[PATCH v2] vhost: add runtime locking check in unsafe APIs

[Maxime Coquelin]

This patch adds runtime checks in unsafe Vhost async APIs,
to ensure the access lock is taken.

The detection won't work every time, as another thread
could take the lock, but it would help to detect misuse
of these unsafe API.

Signed-off-by: Maxime Coquelin <maxime.coque...@redhat.com>
---
 lib/vhost/vhost.c      | 18 ++++++++++++++++++
 lib/vhost/virtio_net.c |  6 ++++++
 2 files changed, 24 insertions(+)

diff --git a/lib/vhost/vhost.c b/lib/vhost/vhost.c
index df0bb9d043..39cbeb415c 100644
--- a/lib/vhost/vhost.c
+++ b/lib/vhost/vhost.c
@@ -1732,6 +1732,12 @@ rte_vhost_async_channel_register_thread_unsafe(int vid, 
uint16_t queue_id)
        if (unlikely(vq == NULL || !dev->async_copy))
                return -1;
 
+       if (unlikely(!rte_spinlock_is_locked(&vq->access_lock))) {
+               VHOST_LOG_CONFIG(ERR, "(%s) %s() called without access lock 
taken.\n",
+                               dev->ifname, __func__);
+               return -1;
+       }
+
        return async_channel_register(vid, queue_id);
 }
 
@@ -1796,6 +1802,12 @@ rte_vhost_async_channel_unregister_thread_unsafe(int 
vid, uint16_t queue_id)
        if (vq == NULL)
                return -1;
 
+       if (unlikely(!rte_spinlock_is_locked(&vq->access_lock))) {
+               VHOST_LOG_CONFIG(ERR, "(%s) %s() called without access lock 
taken.\n",
+                               dev->ifname, __func__);
+               return -1;
+       }
+
        if (!vq->async)
                return 0;
 
@@ -1925,6 +1937,12 @@ rte_vhost_async_get_inflight_thread_unsafe(int vid, 
uint16_t queue_id)
        if (vq == NULL)
                return ret;
 
+       if (unlikely(!rte_spinlock_is_locked(&vq->access_lock))) {
+               VHOST_LOG_CONFIG(ERR, "(%s) %s() called without access lock 
taken.\n",
+                               dev->ifname, __func__);
+               return -1;
+       }
+
        if (!vq->async)
                return ret;
 
diff --git a/lib/vhost/virtio_net.c b/lib/vhost/virtio_net.c
index 5f432b0d77..59163bc165 100644
--- a/lib/vhost/virtio_net.c
+++ b/lib/vhost/virtio_net.c
@@ -2091,6 +2091,12 @@ rte_vhost_clear_queue_thread_unsafe(int vid, uint16_t 
queue_id,
 
        vq = dev->virtqueue[queue_id];
 
+       if (unlikely(!rte_spinlock_is_locked(&vq->access_lock))) {
+               VHOST_LOG_DATA(ERR, "(%s) %s() called without access lock 
taken.\n",
+                               dev->ifname, __func__);
+               return -1;
+       }
+
        if (unlikely(!vq->async)) {
                VHOST_LOG_DATA(ERR, "(%s) %s: async not registered for queue id 
%d.\n",
                        dev->ifname, __func__, queue_id);
-- 
2.35.1