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#include "assigned-dev.h"
 35
 36static bool allow_unsafe_assigned_interrupts;
 37module_param_named(allow_unsafe_assigned_interrupts,
 38		   allow_unsafe_assigned_interrupts, bool, S_IRUGO | S_IWUSR);
 39MODULE_PARM_DESC(allow_unsafe_assigned_interrupts,
 40 "Enable device assignment on platforms without interrupt remapping support.");
 41
 42static int kvm_iommu_unmap_memslots(struct kvm *kvm);
 43static void kvm_iommu_put_pages(struct kvm *kvm,
 44				gfn_t base_gfn, unsigned long npages);
 45
 46static kvm_pfn_t kvm_pin_pages(struct kvm_memory_slot *slot, gfn_t gfn,
 47			   unsigned long npages)
 48{
 49	gfn_t end_gfn;
 50	kvm_pfn_t pfn;
 51
 52	pfn     = gfn_to_pfn_memslot(slot, gfn);
 53	end_gfn = gfn + npages;
 54	gfn    += 1;
 55
 56	if (is_error_noslot_pfn(pfn))
 57		return pfn;
 58
 59	while (gfn < end_gfn)
 60		gfn_to_pfn_memslot(slot, gfn++);
 61
 62	return pfn;
 63}
 64
 65static void kvm_unpin_pages(struct kvm *kvm, kvm_pfn_t pfn,
 66		unsigned long npages)
 67{
 68	unsigned long i;
 69
 70	for (i = 0; i < npages; ++i)
 71		kvm_release_pfn_clean(pfn + i);
 72}
 73
 74int kvm_iommu_map_pages(struct kvm *kvm, struct kvm_memory_slot *slot)
 75{
 76	gfn_t gfn, end_gfn;
 77	kvm_pfn_t pfn;
 78	int r = 0;
 79	struct iommu_domain *domain = kvm->arch.iommu_domain;
 80	int flags;
 81
 82	/* check if iommu exists and in use */
 83	if (!domain)
 84		return 0;
 85
 86	gfn     = slot->base_gfn;
 87	end_gfn = gfn + slot->npages;
 88
 89	flags = IOMMU_READ;
 90	if (!(slot->flags & KVM_MEM_READONLY))
 91		flags |= IOMMU_WRITE;
 92	if (!kvm->arch.iommu_noncoherent)
 93		flags |= IOMMU_CACHE;
 94
 95
 96	while (gfn < end_gfn) {
 97		unsigned long page_size;
 98
 99		/* Check if already mapped */
100		if (iommu_iova_to_phys(domain, gfn_to_gpa(gfn))) {
101			gfn += 1;
102			continue;
103		}
104
105		/* Get the page size we could use to map */
106		page_size = kvm_host_page_size(kvm, gfn);
107
108		/* Make sure the page_size does not exceed the memslot */
109		while ((gfn + (page_size >> PAGE_SHIFT)) > end_gfn)
110			page_size >>= 1;
111
112		/* Make sure gfn is aligned to the page size we want to map */
113		while ((gfn << PAGE_SHIFT) & (page_size - 1))
114			page_size >>= 1;
115
116		/* Make sure hva is aligned to the page size we want to map */
117		while (__gfn_to_hva_memslot(slot, gfn) & (page_size - 1))
118			page_size >>= 1;
119
120		/*
121		 * Pin all pages we are about to map in memory. This is
122		 * important because we unmap and unpin in 4kb steps later.
123		 */
124		pfn = kvm_pin_pages(slot, gfn, page_size >> PAGE_SHIFT);
125		if (is_error_noslot_pfn(pfn)) {
126			gfn += 1;
127			continue;
128		}
129
130		/* Map into IO address space */
131		r = iommu_map(domain, gfn_to_gpa(gfn), pfn_to_hpa(pfn),
132			      page_size, flags);
133		if (r) {
134			printk(KERN_ERR "kvm_iommu_map_address:"
135			       "iommu failed to map pfn=%llx\n", pfn);
136			kvm_unpin_pages(kvm, pfn, page_size >> PAGE_SHIFT);
137			goto unmap_pages;
138		}
139
140		gfn += page_size >> PAGE_SHIFT;
141
142		cond_resched();
143	}
144
145	return 0;
146
147unmap_pages:
148	kvm_iommu_put_pages(kvm, slot->base_gfn, gfn - slot->base_gfn);
149	return r;
150}
151
152static int kvm_iommu_map_memslots(struct kvm *kvm)
153{
154	int idx, r = 0;
155	struct kvm_memslots *slots;
156	struct kvm_memory_slot *memslot;
157
158	if (kvm->arch.iommu_noncoherent)
159		kvm_arch_register_noncoherent_dma(kvm);
160
161	idx = srcu_read_lock(&kvm->srcu);
162	slots = kvm_memslots(kvm);
163
164	kvm_for_each_memslot(memslot, slots) {
165		r = kvm_iommu_map_pages(kvm, memslot);
166		if (r)
167			break;
168	}
169	srcu_read_unlock(&kvm->srcu, idx);
170
171	return r;
172}
173
174int kvm_assign_device(struct kvm *kvm, struct pci_dev *pdev)
175{
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	if (pdev == NULL)
185		return -ENODEV;
186
187	r = iommu_attach_device(domain, &pdev->dev);
188	if (r) {
189		dev_err(&pdev->dev, "kvm assign device failed ret %d", r);
190		return r;
191	}
192
193	noncoherent = !iommu_capable(&pci_bus_type, IOMMU_CAP_CACHE_COHERENCY);
194
195	/* Check if need to update IOMMU page table for guest memory */
196	if (noncoherent != kvm->arch.iommu_noncoherent) {
197		kvm_iommu_unmap_memslots(kvm);
198		kvm->arch.iommu_noncoherent = noncoherent;
199		r = kvm_iommu_map_memslots(kvm);
200		if (r)
201			goto out_unmap;
202	}
203
204	kvm_arch_start_assignment(kvm);
205	pci_set_dev_assigned(pdev);
206
207	dev_info(&pdev->dev, "kvm assign device\n");
208
209	return 0;
210out_unmap:
211	kvm_iommu_unmap_memslots(kvm);
212	return r;
213}
214
215int kvm_deassign_device(struct kvm *kvm, struct pci_dev *pdev)
216{
217	struct iommu_domain *domain = kvm->arch.iommu_domain;
218
219	/* check if iommu exists and in use */
220	if (!domain)
221		return 0;
222
223	if (pdev == NULL)
224		return -ENODEV;
225
226	iommu_detach_device(domain, &pdev->dev);
227
228	pci_clear_dev_assigned(pdev);
229	kvm_arch_end_assignment(kvm);
230
231	dev_info(&pdev->dev, "kvm deassign device\n");
232
233	return 0;
234}
235
236int kvm_iommu_map_guest(struct kvm *kvm)
237{
238	int r;
239
240	if (!iommu_present(&pci_bus_type)) {
241		printk(KERN_ERR "%s: iommu not found\n", __func__);
242		return -ENODEV;
243	}
244
245	mutex_lock(&kvm->slots_lock);
246
247	kvm->arch.iommu_domain = iommu_domain_alloc(&pci_bus_type);
248	if (!kvm->arch.iommu_domain) {
249		r = -ENOMEM;
250		goto out_unlock;
251	}
252
253	if (!allow_unsafe_assigned_interrupts &&
254	    !iommu_capable(&pci_bus_type, 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
269out_unlock:
270	mutex_unlock(&kvm->slots_lock);
271	return r;
272}
273
274static void kvm_iommu_put_pages(struct kvm *kvm,
275				gfn_t base_gfn, unsigned long npages)
276{
277	struct iommu_domain *domain;
278	gfn_t end_gfn, gfn;
279	kvm_pfn_t pfn;
280	u64 phys;
281
282	domain  = kvm->arch.iommu_domain;
283	end_gfn = base_gfn + npages;
284	gfn     = base_gfn;
285
286	/* check if iommu exists and in use */
287	if (!domain)
288		return;
289
290	while (gfn < end_gfn) {
291		unsigned long unmap_pages;
292		size_t size;
293
294		/* Get physical address */
295		phys = iommu_iova_to_phys(domain, gfn_to_gpa(gfn));
296
297		if (!phys) {
298			gfn++;
299			continue;
300		}
301
302		pfn  = phys >> PAGE_SHIFT;
303
304		/* Unmap address from IO address space */
305		size       = iommu_unmap(domain, gfn_to_gpa(gfn), PAGE_SIZE);
306		unmap_pages = 1ULL << get_order(size);
307
308		/* Unpin all pages we just unmapped to not leak any memory */
309		kvm_unpin_pages(kvm, pfn, unmap_pages);
310
311		gfn += unmap_pages;
312
313		cond_resched();
314	}
315}
316
317void kvm_iommu_unmap_pages(struct kvm *kvm, struct kvm_memory_slot *slot)
318{
319	kvm_iommu_put_pages(kvm, slot->base_gfn, slot->npages);
320}
321
322static int kvm_iommu_unmap_memslots(struct kvm *kvm)
323{
324	int idx;
325	struct kvm_memslots *slots;
326	struct kvm_memory_slot *memslot;
327
328	idx = srcu_read_lock(&kvm->srcu);
329	slots = kvm_memslots(kvm);
330
331	kvm_for_each_memslot(memslot, slots)
332		kvm_iommu_unmap_pages(kvm, memslot);
333
334	srcu_read_unlock(&kvm->srcu, idx);
335
336	if (kvm->arch.iommu_noncoherent)
337		kvm_arch_unregister_noncoherent_dma(kvm);
338
339	return 0;
340}
341
342int kvm_iommu_unmap_guest(struct kvm *kvm)
343{
344	struct iommu_domain *domain = kvm->arch.iommu_domain;
345
346	/* check if iommu exists and in use */
347	if (!domain)
348		return 0;
349
350	mutex_lock(&kvm->slots_lock);
351	kvm_iommu_unmap_memslots(kvm);
352	kvm->arch.iommu_domain = NULL;
353	kvm->arch.iommu_noncoherent = false;
354	mutex_unlock(&kvm->slots_lock);
355
356	iommu_domain_free(domain);
357	return 0;
358}