--- /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/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");
Code Review / kvmfornfv.git / blobdiff