diff options
Diffstat (limited to 'net/vmw_vsock/virtio_transport.c')
| -rw-r--r-- | net/vmw_vsock/virtio_transport.c | 754 |
1 files changed, 754 insertions, 0 deletions
diff --git a/net/vmw_vsock/virtio_transport.c b/net/vmw_vsock/virtio_transport.c new file mode 100644 index 000000000..e13112153 --- /dev/null +++ b/net/vmw_vsock/virtio_transport.c @@ -0,0 +1,754 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * virtio transport for vsock + * + * Copyright (C) 2013-2015 Red Hat, Inc. + * Author: Asias He <asias@redhat.com> + * Stefan Hajnoczi <stefanha@redhat.com> + * + * Some of the code is take from Gerd Hoffmann <kraxel@redhat.com>'s + * early virtio-vsock proof-of-concept bits. + */ +#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 __rcu *the_virtio_vsock; +static DEFINE_MUTEX(the_virtio_vsock_mutex); /* protects the_virtio_vsock */ +static struct virtio_transport virtio_transport; /* forward declaration */ + +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; + bool tx_run; + + 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; + bool rx_run; + 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; + bool event_run; + struct virtio_vsock_event event_list[8]; + + u32 guest_cid; +}; + +static u32 virtio_transport_get_local_cid(void) +{ + struct virtio_vsock *vsock; + u32 ret; + + rcu_read_lock(); + vsock = rcu_dereference(the_virtio_vsock); + if (!vsock) { + ret = VMADDR_CID_ANY; + goto out_rcu; + } + + ret = vsock->guest_cid; +out_rcu: + rcu_read_unlock(); + return ret; +} + +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); + + if (!vsock->tx_run) + goto out; + + vq = vsock->vqs[VSOCK_VQ_TX]; + + 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); + 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); + + virtio_transport_deliver_tap_pkt(pkt); + + 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); + /* Usually this means that there is no more space available in + * the vq + */ + 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); + 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); + +out: + 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; + + rcu_read_lock(); + vsock = rcu_dereference(the_virtio_vsock); + if (!vsock) { + virtio_transport_free_pkt(pkt); + len = -ENODEV; + goto out_rcu; + } + + if (le64_to_cpu(pkt->hdr.dst_cid) == vsock->guest_cid) { + virtio_transport_free_pkt(pkt); + len = -ENODEV; + goto out_rcu; + } + + 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); + +out_rcu: + rcu_read_unlock(); + return len; +} + +static int +virtio_transport_cancel_pkt(struct vsock_sock *vsk) +{ + struct virtio_vsock *vsock; + struct virtio_vsock_pkt *pkt, *n; + int cnt = 0, ret; + LIST_HEAD(freeme); + + rcu_read_lock(); + vsock = rcu_dereference(the_virtio_vsock); + if (!vsock) { + ret = -ENODEV; + goto out_rcu; + } + + spin_lock_bh(&vsock->send_pkt_list_lock); + list_for_each_entry_safe(pkt, n, &vsock->send_pkt_list, list) { + if (pkt->vsk != vsk) + continue; + list_move(&pkt->list, &freeme); + } + spin_unlock_bh(&vsock->send_pkt_list_lock); + + list_for_each_entry_safe(pkt, n, &freeme, list) { + if (pkt->reply) + cnt++; + list_del(&pkt->list); + virtio_transport_free_pkt(pkt); + } + + if (cnt) { + struct virtqueue *rx_vq = vsock->vqs[VSOCK_VQ_RX]; + int new_cnt; + + new_cnt = atomic_sub_return(cnt, &vsock->queued_replies); + if (new_cnt + cnt >= virtqueue_get_vring_size(rx_vq) && + new_cnt < virtqueue_get_vring_size(rx_vq)) + queue_work(virtio_vsock_workqueue, &vsock->rx_work); + } + + ret = 0; + +out_rcu: + rcu_read_unlock(); + return ret; +} + +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->buf_len = buf_len; + 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); + + if (!vsock->tx_run) + goto out; + + 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)); + +out: + 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); +} + +/* 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) +{ + /* vmci_transport.c doesn't take sk_lock here either. At least we're + * under vsock_table_lock so the sock cannot disappear while we're + * executing. + */ + + sk->sk_state = TCP_CLOSE; + sk->sk_err = ECONNRESET; + sk->sk_error_report(sk); +} + +static void virtio_vsock_update_guest_cid(struct virtio_vsock *vsock) +{ + struct virtio_device *vdev = vsock->vdev; + __le64 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_transport.transport, + 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); + + if (!vsock->event_run) + goto out; + + 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]); +out: + 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 = { + .module = THIS_MODULE, + + .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, + .cancel_pkt = virtio_transport_cancel_pkt, + + .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, + .notify_buffer_size = virtio_transport_notify_buffer_size, + }, + + .send_pkt = virtio_transport_send_pkt, +}; + +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); + + if (!vsock->rx_run) + goto out; + + 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_deliver_tap_pkt(pkt); + virtio_transport_recv_pkt(&virtio_transport, 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); +} + +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 (rcu_dereference_protected(the_virtio_vsock, + lockdep_is_held(&the_virtio_vsock_mutex))) { + ret = -EBUSY; + goto out; + } + + vsock = kzalloc(sizeof(*vsock), GFP_KERNEL); + if (!vsock) { + ret = -ENOMEM; + goto out; + } + + vsock->vdev = vdev; + + ret = virtio_find_vqs(vsock->vdev, VSOCK_VQ_MAX, + vsock->vqs, callbacks, names, + NULL); + if (ret < 0) + goto out; + + virtio_vsock_update_guest_cid(vsock); + + vsock->rx_buf_nr = 0; + vsock->rx_buf_max_nr = 0; + atomic_set(&vsock->queued_replies, 0); + + 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->tx_lock); + vsock->tx_run = true; + mutex_unlock(&vsock->tx_lock); + + mutex_lock(&vsock->rx_lock); + virtio_vsock_rx_fill(vsock); + vsock->rx_run = true; + mutex_unlock(&vsock->rx_lock); + + mutex_lock(&vsock->event_lock); + virtio_vsock_event_fill(vsock); + vsock->event_run = true; + mutex_unlock(&vsock->event_lock); + + vdev->priv = vsock; + rcu_assign_pointer(the_virtio_vsock, vsock); + + mutex_unlock(&the_virtio_vsock_mutex); + return 0; + +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; + + mutex_lock(&the_virtio_vsock_mutex); + + vdev->priv = NULL; + rcu_assign_pointer(the_virtio_vsock, NULL); + synchronize_rcu(); + + /* Reset all connected sockets when the device disappear */ + vsock_for_each_connected_socket(&virtio_transport.transport, + virtio_vsock_reset_sock); + + /* Stop all work handlers to make sure no one is accessing the device, + * so we can safely call vdev->config->reset(). + */ + mutex_lock(&vsock->rx_lock); + vsock->rx_run = false; + mutex_unlock(&vsock->rx_lock); + + mutex_lock(&vsock->tx_lock); + vsock->tx_run = false; + mutex_unlock(&vsock->tx_lock); + + mutex_lock(&vsock->event_lock); + vsock->event_run = false; + mutex_unlock(&vsock->event_lock); + + /* Flush all device writes and interrupts, device will not use any + * more buffers. + */ + 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); + + /* Delete virtqueues and flush outstanding callbacks if any */ + vdev->config->del_vqs(vdev); + + /* Other works can be queued before 'config->del_vqs()', so we flush + * all works before to free the vsock object to avoid use after free. + */ + flush_work(&vsock->rx_work); + flush_work(&vsock->tx_work); + flush_work(&vsock->event_work); + flush_work(&vsock->send_pkt_work); + + 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 = vsock_core_register(&virtio_transport.transport, + VSOCK_TRANSPORT_F_G2H); + if (ret) + goto out_wq; + + ret = register_virtio_driver(&virtio_vsock_driver); + if (ret) + goto out_vci; + + return 0; + +out_vci: + vsock_core_unregister(&virtio_transport.transport); +out_wq: + destroy_workqueue(virtio_vsock_workqueue); + return ret; +} + +static void __exit virtio_vsock_exit(void) +{ + unregister_virtio_driver(&virtio_vsock_driver); + vsock_core_unregister(&virtio_transport.transport); + 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); |