From 01f8beacea2a31edb6c270653052bea2778ae65d Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Eugenio=20P=C3=A9rez?= Date: Thu, 20 Oct 2022 17:52:49 +0200 Subject: [PATCH] vhost: toggle device callbacks using used event idx MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Actually use the new field of the used ring and tell the device if SVQ wants to be notified. The code is not reachable at the moment. Reviewed-by: Michael S. Tsirkin Signed-off-by: Eugenio Pérez Signed-off-by: Jason Wang --- hw/virtio/vhost-shadow-virtqueue.c | 18 +++++++++++++++--- 1 file changed, 15 insertions(+), 3 deletions(-) diff --git a/hw/virtio/vhost-shadow-virtqueue.c b/hw/virtio/vhost-shadow-virtqueue.c index a518f84772..f5c0fad3fc 100644 --- a/hw/virtio/vhost-shadow-virtqueue.c +++ b/hw/virtio/vhost-shadow-virtqueue.c @@ -369,15 +369,27 @@ static bool vhost_svq_more_used(VhostShadowVirtqueue *svq) */ static bool vhost_svq_enable_notification(VhostShadowVirtqueue *svq) { - svq->vring.avail->flags &= ~cpu_to_le16(VRING_AVAIL_F_NO_INTERRUPT); - /* Make sure the flag is written before the read of used_idx */ + if (virtio_vdev_has_feature(svq->vdev, VIRTIO_RING_F_EVENT_IDX)) { + uint16_t *used_event = (uint16_t *)&svq->vring.avail->ring[svq->vring.num]; + *used_event = svq->shadow_used_idx; + } else { + svq->vring.avail->flags &= ~cpu_to_le16(VRING_AVAIL_F_NO_INTERRUPT); + } + + /* Make sure the event is enabled before the read of used_idx */ smp_mb(); return !vhost_svq_more_used(svq); } static void vhost_svq_disable_notification(VhostShadowVirtqueue *svq) { - svq->vring.avail->flags |= cpu_to_le16(VRING_AVAIL_F_NO_INTERRUPT); + /* + * No need to disable notification in the event idx case, since used event + * index is already an index too far away. + */ + if (!virtio_vdev_has_feature(svq->vdev, VIRTIO_RING_F_EVENT_IDX)) { + svq->vring.avail->flags |= cpu_to_le16(VRING_AVAIL_F_NO_INTERRUPT); + } } static uint16_t vhost_svq_last_desc_of_chain(const VhostShadowVirtqueue *svq,