linux/drivers/vhost/test.c
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   1/* Copyright (C) 2009 Red Hat, Inc.
   2 * Author: Michael S. Tsirkin <mst@redhat.com>
   3 *
   4 * This work is licensed under the terms of the GNU GPL, version 2.
   5 *
   6 * test virtio server in host kernel.
   7 */
   8
   9#include <linux/compat.h>
  10#include <linux/eventfd.h>
  11#include <linux/vhost.h>
  12#include <linux/miscdevice.h>
  13#include <linux/module.h>
  14#include <linux/mutex.h>
  15#include <linux/workqueue.h>
  16#include <linux/file.h>
  17#include <linux/slab.h>
  18
  19#include "test.h"
  20#include "vhost.h"
  21
  22/* Max number of bytes transferred before requeueing the job.
  23 * Using this limit prevents one virtqueue from starving others. */
  24#define VHOST_TEST_WEIGHT 0x80000
  25
  26enum {
  27        VHOST_TEST_VQ = 0,
  28        VHOST_TEST_VQ_MAX = 1,
  29};
  30
  31struct vhost_test {
  32        struct vhost_dev dev;
  33        struct vhost_virtqueue vqs[VHOST_TEST_VQ_MAX];
  34};
  35
  36/* Expects to be always run from workqueue - which acts as
  37 * read-size critical section for our kind of RCU. */
  38static void handle_vq(struct vhost_test *n)
  39{
  40        struct vhost_virtqueue *vq = &n->vqs[VHOST_TEST_VQ];
  41        unsigned out, in;
  42        int head;
  43        size_t len, total_len = 0;
  44        void *private;
  45
  46        mutex_lock(&vq->mutex);
  47        private = vq->private_data;
  48        if (!private) {
  49                mutex_unlock(&vq->mutex);
  50                return;
  51        }
  52
  53        vhost_disable_notify(&n->dev, vq);
  54
  55        for (;;) {
  56                head = vhost_get_vq_desc(vq, vq->iov,
  57                                         ARRAY_SIZE(vq->iov),
  58                                         &out, &in,
  59                                         NULL, NULL);
  60                /* On error, stop handling until the next kick. */
  61                if (unlikely(head < 0))
  62                        break;
  63                /* Nothing new?  Wait for eventfd to tell us they refilled. */
  64                if (head == vq->num) {
  65                        if (unlikely(vhost_enable_notify(&n->dev, vq))) {
  66                                vhost_disable_notify(&n->dev, vq);
  67                                continue;
  68                        }
  69                        break;
  70                }
  71                if (in) {
  72                        vq_err(vq, "Unexpected descriptor format for TX: "
  73                               "out %d, int %d\n", out, in);
  74                        break;
  75                }
  76                len = iov_length(vq->iov, out);
  77                /* Sanity check */
  78                if (!len) {
  79                        vq_err(vq, "Unexpected 0 len for TX\n");
  80                        break;
  81                }
  82                vhost_add_used_and_signal(&n->dev, vq, head, 0);
  83                total_len += len;
  84                if (unlikely(total_len >= VHOST_TEST_WEIGHT)) {
  85                        vhost_poll_queue(&vq->poll);
  86                        break;
  87                }
  88        }
  89
  90        mutex_unlock(&vq->mutex);
  91}
  92
  93static void handle_vq_kick(struct vhost_work *work)
  94{
  95        struct vhost_virtqueue *vq = container_of(work, struct vhost_virtqueue,
  96                                                  poll.work);
  97        struct vhost_test *n = container_of(vq->dev, struct vhost_test, dev);
  98
  99        handle_vq(n);
 100}
 101
 102static int vhost_test_open(struct inode *inode, struct file *f)
 103{
 104        struct vhost_test *n = kmalloc(sizeof *n, GFP_KERNEL);
 105        struct vhost_dev *dev;
 106        struct vhost_virtqueue **vqs;
 107
 108        if (!n)
 109                return -ENOMEM;
 110        vqs = kmalloc_array(VHOST_TEST_VQ_MAX, sizeof(*vqs), GFP_KERNEL);
 111        if (!vqs) {
 112                kfree(n);
 113                return -ENOMEM;
 114        }
 115
 116        dev = &n->dev;
 117        vqs[VHOST_TEST_VQ] = &n->vqs[VHOST_TEST_VQ];
 118        n->vqs[VHOST_TEST_VQ].handle_kick = handle_vq_kick;
 119        vhost_dev_init(dev, vqs, VHOST_TEST_VQ_MAX);
 120
 121        f->private_data = n;
 122
 123        return 0;
 124}
 125
 126static void *vhost_test_stop_vq(struct vhost_test *n,
 127                                struct vhost_virtqueue *vq)
 128{
 129        void *private;
 130
 131        mutex_lock(&vq->mutex);
 132        private = vq->private_data;
 133        vq->private_data = NULL;
 134        mutex_unlock(&vq->mutex);
 135        return private;
 136}
 137
 138static void vhost_test_stop(struct vhost_test *n, void **privatep)
 139{
 140        *privatep = vhost_test_stop_vq(n, n->vqs + VHOST_TEST_VQ);
 141}
 142
 143static void vhost_test_flush_vq(struct vhost_test *n, int index)
 144{
 145        vhost_poll_flush(&n->vqs[index].poll);
 146}
 147
 148static void vhost_test_flush(struct vhost_test *n)
 149{
 150        vhost_test_flush_vq(n, VHOST_TEST_VQ);
 151}
 152
 153static int vhost_test_release(struct inode *inode, struct file *f)
 154{
 155        struct vhost_test *n = f->private_data;
 156        void  *private;
 157
 158        vhost_test_stop(n, &private);
 159        vhost_test_flush(n);
 160        vhost_dev_cleanup(&n->dev);
 161        /* We do an extra flush before freeing memory,
 162         * since jobs can re-queue themselves. */
 163        vhost_test_flush(n);
 164        kfree(n);
 165        return 0;
 166}
 167
 168static long vhost_test_run(struct vhost_test *n, int test)
 169{
 170        void *priv, *oldpriv;
 171        struct vhost_virtqueue *vq;
 172        int r, index;
 173
 174        if (test < 0 || test > 1)
 175                return -EINVAL;
 176
 177        mutex_lock(&n->dev.mutex);
 178        r = vhost_dev_check_owner(&n->dev);
 179        if (r)
 180                goto err;
 181
 182        for (index = 0; index < n->dev.nvqs; ++index) {
 183                /* Verify that ring has been setup correctly. */
 184                if (!vhost_vq_access_ok(&n->vqs[index])) {
 185                        r = -EFAULT;
 186                        goto err;
 187                }
 188        }
 189
 190        for (index = 0; index < n->dev.nvqs; ++index) {
 191                vq = n->vqs + index;
 192                mutex_lock(&vq->mutex);
 193                priv = test ? n : NULL;
 194
 195                /* start polling new socket */
 196                oldpriv = vq->private_data;
 197                vq->private_data = priv;
 198
 199                r = vhost_vq_init_access(&n->vqs[index]);
 200
 201                mutex_unlock(&vq->mutex);
 202
 203                if (r)
 204                        goto err;
 205
 206                if (oldpriv) {
 207                        vhost_test_flush_vq(n, index);
 208                }
 209        }
 210
 211        mutex_unlock(&n->dev.mutex);
 212        return 0;
 213
 214err:
 215        mutex_unlock(&n->dev.mutex);
 216        return r;
 217}
 218
 219static long vhost_test_reset_owner(struct vhost_test *n)
 220{
 221        void *priv = NULL;
 222        long err;
 223        struct vhost_umem *umem;
 224
 225        mutex_lock(&n->dev.mutex);
 226        err = vhost_dev_check_owner(&n->dev);
 227        if (err)
 228                goto done;
 229        umem = vhost_dev_reset_owner_prepare();
 230        if (!umem) {
 231                err = -ENOMEM;
 232                goto done;
 233        }
 234        vhost_test_stop(n, &priv);
 235        vhost_test_flush(n);
 236        vhost_dev_reset_owner(&n->dev, umem);
 237done:
 238        mutex_unlock(&n->dev.mutex);
 239        return err;
 240}
 241
 242static int vhost_test_set_features(struct vhost_test *n, u64 features)
 243{
 244        struct vhost_virtqueue *vq;
 245
 246        mutex_lock(&n->dev.mutex);
 247        if ((features & (1 << VHOST_F_LOG_ALL)) &&
 248            !vhost_log_access_ok(&n->dev)) {
 249                mutex_unlock(&n->dev.mutex);
 250                return -EFAULT;
 251        }
 252        vq = &n->vqs[VHOST_TEST_VQ];
 253        mutex_lock(&vq->mutex);
 254        vq->acked_features = features;
 255        mutex_unlock(&vq->mutex);
 256        mutex_unlock(&n->dev.mutex);
 257        return 0;
 258}
 259
 260static long vhost_test_ioctl(struct file *f, unsigned int ioctl,
 261                             unsigned long arg)
 262{
 263        struct vhost_test *n = f->private_data;
 264        void __user *argp = (void __user *)arg;
 265        u64 __user *featurep = argp;
 266        int test;
 267        u64 features;
 268        int r;
 269        switch (ioctl) {
 270        case VHOST_TEST_RUN:
 271                if (copy_from_user(&test, argp, sizeof test))
 272                        return -EFAULT;
 273                return vhost_test_run(n, test);
 274        case VHOST_GET_FEATURES:
 275                features = VHOST_FEATURES;
 276                if (copy_to_user(featurep, &features, sizeof features))
 277                        return -EFAULT;
 278                return 0;
 279        case VHOST_SET_FEATURES:
 280                printk(KERN_ERR "1\n");
 281                if (copy_from_user(&features, featurep, sizeof features))
 282                        return -EFAULT;
 283                printk(KERN_ERR "2\n");
 284                if (features & ~VHOST_FEATURES)
 285                        return -EOPNOTSUPP;
 286                printk(KERN_ERR "3\n");
 287                return vhost_test_set_features(n, features);
 288        case VHOST_RESET_OWNER:
 289                return vhost_test_reset_owner(n);
 290        default:
 291                mutex_lock(&n->dev.mutex);
 292                r = vhost_dev_ioctl(&n->dev, ioctl, argp);
 293                if (r == -ENOIOCTLCMD)
 294                        r = vhost_vring_ioctl(&n->dev, ioctl, argp);
 295                vhost_test_flush(n);
 296                mutex_unlock(&n->dev.mutex);
 297                return r;
 298        }
 299}
 300
 301#ifdef CONFIG_COMPAT
 302static long vhost_test_compat_ioctl(struct file *f, unsigned int ioctl,
 303                                   unsigned long arg)
 304{
 305        return vhost_test_ioctl(f, ioctl, (unsigned long)compat_ptr(arg));
 306}
 307#endif
 308
 309static const struct file_operations vhost_test_fops = {
 310        .owner          = THIS_MODULE,
 311        .release        = vhost_test_release,
 312        .unlocked_ioctl = vhost_test_ioctl,
 313#ifdef CONFIG_COMPAT
 314        .compat_ioctl   = vhost_test_compat_ioctl,
 315#endif
 316        .open           = vhost_test_open,
 317        .llseek         = noop_llseek,
 318};
 319
 320static struct miscdevice vhost_test_misc = {
 321        MISC_DYNAMIC_MINOR,
 322        "vhost-test",
 323        &vhost_test_fops,
 324};
 325module_misc_device(vhost_test_misc);
 326
 327MODULE_VERSION("0.0.1");
 328MODULE_LICENSE("GPL v2");
 329MODULE_AUTHOR("Michael S. Tsirkin");
 330MODULE_DESCRIPTION("Host kernel side for virtio simulator");
 331