The VIRTIO_RING_F_EVENT_IDX feature of split ring might
be broken, as the value of signalled_used is invalid
after live migration, start up and virtio driver reload.
This patch fixes it by using signalled_used_valid.
In addition, this patch makes the VIRTIO_RING_F_EVENT_IDX
implementation of split ring match kernel backend to suppress
more interrupts.
Fixes: e37ff954405a ("vhost: support virtqueue interrupt/notification
suppression")
Cc: sta...@dpdk.org
Signed-off-by: Jiayu Hu <jiayu...@intel.com>
---
change in v2:
- fix virtio-net driver reload
lib/librte_vhost/vhost.h | 12 ++++++++----
lib/librte_vhost/vhost_user.c | 2 ++
2 files changed, 10 insertions(+), 4 deletions(-)
diff --git a/lib/librte_vhost/vhost.h b/lib/librte_vhost/vhost.h
index f008ec4..e9138df 100644
--- a/lib/librte_vhost/vhost.h
+++ b/lib/librte_vhost/vhost.h
@@ -633,16 +633,20 @@ vhost_vring_call_split(struct virtio_net *dev, struct
vhost_virtqueue *vq)
if (dev->features & (1ULL << VIRTIO_RING_F_EVENT_IDX)) {
uint16_t old = vq->signalled_used;
uint16_t new = vq->last_used_idx;
+ bool signalled_used_valid = vq->signalled_used_valid;
+
+ vq->signalled_used = new;
+ vq->signalled_used_valid = true;
VHOST_LOG_DEBUG(VHOST_DATA, "%s: used_event_idx=%d, old=%d,
new=%d\n",
__func__,
vhost_used_event(vq),
old, new);
- if (vhost_need_event(vhost_used_event(vq), new, old)
- && (vq->callfd >= 0)) {
- vq->signalled_used = vq->last_used_idx;
+
+ if ((vhost_need_event(vhost_used_event(vq), new, old) &&
+ (vq->callfd >= 0)) ||
+ unlikely(!signalled_used_valid))
eventfd_write(vq->callfd, (eventfd_t) 1);
- }
} else {
/* Kick the guest if necessary. */
if (!(vq->avail->flags & VRING_AVAIL_F_NO_INTERRUPT)
diff --git a/lib/librte_vhost/vhost_user.c b/lib/librte_vhost/vhost_user.c
index 36c0c67..01a8d80 100644
--- a/lib/librte_vhost/vhost_user.c
+++ b/lib/librte_vhost/vhost_user.c
@@ -1298,6 +1298,8 @@ vhost_user_get_vring_base(struct virtio_net **pdev,
vq->callfd = VIRTIO_UNINITIALIZED_EVENTFD;
+ vq->signalled_used_valid = false;
+
if (dev->dequeue_zero_copy)
free_zmbufs(vq);
if (vq_is_packed(dev)) {
--
2.7.4
