xref: /qemu/hw/virtio/vhost-backend.c (revision 4f2d31fb) 
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 #include "linux/vhost.h"
15 
16 #include <sys/ioctl.h>
17 
18 static int vhost_kernel_call(struct vhost_dev *dev, unsigned long int request,
19                              void *arg)
20 {
21     int fd = (uintptr_t) dev->opaque;
22 
23     assert(dev->vhost_ops->backend_type == VHOST_BACKEND_TYPE_KERNEL);
24 
25     return ioctl(fd, request, arg);
26 }
27 
28 static int vhost_kernel_init(struct vhost_dev *dev, void *opaque)
29 {
30     assert(dev->vhost_ops->backend_type == VHOST_BACKEND_TYPE_KERNEL);
31 
32     dev->opaque = opaque;
33 
34     return 0;
35 }
36 
37 static int vhost_kernel_cleanup(struct vhost_dev *dev)
38 {
39     int fd = (uintptr_t) dev->opaque;
40 
41     assert(dev->vhost_ops->backend_type == VHOST_BACKEND_TYPE_KERNEL);
42 
43     return close(fd);
44 }
45 
46 static int vhost_kernel_memslots_limit(struct vhost_dev *dev)
47 {
48     int limit = 64;
49     char *s;
50 
51     if (g_file_get_contents("/sys/module/vhost/parameters/max_mem_regions",
52                             &s, NULL, NULL)) {
53         uint64_t val = g_ascii_strtoull(s, NULL, 10);
54         if (!((val == G_MAXUINT64 || !val) && errno)) {
55             return val;
56         }
57         error_report("ignoring invalid max_mem_regions value in vhost module:"
58                      " %s", s);
59     }
60     return limit;
61 }
62 
63 static int vhost_kernel_net_set_backend(struct vhost_dev *dev,
64                                         struct vhost_vring_file *file)
65 {
66     return vhost_kernel_call(dev, VHOST_NET_SET_BACKEND, file);
67 }
68 
69 static int vhost_kernel_scsi_set_endpoint(struct vhost_dev *dev,
70                                           struct vhost_scsi_target *target)
71 {
72     return vhost_kernel_call(dev, VHOST_SCSI_SET_ENDPOINT, target);
73 }
74 
75 static int vhost_kernel_scsi_clear_endpoint(struct vhost_dev *dev,
76                                             struct vhost_scsi_target *target)
77 {
78     return vhost_kernel_call(dev, VHOST_SCSI_CLEAR_ENDPOINT, target);
79 }
80 
81 static int vhost_kernel_scsi_get_abi_version(struct vhost_dev *dev, int *version)
82 {
83     return vhost_kernel_call(dev, VHOST_SCSI_GET_ABI_VERSION, version);
84 }
85 
86 static int vhost_kernel_set_log_base(struct vhost_dev *dev, uint64_t base,
87                                      struct vhost_log *log)
88 {
89     return vhost_kernel_call(dev, VHOST_SET_LOG_BASE, &base);
90 }
91 
92 static int vhost_kernel_set_mem_table(struct vhost_dev *dev,
93                                       struct vhost_memory *mem)
94 {
95     return vhost_kernel_call(dev, VHOST_SET_MEM_TABLE, mem);
96 }
97 
98 static int vhost_kernel_set_vring_addr(struct vhost_dev *dev,
99                                        struct vhost_vring_addr *addr)
100 {
101     return vhost_kernel_call(dev, VHOST_SET_VRING_ADDR, addr);
102 }
103 
104 static int vhost_kernel_set_vring_endian(struct vhost_dev *dev,
105                                          struct vhost_vring_state *ring)
106 {
107     return vhost_kernel_call(dev, VHOST_SET_VRING_ENDIAN, ring);
108 }
109 
110 static int vhost_kernel_set_vring_num(struct vhost_dev *dev,
111                                       struct vhost_vring_state *ring)
112 {
113     return vhost_kernel_call(dev, VHOST_SET_VRING_NUM, ring);
114 }
115 
116 static int vhost_kernel_set_vring_base(struct vhost_dev *dev,
117                                        struct vhost_vring_state *ring)
118 {
119     return vhost_kernel_call(dev, VHOST_SET_VRING_BASE, ring);
120 }
121 
122 static int vhost_kernel_get_vring_base(struct vhost_dev *dev,
123                                        struct vhost_vring_state *ring)
124 {
125     return vhost_kernel_call(dev, VHOST_GET_VRING_BASE, ring);
126 }
127 
128 static int vhost_kernel_set_vring_kick(struct vhost_dev *dev,
129                                        struct vhost_vring_file *file)
130 {
131     return vhost_kernel_call(dev, VHOST_SET_VRING_KICK, file);
132 }
133 
134 static int vhost_kernel_set_vring_call(struct vhost_dev *dev,
135                                        struct vhost_vring_file *file)
136 {
137     return vhost_kernel_call(dev, VHOST_SET_VRING_CALL, file);
138 }
139 
140 static int vhost_kernel_set_features(struct vhost_dev *dev,
141                                      uint64_t features)
142 {
143     return vhost_kernel_call(dev, VHOST_SET_FEATURES, &features);
144 }
145 
146 static int vhost_kernel_get_features(struct vhost_dev *dev,
147                                      uint64_t *features)
148 {
149     return vhost_kernel_call(dev, VHOST_GET_FEATURES, features);
150 }
151 
152 static int vhost_kernel_set_owner(struct vhost_dev *dev)
153 {
154     return vhost_kernel_call(dev, VHOST_SET_OWNER, NULL);
155 }
156 
157 static int vhost_kernel_reset_device(struct vhost_dev *dev)
158 {
159     return vhost_kernel_call(dev, VHOST_RESET_OWNER, NULL);
160 }
161 
162 static int vhost_kernel_get_vq_index(struct vhost_dev *dev, int idx)
163 {
164     assert(idx >= dev->vq_index && idx < dev->vq_index + dev->nvqs);
165 
166     return idx - dev->vq_index;
167 }
168 
169 static const VhostOps kernel_ops = {
170         .backend_type = VHOST_BACKEND_TYPE_KERNEL,
171         .vhost_backend_init = vhost_kernel_init,
172         .vhost_backend_cleanup = vhost_kernel_cleanup,
173         .vhost_backend_memslots_limit = vhost_kernel_memslots_limit,
174         .vhost_net_set_backend = vhost_kernel_net_set_backend,
175         .vhost_scsi_set_endpoint = vhost_kernel_scsi_set_endpoint,
176         .vhost_scsi_clear_endpoint = vhost_kernel_scsi_clear_endpoint,
177         .vhost_scsi_get_abi_version = vhost_kernel_scsi_get_abi_version,
178         .vhost_set_log_base = vhost_kernel_set_log_base,
179         .vhost_set_mem_table = vhost_kernel_set_mem_table,
180         .vhost_set_vring_addr = vhost_kernel_set_vring_addr,
181         .vhost_set_vring_endian = vhost_kernel_set_vring_endian,
182         .vhost_set_vring_num = vhost_kernel_set_vring_num,
183         .vhost_set_vring_base = vhost_kernel_set_vring_base,
184         .vhost_get_vring_base = vhost_kernel_get_vring_base,
185         .vhost_set_vring_kick = vhost_kernel_set_vring_kick,
186         .vhost_set_vring_call = vhost_kernel_set_vring_call,
187         .vhost_set_features = vhost_kernel_set_features,
188         .vhost_get_features = vhost_kernel_get_features,
189         .vhost_set_owner = vhost_kernel_set_owner,
190         .vhost_reset_device = vhost_kernel_reset_device,
191         .vhost_get_vq_index = vhost_kernel_get_vq_index,
192 };
193 
194 int vhost_set_backend_type(struct vhost_dev *dev, VhostBackendType backend_type)
195 {
196     int r = 0;
197 
198     switch (backend_type) {
199     case VHOST_BACKEND_TYPE_KERNEL:
200         dev->vhost_ops = &kernel_ops;
201         break;
202     case VHOST_BACKEND_TYPE_USER:
203         dev->vhost_ops = &user_ops;
204         break;
205     default:
206         error_report("Unknown vhost backend type");
207         r = -1;
208     }
209 
210     return r;
211 }
212