vhost: support host notifier queue configuration

As an arrangement to per queue operations in the vDPA device it is
needed to change the next experimental API:

The API ``rte_vhost_host_notifier_ctrl`` was changed to be per queue
instead of per device.

A `qid` parameter was added to the API arguments list.

Setting the parameter to the value RTE_VHOST_QUEUE_ALL configures the
host notifier to all the device queues as done before this patch.

Signed-off-by: Matan Azrad <matan@mellanox.com>
Reviewed-by: Maxime Coquelin <maxime.coquelin@redhat.com>

doc/guides/rel_notes/release_20_08.rst

@@ -140,6 +140,9 @@ API Changes
 
 * ``rte_page_sizes`` enumeration is replaced with ``RTE_PGSIZE_xxx`` defines.
 
+* vhost: The API of ``rte_vhost_host_notifier_ctrl`` was changed to be per
+  queue and not per device, a qid parameter was added to the arguments list.
+
 
 ABI Changes
 -----------

drivers/vdpa/ifc/ifcvf_vdpa.c

@@ -840,7 +840,7 @@ ifcvf_sw_fallback_switchover(struct ifcvf_internal *internal)
 	vdpa_ifcvf_stop(internal);
 	vdpa_disable_vfio_intr(internal);
 
-	ret = rte_vhost_host_notifier_ctrl(vid, false);
+	ret = rte_vhost_host_notifier_ctrl(vid, RTE_VHOST_QUEUE_ALL, false);
 	if (ret && ret != -ENOTSUP)
 		goto error;
 
@@ -859,7 +859,7 @@ ifcvf_sw_fallback_switchover(struct ifcvf_internal *internal)
 	if (ret)
 		goto stop_vf;
 
-	rte_vhost_host_notifier_ctrl(vid, true);
+	rte_vhost_host_notifier_ctrl(vid, RTE_VHOST_QUEUE_ALL, true);
 
 	internal->sw_fallback_running = true;
 
@@ -894,7 +894,7 @@ ifcvf_dev_config(int vid)
 	rte_atomic32_set(&internal->dev_attached, 1);
 	update_datapath(internal);
 
-	if (rte_vhost_host_notifier_ctrl(vid, true) != 0)
+	if (rte_vhost_host_notifier_ctrl(vid, RTE_VHOST_QUEUE_ALL, true) != 0)
 		DRV_LOG(NOTICE, "vDPA (%s): software relay is used.",
 				vdev->device->name);
 

drivers/vdpa/mlx5/mlx5_vdpa.c

@@ -151,7 +151,8 @@ mlx5_vdpa_direct_db_prepare(struct mlx5_vdpa_priv *priv)
 	int ret;
 
 	if (priv->direct_notifier) {
-		ret = rte_vhost_host_notifier_ctrl(priv->vid, false);
+		ret = rte_vhost_host_notifier_ctrl(priv->vid,
+						   RTE_VHOST_QUEUE_ALL, false);
 		if (ret != 0) {
 			DRV_LOG(INFO, "Direct HW notifier FD cannot be "
 				"destroyed for device %d: %d.", priv->vid, ret);
@@ -159,7 +160,8 @@ mlx5_vdpa_direct_db_prepare(struct mlx5_vdpa_priv *priv)
 		}
 		priv->direct_notifier = 0;
 	}
-	ret = rte_vhost_host_notifier_ctrl(priv->vid, true);
+	ret = rte_vhost_host_notifier_ctrl(priv->vid, RTE_VHOST_QUEUE_ALL,
+					   true);
 	if (ret != 0)
 		DRV_LOG(INFO, "Direct HW notifier FD cannot be configured for"
 			" device %d: %d.", priv->vid, ret);

lib/librte_vhost/rte_vdpa_dev.h

@@ -9,6 +9,8 @@
 
 #include "rte_vhost.h"
 
+#define RTE_VHOST_QUEUE_ALL UINT16_MAX
+
 /**
  * vdpa device operations
  */
@@ -116,12 +118,14 @@ rte_vdpa_unregister_device(struct rte_vdpa_device *dev);
  *  vhost device id
  * @param enable
  *  true for host notifier map, false for host notifier unmap
+ * @param qid
+ *  vhost queue id, RTE_VHOST_QUEUE_ALL to configure all the device queues
  * @return
  *  0 on success, -1 on failure
  */
 __rte_experimental
 int
-rte_vhost_host_notifier_ctrl(int vid, bool enable);
+rte_vhost_host_notifier_ctrl(int vid, uint16_t qid, bool enable);
 
 /**
  * @warning

lib/librte_vhost/vhost_user.c

@@ -2943,13 +2943,13 @@ static int vhost_user_slave_set_vring_host_notifier(struct virtio_net *dev,
 	return process_slave_message_reply(dev, &msg);
 }
 
-int rte_vhost_host_notifier_ctrl(int vid, bool enable)
+int rte_vhost_host_notifier_ctrl(int vid, uint16_t qid, bool enable)
 {
 	struct virtio_net *dev;
 	struct rte_vdpa_device *vdpa_dev;
 	int vfio_device_fd, ret = 0;
 	uint64_t offset, size;
-	unsigned int i;
+	unsigned int i, q_start, q_last;
 
 	dev = get_device(vid);
 	if (!dev)
@@ -2969,6 +2969,16 @@ int rte_vhost_host_notifier_ctrl(int vid, bool enable)
 			(1ULL << VHOST_USER_PROTOCOL_F_HOST_NOTIFIER)))
 		return -ENOTSUP;
 
+	if (qid == RTE_VHOST_QUEUE_ALL) {
+		q_start = 0;
+		q_last = dev->nr_vring - 1;
+	} else {
+		if (qid >= dev->nr_vring)
+			return -EINVAL;
+		q_start = qid;
+		q_last = qid;
+	}
+
 	RTE_FUNC_PTR_OR_ERR_RET(vdpa_dev->ops->get_vfio_device_fd, -ENOTSUP);
 	RTE_FUNC_PTR_OR_ERR_RET(vdpa_dev->ops->get_notify_area, -ENOTSUP);
 
@@ -2977,7 +2987,7 @@ int rte_vhost_host_notifier_ctrl(int vid, bool enable)
 		return -ENOTSUP;
 
 	if (enable) {
-		for (i = 0; i < dev->nr_vring; i++) {
+		for (i = q_start; i <= q_last; i++) {
 			if (vdpa_dev->ops->get_notify_area(vid, i, &offset,
 					&size) < 0) {
 				ret = -ENOTSUP;
@@ -2992,7 +3002,7 @@ int rte_vhost_host_notifier_ctrl(int vid, bool enable)
 		}
 	} else {
 disable:
-		for (i = 0; i < dev->nr_vring; i++) {
+		for (i = q_start; i <= q_last; i++) {
 			vhost_user_slave_set_vring_host_notifier(dev, i, -1,
 					0, 0);
 		}