@@ -5619,6 +5619,15 @@ S: Maintained
F: Documentation/filesystems/vfat.txt
F: fs/fat/
+VIRTIO HOST (VHOST)
+M: "Michael S. Tsirkin" <mst@redhat.com>
+L: kvm@vger.kernel.org
+L: virtualization@lists.osdl.org
+L: netdev@vger.kernel.org
+S: Maintained
+F: drivers/vhost/
+F: include/linux/vhost.h
+
VIA RHINE NETWORK DRIVER
M: Roger Luethi <rl@hellgate.ch>
S: Maintained
@@ -64,6 +64,7 @@ config KVM_AMD
# OK, it's a little counter-intuitive to do this, but it puts it neatly under
# the virtualization menu.
+source drivers/vhost/Kconfig
source drivers/lguest/Kconfig
source drivers/virtio/Kconfig
@@ -106,6 +106,7 @@ obj-$(CONFIG_HID) += hid/
obj-$(CONFIG_PPC_PS3) += ps3/
obj-$(CONFIG_OF) += of/
obj-$(CONFIG_SSB) += ssb/
+obj-$(CONFIG_VHOST_NET) += vhost/
obj-$(CONFIG_VIRTIO) += virtio/
obj-$(CONFIG_VLYNQ) += vlynq/
obj-$(CONFIG_STAGING) += staging/
new file mode 100644
@@ -0,0 +1,11 @@
+config VHOST_NET
+ tristate "Host kernel accelerator for virtio net"
+ depends on NET && EVENTFD
+ ---help---
+ This kernel module can be loaded in host kernel to accelerate
+ guest networking with virtio_net. Not to be confused with virtio_net
+ module itself which needs to be loaded in guest kernel.
+
+ To compile this driver as a module, choose M here: the module will
+ be called vhost_net.
+
new file mode 100644
@@ -0,0 +1,2 @@
+obj-$(CONFIG_VHOST_NET) += vhost_net.o
+vhost_net-y := vhost.o net.o
new file mode 100644
@@ -0,0 +1,633 @@
+/* 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_no_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, &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 (vhost_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: "
+ "%ld 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_trigger(&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_no_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, &out, &in,
+ vq_log, &log);
+ /* OK, now we need to know about added descriptors. */
+ if (head == vq->num && vhost_notify(vq))
+ /* They could have slipped one in as we were doing that:
+ * check again. */
+ continue;
+ /* Nothing new? Wait for eventfd to tell us they refilled. */
+ if (head == vq->num)
+ break;
+ /* We don't need to be notified again. */
+ vhost_no_notify(vq);
+ 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_trigger(&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 = kzalloc(sizeof *n, GFP_KERNEL);
+ int r;
+ if (!n)
+ return -ENOMEM;
+ f->private_data = n;
+ 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;
+ return 0;
+}
+
+static void vhost_net_disable_vq(struct vhost_net *n, int index)
+{
+ if (!n->vqs[index].private_data)
+ return;
+ if (index == 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, int index)
+{
+ struct socket *sock = n->vqs[index].private_data;
+ if (!sock)
+ return;
+ if (index == 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, int index)
+{
+ struct socket *sock;
+
+ mutex_lock(&n->vqs[index].mutex);
+ sock = n->vqs[index].private_data;
+ vhost_net_disable_vq(n, index);
+ rcu_assign_pointer(n->vqs[index].private_data, NULL);
+ mutex_unlock(&n->vqs[index].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, VHOST_NET_VQ_TX);
+ *rx_sock = vhost_net_stop_vq(n, 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;
+ 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 = NULL;
+ struct vhost_virtqueue *vq;
+ int r;
+
+ mutex_lock(&n->dev.mutex);
+ r = vhost_dev_check_owner(&n->dev);
+ if (r)
+ goto done;
+
+ if (index >= VHOST_NET_VQ_MAX) {
+ r = -ENOBUFS;
+ goto done;
+ }
+ vq = n->vqs + index;
+ mutex_lock(&vq->mutex);
+ sock = get_socket(fd);
+ if (IS_ERR(sock)) {
+ r = PTR_ERR(sock);
+ goto done;
+ }
+
+ /* start polling new socket */
+ oldsock = vq->private_data;
+ if (sock == oldsock)
+ goto done;
+
+ vhost_net_disable_vq(n, index);
+ rcu_assign_pointer(vq->private_data, sock);
+ vhost_net_enable_vq(n, index);
+ mutex_unlock(&vq->mutex);
+done:
+ mutex_unlock(&n->dev.mutex);
+ if (oldsock) {
+ vhost_net_flush_vq(n, index);
+ fput(oldsock->file);
+ }
+ return r;
+}
+
+static long vhost_net_reset_owner(struct vhost_net *n)
+{
+ struct socket *tx_sock = NULL;
+ struct socket *rx_sock = NULL;
+ long r;
+ mutex_lock(&n->dev.mutex);
+ r = vhost_dev_check_owner(&n->dev);
+ if (r)
+ goto done;
+ vhost_net_stop(n, &tx_sock, &rx_sock);
+ vhost_net_flush(n);
+ r = 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 r;
+}
+
+static void 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_unlock(&n->dev.mutex);
+ 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);
+ }
+ mutex_unlock(&n->dev.mutex);
+ vhost_net_flush(n);
+}
+
+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;
+ u32 __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 put_user(features, featurep);
+ case VHOST_ACK_FEATURES:
+ r = get_user(features, featurep);
+ /* No features for now */
+ if (r < 0)
+ return r;
+ if (features & ~VHOST_FEATURES)
+ return -EOPNOTSUPP;
+ vhost_net_set_features(n, features);
+ return 0;
+ case VHOST_RESET_OWNER:
+ return vhost_net_reset_owner(n);
+ default:
+ r = vhost_dev_ioctl(&n->dev, ioctl, arg);
+ vhost_net_flush(n);
+ 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");
new file mode 100644
@@ -0,0 +1,970 @@
+/* Copyright (C) 2009 Red Hat, Inc.
+ * Copyright (C) 2006 Rusty Russell IBM Corporation
+ *
+ * Author: Michael S. Tsirkin <mst@redhat.com>
+ *
+ * Inspiration, some code, and most witty comments come from
+ * Documentation/lguest/lguest.c, by Rusty Russell
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2.
+ *
+ * Generic code for virtio server in host kernel.
+ */
+
+#include <linux/eventfd.h>
+#include <linux/vhost.h>
+#include <linux/virtio_net.h>
+#include <linux/mm.h>
+#include <linux/miscdevice.h>
+#include <linux/mutex.h>
+#include <linux/workqueue.h>
+#include <linux/rcupdate.h>
+#include <linux/poll.h>
+#include <linux/file.h>
+#include <linux/highmem.h>
+
+#include <linux/net.h>
+#include <linux/if_packet.h>
+#include <linux/if_arp.h>
+
+#include <net/sock.h>
+
+#include "vhost.h"
+
+enum {
+ VHOST_MEMORY_MAX_NREGIONS = 64,
+ VHOST_MEMORY_F_LOG = 0x1,
+};
+
+static struct workqueue_struct *vhost_workqueue;
+
+static void vhost_poll_func(struct file *file, wait_queue_head_t *wqh,
+ poll_table *pt)
+{
+ struct vhost_poll *poll;
+ poll = container_of(pt, struct vhost_poll, table);
+
+ poll->wqh = wqh;
+ add_wait_queue(wqh, &poll->wait);
+}
+
+static int vhost_poll_wakeup(wait_queue_t *wait, unsigned mode, int sync,
+ void *key)
+{
+ struct vhost_poll *poll;
+ poll = container_of(wait, struct vhost_poll, wait);
+ if (!((unsigned long)key & poll->mask))
+ return 0;
+
+ queue_work(vhost_workqueue, &poll->work);
+ return 0;
+}
+
+/* Init poll structure */
+void vhost_poll_init(struct vhost_poll *poll, work_func_t func,
+ unsigned long mask)
+{
+ INIT_WORK(&poll->work, func);
+ init_waitqueue_func_entry(&poll->wait, vhost_poll_wakeup);
+ init_poll_funcptr(&poll->table, vhost_poll_func);
+ poll->mask = mask;
+}
+
+/* Start polling a file. We add ourselves to file's wait queue. The caller must
+ * keep a reference to a file until after vhost_poll_stop is called. */
+void vhost_poll_start(struct vhost_poll *poll, struct file *file)
+{
+ unsigned long mask;
+ mask = file->f_op->poll(file, &poll->table);
+ if (mask)
+ vhost_poll_wakeup(&poll->wait, 0, 0, (void *)mask);
+}
+
+/* Stop polling a file. After this function returns, it becomes safe to drop the
+ * file reference. You must also flush afterwards. */
+void vhost_poll_stop(struct vhost_poll *poll)
+{
+ remove_wait_queue(poll->wqh, &poll->wait);
+}
+
+/* Flush any work that has been scheduled. When calling this, don't hold any
+ * locks that are also used by the callback. */
+void vhost_poll_flush(struct vhost_poll *poll)
+{
+ flush_work(&poll->work);
+}
+
+void vhost_poll_queue(struct vhost_poll *poll)
+{
+ queue_work(vhost_workqueue, &poll->work);
+}
+
+long vhost_dev_init(struct vhost_dev *dev,
+ struct vhost_virtqueue *vqs, int nvqs)
+{
+ int i;
+ dev->vqs = vqs;
+ dev->nvqs = nvqs;
+ mutex_init(&dev->mutex);
+
+ for (i = 0; i < dev->nvqs; ++i) {
+ dev->vqs[i].dev = dev;
+ mutex_init(&dev->vqs[i].mutex);
+ if (dev->vqs[i].handle_kick)
+ vhost_poll_init(&dev->vqs[i].poll,
+ dev->vqs[i].handle_kick,
+ POLLIN);
+ }
+ return 0;
+}
+
+/* Caller should have device mutex */
+long vhost_dev_check_owner(struct vhost_dev *dev)
+{
+ /* Are you the owner? If not, I don't think you mean to do that */
+ return dev->mm == current->mm ? 0 : -EPERM;
+}
+
+/* Caller should have device mutex */
+static long vhost_dev_set_owner(struct vhost_dev *dev)
+{
+ /* Is there an owner already? */
+ if (dev->mm)
+ return -EBUSY;
+ /* No owner, become one */
+ dev->mm = get_task_mm(current);
+ return 0;
+}
+
+/* Caller should have device mutex */
+long vhost_dev_reset_owner(struct vhost_dev *dev)
+{
+ struct vhost_memory *memory;
+
+ /* Restore memory to default 1:1 mapping. */
+ memory = kzalloc(offsetof(struct vhost_memory, regions) +
+ 2 * sizeof *memory->regions, GFP_KERNEL);
+ if (!memory)
+ return -ENOMEM;
+
+ vhost_dev_cleanup(dev);
+
+ memory->nregions = 2;
+ memory->regions[0].guest_phys_addr = 1;
+ memory->regions[0].userspace_addr = 1;
+ memory->regions[0].memory_size = ~0ULL;
+ memory->regions[1].guest_phys_addr = 0;
+ memory->regions[1].userspace_addr = 0;
+ memory->regions[1].memory_size = 1;
+ dev->memory = memory;
+ return 0;
+}
+
+/* Caller should have device mutex */
+void vhost_dev_cleanup(struct vhost_dev *dev)
+{
+ int i;
+ for (i = 0; i < dev->nvqs; ++i) {
+ if (dev->vqs[i].kick && dev->vqs[i].handle_kick) {
+ vhost_poll_stop(&dev->vqs[i].poll);
+ vhost_poll_flush(&dev->vqs[i].poll);
+ }
+ if (dev->vqs[i].error_ctx)
+ eventfd_ctx_put(dev->vqs[i].error_ctx);
+ if (dev->vqs[i].error)
+ fput(dev->vqs[i].error);
+ if (dev->vqs[i].kick)
+ fput(dev->vqs[i].kick);
+ if (dev->vqs[i].call_ctx)
+ eventfd_ctx_put(dev->vqs[i].call_ctx);
+ if (dev->vqs[i].call)
+ fput(dev->vqs[i].call);
+ dev->vqs[i].error_ctx = NULL;
+ dev->vqs[i].error = NULL;
+ dev->vqs[i].kick = NULL;
+ dev->vqs[i].call_ctx = NULL;
+ dev->vqs[i].call = NULL;
+ }
+ if (dev->log_ctx)
+ eventfd_ctx_put(dev->log_ctx);
+ dev->log_ctx = NULL;
+ if (dev->log_file)
+ fput(dev->log_file);
+ dev->log_file = NULL;
+ /* No one will access memory at this point */
+ kfree(dev->memory);
+ dev->memory = NULL;
+ if (dev->mm)
+ mmput(dev->mm);
+ dev->mm = NULL;
+}
+
+static long vhost_set_memory(struct vhost_dev *d, struct vhost_memory __user *m)
+{
+ struct vhost_memory mem, *newmem, *oldmem;
+ unsigned long size = offsetof(struct vhost_memory, regions);
+ long r;
+ r = copy_from_user(&mem, m, size);
+ if (r)
+ return r;
+ if (mem.padding)
+ return -EOPNOTSUPP;
+ if (mem.nregions > VHOST_MEMORY_MAX_NREGIONS)
+ return -E2BIG;
+ newmem = kmalloc(size + mem.nregions * sizeof *m->regions, GFP_KERNEL);
+ if (!newmem)
+ return -ENOMEM;
+
+ memcpy(newmem, &mem, size);
+ r = copy_from_user(newmem->regions, m->regions,
+ mem.nregions * sizeof *m->regions);
+ if (r) {
+ kfree(newmem);
+ return r;
+ }
+ oldmem = d->memory;
+ rcu_assign_pointer(d->memory, newmem);
+ synchronize_rcu();
+ kfree(oldmem);
+ return 0;
+}
+
+static int init_used(struct vhost_virtqueue *vq)
+{
+ int r = put_user(vq->used_flags, &vq->used->flags);
+ if (r)
+ return r;
+ return get_user(vq->last_used_idx, &vq->used->idx);
+}
+
+static long vhost_set_vring(struct vhost_dev *d, int ioctl, void __user *argp)
+{
+ struct file *eventfp, *filep = NULL,
+ *pollstart = NULL, *pollstop = NULL;
+ struct eventfd_ctx *ctx = NULL;
+ u32 __user *idxp = argp;
+ struct vhost_virtqueue *vq;
+ struct vhost_vring_state s;
+ struct vhost_vring_file f;
+ struct vhost_vring_addr a;
+ u32 idx;
+ long r;
+
+ r = get_user(idx, idxp);
+ if (r < 0)
+ return r;
+ if (idx > d->nvqs)
+ return -ENOBUFS;
+
+ vq = d->vqs + idx;
+
+ mutex_lock(&vq->mutex);
+
+ switch (ioctl) {
+ case VHOST_SET_VRING_NUM:
+ r = copy_from_user(&s, argp, sizeof s);
+ if (r < 0)
+ break;
+ if (s.num > 0xffff) {
+ r = -EINVAL;
+ break;
+ }
+ vq->num = s.num;
+ break;
+ case VHOST_SET_VRING_BASE:
+ r = copy_from_user(&s, argp, sizeof s);
+ if (r < 0)
+ break;
+ if (s.num > 0xffff) {
+ r = -EINVAL;
+ break;
+ }
+ vq->avail_idx = vq->last_avail_idx = s.num;
+ break;
+ case VHOST_GET_VRING_BASE:
+ s.index = idx;
+ s.num = vq->last_avail_idx;
+ r = copy_to_user(argp, &s, sizeof s);
+ break;
+ case VHOST_SET_VRING_DESC:
+ r = copy_from_user(&a, argp, sizeof a);
+ if (r < 0)
+ break;
+ if (a.padding) {
+ r = -EOPNOTSUPP;
+ break;
+ }
+ if ((u64)(unsigned long)a.user_addr != a.user_addr) {
+ r = -EFAULT;
+ break;
+ }
+ vq->desc = (void __user *)(unsigned long)a.user_addr;
+ break;
+ case VHOST_SET_VRING_AVAIL:
+ r = copy_from_user(&a, argp, sizeof a);
+ if (r < 0)
+ break;
+ if (a.padding) {
+ r = -EOPNOTSUPP;
+ break;
+ }
+ if ((u64)(unsigned long)a.user_addr != a.user_addr) {
+ r = -EFAULT;
+ break;
+ }
+ if (a.user_addr & (sizeof *vq->avail->ring - 1)) {
+ r = -EINVAL;
+ break;
+ }
+ vq->avail = (void __user *)(unsigned long)a.user_addr;
+ /* Forget the cached index value. */
+ vq->avail_idx = vq->last_avail_idx;
+ break;
+ case VHOST_SET_VRING_USED:
+ r = copy_from_user(&a, argp, sizeof a);
+ if (r < 0)
+ break;
+ if (a.padding) {
+ r = -EOPNOTSUPP;
+ break;
+ }
+ if ((u64)(unsigned long)a.user_addr != a.user_addr) {
+ r = -EFAULT;
+ break;
+ }
+ if (a.user_addr & (sizeof *vq->used->ring - 1)) {
+ r = -EINVAL;
+ break;
+ }
+ vq->used = (void __user *)(unsigned long)a.user_addr;
+ r = init_used(vq);
+ if (r)
+ break;
+ break;
+ case VHOST_SET_VRING_LOG:
+ r = copy_from_user(&a, argp, sizeof a);
+ if (r < 0)
+ break;
+ if (a.padding) {
+ r = -EOPNOTSUPP;
+ break;
+ }
+ if (a.user_addr == VHOST_VRING_LOG_DISABLE) {
+ vq->log_used = false;
+ break;
+ }
+ if (a.user_addr & (sizeof *vq->used->ring - 1)) {
+ r = -EINVAL;
+ break;
+ }
+ vq->log_used = true;
+ vq->log_addr = a.user_addr;
+ break;
+ case VHOST_SET_VRING_KICK:
+ r = copy_from_user(&f, argp, sizeof f);
+ if (r < 0)
+ break;
+ eventfp = f.fd == -1 ? NULL : eventfd_fget(f.fd);
+ if (IS_ERR(eventfp))
+ return PTR_ERR(eventfp);
+ if (eventfp != vq->kick) {
+ pollstop = filep = vq->kick;
+ pollstart = vq->kick = eventfp;
+ } else
+ filep = eventfp;
+ break;
+ case VHOST_SET_VRING_CALL:
+ r = copy_from_user(&f, argp, sizeof f);
+ if (r < 0)
+ break;
+ eventfp = f.fd == -1 ? NULL : eventfd_fget(f.fd);
+ if (IS_ERR(eventfp))
+ return PTR_ERR(eventfp);
+ if (eventfp != vq->call) {
+ filep = vq->call;
+ ctx = vq->call_ctx;
+ vq->call = eventfp;
+ vq->call_ctx = eventfp ?
+ eventfd_ctx_fileget(eventfp) : NULL;
+ } else
+ filep = eventfp;
+ break;
+ case VHOST_SET_VRING_ERR:
+ r = copy_from_user(&f, argp, sizeof f);
+ if (r < 0)
+ break;
+ eventfp = f.fd == -1 ? NULL : eventfd_fget(f.fd);
+ if (IS_ERR(eventfp))
+ return PTR_ERR(eventfp);
+ if (eventfp != vq->error) {
+ filep = vq->error;
+ vq->error = eventfp;
+ ctx = vq->error_ctx;
+ vq->error_ctx = eventfp ?
+ eventfd_ctx_fileget(eventfp) : NULL;
+ } else
+ filep = eventfp;
+ break;
+ default:
+ r = -ENOIOCTLCMD;
+ }
+
+ if (pollstop && vq->handle_kick)
+ vhost_poll_stop(&vq->poll);
+
+ if (ctx)
+ eventfd_ctx_put(ctx);
+ if (filep)
+ fput(filep);
+
+ if (pollstart && vq->handle_kick)
+ vhost_poll_start(&vq->poll, vq->kick);
+
+ mutex_unlock(&vq->mutex);
+
+ if (pollstop && vq->handle_kick)
+ vhost_poll_flush(&vq->poll);
+ return r;
+}
+
+long vhost_dev_ioctl(struct vhost_dev *d, unsigned int ioctl, unsigned long arg)
+{
+ void __user *argp = (void __user *)arg;
+ struct file *eventfp, *filep = NULL;
+ struct eventfd_ctx *ctx = NULL;
+ u64 p;
+ long r;
+ int i, fd;
+
+ mutex_lock(&d->mutex);
+ /* If you are not the owner, you can become one */
+ if (ioctl == VHOST_SET_OWNER) {
+ r = vhost_dev_set_owner(d);
+ goto done;
+ }
+
+ /* You must be the owner to do anything else */
+ r = vhost_dev_check_owner(d);
+ if (r)
+ goto done;
+
+ switch (ioctl) {
+ case VHOST_SET_MEM_TABLE:
+ r = vhost_set_memory(d, argp);
+ break;
+ case VHOST_SET_LOG_BASE:
+ r = get_user(p, (u64 __user *)argp);
+ if (r < 0)
+ break;
+ if ((u64)(unsigned long)p != p) {
+ r = -EFAULT;
+ break;
+ }
+ for (i = 0; i < d->nvqs; ++i) {
+ mutex_lock(&d->vqs[i].mutex);
+ d->vqs[i].log_base = (void __user *)(unsigned long)p;
+ mutex_unlock(&d->vqs[i].mutex);
+ }
+ break;
+ case VHOST_SET_LOG_FD:
+ r = get_user(fd, (int __user *)argp);
+ if (r < 0)
+ break;
+ eventfp = fd == -1 ? NULL : eventfd_fget(fd);
+ if (IS_ERR(eventfp)) {
+ r = PTR_ERR(eventfp);
+ break;
+ }
+ if (eventfp != d->log_file) {
+ filep = d->log_file;
+ ctx = d->log_ctx;
+ d->log_ctx = eventfp ?
+ eventfd_ctx_fileget(eventfp) : NULL;
+ } else
+ filep = eventfp;
+ for (i = 0; i < d->nvqs; ++i) {
+ mutex_lock(&d->vqs[i].mutex);
+ d->vqs[i].log_ctx = d->log_ctx;
+ mutex_unlock(&d->vqs[i].mutex);
+ }
+ if (ctx)
+ eventfd_ctx_put(ctx);
+ if (filep)
+ fput(filep);
+ break;
+ default:
+ r = vhost_set_vring(d, ioctl, argp);
+ break;
+ }
+done:
+ mutex_unlock(&d->mutex);
+ return r;
+}
+
+static const struct vhost_memory_region *find_region(struct vhost_memory *mem,
+ __u64 addr, __u32 len)
+{
+ struct vhost_memory_region *reg;
+ int i;
+ /* linear search is not brilliant, but we really have on the order of 6
+ * regions in practice */
+ for (i = 0; i < mem->nregions; ++i) {
+ reg = mem->regions + i;
+ if (reg->guest_phys_addr <= addr &&
+ reg->guest_phys_addr + reg->memory_size - 1 >= addr)
+ return reg;
+ }
+ return NULL;
+}
+
+/* TODO: This is really inefficient. We need something like get_user()
+ * (instruction directly accesses the data, with an exception table entry
+ * returning -EFAULT). See Documentation/x86/exception-tables.txt.
+ */
+static int set_bit_to_user(int nr, void __user *addr)
+{
+ unsigned long log = (unsigned long)addr;
+ struct page *page;
+ void *base;
+ int bit = nr + (log % PAGE_SIZE) * 8;
+ int r;
+ r = get_user_pages_fast(log, 1, 1, &page);
+ if (r)
+ return r;
+ base = kmap_atomic(page, KM_USER0);
+ set_bit(bit, base);
+ kunmap_atomic(base, KM_USER0);
+ set_page_dirty_lock(page);
+ put_page(page);
+ return 0;
+}
+
+static int log_write(void __user *log_base,
+ u64 write_address, u64 write_length)
+{
+ int r;
+ if (!write_length)
+ return 0;
+ write_address /= VHOST_PAGE_SIZE;
+ for (;;) {
+ u64 base = (u64)log_base;
+ u64 log = base + write_address / 8;
+ int bit = write_address % 8;
+ if ((u64)(unsigned long)log != log)
+ return -EFAULT;
+ r = set_bit_to_user(bit, (void __user *)log);
+ if (r < 0)
+ return r;
+ if (write_length <= VHOST_PAGE_SIZE)
+ break;
+ write_length -= VHOST_PAGE_SIZE;
+ write_address += VHOST_PAGE_SIZE;
+ }
+ return r;
+}
+
+int vhost_log_write(struct vhost_virtqueue *vq, struct vhost_log *log,
+ unsigned int log_num, u64 len)
+{
+ int i, r;
+
+ /* Make sure data written is seen before log. */
+ wmb();
+ for (i = 0; i < log_num; ++i) {
+ u64 l = min(log[i].len, len);
+ r = log_write(vq->log_base, log[i].addr, l);
+ if (r < 0)
+ return r;
+ len -= l;
+ if (!len)
+ return 0;
+ }
+ if (vq->log_ctx)
+ eventfd_signal(vq->log_ctx, 1);
+ /* Length written exceeds what we have stored. This is a bug. */
+ BUG();
+ return 0;
+}
+
+int translate_desc(struct vhost_dev *dev, u64 addr, u32 len,
+ struct iovec iov[], int iov_size)
+{
+ const struct vhost_memory_region *reg;
+ struct vhost_memory *mem;
+ struct iovec *_iov;
+ u64 s = 0;
+ int ret = 0;
+
+ rcu_read_lock();
+
+ mem = rcu_dereference(dev->memory);
+ while ((u64)len > s) {
+ u64 size;
+ if (ret >= iov_size) {
+ ret = -ENOBUFS;
+ break;
+ }
+ reg = find_region(mem, addr, len);
+ if (!reg) {
+ ret = -EFAULT;
+ break;
+ }
+ _iov = iov + ret;
+ size = reg->memory_size - addr + reg->guest_phys_addr;
+ _iov->iov_len = min((u64)len, size);
+ _iov->iov_base = (void *)
+ (reg->userspace_addr + addr - reg->guest_phys_addr);
+ s += size;
+ addr += size;
+ ++ret;
+ }
+
+ rcu_read_unlock();
+ return ret;
+}
+
+/* Each buffer in the virtqueues is actually a chain of descriptors. This
+ * function returns the next descriptor in the chain,
+ * or -1 if we're at the end. */
+static unsigned next_desc(struct vring_desc *desc)
+{
+ unsigned int next;
+
+ /* If this descriptor says it doesn't chain, we're done. */
+ if (!(desc->flags & VRING_DESC_F_NEXT))
+ return -1;
+
+ /* Check they're not leading us off end of descriptors. */
+ next = desc->next;
+ /* Make sure compiler knows to grab that: we don't want it changing! */
+ /* We will use the result as an index in an array, so most
+ * architectures only need a compiler barrier here. */
+ read_barrier_depends();
+
+ return next;
+}
+
+static unsigned get_indirect(struct vhost_dev *dev, struct vhost_virtqueue *vq,
+ struct iovec iov[],
+ unsigned int *out_num, unsigned int *in_num,
+ struct vhost_log *log, unsigned int *log_num,
+ struct vring_desc *indirect)
+{
+ struct vring_desc desc;
+ unsigned int i = 0, count, found = 0;
+ int ret;
+
+ /* Sanity check */
+ if (indirect->len % sizeof desc) {
+ vq_err(vq, "Invalid length in indirect descriptor: "
+ "len 0x%llx not multiple of 0x%zx\n",
+ (unsigned long long)indirect->len,
+ sizeof desc);
+ return -EINVAL;
+ }
+
+ ret = translate_desc(dev, indirect->addr, indirect->len, vq->indirect,
+ ARRAY_SIZE(vq->indirect));
+ if (ret < 0) {
+ vq_err(vq, "Translation failure %d in indirect.\n", ret);
+ return ret;
+ }
+
+ /* We will use the result as an address to read from, so most
+ * architectures only need a compiler barrier here. */
+ read_barrier_depends();
+
+ count = indirect->len / sizeof desc;
+ /* Buffers are chained via a 16 bit next field, so
+ * we can have at most 2^16 of these. */
+ if (count > USHORT_MAX + 1) {
+ vq_err(vq, "Indirect buffer length too big: %d\n",
+ indirect->len);
+ return -E2BIG;
+ }
+
+ do {
+ unsigned iov_count = *in_num + *out_num;
+ if (++found > count) {
+ vq_err(vq, "Loop detected: last one at %u "
+ "indirect size %u\n",
+ i, count);
+ return -EINVAL;
+ }
+ if (memcpy_fromiovec((unsigned char *)&desc, vq->indirect,
+ sizeof desc)) {
+ vq_err(vq, "Failed indirect descriptor: idx %d, %zx\n",
+ i, (size_t)indirect->addr + i * sizeof desc);
+ return -EINVAL;
+ }
+ if (desc.flags & VRING_DESC_F_INDIRECT) {
+ vq_err(vq, "Nested indirect descriptor: idx %d, %zx\n",
+ i, (size_t)indirect->addr + i * sizeof desc);
+ return -EINVAL;
+ }
+
+ ret = translate_desc(dev, desc.addr, desc.len, iov + iov_count,
+ VHOST_NET_MAX_SG - iov_count);
+ if (ret < 0) {
+ vq_err(vq, "Translation failure %d indirect idx %d\n",
+ ret, i);
+ return ret;
+ }
+ /* If this is an input descriptor, increment that count. */
+ if (desc.flags & VRING_DESC_F_WRITE) {
+ *in_num += ret;
+ if (unlikely(log)) {
+ log[*log_num].addr = desc.addr;
+ log[*log_num].len = desc.len;
+ ++*log_num;
+ }
+ } else {
+ /* If it's an output descriptor, they're all supposed
+ * to come before any input descriptors. */
+ if (*in_num) {
+ vq_err(vq, "Indirect descriptor "
+ "has out after in: idx %d\n", i);
+ return -EINVAL;
+ }
+ *out_num += ret;
+ }
+ } while ((i = next_desc(&desc)) != -1);
+ return 0;
+}
+
+/* This looks in the virtqueue and for the first available buffer, and converts
+ * it to an iovec for convenient access. Since descriptors consist of some
+ * number of output then some number of input descriptors, it's actually two
+ * iovecs, but we pack them into one and note how many of each there were.
+ *
+ * This function returns the descriptor number found, or vq->num (which
+ * is never a valid descriptor number) if none was found. */
+unsigned vhost_get_vq_desc(struct vhost_dev *dev, struct vhost_virtqueue *vq,
+ struct iovec iov[],
+ unsigned int *out_num, unsigned int *in_num,
+ struct vhost_log *log, unsigned int *log_num)
+{
+ struct vring_desc desc;
+ unsigned int i, head, found = 0;
+ u16 last_avail_idx;
+ int ret;
+
+ /* Check it isn't doing very strange things with descriptor numbers. */
+ last_avail_idx = vq->last_avail_idx;
+ if (get_user(vq->avail_idx, &vq->avail->idx)) {
+ vq_err(vq, "Failed to access avail idx at %p\n",
+ &vq->avail->idx);
+ return vq->num;
+ }
+
+ if ((u16)(vq->avail_idx - last_avail_idx) > vq->num) {
+ vq_err(vq, "Guest moved used index from %u to %u",
+ last_avail_idx, vq->avail_idx);
+ return vq->num;
+ }
+
+ /* If there's nothing new since last we looked, return invalid. */
+ if (vq->avail_idx == last_avail_idx)
+ return vq->num;
+
+ /* Only get avail ring entries after they have been exposed by guest. */
+ rmb();
+
+ /* Grab the next descriptor number they're advertising, and increment
+ * the index we've seen. */
+ if (get_user(head, &vq->avail->ring[last_avail_idx % vq->num])) {
+ vq_err(vq, "Failed to read head: idx %d address %p\n",
+ last_avail_idx,
+ &vq->avail->ring[last_avail_idx % vq->num]);
+ return vq->num;
+ }
+
+ /* If their number is silly, that's an error. */
+ if (head >= vq->num) {
+ vq_err(vq, "Guest says index %u > %u is available",
+ head, vq->num);
+ return vq->num;
+ }
+
+ /* When we start there are none of either input nor output. */
+ *out_num = *in_num = 0;
+ if (unlikely(log))
+ *log_num = 0;
+
+ i = head;
+ do {
+ unsigned iov_count = *in_num + *out_num;
+ if (i >= vq->num) {
+ vq_err(vq, "Desc index is %u > %u, head = %u",
+ i, vq->num, head);
+ return vq->num;
+ }
+ if (++found > vq->num) {
+ vq_err(vq, "Loop detected: last one at %u "
+ "vq size %u head %u\n",
+ i, vq->num, head);
+ return vq->num;
+ }
+ ret = copy_from_user(&desc, vq->desc + i, sizeof desc);
+ if (ret) {
+ vq_err(vq, "Failed to get descriptor: idx %d addr %p\n",
+ i, vq->desc + i);
+ return vq->num;
+ }
+ if (desc.flags & VRING_DESC_F_INDIRECT) {
+ ret = get_indirect(dev, vq, iov, out_num, in_num,
+ log, log_num, &desc);
+ if (ret < 0) {
+ vq_err(vq, "Failure detected "
+ "in indirect descriptor at idx %d\n", i);
+ return vq->num;
+ }
+ continue;
+ }
+
+ ret = translate_desc(dev, desc.addr, desc.len, iov + iov_count,
+ VHOST_NET_MAX_SG - iov_count);
+ if (ret < 0) {
+ vq_err(vq, "Translation failure %d descriptor idx %d\n",
+ ret, i);
+ return vq->num;
+ }
+ if (desc.flags & VRING_DESC_F_WRITE) {
+ /* If this is an input descriptor,
+ * increment that count. */
+ *in_num += ret;
+ if (unlikely(log)) {
+ log[*log_num].addr = desc.addr;
+ log[*log_num].len = desc.len;
+ ++*log_num;
+ }
+ } else {
+ /* If it's an output descriptor, they're all supposed
+ * to come before any input descriptors. */
+ if (*in_num) {
+ vq_err(vq, "Descriptor has out after in: "
+ "idx %d\n", i);
+ return vq->num;
+ }
+ *out_num += ret;
+ }
+ } while ((i = next_desc(&desc)) != -1);
+
+ /* On success, increment avail index. */
+ vq->last_avail_idx++;
+ return head;
+}
+
+/* Reverse the effect of vhost_get_vq_desc. Useful for error handling. */
+void vhost_discard_vq_desc(struct vhost_virtqueue *vq)
+{
+ vq->last_avail_idx--;
+}
+
+/* After we've used one of their buffers, we tell them about it. We'll then
+ * want to send them an interrupt, using vq->call. */
+int vhost_add_used(struct vhost_virtqueue *vq,
+ unsigned int head, int len)
+{
+ struct vring_used_elem *used;
+
+ /* The virtqueue contains a ring of used buffers. Get a pointer to the
+ * next entry in that used ring. */
+ used = &vq->used->ring[vq->last_used_idx % vq->num];
+ if (put_user(head, &used->id)) {
+ vq_err(vq, "Failed to write used id");
+ return -EFAULT;
+ }
+ if (put_user(len, &used->len)) {
+ vq_err(vq, "Failed to write used len");
+ return -EFAULT;
+ }
+ /* Make sure buffer is written before we update index. */
+ wmb();
+ if (put_user(vq->last_used_idx + 1, &vq->used->idx)) {
+ vq_err(vq, "Failed to increment used idx");
+ return -EFAULT;
+ }
+ if (unlikely(vq->log_used)) {
+ /* Make sure data is seen before log. */
+ wmb();
+ log_write(vq->log_base, vq->log_addr + sizeof *vq->used->ring *
+ (vq->last_used_idx % vq->num),
+ sizeof *vq->used->ring);
+ log_write(vq->log_base, vq->log_addr, sizeof *vq->used->ring);
+ if (vq->log_ctx)
+ eventfd_signal(vq->log_ctx, 1);
+ }
+ vq->last_used_idx++;
+ return 0;
+}
+
+/* This actually sends the interrupt for this virtqueue */
+void vhost_trigger_irq(struct vhost_dev *dev, struct vhost_virtqueue *vq)
+{
+ __u16 flags = 0;
+ if (get_user(flags, &vq->avail->flags)) {
+ vq_err(vq, "Failed to get flags");
+ return;
+ }
+
+ /* If they don't want an interrupt, don't send one, unless empty. */
+ if ((flags & VRING_AVAIL_F_NO_INTERRUPT) &&
+ (vq->avail_idx != vq->last_avail_idx ||
+ !vhost_has_feature(dev, VIRTIO_F_NOTIFY_ON_EMPTY)))
+ return;
+
+ /* Send the Guest an interrupt tell them we used something up. */
+ if (vq->call_ctx)
+ eventfd_signal(vq->call_ctx, 1);
+}
+
+/* And here's the combo meal deal. Supersize me! */
+void vhost_add_used_and_trigger(struct vhost_dev *dev,
+ struct vhost_virtqueue *vq,
+ unsigned int head, int len)
+{
+ vhost_add_used(vq, head, len);
+ vhost_trigger_irq(dev, vq);
+}
+
+/* OK, now we need to know about added descriptors. */
+bool vhost_notify(struct vhost_virtqueue *vq)
+{
+ int r;
+ if (!(vq->used_flags & VRING_USED_F_NO_NOTIFY))
+ return false;
+ vq->used_flags &= ~VRING_USED_F_NO_NOTIFY;
+ r = put_user(vq->used_flags, &vq->used->flags);
+ if (r)
+ vq_err(vq, "Failed to disable notification: %d\n", r);
+ /* They could have slipped one in as we were doing that: make
+ * sure it's written, tell caller it needs to check again. */
+ mb();
+ return true;
+}
+
+/* We don't need to be notified again. */
+void vhost_no_notify(struct vhost_virtqueue *vq)
+{
+ int r;
+ if (vq->used_flags & VRING_USED_F_NO_NOTIFY)
+ return;
+ vq->used_flags |= VRING_USED_F_NO_NOTIFY;
+ r = put_user(vq->used_flags, &vq->used->flags);
+ if (r)
+ vq_err(vq, "Failed to enable notification: %d\n", r);
+}
+
+int vhost_init(void)
+{
+ vhost_workqueue = create_singlethread_workqueue("vhost");
+ if (!vhost_workqueue)
+ return -ENOMEM;
+ return 0;
+}
+
+void vhost_cleanup(void)
+{
+ destroy_workqueue(vhost_workqueue);
+}
new file mode 100644
@@ -0,0 +1,158 @@
+#ifndef _VHOST_H
+#define _VHOST_H
+
+#include <linux/eventfd.h>
+#include <linux/vhost.h>
+#include <linux/mm.h>
+#include <linux/mutex.h>
+#include <linux/workqueue.h>
+#include <linux/poll.h>
+#include <linux/file.h>
+#include <linux/skbuff.h>
+#include <linux/uio.h>
+#include <linux/virtio_config.h>
+#include <linux/virtio_ring.h>
+
+struct vhost_device;
+
+enum {
+ VHOST_NET_MAX_SG = MAX_SKB_FRAGS + 2,
+};
+
+/* Poll a file (eventfd or socket) */
+/* Note: there's nothing vhost specific about this structure. */
+struct vhost_poll {
+ poll_table table;
+ wait_queue_head_t *wqh;
+ wait_queue_t wait;
+ /* struct which will handle all actual work. */
+ struct work_struct work;
+ unsigned long mask;
+};
+
+void vhost_poll_init(struct vhost_poll *poll, work_func_t func,
+ unsigned long mask);
+void vhost_poll_start(struct vhost_poll *poll, struct file *file);
+void vhost_poll_stop(struct vhost_poll *poll);
+void vhost_poll_flush(struct vhost_poll *poll);
+void vhost_poll_queue(struct vhost_poll *poll);
+
+struct vhost_log {
+ u64 addr;
+ u64 len;
+};
+
+/* The virtqueue structure describes a queue attached to a device. */
+struct vhost_virtqueue {
+ struct vhost_dev *dev;
+
+ /* The actual ring of buffers. */
+ struct mutex mutex;
+ unsigned int num;
+ struct vring_desc __user *desc;
+ struct vring_avail __user *avail;
+ struct vring_used __user *used;
+ struct file *kick;
+ struct file *call;
+ struct file *error;
+ struct eventfd_ctx *call_ctx;
+ struct eventfd_ctx *error_ctx;
+ struct eventfd_ctx *log_ctx;
+
+ struct vhost_poll poll;
+
+ /* The routine to call when the Guest pings us, or timeout. */
+ work_func_t handle_kick;
+
+ /* Last available index we saw. */
+ u16 last_avail_idx;
+
+ /* Caches available index value from user. */
+ u16 avail_idx;
+
+ /* Last index we used. */
+ u16 last_used_idx;
+
+ /* Used flags */
+ u16 used_flags;
+
+ /* Log writes to used structure. */
+ bool log_used;
+ u64 log_addr;
+
+ struct iovec indirect[VHOST_NET_MAX_SG];
+ struct iovec iov[VHOST_NET_MAX_SG];
+ struct iovec hdr[VHOST_NET_MAX_SG];
+ size_t hdr_size;
+ /* We use a kind of RCU to access private pointer.
+ * All readers access it from workqueue, which makes it possible to
+ * flush the workqueue instead of synchronize_rcu. Therefore readers do
+ * not need to call rcu_read_lock/rcu_read_unlock: the beginning of
+ * work item execution acts instead of rcu_read_lock() and the end of
+ * work item execution acts instead of rcu_read_lock().
+ * Writers use virtqueue mutex. */
+ void *private_data;
+ /* Log write descriptors */
+ void __user *log_base;
+ struct vhost_log log[VHOST_NET_MAX_SG];
+};
+
+struct vhost_dev {
+ /* Readers use RCU to access memory table pointer
+ * log base pointer and features.
+ * Writers use mutex below.*/
+ struct vhost_memory *memory;
+ struct mm_struct *mm;
+ struct mutex mutex;
+ unsigned acked_features;
+ struct vhost_virtqueue *vqs;
+ int nvqs;
+ struct file *log_file;
+ struct eventfd_ctx *log_ctx;
+};
+
+long vhost_dev_init(struct vhost_dev *, struct vhost_virtqueue *vqs, int nvqs);
+long vhost_dev_check_owner(struct vhost_dev *);
+long vhost_dev_reset_owner(struct vhost_dev *);
+void vhost_dev_cleanup(struct vhost_dev *);
+long vhost_dev_ioctl(struct vhost_dev *, unsigned int ioctl, unsigned long arg);
+
+unsigned vhost_get_vq_desc(struct vhost_dev *, struct vhost_virtqueue *,
+ struct iovec iov[],
+ unsigned int *out_num, unsigned int *in_num,
+ struct vhost_log *log, unsigned int *log_num);
+void vhost_discard_vq_desc(struct vhost_virtqueue *);
+
+int vhost_add_used(struct vhost_virtqueue *, unsigned int head, int len);
+void vhost_trigger_irq(struct vhost_dev *, struct vhost_virtqueue *);
+void vhost_add_used_and_trigger(struct vhost_dev *, struct vhost_virtqueue *,
+ unsigned int head, int len);
+void vhost_no_notify(struct vhost_virtqueue *);
+bool vhost_notify(struct vhost_virtqueue *);
+
+int vhost_log_write(struct vhost_virtqueue *vq, struct vhost_log *log,
+ unsigned int log_num, u64 len);
+
+int vhost_init(void);
+void vhost_cleanup(void);
+
+#define vq_err(vq, fmt, ...) do { \
+ pr_debug(pr_fmt(fmt), ##__VA_ARGS__); \
+ if ((vq)->error_ctx) \
+ eventfd_signal((vq)->error_ctx, 1);\
+ } while (0)
+
+enum {
+ VHOST_FEATURES = (1 << VIRTIO_F_NOTIFY_ON_EMPTY) |
+ (1 << VIRTIO_RING_F_INDIRECT_DESC) |
+ (1 << VHOST_F_LOG_ALL) |
+ (1 << VHOST_NET_F_VIRTIO_NET_HDR),
+};
+
+static inline int vhost_has_feature(struct vhost_dev *dev, int bit)
+{
+ unsigned acked_features = rcu_dereference(dev->acked_features);
+ return acked_features & (1 << bit);
+}
+
+#endif
@@ -361,6 +361,7 @@ unifdef-y += uio.h
unifdef-y += unistd.h
unifdef-y += usbdevice_fs.h
unifdef-y += utsname.h
+unifdef-y += vhost.h
unifdef-y += videodev2.h
unifdef-y += videodev.h
unifdef-y += virtio_config.h
@@ -30,6 +30,7 @@
#define HPET_MINOR 228
#define FUSE_MINOR 229
#define KVM_MINOR 232
+#define VHOST_NET_MINOR 233
#define MISC_DYNAMIC_MINOR 255
struct device;
new file mode 100644
@@ -0,0 +1,126 @@
+#ifndef _LINUX_VHOST_H
+#define _LINUX_VHOST_H
+/* Userspace interface for in-kernel virtio accelerators. */
+
+/* vhost is used to reduce the number of system calls involved in virtio.
+ *
+ * Existing virtio net code is used in the guest without modification.
+ *
+ * This header includes interface used by userspace hypervisor for
+ * device configuration.
+ */
+
+#include <linux/types.h>
+#include <linux/compiler.h>
+#include <linux/ioctl.h>
+#include <linux/virtio_config.h>
+#include <linux/virtio_ring.h>
+
+struct vhost_vring_state {
+ unsigned int index;
+ unsigned int num;
+};
+
+struct vhost_vring_file {
+ unsigned int index;
+ int fd; /* Pass -1 to unbind from file. */
+
+};
+
+struct vhost_vring_addr {
+ unsigned int index;
+ unsigned int padding;
+ __u64 user_addr;
+};
+
+struct vhost_memory_region {
+ __u64 guest_phys_addr;
+ __u64 memory_size; /* bytes */
+ __u64 userspace_addr;
+ __u64 flags_padding; /* No flags are currently specified. */
+};
+
+/* All region addresses and sizes must be 4K aligned. */
+#define VHOST_PAGE_SIZE 0x1000
+
+struct vhost_memory {
+ __u32 nregions;
+ __u32 padding;
+ struct vhost_memory_region regions[0];
+};
+
+/* ioctls */
+
+#define VHOST_VIRTIO 0xAF
+
+/* Features bitmask for forward compatibility. Transport bits are used for
+ * vhost specific features. */
+#define VHOST_GET_FEATURES _IOR(VHOST_VIRTIO, 0x00, __u64)
+#define VHOST_ACK_FEATURES _IOW(VHOST_VIRTIO, 0x00, __u64)
+
+/* Set current process as the (exclusive) owner of this file descriptor. This
+ * must be called before any other vhost command. Further calls to
+ * VHOST_OWNER_SET fail until VHOST_OWNER_RESET is called. */
+#define VHOST_SET_OWNER _IO(VHOST_VIRTIO, 0x01)
+/* Give up ownership, and reset the device to default values.
+ * Allows subsequent call to VHOST_OWNER_SET to succeed. */
+#define VHOST_RESET_OWNER _IO(VHOST_VIRTIO, 0x02)
+
+/* Set up/modify memory layout */
+#define VHOST_SET_MEM_TABLE _IOW(VHOST_VIRTIO, 0x03, struct vhost_memory)
+
+/* Write logging setup. */
+/* Memory writes can optionally be logged by setting bit at an offset
+ * (calculated from the physical address) from specified log base.
+ * The bit is set using an atomic 32 bit operation. */
+/* Set base address for logging. */
+#define VHOST_SET_LOG_BASE _IOW(VHOST_VIRTIO, 0x04, __u64)
+/* Specify an eventfd file descriptor to signal on log write. */
+#define VHOST_SET_LOG_FD _IOW(VHOST_VIRTIO, 0x07, int)
+
+/* Ring setup. These parameters can not be modified while ring is running
+ * (bound to a device). */
+/* Set number of descriptors in ring */
+#define VHOST_SET_VRING_NUM _IOW(VHOST_VIRTIO, 0x10, struct vhost_vring_state)
+/* Start of array of descriptors (virtually contiguous) */
+#define VHOST_SET_VRING_DESC _IOW(VHOST_VIRTIO, 0x11, struct vhost_vring_addr)
+/* Used structure address. Must be 32 bit aligned */
+#define VHOST_SET_VRING_USED _IOW(VHOST_VIRTIO, 0x12, struct vhost_vring_addr)
+/* Available structure address. Must be 16 bit aligned */
+#define VHOST_SET_VRING_AVAIL _IOW(VHOST_VIRTIO, 0x13, struct vhost_vring_addr)
+/* Base value where queue looks for available descriptors */
+#define VHOST_SET_VRING_BASE _IOW(VHOST_VIRTIO, 0x14, struct vhost_vring_state)
+/* Get accessor: reads index, writes value in num */
+#define VHOST_GET_VRING_BASE _IOWR(VHOST_VIRTIO, 0x14, struct vhost_vring_state)
+
+/* Logging support. Can be modified while ring is running. */
+/* Log writes to used structure, at offset calculated from specified address.
+ * Address must be 32 bit aligned. Pass 0x1 to disable logging. */
+#define VHOST_SET_VRING_LOG _IOW(VHOST_VIRTIO, 0x18, struct vhost_vring_addr)
+#define VHOST_VRING_LOG_DISABLE (0x1)
+
+/* The following ioctls use eventfd file descriptors to signal and poll
+ * for events. */
+
+/* Set eventfd to poll for added buffers */
+#define VHOST_SET_VRING_KICK _IOW(VHOST_VIRTIO, 0x20, struct vhost_vring_file)
+/* Set eventfd to signal when buffers have beed used */
+#define VHOST_SET_VRING_CALL _IOW(VHOST_VIRTIO, 0x21, struct vhost_vring_file)
+/* Set eventfd to signal an error */
+#define VHOST_SET_VRING_ERR _IOW(VHOST_VIRTIO, 0x22, struct vhost_vring_file)
+
+/* VHOST_NET specific defines */
+
+/* Attach virtio net ring to a raw socket, or tap device.
+ * The socket must be already bound to an ethernet device, this device will be
+ * used for transmit. Pass fd -1 to unbind from the socket and the transmit
+ * device. This can be used to stop the ring (e.g. for migration). */
+#define VHOST_NET_SET_BACKEND _IOW(VHOST_VIRTIO, 0x30, struct vhost_vring_file)
+
+/* Feature bits */
+/* Log all write descriptors. Can be changed while device is active. */
+#define VHOST_F_LOG_ALL 26
+/* vhost-net should add virtio_net_hdr for RX, and strip for TX packets. */
+#define VHOST_NET_F_VIRTIO_NET_HDR 27
+
+#endif