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Subject[PATCH v1 1/3] A device for zero-copy based on KVM virtio-net.
Date
From: Xin Xiaohui <xiaohui.xin@intel.com>

Add a device to utilize the vhost-net backend driver for
copy-less data transfer between guest FE and host NIC.
It pins the guest user space to the host memory and
provides proto_ops as sendmsg/recvmsg to vhost-net.

Signed-off-by: Xin Xiaohui <xiaohui.xin@intel.com>
Signed-off-by: Zhao Yu <yzhao81@gmail.com>
Sigend-off-by: Jeff Dike <jdike@c2.user-mode-linux.org>
---
drivers/vhost/Kconfig | 5 +
drivers/vhost/Makefile | 2 +
drivers/vhost/mpassthru.c | 1202 +++++++++++++++++++++++++++++++++++++++++++++
include/linux/mpassthru.h | 29 ++
4 files changed, 1238 insertions(+), 0 deletions(-)
create mode 100644 drivers/vhost/mpassthru.c
create mode 100644 include/linux/mpassthru.h
diff --git a/drivers/vhost/Kconfig b/drivers/vhost/Kconfig
index 9f409f4..ee32a3b 100644
--- a/drivers/vhost/Kconfig
+++ b/drivers/vhost/Kconfig
@@ -9,3 +9,8 @@ config VHOST_NET
To compile this driver as a module, choose M here: the module will
be called vhost_net.

+config VHOST_PASSTHRU
+ tristate "Zerocopy network driver (EXPERIMENTAL)"
+ depends on VHOST_NET
+ ---help---
+ zerocopy network I/O support
diff --git a/drivers/vhost/Makefile b/drivers/vhost/Makefile
index 72dd020..3f79c79 100644
--- a/drivers/vhost/Makefile
+++ b/drivers/vhost/Makefile
@@ -1,2 +1,4 @@
obj-$(CONFIG_VHOST_NET) += vhost_net.o
vhost_net-y := vhost.o net.o
+
+obj-$(CONFIG_VHOST_PASSTHRU) += mpassthru.o
diff --git a/drivers/vhost/mpassthru.c b/drivers/vhost/mpassthru.c
new file mode 100644
index 0000000..744d6cd
--- /dev/null
+++ b/drivers/vhost/mpassthru.c
@@ -0,0 +1,1202 @@
+/*
+ * MPASSTHRU - Mediate passthrough device.
+ * Copyright (C) 2009 ZhaoYu, XinXiaohui, Dike, Jeffery G
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ */
+
+#define DRV_NAME "mpassthru"
+#define DRV_DESCRIPTION "Mediate passthru device driver"
+#define DRV_COPYRIGHT "(C) 2009 ZhaoYu, XinXiaohui, Dike, Jeffery G"
+
+#include <linux/module.h>
+#include <linux/errno.h>
+#include <linux/kernel.h>
+#include <linux/major.h>
+#include <linux/slab.h>
+#include <linux/smp_lock.h>
+#include <linux/poll.h>
+#include <linux/fcntl.h>
+#include <linux/init.h>
+#include <linux/skbuff.h>
+#include <linux/netdevice.h>
+#include <linux/etherdevice.h>
+#include <linux/miscdevice.h>
+#include <linux/ethtool.h>
+#include <linux/rtnetlink.h>
+#include <linux/if.h>
+#include <linux/if_arp.h>
+#include <linux/if_ether.h>
+#include <linux/crc32.h>
+#include <linux/nsproxy.h>
+#include <linux/uaccess.h>
+#include <linux/virtio_net.h>
+#include <linux/mpassthru.h>
+#include <net/net_namespace.h>
+#include <net/netns/generic.h>
+#include <net/rtnetlink.h>
+#include <net/sock.h>
+
+#include <asm/system.h>
+
+#include "vhost.h"
+
+/* Uncomment to enable debugging */
+/* #define MPASSTHRU_DEBUG 1 */
+
+#ifdef MPASSTHRU_DEBUG
+static int debug;
+
+#define DBG if (mp->debug) printk
+#define DBG1 if (debug == 2) printk
+#else
+#define DBG(a...)
+#define DBG1(a...)
+#endif
+
+#define COPY_THRESHOLD (L1_CACHE_BYTES * 4)
+#define COPY_HDR_LEN (L1_CACHE_BYTES < 64 ? 64 : L1_CACHE_BYTES)
+
+struct frag {
+ u16 offset;
+ u16 size;
+};
+
+struct page_ctor {
+ struct list_head readq;
+ int w_len;
+ int r_len;
+ spinlock_t read_lock;
+ atomic_t refcnt;
+ struct kmem_cache *cache;
+ struct net_device *dev;
+ struct mpassthru_port port;
+ void *sendctrl;
+ void *recvctrl;
+};
+
+struct page_info {
+ struct list_head list;
+ int header;
+ /* indicate the actual length of bytes
+ * send/recv in the user space buffers
+ */
+ int total;
+ int offset;
+ struct page *pages[MAX_SKB_FRAGS+1];
+ struct skb_frag_struct frag[MAX_SKB_FRAGS+1];
+ struct sk_buff *skb;
+ struct page_ctor *ctor;
+
+ /* The pointer relayed to skb, to indicate
+ * it's a user space allocated skb or kernel
+ */
+ struct skb_user_page user;
+ struct skb_shared_info ushinfo;
+
+#define INFO_READ 0
+#define INFO_WRITE 1
+ unsigned flags;
+ unsigned pnum;
+
+ /* It's meaningful for receive, means
+ * the max length allowed
+ */
+ size_t len;
+
+ /* The fields after that is for backend
+ * driver, now for vhost-net.
+ */
+ struct vhost_notifier notifier;
+ unsigned int desc_pos;
+ unsigned int log;
+ struct iovec hdr[VHOST_NET_MAX_SG];
+ struct iovec iov[VHOST_NET_MAX_SG];
+ void *ctl;
+};
+
+struct mp_struct {
+ struct mp_file *mfile;
+ struct net_device *dev;
+ struct page_ctor *ctor;
+ struct socket socket;
+
+#ifdef MPASSTHRU_DEBUG
+ int debug;
+#endif
+};
+
+struct mp_file {
+ atomic_t count;
+ struct mp_struct *mp;
+ struct net *net;
+};
+
+struct mp_sock {
+ struct sock sk;
+ struct mp_struct *mp;
+};
+
+static int mp_dev_change_flags(struct net_device *dev, unsigned flags)
+{
+ int ret = 0;
+
+ rtnl_lock();
+ ret = dev_change_flags(dev, flags);
+ rtnl_unlock();
+
+ if (ret < 0)
+ printk(KERN_ERR "failed to change dev state of %s", dev->name);
+
+ return ret;
+}
+
+/* The main function to allocate user space buffers */
+static struct skb_user_page *page_ctor(struct mpassthru_port *port,
+ struct sk_buff *skb, int npages)
+{
+ int i;
+ unsigned long flags;
+ struct page_ctor *ctor;
+ struct page_info *info = NULL;
+
+ ctor = container_of(port, struct page_ctor, port);
+
+ spin_lock_irqsave(&ctor->read_lock, flags);
+ if (!list_empty(&ctor->readq)) {
+ info = list_first_entry(&ctor->readq, struct page_info, list);
+ list_del(&info->list);
+ }
+ spin_unlock_irqrestore(&ctor->read_lock, flags);
+ if (!info)
+ return NULL;
+
+ for (i = 0; i < info->pnum; i++) {
+ get_page(info->pages[i]);
+ info->frag[i].page = info->pages[i];
+ info->frag[i].page_offset = i ? 0 : info->offset;
+ info->frag[i].size = port->npages > 1 ? PAGE_SIZE :
+ port->data_len;
+ }
+ info->skb = skb;
+ info->user.frags = info->frag;
+ info->user.ushinfo = &info->ushinfo;
+ return &info->user;
+}
+
+static struct vhost_notifier *create_vhost_notifier(struct vhost_virtqueue *vq,
+ struct page_info *info, int size);
+
+static void mp_vhost_notifier_dtor(struct vhost_notifier *vnotify)
+{
+ struct page_info *info = (struct page_info *)(vnotify->ctrl);
+ int i;
+
+ for (i = 0; i < info->pnum; i++) {
+ if (info->pages[i])
+ put_page(info->pages[i]);
+ }
+
+ if (info->flags == INFO_READ) {
+ skb_shinfo(info->skb)->destructor_arg = &info->user;
+ info->skb->destructor = NULL;
+ kfree(info->skb);
+ }
+
+ kmem_cache_free(info->ctor->cache, info);
+
+ return;
+}
+
+/* A helper to clean the skb before the kfree_skb() */
+
+static void page_dtor_prepare(struct page_info *info)
+{
+ if (info->flags == INFO_READ)
+ if (info->skb)
+ info->skb->head = NULL;
+}
+
+/* The callback to destruct the user space buffers or skb */
+static void page_dtor(struct skb_user_page *user)
+{
+ struct page_info *info;
+ struct page_ctor *ctor;
+ struct sock *sk;
+ struct sk_buff *skb;
+ struct vhost_notifier *vnotify;
+ struct vhost_virtqueue *vq = NULL;
+ unsigned long flags;
+ int i;
+
+ if (!user)
+ return;
+ info = container_of(user, struct page_info, user);
+ if (!info)
+ return;
+ ctor = info->ctor;
+ skb = info->skb;
+
+ page_dtor_prepare(info);
+
+ /* If the info->total is 0, make it to be reused */
+ if (!info->total) {
+ spin_lock_irqsave(&ctor->read_lock, flags);
+ list_add(&info->list, &ctor->readq);
+ spin_unlock_irqrestore(&ctor->read_lock, flags);
+ return;
+ }
+
+ /* Receive buffers, should be destructed */
+ if (info->flags == INFO_READ) {
+ for (i = 0; info->pages[i]; i++)
+ put_page(info->pages[i]);
+ info->skb = NULL;
+ return;
+ }
+
+ /* For transmit, we should wait for the DMA finish by hardware.
+ * Queue the notifier to wake up the backend driver
+ */
+ vq = (struct vhost_virtqueue *)info->ctl;
+ vnotify = create_vhost_notifier(vq, info, info->total);
+
+ spin_lock_irqsave(&vq->notify_lock, flags);
+ list_add_tail(&vnotify->list, &vq->notifier);
+ spin_unlock_irqrestore(&vq->notify_lock, flags);
+
+ sk = ctor->port.sock->sk;
+ sk->sk_write_space(sk);
+
+ return;
+}
+
+static int page_ctor_attach(struct mp_struct *mp)
+{
+ int rc;
+ struct page_ctor *ctor;
+ struct net_device *dev = mp->dev;
+
+ /* locked by mp_mutex */
+ if (rcu_dereference(mp->ctor))
+ return -EBUSY;
+
+ ctor = kzalloc(sizeof(*ctor), GFP_KERNEL);
+ if (!ctor)
+ return -ENOMEM;
+ rc = netdev_mp_port_prep(dev, &ctor->port);
+ if (rc)
+ goto fail;
+
+ ctor->cache = kmem_cache_create("skb_page_info",
+ sizeof(struct page_info), 0,
+ SLAB_HWCACHE_ALIGN, NULL);
+
+ if (!ctor->cache)
+ goto cache_fail;
+
+ INIT_LIST_HEAD(&ctor->readq);
+ spin_lock_init(&ctor->read_lock);
+
+ ctor->w_len = 0;
+ ctor->r_len = 0;
+
+ dev_hold(dev);
+ ctor->dev = dev;
+ ctor->port.ctor = page_ctor;
+ ctor->port.sock = &mp->socket;
+ atomic_set(&ctor->refcnt, 1);
+
+ rc = netdev_mp_port_attach(dev, &ctor->port);
+ if (rc)
+ goto fail;
+
+ /* locked by mp_mutex */
+ rcu_assign_pointer(mp->ctor, ctor);
+
+ /* XXX:Need we do set_offload here ? */
+
+ return 0;
+
+fail:
+ kmem_cache_destroy(ctor->cache);
+cache_fail:
+ kfree(ctor);
+ dev_put(dev);
+
+ return rc;
+}
+
+
+static inline void get_page_ctor(struct page_ctor *ctor)
+{
+ atomic_inc(&ctor->refcnt);
+}
+
+static inline void put_page_ctor(struct page_ctor *ctor)
+{
+ if (atomic_dec_and_test(&ctor->refcnt))
+ kfree(ctor);
+}
+
+struct page_info *info_dequeue(struct page_ctor *ctor)
+{
+ unsigned long flags;
+ struct page_info *info = NULL;
+ spin_lock_irqsave(&ctor->read_lock, flags);
+ if (!list_empty(&ctor->readq)) {
+ info = list_first_entry(&ctor->readq,
+ struct page_info, list);
+ list_del(&info->list);
+ }
+ spin_unlock_irqrestore(&ctor->read_lock, flags);
+ return info;
+}
+
+static int page_ctor_detach(struct mp_struct *mp)
+{
+ struct page_ctor *ctor;
+ struct page_info *info;
+ int i;
+
+ ctor = rcu_dereference(mp->ctor);
+ if (!ctor)
+ return -ENODEV;
+
+ while ((info = info_dequeue(ctor))) {
+ for (i = 0; i < info->pnum; i++)
+ if (info->pages[i])
+ put_page(info->pages[i]);
+ kmem_cache_free(ctor->cache, info);
+ }
+ kmem_cache_destroy(ctor->cache);
+ netdev_mp_port_detach(ctor->dev);
+ dev_put(ctor->dev);
+
+ /* locked by mp_mutex */
+ rcu_assign_pointer(mp->ctor, NULL);
+ synchronize_rcu();
+
+ put_page_ctor(ctor);
+
+ return 0;
+}
+
+/* For small user space buffers transmit, we don't need to call
+ * get_user_pages().
+ */
+static struct page_info *alloc_small_page_info(struct page_ctor *ctor,
+ int total)
+{
+ struct page_info *info = kmem_cache_zalloc(ctor->cache, GFP_KERNEL);
+
+ if (!info)
+ return NULL;
+ info->total = total;
+ info->user.dtor = page_dtor;
+ info->ctor = ctor;
+ info->flags = INFO_WRITE;
+ return info;
+}
+
+/* The main function to transform the guest user space address
+ * to host kernel address via get_user_pages(). Thus the hardware
+ * can do DMA directly to the user space address.
+ */
+static struct page_info *alloc_page_info(struct page_ctor *ctor,
+ struct iovec *iov, int count, struct frag *frags,
+ int npages, int total)
+{
+ int rc;
+ int i, j, n = 0;
+ int len;
+ unsigned long base;
+ struct page_info *info = kmem_cache_zalloc(ctor->cache, GFP_KERNEL);
+
+ if (!info)
+ return NULL;
+
+ down_read(&current->mm->mmap_sem);
+ for (i = j = 0; i < count; i++) {
+ base = (unsigned long)iov[i].iov_base;
+ len = iov[i].iov_len;
+
+ if (!len)
+ continue;
+ n = ((base & ~PAGE_MASK) + len + ~PAGE_MASK) >> PAGE_SHIFT;
+
+ rc = get_user_pages(current, current->mm, base, n,
+ npages ? 1 : 0, 0, &info->pages[j], NULL);
+ if (rc != n) {
+ up_read(&current->mm->mmap_sem);
+ goto failed;
+ }
+
+ while (n--) {
+ frags[j].offset = base & ~PAGE_MASK;
+ frags[j].size = min_t(int, len,
+ PAGE_SIZE - frags[j].offset);
+ len -= frags[j].size;
+ base += frags[j].size;
+ j++;
+ }
+ }
+ up_read(&current->mm->mmap_sem);
+
+#ifdef CONFIG_HIGHMEM
+ if (npages && !(dev->features & NETIF_F_HIGHDMA)) {
+ for (i = 0; i < j; i++) {
+ if (PageHighMem(info->pages[i]))
+ goto failed;
+ }
+ }
+#endif
+
+ info->total = total;
+ info->user.dtor = page_dtor;
+ info->ctor = ctor;
+ info->pnum = j;
+
+ if (!npages)
+ info->flags = INFO_WRITE;
+ if (info->flags == INFO_READ) {
+ info->user.start = (u8 *)(((unsigned long)
+ (pfn_to_kaddr(page_to_pfn(info->pages[0]))) +
+ frags[0].offset) - NET_IP_ALIGN - NET_SKB_PAD);
+ info->user.size = iov[0].iov_len + NET_IP_ALIGN + NET_SKB_PAD;
+ }
+ return info;
+
+failed:
+ for (i = 0; i < j; i++)
+ put_page(info->pages[i]);
+
+ kmem_cache_free(ctor->cache, info);
+
+ return NULL;
+}
+
+struct page_ctor *mp_rcu_get_ctor(struct page_ctor *ctor)
+{
+ struct page_ctor *_ctor = NULL;
+
+ rcu_read_lock();
+ _ctor = rcu_dereference(ctor);
+
+ if (!_ctor) {
+ DBG(KERN_INFO "Device %s cannot do mediate passthru.\n",
+ ctor->dev->name);
+ rcu_read_unlock();
+ return NULL;
+ }
+ get_page_ctor(_ctor);
+ rcu_read_unlock();
+ return _ctor;
+}
+
+static int mp_sendmsg(struct kiocb *iocb, struct socket *sock,
+ struct msghdr *m, size_t total_len)
+{
+ struct mp_struct *mp = container_of(sock->sk, struct mp_sock, sk)->mp;
+ struct page_ctor *ctor;
+ struct vhost_virtqueue *vq = (struct vhost_virtqueue *)(m->msg_control);
+ struct iovec *iov = m->msg_iov;
+ struct page_info *info = NULL;
+ struct frag frags[MAX_SKB_FRAGS];
+ struct sk_buff *skb;
+ int count = m->msg_iovlen;
+ int total = 0, header, n, i, len, rc;
+ unsigned long base;
+
+ ctor = mp_rcu_get_ctor(mp->ctor);
+ if (!ctor)
+ return -ENODEV;
+
+ ctor->sendctrl = vq;
+
+ total = iov_length(iov, count);
+
+ if (total < ETH_HLEN) {
+ put_page_ctor(ctor);
+ return -EINVAL;
+ }
+
+ if (total <= COPY_THRESHOLD)
+ goto copy;
+
+ n = 0;
+ for (i = 0; i < count; i++) {
+ base = (unsigned long)iov[i].iov_base;
+ len = iov[i].iov_len;
+ if (!len)
+ continue;
+ n += ((base & ~PAGE_MASK) + len + ~PAGE_MASK) >> PAGE_SHIFT;
+ if (n > MAX_SKB_FRAGS) {
+ put_page_ctor(ctor);
+ return -EINVAL;
+ }
+ }
+
+copy:
+ header = total > COPY_THRESHOLD ? COPY_HDR_LEN : total;
+
+ skb = alloc_skb(header + NET_IP_ALIGN, GFP_ATOMIC);
+ if (!skb)
+ goto drop;
+
+ skb_reserve(skb, NET_IP_ALIGN);
+
+ skb_set_network_header(skb, ETH_HLEN);
+
+ memcpy_fromiovec(skb->data, iov, header);
+ skb_put(skb, header);
+ skb->protocol = *((__be16 *)(skb->data) + ETH_ALEN);
+
+ if (header == total) {
+ rc = total;
+ info = alloc_small_page_info(ctor, total);
+ } else {
+ info = alloc_page_info(ctor, iov, count, frags, 0, total);
+ if (info)
+ for (i = 0; info->pages[i]; i++) {
+ skb_add_rx_frag(skb, i, info->pages[i],
+ frags[i].offset, frags[i].size);
+ info->pages[i] = NULL;
+ }
+ }
+ if (info != NULL) {
+ info->desc_pos = vq->head;
+ info->ctl = vq;
+ info->total = total;
+ info->skb = skb;
+ skb_shinfo(skb)->destructor_arg = &info->user;
+ skb->dev = mp->dev;
+ dev_queue_xmit(skb);
+ mp->dev->stats.tx_packets++;
+ mp->dev->stats.tx_bytes += total;
+ put_page_ctor(ctor);
+ return 0;
+ }
+drop:
+ kfree(skb);
+ if (info) {
+ for (i = 0; info->pages[i]; i++)
+ put_page(info->pages[i]);
+ kmem_cache_free(info->ctor->cache, info);
+ }
+ mp->dev->stats.tx_dropped++;
+ put_page_ctor(ctor);
+ return -ENOMEM;
+}
+
+
+static struct vhost_notifier *create_vhost_notifier(struct vhost_virtqueue *vq,
+ struct page_info *info, int size)
+{
+ struct vhost_notifier *vnotify = NULL;
+
+ vnotify = &info->notifier;
+ memset(vnotify, 0, sizeof(struct vhost_notifier));
+ vnotify->vq = vq;
+ vnotify->head = info->desc_pos;
+ vnotify->size = size;
+ vnotify->log = info->log;
+ vnotify->ctrl = (void *)info;
+ vnotify->dtor = mp_vhost_notifier_dtor;
+ return vnotify;
+}
+
+static void mp_recvmsg_notify(struct vhost_virtqueue *vq)
+{
+ struct socket *sock = vq->private_data;
+ struct mp_struct *mp = container_of(sock->sk, struct mp_sock, sk)->mp;
+ struct page_ctor *ctor = NULL;
+ struct sk_buff *skb = NULL;
+ struct page_info *info = NULL;
+ struct ethhdr *eth;
+ struct vhost_notifier *vnotify = NULL;
+ int len, i;
+ unsigned long flags;
+
+ struct virtio_net_hdr hdr = {
+ .flags = 0,
+ .gso_type = VIRTIO_NET_HDR_GSO_NONE
+ };
+
+ ctor = mp_rcu_get_ctor(mp->ctor);
+ if (!ctor)
+ return;
+
+ while ((skb = skb_dequeue(&sock->sk->sk_receive_queue)) != NULL) {
+ if (skb_shinfo(skb)->destructor_arg) {
+ info = container_of(skb_shinfo(skb)->destructor_arg,
+ struct page_info, user);
+ info->skb = skb;
+ if (skb->len > info->len) {
+ mp->dev->stats.rx_dropped++;
+ DBG(KERN_INFO "Discarded truncated rx packet: "
+ " len %d > %zd\n", skb->len, info->len);
+ info->total = skb->len;
+ goto clean;
+ } else {
+ int i;
+ struct skb_shared_info *gshinfo =
+ (struct skb_shared_info *)(&info->ushinfo);
+ struct skb_shared_info *hshinfo =
+ skb_shinfo(skb);
+
+ if (gshinfo->nr_frags < hshinfo->nr_frags)
+ goto clean;
+ eth = eth_hdr(skb);
+ skb_push(skb, ETH_HLEN);
+
+ hdr.hdr_len = skb_headlen(skb);
+ info->total = skb->len;
+
+ for (i = 0; i < gshinfo->nr_frags; i++)
+ gshinfo->frags[i].size = 0;
+ for (i = 0; i < hshinfo->nr_frags; i++)
+ gshinfo->frags[i].size =
+ hshinfo->frags[i].size;
+ memcpy(skb_shinfo(skb), &info->ushinfo,
+ sizeof(struct skb_shared_info));
+ }
+ } else {
+ /* The skb composed with kernel buffers
+ * in case user space buffers are not sufficent.
+ * The case should be rare.
+ */
+ unsigned long flags;
+ int i;
+ struct skb_shared_info *gshinfo = NULL;
+
+ info = NULL;
+
+ spin_lock_irqsave(&ctor->read_lock, flags);
+ if (!list_empty(&ctor->readq)) {
+ info = list_first_entry(&ctor->readq,
+ struct page_info, list);
+ list_del(&info->list);
+ }
+ spin_unlock_irqrestore(&ctor->read_lock, flags);
+ if (!info) {
+ DBG(KERN_INFO "No user buffer avaliable %p\n",
+ skb);
+ skb_queue_head(&sock->sk->sk_receive_queue,
+ skb);
+ break;
+ }
+ info->skb = skb;
+ /* compute the guest skb frags info */
+ gshinfo = (struct skb_shared_info *)(info->user.start +
+ SKB_DATA_ALIGN(info->user.size));
+
+ if (gshinfo->nr_frags < skb_shinfo(skb)->nr_frags)
+ goto clean;
+
+ eth = eth_hdr(skb);
+ skb_push(skb, ETH_HLEN);
+ info->total = skb->len;
+
+ for (i = 0; i < gshinfo->nr_frags; i++)
+ gshinfo->frags[i].size = 0;
+ for (i = 0; i < skb_shinfo(skb)->nr_frags; i++)
+ gshinfo->frags[i].size =
+ skb_shinfo(skb)->frags[i].size;
+ hdr.hdr_len = min_t(int, skb->len,
+ info->iov[1].iov_len);
+ skb_copy_datagram_iovec(skb, 0, info->iov, skb->len);
+ }
+
+ len = memcpy_toiovec(info->hdr, (unsigned char *)&hdr,
+ sizeof hdr);
+ if (len) {
+ DBG(KERN_INFO
+ "Unable to write vnet_hdr at addr %p: %d\n",
+ info->hdr->iov_base, len);
+ goto clean;
+ }
+ vnotify = create_vhost_notifier(vq, info,
+ skb->len + sizeof(hdr));
+
+ spin_lock_irqsave(&vq->notify_lock, flags);
+ list_add_tail(&vnotify->list, &vq->notifier);
+ spin_unlock_irqrestore(&vq->notify_lock, flags);
+ continue;
+
+clean:
+ kfree_skb(skb);
+ for (i = 0; info->pages[i]; i++)
+ put_page(info->pages[i]);
+ kmem_cache_free(ctor->cache, info);
+ }
+ put_page_ctor(ctor);
+ return;
+}
+
+static int mp_recvmsg(struct kiocb *iocb, struct socket *sock,
+ struct msghdr *m, size_t total_len,
+ int flags)
+{
+ struct mp_struct *mp = container_of(sock->sk, struct mp_sock, sk)->mp;
+ struct page_ctor *ctor;
+ struct vhost_virtqueue *vq = (struct vhost_virtqueue *)(m->msg_control);
+ struct iovec *iov = m->msg_iov;
+ int count = m->msg_iovlen;
+ int npages, payload;
+ struct page_info *info;
+ struct frag frags[MAX_SKB_FRAGS];
+ unsigned long base;
+ int i, len;
+ unsigned long flag;
+
+ if (!(flags & MSG_DONTWAIT))
+ return -EINVAL;
+
+ ctor = mp_rcu_get_ctor(mp->ctor);
+ if (!ctor)
+ return -EINVAL;
+
+ ctor->recvctrl = vq;
+
+ /* Error detections in case invalid user space buffer */
+ if (count > 2 && iov[1].iov_len < ctor->port.hdr_len &&
+ mp->dev->features & NETIF_F_SG) {
+ put_page_ctor(ctor);
+ return -EINVAL;
+ }
+
+ npages = ctor->port.npages;
+ payload = ctor->port.data_len;
+
+ /* If KVM guest virtio-net FE driver use SG feature */
+ if (count > 2) {
+ for (i = 2; i < count; i++) {
+ base = (unsigned long)iov[i].iov_base & ~PAGE_MASK;
+ len = iov[i].iov_len;
+ if (npages == 1)
+ len = min_t(int, len, PAGE_SIZE - base);
+ else if (base)
+ break;
+ payload -= len;
+ if (payload <= 0)
+ goto proceed;
+ if (npages == 1 || (len & ~PAGE_MASK))
+ break;
+ }
+ }
+
+ if ((((unsigned long)iov[1].iov_base & ~PAGE_MASK)
+ - NET_SKB_PAD - NET_IP_ALIGN) >= 0)
+ goto proceed;
+
+ put_page_ctor(ctor);
+ return -EINVAL;
+
+proceed:
+ /* skip the virtnet head */
+ iov++;
+ count--;
+
+ /* Translate address to kernel */
+ info = alloc_page_info(ctor, iov, count, frags, npages, 0);
+ if (!info) {
+ put_page_ctor(ctor);
+ return -ENOMEM;
+ }
+
+ info->len = total_len;
+ info->hdr[0].iov_base = vq->hdr[0].iov_base;
+ info->hdr[0].iov_len = vq->hdr[0].iov_len;
+ info->offset = frags[0].offset;
+ info->desc_pos = vq->head;
+ info->log = vq->_log;
+ info->ctl = NULL;
+
+ iov--;
+ count++;
+
+ memcpy(info->iov, vq->iov, sizeof(struct iovec) * count);
+
+ spin_lock_irqsave(&ctor->read_lock, flag);
+ list_add_tail(&info->list, &ctor->readq);
+ spin_unlock_irqrestore(&ctor->read_lock, flag);
+
+ if (!vq->receiver)
+ vq->receiver = mp_recvmsg_notify;
+
+ put_page_ctor(ctor);
+ return 0;
+}
+
+static void mp_put(struct mp_file *mfile);
+
+static int mp_release(struct socket *sock)
+{
+ struct mp_struct *mp = container_of(sock->sk, struct mp_sock, sk)->mp;
+ struct mp_file *mfile = mp->mfile;
+
+ mp_put(mfile);
+ sock_put(mp->socket.sk);
+ put_net(mfile->net);
+
+ return 0;
+}
+
+/* Ops structure to mimic raw sockets with mp device */
+static const struct proto_ops mp_socket_ops = {
+ .sendmsg = mp_sendmsg,
+ .recvmsg = mp_recvmsg,
+ .release = mp_release,
+};
+
+static struct proto mp_proto = {
+ .name = "mp",
+ .owner = THIS_MODULE,
+ .obj_size = sizeof(struct mp_sock),
+};
+
+static int mp_chr_open(struct inode *inode, struct file * file)
+{
+ struct mp_file *mfile;
+ cycle_kernel_lock();
+ DBG1(KERN_INFO "mp: mp_chr_open\n");
+
+ mfile = kzalloc(sizeof(*mfile), GFP_KERNEL);
+ if (!mfile)
+ return -ENOMEM;
+ atomic_set(&mfile->count, 0);
+ mfile->mp = NULL;
+ mfile->net = get_net(current->nsproxy->net_ns);
+ file->private_data = mfile;
+ return 0;
+}
+
+static void __mp_detach(struct mp_struct *mp)
+{
+ mp->mfile = NULL;
+
+ mp_dev_change_flags(mp->dev, mp->dev->flags & ~IFF_UP);
+ page_ctor_detach(mp);
+ mp_dev_change_flags(mp->dev, mp->dev->flags | IFF_UP);
+
+ /* Drop the extra count on the net device */
+ dev_put(mp->dev);
+}
+
+static DEFINE_MUTEX(mp_mutex);
+
+static void mp_detach(struct mp_struct *mp)
+{
+ mutex_lock(&mp_mutex);
+ __mp_detach(mp);
+ mutex_unlock(&mp_mutex);
+}
+
+static struct mp_struct *mp_get(struct mp_file *mfile)
+{
+ struct mp_struct *mp = NULL;
+ if (atomic_inc_not_zero(&mfile->count))
+ mp = mfile->mp;
+
+ return mp;
+}
+
+static void mp_put(struct mp_file *mfile)
+{
+ if (atomic_dec_and_test(&mfile->count))
+ mp_detach(mfile->mp);
+}
+
+static int mp_attach(struct mp_struct *mp, struct file *file)
+{
+ struct mp_file *mfile = file->private_data;
+ int err;
+
+ netif_tx_lock_bh(mp->dev);
+
+ err = -EINVAL;
+
+ if (mfile->mp)
+ goto out;
+
+ err = -EBUSY;
+ if (mp->mfile)
+ goto out;
+
+ err = 0;
+ mfile->mp = mp;
+ mp->mfile = mfile;
+ mp->socket.file = file;
+ dev_hold(mp->dev);
+ sock_hold(mp->socket.sk);
+ atomic_inc(&mfile->count);
+
+out:
+ netif_tx_unlock_bh(mp->dev);
+ return err;
+}
+
+static void mp_sock_destruct(struct sock *sk)
+{
+ struct mp_struct *mp = container_of(sk, struct mp_sock, sk)->mp;
+ kfree(mp);
+}
+
+static int do_unbind(struct mp_file *mfile)
+{
+ struct mp_struct *mp = mp_get(mfile);
+
+ if (!mp)
+ return -EINVAL;
+
+ mp_detach(mp);
+ sock_put(mp->socket.sk);
+ mp_put(mfile);
+ return 0;
+}
+
+static void mp_sock_data_ready(struct sock *sk, int len)
+{
+ if (sk_has_sleeper(sk))
+ wake_up_interruptible_sync_poll(sk->sk_sleep, POLLIN);
+}
+
+static void mp_sock_write_space(struct sock *sk)
+{
+ if (sk_has_sleeper(sk))
+ wake_up_interruptible_sync_poll(sk->sk_sleep, POLLOUT);
+}
+
+static long mp_chr_ioctl(struct file *file, unsigned int cmd,
+ unsigned long arg)
+{
+ struct mp_file *mfile = file->private_data;
+ struct mp_struct *mp;
+ struct net_device *dev;
+ void __user* argp = (void __user *)arg;
+ struct ifreq ifr;
+ struct sock *sk;
+ int ret;
+
+ ret = -EINVAL;
+
+ switch (cmd) {
+ case MPASSTHRU_BINDDEV:
+ ret = -EFAULT;
+ if (copy_from_user(&ifr, argp, sizeof ifr))
+ break;
+
+ ifr.ifr_name[IFNAMSIZ-1] = '\0';
+
+ ret = -EBUSY;
+
+ if (ifr.ifr_flags & IFF_MPASSTHRU_EXCL)
+ break;
+
+ ret = -ENODEV;
+ dev = dev_get_by_name(mfile->net, ifr.ifr_name);
+ if (!dev)
+ break;
+
+ mutex_lock(&mp_mutex);
+
+ ret = -EBUSY;
+ mp = mfile->mp;
+ if (mp)
+ goto err_dev_put;
+
+ mp = kzalloc(sizeof(*mp), GFP_KERNEL);
+ if (!mp) {
+ ret = -ENOMEM;
+ goto err_dev_put;
+ }
+ mp->dev = dev;
+ ret = -ENOMEM;
+
+ sk = sk_alloc(mfile->net, AF_UNSPEC, GFP_KERNEL, &mp_proto);
+ if (!sk)
+ goto err_free_mp;
+
+ init_waitqueue_head(&mp->socket.wait);
+ mp->socket.ops = &mp_socket_ops;
+ sock_init_data(&mp->socket, sk);
+ sk->sk_sndbuf = INT_MAX;
+ container_of(sk, struct mp_sock, sk)->mp = mp;
+
+ sk->sk_destruct = mp_sock_destruct;
+ sk->sk_data_ready = mp_sock_data_ready;
+ sk->sk_write_space = mp_sock_write_space;
+
+ ret = mp_attach(mp, file);
+ if (ret < 0)
+ goto err_free_sk;
+
+ ret = page_ctor_attach(mp);
+ if (ret < 0)
+ goto err_free_sk;
+
+ ifr.ifr_flags |= IFF_MPASSTHRU_EXCL;
+ mp_dev_change_flags(mp->dev, mp->dev->flags | IFF_UP);
+out:
+ mutex_unlock(&mp_mutex);
+ break;
+err_free_sk:
+ sk_free(sk);
+err_free_mp:
+ kfree(mp);
+err_dev_put:
+ dev_put(dev);
+ goto out;
+
+ case MPASSTHRU_UNBINDDEV:
+ ret = do_unbind(mfile);
+ break;
+
+ default:
+ break;
+ }
+ return ret;
+}
+
+static unsigned int mp_chr_poll(struct file *file, poll_table * wait)
+{
+ struct mp_file *mfile = file->private_data;
+ struct mp_struct *mp = mp_get(mfile);
+ struct sock *sk;
+ unsigned int mask = 0;
+
+ if (!mp)
+ return POLLERR;
+
+ sk = mp->socket.sk;
+
+ poll_wait(file, &mp->socket.wait, wait);
+
+ if (!skb_queue_empty(&sk->sk_receive_queue))
+ mask |= POLLIN | POLLRDNORM;
+
+ if (sock_writeable(sk) ||
+ (!test_and_set_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags) &&
+ sock_writeable(sk)))
+ mask |= POLLOUT | POLLWRNORM;
+
+ if (mp->dev->reg_state != NETREG_REGISTERED)
+ mask = POLLERR;
+
+ mp_put(mfile);
+ return mask;
+}
+
+static int mp_chr_close(struct inode *inode, struct file *file)
+{
+ struct mp_file *mfile = file->private_data;
+
+ /*
+ * Ignore return value since an error only means there was nothing to
+ * do
+ */
+ do_unbind(mfile);
+
+ put_net(mfile->net);
+ kfree(mfile);
+
+ return 0;
+}
+
+static const struct file_operations mp_fops = {
+ .owner = THIS_MODULE,
+ .llseek = no_llseek,
+ .poll = mp_chr_poll,
+ .unlocked_ioctl = mp_chr_ioctl,
+ .open = mp_chr_open,
+ .release = mp_chr_close,
+};
+
+static struct miscdevice mp_miscdev = {
+ .minor = MISC_DYNAMIC_MINOR,
+ .name = "mp",
+ .nodename = "net/mp",
+ .fops = &mp_fops,
+};
+
+static int mp_device_event(struct notifier_block *unused,
+ unsigned long event, void *ptr)
+{
+ struct net_device *dev = ptr;
+ struct mpassthru_port *port;
+ struct mp_struct *mp = NULL;
+ struct socket *sock = NULL;
+
+ port = dev->mp_port;
+ if (port == NULL)
+ return NOTIFY_DONE;
+
+ switch (event) {
+ case NETDEV_UNREGISTER:
+ sock = dev->mp_port->sock;
+ mp = container_of(sock->sk, struct mp_sock, sk)->mp;
+ do_unbind(mp->mfile);
+ break;
+ }
+ return NOTIFY_DONE;
+}
+
+static struct notifier_block mp_notifier_block __read_mostly = {
+ .notifier_call = mp_device_event,
+};
+
+static int mp_init(void)
+{
+ int ret = 0;
+
+ ret = misc_register(&mp_miscdev);
+ if (ret)
+ printk(KERN_ERR "mp: Can't register misc device\n");
+ else {
+ printk(KERN_INFO "Registering mp misc device - minor = %d\n",
+ mp_miscdev.minor);
+ register_netdevice_notifier(&mp_notifier_block);
+ }
+ return ret;
+}
+
+void mp_cleanup(void)
+{
+ unregister_netdevice_notifier(&mp_notifier_block);
+ misc_deregister(&mp_miscdev);
+}
+
+/* Get an underlying socket object from mp file. Returns error unless file is
+ * attached to a device. The returned object works like a packet socket, it
+ * can be used for sock_sendmsg/sock_recvmsg. The caller is responsible for
+ * holding a reference to the file for as long as the socket is in use. */
+struct socket *mp_get_socket(struct file *file)
+{
+ struct mp_file *mfile = file->private_data;
+ struct mp_struct *mp;
+
+ if (file->f_op != &mp_fops)
+ return ERR_PTR(-EINVAL);
+ mp = mp_get(mfile);
+ if (!mp)
+ return ERR_PTR(-EBADFD);
+ mp_put(mfile);
+ return &mp->socket;
+}
+EXPORT_SYMBOL_GPL(mp_get_socket);
+
+module_init(mp_init);
+module_exit(mp_cleanup);
+MODULE_AUTHOR(DRV_COPYRIGHT);
+MODULE_DESCRIPTION(DRV_DESCRIPTION);
+MODULE_LICENSE("GPL v2");
diff --git a/include/linux/mpassthru.h b/include/linux/mpassthru.h
new file mode 100644
index 0000000..2be21c5
--- /dev/null
+++ b/include/linux/mpassthru.h
@@ -0,0 +1,29 @@
+#ifndef __MPASSTHRU_H
+#define __MPASSTHRU_H
+
+#include <linux/types.h>
+#include <linux/if_ether.h>
+
+/* ioctl defines */
+#define MPASSTHRU_BINDDEV _IOW('M', 213, int)
+#define MPASSTHRU_UNBINDDEV _IOW('M', 214, int)
+
+/* MPASSTHRU ifc flags */
+#define IFF_MPASSTHRU 0x0001
+#define IFF_MPASSTHRU_EXCL 0x0002
+
+#ifdef __KERNEL__
+#if defined(CONFIG_VHOST_PASSTHRU) || defined(CONFIG_VHOST_PASSTHRU_MODULE)
+struct socket *mp_get_socket(struct file *);
+#else
+#include <linux/err.h>
+#include <linux/errno.h>
+struct file;
+struct socket;
+static inline struct socket *mp_get_socket(struct file *f)
+{
+ return ERR_PTR(-EINVAL);
+}
+#endif /* CONFIG_VHOST_PASSTHRU */
+#endif /* __KERNEL__ */
+#endif /* __MPASSTHRU_H */
--
1.5.4.4


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