From: Asias He <asias@xxxxxxxxxx>
VM sockets virtio transport implementation. This driver runs in the
guest.
Signed-off-by: Asias He <asias@xxxxxxxxxx>
Signed-off-by: Stefan Hajnoczi <stefanha@xxxxxxxxxx>
---
v6:
* Start/stop rx depending on reply packet accounting to bound memory
allocation if the host is not processing rx packets
* 64-bit CID in packet header to match virtio-vsock specification
* Use send_pkt_list to defer transmission
* Avoid leaking virtqueue buffers and pkt lists on shutdown
* Remove total_tx_buf accounting, it is ineffective because control
packets are not included
v5:
* Add transport reset event handling
* Drop ctrl virtqueue
v4:
* Add MAINTAINERS file entry
* Drop short/long rx packets
* checkpatch.pl cleanups
* Clarify locking in struct virtio_vsock
* Narrow local variable scopes as suggested by Alex Bennee
* Call wake_up() after decrementing total_tx_buf to avoid deadlock
v2:
* Fix total_tx_buf accounting
* Add virtio_transport global mutex to prevent races
---
MAINTAINERS | 1 +
net/vmw_vsock/virtio_transport.c | 624 +++++++++++++++++++++++++++++++++++++++
2 files changed, 625 insertions(+)
create mode 100644 net/vmw_vsock/virtio_transport.c
diff --git a/MAINTAINERS b/MAINTAINERS
index b49ffb8..7302663 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -12147,6 +12147,7 @@ S: Maintained
F: include/linux/virtio_vsock.h
F: include/uapi/linux/virtio_vsock.h
F: net/vmw_vsock/virtio_transport_common.c
+F: net/vmw_vsock/virtio_transport.c
VIRTUAL SERIO DEVICE DRIVER
M: Stephen Chandler Paul <thatslyude@xxxxxxxxx>
diff --git a/net/vmw_vsock/virtio_transport.c b/net/vmw_vsock/virtio_transport.c
new file mode 100644
index 0000000..699dfab
--- /dev/null
+++ b/net/vmw_vsock/virtio_transport.c
@@ -0,0 +1,624 @@
+/*
+ * virtio transport for vsock
+ *
+ * Copyright (C) 2013-2015 Red Hat, Inc.
+ * Author: Asias He <asias@xxxxxxxxxx>
+ * Stefan Hajnoczi <stefanha@xxxxxxxxxx>
+ *
+ * Some of the code is take from Gerd Hoffmann <kraxel@xxxxxxxxxx>'s
+ * early virtio-vsock proof-of-concept bits.
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2.
+ */
+#include <linux/spinlock.h>
+#include <linux/module.h>
+#include <linux/list.h>
+#include <linux/atomic.h>
+#include <linux/virtio.h>
+#include <linux/virtio_ids.h>
+#include <linux/virtio_config.h>
+#include <linux/virtio_vsock.h>
+#include <net/sock.h>
+#include <linux/mutex.h>
+#include <net/af_vsock.h>
+
+static struct workqueue_struct *virtio_vsock_workqueue;
+static struct virtio_vsock *the_virtio_vsock;
+static DEFINE_MUTEX(the_virtio_vsock_mutex); /* protects the_virtio_vsock */
+
+struct virtio_vsock {
+ struct virtio_device *vdev;
+ struct virtqueue *vqs[VSOCK_VQ_MAX];
+
+ /* Virtqueue processing is deferred to a workqueue */
+ struct work_struct tx_work;
+ struct work_struct rx_work;
+ struct work_struct event_work;
+
+ /* The following fields are protected by tx_lock. vqs[VSOCK_VQ_TX]
+ * must be accessed with tx_lock held.
+ */
+ struct mutex tx_lock;
+
+ struct work_struct send_pkt_work;
+ spinlock_t send_pkt_list_lock;
+ struct list_head send_pkt_list;
+
+ atomic_t queued_replies;
+
+ /* The following fields are protected by rx_lock. vqs[VSOCK_VQ_RX]
+ * must be accessed with rx_lock held.
+ */
+ struct mutex rx_lock;
+ int rx_buf_nr;
+ int rx_buf_max_nr;
+
+ /* The following fields are protected by event_lock.
+ * vqs[VSOCK_VQ_EVENT] must be accessed with event_lock held.
+ */
+ struct mutex event_lock;
+ struct virtio_vsock_event event_list[8];
+
+ u32 guest_cid;
+};
+
+static struct virtio_vsock *virtio_vsock_get(void)
+{
+ return the_virtio_vsock;
+}
+
+static u32 virtio_transport_get_local_cid(void)
+{
+ struct virtio_vsock *vsock = virtio_vsock_get();
+
+ return vsock->guest_cid;
+}
+
+static void
+virtio_transport_send_pkt_work(struct work_struct *work)
+{
+ struct virtio_vsock *vsock =
+ container_of(work, struct virtio_vsock, send_pkt_work);
+ struct virtqueue *vq;
+ bool added = false;
+ bool restart_rx = false;
+
+ mutex_lock(&vsock->tx_lock);
+
+ vq = vsock->vqs[VSOCK_VQ_TX];
+
+ /* Avoid unnecessary interrupts while we're processing the ring */
+ virtqueue_disable_cb(vq);
+
+ for (;;) {
+ struct virtio_vsock_pkt *pkt;
+ struct scatterlist hdr, buf, *sgs[2];
+ int ret, in_sg = 0, out_sg = 0;
+ bool reply;
+
+ spin_lock_bh(&vsock->send_pkt_list_lock);
+ if (list_empty(&vsock->send_pkt_list)) {
+ spin_unlock_bh(&vsock->send_pkt_list_lock);
+ virtqueue_enable_cb(vq);
+ break;
+ }
+
+ pkt = list_first_entry(&vsock->send_pkt_list,
+ struct virtio_vsock_pkt, list);
+ list_del_init(&pkt->list);
+ spin_unlock_bh(&vsock->send_pkt_list_lock);
+
+ reply = pkt->reply;
+
+ sg_init_one(&hdr, &pkt->hdr, sizeof(pkt->hdr));
+ sgs[out_sg++] = &hdr;
+ if (pkt->buf) {
+ sg_init_one(&buf, pkt->buf, pkt->len);
+ sgs[out_sg++] = &buf;
+ }
+
+ ret = virtqueue_add_sgs(vq, sgs, out_sg, in_sg, pkt, GFP_KERNEL);
+ if (ret < 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);
+
+ if (!virtqueue_enable_cb(vq) && ret == -ENOSPC)
+ continue; /* retry now that we have more space */
+ break;
+ }
+
+ if (reply) {
+ struct virtqueue *rx_vq = vsock->vqs[VSOCK_VQ_RX];
+ int val;
+
+ val = atomic_dec_return(&vsock->queued_replies);
+
+ /* Do we now have resources to resume rx processing? */
+ if (val + 1 == virtqueue_get_vring_size(rx_vq))
+ restart_rx = true;
+ }
+
+ added = true;
+ }
+
+ if (added)
+ virtqueue_kick(vq);
+
+ mutex_unlock(&vsock->tx_lock);
+
+ if (restart_rx)
+ queue_work(virtio_vsock_workqueue, &vsock->rx_work);
+}
+
+static int
+virtio_transport_send_pkt(struct virtio_vsock_pkt *pkt)
+{
+ struct virtio_vsock *vsock;
+ int len = pkt->len;
+
+ vsock = virtio_vsock_get();
+ if (!vsock) {
+ virtio_transport_free_pkt(pkt);
+ return -ENODEV;
+ }
+
+ 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);
+
+ queue_work(virtio_vsock_workqueue, &vsock->send_pkt_work);
+ return len;
+}
+
+static void virtio_vsock_rx_fill(struct virtio_vsock *vsock)
+{
+ int buf_len = VIRTIO_VSOCK_DEFAULT_RX_BUF_SIZE;
+ struct virtio_vsock_pkt *pkt;
+ struct scatterlist hdr, buf, *sgs[2];
+ struct virtqueue *vq;
+ int ret;
+
+ vq = vsock->vqs[VSOCK_VQ_RX];
+
+ do {
+ pkt = kzalloc(sizeof(*pkt), GFP_KERNEL);
+ if (!pkt)
+ break;
+
+ pkt->buf = kmalloc(buf_len, GFP_KERNEL);
+ if (!pkt->buf) {
+ virtio_transport_free_pkt(pkt);
+ break;
+ }
+
+ pkt->len = buf_len;
+
+ sg_init_one(&hdr, &pkt->hdr, sizeof(pkt->hdr));
+ sgs[0] = &hdr;
+
+ sg_init_one(&buf, pkt->buf, buf_len);
+ sgs[1] = &buf;
+ ret = virtqueue_add_sgs(vq, sgs, 0, 2, pkt, GFP_KERNEL);
+ if (ret) {
+ virtio_transport_free_pkt(pkt);
+ break;
+ }
+ vsock->rx_buf_nr++;
+ } while (vq->num_free);
+ if (vsock->rx_buf_nr > vsock->rx_buf_max_nr)
+ vsock->rx_buf_max_nr = vsock->rx_buf_nr;
+ virtqueue_kick(vq);
+}
+
+static void virtio_transport_tx_work(struct work_struct *work)
+{
+ struct virtio_vsock *vsock =
+ container_of(work, struct virtio_vsock, tx_work);
+ struct virtqueue *vq;
+ bool added = false;
+
+ vq = vsock->vqs[VSOCK_VQ_TX];
+ mutex_lock(&vsock->tx_lock);
+ do {
+ struct virtio_vsock_pkt *pkt;
+ unsigned int len;
+
+ virtqueue_disable_cb(vq);
+ while ((pkt = virtqueue_get_buf(vq, &len)) != NULL) {
+ virtio_transport_free_pkt(pkt);
+ added = true;
+ }
+ } while (!virtqueue_enable_cb(vq));
+ mutex_unlock(&vsock->tx_lock);
+
+ if (added)
+ queue_work(virtio_vsock_workqueue, &vsock->send_pkt_work);
+}
+
+/* Is there space left for replies to rx packets? */
+static bool virtio_transport_more_replies(struct virtio_vsock *vsock)
+{
+ struct virtqueue *vq = vsock->vqs[VSOCK_VQ_RX];
+ int val;
+
+ smp_rmb(); /* paired with atomic_inc() and atomic_dec_return() */
+ val = atomic_read(&vsock->queued_replies);
+
+ return val < virtqueue_get_vring_size(vq);
+}
+
+static void virtio_transport_rx_work(struct work_struct *work)
+{
+ struct virtio_vsock *vsock =
+ container_of(work, struct virtio_vsock, rx_work);
+ struct virtqueue *vq;
+
+ vq = vsock->vqs[VSOCK_VQ_RX];
+
+ mutex_lock(&vsock->rx_lock);
+
+ do {
+ virtqueue_disable_cb(vq);
+ for (;;) {
+ struct virtio_vsock_pkt *pkt;
+ unsigned int len;
+
+ if (!virtio_transport_more_replies(vsock)) {
+ /* Stop rx until the device processes already
+ * pending replies. Leave rx virtqueue
+ * callbacks disabled.
+ */
+ goto out;
+ }
+
+ pkt = virtqueue_get_buf(vq, &len);
+ if (!pkt) {
+ break;
+ }
+
+ vsock->rx_buf_nr--;
+
+ /* Drop short/long packets */
+ if (unlikely(len < sizeof(pkt->hdr) ||
+ len > sizeof(pkt->hdr) + pkt->len)) {
+ virtio_transport_free_pkt(pkt);
+ continue;
+ }
+
+ pkt->len = len - sizeof(pkt->hdr);
+ virtio_transport_recv_pkt(pkt);
+ }
+ } while (!virtqueue_enable_cb(vq));
+
+out:
+ if (vsock->rx_buf_nr < vsock->rx_buf_max_nr / 2)
+ virtio_vsock_rx_fill(vsock);
+ mutex_unlock(&vsock->rx_lock);
+}
+
+/* event_lock must be held */
+static int virtio_vsock_event_fill_one(struct virtio_vsock *vsock,
+ struct virtio_vsock_event *event)
+{
+ struct scatterlist sg;
+ struct virtqueue *vq;
+
+ vq = vsock->vqs[VSOCK_VQ_EVENT];
+
+ sg_init_one(&sg, event, sizeof(*event));
+
+ return virtqueue_add_inbuf(vq, &sg, 1, event, GFP_KERNEL);
+}
+
+/* event_lock must be held */
+static void virtio_vsock_event_fill(struct virtio_vsock *vsock)
+{
+ size_t i;
+
+ for (i = 0; i < ARRAY_SIZE(vsock->event_list); i++) {
+ struct virtio_vsock_event *event = &vsock->event_list[i];
+
+ virtio_vsock_event_fill_one(vsock, event);
+ }
+
+ virtqueue_kick(vsock->vqs[VSOCK_VQ_EVENT]);
+}
+
+static void virtio_vsock_reset_sock(struct sock *sk)
+{
+ lock_sock(sk);
+ sk->sk_state = SS_UNCONNECTED;
+ sk->sk_err = ECONNRESET;
+ sk->sk_error_report(sk);
+ release_sock(sk);
+}
+
+static void virtio_vsock_update_guest_cid(struct virtio_vsock *vsock)
+{
+ struct virtio_device *vdev = vsock->vdev;
+ u64 guest_cid;
+
+ vdev->config->get(vdev, offsetof(struct virtio_vsock_config, guest_cid),
+ &guest_cid, sizeof(guest_cid));
+ vsock->guest_cid = le64_to_cpu(guest_cid);
+}
+
+/* event_lock must be held */
+static void virtio_vsock_event_handle(struct virtio_vsock *vsock,
+ struct virtio_vsock_event *event)
+{
+ switch (le32_to_cpu(event->id)) {
+ case VIRTIO_VSOCK_EVENT_TRANSPORT_RESET:
+ virtio_vsock_update_guest_cid(vsock);
+ vsock_for_each_connected_socket(virtio_vsock_reset_sock);
+ break;
+ }
+}
+
+static void virtio_transport_event_work(struct work_struct *work)
+{
+ struct virtio_vsock *vsock =
+ container_of(work, struct virtio_vsock, event_work);
+ struct virtqueue *vq;
+
+ vq = vsock->vqs[VSOCK_VQ_EVENT];
+
+ mutex_lock(&vsock->event_lock);
+
+ do {
+ struct virtio_vsock_event *event;
+ unsigned int len;
+
+ virtqueue_disable_cb(vq);
+ while ((event = virtqueue_get_buf(vq, &len)) != NULL) {
+ if (len == sizeof(*event))
+ virtio_vsock_event_handle(vsock, event);
+
+ virtio_vsock_event_fill_one(vsock, event);
+ }
+ } while (!virtqueue_enable_cb(vq));
+
+ virtqueue_kick(vsock->vqs[VSOCK_VQ_EVENT]);
+
+ mutex_unlock(&vsock->event_lock);
+}
+
+static void virtio_vsock_event_done(struct virtqueue *vq)
+{
+ struct virtio_vsock *vsock = vq->vdev->priv;
+
+ if (!vsock)
+ return;
+ queue_work(virtio_vsock_workqueue, &vsock->event_work);
+}
+
+static void virtio_vsock_tx_done(struct virtqueue *vq)
+{
+ struct virtio_vsock *vsock = vq->vdev->priv;
+
+ if (!vsock)
+ return;
+ queue_work(virtio_vsock_workqueue, &vsock->tx_work);
+}
+
+static void virtio_vsock_rx_done(struct virtqueue *vq)
+{
+ struct virtio_vsock *vsock = vq->vdev->priv;
+
+ if (!vsock)
+ return;
+ queue_work(virtio_vsock_workqueue, &vsock->rx_work);
+}
+
+static struct virtio_transport virtio_transport = {
+ .transport = {
+ .get_local_cid = virtio_transport_get_local_cid,
+
+ .init = virtio_transport_do_socket_init,
+ .destruct = virtio_transport_destruct,
+ .release = virtio_transport_release,
+ .connect = virtio_transport_connect,
+ .shutdown = virtio_transport_shutdown,
+
+ .dgram_bind = virtio_transport_dgram_bind,
+ .dgram_dequeue = virtio_transport_dgram_dequeue,
+ .dgram_enqueue = virtio_transport_dgram_enqueue,
+ .dgram_allow = virtio_transport_dgram_allow,
+
+ .stream_dequeue = virtio_transport_stream_dequeue,
+ .stream_enqueue = virtio_transport_stream_enqueue,
+ .stream_has_data = virtio_transport_stream_has_data,
+ .stream_has_space = virtio_transport_stream_has_space,
+ .stream_rcvhiwat = virtio_transport_stream_rcvhiwat,
+ .stream_is_active = virtio_transport_stream_is_active,
+ .stream_allow = virtio_transport_stream_allow,
+
+ .notify_poll_in = virtio_transport_notify_poll_in,
+ .notify_poll_out = virtio_transport_notify_poll_out,
+ .notify_recv_init = virtio_transport_notify_recv_init,
+ .notify_recv_pre_block = virtio_transport_notify_recv_pre_block,
+ .notify_recv_pre_dequeue = virtio_transport_notify_recv_pre_dequeue,
+ .notify_recv_post_dequeue = virtio_transport_notify_recv_post_dequeue,
+ .notify_send_init = virtio_transport_notify_send_init,
+ .notify_send_pre_block = virtio_transport_notify_send_pre_block,
+ .notify_send_pre_enqueue = virtio_transport_notify_send_pre_enqueue,
+ .notify_send_post_enqueue = virtio_transport_notify_send_post_enqueue,
+
+ .set_buffer_size = virtio_transport_set_buffer_size,
+ .set_min_buffer_size = virtio_transport_set_min_buffer_size,
+ .set_max_buffer_size = virtio_transport_set_max_buffer_size,
+ .get_buffer_size = virtio_transport_get_buffer_size,
+ .get_min_buffer_size = virtio_transport_get_min_buffer_size,
+ .get_max_buffer_size = virtio_transport_get_max_buffer_size,
+ },
+
+ .send_pkt = virtio_transport_send_pkt,
+};
+
+static int virtio_vsock_probe(struct virtio_device *vdev)
+{
+ vq_callback_t *callbacks[] = {
+ virtio_vsock_rx_done,
+ virtio_vsock_tx_done,
+ virtio_vsock_event_done,
+ };
+ static const char * const names[] = {
+ "rx",
+ "tx",
+ "event",
+ };
+ struct virtio_vsock *vsock = NULL;
+ int ret;
+
+ ret = mutex_lock_interruptible(&the_virtio_vsock_mutex);
+ if (ret)
+ return ret;
+
+ /* Only one virtio-vsock device per guest is supported */
+ if (the_virtio_vsock) {
+ ret = -EBUSY;
+ goto out;
+ }
+
+ vsock = kzalloc(sizeof(*vsock), GFP_KERNEL);
+ if (!vsock) {
+ ret = -ENOMEM;
+ goto out;
+ }
+
+ vsock->vdev = vdev;
+
+ ret = vsock->vdev->config->find_vqs(vsock->vdev, VSOCK_VQ_MAX,
+ vsock->vqs, callbacks, names);
+ if (ret < 0)
+ goto out;
+
+ virtio_vsock_update_guest_cid(vsock);
+
+ ret = vsock_core_init(&virtio_transport.transport);
+ if (ret < 0)
+ goto out_vqs;
+
+ vsock->rx_buf_nr = 0;
+ vsock->rx_buf_max_nr = 0;
+ atomic_set(&vsock->queued_replies, 0);
+
+ vdev->priv = vsock;
+ the_virtio_vsock = vsock;
+ mutex_init(&vsock->tx_lock);
+ mutex_init(&vsock->rx_lock);
+ mutex_init(&vsock->event_lock);
+ spin_lock_init(&vsock->send_pkt_list_lock);
+ INIT_LIST_HEAD(&vsock->send_pkt_list);
+ INIT_WORK(&vsock->rx_work, virtio_transport_rx_work);
+ INIT_WORK(&vsock->tx_work, virtio_transport_tx_work);
+ INIT_WORK(&vsock->event_work, virtio_transport_event_work);
+ INIT_WORK(&vsock->send_pkt_work, virtio_transport_send_pkt_work);
+
+ mutex_lock(&vsock->rx_lock);
+ virtio_vsock_rx_fill(vsock);
+ mutex_unlock(&vsock->rx_lock);
+
+ mutex_lock(&vsock->event_lock);
+ virtio_vsock_event_fill(vsock);
+ mutex_unlock(&vsock->event_lock);
+
+ mutex_unlock(&the_virtio_vsock_mutex);
+ return 0;
+
+out_vqs:
+ vsock->vdev->config->del_vqs(vsock->vdev);
+out:
+ kfree(vsock);
+ mutex_unlock(&the_virtio_vsock_mutex);
+ return ret;
+}
+
+static void virtio_vsock_remove(struct virtio_device *vdev)
+{
+ struct virtio_vsock *vsock = vdev->priv;
+ struct virtio_vsock_pkt *pkt;
+
+ flush_work(&vsock->rx_work);
+ flush_work(&vsock->tx_work);
+ flush_work(&vsock->event_work);
+ flush_work(&vsock->send_pkt_work);
+
+ vdev->config->reset(vdev);
+
+ mutex_lock(&vsock->rx_lock);
+ while ((pkt = virtqueue_detach_unused_buf(vsock->vqs[VSOCK_VQ_RX])))
+ virtio_transport_free_pkt(pkt);
+ mutex_unlock(&vsock->rx_lock);
+
+ mutex_lock(&vsock->tx_lock);
+ while ((pkt = virtqueue_detach_unused_buf(vsock->vqs[VSOCK_VQ_TX])))
+ virtio_transport_free_pkt(pkt);
+ mutex_unlock(&vsock->tx_lock);
+
+ spin_lock_bh(&vsock->send_pkt_list_lock);
+ while (!list_empty(&vsock->send_pkt_list)) {
+ pkt = list_first_entry(&vsock->send_pkt_list,
+ struct virtio_vsock_pkt, list);
+ list_del(&pkt->list);
+ virtio_transport_free_pkt(pkt);
+ }
+ spin_unlock_bh(&vsock->send_pkt_list_lock);
+
+ mutex_lock(&the_virtio_vsock_mutex);
+ the_virtio_vsock = NULL;
+ vsock_core_exit();
+ mutex_unlock(&the_virtio_vsock_mutex);
+
+ vdev->config->del_vqs(vdev);
+
+ kfree(vsock);
+}
+
+static struct virtio_device_id id_table[] = {
+ { VIRTIO_ID_VSOCK, VIRTIO_DEV_ANY_ID },
+ { 0 },
+};
+
+static unsigned int features[] = {
+};
+
+static struct virtio_driver virtio_vsock_driver = {
+ .feature_table = features,
+ .feature_table_size = ARRAY_SIZE(features),
+ .driver.name = KBUILD_MODNAME,
+ .driver.owner = THIS_MODULE,
+ .id_table = id_table,
+ .probe = virtio_vsock_probe,
+ .remove = virtio_vsock_remove,
+};
+
+static int __init virtio_vsock_init(void)
+{
+ int ret;
+
+ virtio_vsock_workqueue = alloc_workqueue("virtio_vsock", 0, 0);
+ if (!virtio_vsock_workqueue)
+ return -ENOMEM;
+ ret = register_virtio_driver(&virtio_vsock_driver);
+ if (ret)
+ destroy_workqueue(virtio_vsock_workqueue);
+ return ret;
+}
+
+static void __exit virtio_vsock_exit(void)
+{
+ unregister_virtio_driver(&virtio_vsock_driver);
+ destroy_workqueue(virtio_vsock_workqueue);
+}
+
+module_init(virtio_vsock_init);
+module_exit(virtio_vsock_exit);
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Asias He");
+MODULE_DESCRIPTION("virtio transport for vsock");
+MODULE_DEVICE_TABLE(virtio, id_table);
--
2.7.4
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