[dpdk-dev] [PATCH 08/21] vhost: iotlb: add pending miss request list and helpers

[Maxime Coquelin]

In order to be able to handle other ports or queues while waiting
for an IOTLB miss reply, a pending list is created so that waiter
can return and restart later on with sending again a miss request.

Signed-off-by: Maxime Coquelin <maxime.coquelin at redhat.com>
---
 lib/librte_vhost/iotlb.c | 88 ++++++++++++++++++++++++++++++++++++++++++++++--
 lib/librte_vhost/iotlb.h |  4 +++
 lib/librte_vhost/vhost.h |  1 +
 3 files changed, 91 insertions(+), 2 deletions(-)

diff --git a/lib/librte_vhost/iotlb.c b/lib/librte_vhost/iotlb.c
index 1b739dae5..d014bfe98 100644
--- a/lib/librte_vhost/iotlb.c
+++ b/lib/librte_vhost/iotlb.c
@@ -49,7 +49,86 @@ struct vhost_iotlb_entry {
 	uint8_t perm;
 };
 
-#define IOTLB_CACHE_SIZE 1024
+#define IOTLB_CACHE_SIZE 2048
+
+static void vhost_user_iotlb_pending_remove_all(struct vhost_virtqueue *vq)
+{
+	struct vhost_iotlb_entry *node, *temp_node;
+
+	rte_rwlock_write_lock(&vq->iotlb_lock);
+
+	TAILQ_FOREACH_SAFE(node, &vq->iotlb_pending_list, next, temp_node) {
+		TAILQ_REMOVE(&vq->iotlb_pending_list, node, next);
+		rte_mempool_put(vq->iotlb_pool, node);
+	}
+
+	rte_rwlock_write_unlock(&vq->iotlb_lock);
+}
+
+int vhost_user_iotlb_pending_miss(struct vhost_virtqueue *vq, uint64_t iova,
+				uint8_t perm)
+{
+	struct vhost_iotlb_entry *node;
+	int found = 0;
+
+	rte_rwlock_read_lock(&vq->iotlb_lock);
+
+	TAILQ_FOREACH(node, &vq->iotlb_pending_list, next) {
+		if ((node->iova == iova) && (node->perm == perm)) {
+			found = 1;
+			break;
+		}
+	}
+
+	rte_rwlock_read_unlock(&vq->iotlb_lock);
+
+	return found;
+}
+
+void vhost_user_iotlb_pending_insert(struct vhost_virtqueue *vq,
+				uint64_t iova, uint8_t perm)
+{
+	struct vhost_iotlb_entry *node;
+	int ret;
+
+	ret = rte_mempool_get(vq->iotlb_pool, (void **)&node);
+	if (ret) {
+		RTE_LOG(ERR, VHOST_CONFIG, "IOTLB pool empty, invalidate cache\n");
+		vhost_user_iotlb_pending_remove_all(vq);
+		ret = rte_mempool_get(vq->iotlb_pool, (void **)&node);
+		if (ret) {
+			RTE_LOG(ERR, VHOST_CONFIG, "IOTLB pool still empty, failure\n");
+			return;
+		}
+	}
+
+	node->iova = iova;
+	node->perm = perm;
+
+	rte_rwlock_write_lock(&vq->iotlb_lock);
+
+	TAILQ_INSERT_TAIL(&vq->iotlb_pending_list, node, next);
+
+	rte_rwlock_write_unlock(&vq->iotlb_lock);
+}
+
+static void vhost_user_iotlb_pending_remove(struct vhost_virtqueue *vq,
+				uint64_t iova, uint64_t size, uint8_t perm)
+{
+	struct vhost_iotlb_entry *node, *temp_node;
+
+	/* .iotlb_lock already locked by the caller */
+	TAILQ_FOREACH_SAFE(node, &vq->iotlb_pending_list, next, temp_node) {
+		if (node->iova < iova)
+			continue;
+		if (node->iova >= iova + size)
+			continue;
+		if ((node->perm & perm) != node->perm)
+			continue;
+		TAILQ_REMOVE(&vq->iotlb_pending_list, node, next);
+		rte_mempool_put(vq->iotlb_pool, node);
+	}
+}
 
 static void vhost_user_iotlb_cache_remove_all(struct vhost_virtqueue *vq)
 {
@@ -106,7 +185,10 @@ void vhost_user_iotlb_cache_insert(struct vhost_virtqueue *vq, uint64_t iova,
 	TAILQ_INSERT_TAIL(&vq->iotlb_list, new_node, next);
 
 unlock:
+	vhost_user_iotlb_pending_remove(vq, iova, size, perm);
+
 	rte_rwlock_write_unlock(&vq->iotlb_lock);
+
 }
 
 void vhost_user_iotlb_cache_remove(struct vhost_virtqueue *vq,
@@ -189,9 +271,10 @@ int vhost_user_iotlb_init(struct virtio_net *dev, int vq_index)
 	if (vq->iotlb_pool) {
 		/*
 		 * The cache has already been initialized,
-		 * just drop all entries
+		 * just drop all cached and pending entries.
 		 */
 		vhost_user_iotlb_cache_remove_all(vq);
+		vhost_user_iotlb_pending_remove_all(vq);
 		return 0;
 	}
 
@@ -204,6 +287,7 @@ int vhost_user_iotlb_init(struct virtio_net *dev, int vq_index)
 	rte_rwlock_init(&vq->iotlb_lock);
 
 	TAILQ_INIT(&vq->iotlb_list);
+	TAILQ_INIT(&vq->iotlb_pending_list);
 
 	snprintf(pool_name, sizeof(pool_name), "iotlb_cache_%d_%d",
 			dev->vid, vq_index);
diff --git a/lib/librte_vhost/iotlb.h b/lib/librte_vhost/iotlb.h
index 459820762..4be1f7e85 100644
--- a/lib/librte_vhost/iotlb.h
+++ b/lib/librte_vhost/iotlb.h
@@ -41,6 +41,10 @@ void vhost_user_iotlb_cache_remove(struct vhost_virtqueue *vq,
 					uint64_t iova, uint64_t size);
 uint64_t vhost_user_iotlb_cache_find(struct vhost_virtqueue *vq, uint64_t iova,
 					uint64_t *size, uint8_t perm);
+int vhost_user_iotlb_pending_miss(struct vhost_virtqueue *vq, uint64_t iova,
+						uint8_t perm);
+void vhost_user_iotlb_pending_insert(struct vhost_virtqueue *vq, uint64_t iova,
+						uint8_t perm);
 int vhost_user_iotlb_init(struct virtio_net *dev, int vq_index);
 
 #endif /* _VHOST_IOTLB_H_ */
diff --git a/lib/librte_vhost/vhost.h b/lib/librte_vhost/vhost.h
index 7816a92b5..a41bacea7 100644
--- a/lib/librte_vhost/vhost.h
+++ b/lib/librte_vhost/vhost.h
@@ -119,6 +119,7 @@ struct vhost_virtqueue {
 	rte_rwlock_t	iotlb_lock;
 	struct rte_mempool *iotlb_pool;
 	TAILQ_HEAD(, vhost_iotlb_entry) iotlb_list;
+	TAILQ_HEAD(, vhost_iotlb_entry) iotlb_pending_list;
 } __rte_cache_aligned;
 
 /* Old kernels have no such macros defined */
-- 
2.13.3