--- /dev/null
+/* 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 <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)
+ 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_tun_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))
+ 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_tun_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");
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff