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TOMOYO Linux Cross Reference
Linux/virt/kvm/iommu.c

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

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