[dpdk-dev] [PATCH v2] vhost: avoid iotlb mempool allocation while IOMMU disabled

[Wan Junjie]

If vhost device's IOMMU feature is disabled, iotlb mempool allocation
is unnecessary.

Reported-by: Peng He <hepeng.0320 at bytedance.com>
Signed-off-by: Wan Junjie <wanjunjie at bytedance.com>
Reviewed-by: Zhihong Wang <wangzhihong.wzh at bytedance.com>
---
 lib/librte_vhost/vhost.c      | 4 ++--
 lib/librte_vhost/vhost_user.c | 6 +++++-
 2 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/lib/librte_vhost/vhost.c b/lib/librte_vhost/vhost.c
index b83cf639e..e5341ab98 100644
--- a/lib/librte_vhost/vhost.c
+++ b/lib/librte_vhost/vhost.c
@@ -352,7 +352,8 @@ free_vq(struct virtio_net *dev, struct vhost_virtqueue *vq)
 		vhost_free_async_mem(vq);
 	}
 	rte_free(vq->batch_copy_elems);
-	rte_mempool_free(vq->iotlb_pool);
+	if (vq->iotlb_pool)
+		rte_mempool_free(vq->iotlb_pool);
 	rte_free(vq);
 }
 
@@ -556,7 +557,6 @@ init_vring_queue(struct virtio_net *dev, uint32_t vring_idx)
 	vq->callfd = VIRTIO_UNINITIALIZED_EVENTFD;
 	vq->notif_enable = VIRTIO_UNINITIALIZED_NOTIF;
 
-	vhost_user_iotlb_init(dev, vring_idx);
 	/* Backends are set to -1 indicating an inactive device. */
 	vq->backend = -1;
 }
diff --git a/lib/librte_vhost/vhost_user.c b/lib/librte_vhost/vhost_user.c
index 45c8ac09d..81cbb9797 100644
--- a/lib/librte_vhost/vhost_user.c
+++ b/lib/librte_vhost/vhost_user.c
@@ -470,6 +470,10 @@ vhost_user_set_vring_num(struct virtio_net **pdev,
 		return RTE_VHOST_MSG_RESULT_ERR;
 	}
 
+	if (dev->features & (1ULL << VIRTIO_F_IOMMU_PLATFORM)) {
+		if (vhost_user_iotlb_init(dev, msg->payload.state.index))
+			return RTE_VHOST_MSG_RESULT_ERR;
+	}
 	return RTE_VHOST_MSG_RESULT_OK;
 }
 
@@ -575,7 +579,7 @@ numa_realloc(struct virtio_net *dev, int index)
 	dev->virtqueue[index] = vq;
 	vhost_devices[dev->vid] = dev;
 
-	if (old_vq != vq)
+	if (old_vq != vq && (dev->features & (1ULL << VIRTIO_F_IOMMU_PLATFORM)))
 		vhost_user_iotlb_init(dev, index);
 
 	return dev;
-- 
2.11.0