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