diff options
Diffstat (limited to 'drivers/vhost/net.c')
| -rw-r--r-- | drivers/vhost/net.c | 1138 |
1 files changed, 1138 insertions, 0 deletions
diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c new file mode 100644 index 000000000..7d137a43c --- /dev/null +++ b/drivers/vhost/net.c @@ -0,0 +1,1138 @@ +/* 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/miscdevice.h> +#include <linux/module.h> +#include <linux/moduleparam.h> +#include <linux/mutex.h> +#include <linux/workqueue.h> +#include <linux/file.h> +#include <linux/slab.h> +#include <linux/vmalloc.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 <linux/if_vlan.h> + +#include <net/sock.h> + +#include "vhost.h" + +static int experimental_zcopytx = 1; +module_param(experimental_zcopytx, int, 0444); +MODULE_PARM_DESC(experimental_zcopytx, "Enable Zero Copy TX;" + " 1 -Enable; 0 - Disable"); + +/* Max number of bytes transferred before requeueing the job. + * Using this limit prevents one virtqueue from starving others. */ +#define VHOST_NET_WEIGHT 0x80000 + +/* MAX number of TX used buffers for outstanding zerocopy */ +#define VHOST_MAX_PEND 128 +#define VHOST_GOODCOPY_LEN 256 + +/* + * For transmit, used buffer len is unused; we override it to track buffer + * status internally; used for zerocopy tx only. + */ +/* Lower device DMA failed */ +#define VHOST_DMA_FAILED_LEN ((__force __virtio32)3) +/* Lower device DMA done */ +#define VHOST_DMA_DONE_LEN ((__force __virtio32)2) +/* Lower device DMA in progress */ +#define VHOST_DMA_IN_PROGRESS ((__force __virtio32)1) +/* Buffer unused */ +#define VHOST_DMA_CLEAR_LEN ((__force __virtio32)0) + +#define VHOST_DMA_IS_DONE(len) ((__force u32)(len) >= (__force u32)VHOST_DMA_DONE_LEN) + +enum { + VHOST_NET_FEATURES = VHOST_FEATURES | + (1ULL << VHOST_NET_F_VIRTIO_NET_HDR) | + (1ULL << VIRTIO_NET_F_MRG_RXBUF) | + (1ULL << VIRTIO_F_VERSION_1), +}; + +enum { + VHOST_NET_VQ_RX = 0, + VHOST_NET_VQ_TX = 1, + VHOST_NET_VQ_MAX = 2, +}; + +struct vhost_net_ubuf_ref { + /* refcount follows semantics similar to kref: + * 0: object is released + * 1: no outstanding ubufs + * >1: outstanding ubufs + */ + atomic_t refcount; + wait_queue_head_t wait; + struct vhost_virtqueue *vq; +}; + +struct vhost_net_virtqueue { + struct vhost_virtqueue vq; + size_t vhost_hlen; + size_t sock_hlen; + /* vhost zerocopy support fields below: */ + /* last used idx for outstanding DMA zerocopy buffers */ + int upend_idx; + /* first used idx for DMA done zerocopy buffers */ + int done_idx; + /* an array of userspace buffers info */ + struct ubuf_info *ubuf_info; + /* Reference counting for outstanding ubufs. + * Protected by vq mutex. Writers must also take device mutex. */ + struct vhost_net_ubuf_ref *ubufs; +}; + +struct vhost_net { + struct vhost_dev dev; + struct vhost_net_virtqueue vqs[VHOST_NET_VQ_MAX]; + struct vhost_poll poll[VHOST_NET_VQ_MAX]; + /* Number of TX recently submitted. + * Protected by tx vq lock. */ + unsigned tx_packets; + /* Number of times zerocopy TX recently failed. + * Protected by tx vq lock. */ + unsigned tx_zcopy_err; + /* Flush in progress. Protected by tx vq lock. */ + bool tx_flush; +}; + +static unsigned vhost_net_zcopy_mask __read_mostly; + +static void vhost_net_enable_zcopy(int vq) +{ + vhost_net_zcopy_mask |= 0x1 << vq; +} + +static struct vhost_net_ubuf_ref * +vhost_net_ubuf_alloc(struct vhost_virtqueue *vq, bool zcopy) +{ + struct vhost_net_ubuf_ref *ubufs; + /* No zero copy backend? Nothing to count. */ + if (!zcopy) + return NULL; + ubufs = kmalloc(sizeof(*ubufs), GFP_KERNEL); + if (!ubufs) + return ERR_PTR(-ENOMEM); + atomic_set(&ubufs->refcount, 1); + init_waitqueue_head(&ubufs->wait); + ubufs->vq = vq; + return ubufs; +} + +static int vhost_net_ubuf_put(struct vhost_net_ubuf_ref *ubufs) +{ + int r = atomic_sub_return(1, &ubufs->refcount); + if (unlikely(!r)) + wake_up(&ubufs->wait); + return r; +} + +static void vhost_net_ubuf_put_and_wait(struct vhost_net_ubuf_ref *ubufs) +{ + vhost_net_ubuf_put(ubufs); + wait_event(ubufs->wait, !atomic_read(&ubufs->refcount)); +} + +static void vhost_net_ubuf_put_wait_and_free(struct vhost_net_ubuf_ref *ubufs) +{ + vhost_net_ubuf_put_and_wait(ubufs); + kfree(ubufs); +} + +static void vhost_net_clear_ubuf_info(struct vhost_net *n) +{ + int i; + + for (i = 0; i < VHOST_NET_VQ_MAX; ++i) { + kfree(n->vqs[i].ubuf_info); + n->vqs[i].ubuf_info = NULL; + } +} + +static int vhost_net_set_ubuf_info(struct vhost_net *n) +{ + bool zcopy; + int i; + + for (i = 0; i < VHOST_NET_VQ_MAX; ++i) { + zcopy = vhost_net_zcopy_mask & (0x1 << i); + if (!zcopy) + continue; + n->vqs[i].ubuf_info = kmalloc(sizeof(*n->vqs[i].ubuf_info) * + UIO_MAXIOV, GFP_KERNEL); + if (!n->vqs[i].ubuf_info) + goto err; + } + return 0; + +err: + vhost_net_clear_ubuf_info(n); + return -ENOMEM; +} + +static void vhost_net_vq_reset(struct vhost_net *n) +{ + int i; + + vhost_net_clear_ubuf_info(n); + + for (i = 0; i < VHOST_NET_VQ_MAX; i++) { + n->vqs[i].done_idx = 0; + n->vqs[i].upend_idx = 0; + n->vqs[i].ubufs = NULL; + n->vqs[i].vhost_hlen = 0; + n->vqs[i].sock_hlen = 0; + } + +} + +static void vhost_net_tx_packet(struct vhost_net *net) +{ + ++net->tx_packets; + if (net->tx_packets < 1024) + return; + net->tx_packets = 0; + net->tx_zcopy_err = 0; +} + +static void vhost_net_tx_err(struct vhost_net *net) +{ + ++net->tx_zcopy_err; +} + +static bool vhost_net_tx_select_zcopy(struct vhost_net *net) +{ + /* TX flush waits for outstanding DMAs to be done. + * Don't start new DMAs. + */ + return !net->tx_flush && + net->tx_packets / 64 >= net->tx_zcopy_err; +} + +static bool vhost_sock_zcopy(struct socket *sock) +{ + return unlikely(experimental_zcopytx) && + sock_flag(sock->sk, SOCK_ZEROCOPY); +} + +/* In case of DMA done not in order in lower device driver for some reason. + * upend_idx is used to track end of used idx, done_idx is used to track head + * of used idx. Once lower device DMA done contiguously, we will signal KVM + * guest used idx. + */ +static void vhost_zerocopy_signal_used(struct vhost_net *net, + struct vhost_virtqueue *vq) +{ + struct vhost_net_virtqueue *nvq = + container_of(vq, struct vhost_net_virtqueue, vq); + int i, add; + int j = 0; + + for (i = nvq->done_idx; i != nvq->upend_idx; i = (i + 1) % UIO_MAXIOV) { + if (vq->heads[i].len == VHOST_DMA_FAILED_LEN) + vhost_net_tx_err(net); + if (VHOST_DMA_IS_DONE(vq->heads[i].len)) { + vq->heads[i].len = VHOST_DMA_CLEAR_LEN; + ++j; + } else + break; + } + while (j) { + add = min(UIO_MAXIOV - nvq->done_idx, j); + vhost_add_used_and_signal_n(vq->dev, vq, + &vq->heads[nvq->done_idx], add); + nvq->done_idx = (nvq->done_idx + add) % UIO_MAXIOV; + j -= add; + } +} + +static void vhost_zerocopy_callback(struct ubuf_info *ubuf, bool success) +{ + struct vhost_net_ubuf_ref *ubufs = ubuf->ctx; + struct vhost_virtqueue *vq = ubufs->vq; + int cnt; + + rcu_read_lock_bh(); + + /* set len to mark this desc buffers done DMA */ + vq->heads[ubuf->desc].len = success ? + VHOST_DMA_DONE_LEN : VHOST_DMA_FAILED_LEN; + cnt = vhost_net_ubuf_put(ubufs); + + /* + * Trigger polling thread if guest stopped submitting new buffers: + * in this case, the refcount after decrement will eventually reach 1. + * We also trigger polling periodically after each 16 packets + * (the value 16 here is more or less arbitrary, it's tuned to trigger + * less than 10% of times). + */ + if (cnt <= 1 || !(cnt % 16)) + vhost_poll_queue(&vq->poll); + + rcu_read_unlock_bh(); +} + +/* 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_net_virtqueue *nvq = &net->vqs[VHOST_NET_VQ_TX]; + struct vhost_virtqueue *vq = &nvq->vq; + unsigned out, in; + int head; + struct msghdr msg = { + .msg_name = NULL, + .msg_namelen = 0, + .msg_control = NULL, + .msg_controllen = 0, + .msg_flags = MSG_DONTWAIT, + }; + size_t len, total_len = 0; + int err; + size_t hdr_size; + struct socket *sock; + struct vhost_net_ubuf_ref *uninitialized_var(ubufs); + bool zcopy, zcopy_used; + + mutex_lock(&vq->mutex); + sock = vq->private_data; + if (!sock) + goto out; + + vhost_disable_notify(&net->dev, vq); + + hdr_size = nvq->vhost_hlen; + zcopy = nvq->ubufs; + + for (;;) { + /* Release DMAs done buffers first */ + if (zcopy) + vhost_zerocopy_signal_used(net, vq); + + /* If more outstanding DMAs, queue the work. + * Handle upend_idx wrap around + */ + if (unlikely((nvq->upend_idx + vq->num - VHOST_MAX_PEND) + % UIO_MAXIOV == nvq->done_idx)) + break; + + head = vhost_get_vq_desc(vq, vq->iov, + ARRAY_SIZE(vq->iov), + &out, &in, + NULL, NULL); + /* On error, stop handling until the next kick. */ + if (unlikely(head < 0)) + break; + /* Nothing new? Wait for eventfd to tell us they refilled. */ + if (head == vq->num) { + if (unlikely(vhost_enable_notify(&net->dev, vq))) { + vhost_disable_notify(&net->dev, 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. */ + len = iov_length(vq->iov, out); + iov_iter_init(&msg.msg_iter, WRITE, vq->iov, out, len); + iov_iter_advance(&msg.msg_iter, hdr_size); + /* Sanity check */ + if (!msg_data_left(&msg)) { + vq_err(vq, "Unexpected header len for TX: " + "%zd expected %zd\n", + len, hdr_size); + break; + } + len = msg_data_left(&msg); + + zcopy_used = zcopy && len >= VHOST_GOODCOPY_LEN + && (nvq->upend_idx + 1) % UIO_MAXIOV != + nvq->done_idx + && vhost_net_tx_select_zcopy(net); + + /* use msg_control to pass vhost zerocopy ubuf info to skb */ + if (zcopy_used) { + struct ubuf_info *ubuf; + ubuf = nvq->ubuf_info + nvq->upend_idx; + + vq->heads[nvq->upend_idx].id = cpu_to_vhost32(vq, head); + vq->heads[nvq->upend_idx].len = VHOST_DMA_IN_PROGRESS; + ubuf->callback = vhost_zerocopy_callback; + ubuf->ctx = nvq->ubufs; + ubuf->desc = nvq->upend_idx; + msg.msg_control = ubuf; + msg.msg_controllen = sizeof(ubuf); + ubufs = nvq->ubufs; + atomic_inc(&ubufs->refcount); + nvq->upend_idx = (nvq->upend_idx + 1) % UIO_MAXIOV; + } else { + msg.msg_control = NULL; + ubufs = NULL; + } + /* TODO: Check specific error and bomb out unless ENOBUFS? */ + err = sock->ops->sendmsg(sock, &msg, len); + if (unlikely(err < 0)) { + if (zcopy_used) { + vhost_net_ubuf_put(ubufs); + nvq->upend_idx = ((unsigned)nvq->upend_idx - 1) + % UIO_MAXIOV; + } + vhost_discard_vq_desc(vq, 1); + break; + } + if (err != len) + pr_debug("Truncated TX packet: " + " len %d != %zd\n", err, len); + if (!zcopy_used) + vhost_add_used_and_signal(&net->dev, vq, head, 0); + else + vhost_zerocopy_signal_used(net, vq); + total_len += len; + vhost_net_tx_packet(net); + if (unlikely(total_len >= VHOST_NET_WEIGHT)) { + vhost_poll_queue(&vq->poll); + break; + } + } +out: + mutex_unlock(&vq->mutex); +} + +static int peek_head_len(struct sock *sk) +{ + struct sk_buff *head; + int len = 0; + unsigned long flags; + + spin_lock_irqsave(&sk->sk_receive_queue.lock, flags); + head = skb_peek(&sk->sk_receive_queue); + if (likely(head)) { + len = head->len; + if (skb_vlan_tag_present(head)) + len += VLAN_HLEN; + } + + spin_unlock_irqrestore(&sk->sk_receive_queue.lock, flags); + return len; +} + +/* This is a multi-buffer version of vhost_get_desc, that works if + * vq has read descriptors only. + * @vq - the relevant virtqueue + * @datalen - data length we'll be reading + * @iovcount - returned count of io vectors we fill + * @log - vhost log + * @log_num - log offset + * @quota - headcount quota, 1 for big buffer + * returns number of buffer heads allocated, negative on error + */ +static int get_rx_bufs(struct vhost_virtqueue *vq, + struct vring_used_elem *heads, + int datalen, + unsigned *iovcount, + struct vhost_log *log, + unsigned *log_num, + unsigned int quota) +{ + unsigned int out, in; + int seg = 0; + int headcount = 0; + unsigned d; + int r, nlogs = 0; + /* len is always initialized before use since we are always called with + * datalen > 0. + */ + u32 uninitialized_var(len); + + while (datalen > 0 && headcount < quota) { + if (unlikely(seg >= UIO_MAXIOV)) { + r = -ENOBUFS; + goto err; + } + r = vhost_get_vq_desc(vq, vq->iov + seg, + ARRAY_SIZE(vq->iov) - seg, &out, + &in, log, log_num); + if (unlikely(r < 0)) + goto err; + + d = r; + if (d == vq->num) { + r = 0; + goto err; + } + if (unlikely(out || in <= 0)) { + vq_err(vq, "unexpected descriptor format for RX: " + "out %d, in %d\n", out, in); + r = -EINVAL; + goto err; + } + if (unlikely(log)) { + nlogs += *log_num; + log += *log_num; + } + heads[headcount].id = cpu_to_vhost32(vq, d); + len = iov_length(vq->iov + seg, in); + heads[headcount].len = cpu_to_vhost32(vq, len); + datalen -= len; + ++headcount; + seg += in; + } + heads[headcount - 1].len = cpu_to_vhost32(vq, len + datalen); + *iovcount = seg; + if (unlikely(log)) + *log_num = nlogs; + + /* Detect overrun */ + if (unlikely(datalen > 0)) { + r = UIO_MAXIOV + 1; + goto err; + } + return headcount; +err: + vhost_discard_vq_desc(vq, headcount); + return r; +} + +/* 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_net_virtqueue *nvq = &net->vqs[VHOST_NET_VQ_RX]; + struct vhost_virtqueue *vq = &nvq->vq; + unsigned uninitialized_var(in), log; + 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_flags = MSG_DONTWAIT, + }; + struct virtio_net_hdr hdr = { + .flags = 0, + .gso_type = VIRTIO_NET_HDR_GSO_NONE + }; + size_t total_len = 0; + int err, mergeable; + s16 headcount; + size_t vhost_hlen, sock_hlen; + size_t vhost_len, sock_len; + struct socket *sock; + struct iov_iter fixup; + __virtio16 num_buffers; + + mutex_lock(&vq->mutex); + sock = vq->private_data; + if (!sock) + goto out; + vhost_disable_notify(&net->dev, vq); + + vhost_hlen = nvq->vhost_hlen; + sock_hlen = nvq->sock_hlen; + + vq_log = unlikely(vhost_has_feature(vq, VHOST_F_LOG_ALL)) ? + vq->log : NULL; + mergeable = vhost_has_feature(vq, VIRTIO_NET_F_MRG_RXBUF); + + while ((sock_len = peek_head_len(sock->sk))) { + sock_len += sock_hlen; + vhost_len = sock_len + vhost_hlen; + headcount = get_rx_bufs(vq, vq->heads, vhost_len, + &in, vq_log, &log, + likely(mergeable) ? UIO_MAXIOV : 1); + /* On error, stop handling until the next kick. */ + if (unlikely(headcount < 0)) + break; + /* On overrun, truncate and discard */ + if (unlikely(headcount > UIO_MAXIOV)) { + iov_iter_init(&msg.msg_iter, READ, vq->iov, 1, 1); + err = sock->ops->recvmsg(sock, &msg, + 1, MSG_DONTWAIT | MSG_TRUNC); + pr_debug("Discarded rx packet: len %zd\n", sock_len); + continue; + } + /* OK, now we need to know about added descriptors. */ + if (!headcount) { + if (unlikely(vhost_enable_notify(&net->dev, vq))) { + /* They have slipped one in as we were + * doing that: check again. */ + vhost_disable_notify(&net->dev, vq); + continue; + } + /* Nothing new? Wait for eventfd to tell us + * they refilled. */ + break; + } + /* We don't need to be notified again. */ + iov_iter_init(&msg.msg_iter, READ, vq->iov, in, vhost_len); + fixup = msg.msg_iter; + if (unlikely((vhost_hlen))) { + /* We will supply the header ourselves + * TODO: support TSO. + */ + iov_iter_advance(&msg.msg_iter, vhost_hlen); + } + err = sock->ops->recvmsg(sock, &msg, + sock_len, MSG_DONTWAIT | MSG_TRUNC); + /* Userspace might have consumed the packet meanwhile: + * it's not supposed to do this usually, but might be hard + * to prevent. Discard data we got (if any) and keep going. */ + if (unlikely(err != sock_len)) { + pr_debug("Discarded rx packet: " + " len %d, expected %zd\n", err, sock_len); + vhost_discard_vq_desc(vq, headcount); + continue; + } + /* Supply virtio_net_hdr if VHOST_NET_F_VIRTIO_NET_HDR */ + if (unlikely(vhost_hlen)) { + if (copy_to_iter(&hdr, sizeof(hdr), + &fixup) != sizeof(hdr)) { + vq_err(vq, "Unable to write vnet_hdr " + "at addr %p\n", vq->iov->iov_base); + break; + } + } else { + /* Header came from socket; we'll need to patch + * ->num_buffers over if VIRTIO_NET_F_MRG_RXBUF + */ + iov_iter_advance(&fixup, sizeof(hdr)); + } + /* TODO: Should check and handle checksum. */ + + num_buffers = cpu_to_vhost16(vq, headcount); + if (likely(mergeable) && + copy_to_iter(&num_buffers, sizeof num_buffers, + &fixup) != sizeof num_buffers) { + vq_err(vq, "Failed num_buffers write"); + vhost_discard_vq_desc(vq, headcount); + break; + } + vhost_add_used_and_signal_n(&net->dev, vq, vq->heads, + headcount); + if (unlikely(vq_log)) + vhost_log_write(vq, vq_log, log, vhost_len); + total_len += vhost_len; + if (unlikely(total_len >= VHOST_NET_WEIGHT)) { + vhost_poll_queue(&vq->poll); + break; + } + } +out: + mutex_unlock(&vq->mutex); +} + +static void handle_tx_kick(struct vhost_work *work) +{ + struct vhost_virtqueue *vq = container_of(work, struct vhost_virtqueue, + poll.work); + struct vhost_net *net = container_of(vq->dev, struct vhost_net, dev); + + handle_tx(net); +} + +static void handle_rx_kick(struct vhost_work *work) +{ + struct vhost_virtqueue *vq = container_of(work, struct vhost_virtqueue, + poll.work); + struct vhost_net *net = container_of(vq->dev, struct vhost_net, dev); + + handle_rx(net); +} + +static void handle_tx_net(struct vhost_work *work) +{ + struct vhost_net *net = container_of(work, struct vhost_net, + poll[VHOST_NET_VQ_TX].work); + handle_tx(net); +} + +static void handle_rx_net(struct vhost_work *work) +{ + struct vhost_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; + struct vhost_dev *dev; + struct vhost_virtqueue **vqs; + int i; + + n = kmalloc(sizeof *n, GFP_KERNEL | __GFP_NOWARN | __GFP_REPEAT); + if (!n) { + n = vmalloc(sizeof *n); + if (!n) + return -ENOMEM; + } + vqs = kmalloc(VHOST_NET_VQ_MAX * sizeof(*vqs), GFP_KERNEL); + if (!vqs) { + kvfree(n); + return -ENOMEM; + } + + dev = &n->dev; + vqs[VHOST_NET_VQ_TX] = &n->vqs[VHOST_NET_VQ_TX].vq; + vqs[VHOST_NET_VQ_RX] = &n->vqs[VHOST_NET_VQ_RX].vq; + n->vqs[VHOST_NET_VQ_TX].vq.handle_kick = handle_tx_kick; + n->vqs[VHOST_NET_VQ_RX].vq.handle_kick = handle_rx_kick; + for (i = 0; i < VHOST_NET_VQ_MAX; i++) { + n->vqs[i].ubufs = NULL; + n->vqs[i].ubuf_info = NULL; + n->vqs[i].upend_idx = 0; + n->vqs[i].done_idx = 0; + n->vqs[i].vhost_hlen = 0; + n->vqs[i].sock_hlen = 0; + } + vhost_dev_init(dev, vqs, VHOST_NET_VQ_MAX); + + vhost_poll_init(n->poll + VHOST_NET_VQ_TX, handle_tx_net, POLLOUT, dev); + vhost_poll_init(n->poll + VHOST_NET_VQ_RX, handle_rx_net, POLLIN, dev); + + f->private_data = n; + + return 0; +} + +static void vhost_net_disable_vq(struct vhost_net *n, + struct vhost_virtqueue *vq) +{ + struct vhost_net_virtqueue *nvq = + container_of(vq, struct vhost_net_virtqueue, vq); + struct vhost_poll *poll = n->poll + (nvq - n->vqs); + if (!vq->private_data) + return; + vhost_poll_stop(poll); +} + +static int vhost_net_enable_vq(struct vhost_net *n, + struct vhost_virtqueue *vq) +{ + struct vhost_net_virtqueue *nvq = + container_of(vq, struct vhost_net_virtqueue, vq); + struct vhost_poll *poll = n->poll + (nvq - n->vqs); + struct socket *sock; + + sock = vq->private_data; + if (!sock) + return 0; + + return vhost_poll_start(poll, 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); + 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].vq); + *rx_sock = vhost_net_stop_vq(n, &n->vqs[VHOST_NET_VQ_RX].vq); +} + +static void vhost_net_flush_vq(struct vhost_net *n, int index) +{ + vhost_poll_flush(n->poll + index); + vhost_poll_flush(&n->vqs[index].vq.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); + if (n->vqs[VHOST_NET_VQ_TX].ubufs) { + mutex_lock(&n->vqs[VHOST_NET_VQ_TX].vq.mutex); + n->tx_flush = true; + mutex_unlock(&n->vqs[VHOST_NET_VQ_TX].vq.mutex); + /* Wait for all lower device DMAs done. */ + vhost_net_ubuf_put_and_wait(n->vqs[VHOST_NET_VQ_TX].ubufs); + mutex_lock(&n->vqs[VHOST_NET_VQ_TX].vq.mutex); + n->tx_flush = false; + atomic_set(&n->vqs[VHOST_NET_VQ_TX].ubufs->refcount, 1); + mutex_unlock(&n->vqs[VHOST_NET_VQ_TX].vq.mutex); + } +} + +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_stop(&n->dev); + vhost_dev_cleanup(&n->dev, false); + vhost_net_vq_reset(n); + if (tx_sock) + sockfd_put(tx_sock); + if (rx_sock) + sockfd_put(rx_sock); + /* Make sure no callbacks are outstanding */ + synchronize_rcu_bh(); + /* We do an extra flush before freeing memory, + * since jobs can re-queue themselves. */ + vhost_net_flush(n); + kfree(n->dev.vqs); + kvfree(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: + sockfd_put(sock); + 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; + struct vhost_net_virtqueue *nvq; + struct vhost_net_ubuf_ref *ubufs, *oldubufs = NULL; + 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].vq; + nvq = &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) { + ubufs = vhost_net_ubuf_alloc(vq, + sock && vhost_sock_zcopy(sock)); + if (IS_ERR(ubufs)) { + r = PTR_ERR(ubufs); + goto err_ubufs; + } + + vhost_net_disable_vq(n, vq); + vq->private_data = sock; + r = vhost_init_used(vq); + if (r) + goto err_used; + r = vhost_net_enable_vq(n, vq); + if (r) + goto err_used; + + oldubufs = nvq->ubufs; + nvq->ubufs = ubufs; + + n->tx_packets = 0; + n->tx_zcopy_err = 0; + n->tx_flush = false; + } + + mutex_unlock(&vq->mutex); + + if (oldubufs) { + vhost_net_ubuf_put_wait_and_free(oldubufs); + mutex_lock(&vq->mutex); + vhost_zerocopy_signal_used(n, vq); + mutex_unlock(&vq->mutex); + } + + if (oldsock) { + vhost_net_flush_vq(n, index); + sockfd_put(oldsock); + } + + mutex_unlock(&n->dev.mutex); + return 0; + +err_used: + vq->private_data = oldsock; + vhost_net_enable_vq(n, vq); + if (ubufs) + vhost_net_ubuf_put_wait_and_free(ubufs); +err_ubufs: + sockfd_put(sock); +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; + struct vhost_memory *memory; + + mutex_lock(&n->dev.mutex); + err = vhost_dev_check_owner(&n->dev); + if (err) + goto done; + memory = vhost_dev_reset_owner_prepare(); + if (!memory) { + err = -ENOMEM; + goto done; + } + vhost_net_stop(n, &tx_sock, &rx_sock); + vhost_net_flush(n); + vhost_dev_reset_owner(&n->dev, memory); + vhost_net_vq_reset(n); +done: + mutex_unlock(&n->dev.mutex); + if (tx_sock) + sockfd_put(tx_sock); + if (rx_sock) + sockfd_put(rx_sock); + return err; +} + +static int vhost_net_set_features(struct vhost_net *n, u64 features) +{ + size_t vhost_hlen, sock_hlen, hdr_len; + int i; + + hdr_len = (features & ((1ULL << VIRTIO_NET_F_MRG_RXBUF) | + (1ULL << VIRTIO_F_VERSION_1))) ? + sizeof(struct virtio_net_hdr_mrg_rxbuf) : + sizeof(struct virtio_net_hdr); + if (features & (1 << VHOST_NET_F_VIRTIO_NET_HDR)) { + /* vhost provides vnet_hdr */ + vhost_hlen = hdr_len; + sock_hlen = 0; + } else { + /* socket provides vnet_hdr */ + vhost_hlen = 0; + sock_hlen = hdr_len; + } + 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; + } + for (i = 0; i < VHOST_NET_VQ_MAX; ++i) { + mutex_lock(&n->vqs[i].vq.mutex); + n->vqs[i].vq.acked_features = features; + n->vqs[i].vhost_hlen = vhost_hlen; + n->vqs[i].sock_hlen = sock_hlen; + mutex_unlock(&n->vqs[i].vq.mutex); + } + mutex_unlock(&n->dev.mutex); + return 0; +} + +static long vhost_net_set_owner(struct vhost_net *n) +{ + int r; + + mutex_lock(&n->dev.mutex); + if (vhost_dev_has_owner(&n->dev)) { + r = -EBUSY; + goto out; + } + r = vhost_net_set_ubuf_info(n); + if (r) + goto out; + r = vhost_dev_set_owner(&n->dev); + if (r) + vhost_net_clear_ubuf_info(n); + vhost_net_flush(n); +out: + mutex_unlock(&n->dev.mutex); + return r; +} + +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: + if (copy_from_user(&backend, argp, sizeof backend)) + return -EFAULT; + return vhost_net_set_backend(n, backend.index, backend.fd); + case VHOST_GET_FEATURES: + features = VHOST_NET_FEATURES; + if (copy_to_user(featurep, &features, sizeof features)) + return -EFAULT; + return 0; + case VHOST_SET_FEATURES: + if (copy_from_user(&features, featurep, sizeof features)) + return -EFAULT; + if (features & ~VHOST_NET_FEATURES) + return -EOPNOTSUPP; + return vhost_net_set_features(n, features); + case VHOST_RESET_OWNER: + return vhost_net_reset_owner(n); + case VHOST_SET_OWNER: + return vhost_net_set_owner(n); + default: + mutex_lock(&n->dev.mutex); + r = vhost_dev_ioctl(&n->dev, ioctl, argp); + if (r == -ENOIOCTLCMD) + r = vhost_vring_ioctl(&n->dev, ioctl, argp); + else + 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 + +static const 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, + .llseek = noop_llseek, +}; + +static struct miscdevice vhost_net_misc = { + .minor = VHOST_NET_MINOR, + .name = "vhost-net", + .fops = &vhost_net_fops, +}; + +static int vhost_net_init(void) +{ + if (experimental_zcopytx) + vhost_net_enable_zcopy(VHOST_NET_VQ_TX); + return misc_register(&vhost_net_misc); +} +module_init(vhost_net_init); + +static void vhost_net_exit(void) +{ + misc_deregister(&vhost_net_misc); +} +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"); +MODULE_ALIAS_MISCDEV(VHOST_NET_MINOR); +MODULE_ALIAS("devname:vhost-net"); |