Hi Changpeng, On 10/12/22 08:40, Changpeng Liu wrote:
Vhost-user library locks all VQ's access lock when processing vring based messages, such as SET_VRING_KICK and SET_VRING_CALL, and the data processing thread may already be started, e.g: SPDK vhost-blk and vhost-scsi will start the data processing thread when one vring is ready, then deadlock may happen when SPDK is posting interrupts to VM. Here, we add a new API which allows caller to try again later for this case.Bugzilla ID: 1015 Fixes: c5736998305d ("vhost: fix missing virtqueue lock protection") Signed-off-by: Changpeng Liu <[email protected]> --- lib/vhost/rte_vhost.h | 15 +++++++++++++++ lib/vhost/version.map | 3 +++ lib/vhost/vhost.c | 30 ++++++++++++++++++++++++++++++ 3 files changed, 48 insertions(+) diff --git a/lib/vhost/rte_vhost.h b/lib/vhost/rte_vhost.h index bb7d86a432..d22b25cd4e 100644 --- a/lib/vhost/rte_vhost.h +++ b/lib/vhost/rte_vhost.h @@ -909,6 +909,21 @@ rte_vhost_clr_inflight_desc_packed(int vid, uint16_t vring_idx, */ int rte_vhost_vring_call(int vid, uint16_t vring_idx);+/**+ * Notify the guest that used descriptors have been added to the vring. This + * function acts as a memory barrier. This function will return -EAGAIN when + * vq's access lock is held by other thread, user should try again later. + * + * @param vid + * vhost device ID + * @param vring_idx + * vring index + * @return + * 0 on success, -1 on failure, -EAGAIN for another retry + */ +__rte_experimental +int rte_vhost_vring_call_nonblock(int vid, uint16_t vring_idx); + /** * Get vhost RX queue avail count. * diff --git a/lib/vhost/version.map b/lib/vhost/version.map index 7a00b65740..c8c44b8326 100644 --- a/lib/vhost/version.map +++ b/lib/vhost/version.map @@ -94,6 +94,9 @@ EXPERIMENTAL { rte_vhost_async_try_dequeue_burst; rte_vhost_driver_get_vdpa_dev_type; rte_vhost_clear_queue; + + # added in 22.11 + rte_vhost_vring_call_nonblock; };INTERNAL {diff --git a/lib/vhost/vhost.c b/lib/vhost/vhost.c index 8740aa2788..ed6efb003f 100644 --- a/lib/vhost/vhost.c +++ b/lib/vhost/vhost.c @@ -1317,6 +1317,36 @@ rte_vhost_vring_call(int vid, uint16_t vring_idx) return 0; }+int+rte_vhost_vring_call_nonblock(int vid, uint16_t vring_idx) +{ + struct virtio_net *dev; + struct vhost_virtqueue *vq; + + dev = get_device(vid); + if (!dev) + return -1; + + if (vring_idx >= VHOST_MAX_VRING) + return -1; + + vq = dev->virtqueue[vring_idx]; + if (!vq) + return -1; + + if (!rte_spinlock_trylock(&vq->access_lock)) + return -EAGAIN; + + if (vq_is_packed(dev)) + vhost_vring_call_packed(dev, vq); + else + vhost_vring_call_split(dev, vq); + + rte_spinlock_unlock(&vq->access_lock); + + return 0; +} + uint16_t rte_vhost_avail_entries(int vid, uint16_t queue_id) {
Reviewed-by: Maxime Coquelin <[email protected]> Thanks, Maxime
