_dev *dev = virtio_user_get_dev(hw);
>   
>   	if (hw->cvq && (hw->cvq->vq == vq)) {
> -		virtio_user_handle_cq(dev, vq->vq_queue_index);
> +		if (vtpci_packed_queue(vq->hw))
> +			virtio_user_handle_cq_packed(dev, vq->vq_queue_index,
> +						     vq);
> +		else
> +			virtio_user_handle_cq(dev, vq->vq_queue_index);
>   		return;
>   	}
>   
>