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 CLASS(fd, f)(fd); 194 int ret; 195 196 if (fd_empty(f)) 197 return -EBADF; 198 199 ret = -ENOENT; 200 201 mutex_lock(&kv->lock); 202 203 list_for_each_entry(kvf, &kv->file_list, node) { 204 if (kvf->file != fd_file(f)) 205 continue; 206 207 list_del(&kvf->node); 208 kvm_arch_end_assignment(dev->kvm); 209 #ifdef CONFIG_SPAPR_TCE_IOMMU 210 kvm_spapr_tce_release_vfio_group(dev->kvm, kvf); 211 #endif 212 kvm_vfio_file_set_kvm(kvf->file, NULL); 213 fput(kvf->file); 214 kfree(kvf); 215 ret = 0; 216 break; 217 } 218 219 kvm_vfio_update_coherency(dev); 220 221 mutex_unlock(&kv->lock); 222 return ret; 223 } 224 225 #ifdef CONFIG_SPAPR_TCE_IOMMU 226 static int kvm_vfio_file_set_spapr_tce(struct kvm_device *dev, 227 void __user *arg) 228 { 229 struct kvm_vfio_spapr_tce param; 230 struct kvm_vfio *kv = dev->private; 231 struct kvm_vfio_file *kvf; 232 int ret; 233 234 if (copy_from_user(¶m, arg, sizeof(struct kvm_vfio_spapr_tce))) 235 return -EFAULT; 236 237 CLASS(fd, f)(param.groupfd); 238 if (fd_empty(f)) 239 return -EBADF; 240 241 ret = -ENOENT; 242 243 mutex_lock(&kv->lock); 244 245 list_for_each_entry(kvf, &kv->file_list, node) { 246 if (kvf->file != fd_file(f)) 247 continue; 248 249 if (!kvf->iommu_group) { 250 kvf->iommu_group = kvm_vfio_file_iommu_group(kvf->file); 251 if (WARN_ON_ONCE(!kvf->iommu_group)) { 252 ret = -EIO; 253 goto err_fdput; 254 } 255 } 256 257 ret = kvm_spapr_tce_attach_iommu_group(dev->kvm, param.tablefd, 258 kvf->iommu_group); 259 break; 260 } 261 262 err_fdput: 263 mutex_unlock(&kv->lock); 264 return ret; 265 } 266 #endif 267 268 static int kvm_vfio_set_file(struct kvm_device *dev, long attr, 269 void __user *arg) 270 { 271 int32_t __user *argp = arg; 272 int32_t fd; 273 274 switch (attr) { 275 case KVM_DEV_VFIO_FILE_ADD: 276 if (get_user(fd, argp)) 277 return -EFAULT; 278 return kvm_vfio_file_add(dev, fd); 279 280 case KVM_DEV_VFIO_FILE_DEL: 281 if (get_user(fd, argp)) 282 return -EFAULT; 283 return kvm_vfio_file_del(dev, fd); 284 285 #ifdef CONFIG_SPAPR_TCE_IOMMU 286 case KVM_DEV_VFIO_GROUP_SET_SPAPR_TCE: 287 return kvm_vfio_file_set_spapr_tce(dev, arg); 288 #endif 289 } 290 291 return -ENXIO; 292 } 293 294 static int kvm_vfio_set_attr(struct kvm_device *dev, 295 struct kvm_device_attr *attr) 296 { 297 switch (attr->group) { 298 case KVM_DEV_VFIO_FILE: 299 return kvm_vfio_set_file(dev, attr->attr, 300 u64_to_user_ptr(attr->addr)); 301 } 302 303 return -ENXIO; 304 } 305 306 static int kvm_vfio_has_attr(struct kvm_device *dev, 307 struct kvm_device_attr *attr) 308 { 309 switch (attr->group) { 310 case KVM_DEV_VFIO_FILE: 311 switch (attr->attr) { 312 case KVM_DEV_VFIO_FILE_ADD: 313 case KVM_DEV_VFIO_FILE_DEL: 314 #ifdef CONFIG_SPAPR_TCE_IOMMU 315 case KVM_DEV_VFIO_GROUP_SET_SPAPR_TCE: 316 #endif 317 return 0; 318 } 319 320 break; 321 } 322 323 return -ENXIO; 324 } 325 326 static void kvm_vfio_release(struct kvm_device *dev) 327 { 328 struct kvm_vfio *kv = dev->private; 329 struct kvm_vfio_file *kvf, *tmp; 330 331 list_for_each_entry_safe(kvf, tmp, &kv->file_list, node) { 332 #ifdef CONFIG_SPAPR_TCE_IOMMU 333 kvm_spapr_tce_release_vfio_group(dev->kvm, kvf); 334 #endif 335 kvm_vfio_file_set_kvm(kvf->file, NULL); 336 fput(kvf->file); 337 list_del(&kvf->node); 338 kfree(kvf); 339 kvm_arch_end_assignment(dev->kvm); 340 } 341 342 kvm_vfio_update_coherency(dev); 343 344 kfree(kv); 345 kfree(dev); /* alloc by kvm_ioctl_create_device, free by .release */ 346 } 347 348 static int kvm_vfio_create(struct kvm_device *dev, u32 type); 349 350 static const struct kvm_device_ops kvm_vfio_ops = { 351 .name = "kvm-vfio", 352 .create = kvm_vfio_create, 353 .release = kvm_vfio_release, 354 .set_attr = kvm_vfio_set_attr, 355 .has_attr = kvm_vfio_has_attr, 356 }; 357 358 static int kvm_vfio_create(struct kvm_device *dev, u32 type) 359 { 360 struct kvm_device *tmp; 361 struct kvm_vfio *kv; 362 363 lockdep_assert_held(&dev->kvm->lock); 364 365 /* Only one VFIO "device" per VM */ 366 list_for_each_entry(tmp, &dev->kvm->devices, vm_node) 367 if (tmp->ops == &kvm_vfio_ops) 368 return -EBUSY; 369 370 kv = kzalloc(sizeof(*kv), GFP_KERNEL_ACCOUNT); 371 if (!kv) 372 return -ENOMEM; 373 374 INIT_LIST_HEAD(&kv->file_list); 375 mutex_init(&kv->lock); 376 377 dev->private = kv; 378 379 return 0; 380 } 381 382 int kvm_vfio_ops_init(void) 383 { 384 return kvm_register_device_ops(&kvm_vfio_ops, KVM_DEV_TYPE_VFIO); 385 } 386 387 void kvm_vfio_ops_exit(void) 388 { 389 kvm_unregister_device_ops(KVM_DEV_TYPE_VFIO); 390 } 391