Mailing List Archive

This patch supports dgram on vhost side, including
tx and rx. The vhost send packets asynchronously.

Signed-off-by: Jiang Wang <jiang.wang@bytedance.com>
---
drivers/vhost/vsock.c | 199 +++++++++++++++++++++++++++++++++++++++++++-------
1 file changed, 173 insertions(+), 26 deletions(-)

diff --git a/drivers/vhost/vsock.c b/drivers/vhost/vsock.c
index 81d064601093..d366463be6d4 100644
--- a/drivers/vhost/vsock.c
+++ b/drivers/vhost/vsock.c
@@ -28,7 +28,10 @@
* small pkts.
*/
#define VHOST_VSOCK_PKT_WEIGHT 256
+#define VHOST_VSOCK_DGRM_MAX_PENDING_PKT 128

+/* Max wait time in busy poll in microseconds */
+#define VHOST_VSOCK_BUSY_POLL_TIMEOUT 20
enum {
VHOST_VSOCK_FEATURES = VHOST_FEATURES |
(1ULL << VIRTIO_F_ACCESS_PLATFORM) |
@@ -45,7 +48,7 @@ static DEFINE_READ_MOSTLY_HASHTABLE(vhost_vsock_hash, 8);

struct vhost_vsock {
struct vhost_dev dev;
- struct vhost_virtqueue vqs[2];
+ struct vhost_virtqueue vqs[4];

/* Link to global vhost_vsock_hash, writes use vhost_vsock_mutex */
struct hlist_node hash;
@@ -54,6 +57,11 @@ struct vhost_vsock {
spinlock_t send_pkt_list_lock;
struct list_head send_pkt_list; /* host->guest pending packets */

+ spinlock_t dgram_send_pkt_list_lock;
+ struct list_head dgram_send_pkt_list; /* host->guest pending packets */
+ struct vhost_work dgram_send_pkt_work;
+ int dgram_used; /*pending packets to be send */
+
atomic_t queued_replies;

u32 guest_cid;
@@ -90,10 +98,22 @@ static void
vhost_transport_do_send_pkt(struct vhost_vsock *vsock,
struct vhost_virtqueue *vq)
{
- struct vhost_virtqueue *tx_vq = &vsock->vqs[VSOCK_VQ_TX];
+ struct vhost_virtqueue *tx_vq;
int pkts = 0, total_len = 0;
bool added = false;
bool restart_tx = false;
+ spinlock_t *lock;
+ struct list_head *send_pkt_list;
+
+ if (vq == &vsock->vqs[VSOCK_VQ_RX]) {
+ tx_vq = &vsock->vqs[VSOCK_VQ_TX];
+ lock = &vsock->send_pkt_list_lock;
+ send_pkt_list = &vsock->send_pkt_list;
+ } else {
+ tx_vq = &vsock->vqs[VSOCK_VQ_DGRAM_TX];
+ lock = &vsock->dgram_send_pkt_list_lock;
+ send_pkt_list = &vsock->dgram_send_pkt_list;
+ }

mutex_lock(&vq->mutex);

@@ -113,36 +133,48 @@ vhost_transport_do_send_pkt(struct vhost_vsock *vsock,
size_t nbytes;
size_t iov_len, payload_len;
int head;
+ bool is_dgram = false;

- spin_lock_bh(&vsock->send_pkt_list_lock);
- if (list_empty(&vsock->send_pkt_list)) {
- spin_unlock_bh(&vsock->send_pkt_list_lock);
+ spin_lock_bh(lock);
+ if (list_empty(send_pkt_list)) {
+ spin_unlock_bh(lock);
vhost_enable_notify(&vsock->dev, vq);
break;
}

- pkt = list_first_entry(&vsock->send_pkt_list,
+ pkt = list_first_entry(send_pkt_list,
struct virtio_vsock_pkt, list);
list_del_init(&pkt->list);
- spin_unlock_bh(&vsock->send_pkt_list_lock);
+ spin_unlock_bh(lock);
+
+ if (pkt->hdr.type == VIRTIO_VSOCK_TYPE_DGRAM)
+ is_dgram = true;

head = vhost_get_vq_desc(vq, vq->iov, ARRAY_SIZE(vq->iov),
&out, &in, NULL, NULL);
if (head < 0) {
- spin_lock_bh(&vsock->send_pkt_list_lock);
- list_add(&pkt->list, &vsock->send_pkt_list);
- spin_unlock_bh(&vsock->send_pkt_list_lock);
+ spin_lock_bh(lock);
+ list_add(&pkt->list, send_pkt_list);
+ spin_unlock_bh(lock);
break;
}

if (head == vq->num) {
- spin_lock_bh(&vsock->send_pkt_list_lock);
- list_add(&pkt->list, &vsock->send_pkt_list);
- spin_unlock_bh(&vsock->send_pkt_list_lock);
+ if (is_dgram) {
+ virtio_transport_free_pkt(pkt);
+ vq_err(vq, "Dgram virtqueue is full!");
+ spin_lock_bh(lock);
+ vsock->dgram_used--;
+ spin_unlock_bh(lock);
+ break;
+ }
+ spin_lock_bh(lock);
+ list_add(&pkt->list, send_pkt_list);
+ spin_unlock_bh(lock);

/* We cannot finish yet if more buffers snuck in while
- * re-enabling notify.
- */
+ * re-enabling notify.
+ */
if (unlikely(vhost_enable_notify(&vsock->dev, vq))) {
vhost_disable_notify(&vsock->dev, vq);
continue;
@@ -153,6 +185,12 @@ vhost_transport_do_send_pkt(struct vhost_vsock *vsock,
if (out) {
virtio_transport_free_pkt(pkt);
vq_err(vq, "Expected 0 output buffers, got %u\n", out);
+ if (is_dgram) {
+ spin_lock_bh(lock);
+ vsock->dgram_used--;
+ spin_unlock_bh(lock);
+ }
+
break;
}

@@ -160,6 +198,18 @@ vhost_transport_do_send_pkt(struct vhost_vsock *vsock,
if (iov_len < sizeof(pkt->hdr)) {
virtio_transport_free_pkt(pkt);
vq_err(vq, "Buffer len [%zu] too small\n", iov_len);
+ if (is_dgram) {
+ spin_lock_bh(lock);
+ vsock->dgram_used--;
+ spin_unlock_bh(lock);
+ }
+ break;
+ }
+
+ if (iov_len < pkt->len - pkt->off &&
+ vq == &vsock->vqs[VSOCK_VQ_DGRAM_RX]) {
+ virtio_transport_free_pkt(pkt);
+ vq_err(vq, "Buffer len [%zu] too small for dgram\n", iov_len);
break;
}

@@ -179,6 +229,11 @@ vhost_transport_do_send_pkt(struct vhost_vsock *vsock,
if (nbytes != sizeof(pkt->hdr)) {
virtio_transport_free_pkt(pkt);
vq_err(vq, "Faulted on copying pkt hdr\n");
+ if (is_dgram) {
+ spin_lock_bh(lock);
+ vsock->dgram_used--;
+ spin_unlock_bh(lock);
+ }
break;
}

@@ -204,16 +259,17 @@ vhost_transport_do_send_pkt(struct vhost_vsock *vsock,
/* If we didn't send all the payload we can requeue the packet
* to send it with the next available buffer.
*/
- if (pkt->off < pkt->len) {
+ if ((pkt->off < pkt->len)
+ && (vq == &vsock->vqs[VSOCK_VQ_RX])) {
/* We are queueing the same virtio_vsock_pkt to handle
* the remaining bytes, and we want to deliver it
* to monitoring devices in the next iteration.
*/
pkt->tap_delivered = false;

- spin_lock_bh(&vsock->send_pkt_list_lock);
- list_add(&pkt->list, &vsock->send_pkt_list);
- spin_unlock_bh(&vsock->send_pkt_list_lock);
+ spin_lock_bh(lock);
+ list_add(&pkt->list, send_pkt_list);
+ spin_unlock_bh(lock);
} else {
if (pkt->reply) {
int val;
@@ -228,6 +284,11 @@ vhost_transport_do_send_pkt(struct vhost_vsock *vsock,
}

virtio_transport_free_pkt(pkt);
+ if (is_dgram) {
+ spin_lock_bh(lock);
+ vsock->dgram_used--;
+ spin_unlock_bh(lock);
+ }
}
} while(likely(!vhost_exceeds_weight(vq, ++pkts, total_len)));
if (added)
@@ -251,11 +312,25 @@ static void vhost_transport_send_pkt_work(struct vhost_work *work)
vhost_transport_do_send_pkt(vsock, vq);
}

+static void vhost_transport_dgram_send_pkt_work(struct vhost_work *work)
+{
+ struct vhost_virtqueue *vq;
+ struct vhost_vsock *vsock;
+
+ vsock = container_of(work, struct vhost_vsock, dgram_send_pkt_work);
+ vq = &vsock->vqs[VSOCK_VQ_DGRAM_RX];
+
+ vhost_transport_do_send_pkt(vsock, vq);
+}
+
static int
vhost_transport_send_pkt(struct virtio_vsock_pkt *pkt)
{
struct vhost_vsock *vsock;
int len = pkt->len;
+ spinlock_t *lock;
+ struct list_head *send_pkt_list;
+ struct vhost_work *work;

rcu_read_lock();

@@ -267,14 +342,38 @@ vhost_transport_send_pkt(struct virtio_vsock_pkt *pkt)
return -ENODEV;
}

+ if (pkt->hdr.type == VIRTIO_VSOCK_TYPE_STREAM) {
+ lock = &vsock->send_pkt_list_lock;
+ send_pkt_list = &vsock->send_pkt_list;
+ work = &vsock->send_pkt_work;
+ } else if (pkt->hdr.type == VIRTIO_VSOCK_TYPE_DGRAM) {
+ lock = &vsock->dgram_send_pkt_list_lock;
+ send_pkt_list = &vsock->dgram_send_pkt_list;
+ work = &vsock->dgram_send_pkt_work;
+ } else {
+ rcu_read_unlock();
+ virtio_transport_free_pkt(pkt);
+ return -EINVAL;
+ }
+
+
if (pkt->reply)
atomic_inc(&vsock->queued_replies);

- spin_lock_bh(&vsock->send_pkt_list_lock);
- list_add_tail(&pkt->list, &vsock->send_pkt_list);
- spin_unlock_bh(&vsock->send_pkt_list_lock);
+ spin_lock_bh(lock);
+ if (pkt->hdr.type == VIRTIO_VSOCK_TYPE_DGRAM) {
+ if (vsock->dgram_used == VHOST_VSOCK_DGRM_MAX_PENDING_PKT)
+ len = -ENOMEM;
+ else {
+ vsock->dgram_used++;
+ list_add_tail(&pkt->list, send_pkt_list);
+ }
+ } else
+ list_add_tail(&pkt->list, send_pkt_list);

- vhost_work_queue(&vsock->dev, &vsock->send_pkt_work);
+ spin_unlock_bh(lock);
+
+ vhost_work_queue(&vsock->dev, work);

rcu_read_unlock();
return len;
@@ -355,7 +454,8 @@ vhost_vsock_alloc_pkt(struct vhost_virtqueue *vq,
return NULL;
}

- if (le16_to_cpu(pkt->hdr.type) == VIRTIO_VSOCK_TYPE_STREAM)
+ if (le16_to_cpu(pkt->hdr.type) == VIRTIO_VSOCK_TYPE_STREAM
+ || le16_to_cpu(pkt->hdr.type) == VIRTIO_VSOCK_TYPE_DGRAM)
pkt->len = le32_to_cpu(pkt->hdr.len);

/* No payload */
@@ -442,6 +542,18 @@ static struct virtio_transport vhost_transport = {
.send_pkt = vhost_transport_send_pkt,
};

+static inline unsigned long busy_clock(void)
+{
+ return local_clock() >> 10;
+}
+
+static bool vhost_can_busy_poll(unsigned long endtime)
+{
+ return likely(!need_resched() && !time_after(busy_clock(), endtime) &&
+ !signal_pending(current));
+}
+
+
static void vhost_vsock_handle_tx_kick(struct vhost_work *work)
{
struct vhost_virtqueue *vq = container_of(work, struct vhost_virtqueue,
@@ -452,6 +564,8 @@ static void vhost_vsock_handle_tx_kick(struct vhost_work *work)
int head, pkts = 0, total_len = 0;
unsigned int out, in;
bool added = false;
+ unsigned long busyloop_timeout = VHOST_VSOCK_BUSY_POLL_TIMEOUT;
+ unsigned long endtime;

mutex_lock(&vq->mutex);

@@ -461,11 +575,14 @@ static void vhost_vsock_handle_tx_kick(struct vhost_work *work)
if (!vq_meta_prefetch(vq))
goto out;

+ endtime = busy_clock() + busyloop_timeout;
vhost_disable_notify(&vsock->dev, vq);
+ preempt_disable();
do {
u32 len;

- if (!vhost_vsock_more_replies(vsock)) {
+ if (vq == &vsock->vqs[VSOCK_VQ_TX]
+ && !vhost_vsock_more_replies(vsock)) {
/* Stop tx until the device processes already
* pending replies. Leave tx virtqueue
* callbacks disabled.
@@ -479,6 +596,11 @@ static void vhost_vsock_handle_tx_kick(struct vhost_work *work)
break;

if (head == vq->num) {
+ if (vhost_can_busy_poll(endtime)) {
+ cpu_relax();
+ continue;
+ }
+
if (unlikely(vhost_enable_notify(&vsock->dev, vq))) {
vhost_disable_notify(&vsock->dev, vq);
continue;
@@ -510,6 +632,7 @@ static void vhost_vsock_handle_tx_kick(struct vhost_work *work)
total_len += len;
added = true;
} while(likely(!vhost_exceeds_weight(vq, ++pkts, total_len)));
+ preempt_enable();

no_more_replies:
if (added)
@@ -565,6 +688,7 @@ static int vhost_vsock_start(struct vhost_vsock *vsock)
* let's kick the send worker to send them.
*/
vhost_work_queue(&vsock->dev, &vsock->send_pkt_work);
+ vhost_work_queue(&vsock->dev, &vsock->dgram_send_pkt_work);

mutex_unlock(&vsock->dev.mutex);
return 0;
@@ -639,8 +763,14 @@ static int vhost_vsock_dev_open(struct inode *inode, struct file *file)

vqs[VSOCK_VQ_TX] = &vsock->vqs[VSOCK_VQ_TX];
vqs[VSOCK_VQ_RX] = &vsock->vqs[VSOCK_VQ_RX];
+ vqs[VSOCK_VQ_DGRAM_TX] = &vsock->vqs[VSOCK_VQ_DGRAM_TX];
+ vqs[VSOCK_VQ_DGRAM_RX] = &vsock->vqs[VSOCK_VQ_DGRAM_RX];
vsock->vqs[VSOCK_VQ_TX].handle_kick = vhost_vsock_handle_tx_kick;
vsock->vqs[VSOCK_VQ_RX].handle_kick = vhost_vsock_handle_rx_kick;
+ vsock->vqs[VSOCK_VQ_DGRAM_TX].handle_kick =
+ vhost_vsock_handle_tx_kick;
+ vsock->vqs[VSOCK_VQ_DGRAM_RX].handle_kick =
+ vhost_vsock_handle_rx_kick;

vhost_dev_init(&vsock->dev, vqs, ARRAY_SIZE(vsock->vqs),
UIO_MAXIOV, VHOST_VSOCK_PKT_WEIGHT,
@@ -650,6 +780,11 @@ static int vhost_vsock_dev_open(struct inode *inode, struct file *file)
spin_lock_init(&vsock->send_pkt_list_lock);
INIT_LIST_HEAD(&vsock->send_pkt_list);
vhost_work_init(&vsock->send_pkt_work, vhost_transport_send_pkt_work);
+ spin_lock_init(&vsock->dgram_send_pkt_list_lock);
+ INIT_LIST_HEAD(&vsock->dgram_send_pkt_list);
+ vhost_work_init(&vsock->dgram_send_pkt_work,
+ vhost_transport_dgram_send_pkt_work);
+
return 0;

out:
@@ -665,6 +800,7 @@ static void vhost_vsock_flush(struct vhost_vsock *vsock)
if (vsock->vqs[i].handle_kick)
vhost_poll_flush(&vsock->vqs[i].poll);
vhost_work_flush(&vsock->dev, &vsock->send_pkt_work);
+ vhost_work_flush(&vsock->dev, &vsock->dgram_send_pkt_work);
}

static void vhost_vsock_reset_orphans(struct sock *sk)
@@ -724,6 +860,17 @@ static int vhost_vsock_dev_release(struct inode *inode, struct file *file)
}
spin_unlock_bh(&vsock->send_pkt_list_lock);

+ spin_lock_bh(&vsock->dgram_send_pkt_list_lock);
+ while (!list_empty(&vsock->dgram_send_pkt_list)) {
+ struct virtio_vsock_pkt *pkt;
+
+ pkt = list_first_entry(&vsock->dgram_send_pkt_list,
+ struct virtio_vsock_pkt, list);
+ list_del_init(&pkt->list);
+ virtio_transport_free_pkt(pkt);
+ }
+ spin_unlock_bh(&vsock->dgram_send_pkt_list_lock);
+
vhost_dev_cleanup(&vsock->dev);
kfree(vsock->dev.vqs);
vhost_vsock_free(vsock);
@@ -906,7 +1053,7 @@ static int __init vhost_vsock_init(void)
int ret;

ret = vsock_core_register(&vhost_transport.transport,
- VSOCK_TRANSPORT_F_H2G);
+ VSOCK_TRANSPORT_F_H2G | VSOCK_TRANSPORT_F_DGRAM);
if (ret < 0)
return ret;
return misc_register(&vhost_vsock_misc);
--
2.11.0