[dpdk-dev] [PATCH v4 5/5] vhost: add apis for live migration

[Zhihong Wang <zhihong.wang@intel.com>]

This patch adds APIs to enable live migration for non-builtin data paths.

At src side, last_avail/used_idx from the device need to be set into the
virtio_net structure, and the log_base and log_size from the virtio_net
structure need to be set into the device.

At dst side, last_avail/used_idx need to be read from the virtio_net
structure and set into the device.

Signed-off-by: Zhihong Wang <zhihong.wang@intel.com>
---
 lib/librte_vhost/rte_vhost.h           | 51 +++++++++++++++++++++++++++
 lib/librte_vhost/rte_vhost_version.map |  3 ++
 lib/librte_vhost/vhost.c               | 63 ++++++++++++++++++++++++++++++++++
 3 files changed, 117 insertions(+)

diff --git a/lib/librte_vhost/rte_vhost.h b/lib/librte_vhost/rte_vhost.h
index 3c3334d3e..ff98ebd59 100644
--- a/lib/librte_vhost/rte_vhost.h
+++ b/lib/librte_vhost/rte_vhost.h
@@ -516,6 +516,57 @@ int rte_vhost_vring_call(int vid, uint16_t vring_idx);
 uint32_t rte_vhost_rx_queue_count(int vid, uint16_t qid);
 
 /**
+ * Get log base and log size of the vhost device
+ *
+ * @param vid
+ *  vhost device ID
+ * @param log_base
+ *  vhost log base
+ * @param log_size
+ *  vhost log size
+ * @return
+ *  0 on success, -1 on failure
+ */
+int __rte_experimental
+rte_vhost_get_log_base(int vid, uint64_t *log_base, uint64_t *log_size);
+
+/**
+ * Get last_avail/used_idx of the vhost virtqueue
+ *
+ * @param vid
+ *  vhost device ID
+ * @param queue_id
+ *  vhost queue index
+ * @param last_avail_idx
+ *  vhost last_avail_idx to get
+ * @param last_used_idx
+ *  vhost last_used_idx to get
+ * @return
+ *  0 on success, -1 on failure
+ */
+int __rte_experimental
+rte_vhost_get_vring_base(int vid, uint16_t queue_id,
+		uint16_t *last_avail_idx, uint16_t *last_used_idx);
+
+/**
+ * Set last_avail/used_idx of the vhost virtqueue
+ *
+ * @param vid
+ *  vhost device ID
+ * @param queue_id
+ *  vhost queue index
+ * @param last_avail_idx
+ *  last_avail_idx to set
+ * @param last_used_idx
+ *  last_used_idx to set
+ * @return
+ *  0 on success, -1 on failure
+ */
+int __rte_experimental
+rte_vhost_set_vring_base(int vid, uint16_t queue_id,
+		uint16_t last_avail_idx, uint16_t last_used_idx);
+
+/**
  * Get vdpa device id for vhost device.
  *
  * @param vid
diff --git a/lib/librte_vhost/rte_vhost_version.map b/lib/librte_vhost/rte_vhost_version.map
index 812ccd72b..81479d433 100644
--- a/lib/librte_vhost/rte_vhost_version.map
+++ b/lib/librte_vhost/rte_vhost_version.map
@@ -69,4 +69,7 @@ EXPERIMENTAL {
 	rte_vhost_get_vdpa_did;
 	rte_vhost_driver_get_protocol_features;
 	rte_vhost_driver_get_queue_num;
+	rte_vhost_get_log_base;
+	rte_vhost_get_vring_base;
+	rte_vhost_set_vring_base;
 } DPDK_18.02;
diff --git a/lib/librte_vhost/vhost.c b/lib/librte_vhost/vhost.c
index 66b6b492f..b52f7dad4 100644
--- a/lib/librte_vhost/vhost.c
+++ b/lib/librte_vhost/vhost.c
@@ -642,3 +642,66 @@ int rte_vhost_get_vdpa_did(int vid)
 
 	return dev->did;
 }
+
+int rte_vhost_get_log_base(int vid, uint64_t *log_base,
+		uint64_t *log_size)
+{
+	struct virtio_net *dev = get_device(vid);
+
+	if (!dev)
+		return -1;
+
+	if (unlikely(!(dev->flags & VIRTIO_DEV_BUILTIN_VIRTIO_NET))) {
+		RTE_LOG(ERR, VHOST_DATA,
+			"(%d) %s: built-in vhost net backend is disabled.\n",
+			dev->vid, __func__);
+		return -1;
+	}
+
+	*log_base = dev->log_base;
+	*log_size = dev->log_size;
+
+	return 0;
+}
+
+int rte_vhost_get_vring_base(int vid, uint16_t queue_id,
+		uint16_t *last_avail_idx, uint16_t *last_used_idx)
+{
+	struct virtio_net *dev = get_device(vid);
+
+	if (!dev)
+		return -1;
+
+	if (unlikely(!(dev->flags & VIRTIO_DEV_BUILTIN_VIRTIO_NET))) {
+		RTE_LOG(ERR, VHOST_DATA,
+			"(%d) %s: built-in vhost net backend is disabled.\n",
+			dev->vid, __func__);
+		return -1;
+	}
+
+	*last_avail_idx = dev->virtqueue[queue_id]->last_avail_idx;
+	*last_used_idx = dev->virtqueue[queue_id]->last_used_idx;
+
+	return 0;
+}
+
+int rte_vhost_set_vring_base(int vid, uint16_t queue_id,
+		uint16_t last_avail_idx, uint16_t last_used_idx)
+{
+	struct virtio_net *dev = get_device(vid);
+
+	if (!dev)
+		return -1;
+
+	if (unlikely(!(dev->flags & VIRTIO_DEV_BUILTIN_VIRTIO_NET))) {
+		RTE_LOG(ERR, VHOST_DATA,
+			"(%d) %s: built-in vhost net backend is disabled.\n",
+			dev->vid, __func__);
+		return -1;
+	}
+
+	dev->virtqueue[queue_id]->last_avail_idx = last_avail_idx;
+	dev->virtqueue[queue_id]->last_used_idx = last_used_idx;
+
+	return 0;
+}
-- 
2.13.6