1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * VFIO-KVM bridge pseudo device 4 * 5 * Copyright (C) 2013 Red Hat, Inc. All rights reserved. 6 * Author: Alex Williamson <alex.williamson@redhat.com> 7 */ 8 9 #include <linux/errno.h> 10 #include <linux/file.h> 11 #include <linux/kvm_host.h> 12 #include <linux/list.h> 13 #include <linux/module.h> 14 #include <linux/mutex.h> 15 #include <linux/slab.h> 16 #include <linux/uaccess.h> 17 #include <linux/vfio.h> 18 #include "vfio.h" 19 20 #ifdef CONFIG_SPAPR_TCE_IOMMU 21 #include <asm/kvm_ppc.h> 22 #endif 23 24 struct kvm_vfio_file { 25 struct list_head node; 26 struct file *file; 27 #ifdef CONFIG_SPAPR_TCE_IOMMU 28 struct iommu_group *iommu_group; 29 #endif 30 }; 31 32 struct kvm_vfio { 33 struct list_head file_list; 34 struct mutex lock; 35 bool noncoherent; 36 }; 37 38 static void kvm_vfio_file_set_kvm(struct file *file, struct kvm *kvm) 39 { 40 void (*fn)(struct file *file, struct kvm *kvm); 41 42 fn = symbol_get(vfio_file_set_kvm); 43 if (!fn) 44 return; 45 46 fn(file, kvm); 47 48 symbol_put(vfio_file_set_kvm); 49 } 50 51 static bool kvm_vfio_file_enforced_coherent(struct file *file) 52 { 53 bool (*fn)(struct file *file); 54 bool ret; 55 56 fn = symbol_get(vfio_file_enforced_coherent); 57 if (!fn) 58 return false; 59 60 ret = fn(file); 61 62 symbol_put(vfio_file_enforced_coherent); 63 64 return ret; 65 } 66 67 static bool kvm_vfio_file_is_valid(struct file *file) 68 { 69 bool (*fn)(struct file *file); 70 bool ret; 71 72 fn = symbol_get(vfio_file_is_valid); 73 if (!fn) 74 return false; 75 76 ret = fn(file); 77 78 symbol_put(vfio_file_is_valid); 79 80 return ret; 81 } 82 83 #ifdef CONFIG_SPAPR_TCE_IOMMU 84 static struct iommu_group *kvm_vfio_file_iommu_group(struct file *file) 85 { 86 struct iommu_group *(*fn)(struct file *file); 87 struct iommu_group *ret; 88 89 fn = symbol_get(vfio_file_iommu_group); 90 if (!fn) 91 return NULL; 92 93 ret = fn(file); 94 95 symbol_put(vfio_file_iommu_group); 96 97 return ret; 98 } 99 100 static void kvm_spapr_tce_release_vfio_group(struct kvm *kvm, 101 struct kvm_vfio_file *kvf) 102 { 103 if (WARN_ON_ONCE(!kvf->iommu_group)) 104 return; 105 106 kvm_spapr_tce_release_iommu_group(kvm, kvf->iommu_group); 107 iommu_group_put(kvf->iommu_group); 108 kvf->iommu_group = NULL; 109 } 110 #endif 111 112 /* 113 * Groups/devices can use the same or different IOMMU domains. If the same 114 * then adding a new group/device may change the coherency of groups/devices 115 * we've previously been told about. We don't want to care about any of 116 * that so we retest each group/device and bail as soon as we find one that's 117 * noncoherent. This means we only ever [un]register_noncoherent_dma once 118 * for the whole device. 119 */ 120 static void kvm_vfio_update_coherency(struct kvm_device *dev) 121 { 122 struct kvm_vfio *kv = dev->private; 123 bool noncoherent = false; 124 struct kvm_vfio_file *kvf; 125 126 list_for_each_entry(kvf, &kv->file_list, node) { 127 if (!kvm_vfio_file_enforced_coherent(kvf->file)) { 128 noncoherent = true; 129 break; 130 } 131 } 132 133 if (noncoherent != kv->noncoherent) { 134 kv->noncoherent = noncoherent; 135 136 if (kv->noncoherent) 137 kvm_arch_register_noncoherent_dma(dev->kvm); 138 else 139 kvm_arch_unregister_noncoherent_dma(dev->kvm); 140 } 141 } 142 143 static int kvm_vfio_file_add(struct kvm_device *dev, unsigned int fd) 144 { 145 struct kvm_vfio *kv = dev->private; 146 struct kvm_vfio_file *kvf; 147 struct file *filp; 148 int ret = 0; 149 150 filp = fget(fd); 151 if (!filp) 152 return -EBADF; 153 154 /* Ensure the FD is a vfio FD. */ 155 if (!kvm_vfio_file_is_valid(filp)) { 156 ret = -EINVAL; 157 goto out_fput; 158 } 159 160 mutex_lock(&kv->lock); 161 162 list_for_each_entry(kvf, &kv->file_list, node) { 163 if (kvf->file == filp) { 164 ret = -EEXIST; 165 goto out_unlock; 166 } 167 } 168 169 kvf = kzalloc(sizeof(*kvf), GFP_KERNEL_ACCOUNT); 170 if (!kvf) { 171 ret = -ENOMEM; 172 goto out_unlock; 173 } 174 175 kvf->file = get_file(filp); 176 list_add_tail(&kvf->node, &kv->file_list); 177 178 kvm_arch_start_assignment(dev->kvm); 179 kvm_vfio_file_set_kvm(kvf->file, dev->kvm); 180 kvm_vfio_update_coherency(dev); 181 182 out_unlock: 183 mutex_unlock(&kv->lock); 184 out_fput: 185 fput(filp); 186 return ret; 187 } 188 189 static int kvm_vfio_file_del(struct kvm_device *dev, unsigned int fd) 190 { 191 struct kvm_vfio *kv = dev->private; 192 struct kvm_vfio_file *kvf; 193 struct fd f; 194 int ret; 195 196 f = fdget(fd); 197 if (!f.file) 198 return -EBADF; 199 200 ret = -ENOENT; 201 202 mutex_lock(&kv->lock); 203 204 list_for_each_entry(kvf, &kv->file_list, node) { 205 if (kvf->file != f.file) 206 continue; 207 208 list_del(&kvf->node); 209 kvm_arch_end_assignment(dev->kvm); 210 #ifdef CONFIG_SPAPR_TCE_IOMMU 211 kvm_spapr_tce_release_vfio_group(dev->kvm, kvf); 212 #endif 213 kvm_vfio_file_set_kvm(kvf->file, NULL); 214 fput(kvf->file); 215 kfree(kvf); 216 ret = 0; 217 break; 218 } 219 220 kvm_vfio_update_coherency(dev); 221 222 mutex_unlock(&kv->lock); 223 224 fdput(f); 225 226 return ret; 227 } 228 229 #ifdef CONFIG_SPAPR_TCE_IOMMU 230 static int kvm_vfio_file_set_spapr_tce(struct kvm_device *dev, 231 void __user *arg) 232 { 233 struct kvm_vfio_spapr_tce param; 234 struct kvm_vfio *kv = dev->private; 235 struct kvm_vfio_file *kvf; 236 struct fd f; 237 int ret; 238 239 if (copy_from_user(¶m, arg, sizeof(struct kvm_vfio_spapr_tce))) 240 return -EFAULT; 241 242 f = fdget(param.groupfd); 243 if (!f.file) 244 return -EBADF; 245 246 ret = -ENOENT; 247 248 mutex_lock(&kv->lock); 249 250 list_for_each_entry(kvf, &kv->file_list, node) { 251 if (kvf->file != f.file) 252 continue; 253 254 if (!kvf->iommu_group) { 255 kvf->iommu_group = kvm_vfio_file_iommu_group(kvf->file); 256 if (WARN_ON_ONCE(!kvf->iommu_group)) { 257 ret = -EIO; 258 goto err_fdput; 259 } 260 } 261 262 ret = kvm_spapr_tce_attach_iommu_group(dev->kvm, param.tablefd, 263 kvf->iommu_group); 264 break; 265 } 266 267 err_fdput: 268 mutex_unlock(&kv->lock); 269 fdput(f); 270 return ret; 271 } 272 #endif 273 274 static int kvm_vfio_set_file(struct kvm_device *dev, long attr, 275 void __user *arg) 276 { 277 int32_t __user *argp = arg; 278 int32_t fd; 279 280 switch (attr) { 281 case KVM_DEV_VFIO_FILE_ADD: 282 if (get_user(fd, argp)) 283 return -EFAULT; 284 return kvm_vfio_file_add(dev, fd); 285 286 case KVM_DEV_VFIO_FILE_DEL: 287 if (get_user(fd, argp)) 288 return -EFAULT; 289 return kvm_vfio_file_del(dev, fd); 290 291 #ifdef CONFIG_SPAPR_TCE_IOMMU 292 case KVM_DEV_VFIO_GROUP_SET_SPAPR_TCE: 293 return kvm_vfio_file_set_spapr_tce(dev, arg); 294 #endif 295 } 296 297 return -ENXIO; 298 } 299 300 static int kvm_vfio_set_attr(struct kvm_device *dev, 301 struct kvm_device_attr *attr) 302 { 303 switch (attr->group) { 304 case KVM_DEV_VFIO_FILE: 305 return kvm_vfio_set_file(dev, attr->attr, 306 u64_to_user_ptr(attr->addr)); 307 } 308 309 return -ENXIO; 310 } 311 312 static int kvm_vfio_has_attr(struct kvm_device *dev, 313 struct kvm_device_attr *attr) 314 { 315 switch (attr->group) { 316 case KVM_DEV_VFIO_FILE: 317 switch (attr->attr) { 318 case KVM_DEV_VFIO_FILE_ADD: 319 case KVM_DEV_VFIO_FILE_DEL: 320 #ifdef CONFIG_SPAPR_TCE_IOMMU 321 case KVM_DEV_VFIO_GROUP_SET_SPAPR_TCE: 322 #endif 323 return 0; 324 } 325 326 break; 327 } 328 329 return -ENXIO; 330 } 331 332 static void kvm_vfio_release(struct kvm_device *dev) 333 { 334 struct kvm_vfio *kv = dev->private; 335 struct kvm_vfio_file *kvf, *tmp; 336 337 list_for_each_entry_safe(kvf, tmp, &kv->file_list, node) { 338 #ifdef CONFIG_SPAPR_TCE_IOMMU 339 kvm_spapr_tce_release_vfio_group(dev->kvm, kvf); 340 #endif 341 kvm_vfio_file_set_kvm(kvf->file, NULL); 342 fput(kvf->file); 343 list_del(&kvf->node); 344 kfree(kvf); 345 kvm_arch_end_assignment(dev->kvm); 346 } 347 348 kvm_vfio_update_coherency(dev); 349 350 kfree(kv); 351 kfree(dev); /* alloc by kvm_ioctl_create_device, free by .release */ 352 } 353 354 static int kvm_vfio_create(struct kvm_device *dev, u32 type); 355 356 static struct kvm_device_ops kvm_vfio_ops = { 357 .name = "kvm-vfio", 358 .create = kvm_vfio_create, 359 .release = kvm_vfio_release, 360 .set_attr = kvm_vfio_set_attr, 361 .has_attr = kvm_vfio_has_attr, 362 }; 363 364 static int kvm_vfio_create(struct kvm_device *dev, u32 type) 365 { 366 struct kvm_device *tmp; 367 struct kvm_vfio *kv; 368 369 /* Only one VFIO "device" per VM */ 370 list_for_each_entry(tmp, &dev->kvm->devices, vm_node) 371 if (tmp->ops == &kvm_vfio_ops) 372 return -EBUSY; 373 374 kv = kzalloc(sizeof(*kv), GFP_KERNEL_ACCOUNT); 375 if (!kv) 376 return -ENOMEM; 377 378 INIT_LIST_HEAD(&kv->file_list); 379 mutex_init(&kv->lock); 380 381 dev->private = kv; 382 383 return 0; 384 } 385 386 int kvm_vfio_ops_init(void) 387 { 388 return kvm_register_device_ops(&kvm_vfio_ops, KVM_DEV_TYPE_VFIO); 389 } 390 391 void kvm_vfio_ops_exit(void) 392 { 393 kvm_unregister_device_ops(KVM_DEV_TYPE_VFIO); 394 } 395