| /* Copyright (C) 2009 Red Hat, Inc. |
| * Author: Michael S. Tsirkin <mst@redhat.com> |
| * |
| * This work is licensed under the terms of the GNU GPL, version 2. |
| * |
| * virtio-net server in host kernel. |
| */ |
| |
| #include <linux/compat.h> |
| #include <linux/eventfd.h> |
| #include <linux/vhost.h> |
| #include <linux/virtio_net.h> |
| #include <linux/mmu_context.h> |
| #include <linux/miscdevice.h> |
| #include <linux/module.h> |
| #include <linux/mutex.h> |
| #include <linux/workqueue.h> |
| #include <linux/rcupdate.h> |
| #include <linux/file.h> |
| |
| #include <linux/net.h> |
| #include <linux/if_packet.h> |
| #include <linux/if_arp.h> |
| #include <linux/if_tun.h> |
| #include <linux/if_macvlan.h> |
| |
| #include <net/sock.h> |
| |
| #include "vhost.h" |
| |
| /* Max number of bytes transferred before requeueing the job. |
| * Using this limit prevents one virtqueue from starving others. */ |
| #define VHOST_NET_WEIGHT 0x80000 |
| |
| enum { |
| VHOST_NET_VQ_RX = 0, |
| VHOST_NET_VQ_TX = 1, |
| VHOST_NET_VQ_MAX = 2, |
| }; |
| |
| enum vhost_net_poll_state { |
| VHOST_NET_POLL_DISABLED = 0, |
| VHOST_NET_POLL_STARTED = 1, |
| VHOST_NET_POLL_STOPPED = 2, |
| }; |
| |
| struct vhost_net { |
| struct vhost_dev dev; |
| struct vhost_virtqueue vqs[VHOST_NET_VQ_MAX]; |
| struct vhost_poll poll[VHOST_NET_VQ_MAX]; |
| /* Tells us whether we are polling a socket for TX. |
| * We only do this when socket buffer fills up. |
| * Protected by tx vq lock. */ |
| enum vhost_net_poll_state tx_poll_state; |
| }; |
| |
| /* Pop first len bytes from iovec. Return number of segments used. */ |
| static int move_iovec_hdr(struct iovec *from, struct iovec *to, |
| size_t len, int iov_count) |
| { |
| int seg = 0; |
| size_t size; |
| while (len && seg < iov_count) { |
| size = min(from->iov_len, len); |
| to->iov_base = from->iov_base; |
| to->iov_len = size; |
| from->iov_len -= size; |
| from->iov_base += size; |
| len -= size; |
| ++from; |
| ++to; |
| ++seg; |
| } |
| return seg; |
| } |
| |
| /* Caller must have TX VQ lock */ |
| static void tx_poll_stop(struct vhost_net *net) |
| { |
| if (likely(net->tx_poll_state != VHOST_NET_POLL_STARTED)) |
| return; |
| vhost_poll_stop(net->poll + VHOST_NET_VQ_TX); |
| net->tx_poll_state = VHOST_NET_POLL_STOPPED; |
| } |
| |
| /* Caller must have TX VQ lock */ |
| static void tx_poll_start(struct vhost_net *net, struct socket *sock) |
| { |
| if (unlikely(net->tx_poll_state != VHOST_NET_POLL_STOPPED)) |
| return; |
| vhost_poll_start(net->poll + VHOST_NET_VQ_TX, sock->file); |
| net->tx_poll_state = VHOST_NET_POLL_STARTED; |
| } |
| |
| /* Expects to be always run from workqueue - which acts as |
| * read-size critical section for our kind of RCU. */ |
| static void handle_tx(struct vhost_net *net) |
| { |
| struct vhost_virtqueue *vq = &net->dev.vqs[VHOST_NET_VQ_TX]; |
| unsigned head, out, in, s; |
| struct msghdr msg = { |
| .msg_name = NULL, |
| .msg_namelen = 0, |
| .msg_control = NULL, |
| .msg_controllen = 0, |
| .msg_iov = vq->iov, |
| .msg_flags = MSG_DONTWAIT, |
| }; |
| size_t len, total_len = 0; |
| int err, wmem; |
| size_t hdr_size; |
| struct socket *sock = rcu_dereference(vq->private_data); |
| if (!sock) |
| return; |
| |
| wmem = atomic_read(&sock->sk->sk_wmem_alloc); |
| if (wmem >= sock->sk->sk_sndbuf) { |
| mutex_lock(&vq->mutex); |
| tx_poll_start(net, sock); |
| mutex_unlock(&vq->mutex); |
| return; |
| } |
| |
| use_mm(net->dev.mm); |
| mutex_lock(&vq->mutex); |
| vhost_disable_notify(vq); |
| |
| if (wmem < sock->sk->sk_sndbuf / 2) |
| tx_poll_stop(net); |
| hdr_size = vq->hdr_size; |
| |
| for (;;) { |
| head = vhost_get_vq_desc(&net->dev, vq, vq->iov, |
| ARRAY_SIZE(vq->iov), |
| &out, &in, |
| NULL, NULL); |
| /* Nothing new? Wait for eventfd to tell us they refilled. */ |
| if (head == vq->num) { |
| wmem = atomic_read(&sock->sk->sk_wmem_alloc); |
| if (wmem >= sock->sk->sk_sndbuf * 3 / 4) { |
| tx_poll_start(net, sock); |
| set_bit(SOCK_ASYNC_NOSPACE, &sock->flags); |
| break; |
| } |
| if (unlikely(vhost_enable_notify(vq))) { |
| vhost_disable_notify(vq); |
| continue; |
| } |
| break; |
| } |
| if (in) { |
| vq_err(vq, "Unexpected descriptor format for TX: " |
| "out %d, int %d\n", out, in); |
| break; |
| } |
| /* Skip header. TODO: support TSO. */ |
| s = move_iovec_hdr(vq->iov, vq->hdr, hdr_size, out); |
| msg.msg_iovlen = out; |
| len = iov_length(vq->iov, out); |
| /* Sanity check */ |
| if (!len) { |
| vq_err(vq, "Unexpected header len for TX: " |
| "%zd expected %zd\n", |
| iov_length(vq->hdr, s), hdr_size); |
| break; |
| } |
| /* TODO: Check specific error and bomb out unless ENOBUFS? */ |
| err = sock->ops->sendmsg(NULL, sock, &msg, len); |
| if (unlikely(err < 0)) { |
| vhost_discard_vq_desc(vq); |
| tx_poll_start(net, sock); |
| break; |
| } |
| if (err != len) |
| pr_err("Truncated TX packet: " |
| " len %d != %zd\n", err, len); |
| vhost_add_used_and_signal(&net->dev, vq, head, 0); |
| total_len += len; |
| if (unlikely(total_len >= VHOST_NET_WEIGHT)) { |
| vhost_poll_queue(&vq->poll); |
| break; |
| } |
| } |
| |
| mutex_unlock(&vq->mutex); |
| unuse_mm(net->dev.mm); |
| } |
| |
| /* Expects to be always run from workqueue - which acts as |
| * read-size critical section for our kind of RCU. */ |
| static void handle_rx(struct vhost_net *net) |
| { |
| struct vhost_virtqueue *vq = &net->dev.vqs[VHOST_NET_VQ_RX]; |
| unsigned head, out, in, log, s; |
| struct vhost_log *vq_log; |
| struct msghdr msg = { |
| .msg_name = NULL, |
| .msg_namelen = 0, |
| .msg_control = NULL, /* FIXME: get and handle RX aux data. */ |
| .msg_controllen = 0, |
| .msg_iov = vq->iov, |
| .msg_flags = MSG_DONTWAIT, |
| }; |
| |
| struct virtio_net_hdr hdr = { |
| .flags = 0, |
| .gso_type = VIRTIO_NET_HDR_GSO_NONE |
| }; |
| |
| size_t len, total_len = 0; |
| int err; |
| size_t hdr_size; |
| struct socket *sock = rcu_dereference(vq->private_data); |
| if (!sock || skb_queue_empty(&sock->sk->sk_receive_queue)) |
| return; |
| |
| use_mm(net->dev.mm); |
| mutex_lock(&vq->mutex); |
| vhost_disable_notify(vq); |
| hdr_size = vq->hdr_size; |
| |
| vq_log = unlikely(vhost_has_feature(&net->dev, VHOST_F_LOG_ALL)) ? |
| vq->log : NULL; |
| |
| for (;;) { |
| head = vhost_get_vq_desc(&net->dev, vq, vq->iov, |
| ARRAY_SIZE(vq->iov), |
| &out, &in, |
| vq_log, &log); |
| /* OK, now we need to know about added descriptors. */ |
| if (head == vq->num) { |
| if (unlikely(vhost_enable_notify(vq))) { |
| /* They have slipped one in as we were |
| * doing that: check again. */ |
| vhost_disable_notify(vq); |
| continue; |
| } |
| /* Nothing new? Wait for eventfd to tell us |
| * they refilled. */ |
| break; |
| } |
| /* We don't need to be notified again. */ |
| if (out) { |
| vq_err(vq, "Unexpected descriptor format for RX: " |
| "out %d, int %d\n", |
| out, in); |
| break; |
| } |
| /* Skip header. TODO: support TSO/mergeable rx buffers. */ |
| s = move_iovec_hdr(vq->iov, vq->hdr, hdr_size, in); |
| msg.msg_iovlen = in; |
| len = iov_length(vq->iov, in); |
| /* Sanity check */ |
| if (!len) { |
| vq_err(vq, "Unexpected header len for RX: " |
| "%zd expected %zd\n", |
| iov_length(vq->hdr, s), hdr_size); |
| break; |
| } |
| err = sock->ops->recvmsg(NULL, sock, &msg, |
| len, MSG_DONTWAIT | MSG_TRUNC); |
| /* TODO: Check specific error and bomb out unless EAGAIN? */ |
| if (err < 0) { |
| vhost_discard_vq_desc(vq); |
| break; |
| } |
| /* TODO: Should check and handle checksum. */ |
| if (err > len) { |
| pr_err("Discarded truncated rx packet: " |
| " len %d > %zd\n", err, len); |
| vhost_discard_vq_desc(vq); |
| continue; |
| } |
| len = err; |
| err = memcpy_toiovec(vq->hdr, (unsigned char *)&hdr, hdr_size); |
| if (err) { |
| vq_err(vq, "Unable to write vnet_hdr at addr %p: %d\n", |
| vq->iov->iov_base, err); |
| break; |
| } |
| len += hdr_size; |
| vhost_add_used_and_signal(&net->dev, vq, head, len); |
| if (unlikely(vq_log)) |
| vhost_log_write(vq, vq_log, log, len); |
| total_len += len; |
| if (unlikely(total_len >= VHOST_NET_WEIGHT)) { |
| vhost_poll_queue(&vq->poll); |
| break; |
| } |
| } |
| |
| mutex_unlock(&vq->mutex); |
| unuse_mm(net->dev.mm); |
| } |
| |
| static void handle_tx_kick(struct work_struct *work) |
| { |
| struct vhost_virtqueue *vq; |
| struct vhost_net *net; |
| vq = container_of(work, struct vhost_virtqueue, poll.work); |
| net = container_of(vq->dev, struct vhost_net, dev); |
| handle_tx(net); |
| } |
| |
| static void handle_rx_kick(struct work_struct *work) |
| { |
| struct vhost_virtqueue *vq; |
| struct vhost_net *net; |
| vq = container_of(work, struct vhost_virtqueue, poll.work); |
| net = container_of(vq->dev, struct vhost_net, dev); |
| handle_rx(net); |
| } |
| |
| static void handle_tx_net(struct work_struct *work) |
| { |
| struct vhost_net *net; |
| net = container_of(work, struct vhost_net, poll[VHOST_NET_VQ_TX].work); |
| handle_tx(net); |
| } |
| |
| static void handle_rx_net(struct work_struct *work) |
| { |
| struct vhost_net *net; |
| net = container_of(work, struct vhost_net, poll[VHOST_NET_VQ_RX].work); |
| handle_rx(net); |
| } |
| |
| static int vhost_net_open(struct inode *inode, struct file *f) |
| { |
| struct vhost_net *n = kmalloc(sizeof *n, GFP_KERNEL); |
| int r; |
| if (!n) |
| return -ENOMEM; |
| n->vqs[VHOST_NET_VQ_TX].handle_kick = handle_tx_kick; |
| n->vqs[VHOST_NET_VQ_RX].handle_kick = handle_rx_kick; |
| r = vhost_dev_init(&n->dev, n->vqs, VHOST_NET_VQ_MAX); |
| if (r < 0) { |
| kfree(n); |
| return r; |
| } |
| |
| vhost_poll_init(n->poll + VHOST_NET_VQ_TX, handle_tx_net, POLLOUT); |
| vhost_poll_init(n->poll + VHOST_NET_VQ_RX, handle_rx_net, POLLIN); |
| n->tx_poll_state = VHOST_NET_POLL_DISABLED; |
| |
| f->private_data = n; |
| |
| return 0; |
| } |
| |
| static void vhost_net_disable_vq(struct vhost_net *n, |
| struct vhost_virtqueue *vq) |
| { |
| if (!vq->private_data) |
| return; |
| if (vq == n->vqs + VHOST_NET_VQ_TX) { |
| tx_poll_stop(n); |
| n->tx_poll_state = VHOST_NET_POLL_DISABLED; |
| } else |
| vhost_poll_stop(n->poll + VHOST_NET_VQ_RX); |
| } |
| |
| static void vhost_net_enable_vq(struct vhost_net *n, |
| struct vhost_virtqueue *vq) |
| { |
| struct socket *sock = vq->private_data; |
| if (!sock) |
| return; |
| if (vq == n->vqs + VHOST_NET_VQ_TX) { |
| n->tx_poll_state = VHOST_NET_POLL_STOPPED; |
| tx_poll_start(n, sock); |
| } else |
| vhost_poll_start(n->poll + VHOST_NET_VQ_RX, sock->file); |
| } |
| |
| static struct socket *vhost_net_stop_vq(struct vhost_net *n, |
| struct vhost_virtqueue *vq) |
| { |
| struct socket *sock; |
| |
| mutex_lock(&vq->mutex); |
| sock = vq->private_data; |
| vhost_net_disable_vq(n, vq); |
| rcu_assign_pointer(vq->private_data, NULL); |
| mutex_unlock(&vq->mutex); |
| return sock; |
| } |
| |
| static void vhost_net_stop(struct vhost_net *n, struct socket **tx_sock, |
| struct socket **rx_sock) |
| { |
| *tx_sock = vhost_net_stop_vq(n, n->vqs + VHOST_NET_VQ_TX); |
| *rx_sock = vhost_net_stop_vq(n, n->vqs + VHOST_NET_VQ_RX); |
| } |
| |
| static void vhost_net_flush_vq(struct vhost_net *n, int index) |
| { |
| vhost_poll_flush(n->poll + index); |
| vhost_poll_flush(&n->dev.vqs[index].poll); |
| } |
| |
| static void vhost_net_flush(struct vhost_net *n) |
| { |
| vhost_net_flush_vq(n, VHOST_NET_VQ_TX); |
| vhost_net_flush_vq(n, VHOST_NET_VQ_RX); |
| } |
| |
| static int vhost_net_release(struct inode *inode, struct file *f) |
| { |
| struct vhost_net *n = f->private_data; |
| struct socket *tx_sock; |
| struct socket *rx_sock; |
| |
| vhost_net_stop(n, &tx_sock, &rx_sock); |
| vhost_net_flush(n); |
| vhost_dev_cleanup(&n->dev); |
| if (tx_sock) |
| fput(tx_sock->file); |
| if (rx_sock) |
| fput(rx_sock->file); |
| /* We do an extra flush before freeing memory, |
| * since jobs can re-queue themselves. */ |
| vhost_net_flush(n); |
| kfree(n); |
| return 0; |
| } |
| |
| static struct socket *get_raw_socket(int fd) |
| { |
| struct { |
| struct sockaddr_ll sa; |
| char buf[MAX_ADDR_LEN]; |
| } uaddr; |
| int uaddr_len = sizeof uaddr, r; |
| struct socket *sock = sockfd_lookup(fd, &r); |
| if (!sock) |
| return ERR_PTR(-ENOTSOCK); |
| |
| /* Parameter checking */ |
| if (sock->sk->sk_type != SOCK_RAW) { |
| r = -ESOCKTNOSUPPORT; |
| goto err; |
| } |
| |
| r = sock->ops->getname(sock, (struct sockaddr *)&uaddr.sa, |
| &uaddr_len, 0); |
| if (r) |
| goto err; |
| |
| if (uaddr.sa.sll_family != AF_PACKET) { |
| r = -EPFNOSUPPORT; |
| goto err; |
| } |
| return sock; |
| err: |
| fput(sock->file); |
| return ERR_PTR(r); |
| } |
| |
| static struct socket *get_tap_socket(int fd) |
| { |
| struct file *file = fget(fd); |
| struct socket *sock; |
| if (!file) |
| return ERR_PTR(-EBADF); |
| sock = tun_get_socket(file); |
| if (!IS_ERR(sock)) |
| return sock; |
| sock = macvtap_get_socket(file); |
| if (IS_ERR(sock)) |
| fput(file); |
| return sock; |
| } |
| |
| static struct socket *get_socket(int fd) |
| { |
| struct socket *sock; |
| /* special case to disable backend */ |
| if (fd == -1) |
| return NULL; |
| sock = get_raw_socket(fd); |
| if (!IS_ERR(sock)) |
| return sock; |
| sock = get_tap_socket(fd); |
| if (!IS_ERR(sock)) |
| return sock; |
| return ERR_PTR(-ENOTSOCK); |
| } |
| |
| static long vhost_net_set_backend(struct vhost_net *n, unsigned index, int fd) |
| { |
| struct socket *sock, *oldsock; |
| struct vhost_virtqueue *vq; |
| int r; |
| |
| mutex_lock(&n->dev.mutex); |
| r = vhost_dev_check_owner(&n->dev); |
| if (r) |
| goto err; |
| |
| if (index >= VHOST_NET_VQ_MAX) { |
| r = -ENOBUFS; |
| goto err; |
| } |
| vq = n->vqs + index; |
| mutex_lock(&vq->mutex); |
| |
| /* Verify that ring has been setup correctly. */ |
| if (!vhost_vq_access_ok(vq)) { |
| r = -EFAULT; |
| goto err_vq; |
| } |
| sock = get_socket(fd); |
| if (IS_ERR(sock)) { |
| r = PTR_ERR(sock); |
| goto err_vq; |
| } |
| |
| /* start polling new socket */ |
| oldsock = vq->private_data; |
| if (sock == oldsock) |
| goto done; |
| |
| vhost_net_disable_vq(n, vq); |
| rcu_assign_pointer(vq->private_data, sock); |
| vhost_net_enable_vq(n, vq); |
| done: |
| if (oldsock) { |
| vhost_net_flush_vq(n, index); |
| fput(oldsock->file); |
| } |
| |
| err_vq: |
| mutex_unlock(&vq->mutex); |
| err: |
| mutex_unlock(&n->dev.mutex); |
| return r; |
| } |
| |
| static long vhost_net_reset_owner(struct vhost_net *n) |
| { |
| struct socket *tx_sock = NULL; |
| struct socket *rx_sock = NULL; |
| long err; |
| mutex_lock(&n->dev.mutex); |
| err = vhost_dev_check_owner(&n->dev); |
| if (err) |
| goto done; |
| vhost_net_stop(n, &tx_sock, &rx_sock); |
| vhost_net_flush(n); |
| err = vhost_dev_reset_owner(&n->dev); |
| done: |
| mutex_unlock(&n->dev.mutex); |
| if (tx_sock) |
| fput(tx_sock->file); |
| if (rx_sock) |
| fput(rx_sock->file); |
| return err; |
| } |
| |
| static int vhost_net_set_features(struct vhost_net *n, u64 features) |
| { |
| size_t hdr_size = features & (1 << VHOST_NET_F_VIRTIO_NET_HDR) ? |
| sizeof(struct virtio_net_hdr) : 0; |
| int i; |
| mutex_lock(&n->dev.mutex); |
| if ((features & (1 << VHOST_F_LOG_ALL)) && |
| !vhost_log_access_ok(&n->dev)) { |
| mutex_unlock(&n->dev.mutex); |
| return -EFAULT; |
| } |
| n->dev.acked_features = features; |
| smp_wmb(); |
| for (i = 0; i < VHOST_NET_VQ_MAX; ++i) { |
| mutex_lock(&n->vqs[i].mutex); |
| n->vqs[i].hdr_size = hdr_size; |
| mutex_unlock(&n->vqs[i].mutex); |
| } |
| vhost_net_flush(n); |
| mutex_unlock(&n->dev.mutex); |
| return 0; |
| } |
| |
| static long vhost_net_ioctl(struct file *f, unsigned int ioctl, |
| unsigned long arg) |
| { |
| struct vhost_net *n = f->private_data; |
| void __user *argp = (void __user *)arg; |
| u64 __user *featurep = argp; |
| struct vhost_vring_file backend; |
| u64 features; |
| int r; |
| switch (ioctl) { |
| case VHOST_NET_SET_BACKEND: |
| r = copy_from_user(&backend, argp, sizeof backend); |
| if (r < 0) |
| return r; |
| return vhost_net_set_backend(n, backend.index, backend.fd); |
| case VHOST_GET_FEATURES: |
| features = VHOST_FEATURES; |
| return copy_to_user(featurep, &features, sizeof features); |
| case VHOST_SET_FEATURES: |
| r = copy_from_user(&features, featurep, sizeof features); |
| if (r < 0) |
| return r; |
| if (features & ~VHOST_FEATURES) |
| return -EOPNOTSUPP; |
| return vhost_net_set_features(n, features); |
| case VHOST_RESET_OWNER: |
| return vhost_net_reset_owner(n); |
| default: |
| mutex_lock(&n->dev.mutex); |
| r = vhost_dev_ioctl(&n->dev, ioctl, arg); |
| vhost_net_flush(n); |
| mutex_unlock(&n->dev.mutex); |
| return r; |
| } |
| } |
| |
| #ifdef CONFIG_COMPAT |
| static long vhost_net_compat_ioctl(struct file *f, unsigned int ioctl, |
| unsigned long arg) |
| { |
| return vhost_net_ioctl(f, ioctl, (unsigned long)compat_ptr(arg)); |
| } |
| #endif |
| |
| const static struct file_operations vhost_net_fops = { |
| .owner = THIS_MODULE, |
| .release = vhost_net_release, |
| .unlocked_ioctl = vhost_net_ioctl, |
| #ifdef CONFIG_COMPAT |
| .compat_ioctl = vhost_net_compat_ioctl, |
| #endif |
| .open = vhost_net_open, |
| }; |
| |
| static struct miscdevice vhost_net_misc = { |
| VHOST_NET_MINOR, |
| "vhost-net", |
| &vhost_net_fops, |
| }; |
| |
| int vhost_net_init(void) |
| { |
| int r = vhost_init(); |
| if (r) |
| goto err_init; |
| r = misc_register(&vhost_net_misc); |
| if (r) |
| goto err_reg; |
| return 0; |
| err_reg: |
| vhost_cleanup(); |
| err_init: |
| return r; |
| |
| } |
| module_init(vhost_net_init); |
| |
| void vhost_net_exit(void) |
| { |
| misc_deregister(&vhost_net_misc); |
| vhost_cleanup(); |
| } |
| module_exit(vhost_net_exit); |
| |
| MODULE_VERSION("0.0.1"); |
| MODULE_LICENSE("GPL v2"); |
| MODULE_AUTHOR("Michael S. Tsirkin"); |
| MODULE_DESCRIPTION("Host kernel accelerator for virtio net"); |