From 22a6840ff282727df3e3c745d92d764c7081f49b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Eugenio=20P=C3=A9rez?= <eperezma@redhat.com>
Date: Thu, 20 Oct 2022 17:52:50 +0200
Subject: [PATCH] vhost: use avail event idx on vhost_svq_kick
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So SVQ code knows if an event is needed.
The code is not reachable at the moment.
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
---
hw/virtio/vhost-shadow-virtqueue.c | 12 +++++++++++-
1 file changed, 11 insertions(+), 1 deletion(-)
diff --git a/hw/virtio/vhost-shadow-virtqueue.c b/hw/virtio/vhost-shadow-virtqueue.c
index f5c0fad3fc..f306ebef72 100644
--- a/hw/virtio/vhost-shadow-virtqueue.c
+++ b/hw/virtio/vhost-shadow-virtqueue.c
@@ -218,12 +218,22 @@ static bool vhost_svq_add_split(VhostShadowVirtqueue *svq,
static void vhost_svq_kick(VhostShadowVirtqueue *svq)
{
+ bool needs_kick;
+
/*
* We need to expose the available array entries before checking the used
* flags
*/
smp_mb();
- if (svq->vring.used->flags & VRING_USED_F_NO_NOTIFY) {
+
+ if (virtio_vdev_has_feature(svq->vdev, VIRTIO_RING_F_EVENT_IDX)) {
+ uint16_t avail_event = *(uint16_t *)(&svq->vring.used->ring[svq->vring.num]);
+ needs_kick = vring_need_event(avail_event, svq->shadow_avail_idx, svq->shadow_avail_idx - 1);
+ } else {
+ needs_kick = !(svq->vring.used->flags & VRING_USED_F_NO_NOTIFY);
+ }
+
+ if (!needs_kick) {
return;
}