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/pci.h>
  29 #include <linux/dmar.h>
  30 #include <linux/iommu.h>
  31 #include <linux/intel-iommu.h>
  32
  33 static int kvm_iommu_unmap_memslots(struct kvm *kvm);
  34 static void kvm_iommu_put_pages(struct kvm *kvm,
  35                                 gfn_t base_gfn, unsigned long npages);
  36
  37 static pfn_t kvm_pin_pages(struct kvm *kvm, struct kvm_memory_slot *slot,
  38                            gfn_t gfn, unsigned long size)
  39 {
  40         gfn_t end_gfn;
  41         pfn_t pfn;
  42
  43         pfn     = gfn_to_pfn_memslot(kvm, slot, gfn);
  44         end_gfn = gfn + (size >> PAGE_SHIFT);
  45         gfn    += 1;
  46
  47         if (is_error_pfn(pfn))
  48                 return pfn;
  49
  50         while (gfn < end_gfn)
  51                 gfn_to_pfn_memslot(kvm, slot, gfn++);
  52
  53         return pfn;
  54 }
  55
  56 int kvm_iommu_map_pages(struct kvm *kvm, struct kvm_memory_slot *slot)
  57 {
  58         gfn_t gfn, end_gfn;
  59         pfn_t pfn;
  60         int r = 0;
  61         struct iommu_domain *domain = kvm->arch.iommu_domain;
  62         int flags;
  63
  64         /* check if iommu exists and in use */
  65         if (!domain)
  66                 return 0;
  67
  68         gfn     = slot->base_gfn;
  69         end_gfn = gfn + slot->npages;
  70
  71         flags = IOMMU_READ | IOMMU_WRITE;
  72         if (kvm->arch.iommu_flags & KVM_IOMMU_CACHE_COHERENCY)
  73                 flags |= IOMMU_CACHE;
  74
  75
  76         while (gfn < end_gfn) {
  77                 unsigned long page_size;
  78
  79                 /* Check if already mapped */
  80                 if (iommu_iova_to_phys(domain, gfn_to_gpa(gfn))) {
  81                         gfn += 1;
  82                         continue;
  83                 }
  84
  85                 /* Get the page size we could use to map */
  86                 page_size = kvm_host_page_size(kvm, gfn);
  87
  88                 /* Make sure the page_size does not exceed the memslot */
  89                 while ((gfn + (page_size >> PAGE_SHIFT)) > end_gfn)
  90                         page_size >>= 1;
  91
  92                 /* Make sure gfn is aligned to the page size we want to map */
  93                 while ((gfn << PAGE_SHIFT) & (page_size - 1))
  94                         page_size >>= 1;
  95
  96                 /*
  97                  * Pin all pages we are about to map in memory. This is
  98                  * important because we unmap and unpin in 4kb steps later.
  99                  */
 100                 pfn = kvm_pin_pages(kvm, slot, gfn, page_size);
 101                 if (is_error_pfn(pfn)) {
 102                         gfn += 1;
 103                         continue;
 104                 }
 105
 106                 /* Map into IO address space */
 107                 r = iommu_map(domain, gfn_to_gpa(gfn), pfn_to_hpa(pfn),
 108                               get_order(page_size), flags);
 109                 if (r) {
 110                         printk(KERN_ERR "kvm_iommu_map_address:"
 111                                "iommu failed to map pfn=%llx\n", pfn);
 112                         goto unmap_pages;
 113                 }
 114
 115                 gfn += page_size >> PAGE_SHIFT;
 116
 117
 118         }
 119
 120         return 0;
 121
 122 unmap_pages:
 123         kvm_iommu_put_pages(kvm, slot->base_gfn, gfn);
 124         return r;
 125 }
 126
 127 static int kvm_iommu_map_memslots(struct kvm *kvm)
 128 {
 129         int i, idx, r = 0;
 130         struct kvm_memslots *slots;
 131
 132         idx = srcu_read_lock(&kvm->srcu);
 133         slots = kvm_memslots(kvm);
 134
 135         for (i = 0; i < slots->nmemslots; i++) {
 136                 r = kvm_iommu_map_pages(kvm, &slots->memslots[i]);
 137                 if (r)
 138                         break;
 139         }
 140         srcu_read_unlock(&kvm->srcu, idx);
 141
 142         return r;
 143 }
 144
 145 int kvm_assign_device(struct kvm *kvm,
 146                       struct kvm_assigned_dev_kernel *assigned_dev)
 147 {
 148         struct pci_dev *pdev = NULL;
 149         struct iommu_domain *domain = kvm->arch.iommu_domain;
 150         int r, last_flags;
 151
 152         /* check if iommu exists and in use */
 153         if (!domain)
 154                 return 0;
 155
 156         pdev = assigned_dev->dev;
 157         if (pdev == NULL)
 158                 return -ENODEV;
 159
 160         r = iommu_attach_device(domain, &pdev->dev);
 161         if (r) {
 162                 printk(KERN_ERR "assign device %x:%x:%x.%x failed",
 163                         pci_domain_nr(pdev->bus),
 164                         pdev->bus->number,
 165                         PCI_SLOT(pdev->devfn),
 166                         PCI_FUNC(pdev->devfn));
 167                 return r;
 168         }
 169
 170         last_flags = kvm->arch.iommu_flags;
 171         if (iommu_domain_has_cap(kvm->arch.iommu_domain,
 172                                  IOMMU_CAP_CACHE_COHERENCY))
 173                 kvm->arch.iommu_flags |= KVM_IOMMU_CACHE_COHERENCY;
 174
 175         /* Check if need to update IOMMU page table for guest memory */
 176         if ((last_flags ^ kvm->arch.iommu_flags) ==
 177                         KVM_IOMMU_CACHE_COHERENCY) {
 178                 kvm_iommu_unmap_memslots(kvm);
 179                 r = kvm_iommu_map_memslots(kvm);
 180                 if (r)
 181                         goto out_unmap;
 182         }
 183
 184         printk(KERN_DEBUG "assign device %x:%x:%x.%x\n",
 185                 assigned_dev->host_segnr,
 186                 assigned_dev->host_busnr,
 187                 PCI_SLOT(assigned_dev->host_devfn),
 188                 PCI_FUNC(assigned_dev->host_devfn));
 189
 190         return 0;
 191 out_unmap:
 192         kvm_iommu_unmap_memslots(kvm);
 193         return r;
 194 }
 195
 196 int kvm_deassign_device(struct kvm *kvm,
 197                         struct kvm_assigned_dev_kernel *assigned_dev)
 198 {
 199         struct iommu_domain *domain = kvm->arch.iommu_domain;
 200         struct pci_dev *pdev = NULL;
 201
 202         /* check if iommu exists and in use */
 203         if (!domain)
 204                 return 0;
 205
 206         pdev = assigned_dev->dev;
 207         if (pdev == NULL)
 208                 return -ENODEV;
 209
 210         iommu_detach_device(domain, &pdev->dev);
 211
 212         printk(KERN_DEBUG "deassign device %x:%x:%x.%x\n",
 213                 assigned_dev->host_segnr,
 214                 assigned_dev->host_busnr,
 215                 PCI_SLOT(assigned_dev->host_devfn),
 216                 PCI_FUNC(assigned_dev->host_devfn));
 217
 218         return 0;
 219 }
 220
 221 int kvm_iommu_map_guest(struct kvm *kvm)
 222 {
 223         int r;
 224
 225         if (!iommu_found()) {
 226                 printk(KERN_ERR "%s: iommu not found\n", __func__);
 227                 return -ENODEV;
 228         }
 229
 230         kvm->arch.iommu_domain = iommu_domain_alloc();
 231         if (!kvm->arch.iommu_domain)
 232                 return -ENOMEM;
 233
 234         r = kvm_iommu_map_memslots(kvm);
 235         if (r)
 236                 goto out_unmap;
 237
 238         return 0;
 239
 240 out_unmap:
 241         kvm_iommu_unmap_memslots(kvm);
 242         return r;
 243 }
 244
 245 static void kvm_unpin_pages(struct kvm *kvm, pfn_t pfn, unsigned long npages)
 246 {
 247         unsigned long i;
 248
 249         for (i = 0; i < npages; ++i)
 250                 kvm_release_pfn_clean(pfn + i);
 251 }
 252
 253 static void kvm_iommu_put_pages(struct kvm *kvm,
 254                                 gfn_t base_gfn, unsigned long npages)
 255 {
 256         struct iommu_domain *domain;
 257         gfn_t end_gfn, gfn;
 258         pfn_t pfn;
 259         u64 phys;
 260
 261         domain  = kvm->arch.iommu_domain;
 262         end_gfn = base_gfn + npages;
 263         gfn     = base_gfn;
 264
 265         /* check if iommu exists and in use */
 266         if (!domain)
 267                 return;
 268
 269         while (gfn < end_gfn) {
 270                 unsigned long unmap_pages;
 271                 int order;
 272
 273                 /* Get physical address */
 274                 phys = iommu_iova_to_phys(domain, gfn_to_gpa(gfn));
 275                 pfn  = phys >> PAGE_SHIFT;
 276
 277                 /* Unmap address from IO address space */
 278                 order       = iommu_unmap(domain, gfn_to_gpa(gfn), 0);
 279                 unmap_pages = 1ULL << order;
 280
 281                 /* Unpin all pages we just unmapped to not leak any memory */
 282                 kvm_unpin_pages(kvm, pfn, unmap_pages);
 283
 284                 gfn += unmap_pages;
 285         }
 286 }
 287
 288 static int kvm_iommu_unmap_memslots(struct kvm *kvm)
 289 {
 290         int i, idx;
 291         struct kvm_memslots *slots;
 292
 293         idx = srcu_read_lock(&kvm->srcu);
 294         slots = kvm_memslots(kvm);
 295
 296         for (i = 0; i < slots->nmemslots; i++) {
 297                 kvm_iommu_put_pages(kvm, slots->memslots[i].base_gfn,
 298                                     slots->memslots[i].npages);
 299         }
 300         srcu_read_unlock(&kvm->srcu, idx);
 301
 302         return 0;
 303 }
 304
 305 int kvm_iommu_unmap_guest(struct kvm *kvm)
 306 {
 307         struct iommu_domain *domain = kvm->arch.iommu_domain;
 308
 309         /* check if iommu exists and in use */
 310         if (!domain)
 311                 return 0;
 312
 313         kvm_iommu_unmap_memslots(kvm);
 314         iommu_domain_free(domain);
 315         return 0;
 316 }