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(&n->dev, 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        int r;
 108
 109        if (!n)
 110                return -ENOMEM;
 111        vqs = kmalloc(VHOST_TEST_VQ_MAX * sizeof(*vqs), GFP_KERNEL);
 112        if (!vqs) {
 113                kfree(n);
 114                return -ENOMEM;
 115        }
 116
 117        dev = &n->dev;
 118        vqs[VHOST_TEST_VQ] = &n->vqs[VHOST_TEST_VQ];
 119        n->vqs[VHOST_TEST_VQ].handle_kick = handle_vq_kick;
 120        r = vhost_dev_init(dev, vqs, VHOST_TEST_VQ_MAX);
 121        if (r < 0) {
 122                kfree(vqs);
 123                kfree(n);
 124                return r;
 125        }
 126
 127        f->private_data = n;
 128
 129        return 0;
 130}
 131
 132static void *vhost_test_stop_vq(struct vhost_test *n,
 133                                struct vhost_virtqueue *vq)
 134{
 135        void *private;
 136
 137        mutex_lock(&vq->mutex);
 138        private = vq->private_data;
 139        vq->private_data = NULL;
 140        mutex_unlock(&vq->mutex);
 141        return private;
 142}
 143
 144static void vhost_test_stop(struct vhost_test *n, void **privatep)
 145{
 146        *privatep = vhost_test_stop_vq(n, n->vqs + VHOST_TEST_VQ);
 147}
 148
 149static void vhost_test_flush_vq(struct vhost_test *n, int index)
 150{
 151        vhost_poll_flush(&n->vqs[index].poll);
 152}
 153
 154static void vhost_test_flush(struct vhost_test *n)
 155{
 156        vhost_test_flush_vq(n, VHOST_TEST_VQ);
 157}
 158
 159static int vhost_test_release(struct inode *inode, struct file *f)
 160{
 161        struct vhost_test *n = f->private_data;
 162        void  *private;
 163
 164        vhost_test_stop(n, &private);
 165        vhost_test_flush(n);
 166        vhost_dev_cleanup(&n->dev, false);
 167        /* We do an extra flush before freeing memory,
 168         * since jobs can re-queue themselves. */
 169        vhost_test_flush(n);
 170        kfree(n);
 171        return 0;
 172}
 173
 174static long vhost_test_run(struct vhost_test *n, int test)
 175{
 176        void *priv, *oldpriv;
 177        struct vhost_virtqueue *vq;
 178        int r, index;
 179
 180        if (test < 0 || test > 1)
 181                return -EINVAL;
 182
 183        mutex_lock(&n->dev.mutex);
 184        r = vhost_dev_check_owner(&n->dev);
 185        if (r)
 186                goto err;
 187
 188        for (index = 0; index < n->dev.nvqs; ++index) {
 189                /* Verify that ring has been setup correctly. */
 190                if (!vhost_vq_access_ok(&n->vqs[index])) {
 191                        r = -EFAULT;
 192                        goto err;
 193                }
 194        }
 195
 196        for (index = 0; index < n->dev.nvqs; ++index) {
 197                vq = n->vqs + index;
 198                mutex_lock(&vq->mutex);
 199                priv = test ? n : NULL;
 200
 201                /* start polling new socket */
 202                oldpriv = vq->private_data;
 203                vq->private_data = priv;
 204
 205                r = vhost_init_used(&n->vqs[index]);
 206
 207                mutex_unlock(&vq->mutex);
 208
 209                if (r)
 210                        goto err;
 211
 212                if (oldpriv) {
 213                        vhost_test_flush_vq(n, index);
 214                }
 215        }
 216
 217        mutex_unlock(&n->dev.mutex);
 218        return 0;
 219
 220err:
 221        mutex_unlock(&n->dev.mutex);
 222        return r;
 223}
 224
 225static long vhost_test_reset_owner(struct vhost_test *n)
 226{
 227        void *priv = NULL;
 228        long err;
 229        struct vhost_memory *memory;
 230
 231        mutex_lock(&n->dev.mutex);
 232        err = vhost_dev_check_owner(&n->dev);
 233        if (err)
 234                goto done;
 235        memory = vhost_dev_reset_owner_prepare();
 236        if (!memory) {
 237                err = -ENOMEM;
 238                goto done;
 239        }
 240        vhost_test_stop(n, &priv);
 241        vhost_test_flush(n);
 242        vhost_dev_reset_owner(&n->dev, memory);
 243done:
 244        mutex_unlock(&n->dev.mutex);
 245        return err;
 246}
 247
 248static int vhost_test_set_features(struct vhost_test *n, u64 features)
 249{
 250        mutex_lock(&n->dev.mutex);
 251        if ((features & (1 << VHOST_F_LOG_ALL)) &&
 252            !vhost_log_access_ok(&n->dev)) {
 253                mutex_unlock(&n->dev.mutex);
 254                return -EFAULT;
 255        }
 256        n->dev.acked_features = features;
 257        smp_wmb();
 258        vhost_test_flush(n);
 259        mutex_unlock(&n->dev.mutex);
 260        return 0;
 261}
 262
 263static long vhost_test_ioctl(struct file *f, unsigned int ioctl,
 264                             unsigned long arg)
 265{
 266        struct vhost_test *n = f->private_data;
 267        void __user *argp = (void __user *)arg;
 268        u64 __user *featurep = argp;
 269        int test;
 270        u64 features;
 271        int r;
 272        switch (ioctl) {
 273        case VHOST_TEST_RUN:
 274                if (copy_from_user(&test, argp, sizeof test))
 275                        return -EFAULT;
 276                return vhost_test_run(n, test);
 277        case VHOST_GET_FEATURES:
 278                features = VHOST_FEATURES;
 279                if (copy_to_user(featurep, &features, sizeof features))
 280                        return -EFAULT;
 281                return 0;
 282        case VHOST_SET_FEATURES:
 283                if (copy_from_user(&features, featurep, sizeof features))
 284                        return -EFAULT;
 285                if (features & ~VHOST_FEATURES)
 286                        return -EOPNOTSUPP;
 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};
 325
 326static int vhost_test_init(void)
 327{
 328        return misc_register(&vhost_test_misc);
 329}
 330module_init(vhost_test_init);
 331
 332static void vhost_test_exit(void)
 333{
 334        misc_deregister(&vhost_test_misc);
 335}
 336module_exit(vhost_test_exit);
 337
 338MODULE_VERSION("0.0.1");
 339MODULE_LICENSE("GPL v2");
 340MODULE_AUTHOR("Michael S. Tsirkin");
 341MODULE_DESCRIPTION("Host kernel side for virtio simulator");
 342
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