xref: /linux/virt/kvm/kvm_main.c (revision 4dc7ccf7e9d9bca1989b840be9e8e84911387cf2)
1 /*
2  * Kernel-based Virtual Machine driver for Linux
3  *
4  * This module enables machines with Intel VT-x extensions to run virtual
5  * machines without emulation or binary translation.
6  *
7  * Copyright (C) 2006 Qumranet, Inc.
8  *
9  * Authors:
10  *   Avi Kivity   <avi@qumranet.com>
11  *   Yaniv Kamay  <yaniv@qumranet.com>
12  *
13  * This work is licensed under the terms of the GNU GPL, version 2.  See
14  * the COPYING file in the top-level directory.
15  *
16  */
17 
18 #include "iodev.h"
19 
20 #include <linux/kvm_host.h>
21 #include <linux/kvm.h>
22 #include <linux/module.h>
23 #include <linux/errno.h>
24 #include <linux/percpu.h>
25 #include <linux/mm.h>
26 #include <linux/miscdevice.h>
27 #include <linux/vmalloc.h>
28 #include <linux/reboot.h>
29 #include <linux/debugfs.h>
30 #include <linux/highmem.h>
31 #include <linux/file.h>
32 #include <linux/sysdev.h>
33 #include <linux/cpu.h>
34 #include <linux/sched.h>
35 #include <linux/cpumask.h>
36 #include <linux/smp.h>
37 #include <linux/anon_inodes.h>
38 #include <linux/profile.h>
39 #include <linux/kvm_para.h>
40 #include <linux/pagemap.h>
41 #include <linux/mman.h>
42 #include <linux/swap.h>
43 #include <linux/bitops.h>
44 #include <linux/spinlock.h>
45 #include <linux/compat.h>
46 #include <linux/srcu.h>
47 #include <linux/hugetlb.h>
48 #include <linux/slab.h>
49 
50 #include <asm/processor.h>
51 #include <asm/io.h>
52 #include <asm/uaccess.h>
53 #include <asm/pgtable.h>
54 #include <asm-generic/bitops/le.h>
55 
56 #include "coalesced_mmio.h"
57 
58 #define CREATE_TRACE_POINTS
59 #include <trace/events/kvm.h>
60 
61 MODULE_AUTHOR("Qumranet");
62 MODULE_LICENSE("GPL");
63 
64 /*
65  * Ordering of locks:
66  *
67  * 		kvm->lock --> kvm->slots_lock --> kvm->irq_lock
68  */
69 
70 DEFINE_SPINLOCK(kvm_lock);
71 LIST_HEAD(vm_list);
72 
73 static cpumask_var_t cpus_hardware_enabled;
74 static int kvm_usage_count = 0;
75 static atomic_t hardware_enable_failed;
76 
77 struct kmem_cache *kvm_vcpu_cache;
78 EXPORT_SYMBOL_GPL(kvm_vcpu_cache);
79 
80 static __read_mostly struct preempt_ops kvm_preempt_ops;
81 
82 struct dentry *kvm_debugfs_dir;
83 
84 static long kvm_vcpu_ioctl(struct file *file, unsigned int ioctl,
85 			   unsigned long arg);
86 static int hardware_enable_all(void);
87 static void hardware_disable_all(void);
88 
89 static void kvm_io_bus_destroy(struct kvm_io_bus *bus);
90 
91 static bool kvm_rebooting;
92 
93 static bool largepages_enabled = true;
94 
95 inline int kvm_is_mmio_pfn(pfn_t pfn)
96 {
97 	if (pfn_valid(pfn)) {
98 		struct page *page = compound_head(pfn_to_page(pfn));
99 		return PageReserved(page);
100 	}
101 
102 	return true;
103 }
104 
105 /*
106  * Switches to specified vcpu, until a matching vcpu_put()
107  */
108 void vcpu_load(struct kvm_vcpu *vcpu)
109 {
110 	int cpu;
111 
112 	mutex_lock(&vcpu->mutex);
113 	cpu = get_cpu();
114 	preempt_notifier_register(&vcpu->preempt_notifier);
115 	kvm_arch_vcpu_load(vcpu, cpu);
116 	put_cpu();
117 }
118 
119 void vcpu_put(struct kvm_vcpu *vcpu)
120 {
121 	preempt_disable();
122 	kvm_arch_vcpu_put(vcpu);
123 	preempt_notifier_unregister(&vcpu->preempt_notifier);
124 	preempt_enable();
125 	mutex_unlock(&vcpu->mutex);
126 }
127 
128 static void ack_flush(void *_completed)
129 {
130 }
131 
132 static bool make_all_cpus_request(struct kvm *kvm, unsigned int req)
133 {
134 	int i, cpu, me;
135 	cpumask_var_t cpus;
136 	bool called = true;
137 	struct kvm_vcpu *vcpu;
138 
139 	zalloc_cpumask_var(&cpus, GFP_ATOMIC);
140 
141 	raw_spin_lock(&kvm->requests_lock);
142 	me = smp_processor_id();
143 	kvm_for_each_vcpu(i, vcpu, kvm) {
144 		if (test_and_set_bit(req, &vcpu->requests))
145 			continue;
146 		cpu = vcpu->cpu;
147 		if (cpus != NULL && cpu != -1 && cpu != me)
148 			cpumask_set_cpu(cpu, cpus);
149 	}
150 	if (unlikely(cpus == NULL))
151 		smp_call_function_many(cpu_online_mask, ack_flush, NULL, 1);
152 	else if (!cpumask_empty(cpus))
153 		smp_call_function_many(cpus, ack_flush, NULL, 1);
154 	else
155 		called = false;
156 	raw_spin_unlock(&kvm->requests_lock);
157 	free_cpumask_var(cpus);
158 	return called;
159 }
160 
161 void kvm_flush_remote_tlbs(struct kvm *kvm)
162 {
163 	if (make_all_cpus_request(kvm, KVM_REQ_TLB_FLUSH))
164 		++kvm->stat.remote_tlb_flush;
165 }
166 
167 void kvm_reload_remote_mmus(struct kvm *kvm)
168 {
169 	make_all_cpus_request(kvm, KVM_REQ_MMU_RELOAD);
170 }
171 
172 int kvm_vcpu_init(struct kvm_vcpu *vcpu, struct kvm *kvm, unsigned id)
173 {
174 	struct page *page;
175 	int r;
176 
177 	mutex_init(&vcpu->mutex);
178 	vcpu->cpu = -1;
179 	vcpu->kvm = kvm;
180 	vcpu->vcpu_id = id;
181 	init_waitqueue_head(&vcpu->wq);
182 
183 	page = alloc_page(GFP_KERNEL | __GFP_ZERO);
184 	if (!page) {
185 		r = -ENOMEM;
186 		goto fail;
187 	}
188 	vcpu->run = page_address(page);
189 
190 	r = kvm_arch_vcpu_init(vcpu);
191 	if (r < 0)
192 		goto fail_free_run;
193 	return 0;
194 
195 fail_free_run:
196 	free_page((unsigned long)vcpu->run);
197 fail:
198 	return r;
199 }
200 EXPORT_SYMBOL_GPL(kvm_vcpu_init);
201 
202 void kvm_vcpu_uninit(struct kvm_vcpu *vcpu)
203 {
204 	kvm_arch_vcpu_uninit(vcpu);
205 	free_page((unsigned long)vcpu->run);
206 }
207 EXPORT_SYMBOL_GPL(kvm_vcpu_uninit);
208 
209 #if defined(CONFIG_MMU_NOTIFIER) && defined(KVM_ARCH_WANT_MMU_NOTIFIER)
210 static inline struct kvm *mmu_notifier_to_kvm(struct mmu_notifier *mn)
211 {
212 	return container_of(mn, struct kvm, mmu_notifier);
213 }
214 
215 static void kvm_mmu_notifier_invalidate_page(struct mmu_notifier *mn,
216 					     struct mm_struct *mm,
217 					     unsigned long address)
218 {
219 	struct kvm *kvm = mmu_notifier_to_kvm(mn);
220 	int need_tlb_flush, idx;
221 
222 	/*
223 	 * When ->invalidate_page runs, the linux pte has been zapped
224 	 * already but the page is still allocated until
225 	 * ->invalidate_page returns. So if we increase the sequence
226 	 * here the kvm page fault will notice if the spte can't be
227 	 * established because the page is going to be freed. If
228 	 * instead the kvm page fault establishes the spte before
229 	 * ->invalidate_page runs, kvm_unmap_hva will release it
230 	 * before returning.
231 	 *
232 	 * The sequence increase only need to be seen at spin_unlock
233 	 * time, and not at spin_lock time.
234 	 *
235 	 * Increasing the sequence after the spin_unlock would be
236 	 * unsafe because the kvm page fault could then establish the
237 	 * pte after kvm_unmap_hva returned, without noticing the page
238 	 * is going to be freed.
239 	 */
240 	idx = srcu_read_lock(&kvm->srcu);
241 	spin_lock(&kvm->mmu_lock);
242 	kvm->mmu_notifier_seq++;
243 	need_tlb_flush = kvm_unmap_hva(kvm, address);
244 	spin_unlock(&kvm->mmu_lock);
245 	srcu_read_unlock(&kvm->srcu, idx);
246 
247 	/* we've to flush the tlb before the pages can be freed */
248 	if (need_tlb_flush)
249 		kvm_flush_remote_tlbs(kvm);
250 
251 }
252 
253 static void kvm_mmu_notifier_change_pte(struct mmu_notifier *mn,
254 					struct mm_struct *mm,
255 					unsigned long address,
256 					pte_t pte)
257 {
258 	struct kvm *kvm = mmu_notifier_to_kvm(mn);
259 	int idx;
260 
261 	idx = srcu_read_lock(&kvm->srcu);
262 	spin_lock(&kvm->mmu_lock);
263 	kvm->mmu_notifier_seq++;
264 	kvm_set_spte_hva(kvm, address, pte);
265 	spin_unlock(&kvm->mmu_lock);
266 	srcu_read_unlock(&kvm->srcu, idx);
267 }
268 
269 static void kvm_mmu_notifier_invalidate_range_start(struct mmu_notifier *mn,
270 						    struct mm_struct *mm,
271 						    unsigned long start,
272 						    unsigned long end)
273 {
274 	struct kvm *kvm = mmu_notifier_to_kvm(mn);
275 	int need_tlb_flush = 0, idx;
276 
277 	idx = srcu_read_lock(&kvm->srcu);
278 	spin_lock(&kvm->mmu_lock);
279 	/*
280 	 * The count increase must become visible at unlock time as no
281 	 * spte can be established without taking the mmu_lock and
282 	 * count is also read inside the mmu_lock critical section.
283 	 */
284 	kvm->mmu_notifier_count++;
285 	for (; start < end; start += PAGE_SIZE)
286 		need_tlb_flush |= kvm_unmap_hva(kvm, start);
287 	spin_unlock(&kvm->mmu_lock);
288 	srcu_read_unlock(&kvm->srcu, idx);
289 
290 	/* we've to flush the tlb before the pages can be freed */
291 	if (need_tlb_flush)
292 		kvm_flush_remote_tlbs(kvm);
293 }
294 
295 static void kvm_mmu_notifier_invalidate_range_end(struct mmu_notifier *mn,
296 						  struct mm_struct *mm,
297 						  unsigned long start,
298 						  unsigned long end)
299 {
300 	struct kvm *kvm = mmu_notifier_to_kvm(mn);
301 
302 	spin_lock(&kvm->mmu_lock);
303 	/*
304 	 * This sequence increase will notify the kvm page fault that
305 	 * the page that is going to be mapped in the spte could have
306 	 * been freed.
307 	 */
308 	kvm->mmu_notifier_seq++;
309 	/*
310 	 * The above sequence increase must be visible before the
311 	 * below count decrease but both values are read by the kvm
312 	 * page fault under mmu_lock spinlock so we don't need to add
313 	 * a smb_wmb() here in between the two.
314 	 */
315 	kvm->mmu_notifier_count--;
316 	spin_unlock(&kvm->mmu_lock);
317 
318 	BUG_ON(kvm->mmu_notifier_count < 0);
319 }
320 
321 static int kvm_mmu_notifier_clear_flush_young(struct mmu_notifier *mn,
322 					      struct mm_struct *mm,
323 					      unsigned long address)
324 {
325 	struct kvm *kvm = mmu_notifier_to_kvm(mn);
326 	int young, idx;
327 
328 	idx = srcu_read_lock(&kvm->srcu);
329 	spin_lock(&kvm->mmu_lock);
330 	young = kvm_age_hva(kvm, address);
331 	spin_unlock(&kvm->mmu_lock);
332 	srcu_read_unlock(&kvm->srcu, idx);
333 
334 	if (young)
335 		kvm_flush_remote_tlbs(kvm);
336 
337 	return young;
338 }
339 
340 static void kvm_mmu_notifier_release(struct mmu_notifier *mn,
341 				     struct mm_struct *mm)
342 {
343 	struct kvm *kvm = mmu_notifier_to_kvm(mn);
344 	kvm_arch_flush_shadow(kvm);
345 }
346 
347 static const struct mmu_notifier_ops kvm_mmu_notifier_ops = {
348 	.invalidate_page	= kvm_mmu_notifier_invalidate_page,
349 	.invalidate_range_start	= kvm_mmu_notifier_invalidate_range_start,
350 	.invalidate_range_end	= kvm_mmu_notifier_invalidate_range_end,
351 	.clear_flush_young	= kvm_mmu_notifier_clear_flush_young,
352 	.change_pte		= kvm_mmu_notifier_change_pte,
353 	.release		= kvm_mmu_notifier_release,
354 };
355 
356 static int kvm_init_mmu_notifier(struct kvm *kvm)
357 {
358 	kvm->mmu_notifier.ops = &kvm_mmu_notifier_ops;
359 	return mmu_notifier_register(&kvm->mmu_notifier, current->mm);
360 }
361 
362 #else  /* !(CONFIG_MMU_NOTIFIER && KVM_ARCH_WANT_MMU_NOTIFIER) */
363 
364 static int kvm_init_mmu_notifier(struct kvm *kvm)
365 {
366 	return 0;
367 }
368 
369 #endif /* CONFIG_MMU_NOTIFIER && KVM_ARCH_WANT_MMU_NOTIFIER */
370 
371 static struct kvm *kvm_create_vm(void)
372 {
373 	int r = 0, i;
374 	struct kvm *kvm = kvm_arch_create_vm();
375 
376 	if (IS_ERR(kvm))
377 		goto out;
378 
379 	r = hardware_enable_all();
380 	if (r)
381 		goto out_err_nodisable;
382 
383 #ifdef CONFIG_HAVE_KVM_IRQCHIP
384 	INIT_HLIST_HEAD(&kvm->mask_notifier_list);
385 	INIT_HLIST_HEAD(&kvm->irq_ack_notifier_list);
386 #endif
387 
388 	r = -ENOMEM;
389 	kvm->memslots = kzalloc(sizeof(struct kvm_memslots), GFP_KERNEL);
390 	if (!kvm->memslots)
391 		goto out_err;
392 	if (init_srcu_struct(&kvm->srcu))
393 		goto out_err;
394 	for (i = 0; i < KVM_NR_BUSES; i++) {
395 		kvm->buses[i] = kzalloc(sizeof(struct kvm_io_bus),
396 					GFP_KERNEL);
397 		if (!kvm->buses[i]) {
398 			cleanup_srcu_struct(&kvm->srcu);
399 			goto out_err;
400 		}
401 	}
402 
403 	r = kvm_init_mmu_notifier(kvm);
404 	if (r) {
405 		cleanup_srcu_struct(&kvm->srcu);
406 		goto out_err;
407 	}
408 
409 	kvm->mm = current->mm;
410 	atomic_inc(&kvm->mm->mm_count);
411 	spin_lock_init(&kvm->mmu_lock);
412 	raw_spin_lock_init(&kvm->requests_lock);
413 	kvm_eventfd_init(kvm);
414 	mutex_init(&kvm->lock);
415 	mutex_init(&kvm->irq_lock);
416 	mutex_init(&kvm->slots_lock);
417 	atomic_set(&kvm->users_count, 1);
418 	spin_lock(&kvm_lock);
419 	list_add(&kvm->vm_list, &vm_list);
420 	spin_unlock(&kvm_lock);
421 #ifdef KVM_COALESCED_MMIO_PAGE_OFFSET
422 	kvm_coalesced_mmio_init(kvm);
423 #endif
424 out:
425 	return kvm;
426 
427 out_err:
428 	hardware_disable_all();
429 out_err_nodisable:
430 	for (i = 0; i < KVM_NR_BUSES; i++)
431 		kfree(kvm->buses[i]);
432 	kfree(kvm->memslots);
433 	kfree(kvm);
434 	return ERR_PTR(r);
435 }
436 
437 /*
438  * Free any memory in @free but not in @dont.
439  */
440 static void kvm_free_physmem_slot(struct kvm_memory_slot *free,
441 				  struct kvm_memory_slot *dont)
442 {
443 	int i;
444 
445 	if (!dont || free->rmap != dont->rmap)
446 		vfree(free->rmap);
447 
448 	if (!dont || free->dirty_bitmap != dont->dirty_bitmap)
449 		vfree(free->dirty_bitmap);
450 
451 
452 	for (i = 0; i < KVM_NR_PAGE_SIZES - 1; ++i) {
453 		if (!dont || free->lpage_info[i] != dont->lpage_info[i]) {
454 			vfree(free->lpage_info[i]);
455 			free->lpage_info[i] = NULL;
456 		}
457 	}
458 
459 	free->npages = 0;
460 	free->dirty_bitmap = NULL;
461 	free->rmap = NULL;
462 }
463 
464 void kvm_free_physmem(struct kvm *kvm)
465 {
466 	int i;
467 	struct kvm_memslots *slots = kvm->memslots;
468 
469 	for (i = 0; i < slots->nmemslots; ++i)
470 		kvm_free_physmem_slot(&slots->memslots[i], NULL);
471 
472 	kfree(kvm->memslots);
473 }
474 
475 static void kvm_destroy_vm(struct kvm *kvm)
476 {
477 	int i;
478 	struct mm_struct *mm = kvm->mm;
479 
480 	kvm_arch_sync_events(kvm);
481 	spin_lock(&kvm_lock);
482 	list_del(&kvm->vm_list);
483 	spin_unlock(&kvm_lock);
484 	kvm_free_irq_routing(kvm);
485 	for (i = 0; i < KVM_NR_BUSES; i++)
486 		kvm_io_bus_destroy(kvm->buses[i]);
487 	kvm_coalesced_mmio_free(kvm);
488 #if defined(CONFIG_MMU_NOTIFIER) && defined(KVM_ARCH_WANT_MMU_NOTIFIER)
489 	mmu_notifier_unregister(&kvm->mmu_notifier, kvm->mm);
490 #else
491 	kvm_arch_flush_shadow(kvm);
492 #endif
493 	kvm_arch_destroy_vm(kvm);
494 	hardware_disable_all();
495 	mmdrop(mm);
496 }
497 
498 void kvm_get_kvm(struct kvm *kvm)
499 {
500 	atomic_inc(&kvm->users_count);
501 }
502 EXPORT_SYMBOL_GPL(kvm_get_kvm);
503 
504 void kvm_put_kvm(struct kvm *kvm)
505 {
506 	if (atomic_dec_and_test(&kvm->users_count))
507 		kvm_destroy_vm(kvm);
508 }
509 EXPORT_SYMBOL_GPL(kvm_put_kvm);
510 
511 
512 static int kvm_vm_release(struct inode *inode, struct file *filp)
513 {
514 	struct kvm *kvm = filp->private_data;
515 
516 	kvm_irqfd_release(kvm);
517 
518 	kvm_put_kvm(kvm);
519 	return 0;
520 }
521 
522 /*
523  * Allocate some memory and give it an address in the guest physical address
524  * space.
525  *
526  * Discontiguous memory is allowed, mostly for framebuffers.
527  *
528  * Must be called holding mmap_sem for write.
529  */
530 int __kvm_set_memory_region(struct kvm *kvm,
531 			    struct kvm_userspace_memory_region *mem,
532 			    int user_alloc)
533 {
534 	int r, flush_shadow = 0;
535 	gfn_t base_gfn;
536 	unsigned long npages;
537 	unsigned long i;
538 	struct kvm_memory_slot *memslot;
539 	struct kvm_memory_slot old, new;
540 	struct kvm_memslots *slots, *old_memslots;
541 
542 	r = -EINVAL;
543 	/* General sanity checks */
544 	if (mem->memory_size & (PAGE_SIZE - 1))
545 		goto out;
546 	if (mem->guest_phys_addr & (PAGE_SIZE - 1))
547 		goto out;
548 	if (user_alloc && (mem->userspace_addr & (PAGE_SIZE - 1)))
549 		goto out;
550 	if (mem->slot >= KVM_MEMORY_SLOTS + KVM_PRIVATE_MEM_SLOTS)
551 		goto out;
552 	if (mem->guest_phys_addr + mem->memory_size < mem->guest_phys_addr)
553 		goto out;
554 
555 	memslot = &kvm->memslots->memslots[mem->slot];
556 	base_gfn = mem->guest_phys_addr >> PAGE_SHIFT;
557 	npages = mem->memory_size >> PAGE_SHIFT;
558 
559 	if (!npages)
560 		mem->flags &= ~KVM_MEM_LOG_DIRTY_PAGES;
561 
562 	new = old = *memslot;
563 
564 	new.base_gfn = base_gfn;
565 	new.npages = npages;
566 	new.flags = mem->flags;
567 
568 	/* Disallow changing a memory slot's size. */
569 	r = -EINVAL;
570 	if (npages && old.npages && npages != old.npages)
571 		goto out_free;
572 
573 	/* Check for overlaps */
574 	r = -EEXIST;
575 	for (i = 0; i < KVM_MEMORY_SLOTS; ++i) {
576 		struct kvm_memory_slot *s = &kvm->memslots->memslots[i];
577 
578 		if (s == memslot || !s->npages)
579 			continue;
580 		if (!((base_gfn + npages <= s->base_gfn) ||
581 		      (base_gfn >= s->base_gfn + s->npages)))
582 			goto out_free;
583 	}
584 
585 	/* Free page dirty bitmap if unneeded */
586 	if (!(new.flags & KVM_MEM_LOG_DIRTY_PAGES))
587 		new.dirty_bitmap = NULL;
588 
589 	r = -ENOMEM;
590 
591 	/* Allocate if a slot is being created */
592 #ifndef CONFIG_S390
593 	if (npages && !new.rmap) {
594 		new.rmap = vmalloc(npages * sizeof(struct page *));
595 
596 		if (!new.rmap)
597 			goto out_free;
598 
599 		memset(new.rmap, 0, npages * sizeof(*new.rmap));
600 
601 		new.user_alloc = user_alloc;
602 		new.userspace_addr = mem->userspace_addr;
603 	}
604 	if (!npages)
605 		goto skip_lpage;
606 
607 	for (i = 0; i < KVM_NR_PAGE_SIZES - 1; ++i) {
608 		unsigned long ugfn;
609 		unsigned long j;
610 		int lpages;
611 		int level = i + 2;
612 
613 		/* Avoid unused variable warning if no large pages */
614 		(void)level;
615 
616 		if (new.lpage_info[i])
617 			continue;
618 
619 		lpages = 1 + (base_gfn + npages - 1) /
620 			     KVM_PAGES_PER_HPAGE(level);
621 		lpages -= base_gfn / KVM_PAGES_PER_HPAGE(level);
622 
623 		new.lpage_info[i] = vmalloc(lpages * sizeof(*new.lpage_info[i]));
624 
625 		if (!new.lpage_info[i])
626 			goto out_free;
627 
628 		memset(new.lpage_info[i], 0,
629 		       lpages * sizeof(*new.lpage_info[i]));
630 
631 		if (base_gfn % KVM_PAGES_PER_HPAGE(level))
632 			new.lpage_info[i][0].write_count = 1;
633 		if ((base_gfn+npages) % KVM_PAGES_PER_HPAGE(level))
634 			new.lpage_info[i][lpages - 1].write_count = 1;
635 		ugfn = new.userspace_addr >> PAGE_SHIFT;
636 		/*
637 		 * If the gfn and userspace address are not aligned wrt each
638 		 * other, or if explicitly asked to, disable large page
639 		 * support for this slot
640 		 */
641 		if ((base_gfn ^ ugfn) & (KVM_PAGES_PER_HPAGE(level) - 1) ||
642 		    !largepages_enabled)
643 			for (j = 0; j < lpages; ++j)
644 				new.lpage_info[i][j].write_count = 1;
645 	}
646 
647 skip_lpage:
648 
649 	/* Allocate page dirty bitmap if needed */
650 	if ((new.flags & KVM_MEM_LOG_DIRTY_PAGES) && !new.dirty_bitmap) {
651 		unsigned dirty_bytes = ALIGN(npages, BITS_PER_LONG) / 8;
652 
653 		new.dirty_bitmap = vmalloc(dirty_bytes);
654 		if (!new.dirty_bitmap)
655 			goto out_free;
656 		memset(new.dirty_bitmap, 0, dirty_bytes);
657 		/* destroy any largepage mappings for dirty tracking */
658 		if (old.npages)
659 			flush_shadow = 1;
660 	}
661 #else  /* not defined CONFIG_S390 */
662 	new.user_alloc = user_alloc;
663 	if (user_alloc)
664 		new.userspace_addr = mem->userspace_addr;
665 #endif /* not defined CONFIG_S390 */
666 
667 	if (!npages) {
668 		r = -ENOMEM;
669 		slots = kzalloc(sizeof(struct kvm_memslots), GFP_KERNEL);
670 		if (!slots)
671 			goto out_free;
672 		memcpy(slots, kvm->memslots, sizeof(struct kvm_memslots));
673 		if (mem->slot >= slots->nmemslots)
674 			slots->nmemslots = mem->slot + 1;
675 		slots->memslots[mem->slot].flags |= KVM_MEMSLOT_INVALID;
676 
677 		old_memslots = kvm->memslots;
678 		rcu_assign_pointer(kvm->memslots, slots);
679 		synchronize_srcu_expedited(&kvm->srcu);
680 		/* From this point no new shadow pages pointing to a deleted
681 		 * memslot will be created.
682 		 *
683 		 * validation of sp->gfn happens in:
684 		 * 	- gfn_to_hva (kvm_read_guest, gfn_to_pfn)
685 		 * 	- kvm_is_visible_gfn (mmu_check_roots)
686 		 */
687 		kvm_arch_flush_shadow(kvm);
688 		kfree(old_memslots);
689 	}
690 
691 	r = kvm_arch_prepare_memory_region(kvm, &new, old, mem, user_alloc);
692 	if (r)
693 		goto out_free;
694 
695 #ifdef CONFIG_DMAR
696 	/* map the pages in iommu page table */
697 	if (npages) {
698 		r = kvm_iommu_map_pages(kvm, &new);
699 		if (r)
700 			goto out_free;
701 	}
702 #endif
703 
704 	r = -ENOMEM;
705 	slots = kzalloc(sizeof(struct kvm_memslots), GFP_KERNEL);
706 	if (!slots)
707 		goto out_free;
708 	memcpy(slots, kvm->memslots, sizeof(struct kvm_memslots));
709 	if (mem->slot >= slots->nmemslots)
710 		slots->nmemslots = mem->slot + 1;
711 
712 	/* actual memory is freed via old in kvm_free_physmem_slot below */
713 	if (!npages) {
714 		new.rmap = NULL;
715 		new.dirty_bitmap = NULL;
716 		for (i = 0; i < KVM_NR_PAGE_SIZES - 1; ++i)
717 			new.lpage_info[i] = NULL;
718 	}
719 
720 	slots->memslots[mem->slot] = new;
721 	old_memslots = kvm->memslots;
722 	rcu_assign_pointer(kvm->memslots, slots);
723 	synchronize_srcu_expedited(&kvm->srcu);
724 
725 	kvm_arch_commit_memory_region(kvm, mem, old, user_alloc);
726 
727 	kvm_free_physmem_slot(&old, &new);
728 	kfree(old_memslots);
729 
730 	if (flush_shadow)
731 		kvm_arch_flush_shadow(kvm);
732 
733 	return 0;
734 
735 out_free:
736 	kvm_free_physmem_slot(&new, &old);
737 out:
738 	return r;
739 
740 }
741 EXPORT_SYMBOL_GPL(__kvm_set_memory_region);
742 
743 int kvm_set_memory_region(struct kvm *kvm,
744 			  struct kvm_userspace_memory_region *mem,
745 			  int user_alloc)
746 {
747 	int r;
748 
749 	mutex_lock(&kvm->slots_lock);
750 	r = __kvm_set_memory_region(kvm, mem, user_alloc);
751 	mutex_unlock(&kvm->slots_lock);
752 	return r;
753 }
754 EXPORT_SYMBOL_GPL(kvm_set_memory_region);
755 
756 int kvm_vm_ioctl_set_memory_region(struct kvm *kvm,
757 				   struct
758 				   kvm_userspace_memory_region *mem,
759 				   int user_alloc)
760 {
761 	if (mem->slot >= KVM_MEMORY_SLOTS)
762 		return -EINVAL;
763 	return kvm_set_memory_region(kvm, mem, user_alloc);
764 }
765 
766 int kvm_get_dirty_log(struct kvm *kvm,
767 			struct kvm_dirty_log *log, int *is_dirty)
768 {
769 	struct kvm_memory_slot *memslot;
770 	int r, i;
771 	int n;
772 	unsigned long any = 0;
773 
774 	r = -EINVAL;
775 	if (log->slot >= KVM_MEMORY_SLOTS)
776 		goto out;
777 
778 	memslot = &kvm->memslots->memslots[log->slot];
779 	r = -ENOENT;
780 	if (!memslot->dirty_bitmap)
781 		goto out;
782 
783 	n = ALIGN(memslot->npages, BITS_PER_LONG) / 8;
784 
785 	for (i = 0; !any && i < n/sizeof(long); ++i)
786 		any = memslot->dirty_bitmap[i];
787 
788 	r = -EFAULT;
789 	if (copy_to_user(log->dirty_bitmap, memslot->dirty_bitmap, n))
790 		goto out;
791 
792 	if (any)
793 		*is_dirty = 1;
794 
795 	r = 0;
796 out:
797 	return r;
798 }
799 
800 void kvm_disable_largepages(void)
801 {
802 	largepages_enabled = false;
803 }
804 EXPORT_SYMBOL_GPL(kvm_disable_largepages);
805 
806 int is_error_page(struct page *page)
807 {
808 	return page == bad_page;
809 }
810 EXPORT_SYMBOL_GPL(is_error_page);
811 
812 int is_error_pfn(pfn_t pfn)
813 {
814 	return pfn == bad_pfn;
815 }
816 EXPORT_SYMBOL_GPL(is_error_pfn);
817 
818 static inline unsigned long bad_hva(void)
819 {
820 	return PAGE_OFFSET;
821 }
822 
823 int kvm_is_error_hva(unsigned long addr)
824 {
825 	return addr == bad_hva();
826 }
827 EXPORT_SYMBOL_GPL(kvm_is_error_hva);
828 
829 struct kvm_memory_slot *gfn_to_memslot_unaliased(struct kvm *kvm, gfn_t gfn)
830 {
831 	int i;
832 	struct kvm_memslots *slots = rcu_dereference(kvm->memslots);
833 
834 	for (i = 0; i < slots->nmemslots; ++i) {
835 		struct kvm_memory_slot *memslot = &slots->memslots[i];
836 
837 		if (gfn >= memslot->base_gfn
838 		    && gfn < memslot->base_gfn + memslot->npages)
839 			return memslot;
840 	}
841 	return NULL;
842 }
843 EXPORT_SYMBOL_GPL(gfn_to_memslot_unaliased);
844 
845 struct kvm_memory_slot *gfn_to_memslot(struct kvm *kvm, gfn_t gfn)
846 {
847 	gfn = unalias_gfn(kvm, gfn);
848 	return gfn_to_memslot_unaliased(kvm, gfn);
849 }
850 
851 int kvm_is_visible_gfn(struct kvm *kvm, gfn_t gfn)
852 {
853 	int i;
854 	struct kvm_memslots *slots = rcu_dereference(kvm->memslots);
855 
856 	gfn = unalias_gfn_instantiation(kvm, gfn);
857 	for (i = 0; i < KVM_MEMORY_SLOTS; ++i) {
858 		struct kvm_memory_slot *memslot = &slots->memslots[i];
859 
860 		if (memslot->flags & KVM_MEMSLOT_INVALID)
861 			continue;
862 
863 		if (gfn >= memslot->base_gfn
864 		    && gfn < memslot->base_gfn + memslot->npages)
865 			return 1;
866 	}
867 	return 0;
868 }
869 EXPORT_SYMBOL_GPL(kvm_is_visible_gfn);
870 
871 unsigned long kvm_host_page_size(struct kvm *kvm, gfn_t gfn)
872 {
873 	struct vm_area_struct *vma;
874 	unsigned long addr, size;
875 
876 	size = PAGE_SIZE;
877 
878 	addr = gfn_to_hva(kvm, gfn);
879 	if (kvm_is_error_hva(addr))
880 		return PAGE_SIZE;
881 
882 	down_read(&current->mm->mmap_sem);
883 	vma = find_vma(current->mm, addr);
884 	if (!vma)
885 		goto out;
886 
887 	size = vma_kernel_pagesize(vma);
888 
889 out:
890 	up_read(&current->mm->mmap_sem);
891 
892 	return size;
893 }
894 
895 int memslot_id(struct kvm *kvm, gfn_t gfn)
896 {
897 	int i;
898 	struct kvm_memslots *slots = rcu_dereference(kvm->memslots);
899 	struct kvm_memory_slot *memslot = NULL;
900 
901 	gfn = unalias_gfn(kvm, gfn);
902 	for (i = 0; i < slots->nmemslots; ++i) {
903 		memslot = &slots->memslots[i];
904 
905 		if (gfn >= memslot->base_gfn
906 		    && gfn < memslot->base_gfn + memslot->npages)
907 			break;
908 	}
909 
910 	return memslot - slots->memslots;
911 }
912 
913 unsigned long gfn_to_hva(struct kvm *kvm, gfn_t gfn)
914 {
915 	struct kvm_memory_slot *slot;
916 
917 	gfn = unalias_gfn_instantiation(kvm, gfn);
918 	slot = gfn_to_memslot_unaliased(kvm, gfn);
919 	if (!slot || slot->flags & KVM_MEMSLOT_INVALID)
920 		return bad_hva();
921 	return (slot->userspace_addr + (gfn - slot->base_gfn) * PAGE_SIZE);
922 }
923 EXPORT_SYMBOL_GPL(gfn_to_hva);
924 
925 static pfn_t hva_to_pfn(struct kvm *kvm, unsigned long addr)
926 {
927 	struct page *page[1];
928 	int npages;
929 	pfn_t pfn;
930 
931 	might_sleep();
932 
933 	npages = get_user_pages_fast(addr, 1, 1, page);
934 
935 	if (unlikely(npages != 1)) {
936 		struct vm_area_struct *vma;
937 
938 		down_read(&current->mm->mmap_sem);
939 		vma = find_vma(current->mm, addr);
940 
941 		if (vma == NULL || addr < vma->vm_start ||
942 		    !(vma->vm_flags & VM_PFNMAP)) {
943 			up_read(&current->mm->mmap_sem);
944 			get_page(bad_page);
945 			return page_to_pfn(bad_page);
946 		}
947 
948 		pfn = ((addr - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff;
949 		up_read(&current->mm->mmap_sem);
950 		BUG_ON(!kvm_is_mmio_pfn(pfn));
951 	} else
952 		pfn = page_to_pfn(page[0]);
953 
954 	return pfn;
955 }
956 
957 pfn_t gfn_to_pfn(struct kvm *kvm, gfn_t gfn)
958 {
959 	unsigned long addr;
960 
961 	addr = gfn_to_hva(kvm, gfn);
962 	if (kvm_is_error_hva(addr)) {
963 		get_page(bad_page);
964 		return page_to_pfn(bad_page);
965 	}
966 
967 	return hva_to_pfn(kvm, addr);
968 }
969 EXPORT_SYMBOL_GPL(gfn_to_pfn);
970 
971 static unsigned long gfn_to_hva_memslot(struct kvm_memory_slot *slot, gfn_t gfn)
972 {
973 	return (slot->userspace_addr + (gfn - slot->base_gfn) * PAGE_SIZE);
974 }
975 
976 pfn_t gfn_to_pfn_memslot(struct kvm *kvm,
977 			 struct kvm_memory_slot *slot, gfn_t gfn)
978 {
979 	unsigned long addr = gfn_to_hva_memslot(slot, gfn);
980 	return hva_to_pfn(kvm, addr);
981 }
982 
983 struct page *gfn_to_page(struct kvm *kvm, gfn_t gfn)
984 {
985 	pfn_t pfn;
986 
987 	pfn = gfn_to_pfn(kvm, gfn);
988 	if (!kvm_is_mmio_pfn(pfn))
989 		return pfn_to_page(pfn);
990 
991 	WARN_ON(kvm_is_mmio_pfn(pfn));
992 
993 	get_page(bad_page);
994 	return bad_page;
995 }
996 
997 EXPORT_SYMBOL_GPL(gfn_to_page);
998 
999 void kvm_release_page_clean(struct page *page)
1000 {
1001 	kvm_release_pfn_clean(page_to_pfn(page));
1002 }
1003 EXPORT_SYMBOL_GPL(kvm_release_page_clean);
1004 
1005 void kvm_release_pfn_clean(pfn_t pfn)
1006 {
1007 	if (!kvm_is_mmio_pfn(pfn))
1008 		put_page(pfn_to_page(pfn));
1009 }
1010 EXPORT_SYMBOL_GPL(kvm_release_pfn_clean);
1011 
1012 void kvm_release_page_dirty(struct page *page)
1013 {
1014 	kvm_release_pfn_dirty(page_to_pfn(page));
1015 }
1016 EXPORT_SYMBOL_GPL(kvm_release_page_dirty);
1017 
1018 void kvm_release_pfn_dirty(pfn_t pfn)
1019 {
1020 	kvm_set_pfn_dirty(pfn);
1021 	kvm_release_pfn_clean(pfn);
1022 }
1023 EXPORT_SYMBOL_GPL(kvm_release_pfn_dirty);
1024 
1025 void kvm_set_page_dirty(struct page *page)
1026 {
1027 	kvm_set_pfn_dirty(page_to_pfn(page));
1028 }
1029 EXPORT_SYMBOL_GPL(kvm_set_page_dirty);
1030 
1031 void kvm_set_pfn_dirty(pfn_t pfn)
1032 {
1033 	if (!kvm_is_mmio_pfn(pfn)) {
1034 		struct page *page = pfn_to_page(pfn);
1035 		if (!PageReserved(page))
1036 			SetPageDirty(page);
1037 	}
1038 }
1039 EXPORT_SYMBOL_GPL(kvm_set_pfn_dirty);
1040 
1041 void kvm_set_pfn_accessed(pfn_t pfn)
1042 {
1043 	if (!kvm_is_mmio_pfn(pfn))
1044 		mark_page_accessed(pfn_to_page(pfn));
1045 }
1046 EXPORT_SYMBOL_GPL(kvm_set_pfn_accessed);
1047 
1048 void kvm_get_pfn(pfn_t pfn)
1049 {
1050 	if (!kvm_is_mmio_pfn(pfn))
1051 		get_page(pfn_to_page(pfn));
1052 }
1053 EXPORT_SYMBOL_GPL(kvm_get_pfn);
1054 
1055 static int next_segment(unsigned long len, int offset)
1056 {
1057 	if (len > PAGE_SIZE - offset)
1058 		return PAGE_SIZE - offset;
1059 	else
1060 		return len;
1061 }
1062 
1063 int kvm_read_guest_page(struct kvm *kvm, gfn_t gfn, void *data, int offset,
1064 			int len)
1065 {
1066 	int r;
1067 	unsigned long addr;
1068 
1069 	addr = gfn_to_hva(kvm, gfn);
1070 	if (kvm_is_error_hva(addr))
1071 		return -EFAULT;
1072 	r = copy_from_user(data, (void __user *)addr + offset, len);
1073 	if (r)
1074 		return -EFAULT;
1075 	return 0;
1076 }
1077 EXPORT_SYMBOL_GPL(kvm_read_guest_page);
1078 
1079 int kvm_read_guest(struct kvm *kvm, gpa_t gpa, void *data, unsigned long len)
1080 {
1081 	gfn_t gfn = gpa >> PAGE_SHIFT;
1082 	int seg;
1083 	int offset = offset_in_page(gpa);
1084 	int ret;
1085 
1086 	while ((seg = next_segment(len, offset)) != 0) {
1087 		ret = kvm_read_guest_page(kvm, gfn, data, offset, seg);
1088 		if (ret < 0)
1089 			return ret;
1090 		offset = 0;
1091 		len -= seg;
1092 		data += seg;
1093 		++gfn;
1094 	}
1095 	return 0;
1096 }
1097 EXPORT_SYMBOL_GPL(kvm_read_guest);
1098 
1099 int kvm_read_guest_atomic(struct kvm *kvm, gpa_t gpa, void *data,
1100 			  unsigned long len)
1101 {
1102 	int r;
1103 	unsigned long addr;
1104 	gfn_t gfn = gpa >> PAGE_SHIFT;
1105 	int offset = offset_in_page(gpa);
1106 
1107 	addr = gfn_to_hva(kvm, gfn);
1108 	if (kvm_is_error_hva(addr))
1109 		return -EFAULT;
1110 	pagefault_disable();
1111 	r = __copy_from_user_inatomic(data, (void __user *)addr + offset, len);
1112 	pagefault_enable();
1113 	if (r)
1114 		return -EFAULT;
1115 	return 0;
1116 }
1117 EXPORT_SYMBOL(kvm_read_guest_atomic);
1118 
1119 int kvm_write_guest_page(struct kvm *kvm, gfn_t gfn, const void *data,
1120 			 int offset, int len)
1121 {
1122 	int r;
1123 	unsigned long addr;
1124 
1125 	addr = gfn_to_hva(kvm, gfn);
1126 	if (kvm_is_error_hva(addr))
1127 		return -EFAULT;
1128 	r = copy_to_user((void __user *)addr + offset, data, len);
1129 	if (r)
1130 		return -EFAULT;
1131 	mark_page_dirty(kvm, gfn);
1132 	return 0;
1133 }
1134 EXPORT_SYMBOL_GPL(kvm_write_guest_page);
1135 
1136 int kvm_write_guest(struct kvm *kvm, gpa_t gpa, const void *data,
1137 		    unsigned long len)
1138 {
1139 	gfn_t gfn = gpa >> PAGE_SHIFT;
1140 	int seg;
1141 	int offset = offset_in_page(gpa);
1142 	int ret;
1143 
1144 	while ((seg = next_segment(len, offset)) != 0) {
1145 		ret = kvm_write_guest_page(kvm, gfn, data, offset, seg);
1146 		if (ret < 0)
1147 			return ret;
1148 		offset = 0;
1149 		len -= seg;
1150 		data += seg;
1151 		++gfn;
1152 	}
1153 	return 0;
1154 }
1155 
1156 int kvm_clear_guest_page(struct kvm *kvm, gfn_t gfn, int offset, int len)
1157 {
1158 	return kvm_write_guest_page(kvm, gfn, empty_zero_page, offset, len);
1159 }
1160 EXPORT_SYMBOL_GPL(kvm_clear_guest_page);
1161 
1162 int kvm_clear_guest(struct kvm *kvm, gpa_t gpa, unsigned long len)
1163 {
1164 	gfn_t gfn = gpa >> PAGE_SHIFT;
1165 	int seg;
1166 	int offset = offset_in_page(gpa);
1167 	int ret;
1168 
1169         while ((seg = next_segment(len, offset)) != 0) {
1170 		ret = kvm_clear_guest_page(kvm, gfn, offset, seg);
1171 		if (ret < 0)
1172 			return ret;
1173 		offset = 0;
1174 		len -= seg;
1175 		++gfn;
1176 	}
1177 	return 0;
1178 }
1179 EXPORT_SYMBOL_GPL(kvm_clear_guest);
1180 
1181 void mark_page_dirty(struct kvm *kvm, gfn_t gfn)
1182 {
1183 	struct kvm_memory_slot *memslot;
1184 
1185 	gfn = unalias_gfn(kvm, gfn);
1186 	memslot = gfn_to_memslot_unaliased(kvm, gfn);
1187 	if (memslot && memslot->dirty_bitmap) {
1188 		unsigned long rel_gfn = gfn - memslot->base_gfn;
1189 
1190 		/* avoid RMW */
1191 		if (!generic_test_le_bit(rel_gfn, memslot->dirty_bitmap))
1192 			generic___set_le_bit(rel_gfn, memslot->dirty_bitmap);
1193 	}
1194 }
1195 
1196 /*
1197  * The vCPU has executed a HLT instruction with in-kernel mode enabled.
1198  */
1199 void kvm_vcpu_block(struct kvm_vcpu *vcpu)
1200 {
1201 	DEFINE_WAIT(wait);
1202 
1203 	for (;;) {
1204 		prepare_to_wait(&vcpu->wq, &wait, TASK_INTERRUPTIBLE);
1205 
1206 		if (kvm_arch_vcpu_runnable(vcpu)) {
1207 			set_bit(KVM_REQ_UNHALT, &vcpu->requests);
1208 			break;
1209 		}
1210 		if (kvm_cpu_has_pending_timer(vcpu))
1211 			break;
1212 		if (signal_pending(current))
1213 			break;
1214 
1215 		schedule();
1216 	}
1217 
1218 	finish_wait(&vcpu->wq, &wait);
1219 }
1220 
1221 void kvm_resched(struct kvm_vcpu *vcpu)
1222 {
1223 	if (!need_resched())
1224 		return;
1225 	cond_resched();
1226 }
1227 EXPORT_SYMBOL_GPL(kvm_resched);
1228 
1229 void kvm_vcpu_on_spin(struct kvm_vcpu *vcpu)
1230 {
1231 	ktime_t expires;
1232 	DEFINE_WAIT(wait);
1233 
1234 	prepare_to_wait(&vcpu->wq, &wait, TASK_INTERRUPTIBLE);
1235 
1236 	/* Sleep for 100 us, and hope lock-holder got scheduled */
1237 	expires = ktime_add_ns(ktime_get(), 100000UL);
1238 	schedule_hrtimeout(&expires, HRTIMER_MODE_ABS);
1239 
1240 	finish_wait(&vcpu->wq, &wait);
1241 }
1242 EXPORT_SYMBOL_GPL(kvm_vcpu_on_spin);
1243 
1244 static int kvm_vcpu_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
1245 {
1246 	struct kvm_vcpu *vcpu = vma->vm_file->private_data;
1247 	struct page *page;
1248 
1249 	if (vmf->pgoff == 0)
1250 		page = virt_to_page(vcpu->run);
1251 #ifdef CONFIG_X86
1252 	else if (vmf->pgoff == KVM_PIO_PAGE_OFFSET)
1253 		page = virt_to_page(vcpu->arch.pio_data);
1254 #endif
1255 #ifdef KVM_COALESCED_MMIO_PAGE_OFFSET
1256 	else if (vmf->pgoff == KVM_COALESCED_MMIO_PAGE_OFFSET)
1257 		page = virt_to_page(vcpu->kvm->coalesced_mmio_ring);
1258 #endif
1259 	else
1260 		return VM_FAULT_SIGBUS;
1261 	get_page(page);
1262 	vmf->page = page;
1263 	return 0;
1264 }
1265 
1266 static const struct vm_operations_struct kvm_vcpu_vm_ops = {
1267 	.fault = kvm_vcpu_fault,
1268 };
1269 
1270 static int kvm_vcpu_mmap(struct file *file, struct vm_area_struct *vma)
1271 {
1272 	vma->vm_ops = &kvm_vcpu_vm_ops;
1273 	return 0;
1274 }
1275 
1276 static int kvm_vcpu_release(struct inode *inode, struct file *filp)
1277 {
1278 	struct kvm_vcpu *vcpu = filp->private_data;
1279 
1280 	kvm_put_kvm(vcpu->kvm);
1281 	return 0;
1282 }
1283 
1284 static struct file_operations kvm_vcpu_fops = {
1285 	.release        = kvm_vcpu_release,
1286 	.unlocked_ioctl = kvm_vcpu_ioctl,
1287 	.compat_ioctl   = kvm_vcpu_ioctl,
1288 	.mmap           = kvm_vcpu_mmap,
1289 };
1290 
1291 /*
1292  * Allocates an inode for the vcpu.
1293  */
1294 static int create_vcpu_fd(struct kvm_vcpu *vcpu)
1295 {
1296 	return anon_inode_getfd("kvm-vcpu", &kvm_vcpu_fops, vcpu, O_RDWR);
1297 }
1298 
1299 /*
1300  * Creates some virtual cpus.  Good luck creating more than one.
1301  */
1302 static int kvm_vm_ioctl_create_vcpu(struct kvm *kvm, u32 id)
1303 {
1304 	int r;
1305 	struct kvm_vcpu *vcpu, *v;
1306 
1307 	vcpu = kvm_arch_vcpu_create(kvm, id);
1308 	if (IS_ERR(vcpu))
1309 		return PTR_ERR(vcpu);
1310 
1311 	preempt_notifier_init(&vcpu->preempt_notifier, &kvm_preempt_ops);
1312 
1313 	r = kvm_arch_vcpu_setup(vcpu);
1314 	if (r)
1315 		return r;
1316 
1317 	mutex_lock(&kvm->lock);
1318 	if (atomic_read(&kvm->online_vcpus) == KVM_MAX_VCPUS) {
1319 		r = -EINVAL;
1320 		goto vcpu_destroy;
1321 	}
1322 
1323 	kvm_for_each_vcpu(r, v, kvm)
1324 		if (v->vcpu_id == id) {
1325 			r = -EEXIST;
1326 			goto vcpu_destroy;
1327 		}
1328 
1329 	BUG_ON(kvm->vcpus[atomic_read(&kvm->online_vcpus)]);
1330 
1331 	/* Now it's all set up, let userspace reach it */
1332 	kvm_get_kvm(kvm);
1333 	r = create_vcpu_fd(vcpu);
1334 	if (r < 0) {
1335 		kvm_put_kvm(kvm);
1336 		goto vcpu_destroy;
1337 	}
1338 
1339 	kvm->vcpus[atomic_read(&kvm->online_vcpus)] = vcpu;
1340 	smp_wmb();
1341 	atomic_inc(&kvm->online_vcpus);
1342 
1343 #ifdef CONFIG_KVM_APIC_ARCHITECTURE
1344 	if (kvm->bsp_vcpu_id == id)
1345 		kvm->bsp_vcpu = vcpu;
1346 #endif
1347 	mutex_unlock(&kvm->lock);
1348 	return r;
1349 
1350 vcpu_destroy:
1351 	mutex_unlock(&kvm->lock);
1352 	kvm_arch_vcpu_destroy(vcpu);
1353 	return r;
1354 }
1355 
1356 static int kvm_vcpu_ioctl_set_sigmask(struct kvm_vcpu *vcpu, sigset_t *sigset)
1357 {
1358 	if (sigset) {
1359 		sigdelsetmask(sigset, sigmask(SIGKILL)|sigmask(SIGSTOP));
1360 		vcpu->sigset_active = 1;
1361 		vcpu->sigset = *sigset;
1362 	} else
1363 		vcpu->sigset_active = 0;
1364 	return 0;
1365 }
1366 
1367 static long kvm_vcpu_ioctl(struct file *filp,
1368 			   unsigned int ioctl, unsigned long arg)
1369 {
1370 	struct kvm_vcpu *vcpu = filp->private_data;
1371 	void __user *argp = (void __user *)arg;
1372 	int r;
1373 	struct kvm_fpu *fpu = NULL;
1374 	struct kvm_sregs *kvm_sregs = NULL;
1375 
1376 	if (vcpu->kvm->mm != current->mm)
1377 		return -EIO;
1378 	switch (ioctl) {
1379 	case KVM_RUN:
1380 		r = -EINVAL;
1381 		if (arg)
1382 			goto out;
1383 		r = kvm_arch_vcpu_ioctl_run(vcpu, vcpu->run);
1384 		break;
1385 	case KVM_GET_REGS: {
1386 		struct kvm_regs *kvm_regs;
1387 
1388 		r = -ENOMEM;
1389 		kvm_regs = kzalloc(sizeof(struct kvm_regs), GFP_KERNEL);
1390 		if (!kvm_regs)
1391 			goto out;
1392 		r = kvm_arch_vcpu_ioctl_get_regs(vcpu, kvm_regs);
1393 		if (r)
1394 			goto out_free1;
1395 		r = -EFAULT;
1396 		if (copy_to_user(argp, kvm_regs, sizeof(struct kvm_regs)))
1397 			goto out_free1;
1398 		r = 0;
1399 out_free1:
1400 		kfree(kvm_regs);
1401 		break;
1402 	}
1403 	case KVM_SET_REGS: {
1404 		struct kvm_regs *kvm_regs;
1405 
1406 		r = -ENOMEM;
1407 		kvm_regs = kzalloc(sizeof(struct kvm_regs), GFP_KERNEL);
1408 		if (!kvm_regs)
1409 			goto out;
1410 		r = -EFAULT;
1411 		if (copy_from_user(kvm_regs, argp, sizeof(struct kvm_regs)))
1412 			goto out_free2;
1413 		r = kvm_arch_vcpu_ioctl_set_regs(vcpu, kvm_regs);
1414 		if (r)
1415 			goto out_free2;
1416 		r = 0;
1417 out_free2:
1418 		kfree(kvm_regs);
1419 		break;
1420 	}
1421 	case KVM_GET_SREGS: {
1422 		kvm_sregs = kzalloc(sizeof(struct kvm_sregs), GFP_KERNEL);
1423 		r = -ENOMEM;
1424 		if (!kvm_sregs)
1425 			goto out;
1426 		r = kvm_arch_vcpu_ioctl_get_sregs(vcpu, kvm_sregs);
1427 		if (r)
1428 			goto out;
1429 		r = -EFAULT;
1430 		if (copy_to_user(argp, kvm_sregs, sizeof(struct kvm_sregs)))
1431 			goto out;
1432 		r = 0;
1433 		break;
1434 	}
1435 	case KVM_SET_SREGS: {
1436 		kvm_sregs = kmalloc(sizeof(struct kvm_sregs), GFP_KERNEL);
1437 		r = -ENOMEM;
1438 		if (!kvm_sregs)
1439 			goto out;
1440 		r = -EFAULT;
1441 		if (copy_from_user(kvm_sregs, argp, sizeof(struct kvm_sregs)))
1442 			goto out;
1443 		r = kvm_arch_vcpu_ioctl_set_sregs(vcpu, kvm_sregs);
1444 		if (r)
1445 			goto out;
1446 		r = 0;
1447 		break;
1448 	}
1449 	case KVM_GET_MP_STATE: {
1450 		struct kvm_mp_state mp_state;
1451 
1452 		r = kvm_arch_vcpu_ioctl_get_mpstate(vcpu, &mp_state);
1453 		if (r)
1454 			goto out;
1455 		r = -EFAULT;
1456 		if (copy_to_user(argp, &mp_state, sizeof mp_state))
1457 			goto out;
1458 		r = 0;
1459 		break;
1460 	}
1461 	case KVM_SET_MP_STATE: {
1462 		struct kvm_mp_state mp_state;
1463 
1464 		r = -EFAULT;
1465 		if (copy_from_user(&mp_state, argp, sizeof mp_state))
1466 			goto out;
1467 		r = kvm_arch_vcpu_ioctl_set_mpstate(vcpu, &mp_state);
1468 		if (r)
1469 			goto out;
1470 		r = 0;
1471 		break;
1472 	}
1473 	case KVM_TRANSLATE: {
1474 		struct kvm_translation tr;
1475 
1476 		r = -EFAULT;
1477 		if (copy_from_user(&tr, argp, sizeof tr))
1478 			goto out;
1479 		r = kvm_arch_vcpu_ioctl_translate(vcpu, &tr);
1480 		if (r)
1481 			goto out;
1482 		r = -EFAULT;
1483 		if (copy_to_user(argp, &tr, sizeof tr))
1484 			goto out;
1485 		r = 0;
1486 		break;
1487 	}
1488 	case KVM_SET_GUEST_DEBUG: {
1489 		struct kvm_guest_debug dbg;
1490 
1491 		r = -EFAULT;
1492 		if (copy_from_user(&dbg, argp, sizeof dbg))
1493 			goto out;
1494 		r = kvm_arch_vcpu_ioctl_set_guest_debug(vcpu, &dbg);
1495 		if (r)
1496 			goto out;
1497 		r = 0;
1498 		break;
1499 	}
1500 	case KVM_SET_SIGNAL_MASK: {
1501 		struct kvm_signal_mask __user *sigmask_arg = argp;
1502 		struct kvm_signal_mask kvm_sigmask;
1503 		sigset_t sigset, *p;
1504 
1505 		p = NULL;
1506 		if (argp) {
1507 			r = -EFAULT;
1508 			if (copy_from_user(&kvm_sigmask, argp,
1509 					   sizeof kvm_sigmask))
1510 				goto out;
1511 			r = -EINVAL;
1512 			if (kvm_sigmask.len != sizeof sigset)
1513 				goto out;
1514 			r = -EFAULT;
1515 			if (copy_from_user(&sigset, sigmask_arg->sigset,
1516 					   sizeof sigset))
1517 				goto out;
1518 			p = &sigset;
1519 		}
1520 		r = kvm_vcpu_ioctl_set_sigmask(vcpu, &sigset);
1521 		break;
1522 	}
1523 	case KVM_GET_FPU: {
1524 		fpu = kzalloc(sizeof(struct kvm_fpu), GFP_KERNEL);
1525 		r = -ENOMEM;
1526 		if (!fpu)
1527 			goto out;
1528 		r = kvm_arch_vcpu_ioctl_get_fpu(vcpu, fpu);
1529 		if (r)
1530 			goto out;
1531 		r = -EFAULT;
1532 		if (copy_to_user(argp, fpu, sizeof(struct kvm_fpu)))
1533 			goto out;
1534 		r = 0;
1535 		break;
1536 	}
1537 	case KVM_SET_FPU: {
1538 		fpu = kmalloc(sizeof(struct kvm_fpu), GFP_KERNEL);
1539 		r = -ENOMEM;
1540 		if (!fpu)
1541 			goto out;
1542 		r = -EFAULT;
1543 		if (copy_from_user(fpu, argp, sizeof(struct kvm_fpu)))
1544 			goto out;
1545 		r = kvm_arch_vcpu_ioctl_set_fpu(vcpu, fpu);
1546 		if (r)
1547 			goto out;
1548 		r = 0;
1549 		break;
1550 	}
1551 	default:
1552 		r = kvm_arch_vcpu_ioctl(filp, ioctl, arg);
1553 	}
1554 out:
1555 	kfree(fpu);
1556 	kfree(kvm_sregs);
1557 	return r;
1558 }
1559 
1560 static long kvm_vm_ioctl(struct file *filp,
1561 			   unsigned int ioctl, unsigned long arg)
1562 {
1563 	struct kvm *kvm = filp->private_data;
1564 	void __user *argp = (void __user *)arg;
1565 	int r;
1566 
1567 	if (kvm->mm != current->mm)
1568 		return -EIO;
1569 	switch (ioctl) {
1570 	case KVM_CREATE_VCPU:
1571 		r = kvm_vm_ioctl_create_vcpu(kvm, arg);
1572 		if (r < 0)
1573 			goto out;
1574 		break;
1575 	case KVM_SET_USER_MEMORY_REGION: {
1576 		struct kvm_userspace_memory_region kvm_userspace_mem;
1577 
1578 		r = -EFAULT;
1579 		if (copy_from_user(&kvm_userspace_mem, argp,
1580 						sizeof kvm_userspace_mem))
1581 			goto out;
1582 
1583 		r = kvm_vm_ioctl_set_memory_region(kvm, &kvm_userspace_mem, 1);
1584 		if (r)
1585 			goto out;
1586 		break;
1587 	}
1588 	case KVM_GET_DIRTY_LOG: {
1589 		struct kvm_dirty_log log;
1590 
1591 		r = -EFAULT;
1592 		if (copy_from_user(&log, argp, sizeof log))
1593 			goto out;
1594 		r = kvm_vm_ioctl_get_dirty_log(kvm, &log);
1595 		if (r)
1596 			goto out;
1597 		break;
1598 	}
1599 #ifdef KVM_COALESCED_MMIO_PAGE_OFFSET
1600 	case KVM_REGISTER_COALESCED_MMIO: {
1601 		struct kvm_coalesced_mmio_zone zone;
1602 		r = -EFAULT;
1603 		if (copy_from_user(&zone, argp, sizeof zone))
1604 			goto out;
1605 		r = -ENXIO;
1606 		r = kvm_vm_ioctl_register_coalesced_mmio(kvm, &zone);
1607 		if (r)
1608 			goto out;
1609 		r = 0;
1610 		break;
1611 	}
1612 	case KVM_UNREGISTER_COALESCED_MMIO: {
1613 		struct kvm_coalesced_mmio_zone zone;
1614 		r = -EFAULT;
1615 		if (copy_from_user(&zone, argp, sizeof zone))
1616 			goto out;
1617 		r = -ENXIO;
1618 		r = kvm_vm_ioctl_unregister_coalesced_mmio(kvm, &zone);
1619 		if (r)
1620 			goto out;
1621 		r = 0;
1622 		break;
1623 	}
1624 #endif
1625 	case KVM_IRQFD: {
1626 		struct kvm_irqfd data;
1627 
1628 		r = -EFAULT;
1629 		if (copy_from_user(&data, argp, sizeof data))
1630 			goto out;
1631 		r = kvm_irqfd(kvm, data.fd, data.gsi, data.flags);
1632 		break;
1633 	}
1634 	case KVM_IOEVENTFD: {
1635 		struct kvm_ioeventfd data;
1636 
1637 		r = -EFAULT;
1638 		if (copy_from_user(&data, argp, sizeof data))
1639 			goto out;
1640 		r = kvm_ioeventfd(kvm, &data);
1641 		break;
1642 	}
1643 #ifdef CONFIG_KVM_APIC_ARCHITECTURE
1644 	case KVM_SET_BOOT_CPU_ID:
1645 		r = 0;
1646 		mutex_lock(&kvm->lock);
1647 		if (atomic_read(&kvm->online_vcpus) != 0)
1648 			r = -EBUSY;
1649 		else
1650 			kvm->bsp_vcpu_id = arg;
1651 		mutex_unlock(&kvm->lock);
1652 		break;
1653 #endif
1654 	default:
1655 		r = kvm_arch_vm_ioctl(filp, ioctl, arg);
1656 		if (r == -ENOTTY)
1657 			r = kvm_vm_ioctl_assigned_device(kvm, ioctl, arg);
1658 	}
1659 out:
1660 	return r;
1661 }
1662 
1663 #ifdef CONFIG_COMPAT
1664 struct compat_kvm_dirty_log {
1665 	__u32 slot;
1666 	__u32 padding1;
1667 	union {
1668 		compat_uptr_t dirty_bitmap; /* one bit per page */
1669 		__u64 padding2;
1670 	};
1671 };
1672 
1673 static long kvm_vm_compat_ioctl(struct file *filp,
1674 			   unsigned int ioctl, unsigned long arg)
1675 {
1676 	struct kvm *kvm = filp->private_data;
1677 	int r;
1678 
1679 	if (kvm->mm != current->mm)
1680 		return -EIO;
1681 	switch (ioctl) {
1682 	case KVM_GET_DIRTY_LOG: {
1683 		struct compat_kvm_dirty_log compat_log;
1684 		struct kvm_dirty_log log;
1685 
1686 		r = -EFAULT;
1687 		if (copy_from_user(&compat_log, (void __user *)arg,
1688 				   sizeof(compat_log)))
1689 			goto out;
1690 		log.slot	 = compat_log.slot;
1691 		log.padding1	 = compat_log.padding1;
1692 		log.padding2	 = compat_log.padding2;
1693 		log.dirty_bitmap = compat_ptr(compat_log.dirty_bitmap);
1694 
1695 		r = kvm_vm_ioctl_get_dirty_log(kvm, &log);
1696 		if (r)
1697 			goto out;
1698 		break;
1699 	}
1700 	default:
1701 		r = kvm_vm_ioctl(filp, ioctl, arg);
1702 	}
1703 
1704 out:
1705 	return r;
1706 }
1707 #endif
1708 
1709 static int kvm_vm_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
1710 {
1711 	struct page *page[1];
1712 	unsigned long addr;
1713 	int npages;
1714 	gfn_t gfn = vmf->pgoff;
1715 	struct kvm *kvm = vma->vm_file->private_data;
1716 
1717 	addr = gfn_to_hva(kvm, gfn);
1718 	if (kvm_is_error_hva(addr))
1719 		return VM_FAULT_SIGBUS;
1720 
1721 	npages = get_user_pages(current, current->mm, addr, 1, 1, 0, page,
1722 				NULL);
1723 	if (unlikely(npages != 1))
1724 		return VM_FAULT_SIGBUS;
1725 
1726 	vmf->page = page[0];
1727 	return 0;
1728 }
1729 
1730 static const struct vm_operations_struct kvm_vm_vm_ops = {
1731 	.fault = kvm_vm_fault,
1732 };
1733 
1734 static int kvm_vm_mmap(struct file *file, struct vm_area_struct *vma)
1735 {
1736 	vma->vm_ops = &kvm_vm_vm_ops;
1737 	return 0;
1738 }
1739 
1740 static struct file_operations kvm_vm_fops = {
1741 	.release        = kvm_vm_release,
1742 	.unlocked_ioctl = kvm_vm_ioctl,
1743 #ifdef CONFIG_COMPAT
1744 	.compat_ioctl   = kvm_vm_compat_ioctl,
1745 #endif
1746 	.mmap           = kvm_vm_mmap,
1747 };
1748 
1749 static int kvm_dev_ioctl_create_vm(void)
1750 {
1751 	int fd;
1752 	struct kvm *kvm;
1753 
1754 	kvm = kvm_create_vm();
1755 	if (IS_ERR(kvm))
1756 		return PTR_ERR(kvm);
1757 	fd = anon_inode_getfd("kvm-vm", &kvm_vm_fops, kvm, O_RDWR);
1758 	if (fd < 0)
1759 		kvm_put_kvm(kvm);
1760 
1761 	return fd;
1762 }
1763 
1764 static long kvm_dev_ioctl_check_extension_generic(long arg)
1765 {
1766 	switch (arg) {
1767 	case KVM_CAP_USER_MEMORY:
1768 	case KVM_CAP_DESTROY_MEMORY_REGION_WORKS:
1769 	case KVM_CAP_JOIN_MEMORY_REGIONS_WORKS:
1770 #ifdef CONFIG_KVM_APIC_ARCHITECTURE
1771 	case KVM_CAP_SET_BOOT_CPU_ID:
1772 #endif
1773 	case KVM_CAP_INTERNAL_ERROR_DATA:
1774 		return 1;
1775 #ifdef CONFIG_HAVE_KVM_IRQCHIP
1776 	case KVM_CAP_IRQ_ROUTING:
1777 		return KVM_MAX_IRQ_ROUTES;
1778 #endif
1779 	default:
1780 		break;
1781 	}
1782 	return kvm_dev_ioctl_check_extension(arg);
1783 }
1784 
1785 static long kvm_dev_ioctl(struct file *filp,
1786 			  unsigned int ioctl, unsigned long arg)
1787 {
1788 	long r = -EINVAL;
1789 
1790 	switch (ioctl) {
1791 	case KVM_GET_API_VERSION:
1792 		r = -EINVAL;
1793 		if (arg)
1794 			goto out;
1795 		r = KVM_API_VERSION;
1796 		break;
1797 	case KVM_CREATE_VM:
1798 		r = -EINVAL;
1799 		if (arg)
1800 			goto out;
1801 		r = kvm_dev_ioctl_create_vm();
1802 		break;
1803 	case KVM_CHECK_EXTENSION:
1804 		r = kvm_dev_ioctl_check_extension_generic(arg);
1805 		break;
1806 	case KVM_GET_VCPU_MMAP_SIZE:
1807 		r = -EINVAL;
1808 		if (arg)
1809 			goto out;
1810 		r = PAGE_SIZE;     /* struct kvm_run */
1811 #ifdef CONFIG_X86
1812 		r += PAGE_SIZE;    /* pio data page */
1813 #endif
1814 #ifdef KVM_COALESCED_MMIO_PAGE_OFFSET
1815 		r += PAGE_SIZE;    /* coalesced mmio ring page */
1816 #endif
1817 		break;
1818 	case KVM_TRACE_ENABLE:
1819 	case KVM_TRACE_PAUSE:
1820 	case KVM_TRACE_DISABLE:
1821 		r = -EOPNOTSUPP;
1822 		break;
1823 	default:
1824 		return kvm_arch_dev_ioctl(filp, ioctl, arg);
1825 	}
1826 out:
1827 	return r;
1828 }
1829 
1830 static struct file_operations kvm_chardev_ops = {
1831 	.unlocked_ioctl = kvm_dev_ioctl,
1832 	.compat_ioctl   = kvm_dev_ioctl,
1833 };
1834 
1835 static struct miscdevice kvm_dev = {
1836 	KVM_MINOR,
1837 	"kvm",
1838 	&kvm_chardev_ops,
1839 };
1840 
1841 static void hardware_enable(void *junk)
1842 {
1843 	int cpu = raw_smp_processor_id();
1844 	int r;
1845 
1846 	if (cpumask_test_cpu(cpu, cpus_hardware_enabled))
1847 		return;
1848 
1849 	cpumask_set_cpu(cpu, cpus_hardware_enabled);
1850 
1851 	r = kvm_arch_hardware_enable(NULL);
1852 
1853 	if (r) {
1854 		cpumask_clear_cpu(cpu, cpus_hardware_enabled);
1855 		atomic_inc(&hardware_enable_failed);
1856 		printk(KERN_INFO "kvm: enabling virtualization on "
1857 				 "CPU%d failed\n", cpu);
1858 	}
1859 }
1860 
1861 static void hardware_disable(void *junk)
1862 {
1863 	int cpu = raw_smp_processor_id();
1864 
1865 	if (!cpumask_test_cpu(cpu, cpus_hardware_enabled))
1866 		return;
1867 	cpumask_clear_cpu(cpu, cpus_hardware_enabled);
1868 	kvm_arch_hardware_disable(NULL);
1869 }
1870 
1871 static void hardware_disable_all_nolock(void)
1872 {
1873 	BUG_ON(!kvm_usage_count);
1874 
1875 	kvm_usage_count--;
1876 	if (!kvm_usage_count)
1877 		on_each_cpu(hardware_disable, NULL, 1);
1878 }
1879 
1880 static void hardware_disable_all(void)
1881 {
1882 	spin_lock(&kvm_lock);
1883 	hardware_disable_all_nolock();
1884 	spin_unlock(&kvm_lock);
1885 }
1886 
1887 static int hardware_enable_all(void)
1888 {
1889 	int r = 0;
1890 
1891 	spin_lock(&kvm_lock);
1892 
1893 	kvm_usage_count++;
1894 	if (kvm_usage_count == 1) {
1895 		atomic_set(&hardware_enable_failed, 0);
1896 		on_each_cpu(hardware_enable, NULL, 1);
1897 
1898 		if (atomic_read(&hardware_enable_failed)) {
1899 			hardware_disable_all_nolock();
1900 			r = -EBUSY;
1901 		}
1902 	}
1903 
1904 	spin_unlock(&kvm_lock);
1905 
1906 	return r;
1907 }
1908 
1909 static int kvm_cpu_hotplug(struct notifier_block *notifier, unsigned long val,
1910 			   void *v)
1911 {
1912 	int cpu = (long)v;
1913 
1914 	if (!kvm_usage_count)
1915 		return NOTIFY_OK;
1916 
1917 	val &= ~CPU_TASKS_FROZEN;
1918 	switch (val) {
1919 	case CPU_DYING:
1920 		printk(KERN_INFO "kvm: disabling virtualization on CPU%d\n",
1921 		       cpu);
1922 		hardware_disable(NULL);
1923 		break;
1924 	case CPU_UP_CANCELED:
1925 		printk(KERN_INFO "kvm: disabling virtualization on CPU%d\n",
1926 		       cpu);
1927 		smp_call_function_single(cpu, hardware_disable, NULL, 1);
1928 		break;
1929 	case CPU_ONLINE:
1930 		printk(KERN_INFO "kvm: enabling virtualization on CPU%d\n",
1931 		       cpu);
1932 		smp_call_function_single(cpu, hardware_enable, NULL, 1);
1933 		break;
1934 	}
1935 	return NOTIFY_OK;
1936 }
1937 
1938 
1939 asmlinkage void kvm_handle_fault_on_reboot(void)
1940 {
1941 	if (kvm_rebooting)
1942 		/* spin while reset goes on */
1943 		while (true)
1944 			;
1945 	/* Fault while not rebooting.  We want the trace. */
1946 	BUG();
1947 }
1948 EXPORT_SYMBOL_GPL(kvm_handle_fault_on_reboot);
1949 
1950 static int kvm_reboot(struct notifier_block *notifier, unsigned long val,
1951 		      void *v)
1952 {
1953 	/*
1954 	 * Some (well, at least mine) BIOSes hang on reboot if
1955 	 * in vmx root mode.
1956 	 *
1957 	 * And Intel TXT required VMX off for all cpu when system shutdown.
1958 	 */
1959 	printk(KERN_INFO "kvm: exiting hardware virtualization\n");
1960 	kvm_rebooting = true;
1961 	on_each_cpu(hardware_disable, NULL, 1);
1962 	return NOTIFY_OK;
1963 }
1964 
1965 static struct notifier_block kvm_reboot_notifier = {
1966 	.notifier_call = kvm_reboot,
1967 	.priority = 0,
1968 };
1969 
1970 static void kvm_io_bus_destroy(struct kvm_io_bus *bus)
1971 {
1972 	int i;
1973 
1974 	for (i = 0; i < bus->dev_count; i++) {
1975 		struct kvm_io_device *pos = bus->devs[i];
1976 
1977 		kvm_iodevice_destructor(pos);
1978 	}
1979 	kfree(bus);
1980 }
1981 
1982 /* kvm_io_bus_write - called under kvm->slots_lock */
1983 int kvm_io_bus_write(struct kvm *kvm, enum kvm_bus bus_idx, gpa_t addr,
1984 		     int len, const void *val)
1985 {
1986 	int i;
1987 	struct kvm_io_bus *bus = rcu_dereference(kvm->buses[bus_idx]);
1988 	for (i = 0; i < bus->dev_count; i++)
1989 		if (!kvm_iodevice_write(bus->devs[i], addr, len, val))
1990 			return 0;
1991 	return -EOPNOTSUPP;
1992 }
1993 
1994 /* kvm_io_bus_read - called under kvm->slots_lock */
1995 int kvm_io_bus_read(struct kvm *kvm, enum kvm_bus bus_idx, gpa_t addr,
1996 		    int len, void *val)
1997 {
1998 	int i;
1999 	struct kvm_io_bus *bus = rcu_dereference(kvm->buses[bus_idx]);
2000 
2001 	for (i = 0; i < bus->dev_count; i++)
2002 		if (!kvm_iodevice_read(bus->devs[i], addr, len, val))
2003 			return 0;
2004 	return -EOPNOTSUPP;
2005 }
2006 
2007 /* Caller must hold slots_lock. */
2008 int kvm_io_bus_register_dev(struct kvm *kvm, enum kvm_bus bus_idx,
2009 			    struct kvm_io_device *dev)
2010 {
2011 	struct kvm_io_bus *new_bus, *bus;
2012 
2013 	bus = kvm->buses[bus_idx];
2014 	if (bus->dev_count > NR_IOBUS_DEVS-1)
2015 		return -ENOSPC;
2016 
2017 	new_bus = kzalloc(sizeof(struct kvm_io_bus), GFP_KERNEL);
2018 	if (!new_bus)
2019 		return -ENOMEM;
2020 	memcpy(new_bus, bus, sizeof(struct kvm_io_bus));
2021 	new_bus->devs[new_bus->dev_count++] = dev;
2022 	rcu_assign_pointer(kvm->buses[bus_idx], new_bus);
2023 	synchronize_srcu_expedited(&kvm->srcu);
2024 	kfree(bus);
2025 
2026 	return 0;
2027 }
2028 
2029 /* Caller must hold slots_lock. */
2030 int kvm_io_bus_unregister_dev(struct kvm *kvm, enum kvm_bus bus_idx,
2031 			      struct kvm_io_device *dev)
2032 {
2033 	int i, r;
2034 	struct kvm_io_bus *new_bus, *bus;
2035 
2036 	new_bus = kzalloc(sizeof(struct kvm_io_bus), GFP_KERNEL);
2037 	if (!new_bus)
2038 		return -ENOMEM;
2039 
2040 	bus = kvm->buses[bus_idx];
2041 	memcpy(new_bus, bus, sizeof(struct kvm_io_bus));
2042 
2043 	r = -ENOENT;
2044 	for (i = 0; i < new_bus->dev_count; i++)
2045 		if (new_bus->devs[i] == dev) {
2046 			r = 0;
2047 			new_bus->devs[i] = new_bus->devs[--new_bus->dev_count];
2048 			break;
2049 		}
2050 
2051 	if (r) {
2052 		kfree(new_bus);
2053 		return r;
2054 	}
2055 
2056 	rcu_assign_pointer(kvm->buses[bus_idx], new_bus);
2057 	synchronize_srcu_expedited(&kvm->srcu);
2058 	kfree(bus);
2059 	return r;
2060 }
2061 
2062 static struct notifier_block kvm_cpu_notifier = {
2063 	.notifier_call = kvm_cpu_hotplug,
2064 	.priority = 20, /* must be > scheduler priority */
2065 };
2066 
2067 static int vm_stat_get(void *_offset, u64 *val)
2068 {
2069 	unsigned offset = (long)_offset;
2070 	struct kvm *kvm;
2071 
2072 	*val = 0;
2073 	spin_lock(&kvm_lock);
2074 	list_for_each_entry(kvm, &vm_list, vm_list)
2075 		*val += *(u32 *)((void *)kvm + offset);
2076 	spin_unlock(&kvm_lock);
2077 	return 0;
2078 }
2079 
2080 DEFINE_SIMPLE_ATTRIBUTE(vm_stat_fops, vm_stat_get, NULL, "%llu\n");
2081 
2082 static int vcpu_stat_get(void *_offset, u64 *val)
2083 {
2084 	unsigned offset = (long)_offset;
2085 	struct kvm *kvm;
2086 	struct kvm_vcpu *vcpu;
2087 	int i;
2088 
2089 	*val = 0;
2090 	spin_lock(&kvm_lock);
2091 	list_for_each_entry(kvm, &vm_list, vm_list)
2092 		kvm_for_each_vcpu(i, vcpu, kvm)
2093 			*val += *(u32 *)((void *)vcpu + offset);
2094 
2095 	spin_unlock(&kvm_lock);
2096 	return 0;
2097 }
2098 
2099 DEFINE_SIMPLE_ATTRIBUTE(vcpu_stat_fops, vcpu_stat_get, NULL, "%llu\n");
2100 
2101 static const struct file_operations *stat_fops[] = {
2102 	[KVM_STAT_VCPU] = &vcpu_stat_fops,
2103 	[KVM_STAT_VM]   = &vm_stat_fops,
2104 };
2105 
2106 static void kvm_init_debug(void)
2107 {
2108 	struct kvm_stats_debugfs_item *p;
2109 
2110 	kvm_debugfs_dir = debugfs_create_dir("kvm", NULL);
2111 	for (p = debugfs_entries; p->name; ++p)
2112 		p->dentry = debugfs_create_file(p->name, 0444, kvm_debugfs_dir,
2113 						(void *)(long)p->offset,
2114 						stat_fops[p->kind]);
2115 }
2116 
2117 static void kvm_exit_debug(void)
2118 {
2119 	struct kvm_stats_debugfs_item *p;
2120 
2121 	for (p = debugfs_entries; p->name; ++p)
2122 		debugfs_remove(p->dentry);
2123 	debugfs_remove(kvm_debugfs_dir);
2124 }
2125 
2126 static int kvm_suspend(struct sys_device *dev, pm_message_t state)
2127 {
2128 	if (kvm_usage_count)
2129 		hardware_disable(NULL);
2130 	return 0;
2131 }
2132 
2133 static int kvm_resume(struct sys_device *dev)
2134 {
2135 	if (kvm_usage_count)
2136 		hardware_enable(NULL);
2137 	return 0;
2138 }
2139 
2140 static struct sysdev_class kvm_sysdev_class = {
2141 	.name = "kvm",
2142 	.suspend = kvm_suspend,
2143 	.resume = kvm_resume,
2144 };
2145 
2146 static struct sys_device kvm_sysdev = {
2147 	.id = 0,
2148 	.cls = &kvm_sysdev_class,
2149 };
2150 
2151 struct page *bad_page;
2152 pfn_t bad_pfn;
2153 
2154 static inline
2155 struct kvm_vcpu *preempt_notifier_to_vcpu(struct preempt_notifier *pn)
2156 {
2157 	return container_of(pn, struct kvm_vcpu, preempt_notifier);
2158 }
2159 
2160 static void kvm_sched_in(struct preempt_notifier *pn, int cpu)
2161 {
2162 	struct kvm_vcpu *vcpu = preempt_notifier_to_vcpu(pn);
2163 
2164 	kvm_arch_vcpu_load(vcpu, cpu);
2165 }
2166 
2167 static void kvm_sched_out(struct preempt_notifier *pn,
2168 			  struct task_struct *next)
2169 {
2170 	struct kvm_vcpu *vcpu = preempt_notifier_to_vcpu(pn);
2171 
2172 	kvm_arch_vcpu_put(vcpu);
2173 }
2174 
2175 int kvm_init(void *opaque, unsigned int vcpu_size,
2176 		  struct module *module)
2177 {
2178 	int r;
2179 	int cpu;
2180 
2181 	r = kvm_arch_init(opaque);
2182 	if (r)
2183 		goto out_fail;
2184 
2185 	bad_page = alloc_page(GFP_KERNEL | __GFP_ZERO);
2186 
2187 	if (bad_page == NULL) {
2188 		r = -ENOMEM;
2189 		goto out;
2190 	}
2191 
2192 	bad_pfn = page_to_pfn(bad_page);
2193 
2194 	if (!zalloc_cpumask_var(&cpus_hardware_enabled, GFP_KERNEL)) {
2195 		r = -ENOMEM;
2196 		goto out_free_0;
2197 	}
2198 
2199 	r = kvm_arch_hardware_setup();
2200 	if (r < 0)
2201 		goto out_free_0a;
2202 
2203 	for_each_online_cpu(cpu) {
2204 		smp_call_function_single(cpu,
2205 				kvm_arch_check_processor_compat,
2206 				&r, 1);
2207 		if (r < 0)
2208 			goto out_free_1;
2209 	}
2210 
2211 	r = register_cpu_notifier(&kvm_cpu_notifier);
2212 	if (r)
2213 		goto out_free_2;
2214 	register_reboot_notifier(&kvm_reboot_notifier);
2215 
2216 	r = sysdev_class_register(&kvm_sysdev_class);
2217 	if (r)
2218 		goto out_free_3;
2219 
2220 	r = sysdev_register(&kvm_sysdev);
2221 	if (r)
2222 		goto out_free_4;
2223 
2224 	/* A kmem cache lets us meet the alignment requirements of fx_save. */
2225 	kvm_vcpu_cache = kmem_cache_create("kvm_vcpu", vcpu_size,
2226 					   __alignof__(struct kvm_vcpu),
2227 					   0, NULL);
2228 	if (!kvm_vcpu_cache) {
2229 		r = -ENOMEM;
2230 		goto out_free_5;
2231 	}
2232 
2233 	kvm_chardev_ops.owner = module;
2234 	kvm_vm_fops.owner = module;
2235 	kvm_vcpu_fops.owner = module;
2236 
2237 	r = misc_register(&kvm_dev);
2238 	if (r) {
2239 		printk(KERN_ERR "kvm: misc device register failed\n");
2240 		goto out_free;
2241 	}
2242 
2243 	kvm_preempt_ops.sched_in = kvm_sched_in;
2244 	kvm_preempt_ops.sched_out = kvm_sched_out;
2245 
2246 	kvm_init_debug();
2247 
2248 	return 0;
2249 
2250 out_free:
2251 	kmem_cache_destroy(kvm_vcpu_cache);
2252 out_free_5:
2253 	sysdev_unregister(&kvm_sysdev);
2254 out_free_4:
2255 	sysdev_class_unregister(&kvm_sysdev_class);
2256 out_free_3:
2257 	unregister_reboot_notifier(&kvm_reboot_notifier);
2258 	unregister_cpu_notifier(&kvm_cpu_notifier);
2259 out_free_2:
2260 out_free_1:
2261 	kvm_arch_hardware_unsetup();
2262 out_free_0a:
2263 	free_cpumask_var(cpus_hardware_enabled);
2264 out_free_0:
2265 	__free_page(bad_page);
2266 out:
2267 	kvm_arch_exit();
2268 out_fail:
2269 	return r;
2270 }
2271 EXPORT_SYMBOL_GPL(kvm_init);
2272 
2273 void kvm_exit(void)
2274 {
2275 	tracepoint_synchronize_unregister();
2276 	kvm_exit_debug();
2277 	misc_deregister(&kvm_dev);
2278 	kmem_cache_destroy(kvm_vcpu_cache);
2279 	sysdev_unregister(&kvm_sysdev);
2280 	sysdev_class_unregister(&kvm_sysdev_class);
2281 	unregister_reboot_notifier(&kvm_reboot_notifier);
2282 	unregister_cpu_notifier(&kvm_cpu_notifier);
2283 	on_each_cpu(hardware_disable, NULL, 1);
2284 	kvm_arch_hardware_unsetup();
2285 	kvm_arch_exit();
2286 	free_cpumask_var(cpus_hardware_enabled);
2287 	__free_page(bad_page);
2288 }
2289 EXPORT_SYMBOL_GPL(kvm_exit);
2290