Re: [dpdk-dev] [PATCH v7 4/8] vhost: rxtx: use queue id instead of constant ring index

["Michael S. Tsirkin" <mst@redhat.com>]

On Wed, Oct 21, 2015 at 11:48:10AM +0800, Yuanhan Liu wrote:
> From: Changchun Ouyang <changchun.ouyang@intel.com>
> 
> Do not use VIRTIO_RXQ or VIRTIO_TXQ anymore; use the queue_id
> instead, which will be set to a proper value for a specific queue
> when we have multiple queue support enabled.
> 
> For now, queue_id is still set with VIRTIO_RXQ or VIRTIO_TXQ,
> so it should not break anything.
> 
> Signed-off-by: Changchun Ouyang <changchun.ouyang@intel.com>
> Signed-off-by: Yuanhan Liu <yuanhan.liu@linux.intel.com>
> Acked-by: Flavio Leitner <fbl@sysclose.org>

I tried to figure out how is queue_id set and I couldn't.
Please note that for virtio devices, guest is supposed to
control the placement of incoming packets in RX queues.


> ---
> 
> v7: commit title fix
> ---
>  lib/librte_vhost/vhost_rxtx.c | 46 ++++++++++++++++++++++++++++++-------------
>  1 file changed, 32 insertions(+), 14 deletions(-)
> 
> diff --git a/lib/librte_vhost/vhost_rxtx.c b/lib/librte_vhost/vhost_rxtx.c
> index 7026bfa..14e00ef 100644
> --- a/lib/librte_vhost/vhost_rxtx.c
> +++ b/lib/librte_vhost/vhost_rxtx.c
> @@ -42,6 +42,16 @@
>  
>  #define MAX_PKT_BURST 32
>  
> +static inline int __attribute__((always_inline))
> +is_valid_virt_queue_idx(uint32_t virtq_idx, int is_tx, uint32_t max_qp_idx)
> +{
> +	if ((is_tx ^ (virtq_idx & 0x1)) ||
> +	    (virtq_idx >= max_qp_idx * VIRTIO_QNUM))
> +		return 0;
> +
> +	return 1;
> +}
> +
>  /**
>   * This function adds buffers to the virtio devices RX virtqueue. Buffers can
>   * be received from the physical port or from another virtio device. A packet
> @@ -68,12 +78,14 @@ virtio_dev_rx(struct virtio_net *dev, uint16_t queue_id,
>  	uint8_t success = 0;
>  
>  	LOG_DEBUG(VHOST_DATA, "(%"PRIu64") virtio_dev_rx()\n", dev->device_fh);
> -	if (unlikely(queue_id != VIRTIO_RXQ)) {
> -		LOG_DEBUG(VHOST_DATA, "mq isn't supported in this version.\n");
> +	if (unlikely(!is_valid_virt_queue_idx(queue_id, 0, dev->virt_qp_nb))) {
> +		RTE_LOG(ERR, VHOST_DATA,
> +			"%s (%"PRIu64"): virtqueue idx:%d invalid.\n",
> +			__func__, dev->device_fh, queue_id);
>  		return 0;
>  	}
>  
> -	vq = dev->virtqueue[VIRTIO_RXQ];
> +	vq = dev->virtqueue[queue_id];
>  	count = (count > MAX_PKT_BURST) ? MAX_PKT_BURST : count;
>  
>  	/*
> @@ -235,8 +247,9 @@ virtio_dev_rx(struct virtio_net *dev, uint16_t queue_id,
>  }
>  
>  static inline uint32_t __attribute__((always_inline))
> -copy_from_mbuf_to_vring(struct virtio_net *dev, uint16_t res_base_idx,
> -	uint16_t res_end_idx, struct rte_mbuf *pkt)
> +copy_from_mbuf_to_vring(struct virtio_net *dev, uint32_t queue_id,
> +			uint16_t res_base_idx, uint16_t res_end_idx,
> +			struct rte_mbuf *pkt)
>  {
>  	uint32_t vec_idx = 0;
>  	uint32_t entry_success = 0;
> @@ -264,7 +277,7 @@ copy_from_mbuf_to_vring(struct virtio_net *dev, uint16_t res_base_idx,
>  	 * Convert from gpa to vva
>  	 * (guest physical addr -> vhost virtual addr)
>  	 */
> -	vq = dev->virtqueue[VIRTIO_RXQ];
> +	vq = dev->virtqueue[queue_id];
>  	vb_addr = gpa_to_vva(dev, vq->buf_vec[vec_idx].buf_addr);
>  	vb_hdr_addr = vb_addr;
>  
> @@ -464,11 +477,14 @@ virtio_dev_merge_rx(struct virtio_net *dev, uint16_t queue_id,
>  
>  	LOG_DEBUG(VHOST_DATA, "(%"PRIu64") virtio_dev_merge_rx()\n",
>  		dev->device_fh);
> -	if (unlikely(queue_id != VIRTIO_RXQ)) {
> -		LOG_DEBUG(VHOST_DATA, "mq isn't supported in this version.\n");
> +	if (unlikely(!is_valid_virt_queue_idx(queue_id, 0, dev->virt_qp_nb))) {
> +		RTE_LOG(ERR, VHOST_DATA,
> +			"%s (%"PRIu64"): virtqueue idx:%d invalid.\n",
> +			__func__, dev->device_fh, queue_id);
> +		return 0;
>  	}
>  
> -	vq = dev->virtqueue[VIRTIO_RXQ];
> +	vq = dev->virtqueue[queue_id];
>  	count = RTE_MIN((uint32_t)MAX_PKT_BURST, count);
>  
>  	if (count == 0)
> @@ -509,8 +525,8 @@ virtio_dev_merge_rx(struct virtio_net *dev, uint16_t queue_id,
>  							res_cur_idx);
>  		} while (success == 0);
>  
> -		entry_success = copy_from_mbuf_to_vring(dev, res_base_idx,
> -			res_cur_idx, pkts[pkt_idx]);
> +		entry_success = copy_from_mbuf_to_vring(dev, queue_id,
> +			res_base_idx, res_cur_idx, pkts[pkt_idx]);
>  
>  		rte_compiler_barrier();
>  
> @@ -562,12 +578,14 @@ rte_vhost_dequeue_burst(struct virtio_net *dev, uint16_t queue_id,
>  	uint16_t free_entries, entry_success = 0;
>  	uint16_t avail_idx;
>  
> -	if (unlikely(queue_id != VIRTIO_TXQ)) {
> -		LOG_DEBUG(VHOST_DATA, "mq isn't supported in this version.\n");
> +	if (unlikely(!is_valid_virt_queue_idx(queue_id, 1, dev->virt_qp_nb))) {
> +		RTE_LOG(ERR, VHOST_DATA,
> +			"%s (%"PRIu64"): virtqueue idx:%d invalid.\n",
> +			__func__, dev->device_fh, queue_id);
>  		return 0;
>  	}
>  
> -	vq = dev->virtqueue[VIRTIO_TXQ];
> +	vq = dev->virtqueue[queue_id];
>  	avail_idx =  *((volatile uint16_t *)&vq->avail->idx);
>  
>  	/* If there are no available buffers then return. */
> -- 
> 1.9.0