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_vfio_file_set_kvm(kvf->file, dev->kvm); 179 kvm_vfio_update_coherency(dev); 180 181 out_unlock: 182 mutex_unlock(&kv->lock); 183 out_fput: 184 fput(filp); 185 return ret; 186 } 187 188 static int kvm_vfio_file_del(struct kvm_device *dev, unsigned int fd) 189 { 190 struct kvm_vfio *kv = dev->private; 191 struct kvm_vfio_file *kvf; 192 CLASS(fd, f)(fd); 193 int ret; 194 195 if (fd_empty(f)) 196 return -EBADF; 197 198 ret = -ENOENT; 199 200 mutex_lock(&kv->lock); 201 202 list_for_each_entry(kvf, &kv->file_list, node) { 203 if (kvf->file != fd_file(f)) 204 continue; 205 206 list_del(&kvf->node); 207 #ifdef CONFIG_SPAPR_TCE_IOMMU 208 kvm_spapr_tce_release_vfio_group(dev->kvm, kvf); 209 #endif 210 kvm_vfio_file_set_kvm(kvf->file, NULL); 211 fput(kvf->file); 212 kfree(kvf); 213 ret = 0; 214 break; 215 } 216 217 kvm_vfio_update_coherency(dev); 218 219 mutex_unlock(&kv->lock); 220 return ret; 221 } 222 223 #ifdef CONFIG_SPAPR_TCE_IOMMU 224 static int kvm_vfio_file_set_spapr_tce(struct kvm_device *dev, 225 void __user *arg) 226 { 227 struct kvm_vfio_spapr_tce param; 228 struct kvm_vfio *kv = dev->private; 229 struct kvm_vfio_file *kvf; 230 int ret; 231 232 if (copy_from_user(¶m, arg, sizeof(struct kvm_vfio_spapr_tce))) 233 return -EFAULT; 234 235 CLASS(fd, f)(param.groupfd); 236 if (fd_empty(f)) 237 return -EBADF; 238 239 ret = -ENOENT; 240 241 mutex_lock(&kv->lock); 242 243 list_for_each_entry(kvf, &kv->file_list, node) { 244 if (kvf->file != fd_file(f)) 245 continue; 246 247 if (!kvf->iommu_group) { 248 kvf->iommu_group = kvm_vfio_file_iommu_group(kvf->file); 249 if (WARN_ON_ONCE(!kvf->iommu_group)) { 250 ret = -EIO; 251 goto err_fdput; 252 } 253 } 254 255 ret = kvm_spapr_tce_attach_iommu_group(dev->kvm, param.tablefd, 256 kvf->iommu_group); 257 break; 258 } 259 260 err_fdput: 261 mutex_unlock(&kv->lock); 262 return ret; 263 } 264 #endif 265 266 static int kvm_vfio_set_file(struct kvm_device *dev, long attr, 267 void __user *arg) 268 { 269 int32_t __user *argp = arg; 270 int32_t fd; 271 272 switch (attr) { 273 case KVM_DEV_VFIO_FILE_ADD: 274 if (get_user(fd, argp)) 275 return -EFAULT; 276 return kvm_vfio_file_add(dev, fd); 277 278 case KVM_DEV_VFIO_FILE_DEL: 279 if (get_user(fd, argp)) 280 return -EFAULT; 281 return kvm_vfio_file_del(dev, fd); 282 283 #ifdef CONFIG_SPAPR_TCE_IOMMU 284 case KVM_DEV_VFIO_GROUP_SET_SPAPR_TCE: 285 return kvm_vfio_file_set_spapr_tce(dev, arg); 286 #endif 287 } 288 289 return -ENXIO; 290 } 291 292 static int kvm_vfio_set_attr(struct kvm_device *dev, 293 struct kvm_device_attr *attr) 294 { 295 switch (attr->group) { 296 case KVM_DEV_VFIO_FILE: 297 return kvm_vfio_set_file(dev, attr->attr, 298 u64_to_user_ptr(attr->addr)); 299 } 300 301 return -ENXIO; 302 } 303 304 static int kvm_vfio_has_attr(struct kvm_device *dev, 305 struct kvm_device_attr *attr) 306 { 307 switch (attr->group) { 308 case KVM_DEV_VFIO_FILE: 309 switch (attr->attr) { 310 case KVM_DEV_VFIO_FILE_ADD: 311 case KVM_DEV_VFIO_FILE_DEL: 312 #ifdef CONFIG_SPAPR_TCE_IOMMU 313 case KVM_DEV_VFIO_GROUP_SET_SPAPR_TCE: 314 #endif 315 return 0; 316 } 317 318 break; 319 } 320 321 return -ENXIO; 322 } 323 324 static void kvm_vfio_release(struct kvm_device *dev) 325 { 326 struct kvm_vfio *kv = dev->private; 327 struct kvm_vfio_file *kvf, *tmp; 328 329 list_for_each_entry_safe(kvf, tmp, &kv->file_list, node) { 330 #ifdef CONFIG_SPAPR_TCE_IOMMU 331 kvm_spapr_tce_release_vfio_group(dev->kvm, kvf); 332 #endif 333 kvm_vfio_file_set_kvm(kvf->file, NULL); 334 fput(kvf->file); 335 list_del(&kvf->node); 336 kfree(kvf); 337 } 338 339 kvm_vfio_update_coherency(dev); 340 341 kfree(kv); 342 kfree(dev); /* alloc by kvm_ioctl_create_device, free by .release */ 343 } 344 345 static int kvm_vfio_create(struct kvm_device *dev, u32 type); 346 347 static const struct kvm_device_ops kvm_vfio_ops = { 348 .name = "kvm-vfio", 349 .create = kvm_vfio_create, 350 .release = kvm_vfio_release, 351 .set_attr = kvm_vfio_set_attr, 352 .has_attr = kvm_vfio_has_attr, 353 }; 354 355 static int kvm_vfio_create(struct kvm_device *dev, u32 type) 356 { 357 struct kvm_device *tmp; 358 struct kvm_vfio *kv; 359 360 lockdep_assert_held(&dev->kvm->lock); 361 362 /* Only one VFIO "device" per VM */ 363 list_for_each_entry(tmp, &dev->kvm->devices, vm_node) 364 if (tmp->ops == &kvm_vfio_ops) 365 return -EBUSY; 366 367 kv = kzalloc(sizeof(*kv), GFP_KERNEL_ACCOUNT); 368 if (!kv) 369 return -ENOMEM; 370 371 INIT_LIST_HEAD(&kv->file_list); 372 mutex_init(&kv->lock); 373 374 dev->private = kv; 375 376 return 0; 377 } 378 379 int kvm_vfio_ops_init(void) 380 { 381 return kvm_register_device_ops(&kvm_vfio_ops, KVM_DEV_TYPE_VFIO); 382 } 383 384 void kvm_vfio_ops_exit(void) 385 { 386 kvm_unregister_device_ops(KVM_DEV_TYPE_VFIO); 387 } 388