[PATCH 1/3] vhost: robustify virtqueue access lock asserts

[PATCH 1/3] vhost: robustify virtqueue access lock asserts

[David Marchand]

A simple comment in vhost_user_msg_handler() is not that robust.

Add a lock_all_qps property to message handlers so that their
implementation can add a build check and assert a vq is locked.

Signed-off-by: David Marchand <david.marchand@redhat.com>
---
 lib/vhost/vhost_user.c | 110 +++++++++++++++++++----------------------
 1 file changed, 51 insertions(+), 59 deletions(-)

diff --git a/lib/vhost/vhost_user.c b/lib/vhost/vhost_user.c
index 901a80bbaa..5bbdbd54d8 100644
--- a/lib/vhost/vhost_user.c
+++ b/lib/vhost/vhost_user.c
@@ -56,14 +56,24 @@
 #define INFLIGHT_ALIGNMENT	64
 #define INFLIGHT_VERSION	0x1
 
-typedef struct vhost_message_handler {
+typedef const struct vhost_message_handler {
 	const char *description;
 	int (*callback)(struct virtio_net **pdev, struct vhu_msg_context *ctx,
 		int main_fd);
 	bool accepts_fd;
+	bool lock_all_qps;
 } vhost_message_handler_t;
 static vhost_message_handler_t vhost_message_handlers[];
 
+/* vhost_user_msg_handler() locks all qps based on a handler's lock_all_qps.
+ * Later, a handler may need to ensure the vq has been locked (for example,
+ * when calling lock annotated helpers).
+ */
+#define VHOST_USER_ASSERT_LOCK(dev, vq, id) do { \
+	RTE_BUILD_BUG_ON(!vhost_message_handlers[id].lock_all_qps); \
+	vq_assert_lock(dev, vq); \
+} while (0)
+
 static int send_vhost_reply(struct virtio_net *dev, int sockfd, struct vhu_msg_context *ctx);
 static int read_vhost_message(struct virtio_net *dev, int sockfd, struct vhu_msg_context *ctx);
 
@@ -400,7 +410,7 @@ vhost_user_set_features(struct virtio_net **pdev,
 			cleanup_vq(vq, 1);
 			cleanup_vq_inflight(dev, vq);
 			/* vhost_user_lock_all_queue_pairs locked all qps */
-			vq_assert_lock(dev, vq);
+			VHOST_USER_ASSERT_LOCK(dev, vq, VHOST_USER_SET_FEATURES);
 			rte_rwlock_write_unlock(&vq->access_lock);
 			free_vq(dev, vq);
 		}
@@ -2224,7 +2234,7 @@ vhost_user_set_vring_enable(struct virtio_net **pdev,
 	vq = dev->virtqueue[index];
 	if (!(dev->flags & VIRTIO_DEV_VDPA_CONFIGURED)) {
 		/* vhost_user_lock_all_queue_pairs locked all qps */
-		vq_assert_lock(dev, vq);
+		VHOST_USER_ASSERT_LOCK(dev, vq, VHOST_USER_SET_VRING_ENABLE);
 		if (enable && vq->async && vq->async->pkts_inflight_n) {
 			VHOST_LOG_CONFIG(dev->ifname, ERR,
 				"failed to enable vring. Inflight packets must be completed first\n");
@@ -2829,41 +2839,43 @@ vhost_user_set_status(struct virtio_net **pdev,
 }
 
 #define VHOST_MESSAGE_HANDLERS \
-VHOST_MESSAGE_HANDLER(VHOST_USER_NONE, NULL, false) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_GET_FEATURES, vhost_user_get_features, false) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_SET_FEATURES, vhost_user_set_features, false) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_SET_OWNER, vhost_user_set_owner, false) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_RESET_OWNER, vhost_user_reset_owner, false) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_SET_MEM_TABLE, vhost_user_set_mem_table, true) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_SET_LOG_BASE, vhost_user_set_log_base, true) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_SET_LOG_FD, vhost_user_set_log_fd, true) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_SET_VRING_NUM, vhost_user_set_vring_num, false) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_SET_VRING_ADDR, vhost_user_set_vring_addr, false) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_SET_VRING_BASE, vhost_user_set_vring_base, false) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_GET_VRING_BASE, vhost_user_get_vring_base, false) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_SET_VRING_KICK, vhost_user_set_vring_kick, true) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_SET_VRING_CALL, vhost_user_set_vring_call, true) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_SET_VRING_ERR, vhost_user_set_vring_err, true) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_GET_PROTOCOL_FEATURES, vhost_user_get_protocol_features, false) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_SET_PROTOCOL_FEATURES, vhost_user_set_protocol_features, false) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_GET_QUEUE_NUM, vhost_user_get_queue_num, false) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_SET_VRING_ENABLE, vhost_user_set_vring_enable, false) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_SEND_RARP, vhost_user_send_rarp, false) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_NET_SET_MTU, vhost_user_net_set_mtu, false) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_SET_BACKEND_REQ_FD, vhost_user_set_req_fd, true) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_IOTLB_MSG, vhost_user_iotlb_msg, false) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_GET_CONFIG, vhost_user_get_config, false) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_SET_CONFIG, vhost_user_set_config, false) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_POSTCOPY_ADVISE, vhost_user_set_postcopy_advise, false) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_POSTCOPY_LISTEN, vhost_user_set_postcopy_listen, false) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_POSTCOPY_END, vhost_user_postcopy_end, false) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_GET_INFLIGHT_FD, vhost_user_get_inflight_fd, false) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_SET_INFLIGHT_FD, vhost_user_set_inflight_fd, true) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_SET_STATUS, vhost_user_set_status, false) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_GET_STATUS, vhost_user_get_status, false)
-
-#define VHOST_MESSAGE_HANDLER(id, handler, accepts_fd) \
-	[id] = { #id, handler, accepts_fd },
+VHOST_MESSAGE_HANDLER(VHOST_USER_NONE, NULL, false, false) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_GET_FEATURES, vhost_user_get_features, false, false) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_SET_FEATURES, vhost_user_set_features, false, true) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_SET_OWNER, vhost_user_set_owner, false, true) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_RESET_OWNER, vhost_user_reset_owner, false, false) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_SET_MEM_TABLE, vhost_user_set_mem_table, true, true) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_SET_LOG_BASE, vhost_user_set_log_base, true, true) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_SET_LOG_FD, vhost_user_set_log_fd, true, true) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_SET_VRING_NUM, vhost_user_set_vring_num, false, true) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_SET_VRING_ADDR, vhost_user_set_vring_addr, false, true) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_SET_VRING_BASE, vhost_user_set_vring_base, false, true) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_GET_VRING_BASE, vhost_user_get_vring_base, false, false) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_SET_VRING_KICK, vhost_user_set_vring_kick, true, true) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_SET_VRING_CALL, vhost_user_set_vring_call, true, true) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_SET_VRING_ERR, vhost_user_set_vring_err, true, true) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_GET_PROTOCOL_FEATURES, vhost_user_get_protocol_features, \
+	false, false) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_SET_PROTOCOL_FEATURES, vhost_user_set_protocol_features, \
+	false, true) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_GET_QUEUE_NUM, vhost_user_get_queue_num, false, false) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_SET_VRING_ENABLE, vhost_user_set_vring_enable, false, true) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_SEND_RARP, vhost_user_send_rarp, false, true) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_NET_SET_MTU, vhost_user_net_set_mtu, false, true) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_SET_BACKEND_REQ_FD, vhost_user_set_req_fd, true, true) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_IOTLB_MSG, vhost_user_iotlb_msg, false, false) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_GET_CONFIG, vhost_user_get_config, false, false) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_SET_CONFIG, vhost_user_set_config, false, false) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_POSTCOPY_ADVISE, vhost_user_set_postcopy_advise, false, false) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_POSTCOPY_LISTEN, vhost_user_set_postcopy_listen, false, false) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_POSTCOPY_END, vhost_user_postcopy_end, false, false) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_GET_INFLIGHT_FD, vhost_user_get_inflight_fd, false, false) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_SET_INFLIGHT_FD, vhost_user_set_inflight_fd, true, false) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_SET_STATUS, vhost_user_set_status, false, false) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_GET_STATUS, vhost_user_get_status, false, false)
+
+#define VHOST_MESSAGE_HANDLER(id, handler, accepts_fd, lock_all_qps) \
+	[id] = { #id, handler, accepts_fd, lock_all_qps },
 static vhost_message_handler_t vhost_message_handlers[] = {
 	VHOST_MESSAGE_HANDLERS
 };
@@ -3131,31 +3143,11 @@ vhost_user_msg_handler(int vid, int fd)
 	 * inactive, so it is safe. Otherwise taking the access_lock
 	 * would cause a dead lock.
 	 */
-	switch (request) {
-	case VHOST_USER_SET_FEATURES:
-	case VHOST_USER_SET_PROTOCOL_FEATURES:
-	case VHOST_USER_SET_OWNER:
-	case VHOST_USER_SET_MEM_TABLE:
-	case VHOST_USER_SET_LOG_BASE:
-	case VHOST_USER_SET_LOG_FD:
-	case VHOST_USER_SET_VRING_NUM:
-	case VHOST_USER_SET_VRING_ADDR:
-	case VHOST_USER_SET_VRING_BASE:
-	case VHOST_USER_SET_VRING_KICK:
-	case VHOST_USER_SET_VRING_CALL:
-	case VHOST_USER_SET_VRING_ERR:
-	case VHOST_USER_SET_VRING_ENABLE:
-	case VHOST_USER_SEND_RARP:
-	case VHOST_USER_NET_SET_MTU:
-	case VHOST_USER_SET_BACKEND_REQ_FD:
+	if (msg_handler->lock_all_qps) {
 		if (!(dev->flags & VIRTIO_DEV_VDPA_CONFIGURED)) {
 			vhost_user_lock_all_queue_pairs(dev);
 			unlock_required = 1;
 		}
-		break;
-	default:
-		break;
-
 	}
 
 	handled = false;
-- 
2.41.0

[PATCH 2/3] vhost: fix virtqueue access lock in datapath

[David Marchand]

Now that a r/w lock is used, the access_ok field should only be updated
under a write lock.

Since the datapath code only takes a read lock on the virtqueue to check
access_ok, this lock must be released and a write lock taken before
calling vring_translate().

Fixes: 03f77d66d966 ("vhost: change virtqueue access lock to a read/write one")
Cc: stable@dpdk.org

Signed-off-by: David Marchand <david.marchand@redhat.com>
---
 lib/vhost/virtio_net.c | 60 +++++++++++++++++++++++++++++++-----------
 1 file changed, 44 insertions(+), 16 deletions(-)

diff --git a/lib/vhost/virtio_net.c b/lib/vhost/virtio_net.c
index 759a78e3e3..4116f79d4f 100644
--- a/lib/vhost/virtio_net.c
+++ b/lib/vhost/virtio_net.c
@@ -1694,6 +1694,17 @@ virtio_dev_rx_packed(struct virtio_net *dev,
 	return pkt_idx;
 }
 
+static void
+virtio_dev_vring_translate(struct virtio_net *dev, struct vhost_virtqueue *vq)
+{
+	rte_rwlock_write_lock(&vq->access_lock);
+	vhost_user_iotlb_rd_lock(vq);
+	if (!vq->access_ok)
+		vring_translate(dev, vq);
+	vhost_user_iotlb_rd_unlock(vq);
+	rte_rwlock_write_unlock(&vq->access_lock);
+}
+
 static __rte_always_inline uint32_t
 virtio_dev_rx(struct virtio_net *dev, struct vhost_virtqueue *vq,
 	struct rte_mbuf **pkts, uint32_t count)
@@ -1708,9 +1719,13 @@ virtio_dev_rx(struct virtio_net *dev, struct vhost_virtqueue *vq,
 
 	vhost_user_iotlb_rd_lock(vq);
 
-	if (unlikely(!vq->access_ok))
-		if (unlikely(vring_translate(dev, vq) < 0))
-			goto out;
+	if (unlikely(!vq->access_ok)) {
+		vhost_user_iotlb_rd_unlock(vq);
+		rte_rwlock_read_unlock(&vq->access_lock);
+
+		virtio_dev_vring_translate(dev, vq);
+		goto out_no_unlock;
+	}
 
 	count = RTE_MIN((uint32_t)MAX_PKT_BURST, count);
 	if (count == 0)
@@ -1729,6 +1744,7 @@ virtio_dev_rx(struct virtio_net *dev, struct vhost_virtqueue *vq,
 out_access_unlock:
 	rte_rwlock_read_unlock(&vq->access_lock);
 
+out_no_unlock:
 	return nb_tx;
 }
 
@@ -2523,9 +2539,13 @@ virtio_dev_rx_async_submit(struct virtio_net *dev, struct vhost_virtqueue *vq,
 
 	vhost_user_iotlb_rd_lock(vq);
 
-	if (unlikely(!vq->access_ok))
-		if (unlikely(vring_translate(dev, vq) < 0))
-			goto out;
+	if (unlikely(!vq->access_ok)) {
+		vhost_user_iotlb_rd_unlock(vq);
+		rte_rwlock_read_unlock(&vq->access_lock);
+
+		virtio_dev_vring_translate(dev, vq);
+		goto out_no_unlock;
+	}
 
 	count = RTE_MIN((uint32_t)MAX_PKT_BURST, count);
 	if (count == 0)
@@ -2546,6 +2566,7 @@ virtio_dev_rx_async_submit(struct virtio_net *dev, struct vhost_virtqueue *vq,
 out_access_unlock:
 	rte_rwlock_write_unlock(&vq->access_lock);
 
+out_no_unlock:
 	return nb_tx;
 }
 
@@ -3576,11 +3597,13 @@ rte_vhost_dequeue_burst(int vid, uint16_t queue_id,
 
 	vhost_user_iotlb_rd_lock(vq);
 
-	if (unlikely(!vq->access_ok))
-		if (unlikely(vring_translate(dev, vq) < 0)) {
-			count = 0;
-			goto out;
-		}
+	if (unlikely(!vq->access_ok)) {
+		vhost_user_iotlb_rd_unlock(vq);
+		rte_rwlock_read_unlock(&vq->access_lock);
+
+		virtio_dev_vring_translate(dev, vq);
+		goto out_no_unlock;
+	}
 
 	/*
 	 * Construct a RARP broadcast packet, and inject it to the "pkts"
@@ -3641,6 +3664,7 @@ rte_vhost_dequeue_burst(int vid, uint16_t queue_id,
 	if (unlikely(rarp_mbuf != NULL))
 		count += 1;
 
+out_no_unlock:
 	return count;
 }
 
@@ -4190,11 +4214,14 @@ rte_vhost_async_try_dequeue_burst(int vid, uint16_t queue_id,
 
 	vhost_user_iotlb_rd_lock(vq);
 
-	if (unlikely(vq->access_ok == 0))
-		if (unlikely(vring_translate(dev, vq) < 0)) {
-			count = 0;
-			goto out;
-		}
+	if (unlikely(vq->access_ok == 0)) {
+		vhost_user_iotlb_rd_unlock(vq);
+		rte_rwlock_read_unlock(&vq->access_lock);
+
+		virtio_dev_vring_translate(dev, vq);
+		count = 0;
+		goto out_no_unlock;
+	}
 
 	/*
 	 * Construct a RARP broadcast packet, and inject it to the "pkts"
@@ -4260,5 +4287,6 @@ rte_vhost_async_try_dequeue_burst(int vid, uint16_t queue_id,
 	if (unlikely(rarp_mbuf != NULL))
 		count += 1;
 
+out_no_unlock:
 	return count;
 }
-- 
2.41.0

Re: [PATCH 2/3] vhost: fix virtqueue access lock in datapath

[Eelco Chaudron]

On 23 Oct 2023, at 11:55, David Marchand wrote:

> Now that a r/w lock is used, the access_ok field should only be updated
> under a write lock.
>
> Since the datapath code only takes a read lock on the virtqueue to check
> access_ok, this lock must be released and a write lock taken before
> calling vring_translate().
>
> Fixes: 03f77d66d966 ("vhost: change virtqueue access lock to a read/write one")
> Cc: stable@dpdk.org
>
> Signed-off-by: David Marchand <david.marchand@redhat.com>

Only one question, but whatever the outcome is the change looks good to me.

Acked-by: Eelco Chaudron <echaudro@redhat.com>

> ---
>  lib/vhost/virtio_net.c | 60 +++++++++++++++++++++++++++++++-----------
>  1 file changed, 44 insertions(+), 16 deletions(-)
>
> diff --git a/lib/vhost/virtio_net.c b/lib/vhost/virtio_net.c
> index 759a78e3e3..4116f79d4f 100644
> --- a/lib/vhost/virtio_net.c
> +++ b/lib/vhost/virtio_net.c
> @@ -1694,6 +1694,17 @@ virtio_dev_rx_packed(struct virtio_net *dev,
>  	return pkt_idx;
>  }
>
> +static void
> +virtio_dev_vring_translate(struct virtio_net *dev, struct vhost_virtqueue *vq)
> +{

Would it be an idea to annotate this function that it needs to be called with the “read locks” (and that it will free them) to avoid the duplicate:

+		vhost_user_iotlb_rd_unlock(vq);
+		rte_rwlock_read_unlock(&vq->access_lock);

> +	rte_rwlock_write_lock(&vq->access_lock);
> +	vhost_user_iotlb_rd_lock(vq);
> +	if (!vq->access_ok)
> +		vring_translate(dev, vq);
> +	vhost_user_iotlb_rd_unlock(vq);
> +	rte_rwlock_write_unlock(&vq->access_lock);
> +}
> +
>  static __rte_always_inline uint32_t
>  virtio_dev_rx(struct virtio_net *dev, struct vhost_virtqueue *vq,
>  	struct rte_mbuf **pkts, uint32_t count)
> @@ -1708,9 +1719,13 @@ virtio_dev_rx(struct virtio_net *dev, struct vhost_virtqueue *vq,
>
>  	vhost_user_iotlb_rd_lock(vq);
>
> -	if (unlikely(!vq->access_ok))
> -		if (unlikely(vring_translate(dev, vq) < 0))
> -			goto out;
> +	if (unlikely(!vq->access_ok)) {
> +		vhost_user_iotlb_rd_unlock(vq);
> +		rte_rwlock_read_unlock(&vq->access_lock);
> +
> +		virtio_dev_vring_translate(dev, vq);
> +		goto out_no_unlock;
> +	}
>
>  	count = RTE_MIN((uint32_t)MAX_PKT_BURST, count);
>  	if (count == 0)
> @@ -1729,6 +1744,7 @@ virtio_dev_rx(struct virtio_net *dev, struct vhost_virtqueue *vq,
>  out_access_unlock:
>  	rte_rwlock_read_unlock(&vq->access_lock);
>
> +out_no_unlock:
>  	return nb_tx;
>  }
>
> @@ -2523,9 +2539,13 @@ virtio_dev_rx_async_submit(struct virtio_net *dev, struct vhost_virtqueue *vq,
>
>  	vhost_user_iotlb_rd_lock(vq);
>
> -	if (unlikely(!vq->access_ok))
> -		if (unlikely(vring_translate(dev, vq) < 0))
> -			goto out;
> +	if (unlikely(!vq->access_ok)) {
> +		vhost_user_iotlb_rd_unlock(vq);
> +		rte_rwlock_read_unlock(&vq->access_lock);
> +
> +		virtio_dev_vring_translate(dev, vq);
> +		goto out_no_unlock;
> +	}
>
>  	count = RTE_MIN((uint32_t)MAX_PKT_BURST, count);
>  	if (count == 0)
> @@ -2546,6 +2566,7 @@ virtio_dev_rx_async_submit(struct virtio_net *dev, struct vhost_virtqueue *vq,
>  out_access_unlock:
>  	rte_rwlock_write_unlock(&vq->access_lock);
>
> +out_no_unlock:
>  	return nb_tx;
>  }
>
> @@ -3576,11 +3597,13 @@ rte_vhost_dequeue_burst(int vid, uint16_t queue_id,
>
>  	vhost_user_iotlb_rd_lock(vq);
>
> -	if (unlikely(!vq->access_ok))
> -		if (unlikely(vring_translate(dev, vq) < 0)) {
> -			count = 0;
> -			goto out;
> -		}
> +	if (unlikely(!vq->access_ok)) {
> +		vhost_user_iotlb_rd_unlock(vq);
> +		rte_rwlock_read_unlock(&vq->access_lock);
> +
> +		virtio_dev_vring_translate(dev, vq);
> +		goto out_no_unlock;
> +	}
>
>  	/*
>  	 * Construct a RARP broadcast packet, and inject it to the "pkts"
> @@ -3641,6 +3664,7 @@ rte_vhost_dequeue_burst(int vid, uint16_t queue_id,
>  	if (unlikely(rarp_mbuf != NULL))
>  		count += 1;
>
> +out_no_unlock:
>  	return count;
>  }
>
> @@ -4190,11 +4214,14 @@ rte_vhost_async_try_dequeue_burst(int vid, uint16_t queue_id,
>
>  	vhost_user_iotlb_rd_lock(vq);
>
> -	if (unlikely(vq->access_ok == 0))
> -		if (unlikely(vring_translate(dev, vq) < 0)) {
> -			count = 0;
> -			goto out;
> -		}
> +	if (unlikely(vq->access_ok == 0)) {
> +		vhost_user_iotlb_rd_unlock(vq);
> +		rte_rwlock_read_unlock(&vq->access_lock);
> +
> +		virtio_dev_vring_translate(dev, vq);
> +		count = 0;
> +		goto out_no_unlock;
> +	}
>
>  	/*
>  	 * Construct a RARP broadcast packet, and inject it to the "pkts"
> @@ -4260,5 +4287,6 @@ rte_vhost_async_try_dequeue_burst(int vid, uint16_t queue_id,
>  	if (unlikely(rarp_mbuf != NULL))
>  		count += 1;
>
> +out_no_unlock:
>  	return count;
>  }
> -- 
> 2.41.0

Re: [PATCH 2/3] vhost: fix virtqueue access lock in datapath

[David Marchand]

On Fri, Oct 27, 2023 at 11:05 AM Eelco Chaudron <echaudro@redhat.com> wrote:
> > diff --git a/lib/vhost/virtio_net.c b/lib/vhost/virtio_net.c
> > index 759a78e3e3..4116f79d4f 100644
> > --- a/lib/vhost/virtio_net.c
> > +++ b/lib/vhost/virtio_net.c
> > @@ -1694,6 +1694,17 @@ virtio_dev_rx_packed(struct virtio_net *dev,
> >       return pkt_idx;
> >  }
> >
> > +static void
> > +virtio_dev_vring_translate(struct virtio_net *dev, struct vhost_virtqueue *vq)
> > +{
>
> Would it be an idea to annotate this function that it needs to be called with the “read locks” (and that it will free them) to avoid the duplicate:
>
> +               vhost_user_iotlb_rd_unlock(vq);
> +               rte_rwlock_read_unlock(&vq->access_lock);

The "unlock" annotations do not express read/write concerns for locks.
So that would make the code less readable and potentially hide some issues.

I prefer to keep as is, with clear calls to rd_lock / rd_unlock in
those functions.

>
> > +     rte_rwlock_write_lock(&vq->access_lock);
> > +     vhost_user_iotlb_rd_lock(vq);
> > +     if (!vq->access_ok)
> > +             vring_translate(dev, vq);
> > +     vhost_user_iotlb_rd_unlock(vq);
> > +     rte_rwlock_write_unlock(&vq->access_lock);
> > +}
> > +

-- 
David Marchand

Re: [PATCH 2/3] vhost: fix virtqueue access lock in datapath

[Eelco Chaudron]

On 27 Oct 2023, at 11:22, David Marchand wrote:

> On Fri, Oct 27, 2023 at 11:05 AM Eelco Chaudron <echaudro@redhat.com> wrote:
>>> diff --git a/lib/vhost/virtio_net.c b/lib/vhost/virtio_net.c
>>> index 759a78e3e3..4116f79d4f 100644
>>> --- a/lib/vhost/virtio_net.c
>>> +++ b/lib/vhost/virtio_net.c
>>> @@ -1694,6 +1694,17 @@ virtio_dev_rx_packed(struct virtio_net *dev,
>>>       return pkt_idx;
>>>  }
>>>
>>> +static void
>>> +virtio_dev_vring_translate(struct virtio_net *dev, struct vhost_virtqueue *vq)
>>> +{
>>
>> Would it be an idea to annotate this function that it needs to be called with the “read locks” (and that it will free them) to avoid the duplicate:
>>
>> +               vhost_user_iotlb_rd_unlock(vq);
>> +               rte_rwlock_read_unlock(&vq->access_lock);
>
> The "unlock" annotations do not express read/write concerns for locks.
> So that would make the code less readable and potentially hide some issues.
>
> I prefer to keep as is, with clear calls to rd_lock / rd_unlock in
> those functions.

ACK, keeping this as is fine by me.

Acked-by: Eelco Chaudron <echaudro@redhat.com>

>>> +     rte_rwlock_write_lock(&vq->access_lock);
>>> +     vhost_user_iotlb_rd_lock(vq);
>>> +     if (!vq->access_ok)
>>> +             vring_translate(dev, vq);
>>> +     vhost_user_iotlb_rd_unlock(vq);
>>> +     rte_rwlock_write_unlock(&vq->access_lock);
>>> +}
>>> +
>
> -- 
> David Marchand

Re: [PATCH 2/3] vhost: fix virtqueue access lock in datapath

[Maxime Coquelin]

On 10/23/23 11:55, David Marchand wrote:
> Now that a r/w lock is used, the access_ok field should only be updated
> under a write lock.
> 
> Since the datapath code only takes a read lock on the virtqueue to check
> access_ok, this lock must be released and a write lock taken before
> calling vring_translate().
> 
> Fixes: 03f77d66d966 ("vhost: change virtqueue access lock to a read/write one")
> Cc: stable@dpdk.org
> 
> Signed-off-by: David Marchand <david.marchand@redhat.com>
> ---
>   lib/vhost/virtio_net.c | 60 +++++++++++++++++++++++++++++++-----------
>   1 file changed, 44 insertions(+), 16 deletions(-)
> 

Reviewed-by: Maxime Coquelin <maxime.coquelin@redhat.com>

[PATCH 3/3] vhost: annotate virtqueue access checks

[David Marchand]

Modifying vq->access_ok should be done with a write lock taken.
Annotate vring_translate() and vring_invalidate() and add missing locks.

Signed-off-by: David Marchand <david.marchand@redhat.com>
---
 lib/vhost/vduse.c      |  4 ++++
 lib/vhost/vhost.h      |  7 +++++--
 lib/vhost/vhost_user.c | 10 ++++++++++
 3 files changed, 19 insertions(+), 2 deletions(-)

diff --git a/lib/vhost/vduse.c b/lib/vhost/vduse.c
index 080b58f7de..e198eeef64 100644
--- a/lib/vhost/vduse.c
+++ b/lib/vhost/vduse.c
@@ -196,6 +196,7 @@ vduse_vring_setup(struct virtio_net *dev, unsigned int index)
 				vq->size * sizeof(struct batch_copy_elem),
 				RTE_CACHE_LINE_SIZE, 0);
 
+	rte_rwlock_write_lock(&vq->access_lock);
 	vhost_user_iotlb_rd_lock(vq);
 	if (vring_translate(dev, vq))
 		VHOST_LOG_CONFIG(dev->ifname, ERR, "Failed to translate vring %d addresses\n",
@@ -206,6 +207,7 @@ vduse_vring_setup(struct virtio_net *dev, unsigned int index)
 				"Failed to disable guest notifications on vring %d\n",
 				index);
 	vhost_user_iotlb_rd_unlock(vq);
+	rte_rwlock_write_unlock(&vq->access_lock);
 
 	vq_efd.index = index;
 	vq_efd.fd = vq->kickfd;
@@ -259,7 +261,9 @@ vduse_vring_cleanup(struct virtio_net *dev, unsigned int index)
 	close(vq->kickfd);
 	vq->kickfd = VIRTIO_UNINITIALIZED_EVENTFD;
 
+	rte_rwlock_write_lock(&vq->access_lock);
 	vring_invalidate(dev, vq);
+	rte_rwlock_write_unlock(&vq->access_lock);
 
 	rte_free(vq->batch_copy_elems);
 	vq->batch_copy_elems = NULL;
diff --git a/lib/vhost/vhost.h b/lib/vhost/vhost.h
index 5fc9035a1f..70d18bdfbf 100644
--- a/lib/vhost/vhost.h
+++ b/lib/vhost/vhost.h
@@ -295,7 +295,8 @@ struct vhost_virtqueue {
 #define VIRTIO_UNINITIALIZED_EVENTFD	(-2)
 
 	bool			enabled;
-	bool			access_ok;
+	/* Protected by vq->access_lock */
+	bool			access_ok __rte_guarded_var;
 	bool			ready;
 
 	rte_rwlock_t		access_lock;
@@ -874,11 +875,13 @@ void *vhost_alloc_copy_ind_table(struct virtio_net *dev,
 			uint64_t desc_addr, uint64_t desc_len)
 	__rte_shared_locks_required(&vq->iotlb_lock);
 int vring_translate(struct virtio_net *dev, struct vhost_virtqueue *vq)
+	__rte_exclusive_locks_required(&vq->access_lock)
 	__rte_shared_locks_required(&vq->iotlb_lock);
 uint64_t translate_log_addr(struct virtio_net *dev, struct vhost_virtqueue *vq,
 		uint64_t log_addr)
 	__rte_shared_locks_required(&vq->iotlb_lock);
-void vring_invalidate(struct virtio_net *dev, struct vhost_virtqueue *vq);
+void vring_invalidate(struct virtio_net *dev, struct vhost_virtqueue *vq)
+	__rte_exclusive_locks_required(&vq->access_lock);
 
 static __rte_always_inline uint64_t
 vhost_iova_to_vva(struct virtio_net *dev, struct vhost_virtqueue *vq,
diff --git a/lib/vhost/vhost_user.c b/lib/vhost/vhost_user.c
index 5bbdbd54d8..cbe2222ef3 100644
--- a/lib/vhost/vhost_user.c
+++ b/lib/vhost/vhost_user.c
@@ -797,6 +797,8 @@ translate_ring_addresses(struct virtio_net **pdev, struct vhost_virtqueue **pvq)
 	dev = *pdev;
 	vq = *pvq;
 
+	vq_assert_lock(dev, vq);
+
 	if (vq->ring_addrs.flags & (1 << VHOST_VRING_F_LOG)) {
 		vq->log_guest_addr =
 			log_addr_to_gpa(dev, vq);
@@ -934,6 +936,9 @@ vhost_user_set_vring_addr(struct virtio_net **pdev,
 	/* addr->index refers to the queue index. The txq 1, rxq is 0. */
 	vq = dev->virtqueue[ctx->msg.payload.addr.index];
 
+	/* vhost_user_lock_all_queue_pairs locked all qps */
+	VHOST_USER_ASSERT_LOCK(dev, vq, VHOST_USER_SET_VRING_ADDR);
+
 	access_ok = vq->access_ok;
 
 	/*
@@ -1446,6 +1451,9 @@ vhost_user_set_mem_table(struct virtio_net **pdev,
 			continue;
 
 		if (vq->desc || vq->avail || vq->used) {
+			/* vhost_user_lock_all_queue_pairs locked all qps */
+			VHOST_USER_ASSERT_LOCK(dev, vq, VHOST_USER_SET_MEM_TABLE);
+
 			/*
 			 * If the memory table got updated, the ring addresses
 			 * need to be translated again as virtual addresses have
@@ -2208,7 +2216,9 @@ vhost_user_get_vring_base(struct virtio_net **pdev,
 
 	vhost_user_iotlb_flush_all(dev);
 
+	rte_rwlock_write_lock(&vq->access_lock);
 	vring_invalidate(dev, vq);
+	rte_rwlock_write_unlock(&vq->access_lock);
 
 	return RTE_VHOST_MSG_RESULT_REPLY;
 }
-- 
2.41.0

Re: [PATCH 3/3] vhost: annotate virtqueue access checks

[Eelco Chaudron]

On 23 Oct 2023, at 11:55, David Marchand wrote:

> Modifying vq->access_ok should be done with a write lock taken.
> Annotate vring_translate() and vring_invalidate() and add missing locks.
>
> Signed-off-by: David Marchand <david.marchand@redhat.com>

The changes look good to me.

Acked-by: Eelco Chaudron <echaudro@redhat.com>

Re: [PATCH 1/3] vhost: robustify virtqueue access lock asserts

[Eelco Chaudron]

On 23 Oct 2023, at 11:55, David Marchand wrote:

> A simple comment in vhost_user_msg_handler() is not that robust.
>
> Add a lock_all_qps property to message handlers so that their
> implementation can add a build check and assert a vq is locked.
>
> Signed-off-by: David Marchand <david.marchand@redhat.com>

This change looks good to me.

Acked-by: Eelco Chaudron <echaudro@redhat.com>

Re: [PATCH 1/3] vhost: robustify virtqueue access lock asserts

[Maxime Coquelin]

s/robustify/enhance/ ?

On 10/23/23 11:55, David Marchand wrote:
> A simple comment in vhost_user_msg_handler() is not that robust.
> 
> Add a lock_all_qps property to message handlers so that their
> implementation can add a build check and assert a vq is locked.
> 
> Signed-off-by: David Marchand <david.marchand@redhat.com>
> ---
>   lib/vhost/vhost_user.c | 110 +++++++++++++++++++----------------------
>   1 file changed, 51 insertions(+), 59 deletions(-)
> 

I can reword the commit title while applying:

Reviewed-by: Maxime Coquelin <maxime.coquelin@redhat.com>

Thanks,
Maxime

[PATCH v2 1/5] vhost: fix virtqueue access check in datapath

[David Marchand]

Now that a r/w lock is used, the access_ok field should only be updated
under a write lock.

Since the datapath code only takes a read lock on the virtqueue to check
access_ok, this lock must be released and a write lock taken before
calling vring_translate().

Fixes: 03f77d66d966 ("vhost: change virtqueue access lock to a read/write one")
Cc: stable@dpdk.org

Signed-off-by: David Marchand <david.marchand@redhat.com>
Acked-by: Eelco Chaudron <echaudro@redhat.com>
Reviewed-by: Maxime Coquelin <maxime.coquelin@redhat.com>
---
 lib/vhost/virtio_net.c | 60 +++++++++++++++++++++++++++++++-----------
 1 file changed, 44 insertions(+), 16 deletions(-)

diff --git a/lib/vhost/virtio_net.c b/lib/vhost/virtio_net.c
index 8af20f1487..d00f4b03aa 100644
--- a/lib/vhost/virtio_net.c
+++ b/lib/vhost/virtio_net.c
@@ -1696,6 +1696,17 @@ virtio_dev_rx_packed(struct virtio_net *dev,
 	return pkt_idx;
 }
 
+static void
+virtio_dev_vring_translate(struct virtio_net *dev, struct vhost_virtqueue *vq)
+{
+	rte_rwlock_write_lock(&vq->access_lock);
+	vhost_user_iotlb_rd_lock(vq);
+	if (!vq->access_ok)
+		vring_translate(dev, vq);
+	vhost_user_iotlb_rd_unlock(vq);
+	rte_rwlock_write_unlock(&vq->access_lock);
+}
+
 static __rte_always_inline uint32_t
 virtio_dev_rx(struct virtio_net *dev, struct vhost_virtqueue *vq,
 	struct rte_mbuf **pkts, uint32_t count)
@@ -1710,9 +1721,13 @@ virtio_dev_rx(struct virtio_net *dev, struct vhost_virtqueue *vq,
 
 	vhost_user_iotlb_rd_lock(vq);
 
-	if (unlikely(!vq->access_ok))
-		if (unlikely(vring_translate(dev, vq) < 0))
-			goto out;
+	if (unlikely(!vq->access_ok)) {
+		vhost_user_iotlb_rd_unlock(vq);
+		rte_rwlock_read_unlock(&vq->access_lock);
+
+		virtio_dev_vring_translate(dev, vq);
+		goto out_no_unlock;
+	}
 
 	count = RTE_MIN((uint32_t)MAX_PKT_BURST, count);
 	if (count == 0)
@@ -1731,6 +1746,7 @@ virtio_dev_rx(struct virtio_net *dev, struct vhost_virtqueue *vq,
 out_access_unlock:
 	rte_rwlock_read_unlock(&vq->access_lock);
 
+out_no_unlock:
 	return nb_tx;
 }
 
@@ -2528,9 +2544,13 @@ virtio_dev_rx_async_submit(struct virtio_net *dev, struct vhost_virtqueue *vq,
 
 	vhost_user_iotlb_rd_lock(vq);
 
-	if (unlikely(!vq->access_ok))
-		if (unlikely(vring_translate(dev, vq) < 0))
-			goto out;
+	if (unlikely(!vq->access_ok)) {
+		vhost_user_iotlb_rd_unlock(vq);
+		rte_rwlock_read_unlock(&vq->access_lock);
+
+		virtio_dev_vring_translate(dev, vq);
+		goto out_no_unlock;
+	}
 
 	count = RTE_MIN((uint32_t)MAX_PKT_BURST, count);
 	if (count == 0)
@@ -2551,6 +2571,7 @@ virtio_dev_rx_async_submit(struct virtio_net *dev, struct vhost_virtqueue *vq,
 out_access_unlock:
 	rte_rwlock_write_unlock(&vq->access_lock);
 
+out_no_unlock:
 	return nb_tx;
 }
 
@@ -3581,11 +3602,13 @@ rte_vhost_dequeue_burst(int vid, uint16_t queue_id,
 
 	vhost_user_iotlb_rd_lock(vq);
 
-	if (unlikely(!vq->access_ok))
-		if (unlikely(vring_translate(dev, vq) < 0)) {
-			count = 0;
-			goto out;
-		}
+	if (unlikely(!vq->access_ok)) {
+		vhost_user_iotlb_rd_unlock(vq);
+		rte_rwlock_read_unlock(&vq->access_lock);
+
+		virtio_dev_vring_translate(dev, vq);
+		goto out_no_unlock;
+	}
 
 	/*
 	 * Construct a RARP broadcast packet, and inject it to the "pkts"
@@ -3646,6 +3669,7 @@ rte_vhost_dequeue_burst(int vid, uint16_t queue_id,
 	if (unlikely(rarp_mbuf != NULL))
 		count += 1;
 
+out_no_unlock:
 	return count;
 }
 
@@ -4196,11 +4220,14 @@ rte_vhost_async_try_dequeue_burst(int vid, uint16_t queue_id,
 
 	vhost_user_iotlb_rd_lock(vq);
 
-	if (unlikely(vq->access_ok == 0))
-		if (unlikely(vring_translate(dev, vq) < 0)) {
-			count = 0;
-			goto out;
-		}
+	if (unlikely(vq->access_ok == 0)) {
+		vhost_user_iotlb_rd_unlock(vq);
+		rte_rwlock_read_unlock(&vq->access_lock);
+
+		virtio_dev_vring_translate(dev, vq);
+		count = 0;
+		goto out_no_unlock;
+	}
 
 	/*
 	 * Construct a RARP broadcast packet, and inject it to the "pkts"
@@ -4266,5 +4293,6 @@ rte_vhost_async_try_dequeue_burst(int vid, uint16_t queue_id,
 	if (unlikely(rarp_mbuf != NULL))
 		count += 1;
 
+out_no_unlock:
 	return count;
 }
-- 
2.42.0

[PATCH v2 2/5] vhost: fix virtqueue access check in VDUSE setup

[David Marchand]

vring_translate and vring_invalidate change the vq access_ok field.
The access_ok field should only be updated under a (write) lock.

Fixes: a9120db8b98b ("vhost: add VDUSE device startup")
Fixes: ad67c65efda1 ("vhost: add VDUSE device stop")
Cc: stable@dpdk.org

Signed-off-by: David Marchand <david.marchand@redhat.com>
Acked-by: Eelco Chaudron <echaudro@redhat.com>
---
Changes since v1:
- moved fix out of patch 3,

---
 lib/vhost/vduse.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/lib/vhost/vduse.c b/lib/vhost/vduse.c
index 080b58f7de..e198eeef64 100644
--- a/lib/vhost/vduse.c
+++ b/lib/vhost/vduse.c
@@ -196,6 +196,7 @@ vduse_vring_setup(struct virtio_net *dev, unsigned int index)
 				vq->size * sizeof(struct batch_copy_elem),
 				RTE_CACHE_LINE_SIZE, 0);
 
+	rte_rwlock_write_lock(&vq->access_lock);
 	vhost_user_iotlb_rd_lock(vq);
 	if (vring_translate(dev, vq))
 		VHOST_LOG_CONFIG(dev->ifname, ERR, "Failed to translate vring %d addresses\n",
@@ -206,6 +207,7 @@ vduse_vring_setup(struct virtio_net *dev, unsigned int index)
 				"Failed to disable guest notifications on vring %d\n",
 				index);
 	vhost_user_iotlb_rd_unlock(vq);
+	rte_rwlock_write_unlock(&vq->access_lock);
 
 	vq_efd.index = index;
 	vq_efd.fd = vq->kickfd;
@@ -259,7 +261,9 @@ vduse_vring_cleanup(struct virtio_net *dev, unsigned int index)
 	close(vq->kickfd);
 	vq->kickfd = VIRTIO_UNINITIALIZED_EVENTFD;
 
+	rte_rwlock_write_lock(&vq->access_lock);
 	vring_invalidate(dev, vq);
+	rte_rwlock_write_unlock(&vq->access_lock);
 
 	rte_free(vq->batch_copy_elems);
 	vq->batch_copy_elems = NULL;
-- 
2.42.0

Re: [PATCH v2 2/5] vhost: fix virtqueue access check in VDUSE setup

[Maxime Coquelin]

On 12/5/23 10:45, David Marchand wrote:
> vring_translate and vring_invalidate change the vq access_ok field.
> The access_ok field should only be updated under a (write) lock.
> 
> Fixes: a9120db8b98b ("vhost: add VDUSE device startup")
> Fixes: ad67c65efda1 ("vhost: add VDUSE device stop")
> Cc: stable@dpdk.org
> 
> Signed-off-by: David Marchand <david.marchand@redhat.com>
> Acked-by: Eelco Chaudron <echaudro@redhat.com>
> ---
> Changes since v1:
> - moved fix out of patch 3,
> 
> ---
>   lib/vhost/vduse.c | 4 ++++
>   1 file changed, 4 insertions(+)
> 

Reviewed-by: Maxime Coquelin <maxime.coquelin@redhat.com>

Thanks,
Maxime

[PATCH v2 3/5] vhost: fix virtqueue access check in vhost-user setup

[David Marchand]

Calling vring_invalidate must be done with a (write) lock taken on the
virtqueue.

Fixes: 72d002b3ebda ("vhost: fix vring address handling during live migration")
Cc: stable@dpdk.org

Signed-off-by: David Marchand <david.marchand@redhat.com>
Acked-by: Eelco Chaudron <echaudro@redhat.com>
---
Changes since v1:
- moved fix out of patch 3,

---
 lib/vhost/vhost_user.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/lib/vhost/vhost_user.c b/lib/vhost/vhost_user.c
index e36312181a..a323ce5fbf 100644
--- a/lib/vhost/vhost_user.c
+++ b/lib/vhost/vhost_user.c
@@ -2198,7 +2198,9 @@ vhost_user_get_vring_base(struct virtio_net **pdev,
 
 	vhost_user_iotlb_flush_all(dev);
 
+	rte_rwlock_write_lock(&vq->access_lock);
 	vring_invalidate(dev, vq);
+	rte_rwlock_write_unlock(&vq->access_lock);
 
 	return RTE_VHOST_MSG_RESULT_REPLY;
 }
-- 
2.42.0

Re: [PATCH v2 3/5] vhost: fix virtqueue access check in vhost-user setup

[Maxime Coquelin]

On 12/5/23 10:45, David Marchand wrote:
> Calling vring_invalidate must be done with a (write) lock taken on the
> virtqueue.
> 
> Fixes: 72d002b3ebda ("vhost: fix vring address handling during live migration")
> Cc: stable@dpdk.org
> 
> Signed-off-by: David Marchand <david.marchand@redhat.com>
> Acked-by: Eelco Chaudron <echaudro@redhat.com>
> ---
> Changes since v1:
> - moved fix out of patch 3,
> 
> ---
>   lib/vhost/vhost_user.c | 2 ++
>   1 file changed, 2 insertions(+)

Reviewed-by: Maxime Coquelin <maxime.coquelin@redhat.com>

Thanks,
Maxime

[PATCH v2 4/5] vhost: annotate virtqueue access checks

[David Marchand]

Modifying vq->access_ok should be done with a write lock taken.
Annotate vring_translate() and vring_invalidate().

Signed-off-by: David Marchand <david.marchand@redhat.com>
Acked-by: Eelco Chaudron <echaudro@redhat.com>
---
Changes since v1:
- moved fixes in separate patches,

---
 lib/vhost/vhost.h      | 7 +++++--
 lib/vhost/vhost_user.c | 8 ++++++++
 2 files changed, 13 insertions(+), 2 deletions(-)

diff --git a/lib/vhost/vhost.h b/lib/vhost/vhost.h
index f8624fba3d..6767246656 100644
--- a/lib/vhost/vhost.h
+++ b/lib/vhost/vhost.h
@@ -295,7 +295,8 @@ struct vhost_virtqueue {
 #define VIRTIO_UNINITIALIZED_EVENTFD	(-2)
 
 	bool			enabled;
-	bool			access_ok;
+	/* Protected by vq->access_lock */
+	bool			access_ok __rte_guarded_var;
 	bool			ready;
 
 	rte_rwlock_t		access_lock;
@@ -875,11 +876,13 @@ void *vhost_alloc_copy_ind_table(struct virtio_net *dev,
 			uint64_t desc_addr, uint64_t desc_len)
 	__rte_shared_locks_required(&vq->iotlb_lock);
 int vring_translate(struct virtio_net *dev, struct vhost_virtqueue *vq)
+	__rte_exclusive_locks_required(&vq->access_lock)
 	__rte_shared_locks_required(&vq->iotlb_lock);
 uint64_t translate_log_addr(struct virtio_net *dev, struct vhost_virtqueue *vq,
 		uint64_t log_addr)
 	__rte_shared_locks_required(&vq->iotlb_lock);
-void vring_invalidate(struct virtio_net *dev, struct vhost_virtqueue *vq);
+void vring_invalidate(struct virtio_net *dev, struct vhost_virtqueue *vq)
+	__rte_exclusive_locks_required(&vq->access_lock);
 
 static __rte_always_inline uint64_t
 vhost_iova_to_vva(struct virtio_net *dev, struct vhost_virtqueue *vq,
diff --git a/lib/vhost/vhost_user.c b/lib/vhost/vhost_user.c
index a323ce5fbf..651ea5854b 100644
--- a/lib/vhost/vhost_user.c
+++ b/lib/vhost/vhost_user.c
@@ -787,6 +787,8 @@ translate_ring_addresses(struct virtio_net **pdev, struct vhost_virtqueue **pvq)
 	dev = *pdev;
 	vq = *pvq;
 
+	vq_assert_lock(dev, vq);
+
 	if (vq->ring_addrs.flags & (1 << VHOST_VRING_F_LOG)) {
 		vq->log_guest_addr =
 			log_addr_to_gpa(dev, vq);
@@ -924,6 +926,9 @@ vhost_user_set_vring_addr(struct virtio_net **pdev,
 	/* addr->index refers to the queue index. The txq 1, rxq is 0. */
 	vq = dev->virtqueue[ctx->msg.payload.addr.index];
 
+	/* vhost_user_lock_all_queue_pairs locked all qps */
+	vq_assert_lock(dev, vq);
+
 	access_ok = vq->access_ok;
 
 	/*
@@ -1436,6 +1441,9 @@ vhost_user_set_mem_table(struct virtio_net **pdev,
 			continue;
 
 		if (vq->desc || vq->avail || vq->used) {
+			/* vhost_user_lock_all_queue_pairs locked all qps */
+			vq_assert_lock(dev, vq);
+
 			/*
 			 * If the memory table got updated, the ring addresses
 			 * need to be translated again as virtual addresses have
-- 
2.42.0

Re: [PATCH v2 4/5] vhost: annotate virtqueue access checks

[Maxime Coquelin]

On 12/5/23 10:45, David Marchand wrote:
> Modifying vq->access_ok should be done with a write lock taken.
> Annotate vring_translate() and vring_invalidate().
> 
> Signed-off-by: David Marchand <david.marchand@redhat.com>
> Acked-by: Eelco Chaudron <echaudro@redhat.com>
> ---
> Changes since v1:
> - moved fixes in separate patches,
> 
> ---
>   lib/vhost/vhost.h      | 7 +++++--
>   lib/vhost/vhost_user.c | 8 ++++++++
>   2 files changed, 13 insertions(+), 2 deletions(-)
> 

Reviewed-by: Maxime Coquelin <maxime.coquelin@redhat.com>

Thanks,
Maxime

[PATCH v2 5/5] vhost: enhance virtqueue access lock asserts

[David Marchand]

A simple comment in vhost_user_msg_handler() is not that robust.

Add a lock_all_qps property to message handlers so that their
implementation can add a build check and assert a vq is locked.

Signed-off-by: David Marchand <david.marchand@redhat.com>
Acked-by: Eelco Chaudron <echaudro@redhat.com>
Reviewed-by: Maxime Coquelin <maxime.coquelin@redhat.com>
---
Changes since v1:
- moved this patch as the last of the series,

---
 lib/vhost/vhost_user.c | 114 +++++++++++++++++++----------------------
 1 file changed, 53 insertions(+), 61 deletions(-)

diff --git a/lib/vhost/vhost_user.c b/lib/vhost/vhost_user.c
index 651ea5854b..e8020ccfd3 100644
--- a/lib/vhost/vhost_user.c
+++ b/lib/vhost/vhost_user.c
@@ -56,14 +56,24 @@
 #define INFLIGHT_ALIGNMENT	64
 #define INFLIGHT_VERSION	0x1
 
-typedef struct vhost_message_handler {
+typedef const struct vhost_message_handler {
 	const char *description;
 	int (*callback)(struct virtio_net **pdev, struct vhu_msg_context *ctx,
 		int main_fd);
 	bool accepts_fd;
+	bool lock_all_qps;
 } vhost_message_handler_t;
 static vhost_message_handler_t vhost_message_handlers[];
 
+/* vhost_user_msg_handler() locks all qps based on a handler's lock_all_qps.
+ * Later, a handler may need to ensure the vq has been locked (for example,
+ * when calling lock annotated helpers).
+ */
+#define VHOST_USER_ASSERT_LOCK(dev, vq, id) do { \
+	RTE_BUILD_BUG_ON(!vhost_message_handlers[id].lock_all_qps); \
+	vq_assert_lock(dev, vq); \
+} while (0)
+
 static int send_vhost_reply(struct virtio_net *dev, int sockfd, struct vhu_msg_context *ctx);
 static int read_vhost_message(struct virtio_net *dev, int sockfd, struct vhu_msg_context *ctx);
 
@@ -400,7 +410,7 @@ vhost_user_set_features(struct virtio_net **pdev,
 			cleanup_vq(vq, 1);
 			cleanup_vq_inflight(dev, vq);
 			/* vhost_user_lock_all_queue_pairs locked all qps */
-			vq_assert_lock(dev, vq);
+			VHOST_USER_ASSERT_LOCK(dev, vq, VHOST_USER_SET_FEATURES);
 			rte_rwlock_write_unlock(&vq->access_lock);
 			free_vq(dev, vq);
 		}
@@ -927,7 +937,7 @@ vhost_user_set_vring_addr(struct virtio_net **pdev,
 	vq = dev->virtqueue[ctx->msg.payload.addr.index];
 
 	/* vhost_user_lock_all_queue_pairs locked all qps */
-	vq_assert_lock(dev, vq);
+	VHOST_USER_ASSERT_LOCK(dev, vq, VHOST_USER_SET_VRING_ADDR);
 
 	access_ok = vq->access_ok;
 
@@ -1442,7 +1452,7 @@ vhost_user_set_mem_table(struct virtio_net **pdev,
 
 		if (vq->desc || vq->avail || vq->used) {
 			/* vhost_user_lock_all_queue_pairs locked all qps */
-			vq_assert_lock(dev, vq);
+			VHOST_USER_ASSERT_LOCK(dev, vq, VHOST_USER_SET_MEM_TABLE);
 
 			/*
 			 * If the memory table got updated, the ring addresses
@@ -2234,7 +2244,7 @@ vhost_user_set_vring_enable(struct virtio_net **pdev,
 	vq = dev->virtqueue[index];
 	if (!(dev->flags & VIRTIO_DEV_VDPA_CONFIGURED)) {
 		/* vhost_user_lock_all_queue_pairs locked all qps */
-		vq_assert_lock(dev, vq);
+		VHOST_USER_ASSERT_LOCK(dev, vq, VHOST_USER_SET_VRING_ENABLE);
 		if (enable && vq->async && vq->async->pkts_inflight_n) {
 			VHOST_LOG_CONFIG(dev->ifname, ERR,
 				"failed to enable vring. Inflight packets must be completed first\n");
@@ -2839,41 +2849,43 @@ vhost_user_set_status(struct virtio_net **pdev,
 }
 
 #define VHOST_MESSAGE_HANDLERS \
-VHOST_MESSAGE_HANDLER(VHOST_USER_NONE, NULL, false) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_GET_FEATURES, vhost_user_get_features, false) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_SET_FEATURES, vhost_user_set_features, false) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_SET_OWNER, vhost_user_set_owner, false) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_RESET_OWNER, vhost_user_reset_owner, false) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_SET_MEM_TABLE, vhost_user_set_mem_table, true) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_SET_LOG_BASE, vhost_user_set_log_base, true) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_SET_LOG_FD, vhost_user_set_log_fd, true) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_SET_VRING_NUM, vhost_user_set_vring_num, false) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_SET_VRING_ADDR, vhost_user_set_vring_addr, false) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_SET_VRING_BASE, vhost_user_set_vring_base, false) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_GET_VRING_BASE, vhost_user_get_vring_base, false) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_SET_VRING_KICK, vhost_user_set_vring_kick, true) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_SET_VRING_CALL, vhost_user_set_vring_call, true) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_SET_VRING_ERR, vhost_user_set_vring_err, true) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_GET_PROTOCOL_FEATURES, vhost_user_get_protocol_features, false) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_SET_PROTOCOL_FEATURES, vhost_user_set_protocol_features, false) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_GET_QUEUE_NUM, vhost_user_get_queue_num, false) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_SET_VRING_ENABLE, vhost_user_set_vring_enable, false) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_SEND_RARP, vhost_user_send_rarp, false) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_NET_SET_MTU, vhost_user_net_set_mtu, false) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_SET_BACKEND_REQ_FD, vhost_user_set_req_fd, true) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_IOTLB_MSG, vhost_user_iotlb_msg, false) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_GET_CONFIG, vhost_user_get_config, false) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_SET_CONFIG, vhost_user_set_config, false) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_POSTCOPY_ADVISE, vhost_user_set_postcopy_advise, false) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_POSTCOPY_LISTEN, vhost_user_set_postcopy_listen, false) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_POSTCOPY_END, vhost_user_postcopy_end, false) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_GET_INFLIGHT_FD, vhost_user_get_inflight_fd, false) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_SET_INFLIGHT_FD, vhost_user_set_inflight_fd, true) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_SET_STATUS, vhost_user_set_status, false) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_GET_STATUS, vhost_user_get_status, false)
-
-#define VHOST_MESSAGE_HANDLER(id, handler, accepts_fd) \
-	[id] = { #id, handler, accepts_fd },
+VHOST_MESSAGE_HANDLER(VHOST_USER_NONE, NULL, false, false) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_GET_FEATURES, vhost_user_get_features, false, false) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_SET_FEATURES, vhost_user_set_features, false, true) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_SET_OWNER, vhost_user_set_owner, false, true) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_RESET_OWNER, vhost_user_reset_owner, false, false) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_SET_MEM_TABLE, vhost_user_set_mem_table, true, true) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_SET_LOG_BASE, vhost_user_set_log_base, true, true) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_SET_LOG_FD, vhost_user_set_log_fd, true, true) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_SET_VRING_NUM, vhost_user_set_vring_num, false, true) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_SET_VRING_ADDR, vhost_user_set_vring_addr, false, true) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_SET_VRING_BASE, vhost_user_set_vring_base, false, true) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_GET_VRING_BASE, vhost_user_get_vring_base, false, false) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_SET_VRING_KICK, vhost_user_set_vring_kick, true, true) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_SET_VRING_CALL, vhost_user_set_vring_call, true, true) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_SET_VRING_ERR, vhost_user_set_vring_err, true, true) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_GET_PROTOCOL_FEATURES, vhost_user_get_protocol_features, \
+	false, false) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_SET_PROTOCOL_FEATURES, vhost_user_set_protocol_features, \
+	false, true) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_GET_QUEUE_NUM, vhost_user_get_queue_num, false, false) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_SET_VRING_ENABLE, vhost_user_set_vring_enable, false, true) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_SEND_RARP, vhost_user_send_rarp, false, true) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_NET_SET_MTU, vhost_user_net_set_mtu, false, true) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_SET_BACKEND_REQ_FD, vhost_user_set_req_fd, true, true) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_IOTLB_MSG, vhost_user_iotlb_msg, false, false) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_GET_CONFIG, vhost_user_get_config, false, false) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_SET_CONFIG, vhost_user_set_config, false, false) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_POSTCOPY_ADVISE, vhost_user_set_postcopy_advise, false, false) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_POSTCOPY_LISTEN, vhost_user_set_postcopy_listen, false, false) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_POSTCOPY_END, vhost_user_postcopy_end, false, false) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_GET_INFLIGHT_FD, vhost_user_get_inflight_fd, false, false) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_SET_INFLIGHT_FD, vhost_user_set_inflight_fd, true, false) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_SET_STATUS, vhost_user_set_status, false, false) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_GET_STATUS, vhost_user_get_status, false, false)
+
+#define VHOST_MESSAGE_HANDLER(id, handler, accepts_fd, lock_all_qps) \
+	[id] = { #id, handler, accepts_fd, lock_all_qps },
 static vhost_message_handler_t vhost_message_handlers[] = {
 	VHOST_MESSAGE_HANDLERS
 };
@@ -3141,31 +3153,11 @@ vhost_user_msg_handler(int vid, int fd)
 	 * inactive, so it is safe. Otherwise taking the access_lock
 	 * would cause a dead lock.
 	 */
-	switch (request) {
-	case VHOST_USER_SET_FEATURES:
-	case VHOST_USER_SET_PROTOCOL_FEATURES:
-	case VHOST_USER_SET_OWNER:
-	case VHOST_USER_SET_MEM_TABLE:
-	case VHOST_USER_SET_LOG_BASE:
-	case VHOST_USER_SET_LOG_FD:
-	case VHOST_USER_SET_VRING_NUM:
-	case VHOST_USER_SET_VRING_ADDR:
-	case VHOST_USER_SET_VRING_BASE:
-	case VHOST_USER_SET_VRING_KICK:
-	case VHOST_USER_SET_VRING_CALL:
-	case VHOST_USER_SET_VRING_ERR:
-	case VHOST_USER_SET_VRING_ENABLE:
-	case VHOST_USER_SEND_RARP:
-	case VHOST_USER_NET_SET_MTU:
-	case VHOST_USER_SET_BACKEND_REQ_FD:
+	if (msg_handler->lock_all_qps) {
 		if (!(dev->flags & VIRTIO_DEV_VDPA_CONFIGURED)) {
 			vhost_user_lock_all_queue_pairs(dev);
 			unlock_required = 1;
 		}
-		break;
-	default:
-		break;
-
 	}
 
 	handled = false;
-- 
2.42.0

Re: [PATCH v2 5/5] vhost: enhance virtqueue access lock asserts

[Thomas Monjalon]

05/12/2023 10:45, David Marchand:
> +#define VHOST_USER_ASSERT_LOCK(dev, vq, id) do { \
> +	RTE_BUILD_BUG_ON(!vhost_message_handlers[id].lock_all_qps); \
> +	vq_assert_lock(dev, vq); \
> +} while (0)

Since "eal: enhance compile-time checks using C11 assert",
it is not allowed to have non-constant check in RTE_BUILD_BUG_ON:

lib/vhost/vhost_user.c:413:25: note: in expansion of macro 'VHOST_USER_ASSERT_LOCK'
lib/vhost/vhost_user.c: In function 'vhost_user_set_vring_addr':
lib/eal/include/rte_common.h:518:56: error: expression in static assertion is not constant
  #define RTE_BUILD_BUG_ON(condition) do { static_assert(!(condition), #condition); } while (0)

I suppose we can make this check at compile-time with few adjustments.
For -rc1, I am dropping this patch.

Re: [PATCH v2 5/5] vhost: enhance virtqueue access lock asserts

[David Marchand]

On Mon, Feb 19, 2024 at 11:52 AM Thomas Monjalon <thomas@monjalon.net> wrote:
>
> 05/12/2023 10:45, David Marchand:
> > +#define VHOST_USER_ASSERT_LOCK(dev, vq, id) do { \
> > +     RTE_BUILD_BUG_ON(!vhost_message_handlers[id].lock_all_qps); \
> > +     vq_assert_lock(dev, vq); \
> > +} while (0)
>
> Since "eal: enhance compile-time checks using C11 assert",
> it is not allowed to have non-constant check in RTE_BUILD_BUG_ON:
>
> lib/vhost/vhost_user.c:413:25: note: in expansion of macro 'VHOST_USER_ASSERT_LOCK'
> lib/vhost/vhost_user.c: In function 'vhost_user_set_vring_addr':
> lib/eal/include/rte_common.h:518:56: error: expression in static assertion is not constant
>   #define RTE_BUILD_BUG_ON(condition) do { static_assert(!(condition), #condition); } while (0)
>
> I suppose we can make this check at compile-time with few adjustments.
> For -rc1, I am dropping this patch.

Iiuc, an array content is not constant (from a compiler pov) unless
the elements are integers.

I suspect there is some gcc-specific implementation that could work,
since with the previous implementation of RTE_BUILD_BUG_ON, this check
was working with both gcc and clang...
But I could not find how to.

I have an alternate solution using enums with the existing macros..
I'll post a new revision.


-- 
David Marchand

[PATCH v3] vhost: enhance virtqueue access lock asserts

[David Marchand]

A simple comment in vhost_user_msg_handler() is not that robust.

Add a lock_all_qps property to message handlers so that their
implementation can add a build check and assert a vq is locked.

Signed-off-by: David Marchand <david.marchand@redhat.com>
---
Changes since v2:
- dropped review tags,
- following use of static_assert() in RTE_BUILD_BUG_ON, reworked build
  check by using enums (one enum is now defined per message type),
- as the added enums must be defined early, moved the definitions of
  handlers at the top of the file,

Changes since v1:
- moved this patch as the last of the series,

---
 lib/vhost/vhost_user.c | 128 +++++++++++++++++++++--------------------
 1 file changed, 66 insertions(+), 62 deletions(-)

diff --git a/lib/vhost/vhost_user.c b/lib/vhost/vhost_user.c
index 3e8a87e517..84dae612c7 100644
--- a/lib/vhost/vhost_user.c
+++ b/lib/vhost/vhost_user.c
@@ -56,14 +56,72 @@
 #define INFLIGHT_ALIGNMENT	64
 #define INFLIGHT_VERSION	0x1
 
-typedef struct vhost_message_handler {
+typedef const struct vhost_message_handler {
 	const char *description;
 	int (*callback)(struct virtio_net **pdev, struct vhu_msg_context *ctx,
 		int main_fd);
 	bool accepts_fd;
+	bool lock_all_qps;
 } vhost_message_handler_t;
 static vhost_message_handler_t vhost_message_handlers[];
 
+#define VHOST_MESSAGE_HANDLERS \
+VHOST_MESSAGE_HANDLER(VHOST_USER_NONE, NULL, false, false) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_GET_FEATURES, vhost_user_get_features, false, false) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_SET_FEATURES, vhost_user_set_features, false, true) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_SET_OWNER, vhost_user_set_owner, false, true) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_RESET_OWNER, vhost_user_reset_owner, false, false) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_SET_MEM_TABLE, vhost_user_set_mem_table, true, true) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_SET_LOG_BASE, vhost_user_set_log_base, true, true) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_SET_LOG_FD, vhost_user_set_log_fd, true, true) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_SET_VRING_NUM, vhost_user_set_vring_num, false, true) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_SET_VRING_ADDR, vhost_user_set_vring_addr, false, true) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_SET_VRING_BASE, vhost_user_set_vring_base, false, true) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_GET_VRING_BASE, vhost_user_get_vring_base, false, false) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_SET_VRING_KICK, vhost_user_set_vring_kick, true, true) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_SET_VRING_CALL, vhost_user_set_vring_call, true, true) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_SET_VRING_ERR, vhost_user_set_vring_err, true, true) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_GET_PROTOCOL_FEATURES, vhost_user_get_protocol_features, \
+	false, false) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_SET_PROTOCOL_FEATURES, vhost_user_set_protocol_features, \
+	false, true) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_GET_QUEUE_NUM, vhost_user_get_queue_num, false, false) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_SET_VRING_ENABLE, vhost_user_set_vring_enable, false, true) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_SEND_RARP, vhost_user_send_rarp, false, true) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_NET_SET_MTU, vhost_user_net_set_mtu, false, true) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_SET_BACKEND_REQ_FD, vhost_user_set_req_fd, true, true) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_IOTLB_MSG, vhost_user_iotlb_msg, false, false) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_GET_CONFIG, vhost_user_get_config, false, false) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_SET_CONFIG, vhost_user_set_config, false, false) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_POSTCOPY_ADVISE, vhost_user_set_postcopy_advise, false, false) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_POSTCOPY_LISTEN, vhost_user_set_postcopy_listen, false, false) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_POSTCOPY_END, vhost_user_postcopy_end, false, false) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_GET_INFLIGHT_FD, vhost_user_get_inflight_fd, false, false) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_SET_INFLIGHT_FD, vhost_user_set_inflight_fd, true, false) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_SET_STATUS, vhost_user_set_status, false, false) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_GET_STATUS, vhost_user_get_status, false, false)
+
+#define VHOST_MESSAGE_HANDLER(id, handler, accepts_fd, lock_all_qps) \
+	id ## _LOCK_ALL_QPS = lock_all_qps,
+enum {
+	VHOST_MESSAGE_HANDLERS
+};
+#undef VHOST_MESSAGE_HANDLER
+
+/* vhost_user_msg_handler() locks all qps based on a handler's lock_all_qps.
+ * Later, a handler may need to ensure the vq has been locked (for example,
+ * when calling lock annotated helpers).
+ *
+ * Note: unfortunately, static_assert() does not see an array content as a
+ * constant expression. Because of this, we can't simply check for
+ * vhost_user_msg_handler[].lock_all_qps.
+ * Instead, define an enum for each handler.
+ */
+#define VHOST_USER_ASSERT_LOCK(dev, vq, id) do { \
+	RTE_BUILD_BUG_ON(id ## _LOCK_ALL_QPS == false); \
+	vq_assert_lock(dev, vq); \
+} while (0)
+
 static int send_vhost_reply(struct virtio_net *dev, int sockfd, struct vhu_msg_context *ctx);
 static int read_vhost_message(struct virtio_net *dev, int sockfd, struct vhu_msg_context *ctx);
 
@@ -400,7 +458,7 @@ vhost_user_set_features(struct virtio_net **pdev,
 			cleanup_vq(vq, 1);
 			cleanup_vq_inflight(dev, vq);
 			/* vhost_user_lock_all_queue_pairs locked all qps */
-			vq_assert_lock(dev, vq);
+			VHOST_USER_ASSERT_LOCK(dev, vq, VHOST_USER_SET_FEATURES);
 			rte_rwlock_write_unlock(&vq->access_lock);
 			free_vq(dev, vq);
 		}
@@ -927,7 +985,7 @@ vhost_user_set_vring_addr(struct virtio_net **pdev,
 	vq = dev->virtqueue[ctx->msg.payload.addr.index];
 
 	/* vhost_user_lock_all_queue_pairs locked all qps */
-	vq_assert_lock(dev, vq);
+	VHOST_USER_ASSERT_LOCK(dev, vq, VHOST_USER_SET_VRING_ADDR);
 
 	access_ok = vq->access_ok;
 
@@ -1442,7 +1500,7 @@ vhost_user_set_mem_table(struct virtio_net **pdev,
 
 		if (vq->desc || vq->avail || vq->used) {
 			/* vhost_user_lock_all_queue_pairs locked all qps */
-			vq_assert_lock(dev, vq);
+			VHOST_USER_ASSERT_LOCK(dev, vq, VHOST_USER_SET_MEM_TABLE);
 
 			/*
 			 * If the memory table got updated, the ring addresses
@@ -2234,7 +2292,7 @@ vhost_user_set_vring_enable(struct virtio_net **pdev,
 	vq = dev->virtqueue[index];
 	if (!(dev->flags & VIRTIO_DEV_VDPA_CONFIGURED)) {
 		/* vhost_user_lock_all_queue_pairs locked all qps */
-		vq_assert_lock(dev, vq);
+		VHOST_USER_ASSERT_LOCK(dev, vq, VHOST_USER_SET_VRING_ENABLE);
 		if (enable && vq->async && vq->async->pkts_inflight_n) {
 			VHOST_CONFIG_LOG(dev->ifname, ERR,
 				"failed to enable vring. Inflight packets must be completed first");
@@ -2838,42 +2896,8 @@ vhost_user_set_status(struct virtio_net **pdev,
 	return RTE_VHOST_MSG_RESULT_OK;
 }
 
-#define VHOST_MESSAGE_HANDLERS \
-VHOST_MESSAGE_HANDLER(VHOST_USER_NONE, NULL, false) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_GET_FEATURES, vhost_user_get_features, false) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_SET_FEATURES, vhost_user_set_features, false) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_SET_OWNER, vhost_user_set_owner, false) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_RESET_OWNER, vhost_user_reset_owner, false) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_SET_MEM_TABLE, vhost_user_set_mem_table, true) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_SET_LOG_BASE, vhost_user_set_log_base, true) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_SET_LOG_FD, vhost_user_set_log_fd, true) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_SET_VRING_NUM, vhost_user_set_vring_num, false) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_SET_VRING_ADDR, vhost_user_set_vring_addr, false) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_SET_VRING_BASE, vhost_user_set_vring_base, false) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_GET_VRING_BASE, vhost_user_get_vring_base, false) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_SET_VRING_KICK, vhost_user_set_vring_kick, true) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_SET_VRING_CALL, vhost_user_set_vring_call, true) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_SET_VRING_ERR, vhost_user_set_vring_err, true) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_GET_PROTOCOL_FEATURES, vhost_user_get_protocol_features, false) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_SET_PROTOCOL_FEATURES, vhost_user_set_protocol_features, false) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_GET_QUEUE_NUM, vhost_user_get_queue_num, false) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_SET_VRING_ENABLE, vhost_user_set_vring_enable, false) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_SEND_RARP, vhost_user_send_rarp, false) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_NET_SET_MTU, vhost_user_net_set_mtu, false) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_SET_BACKEND_REQ_FD, vhost_user_set_req_fd, true) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_IOTLB_MSG, vhost_user_iotlb_msg, false) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_GET_CONFIG, vhost_user_get_config, false) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_SET_CONFIG, vhost_user_set_config, false) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_POSTCOPY_ADVISE, vhost_user_set_postcopy_advise, false) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_POSTCOPY_LISTEN, vhost_user_set_postcopy_listen, false) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_POSTCOPY_END, vhost_user_postcopy_end, false) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_GET_INFLIGHT_FD, vhost_user_get_inflight_fd, false) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_SET_INFLIGHT_FD, vhost_user_set_inflight_fd, true) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_SET_STATUS, vhost_user_set_status, false) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_GET_STATUS, vhost_user_get_status, false)
-
-#define VHOST_MESSAGE_HANDLER(id, handler, accepts_fd) \
-	[id] = { #id, handler, accepts_fd },
+#define VHOST_MESSAGE_HANDLER(id, handler, accepts_fd, lock_all_qps) \
+	[id] = { #id, handler, accepts_fd, id ## _LOCK_ALL_QPS },
 static vhost_message_handler_t vhost_message_handlers[] = {
 	VHOST_MESSAGE_HANDLERS
 };
@@ -3141,31 +3165,11 @@ vhost_user_msg_handler(int vid, int fd)
 	 * inactive, so it is safe. Otherwise taking the access_lock
 	 * would cause a dead lock.
 	 */
-	switch (request) {
-	case VHOST_USER_SET_FEATURES:
-	case VHOST_USER_SET_PROTOCOL_FEATURES:
-	case VHOST_USER_SET_OWNER:
-	case VHOST_USER_SET_MEM_TABLE:
-	case VHOST_USER_SET_LOG_BASE:
-	case VHOST_USER_SET_LOG_FD:
-	case VHOST_USER_SET_VRING_NUM:
-	case VHOST_USER_SET_VRING_ADDR:
-	case VHOST_USER_SET_VRING_BASE:
-	case VHOST_USER_SET_VRING_KICK:
-	case VHOST_USER_SET_VRING_CALL:
-	case VHOST_USER_SET_VRING_ERR:
-	case VHOST_USER_SET_VRING_ENABLE:
-	case VHOST_USER_SEND_RARP:
-	case VHOST_USER_NET_SET_MTU:
-	case VHOST_USER_SET_BACKEND_REQ_FD:
+	if (msg_handler->lock_all_qps) {
 		if (!(dev->flags & VIRTIO_DEV_VDPA_CONFIGURED)) {
 			vhost_user_lock_all_queue_pairs(dev);
 			unlock_required = 1;
 		}
-		break;
-	default:
-		break;
-
 	}
 
 	handled = false;
-- 
2.43.0

Re: [PATCH v3] vhost: enhance virtqueue access lock asserts

[Maxime Coquelin]

On 2/26/24 18:05, David Marchand wrote:
> A simple comment in vhost_user_msg_handler() is not that robust.
> 
> Add a lock_all_qps property to message handlers so that their
> implementation can add a build check and assert a vq is locked.
> 
> Signed-off-by: David Marchand <david.marchand@redhat.com>
> ---
> Changes since v2:
> - dropped review tags,
> - following use of static_assert() in RTE_BUILD_BUG_ON, reworked build
>    check by using enums (one enum is now defined per message type),

Thanks for working on an alternative, it looks good to me:

Reviewed-by: Maxime Coquelin <maxime.coquelin@redhat.com>

Maxime

> - as the added enums must be defined early, moved the definitions of
>    handlers at the top of the file,
> 
> Changes since v1:
> - moved this patch as the last of the series,
> 
> ---
>   lib/vhost/vhost_user.c | 128 +++++++++++++++++++++--------------------
>   1 file changed, 66 insertions(+), 62 deletions(-)
> 
> diff --git a/lib/vhost/vhost_user.c b/lib/vhost/vhost_user.c
> index 3e8a87e517..84dae612c7 100644
> --- a/lib/vhost/vhost_user.c
> +++ b/lib/vhost/vhost_user.c
> @@ -56,14 +56,72 @@
>   #define INFLIGHT_ALIGNMENT	64
>   #define INFLIGHT_VERSION	0x1
>   
> -typedef struct vhost_message_handler {
> +typedef const struct vhost_message_handler {
>   	const char *description;
>   	int (*callback)(struct virtio_net **pdev, struct vhu_msg_context *ctx,
>   		int main_fd);
>   	bool accepts_fd;
> +	bool lock_all_qps;
>   } vhost_message_handler_t;
>   static vhost_message_handler_t vhost_message_handlers[];
>   
> +#define VHOST_MESSAGE_HANDLERS \
> +VHOST_MESSAGE_HANDLER(VHOST_USER_NONE, NULL, false, false) \
> +VHOST_MESSAGE_HANDLER(VHOST_USER_GET_FEATURES, vhost_user_get_features, false, false) \
> +VHOST_MESSAGE_HANDLER(VHOST_USER_SET_FEATURES, vhost_user_set_features, false, true) \
> +VHOST_MESSAGE_HANDLER(VHOST_USER_SET_OWNER, vhost_user_set_owner, false, true) \
> +VHOST_MESSAGE_HANDLER(VHOST_USER_RESET_OWNER, vhost_user_reset_owner, false, false) \
> +VHOST_MESSAGE_HANDLER(VHOST_USER_SET_MEM_TABLE, vhost_user_set_mem_table, true, true) \
> +VHOST_MESSAGE_HANDLER(VHOST_USER_SET_LOG_BASE, vhost_user_set_log_base, true, true) \
> +VHOST_MESSAGE_HANDLER(VHOST_USER_SET_LOG_FD, vhost_user_set_log_fd, true, true) \
> +VHOST_MESSAGE_HANDLER(VHOST_USER_SET_VRING_NUM, vhost_user_set_vring_num, false, true) \
> +VHOST_MESSAGE_HANDLER(VHOST_USER_SET_VRING_ADDR, vhost_user_set_vring_addr, false, true) \
> +VHOST_MESSAGE_HANDLER(VHOST_USER_SET_VRING_BASE, vhost_user_set_vring_base, false, true) \
> +VHOST_MESSAGE_HANDLER(VHOST_USER_GET_VRING_BASE, vhost_user_get_vring_base, false, false) \
> +VHOST_MESSAGE_HANDLER(VHOST_USER_SET_VRING_KICK, vhost_user_set_vring_kick, true, true) \
> +VHOST_MESSAGE_HANDLER(VHOST_USER_SET_VRING_CALL, vhost_user_set_vring_call, true, true) \
> +VHOST_MESSAGE_HANDLER(VHOST_USER_SET_VRING_ERR, vhost_user_set_vring_err, true, true) \
> +VHOST_MESSAGE_HANDLER(VHOST_USER_GET_PROTOCOL_FEATURES, vhost_user_get_protocol_features, \
> +	false, false) \
> +VHOST_MESSAGE_HANDLER(VHOST_USER_SET_PROTOCOL_FEATURES, vhost_user_set_protocol_features, \
> +	false, true) \
> +VHOST_MESSAGE_HANDLER(VHOST_USER_GET_QUEUE_NUM, vhost_user_get_queue_num, false, false) \
> +VHOST_MESSAGE_HANDLER(VHOST_USER_SET_VRING_ENABLE, vhost_user_set_vring_enable, false, true) \
> +VHOST_MESSAGE_HANDLER(VHOST_USER_SEND_RARP, vhost_user_send_rarp, false, true) \
> +VHOST_MESSAGE_HANDLER(VHOST_USER_NET_SET_MTU, vhost_user_net_set_mtu, false, true) \
> +VHOST_MESSAGE_HANDLER(VHOST_USER_SET_BACKEND_REQ_FD, vhost_user_set_req_fd, true, true) \
> +VHOST_MESSAGE_HANDLER(VHOST_USER_IOTLB_MSG, vhost_user_iotlb_msg, false, false) \
> +VHOST_MESSAGE_HANDLER(VHOST_USER_GET_CONFIG, vhost_user_get_config, false, false) \
> +VHOST_MESSAGE_HANDLER(VHOST_USER_SET_CONFIG, vhost_user_set_config, false, false) \
> +VHOST_MESSAGE_HANDLER(VHOST_USER_POSTCOPY_ADVISE, vhost_user_set_postcopy_advise, false, false) \
> +VHOST_MESSAGE_HANDLER(VHOST_USER_POSTCOPY_LISTEN, vhost_user_set_postcopy_listen, false, false) \
> +VHOST_MESSAGE_HANDLER(VHOST_USER_POSTCOPY_END, vhost_user_postcopy_end, false, false) \
> +VHOST_MESSAGE_HANDLER(VHOST_USER_GET_INFLIGHT_FD, vhost_user_get_inflight_fd, false, false) \
> +VHOST_MESSAGE_HANDLER(VHOST_USER_SET_INFLIGHT_FD, vhost_user_set_inflight_fd, true, false) \
> +VHOST_MESSAGE_HANDLER(VHOST_USER_SET_STATUS, vhost_user_set_status, false, false) \
> +VHOST_MESSAGE_HANDLER(VHOST_USER_GET_STATUS, vhost_user_get_status, false, false)
> +
> +#define VHOST_MESSAGE_HANDLER(id, handler, accepts_fd, lock_all_qps) \
> +	id ## _LOCK_ALL_QPS = lock_all_qps,
> +enum {
> +	VHOST_MESSAGE_HANDLERS
> +};
> +#undef VHOST_MESSAGE_HANDLER
> +
> +/* vhost_user_msg_handler() locks all qps based on a handler's lock_all_qps.
> + * Later, a handler may need to ensure the vq has been locked (for example,
> + * when calling lock annotated helpers).
> + *
> + * Note: unfortunately, static_assert() does not see an array content as a
> + * constant expression. Because of this, we can't simply check for
> + * vhost_user_msg_handler[].lock_all_qps.
> + * Instead, define an enum for each handler.
> + */
> +#define VHOST_USER_ASSERT_LOCK(dev, vq, id) do { \
> +	RTE_BUILD_BUG_ON(id ## _LOCK_ALL_QPS == false); \
> +	vq_assert_lock(dev, vq); \
> +} while (0)
> +
>   static int send_vhost_reply(struct virtio_net *dev, int sockfd, struct vhu_msg_context *ctx);
>   static int read_vhost_message(struct virtio_net *dev, int sockfd, struct vhu_msg_context *ctx);
>   
> @@ -400,7 +458,7 @@ vhost_user_set_features(struct virtio_net **pdev,
>   			cleanup_vq(vq, 1);
>   			cleanup_vq_inflight(dev, vq);
>   			/* vhost_user_lock_all_queue_pairs locked all qps */
> -			vq_assert_lock(dev, vq);
> +			VHOST_USER_ASSERT_LOCK(dev, vq, VHOST_USER_SET_FEATURES);
>   			rte_rwlock_write_unlock(&vq->access_lock);
>   			free_vq(dev, vq);
>   		}
> @@ -927,7 +985,7 @@ vhost_user_set_vring_addr(struct virtio_net **pdev,
>   	vq = dev->virtqueue[ctx->msg.payload.addr.index];
>   
>   	/* vhost_user_lock_all_queue_pairs locked all qps */
> -	vq_assert_lock(dev, vq);
> +	VHOST_USER_ASSERT_LOCK(dev, vq, VHOST_USER_SET_VRING_ADDR);
>   
>   	access_ok = vq->access_ok;
>   
> @@ -1442,7 +1500,7 @@ vhost_user_set_mem_table(struct virtio_net **pdev,
>   
>   		if (vq->desc || vq->avail || vq->used) {
>   			/* vhost_user_lock_all_queue_pairs locked all qps */
> -			vq_assert_lock(dev, vq);
> +			VHOST_USER_ASSERT_LOCK(dev, vq, VHOST_USER_SET_MEM_TABLE);
>   
>   			/*
>   			 * If the memory table got updated, the ring addresses
> @@ -2234,7 +2292,7 @@ vhost_user_set_vring_enable(struct virtio_net **pdev,
>   	vq = dev->virtqueue[index];
>   	if (!(dev->flags & VIRTIO_DEV_VDPA_CONFIGURED)) {
>   		/* vhost_user_lock_all_queue_pairs locked all qps */
> -		vq_assert_lock(dev, vq);
> +		VHOST_USER_ASSERT_LOCK(dev, vq, VHOST_USER_SET_VRING_ENABLE);
>   		if (enable && vq->async && vq->async->pkts_inflight_n) {
>   			VHOST_CONFIG_LOG(dev->ifname, ERR,
>   				"failed to enable vring. Inflight packets must be completed first");
> @@ -2838,42 +2896,8 @@ vhost_user_set_status(struct virtio_net **pdev,
>   	return RTE_VHOST_MSG_RESULT_OK;
>   }
>   
> -#define VHOST_MESSAGE_HANDLERS \
> -VHOST_MESSAGE_HANDLER(VHOST_USER_NONE, NULL, false) \
> -VHOST_MESSAGE_HANDLER(VHOST_USER_GET_FEATURES, vhost_user_get_features, false) \
> -VHOST_MESSAGE_HANDLER(VHOST_USER_SET_FEATURES, vhost_user_set_features, false) \
> -VHOST_MESSAGE_HANDLER(VHOST_USER_SET_OWNER, vhost_user_set_owner, false) \
> -VHOST_MESSAGE_HANDLER(VHOST_USER_RESET_OWNER, vhost_user_reset_owner, false) \
> -VHOST_MESSAGE_HANDLER(VHOST_USER_SET_MEM_TABLE, vhost_user_set_mem_table, true) \
> -VHOST_MESSAGE_HANDLER(VHOST_USER_SET_LOG_BASE, vhost_user_set_log_base, true) \
> -VHOST_MESSAGE_HANDLER(VHOST_USER_SET_LOG_FD, vhost_user_set_log_fd, true) \
> -VHOST_MESSAGE_HANDLER(VHOST_USER_SET_VRING_NUM, vhost_user_set_vring_num, false) \
> -VHOST_MESSAGE_HANDLER(VHOST_USER_SET_VRING_ADDR, vhost_user_set_vring_addr, false) \
> -VHOST_MESSAGE_HANDLER(VHOST_USER_SET_VRING_BASE, vhost_user_set_vring_base, false) \
> -VHOST_MESSAGE_HANDLER(VHOST_USER_GET_VRING_BASE, vhost_user_get_vring_base, false) \
> -VHOST_MESSAGE_HANDLER(VHOST_USER_SET_VRING_KICK, vhost_user_set_vring_kick, true) \
> -VHOST_MESSAGE_HANDLER(VHOST_USER_SET_VRING_CALL, vhost_user_set_vring_call, true) \
> -VHOST_MESSAGE_HANDLER(VHOST_USER_SET_VRING_ERR, vhost_user_set_vring_err, true) \
> -VHOST_MESSAGE_HANDLER(VHOST_USER_GET_PROTOCOL_FEATURES, vhost_user_get_protocol_features, false) \
> -VHOST_MESSAGE_HANDLER(VHOST_USER_SET_PROTOCOL_FEATURES, vhost_user_set_protocol_features, false) \
> -VHOST_MESSAGE_HANDLER(VHOST_USER_GET_QUEUE_NUM, vhost_user_get_queue_num, false) \
> -VHOST_MESSAGE_HANDLER(VHOST_USER_SET_VRING_ENABLE, vhost_user_set_vring_enable, false) \
> -VHOST_MESSAGE_HANDLER(VHOST_USER_SEND_RARP, vhost_user_send_rarp, false) \
> -VHOST_MESSAGE_HANDLER(VHOST_USER_NET_SET_MTU, vhost_user_net_set_mtu, false) \
> -VHOST_MESSAGE_HANDLER(VHOST_USER_SET_BACKEND_REQ_FD, vhost_user_set_req_fd, true) \
> -VHOST_MESSAGE_HANDLER(VHOST_USER_IOTLB_MSG, vhost_user_iotlb_msg, false) \
> -VHOST_MESSAGE_HANDLER(VHOST_USER_GET_CONFIG, vhost_user_get_config, false) \
> -VHOST_MESSAGE_HANDLER(VHOST_USER_SET_CONFIG, vhost_user_set_config, false) \
> -VHOST_MESSAGE_HANDLER(VHOST_USER_POSTCOPY_ADVISE, vhost_user_set_postcopy_advise, false) \
> -VHOST_MESSAGE_HANDLER(VHOST_USER_POSTCOPY_LISTEN, vhost_user_set_postcopy_listen, false) \
> -VHOST_MESSAGE_HANDLER(VHOST_USER_POSTCOPY_END, vhost_user_postcopy_end, false) \
> -VHOST_MESSAGE_HANDLER(VHOST_USER_GET_INFLIGHT_FD, vhost_user_get_inflight_fd, false) \
> -VHOST_MESSAGE_HANDLER(VHOST_USER_SET_INFLIGHT_FD, vhost_user_set_inflight_fd, true) \
> -VHOST_MESSAGE_HANDLER(VHOST_USER_SET_STATUS, vhost_user_set_status, false) \
> -VHOST_MESSAGE_HANDLER(VHOST_USER_GET_STATUS, vhost_user_get_status, false)
> -
> -#define VHOST_MESSAGE_HANDLER(id, handler, accepts_fd) \
> -	[id] = { #id, handler, accepts_fd },
> +#define VHOST_MESSAGE_HANDLER(id, handler, accepts_fd, lock_all_qps) \
> +	[id] = { #id, handler, accepts_fd, id ## _LOCK_ALL_QPS },
>   static vhost_message_handler_t vhost_message_handlers[] = {
>   	VHOST_MESSAGE_HANDLERS
>   };
> @@ -3141,31 +3165,11 @@ vhost_user_msg_handler(int vid, int fd)
>   	 * inactive, so it is safe. Otherwise taking the access_lock
>   	 * would cause a dead lock.
>   	 */
> -	switch (request) {
> -	case VHOST_USER_SET_FEATURES:
> -	case VHOST_USER_SET_PROTOCOL_FEATURES:
> -	case VHOST_USER_SET_OWNER:
> -	case VHOST_USER_SET_MEM_TABLE:
> -	case VHOST_USER_SET_LOG_BASE:
> -	case VHOST_USER_SET_LOG_FD:
> -	case VHOST_USER_SET_VRING_NUM:
> -	case VHOST_USER_SET_VRING_ADDR:
> -	case VHOST_USER_SET_VRING_BASE:
> -	case VHOST_USER_SET_VRING_KICK:
> -	case VHOST_USER_SET_VRING_CALL:
> -	case VHOST_USER_SET_VRING_ERR:
> -	case VHOST_USER_SET_VRING_ENABLE:
> -	case VHOST_USER_SEND_RARP:
> -	case VHOST_USER_NET_SET_MTU:
> -	case VHOST_USER_SET_BACKEND_REQ_FD:
> +	if (msg_handler->lock_all_qps) {
>   		if (!(dev->flags & VIRTIO_DEV_VDPA_CONFIGURED)) {
>   			vhost_user_lock_all_queue_pairs(dev);
>   			unlock_required = 1;
>   		}
> -		break;
> -	default:
> -		break;
> -
>   	}
>   
>   	handled = false;

Re: [PATCH v3] vhost: enhance virtqueue access lock asserts

[Stephen Hemminger]

On Mon, 26 Feb 2024 20:40:57 +0100
Maxime Coquelin <maxime.coquelin@redhat.com> wrote:

> > +
> > +/* vhost_user_msg_handler() locks all qps based on a handler's lock_all_qps.
> > + * Later, a handler may need to ensure the vq has been locked (for example,
> > + * when calling lock annotated helpers).
> > + *
> > + * Note: unfortunately, static_assert() does not see an array content as a
> > + * constant expression. Because of this, we can't simply check for
> > + * vhost_user_msg_handler[].lock_all_qps.
> > + * Instead, define an enum for each handler.
> > + */
> > +#define VHOST_USER_ASSERT_LOCK(dev, vq, id) do { \
> > +	RTE_BUILD_BUG_ON(id ## _LOCK_ALL_QPS == false); \

Rather than the opaque output of RTE_BUILD_BUG_ON, please use
static_assert() directly.

[PATCH v4] vhost: enhance virtqueue access lock asserts

[David Marchand]

A simple comment in vhost_user_msg_handler() is not that robust.

Add a lock_all_qps property to message handlers so that their
implementation can add a build check and assert a vq is locked.

Signed-off-by: David Marchand <david.marchand@redhat.com>
Reviewed-by: Maxime Coquelin <maxime.coquelin@redhat.com>
---
Changes since v3:
- directly called static_assert() with improved message,

Changes since v2:
- dropped review tags,
- following use of static_assert() in RTE_BUILD_BUG_ON, reworked build
  check by using enums (one enum is now defined per message type),
- as the added enums must be defined early, moved the definitions of
  handlers at the top of the file,

Changes since v1:
- moved this patch as the last of the series,

---
 lib/vhost/vhost_user.c | 130 +++++++++++++++++++++--------------------
 1 file changed, 68 insertions(+), 62 deletions(-)

diff --git a/lib/vhost/vhost_user.c b/lib/vhost/vhost_user.c
index 3e8a87e517..3aba32c95a 100644
--- a/lib/vhost/vhost_user.c
+++ b/lib/vhost/vhost_user.c
@@ -19,6 +19,7 @@
  * Do not assume received VhostUserMsg fields contain sensible values!
  */
 
+#include <assert.h>
 #include <stdint.h>
 #include <stdio.h>
 #include <stdlib.h>
@@ -56,14 +57,73 @@
 #define INFLIGHT_ALIGNMENT	64
 #define INFLIGHT_VERSION	0x1
 
-typedef struct vhost_message_handler {
+typedef const struct vhost_message_handler {
 	const char *description;
 	int (*callback)(struct virtio_net **pdev, struct vhu_msg_context *ctx,
 		int main_fd);
 	bool accepts_fd;
+	bool lock_all_qps;
 } vhost_message_handler_t;
 static vhost_message_handler_t vhost_message_handlers[];
 
+#define VHOST_MESSAGE_HANDLERS \
+VHOST_MESSAGE_HANDLER(VHOST_USER_NONE, NULL, false, false) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_GET_FEATURES, vhost_user_get_features, false, false) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_SET_FEATURES, vhost_user_set_features, false, true) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_SET_OWNER, vhost_user_set_owner, false, true) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_RESET_OWNER, vhost_user_reset_owner, false, false) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_SET_MEM_TABLE, vhost_user_set_mem_table, true, true) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_SET_LOG_BASE, vhost_user_set_log_base, true, true) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_SET_LOG_FD, vhost_user_set_log_fd, true, true) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_SET_VRING_NUM, vhost_user_set_vring_num, false, true) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_SET_VRING_ADDR, vhost_user_set_vring_addr, false, true) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_SET_VRING_BASE, vhost_user_set_vring_base, false, true) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_GET_VRING_BASE, vhost_user_get_vring_base, false, false) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_SET_VRING_KICK, vhost_user_set_vring_kick, true, true) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_SET_VRING_CALL, vhost_user_set_vring_call, true, true) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_SET_VRING_ERR, vhost_user_set_vring_err, true, true) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_GET_PROTOCOL_FEATURES, vhost_user_get_protocol_features, \
+	false, false) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_SET_PROTOCOL_FEATURES, vhost_user_set_protocol_features, \
+	false, true) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_GET_QUEUE_NUM, vhost_user_get_queue_num, false, false) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_SET_VRING_ENABLE, vhost_user_set_vring_enable, false, true) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_SEND_RARP, vhost_user_send_rarp, false, true) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_NET_SET_MTU, vhost_user_net_set_mtu, false, true) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_SET_BACKEND_REQ_FD, vhost_user_set_req_fd, true, true) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_IOTLB_MSG, vhost_user_iotlb_msg, false, false) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_GET_CONFIG, vhost_user_get_config, false, false) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_SET_CONFIG, vhost_user_set_config, false, false) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_POSTCOPY_ADVISE, vhost_user_set_postcopy_advise, false, false) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_POSTCOPY_LISTEN, vhost_user_set_postcopy_listen, false, false) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_POSTCOPY_END, vhost_user_postcopy_end, false, false) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_GET_INFLIGHT_FD, vhost_user_get_inflight_fd, false, false) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_SET_INFLIGHT_FD, vhost_user_set_inflight_fd, true, false) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_SET_STATUS, vhost_user_set_status, false, false) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_GET_STATUS, vhost_user_get_status, false, false)
+
+#define VHOST_MESSAGE_HANDLER(id, handler, accepts_fd, lock_all_qps) \
+	id ## _LOCK_ALL_QPS = lock_all_qps,
+enum {
+	VHOST_MESSAGE_HANDLERS
+};
+#undef VHOST_MESSAGE_HANDLER
+
+/* vhost_user_msg_handler() locks all qps based on a handler's lock_all_qps.
+ * Later, a handler may need to ensure the vq has been locked (for example,
+ * when calling lock annotated helpers).
+ *
+ * Note: unfortunately, static_assert() does not see an array content as a
+ * constant expression. Because of this, we can't simply check for
+ * vhost_user_msg_handler[].lock_all_qps.
+ * Instead, define an enum for each handler.
+ */
+#define VHOST_USER_ASSERT_LOCK(dev, vq, id) do { \
+	static_assert(id ## _LOCK_ALL_QPS == true, \
+		#id " handler is not declared as locking all queue pairs"); \
+	vq_assert_lock(dev, vq); \
+} while (0)
+
 static int send_vhost_reply(struct virtio_net *dev, int sockfd, struct vhu_msg_context *ctx);
 static int read_vhost_message(struct virtio_net *dev, int sockfd, struct vhu_msg_context *ctx);
 
@@ -400,7 +460,7 @@ vhost_user_set_features(struct virtio_net **pdev,
 			cleanup_vq(vq, 1);
 			cleanup_vq_inflight(dev, vq);
 			/* vhost_user_lock_all_queue_pairs locked all qps */
-			vq_assert_lock(dev, vq);
+			VHOST_USER_ASSERT_LOCK(dev, vq, VHOST_USER_SET_FEATURES);
 			rte_rwlock_write_unlock(&vq->access_lock);
 			free_vq(dev, vq);
 		}
@@ -927,7 +987,7 @@ vhost_user_set_vring_addr(struct virtio_net **pdev,
 	vq = dev->virtqueue[ctx->msg.payload.addr.index];
 
 	/* vhost_user_lock_all_queue_pairs locked all qps */
-	vq_assert_lock(dev, vq);
+	VHOST_USER_ASSERT_LOCK(dev, vq, VHOST_USER_SET_VRING_ADDR);
 
 	access_ok = vq->access_ok;
 
@@ -1442,7 +1502,7 @@ vhost_user_set_mem_table(struct virtio_net **pdev,
 
 		if (vq->desc || vq->avail || vq->used) {
 			/* vhost_user_lock_all_queue_pairs locked all qps */
-			vq_assert_lock(dev, vq);
+			VHOST_USER_ASSERT_LOCK(dev, vq, VHOST_USER_SET_MEM_TABLE);
 
 			/*
 			 * If the memory table got updated, the ring addresses
@@ -2234,7 +2294,7 @@ vhost_user_set_vring_enable(struct virtio_net **pdev,
 	vq = dev->virtqueue[index];
 	if (!(dev->flags & VIRTIO_DEV_VDPA_CONFIGURED)) {
 		/* vhost_user_lock_all_queue_pairs locked all qps */
-		vq_assert_lock(dev, vq);
+		VHOST_USER_ASSERT_LOCK(dev, vq, VHOST_USER_SET_VRING_ENABLE);
 		if (enable && vq->async && vq->async->pkts_inflight_n) {
 			VHOST_CONFIG_LOG(dev->ifname, ERR,
 				"failed to enable vring. Inflight packets must be completed first");
@@ -2838,42 +2898,8 @@ vhost_user_set_status(struct virtio_net **pdev,
 	return RTE_VHOST_MSG_RESULT_OK;
 }
 
-#define VHOST_MESSAGE_HANDLERS \
-VHOST_MESSAGE_HANDLER(VHOST_USER_NONE, NULL, false) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_GET_FEATURES, vhost_user_get_features, false) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_SET_FEATURES, vhost_user_set_features, false) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_SET_OWNER, vhost_user_set_owner, false) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_RESET_OWNER, vhost_user_reset_owner, false) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_SET_MEM_TABLE, vhost_user_set_mem_table, true) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_SET_LOG_BASE, vhost_user_set_log_base, true) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_SET_LOG_FD, vhost_user_set_log_fd, true) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_SET_VRING_NUM, vhost_user_set_vring_num, false) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_SET_VRING_ADDR, vhost_user_set_vring_addr, false) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_SET_VRING_BASE, vhost_user_set_vring_base, false) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_GET_VRING_BASE, vhost_user_get_vring_base, false) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_SET_VRING_KICK, vhost_user_set_vring_kick, true) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_SET_VRING_CALL, vhost_user_set_vring_call, true) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_SET_VRING_ERR, vhost_user_set_vring_err, true) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_GET_PROTOCOL_FEATURES, vhost_user_get_protocol_features, false) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_SET_PROTOCOL_FEATURES, vhost_user_set_protocol_features, false) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_GET_QUEUE_NUM, vhost_user_get_queue_num, false) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_SET_VRING_ENABLE, vhost_user_set_vring_enable, false) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_SEND_RARP, vhost_user_send_rarp, false) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_NET_SET_MTU, vhost_user_net_set_mtu, false) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_SET_BACKEND_REQ_FD, vhost_user_set_req_fd, true) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_IOTLB_MSG, vhost_user_iotlb_msg, false) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_GET_CONFIG, vhost_user_get_config, false) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_SET_CONFIG, vhost_user_set_config, false) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_POSTCOPY_ADVISE, vhost_user_set_postcopy_advise, false) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_POSTCOPY_LISTEN, vhost_user_set_postcopy_listen, false) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_POSTCOPY_END, vhost_user_postcopy_end, false) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_GET_INFLIGHT_FD, vhost_user_get_inflight_fd, false) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_SET_INFLIGHT_FD, vhost_user_set_inflight_fd, true) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_SET_STATUS, vhost_user_set_status, false) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_GET_STATUS, vhost_user_get_status, false)
-
-#define VHOST_MESSAGE_HANDLER(id, handler, accepts_fd) \
-	[id] = { #id, handler, accepts_fd },
+#define VHOST_MESSAGE_HANDLER(id, handler, accepts_fd, lock_all_qps) \
+	[id] = { #id, handler, accepts_fd, id ## _LOCK_ALL_QPS },
 static vhost_message_handler_t vhost_message_handlers[] = {
 	VHOST_MESSAGE_HANDLERS
 };
@@ -3141,31 +3167,11 @@ vhost_user_msg_handler(int vid, int fd)
 	 * inactive, so it is safe. Otherwise taking the access_lock
 	 * would cause a dead lock.
 	 */
-	switch (request) {
-	case VHOST_USER_SET_FEATURES:
-	case VHOST_USER_SET_PROTOCOL_FEATURES:
-	case VHOST_USER_SET_OWNER:
-	case VHOST_USER_SET_MEM_TABLE:
-	case VHOST_USER_SET_LOG_BASE:
-	case VHOST_USER_SET_LOG_FD:
-	case VHOST_USER_SET_VRING_NUM:
-	case VHOST_USER_SET_VRING_ADDR:
-	case VHOST_USER_SET_VRING_BASE:
-	case VHOST_USER_SET_VRING_KICK:
-	case VHOST_USER_SET_VRING_CALL:
-	case VHOST_USER_SET_VRING_ERR:
-	case VHOST_USER_SET_VRING_ENABLE:
-	case VHOST_USER_SEND_RARP:
-	case VHOST_USER_NET_SET_MTU:
-	case VHOST_USER_SET_BACKEND_REQ_FD:
+	if (msg_handler->lock_all_qps) {
 		if (!(dev->flags & VIRTIO_DEV_VDPA_CONFIGURED)) {
 			vhost_user_lock_all_queue_pairs(dev);
 			unlock_required = 1;
 		}
-		break;
-	default:
-		break;
-
 	}
 
 	handled = false;
-- 
2.43.0

Re: [PATCH v4] vhost: enhance virtqueue access lock asserts

[Maxime Coquelin]

On 2/27/24 11:39, David Marchand wrote:
> A simple comment in vhost_user_msg_handler() is not that robust.
> 
> Add a lock_all_qps property to message handlers so that their
> implementation can add a build check and assert a vq is locked.
> 
> Signed-off-by: David Marchand <david.marchand@redhat.com>
> Reviewed-by: Maxime Coquelin <maxime.coquelin@redhat.com>
> ---
> Changes since v3:
> - directly called static_assert() with improved message,
> 
> Changes since v2:
> - dropped review tags,
> - following use of static_assert() in RTE_BUILD_BUG_ON, reworked build
>    check by using enums (one enum is now defined per message type),
> - as the added enums must be defined early, moved the definitions of
>    handlers at the top of the file,
> 
> Changes since v1:
> - moved this patch as the last of the series,
> 
> ---
>   lib/vhost/vhost_user.c | 130 +++++++++++++++++++++--------------------
>   1 file changed, 68 insertions(+), 62 deletions(-)
> 

Reviewed-by: Maxime Coquelin <maxime.coquelin@redhat.com>

Thanks,
Maxime

Re: [PATCH v4] vhost: enhance virtqueue access lock asserts

[David Marchand]

On Tue, Feb 27, 2024 at 11:39 AM David Marchand
<david.marchand@redhat.com> wrote:
>
> A simple comment in vhost_user_msg_handler() is not that robust.
>
> Add a lock_all_qps property to message handlers so that their
> implementation can add a build check and assert a vq is locked.
>
> Signed-off-by: David Marchand <david.marchand@redhat.com>
> Reviewed-by: Maxime Coquelin <maxime.coquelin@redhat.com>
> ---
> Changes since v3:
> - directly called static_assert() with improved message,
>
> Changes since v2:
> - dropped review tags,
> - following use of static_assert() in RTE_BUILD_BUG_ON, reworked build
>   check by using enums (one enum is now defined per message type),
> - as the added enums must be defined early, moved the definitions of
>   handlers at the top of the file,
>
> Changes since v1:
> - moved this patch as the last of the series,

Applied, thanks.


-- 
David Marchand

Re: [PATCH v2 1/5] vhost: fix virtqueue access check in datapath

[Maxime Coquelin]

On 12/5/23 10:45, David Marchand wrote:
> Now that a r/w lock is used, the access_ok field should only be updated
> under a write lock.
> 
> Since the datapath code only takes a read lock on the virtqueue to check
> access_ok, this lock must be released and a write lock taken before
> calling vring_translate().
> 
> Fixes: 03f77d66d966 ("vhost: change virtqueue access lock to a read/write one")
> Cc: stable@dpdk.org
> 
> Signed-off-by: David Marchand <david.marchand@redhat.com>
> Acked-by: Eelco Chaudron <echaudro@redhat.com>
> Reviewed-by: Maxime Coquelin <maxime.coquelin@redhat.com>
> ---
>   lib/vhost/virtio_net.c | 60 +++++++++++++++++++++++++++++++-----------
>   1 file changed, 44 insertions(+), 16 deletions(-)
> 
> diff --git a/lib/vhost/virtio_net.c b/lib/vhost/virtio_net.c
> index 8af20f1487..d00f4b03aa 100644
> --- a/lib/vhost/virtio_net.c
> +++ b/lib/vhost/virtio_net.c
> @@ -1696,6 +1696,17 @@ virtio_dev_rx_packed(struct virtio_net *dev,
>   	return pkt_idx;
>   }
>   
> +static void
> +virtio_dev_vring_translate(struct virtio_net *dev, struct vhost_virtqueue *vq)
> +{
> +	rte_rwlock_write_lock(&vq->access_lock);
> +	vhost_user_iotlb_rd_lock(vq);
> +	if (!vq->access_ok)
> +		vring_translate(dev, vq);
> +	vhost_user_iotlb_rd_unlock(vq);
> +	rte_rwlock_write_unlock(&vq->access_lock);
> +}
> +
>   static __rte_always_inline uint32_t
>   virtio_dev_rx(struct virtio_net *dev, struct vhost_virtqueue *vq,
>   	struct rte_mbuf **pkts, uint32_t count)
> @@ -1710,9 +1721,13 @@ virtio_dev_rx(struct virtio_net *dev, struct vhost_virtqueue *vq,
>   
>   	vhost_user_iotlb_rd_lock(vq);
>   
> -	if (unlikely(!vq->access_ok))
> -		if (unlikely(vring_translate(dev, vq) < 0))
> -			goto out;
> +	if (unlikely(!vq->access_ok)) {
> +		vhost_user_iotlb_rd_unlock(vq);
> +		rte_rwlock_read_unlock(&vq->access_lock);
> +
> +		virtio_dev_vring_translate(dev, vq);
> +		goto out_no_unlock;
> +	}
>   
>   	count = RTE_MIN((uint32_t)MAX_PKT_BURST, count);
>   	if (count == 0)
> @@ -1731,6 +1746,7 @@ virtio_dev_rx(struct virtio_net *dev, struct vhost_virtqueue *vq,
>   out_access_unlock:
>   	rte_rwlock_read_unlock(&vq->access_lock);
>   
> +out_no_unlock:
>   	return nb_tx;
>   }
>   
> @@ -2528,9 +2544,13 @@ virtio_dev_rx_async_submit(struct virtio_net *dev, struct vhost_virtqueue *vq,
>   
>   	vhost_user_iotlb_rd_lock(vq);
>   
> -	if (unlikely(!vq->access_ok))
> -		if (unlikely(vring_translate(dev, vq) < 0))
> -			goto out;
> +	if (unlikely(!vq->access_ok)) {
> +		vhost_user_iotlb_rd_unlock(vq);
> +		rte_rwlock_read_unlock(&vq->access_lock);
> +
> +		virtio_dev_vring_translate(dev, vq);
> +		goto out_no_unlock;
> +	}
>   
>   	count = RTE_MIN((uint32_t)MAX_PKT_BURST, count);
>   	if (count == 0)
> @@ -2551,6 +2571,7 @@ virtio_dev_rx_async_submit(struct virtio_net *dev, struct vhost_virtqueue *vq,
>   out_access_unlock:
>   	rte_rwlock_write_unlock(&vq->access_lock);
>   
> +out_no_unlock:
>   	return nb_tx;
>   }
>   
> @@ -3581,11 +3602,13 @@ rte_vhost_dequeue_burst(int vid, uint16_t queue_id,
>   
>   	vhost_user_iotlb_rd_lock(vq);
>   
> -	if (unlikely(!vq->access_ok))
> -		if (unlikely(vring_translate(dev, vq) < 0)) {
> -			count = 0;
> -			goto out;
> -		}
> +	if (unlikely(!vq->access_ok)) {
> +		vhost_user_iotlb_rd_unlock(vq);
> +		rte_rwlock_read_unlock(&vq->access_lock);
> +
> +		virtio_dev_vring_translate(dev, vq);
> +		goto out_no_unlock;
> +	}
>   
>   	/*
>   	 * Construct a RARP broadcast packet, and inject it to the "pkts"
> @@ -3646,6 +3669,7 @@ rte_vhost_dequeue_burst(int vid, uint16_t queue_id,
>   	if (unlikely(rarp_mbuf != NULL))
>   		count += 1;
>   
> +out_no_unlock:
>   	return count;
>   }
>   
> @@ -4196,11 +4220,14 @@ rte_vhost_async_try_dequeue_burst(int vid, uint16_t queue_id,
>   
>   	vhost_user_iotlb_rd_lock(vq);
>   
> -	if (unlikely(vq->access_ok == 0))
> -		if (unlikely(vring_translate(dev, vq) < 0)) {
> -			count = 0;
> -			goto out;
> -		}
> +	if (unlikely(vq->access_ok == 0)) {
> +		vhost_user_iotlb_rd_unlock(vq);
> +		rte_rwlock_read_unlock(&vq->access_lock);
> +
> +		virtio_dev_vring_translate(dev, vq);
> +		count = 0;
> +		goto out_no_unlock;
> +	}
>   
>   	/*
>   	 * Construct a RARP broadcast packet, and inject it to the "pkts"
> @@ -4266,5 +4293,6 @@ rte_vhost_async_try_dequeue_burst(int vid, uint16_t queue_id,
>   	if (unlikely(rarp_mbuf != NULL))
>   		count += 1;
>   
> +out_no_unlock:
>   	return count;
>   }

Series applied to next-virtio/for-next-net

Thanks,
Maxime