在 2021/3/16 上午3:48, Eugenio Pérez 写道:
Signed-off-by: Eugenio Pérez <[email protected]> --- hw/virtio/vhost-shadow-virtqueue.c | 28 +++++++++++++++++++++++++++- 1 file changed, 27 insertions(+), 1 deletion(-)diff --git a/hw/virtio/vhost-shadow-virtqueue.c b/hw/virtio/vhost-shadow-virtqueue.c index 7df98fc43f..e3879a4622 100644 --- a/hw/virtio/vhost-shadow-virtqueue.c +++ b/hw/virtio/vhost-shadow-virtqueue.c @@ -71,10 +71,35 @@ typedef struct VhostShadowVirtqueue { /* Next head to consume from device */ uint16_t used_idx;+ /* Cache for the exposed notification flag */+ bool notification; + /* Descriptors copied from guest */ vring_desc_t descs[]; } VhostShadowVirtqueue;+static void vhost_shadow_vq_set_notification(VhostShadowVirtqueue *svq,+ bool enable) +{ + uint16_t notification_flag; + + if (svq->notification == enable) { + return; + } + + notification_flag = virtio_tswap16(svq->vdev, VRING_AVAIL_F_NO_INTERRUPT); + + svq->notification = enable; + if (enable) { + svq->vring.avail->flags &= ~notification_flag; + } else { + svq->vring.avail->flags |= notification_flag; + } + + /* Make sure device reads our flag */ + smp_mb();
This is a hint, so we don't need memory barrier here. Thanks
+} + static void vhost_vring_write_descs(VhostShadowVirtqueue *svq, const struct iovec *iovec, size_t num, bool more_descs, bool write) @@ -251,7 +276,7 @@ static void vhost_shadow_vq_handle_call_no_test(EventNotifier *n) do { unsigned i = 0;- /* TODO: Use VRING_AVAIL_F_NO_INTERRUPT */+ vhost_shadow_vq_set_notification(svq, false); while (true) { g_autofree VirtQueueElement *elem = vhost_shadow_vq_get_buf(svq); if (!elem) { @@ -269,6 +294,7 @@ static void vhost_shadow_vq_handle_call_no_test(EventNotifier *n) svq->masked_notifier.signaled = true; event_notifier_set(svq->masked_notifier.n); } + vhost_shadow_vq_set_notification(svq, true); } while (vhost_shadow_vq_more_used(svq));if (masked_notifier) {
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