xref: /openbmc/qemu/hw/virtio/vhost-backend.c (revision ddbb0d09)
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 const VhostOps kernel_ops = {
46         .backend_type = VHOST_BACKEND_TYPE_KERNEL,
47         .vhost_call = vhost_kernel_call,
48         .vhost_backend_init = vhost_kernel_init,
49         .vhost_backend_cleanup = vhost_kernel_cleanup
50 };
51 
52 int vhost_set_backend_type(struct vhost_dev *dev, VhostBackendType backend_type)
53 {
54     int r = 0;
55 
56     switch (backend_type) {
57     case VHOST_BACKEND_TYPE_KERNEL:
58         dev->vhost_ops = &kernel_ops;
59         break;
60     case VHOST_BACKEND_TYPE_USER:
61         dev->vhost_ops = &user_ops;
62         break;
63     default:
64         error_report("Unknown vhost backend type");
65         r = -1;
66     }
67 
68     return r;
69 }
70