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_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 int kvm_iommu_map_pages(struct kvm *kvm, struct kvm_memory_slot *slot)
  65 {
  66         gfn_t gfn, end_gfn;
  67         pfn_t pfn;
  68         int r = 0;
  69         struct iommu_domain *domain = kvm->arch.iommu_domain;
  70         int flags;
  71
  72         /* check if iommu exists and in use */
  73         if (!domain)
  74                 return 0;
  75
  76         gfn     = slot->base_gfn;
  77         end_gfn = gfn + slot->npages;
  78
  79         flags = IOMMU_READ | IOMMU_WRITE;
  80         if (kvm->arch.iommu_flags & KVM_IOMMU_CACHE_COHERENCY)
  81                 flags |= IOMMU_CACHE;
  82
  83
  84         while (gfn < end_gfn) {
  85                 unsigned long page_size;
  86
  87                 /* Check if already mapped */
  88                 if (iommu_iova_to_phys(domain, gfn_to_gpa(gfn))) {
  89                         gfn += 1;
  90                         continue;
  91                 }
  92
  93                 /* Get the page size we could use to map */
  94                 page_size = kvm_host_page_size(kvm, gfn);
  95
  96                 /* Make sure the page_size does not exceed the memslot */
  97                 while ((gfn + (page_size >> PAGE_SHIFT)) > end_gfn)
  98                         page_size >>= 1;
  99
 100                 /* Make sure gfn is aligned to the page size we want to map */
 101                 while ((gfn << PAGE_SHIFT) & (page_size - 1))
 102                         page_size >>= 1;
 103
 104                 /*
 105                  * Pin all pages we are about to map in memory. This is
 106                  * important because we unmap and unpin in 4kb steps later.
 107                  */
 108                 pfn = kvm_pin_pages(slot, gfn, page_size);
 109                 if (is_error_pfn(pfn)) {
 110                         kvm_release_pfn_clean(pfn);
 111                         gfn += 1;
 112                         continue;
 113                 }
 114
 115                 /* Map into IO address space */
 116                 r = iommu_map(domain, gfn_to_gpa(gfn), pfn_to_hpa(pfn),
 117                               page_size, flags);
 118                 if (r) {
 119                         printk(KERN_ERR "kvm_iommu_map_address:"
 120                                "iommu failed to map pfn=%llx\n", pfn);
 121                         goto unmap_pages;
 122                 }
 123
 124                 gfn += page_size >> PAGE_SHIFT;
 125
 126
 127         }
 128
 129         return 0;
 130
 131 unmap_pages:
 132         kvm_iommu_put_pages(kvm, slot->base_gfn, gfn);
 133         return r;
 134 }
 135
 136 static int kvm_iommu_map_memslots(struct kvm *kvm)
 137 {
 138         int idx, r = 0;
 139         struct kvm_memslots *slots;
 140         struct kvm_memory_slot *memslot;
 141
 142         idx = srcu_read_lock(&kvm->srcu);
 143         slots = kvm_memslots(kvm);
 144
 145         kvm_for_each_memslot(memslot, slots) {
 146                 r = kvm_iommu_map_pages(kvm, memslot);
 147                 if (r)
 148                         break;
 149         }
 150         srcu_read_unlock(&kvm->srcu, idx);
 151
 152         return r;
 153 }
 154
 155 int kvm_assign_device(struct kvm *kvm,
 156                       struct kvm_assigned_dev_kernel *assigned_dev)
 157 {
 158         struct pci_dev *pdev = NULL;
 159         struct iommu_domain *domain = kvm->arch.iommu_domain;
 160         int r, last_flags;
 161
 162         /* check if iommu exists and in use */
 163         if (!domain)
 164                 return 0;
 165
 166         pdev = assigned_dev->dev;
 167         if (pdev == NULL)
 168                 return -ENODEV;
 169
 170         r = iommu_attach_device(domain, &pdev->dev);
 171         if (r) {
 172                 printk(KERN_ERR "assign device %x:%x:%x.%x failed",
 173                         pci_domain_nr(pdev->bus),
 174                         pdev->bus->number,
 175                         PCI_SLOT(pdev->devfn),
 176                         PCI_FUNC(pdev->devfn));
 177                 return r;
 178         }
 179
 180         last_flags = kvm->arch.iommu_flags;
 181         if (iommu_domain_has_cap(kvm->arch.iommu_domain,
 182                                  IOMMU_CAP_CACHE_COHERENCY))
 183                 kvm->arch.iommu_flags |= KVM_IOMMU_CACHE_COHERENCY;
 184
 185         /* Check if need to update IOMMU page table for guest memory */
 186         if ((last_flags ^ kvm->arch.iommu_flags) ==
 187                         KVM_IOMMU_CACHE_COHERENCY) {
 188                 kvm_iommu_unmap_memslots(kvm);
 189                 r = kvm_iommu_map_memslots(kvm);
 190                 if (r)
 191                         goto out_unmap;
 192         }
 193
 194         pdev->dev_flags |= PCI_DEV_FLAGS_ASSIGNED;
 195
 196         printk(KERN_DEBUG "assign device %x:%x:%x.%x\n",
 197                 assigned_dev->host_segnr,
 198                 assigned_dev->host_busnr,
 199                 PCI_SLOT(assigned_dev->host_devfn),
 200                 PCI_FUNC(assigned_dev->host_devfn));
 201
 202         return 0;
 203 out_unmap:
 204         kvm_iommu_unmap_memslots(kvm);
 205         return r;
 206 }
 207
 208 int kvm_deassign_device(struct kvm *kvm,
 209                         struct kvm_assigned_dev_kernel *assigned_dev)
 210 {
 211         struct iommu_domain *domain = kvm->arch.iommu_domain;
 212         struct pci_dev *pdev = NULL;
 213
 214         /* check if iommu exists and in use */
 215         if (!domain)
 216                 return 0;
 217
 218         pdev = assigned_dev->dev;
 219         if (pdev == NULL)
 220                 return -ENODEV;
 221
 222         iommu_detach_device(domain, &pdev->dev);
 223
 224         pdev->dev_flags &= ~PCI_DEV_FLAGS_ASSIGNED;
 225
 226         printk(KERN_DEBUG "deassign device %x:%x:%x.%x\n",
 227                 assigned_dev->host_segnr,
 228                 assigned_dev->host_busnr,
 229                 PCI_SLOT(assigned_dev->host_devfn),
 230                 PCI_FUNC(assigned_dev->host_devfn));
 231
 232         return 0;
 233 }
 234
 235 int kvm_iommu_map_guest(struct kvm *kvm)
 236 {
 237         int r;
 238
 239         if (!iommu_present(&pci_bus_type)) {
 240                 printk(KERN_ERR "%s: iommu not found\n", __func__);
 241                 return -ENODEV;
 242         }
 243
 244         mutex_lock(&kvm->slots_lock);
 245
 246         kvm->arch.iommu_domain = iommu_domain_alloc(&pci_bus_type);
 247         if (!kvm->arch.iommu_domain) {
 248                 r = -ENOMEM;
 249                 goto out_unlock;
 250         }
 251
 252         if (!allow_unsafe_assigned_interrupts &&
 253             !iommu_domain_has_cap(kvm->arch.iommu_domain,
 254                                   IOMMU_CAP_INTR_REMAP)) {
 255                 printk(KERN_WARNING "%s: No interrupt remapping support,"
 256                        " disallowing device assignment."
 257                        " Re-enble with \"allow_unsafe_assigned_interrupts=1\""
 258                        " module option.\n", __func__);
 259                 iommu_domain_free(kvm->arch.iommu_domain);
 260                 kvm->arch.iommu_domain = NULL;
 261                 r = -EPERM;
 262                 goto out_unlock;
 263         }
 264
 265         r = kvm_iommu_map_memslots(kvm);
 266         if (r)
 267                 kvm_iommu_unmap_memslots(kvm);
 268
 269 out_unlock:
 270         mutex_unlock(&kvm->slots_lock);
 271         return r;
 272 }
 273
 274 static void kvm_unpin_pages(struct kvm *kvm, pfn_t pfn, unsigned long npages)
 275 {
 276         unsigned long i;
 277
 278         for (i = 0; i < npages; ++i)
 279                 kvm_release_pfn_clean(pfn + i);
 280 }
 281
 282 static void kvm_iommu_put_pages(struct kvm *kvm,
 283                                 gfn_t base_gfn, unsigned long npages)
 284 {
 285         struct iommu_domain *domain;
 286         gfn_t end_gfn, gfn;
 287         pfn_t pfn;
 288         u64 phys;
 289
 290         domain  = kvm->arch.iommu_domain;
 291         end_gfn = base_gfn + npages;
 292         gfn     = base_gfn;
 293
 294         /* check if iommu exists and in use */
 295         if (!domain)
 296                 return;
 297
 298         while (gfn < end_gfn) {
 299                 unsigned long unmap_pages;
 300                 size_t size;
 301
 302                 /* Get physical address */
 303                 phys = iommu_iova_to_phys(domain, gfn_to_gpa(gfn));
 304
 305                 if (!phys) {
 306                         gfn++;
 307                         continue;
 308                 }
 309
 310                 pfn  = phys >> PAGE_SHIFT;
 311
 312                 /* Unmap address from IO address space */
 313                 size       = iommu_unmap(domain, gfn_to_gpa(gfn), PAGE_SIZE);
 314                 unmap_pages = 1ULL << get_order(size);
 315
 316                 /* Unpin all pages we just unmapped to not leak any memory */
 317                 kvm_unpin_pages(kvm, pfn, unmap_pages);
 318
 319                 gfn += unmap_pages;
 320         }
 321 }
 322
 323 void kvm_iommu_unmap_pages(struct kvm *kvm, struct kvm_memory_slot *slot)
 324 {
 325         kvm_iommu_put_pages(kvm, slot->base_gfn, slot->npages);
 326 }
 327
 328 static int kvm_iommu_unmap_memslots(struct kvm *kvm)
 329 {
 330         int idx;
 331         struct kvm_memslots *slots;
 332         struct kvm_memory_slot *memslot;
 333
 334         idx = srcu_read_lock(&kvm->srcu);
 335         slots = kvm_memslots(kvm);
 336
 337         kvm_for_each_memslot(memslot, slots)
 338                 kvm_iommu_unmap_pages(kvm, memslot);
 339
 340         srcu_read_unlock(&kvm->srcu, idx);
 341
 342         return 0;
 343 }
 344
 345 int kvm_iommu_unmap_guest(struct kvm *kvm)
 346 {
 347         struct iommu_domain *domain = kvm->arch.iommu_domain;
 348
 349         /* check if iommu exists and in use */
 350         if (!domain)
 351                 return 0;
 352
 353         mutex_lock(&kvm->slots_lock);
 354         kvm_iommu_unmap_memslots(kvm);
 355         kvm->arch.iommu_domain = NULL;
 356         mutex_unlock(&kvm->slots_lock);
 357
 358         iommu_domain_free(domain);
 359         return 0;
 360 }