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[Qemu-devel] [PULL 10/14] virtio: turn vq->notification into a nested co
From: |
Stefan Hajnoczi |
Subject: |
[Qemu-devel] [PULL 10/14] virtio: turn vq->notification into a nested counter |
Date: |
Wed, 4 Jan 2017 13:34:10 +0000 |
Polling should disable virtqueue notifications but that requires nested
virtio_queue_set_notification() calls. Turn vq->notification into a
counter so it is possible to do nesting.
Signed-off-by: Stefan Hajnoczi <address@hidden>
Reviewed-by: Paolo Bonzini <address@hidden>
Message-id: address@hidden
Signed-off-by: Stefan Hajnoczi <address@hidden>
---
hw/virtio/virtio.c | 18 ++++++++++++------
1 file changed, 12 insertions(+), 6 deletions(-)
diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c
index 3870411..79b5c36 100644
--- a/hw/virtio/virtio.c
+++ b/hw/virtio/virtio.c
@@ -87,8 +87,8 @@ struct VirtQueue
/* Last used index value we have signalled on */
bool signalled_used_valid;
- /* Notification enabled? */
- bool notification;
+ /* Nested host->guest notification disabled counter */
+ unsigned int notification_disabled;
uint16_t queue_index;
@@ -201,7 +201,7 @@ static inline void vring_used_flags_unset_bit(VirtQueue
*vq, int mask)
static inline void vring_set_avail_event(VirtQueue *vq, uint16_t val)
{
hwaddr pa;
- if (!vq->notification) {
+ if (vq->notification_disabled) {
return;
}
pa = vq->vring.used + offsetof(VRingUsed, ring[vq->vring.num]);
@@ -210,7 +210,13 @@ static inline void vring_set_avail_event(VirtQueue *vq,
uint16_t val)
void virtio_queue_set_notification(VirtQueue *vq, int enable)
{
- vq->notification = enable;
+ if (enable) {
+ assert(vq->notification_disabled > 0);
+ vq->notification_disabled--;
+ } else {
+ vq->notification_disabled++;
+ }
+
if (virtio_vdev_has_feature(vq->vdev, VIRTIO_RING_F_EVENT_IDX)) {
vring_set_avail_event(vq, vring_avail_idx(vq));
} else if (enable) {
@@ -959,7 +965,7 @@ void virtio_reset(void *opaque)
virtio_queue_set_vector(vdev, i, VIRTIO_NO_VECTOR);
vdev->vq[i].signalled_used = 0;
vdev->vq[i].signalled_used_valid = false;
- vdev->vq[i].notification = true;
+ vdev->vq[i].notification_disabled = 0;
vdev->vq[i].vring.num = vdev->vq[i].vring.num_default;
vdev->vq[i].inuse = 0;
}
@@ -1770,7 +1776,7 @@ int virtio_load(VirtIODevice *vdev, QEMUFile *f, int
version_id)
vdev->vq[i].vring.desc = qemu_get_be64(f);
qemu_get_be16s(f, &vdev->vq[i].last_avail_idx);
vdev->vq[i].signalled_used_valid = false;
- vdev->vq[i].notification = true;
+ vdev->vq[i].notification_disabled = 0;
if (vdev->vq[i].vring.desc) {
/* XXX virtio-1 devices */
--
2.9.3
- [Qemu-devel] [PULL 00/14] Block patches, Stefan Hajnoczi, 2017/01/04
- [Qemu-devel] [PULL 02/14] aio: add flag to skip fds to aio_dispatch(), Stefan Hajnoczi, 2017/01/04
- [Qemu-devel] [PULL 01/14] HACKING: document #include order, Stefan Hajnoczi, 2017/01/04
- [Qemu-devel] [PULL 04/14] aio: add polling mode to AioContext, Stefan Hajnoczi, 2017/01/04
- [Qemu-devel] [PULL 06/14] linux-aio: poll ring for completions, Stefan Hajnoczi, 2017/01/04
- [Qemu-devel] [PULL 07/14] iothread: add polling parameters, Stefan Hajnoczi, 2017/01/04
- [Qemu-devel] [PULL 05/14] virtio: poll virtqueues for new buffers, Stefan Hajnoczi, 2017/01/04
- [Qemu-devel] [PULL 03/14] aio: add AioPollFn and io_poll() interface, Stefan Hajnoczi, 2017/01/04
- [Qemu-devel] [PULL 08/14] virtio-blk: suppress virtqueue kick during processing, Stefan Hajnoczi, 2017/01/04
- [Qemu-devel] [PULL 09/14] virtio-scsi: suppress virtqueue kick during processing, Stefan Hajnoczi, 2017/01/04
- [Qemu-devel] [PULL 10/14] virtio: turn vq->notification into a nested counter,
Stefan Hajnoczi <=
- [Qemu-devel] [PULL 12/14] virtio: disable virtqueue notifications during polling, Stefan Hajnoczi, 2017/01/04
- [Qemu-devel] [PULL 11/14] aio: add .io_poll_begin/end() callbacks, Stefan Hajnoczi, 2017/01/04
- [Qemu-devel] [PULL 13/14] aio: self-tune polling time, Stefan Hajnoczi, 2017/01/04
- [Qemu-devel] [PULL 14/14] iothread: add poll-grow and poll-shrink parameters, Stefan Hajnoczi, 2017/01/04
- Re: [Qemu-devel] [PULL 00/14] Block patches, Peter Maydell, 2017/01/05