hw/virtio/vhost-backend.c

   1 /*
   2  * vhost-backend
   3  *
   4  * Copyright (c) 2013 Virtual Open Systems Sarl.
   5  *
   6  * This work is licensed under the terms of the GNU GPL, version 2 or later.
   7  * See the COPYING file in the top-level directory.
   8  *
   9  */
  10
  11 #include "hw/virtio/vhost.h"
  12 #include "hw/virtio/vhost-backend.h"
  13 #include "qemu/error-report.h"
  14
  15 #include <sys/ioctl.h>
  16
  17 static int vhost_kernel_call(struct vhost_dev *dev, unsigned long int request,
  18                              void *arg)
  19 {
  20     int fd = (uintptr_t) dev->opaque;
  21
  22     assert(dev->vhost_ops->backend_type == VHOST_BACKEND_TYPE_KERNEL);
  23
  24     return ioctl(fd, request, arg);
  25 }
  26
  27 static int vhost_kernel_init(struct vhost_dev *dev, void *opaque)
  28 {
  29     assert(dev->vhost_ops->backend_type == VHOST_BACKEND_TYPE_KERNEL);
  30
  31     dev->opaque = opaque;
  32
  33     return 0;
  34 }
  35
  36 static int vhost_kernel_cleanup(struct vhost_dev *dev)
  37 {
  38     int fd = (uintptr_t) dev->opaque;
  39
  40     assert(dev->vhost_ops->backend_type == VHOST_BACKEND_TYPE_KERNEL);
  41
  42     return close(fd);
  43 }
  44
  45 static int vhost_kernel_get_vq_index(struct vhost_dev *dev, int idx)
  46 {
  47     assert(idx >= dev->vq_index && idx < dev->vq_index + dev->nvqs);
  48
  49     return idx - dev->vq_index;
  50 }
  51
  52 static const VhostOps kernel_ops = {
  53         .backend_type = VHOST_BACKEND_TYPE_KERNEL,
  54         .vhost_call = vhost_kernel_call,
  55         .vhost_backend_init = vhost_kernel_init,
  56         .vhost_backend_cleanup = vhost_kernel_cleanup,
  57         .vhost_backend_get_vq_index = vhost_kernel_get_vq_index,
  58 };
  59
  60 int vhost_set_backend_type(struct vhost_dev *dev, VhostBackendType backend_type)
  61 {
  62     int r = 0;
  63
  64     switch (backend_type) {
  65     case VHOST_BACKEND_TYPE_KERNEL:
  66         dev->vhost_ops = &kernel_ops;
  67         break;
  68     case VHOST_BACKEND_TYPE_USER:
  69         dev->vhost_ops = &user_ops;
  70         break;
  71     default:
  72         error_report("Unknown vhost backend type");
  73         r = -1;
  74     }
  75
  76     return r;
  77 }