virt/kvm/iommu.c

   1 /*
   2  * Copyright (c) 2006, Intel Corporation.
   3  *
   4  * This program is free software; you can redistribute it and/or modify it
   5  * under the terms and conditions of the GNU General Public License,
   6  * version 2, as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope it will be useful, but WITHOUT
   9  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  10  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  11  * more details.
  12  *
  13  * You should have received a copy of the GNU General Public License along with
  14  * this program; if not, write to the Free Software Foundation, Inc., 59 Temple
  15  * Place - Suite 330, Boston, MA 02111-1307 USA.
  16  *
  17  * Copyright (C) 2006-2008 Intel Corporation
  18  * Copyright IBM Corporation, 2008
  19  * Copyright 2010 Red Hat, Inc. and/or its affiliates.
  20  *
  21  * Author: Allen M. Kay <allen.m.kay@intel.com>
  22  * Author: Weidong Han <weidong.han@intel.com>
  23  * Author: Ben-Ami Yassour <benami@il.ibm.com>
  24  */
  25
  26 #include <linux/list.h>
  27 #include <linux/kvm_host.h>
  28 #include <linux/module.h>
  29 #include <linux/pci.h>
  30 #include <linux/stat.h>
  31 #include <linux/dmar.h>
  32 #include <linux/iommu.h>
  33 #include <linux/intel-iommu.h>
  34
  35 static bool allow_unsafe_assigned_interrupts;
  36 module_param_named(allow_unsafe_assigned_interrupts,
  37                    allow_unsafe_assigned_interrupts, bool, S_IRUGO | S_IWUSR);
  38 MODULE_PARM_DESC(allow_unsafe_assigned_interrupts,
  39  "Enable device assignment on platforms without interrupt remapping support.");
  40
  41 static int kvm_iommu_unmap_memslots(struct kvm *kvm);
  42 static void kvm_iommu_put_pages(struct kvm *kvm,
  43                                 gfn_t base_gfn, unsigned long npages);
  44
  45 static pfn_t kvm_pin_pages(struct kvm_memory_slot *slot, gfn_t gfn,
  46                            unsigned long size)
  47 {
  48         gfn_t end_gfn;
  49         pfn_t pfn;
  50
  51         pfn     = gfn_to_pfn_memslot(slot, gfn);
  52         end_gfn = gfn + (size >> PAGE_SHIFT);
  53         gfn    += 1;
  54
  55         if (is_error_noslot_pfn(pfn))
  56                 return pfn;
  57
  58         while (gfn < end_gfn)
  59                 gfn_to_pfn_memslot(slot, gfn++);
  60
  61         return pfn;
  62 }
  63
  64 static void kvm_unpin_pages(struct kvm *kvm, pfn_t pfn, unsigned long npages)
  65 {
  66         unsigned long i;
  67
  68         for (i = 0; i < npages; ++i)
  69                 kvm_release_pfn_clean(pfn + i);
  70 }
  71
  72 int kvm_iommu_map_pages(struct kvm *kvm, struct kvm_memory_slot *slot)
  73 {
  74         gfn_t gfn, end_gfn;
  75         pfn_t pfn;
  76         int r = 0;
  77         struct iommu_domain *domain = kvm->arch.iommu_domain;
  78         int flags;
  79
  80         /* check if iommu exists and in use */
  81         if (!domain)
  82                 return 0;
  83
  84         gfn     = slot->base_gfn;
  85         end_gfn = gfn + slot->npages;
  86
  87         flags = IOMMU_READ;
  88         if (!(slot->flags & KVM_MEM_READONLY))
  89                 flags |= IOMMU_WRITE;
  90         if (!kvm->arch.iommu_noncoherent)
  91                 flags |= IOMMU_CACHE;
  92
  93
  94         while (gfn < end_gfn) {
  95                 unsigned long page_size;
  96
  97                 /* Check if already mapped */
  98                 if (iommu_iova_to_phys(domain, gfn_to_gpa(gfn))) {
  99                         gfn += 1;
 100                         continue;
 101                 }
 102
 103                 /* Get the page size we could use to map */
 104                 page_size = kvm_host_page_size(kvm, gfn);
 105
 106                 /* Make sure the page_size does not exceed the memslot */
 107                 while ((gfn + (page_size >> PAGE_SHIFT)) > end_gfn)
 108                         page_size >>= 1;
 109
 110                 /* Make sure gfn is aligned to the page size we want to map */
 111                 while ((gfn << PAGE_SHIFT) & (page_size - 1))
 112                         page_size >>= 1;
 113
 114                 /* Make sure hva is aligned to the page size we want to map */
 115                 while (__gfn_to_hva_memslot(slot, gfn) & (page_size - 1))
 116                         page_size >>= 1;
 117
 118                 /*
 119                  * Pin all pages we are about to map in memory. This is
 120                  * important because we unmap and unpin in 4kb steps later.
 121                  */
 122                 pfn = kvm_pin_pages(slot, gfn, page_size);
 123                 if (is_error_noslot_pfn(pfn)) {
 124                         gfn += 1;
 125                         continue;
 126                 }
 127
 128                 /* Map into IO address space */
 129                 r = iommu_map(domain, gfn_to_gpa(gfn), pfn_to_hpa(pfn),
 130                               page_size, flags);
 131                 if (r) {
 132                         printk(KERN_ERR "kvm_iommu_map_address:"
 133                                "iommu failed to map pfn=%llx\n", pfn);
 134                         kvm_unpin_pages(kvm, pfn, page_size);
 135                         goto unmap_pages;
 136                 }
 137
 138                 gfn += page_size >> PAGE_SHIFT;
 139
 140
 141         }
 142
 143         return 0;
 144
 145 unmap_pages:
 146         kvm_iommu_put_pages(kvm, slot->base_gfn, gfn - slot->base_gfn);
 147         return r;
 148 }
 149
 150 static int kvm_iommu_map_memslots(struct kvm *kvm)
 151 {
 152         int idx, r = 0;
 153         struct kvm_memslots *slots;
 154         struct kvm_memory_slot *memslot;
 155
 156         if (kvm->arch.iommu_noncoherent)
 157                 kvm_arch_register_noncoherent_dma(kvm);
 158
 159         idx = srcu_read_lock(&kvm->srcu);
 160         slots = kvm_memslots(kvm);
 161
 162         kvm_for_each_memslot(memslot, slots) {
 163                 r = kvm_iommu_map_pages(kvm, memslot);
 164                 if (r)
 165                         break;
 166         }
 167         srcu_read_unlock(&kvm->srcu, idx);
 168
 169         return r;
 170 }
 171
 172 int kvm_assign_device(struct kvm *kvm,
 173                       struct kvm_assigned_dev_kernel *assigned_dev)
 174 {
 175         struct pci_dev *pdev = NULL;
 176         struct iommu_domain *domain = kvm->arch.iommu_domain;
 177         int r;
 178         bool noncoherent;
 179
 180         /* check if iommu exists and in use */
 181         if (!domain)
 182                 return 0;
 183
 184         pdev = assigned_dev->dev;
 185         if (pdev == NULL)
 186                 return -ENODEV;
 187
 188         r = iommu_attach_device(domain, &pdev->dev);
 189         if (r) {
 190                 dev_err(&pdev->dev, "kvm assign device failed ret %d", r);
 191                 return r;
 192         }
 193
 194         noncoherent = !iommu_domain_has_cap(kvm->arch.iommu_domain,
 195                                             IOMMU_CAP_CACHE_COHERENCY);
 196
 197         /* Check if need to update IOMMU page table for guest memory */
 198         if (noncoherent != kvm->arch.iommu_noncoherent) {
 199                 kvm_iommu_unmap_memslots(kvm);
 200                 kvm->arch.iommu_noncoherent = noncoherent;
 201                 r = kvm_iommu_map_memslots(kvm);
 202                 if (r)
 203                         goto out_unmap;
 204         }
 205
 206         pdev->dev_flags |= PCI_DEV_FLAGS_ASSIGNED;
 207
 208         dev_info(&pdev->dev, "kvm assign device\n");
 209
 210         return 0;
 211 out_unmap:
 212         kvm_iommu_unmap_memslots(kvm);
 213         return r;
 214 }
 215
 216 int kvm_deassign_device(struct kvm *kvm,
 217                         struct kvm_assigned_dev_kernel *assigned_dev)
 218 {
 219         struct iommu_domain *domain = kvm->arch.iommu_domain;
 220         struct pci_dev *pdev = NULL;
 221
 222         /* check if iommu exists and in use */
 223         if (!domain)
 224                 return 0;
 225
 226         pdev = assigned_dev->dev;
 227         if (pdev == NULL)
 228                 return -ENODEV;
 229
 230         iommu_detach_device(domain, &pdev->dev);
 231
 232         pdev->dev_flags &= ~PCI_DEV_FLAGS_ASSIGNED;
 233
 234         dev_info(&pdev->dev, "kvm deassign device\n");
 235
 236         return 0;
 237 }
 238
 239 int kvm_iommu_map_guest(struct kvm *kvm)
 240 {
 241         int r;
 242
 243         if (!iommu_present(&pci_bus_type)) {
 244                 printk(KERN_ERR "%s: iommu not found\n", __func__);
 245                 return -ENODEV;
 246         }
 247
 248         mutex_lock(&kvm->slots_lock);
 249
 250         kvm->arch.iommu_domain = iommu_domain_alloc(&pci_bus_type);
 251         if (!kvm->arch.iommu_domain) {
 252                 r = -ENOMEM;
 253                 goto out_unlock;
 254         }
 255
 256         if (!allow_unsafe_assigned_interrupts &&
 257             !iommu_domain_has_cap(kvm->arch.iommu_domain,
 258                                   IOMMU_CAP_INTR_REMAP)) {
 259                 printk(KERN_WARNING "%s: No interrupt remapping support,"
 260                        " disallowing device assignment."
 261                        " Re-enble with \"allow_unsafe_assigned_interrupts=1\""
 262                        " module option.\n", __func__);
 263                 iommu_domain_free(kvm->arch.iommu_domain);
 264                 kvm->arch.iommu_domain = NULL;
 265                 r = -EPERM;
 266                 goto out_unlock;
 267         }
 268
 269         r = kvm_iommu_map_memslots(kvm);
 270         if (r)
 271                 kvm_iommu_unmap_memslots(kvm);
 272
 273 out_unlock:
 274         mutex_unlock(&kvm->slots_lock);
 275         return r;
 276 }
 277
 278 static void kvm_iommu_put_pages(struct kvm *kvm,
 279                                 gfn_t base_gfn, unsigned long npages)
 280 {
 281         struct iommu_domain *domain;
 282         gfn_t end_gfn, gfn;
 283         pfn_t pfn;
 284         u64 phys;
 285
 286         domain  = kvm->arch.iommu_domain;
 287         end_gfn = base_gfn + npages;
 288         gfn     = base_gfn;
 289
 290         /* check if iommu exists and in use */
 291         if (!domain)
 292                 return;
 293
 294         while (gfn < end_gfn) {
 295                 unsigned long unmap_pages;
 296                 size_t size;
 297
 298                 /* Get physical address */
 299                 phys = iommu_iova_to_phys(domain, gfn_to_gpa(gfn));
 300
 301                 if (!phys) {
 302                         gfn++;
 303                         continue;
 304                 }
 305
 306                 pfn  = phys >> PAGE_SHIFT;
 307
 308                 /* Unmap address from IO address space */
 309                 size       = iommu_unmap(domain, gfn_to_gpa(gfn), PAGE_SIZE);
 310                 unmap_pages = 1ULL << get_order(size);
 311
 312                 /* Unpin all pages we just unmapped to not leak any memory */
 313                 kvm_unpin_pages(kvm, pfn, unmap_pages);
 314
 315                 gfn += unmap_pages;
 316         }
 317 }
 318
 319 void kvm_iommu_unmap_pages(struct kvm *kvm, struct kvm_memory_slot *slot)
 320 {
 321         kvm_iommu_put_pages(kvm, slot->base_gfn, slot->npages);
 322 }
 323
 324 static int kvm_iommu_unmap_memslots(struct kvm *kvm)
 325 {
 326         int idx;
 327         struct kvm_memslots *slots;
 328         struct kvm_memory_slot *memslot;
 329
 330         idx = srcu_read_lock(&kvm->srcu);
 331         slots = kvm_memslots(kvm);
 332
 333         kvm_for_each_memslot(memslot, slots)
 334                 kvm_iommu_unmap_pages(kvm, memslot);
 335
 336         srcu_read_unlock(&kvm->srcu, idx);
 337
 338         if (kvm->arch.iommu_noncoherent)
 339                 kvm_arch_unregister_noncoherent_dma(kvm);
 340
 341         return 0;
 342 }
 343
 344 int kvm_iommu_unmap_guest(struct kvm *kvm)
 345 {
 346         struct iommu_domain *domain = kvm->arch.iommu_domain;
 347
 348         /* check if iommu exists and in use */
 349         if (!domain)
 350                 return 0;
 351
 352         mutex_lock(&kvm->slots_lock);
 353         kvm_iommu_unmap_memslots(kvm);
 354         kvm->arch.iommu_domain = NULL;
 355         kvm->arch.iommu_noncoherent = false;
 356         mutex_unlock(&kvm->slots_lock);
 357
 358         iommu_domain_free(domain);
 359         return 0;
 360 }