[PATCH v3 2/4] VSOCK: Introduce virtio-vsock.ko
Stefan Hajnoczi
stefanha at redhat.com
Wed Dec 9 12:03:51 UTC 2015
From: Asias He <asias at redhat.com>
VM sockets virtio transport implementation. This module runs in guest
kernel.
Signed-off-by: Asias He <asias at redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha at redhat.com>
---
v2:
* Fix total_tx_buf accounting
* Add virtio_transport global mutex to prevent races
---
net/vmw_vsock/virtio_transport.c | 466 +++++++++++++++++++++++++++++++++++++++
1 file changed, 466 insertions(+)
create mode 100644 net/vmw_vsock/virtio_transport.c
diff --git a/net/vmw_vsock/virtio_transport.c b/net/vmw_vsock/virtio_transport.c
new file mode 100644
index 0000000..df65dca
--- /dev/null
+++ b/net/vmw_vsock/virtio_transport.c
@@ -0,0 +1,466 @@
+/*
+ * virtio transport for vsock
+ *
+ * Copyright (C) 2013-2015 Red Hat, Inc.
+ * Author: Asias He <asias at redhat.com>
+ * Stefan Hajnoczi <stefanha at redhat.com>
+ *
+ * Some of the code is take from Gerd Hoffmann <kraxel at redhat.com>'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/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 */
+static void virtio_vsock_rx_fill(struct virtio_vsock *vsock);
+
+struct virtio_vsock {
+ /* Virtio device */
+ struct virtio_device *vdev;
+ /* Virtio virtqueue */
+ struct virtqueue *vqs[VSOCK_VQ_MAX];
+ /* Wait queue for send pkt */
+ wait_queue_head_t queue_wait;
+ /* Work item to send pkt */
+ struct work_struct tx_work;
+ /* Work item to recv pkt */
+ struct work_struct rx_work;
+ /* Mutex to protect send pkt*/
+ struct mutex tx_lock;
+ /* Mutex to protect recv pkt*/
+ struct mutex rx_lock;
+ /* Number of recv buffers */
+ int rx_buf_nr;
+ /* Number of max recv buffers */
+ int rx_buf_max_nr;
+ /* Used for global tx buf limitation */
+ u32 total_tx_buf;
+ /* Guest context id, just like guest ip address */
+ 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 int
+virtio_transport_send_pkt(struct vsock_sock *vsk,
+ struct virtio_vsock_pkt_info *info)
+{
+ u32 src_cid, src_port, dst_cid, dst_port;
+ int ret, in_sg = 0, out_sg = 0;
+ struct virtio_transport *trans;
+ struct virtio_vsock_pkt *pkt;
+ struct virtio_vsock *vsock;
+ struct scatterlist hdr, buf, *sgs[2];
+ struct virtqueue *vq;
+ u32 pkt_len = info->pkt_len;
+ DEFINE_WAIT(wait);
+
+ vsock = virtio_vsock_get();
+ if (!vsock)
+ return -ENODEV;
+
+ src_cid = virtio_transport_get_local_cid();
+ src_port = vsk->local_addr.svm_port;
+ if (!info->remote_cid) {
+ dst_cid = vsk->remote_addr.svm_cid;
+ dst_port = vsk->remote_addr.svm_port;
+ } else {
+ dst_cid = info->remote_cid;
+ dst_port = info->remote_port;
+ }
+
+ trans = vsk->trans;
+ vq = vsock->vqs[VSOCK_VQ_TX];
+
+ if (pkt_len > VIRTIO_VSOCK_DEFAULT_RX_BUF_SIZE)
+ pkt_len = VIRTIO_VSOCK_DEFAULT_RX_BUF_SIZE;
+ pkt_len = virtio_transport_get_credit(trans, pkt_len);
+ /* Do not send zero length OP_RW pkt*/
+ if (pkt_len == 0 && info->op == VIRTIO_VSOCK_OP_RW)
+ return pkt_len;
+
+ /* Respect global tx buf limitation */
+ mutex_lock(&vsock->tx_lock);
+ while (pkt_len + vsock->total_tx_buf > VIRTIO_VSOCK_MAX_TX_BUF_SIZE) {
+ prepare_to_wait_exclusive(&vsock->queue_wait, &wait,
+ TASK_UNINTERRUPTIBLE);
+ mutex_unlock(&vsock->tx_lock);
+ schedule();
+ mutex_lock(&vsock->tx_lock);
+ finish_wait(&vsock->queue_wait, &wait);
+ }
+ vsock->total_tx_buf += pkt_len;
+ mutex_unlock(&vsock->tx_lock);
+
+ pkt = virtio_transport_alloc_pkt(vsk, info, pkt_len,
+ src_cid, src_port,
+ dst_cid, dst_port);
+ if (!pkt) {
+ mutex_lock(&vsock->tx_lock);
+ vsock->total_tx_buf -= pkt_len;
+ mutex_unlock(&vsock->tx_lock);
+ virtio_transport_put_credit(trans, pkt_len);
+ return -ENOMEM;
+ }
+
+ pr_debug("%s:info->pkt_len= %d\n", __func__, info->pkt_len);
+
+ /* Will be released in virtio_transport_send_pkt_work */
+ sock_hold(&trans->vsk->sk);
+ virtio_transport_inc_tx_pkt(pkt);
+
+ /* Put pkt in the virtqueue */
+ sg_init_one(&hdr, &pkt->hdr, sizeof(pkt->hdr));
+ sgs[out_sg++] = &hdr;
+ if (info->msg && info->pkt_len > 0) {
+ sg_init_one(&buf, pkt->buf, pkt->len);
+ sgs[out_sg++] = &buf;
+ }
+
+ mutex_lock(&vsock->tx_lock);
+ while ((ret = virtqueue_add_sgs(vq, sgs, out_sg, in_sg, pkt,
+ GFP_KERNEL)) < 0) {
+ prepare_to_wait_exclusive(&vsock->queue_wait, &wait,
+ TASK_UNINTERRUPTIBLE);
+ mutex_unlock(&vsock->tx_lock);
+ schedule();
+ mutex_lock(&vsock->tx_lock);
+ finish_wait(&vsock->queue_wait, &wait);
+ }
+ virtqueue_kick(vq);
+ mutex_unlock(&vsock->tx_lock);
+
+ return pkt_len;
+}
+
+static struct virtio_transport_pkt_ops virtio_ops = {
+ .send_pkt = virtio_transport_send_pkt,
+};
+
+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) {
+ pr_debug("%s: fail to allocate pkt\n", __func__);
+ goto out;
+ }
+
+ /* TODO: use mergeable rx buffer */
+ pkt->buf = kmalloc(buf_len, GFP_KERNEL);
+ if (!pkt->buf) {
+ pr_debug("%s: fail to allocate pkt->buf\n", __func__);
+ goto err;
+ }
+
+ 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)
+ goto err;
+ 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;
+out:
+ virtqueue_kick(vq);
+ return;
+err:
+ virtqueue_kick(vq);
+ virtio_transport_free_pkt(pkt);
+ return;
+}
+
+static void virtio_transport_send_pkt_work(struct work_struct *work)
+{
+ struct virtio_vsock *vsock =
+ container_of(work, struct virtio_vsock, tx_work);
+ struct virtio_vsock_pkt *pkt;
+ bool added = false;
+ struct virtqueue *vq;
+ unsigned int len;
+ struct sock *sk;
+
+ vq = vsock->vqs[VSOCK_VQ_TX];
+ mutex_lock(&vsock->tx_lock);
+ do {
+ virtqueue_disable_cb(vq);
+ while ((pkt = virtqueue_get_buf(vq, &len)) != NULL) {
+ sk = &pkt->trans->vsk->sk;
+ virtio_transport_dec_tx_pkt(pkt);
+ /* Release refcnt taken in virtio_transport_send_pkt */
+ sock_put(sk);
+ vsock->total_tx_buf -= pkt->len;
+ virtio_transport_free_pkt(pkt);
+ added = true;
+ }
+ } while (!virtqueue_enable_cb(vq));
+ mutex_unlock(&vsock->tx_lock);
+
+ if (added)
+ wake_up(&vsock->queue_wait);
+}
+
+static void virtio_transport_recv_pkt_work(struct work_struct *work)
+{
+ struct virtio_vsock *vsock =
+ container_of(work, struct virtio_vsock, rx_work);
+ struct virtio_vsock_pkt *pkt;
+ struct virtqueue *vq;
+ unsigned int len;
+
+ vq = vsock->vqs[VSOCK_VQ_RX];
+ mutex_lock(&vsock->rx_lock);
+ do {
+ virtqueue_disable_cb(vq);
+ while ((pkt = virtqueue_get_buf(vq, &len)) != NULL) {
+ pkt->len = len;
+ virtio_transport_recv_pkt(pkt);
+ vsock->rx_buf_nr--;
+ }
+ } while (!virtqueue_enable_cb(vq));
+
+ if (vsock->rx_buf_nr < vsock->rx_buf_max_nr / 2)
+ virtio_vsock_rx_fill(vsock);
+ mutex_unlock(&vsock->rx_lock);
+}
+
+static void virtio_vsock_ctrl_done(struct virtqueue *vq)
+{
+}
+
+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 int
+virtio_transport_socket_init(struct vsock_sock *vsk, struct vsock_sock *psk)
+{
+ struct virtio_transport *trans;
+ int ret;
+
+ ret = virtio_transport_do_socket_init(vsk, psk);
+ if (ret)
+ return ret;
+
+ trans = vsk->trans;
+ trans->ops = &virtio_ops;
+ return ret;
+}
+
+static struct vsock_transport virtio_transport = {
+ .get_local_cid = virtio_transport_get_local_cid,
+
+ .init = virtio_transport_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,
+};
+
+static int virtio_vsock_probe(struct virtio_device *vdev)
+{
+ vq_callback_t *callbacks[] = {
+ virtio_vsock_ctrl_done,
+ virtio_vsock_rx_done,
+ virtio_vsock_tx_done,
+ };
+ const char *names[] = {
+ "ctrl",
+ "rx",
+ "tx",
+ };
+ struct virtio_vsock *vsock = NULL;
+ u32 guest_cid;
+ 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;
+
+ vdev->config->get(vdev, offsetof(struct virtio_vsock_config, guest_cid),
+ &guest_cid, sizeof(guest_cid));
+ vsock->guest_cid = le32_to_cpu(guest_cid);
+ pr_debug("%s:guest_cid=%d\n", __func__, vsock->guest_cid);
+
+ ret = vsock_core_init(&virtio_transport);
+ if (ret < 0)
+ goto out_vqs;
+
+ vsock->rx_buf_nr = 0;
+ vsock->rx_buf_max_nr = 0;
+
+ vdev->priv = the_virtio_vsock = vsock;
+ init_waitqueue_head(&vsock->queue_wait);
+ mutex_init(&vsock->tx_lock);
+ mutex_init(&vsock->rx_lock);
+ INIT_WORK(&vsock->rx_work, virtio_transport_recv_pkt_work);
+ INIT_WORK(&vsock->tx_work, virtio_transport_send_pkt_work);
+
+ mutex_lock(&vsock->rx_lock);
+ virtio_vsock_rx_fill(vsock);
+ mutex_unlock(&vsock->rx_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;
+
+ mutex_lock(&the_virtio_vsock_mutex);
+ the_virtio_vsock = NULL;
+ vsock_core_exit();
+ mutex_unlock(&the_virtio_vsock_mutex);
+
+ 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);
--
2.5.0
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