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[RFC v2 13/13] vhost: Use VRING_AVAIL_F_NO_INTERRUPT at device call on s
From: |
Eugenio Pérez |
Subject: |
[RFC v2 13/13] vhost: Use VRING_AVAIL_F_NO_INTERRUPT at device call on shadow virtqueue |
Date: |
Mon, 15 Mar 2021 20:48:42 +0100 |
Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
---
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();
+}
+
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) {
--
2.27.0
- Re: [RFC v2 12/13] vhost: Check for device VRING_USED_F_NO_NOTIFY at shadow virtqueue kick, (continued)
- [RFC v2 11/13] vhost: Shadow virtqueue buffers forwarding, Eugenio Pérez, 2021/03/15
- Re: [RFC v2 11/13] vhost: Shadow virtqueue buffers forwarding, Jason Wang, 2021/03/16
- Re: [RFC v2 11/13] vhost: Shadow virtqueue buffers forwarding, Eugenio Perez Martin, 2021/03/16
- Re: [RFC v2 11/13] vhost: Shadow virtqueue buffers forwarding, Jason Wang, 2021/03/16
- Re: [RFC v2 11/13] vhost: Shadow virtqueue buffers forwarding, Eugenio Perez Martin, 2021/03/17
- Re: [RFC v2 11/13] vhost: Shadow virtqueue buffers forwarding, Jason Wang, 2021/03/17
- Re: [RFC v2 11/13] vhost: Shadow virtqueue buffers forwarding, Eugenio Perez Martin, 2021/03/18
- Re: [RFC v2 11/13] vhost: Shadow virtqueue buffers forwarding, Jason Wang, 2021/03/18
- Re: [RFC v2 11/13] vhost: Shadow virtqueue buffers forwarding, Eugenio Perez Martin, 2021/03/18
[RFC v2 13/13] vhost: Use VRING_AVAIL_F_NO_INTERRUPT at device call on shadow virtqueue,
Eugenio Pérez <=
Re: [RFC v2 00/13] vDPA software assisted live migration, Jason Wang, 2021/03/16