diff options
Diffstat (limited to 'drivers/vhost/net.c')
| -rw-r--r-- | drivers/vhost/net.c | 669 |
1 files changed, 669 insertions, 0 deletions
diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c new file mode 100644 index 0000000..ad37da2 --- /dev/null +++ b/drivers/vhost/net.c @@ -0,0 +1,669 @@ +/* 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; + } + sock = get_socket(fd); + if (IS_ERR(sock)) { + r = PTR_ERR(sock); + goto err; + } + + /* 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); + mutex_unlock(&vq->mutex); +done: + if (oldsock) { + vhost_net_flush_vq(n, index); + fput(oldsock->file); + } +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"); |
