[PATCH v6 1/3] net/virtio: make control queue thread-safe

[Xiao Wang <xiao.w.wang@intel.com>]

The virtio_send_command function may be called from app's configuration
routine, but also from an interrupt handler called when live migration is
done on the backup side. So this patch makes control queue thread-safe
first.

Signed-off-by: Xiao Wang <xiao.w.wang@intel.com>
---
 drivers/net/virtio/virtio_ethdev.c | 7 ++++++-
 drivers/net/virtio/virtio_rxtx.c   | 1 +
 drivers/net/virtio/virtio_rxtx.h   | 1 +
 3 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/drivers/net/virtio/virtio_ethdev.c b/drivers/net/virtio/virtio_ethdev.c
index e0328f61d..ac739506e 100644
--- a/drivers/net/virtio/virtio_ethdev.c
+++ b/drivers/net/virtio/virtio_ethdev.c
@@ -177,6 +177,8 @@ virtio_send_command(struct virtnet_ctl *cvq, struct virtio_pmd_ctrl *ctrl,
 		PMD_INIT_LOG(ERR, "Control queue is not supported.");
 		return -1;
 	}
+
+	rte_spinlock_lock(&cvq->sl);
 	vq = cvq->vq;
 	head = vq->vq_desc_head_idx;
 
@@ -184,8 +186,10 @@ virtio_send_command(struct virtnet_ctl *cvq, struct virtio_pmd_ctrl *ctrl,
 		"vq->hw->cvq = %p vq = %p",
 		vq->vq_desc_head_idx, status, vq->hw->cvq, vq);
 
-	if ((vq->vq_free_cnt < ((uint32_t)pkt_num + 2)) || (pkt_num < 1))
+	if (vq->vq_free_cnt < pkt_num + 2 || pkt_num < 1) {
+		rte_spinlock_unlock(&cvq->sl);
 		return -1;
+	}
 
 	memcpy(cvq->virtio_net_hdr_mz->addr, ctrl,
 		sizeof(struct virtio_pmd_ctrl));
@@ -261,6 +265,7 @@ virtio_send_command(struct virtnet_ctl *cvq, struct virtio_pmd_ctrl *ctrl,
 
 	result = cvq->virtio_net_hdr_mz->addr;
 
+	rte_spinlock_unlock(&cvq->sl);
 	return result->status;
 }
 
diff --git a/drivers/net/virtio/virtio_rxtx.c b/drivers/net/virtio/virtio_rxtx.c
index 390c137c8..6a24fdecb 100644
--- a/drivers/net/virtio/virtio_rxtx.c
+++ b/drivers/net/virtio/virtio_rxtx.c
@@ -407,6 +407,7 @@ virtio_dev_cq_start(struct rte_eth_dev *dev)
 	struct virtio_hw *hw = dev->data->dev_private;
 
 	if (hw->cvq && hw->cvq->vq) {
+		rte_spinlock_init(&hw->cvq->sl);
 		VIRTQUEUE_DUMP((struct virtqueue *)hw->cvq->vq);
 	}
 }
diff --git a/drivers/net/virtio/virtio_rxtx.h b/drivers/net/virtio/virtio_rxtx.h
index 54f1e849b..71b5798b0 100644
--- a/drivers/net/virtio/virtio_rxtx.h
+++ b/drivers/net/virtio/virtio_rxtx.h
@@ -84,6 +84,7 @@ struct virtnet_ctl {
 	rte_iova_t virtio_net_hdr_mem;  /**< hdr for each xmit packet */
 	uint16_t port_id;               /**< Device port identifier. */
 	const struct rte_memzone *mz;   /**< mem zone to populate CTL ring. */
+	rte_spinlock_t sl;              /**< spinlock for control queue. */
 };
 
 int virtio_rxq_vec_setup(struct virtnet_rx *rxvq);
-- 
2.15.1