When the guest memory is hotplugged, the vhost application which
enables DMA acceleration must stop DMA transfers before the vhost
re-maps the guest memory.
To accomplish that, we need to do these changes in the vhost sample:
1. add inflight pkt count.
2. add vring_state_changed() callback.
3. add inflight pkt drain process in destroy_device() and
vring_state_changed().
Signed-off-by: Cheng Jiang <cheng1.ji...@intel.com>
---
examples/vhost/main.c | 48 +++++++++++++++++++++++++++++++++++++++++--
examples/vhost/main.h | 1 +
2 files changed, 47 insertions(+), 2 deletions(-)
diff --git a/examples/vhost/main.c b/examples/vhost/main.c
index d2179eadb9..70bb67c7f8 100644
--- a/examples/vhost/main.c
+++ b/examples/vhost/main.c
@@ -851,8 +851,11 @@ complete_async_pkts(struct vhost_dev *vdev)
complete_count = rte_vhost_poll_enqueue_completed(vdev->vid,
VIRTIO_RXQ, p_cpl, MAX_PKT_BURST);
- if (complete_count)
+ if (complete_count) {
free_pkts(p_cpl, complete_count);
+ __atomic_sub_fetch(&vdev->pkts_inflight, complete_count,
__ATOMIC_SEQ_CST);
+ }
+
}
static __rte_always_inline void
@@ -895,6 +898,7 @@ drain_vhost(struct vhost_dev *vdev)
complete_async_pkts(vdev);
ret = rte_vhost_submit_enqueue_burst(vdev->vid, VIRTIO_RXQ,
m, nr_xmit, m_cpu_cpl, &cpu_cpl_nr);
+ __atomic_add_fetch(&vdev->pkts_inflight, ret - cpu_cpl_nr,
__ATOMIC_SEQ_CST);
if (cpu_cpl_nr)
free_pkts(m_cpu_cpl, cpu_cpl_nr);
@@ -1226,6 +1230,9 @@ drain_eth_rx(struct vhost_dev *vdev)
enqueue_count = rte_vhost_submit_enqueue_burst(vdev->vid,
VIRTIO_RXQ, pkts, rx_count,
m_cpu_cpl, &cpu_cpl_nr);
+ __atomic_add_fetch(&vdev->pkts_inflight, enqueue_count -
cpu_cpl_nr,
+ __ATOMIC_SEQ_CST);
+
if (cpu_cpl_nr)
free_pkts(m_cpu_cpl, cpu_cpl_nr);
@@ -1397,8 +1404,15 @@ destroy_device(int vid)
"(%d) device has been removed from data core\n",
vdev->vid);
- if (async_vhost_driver)
+ if (async_vhost_driver) {
+ uint16_t n_pkt = 0;
+ struct rte_mbuf *m_cpl[vdev->pkts_inflight];
+ n_pkt = rte_vhost_drain_queue_thread_unsafe(vid, VIRTIO_RXQ,
m_cpl,
+ vdev->pkts_inflight);
+
+ free_pkts(m_cpl, n_pkt);
rte_vhost_async_channel_unregister(vid, VIRTIO_RXQ);
+ }
rte_free(vdev);
}
@@ -1487,6 +1501,35 @@ new_device(int vid)
return 0;
}
+static int
+vring_state_changed(int vid, uint16_t queue_id, int enable)
+{
+ struct vhost_dev *vdev = NULL;
+
+ TAILQ_FOREACH(vdev, &vhost_dev_list, global_vdev_entry) {
+ if (vdev->vid == vid)
+ break;
+ }
+ if (!vdev)
+ return -1;
+
+ if (queue_id != VIRTIO_RXQ)
+ return 0;
+
+ if (async_vhost_driver) {
+ if (!enable) {
+ uint16_t n_pkt;
+ struct rte_mbuf *m_cpl[vdev->pkts_inflight];
+
+ n_pkt = rte_vhost_drain_queue_thread_unsafe(vid,
queue_id,
+ m_cpl,
vdev->pkts_inflight);
+ free_pkts(m_cpl, n_pkt);
+ }
+ }
+
+ return 0;
+}
+
/*
* These callback allow devices to be added to the data core when configuration
* has been fully complete.
@@ -1495,6 +1538,7 @@ static const struct vhost_device_ops
virtio_net_device_ops =
{
.new_device = new_device,
.destroy_device = destroy_device,
+ .vring_state_changed = vring_state_changed,
};
/*
diff --git a/examples/vhost/main.h b/examples/vhost/main.h
index 0ccdce4b4a..e7b1ac60a6 100644
--- a/examples/vhost/main.h
+++ b/examples/vhost/main.h
@@ -51,6 +51,7 @@ struct vhost_dev {
uint64_t features;
size_t hdr_len;
uint16_t nr_vrings;
+ uint16_t pkts_inflight;
struct rte_vhost_memory *mem;
struct device_statistics stats;
TAILQ_ENTRY(vhost_dev) global_vdev_entry;
--
2.29.2
