1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Kernel-based Virtual Machine driver for Linux
4  *
5  * This module enables machines with Intel VT-x extensions to run virtual
6  * machines without emulation or binary translation.
7  *
8  * Copyright (C) 2006 Qumranet, Inc.
9  * Copyright 2010 Red Hat, Inc. and/or its affiliates.
10  *
11  * Authors:
12  *   Avi Kivity   <avi@qumranet.com>
13  *   Yaniv Kamay  <yaniv@qumranet.com>
14  */
15 
16 #include <kvm/iodev.h>
17 
18 #include <linux/kvm_host.h>
19 #include <linux/kvm.h>
20 #include <linux/module.h>
21 #include <linux/errno.h>
22 #include <linux/percpu.h>
23 #include <linux/mm.h>
24 #include <linux/miscdevice.h>
25 #include <linux/vmalloc.h>
26 #include <linux/reboot.h>
27 #include <linux/debugfs.h>
28 #include <linux/highmem.h>
29 #include <linux/file.h>
30 #include <linux/syscore_ops.h>
31 #include <linux/cpu.h>
32 #include <linux/sched/signal.h>
33 #include <linux/sched/mm.h>
34 #include <linux/sched/stat.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 #include <linux/sort.h>
50 #include <linux/bsearch.h>
51 #include <linux/io.h>
52 #include <linux/lockdep.h>
53 #include <linux/kthread.h>
54 #include <linux/suspend.h>
55 
56 #include <asm/processor.h>
57 #include <asm/ioctl.h>
58 #include <linux/uaccess.h>
59 
60 #include "coalesced_mmio.h"
61 #include "async_pf.h"
62 #include "kvm_mm.h"
63 #include "vfio.h"
64 
65 #include <trace/events/ipi.h>
66 
67 #define CREATE_TRACE_POINTS
68 #include <trace/events/kvm.h>
69 
70 #include <linux/kvm_dirty_ring.h>
71 
72 
73 /* Worst case buffer size needed for holding an integer. */
74 #define ITOA_MAX_LEN 12
75 
76 MODULE_AUTHOR("Qumranet");
77 MODULE_LICENSE("GPL");
78 
79 /* Architectures should define their poll value according to the halt latency */
80 unsigned int halt_poll_ns = KVM_HALT_POLL_NS_DEFAULT;
81 module_param(halt_poll_ns, uint, 0644);
82 EXPORT_SYMBOL_GPL(halt_poll_ns);
83 
84 /* Default doubles per-vcpu halt_poll_ns. */
85 unsigned int halt_poll_ns_grow = 2;
86 module_param(halt_poll_ns_grow, uint, 0644);
87 EXPORT_SYMBOL_GPL(halt_poll_ns_grow);
88 
89 /* The start value to grow halt_poll_ns from */
90 unsigned int halt_poll_ns_grow_start = 10000; /* 10us */
91 module_param(halt_poll_ns_grow_start, uint, 0644);
92 EXPORT_SYMBOL_GPL(halt_poll_ns_grow_start);
93 
94 /* Default resets per-vcpu halt_poll_ns . */
95 unsigned int halt_poll_ns_shrink;
96 module_param(halt_poll_ns_shrink, uint, 0644);
97 EXPORT_SYMBOL_GPL(halt_poll_ns_shrink);
98 
99 /*
100  * Ordering of locks:
101  *
102  *	kvm->lock --> kvm->slots_lock --> kvm->irq_lock
103  */
104 
105 DEFINE_MUTEX(kvm_lock);
106 LIST_HEAD(vm_list);
107 
108 static struct kmem_cache *kvm_vcpu_cache;
109 
110 static __read_mostly struct preempt_ops kvm_preempt_ops;
111 static DEFINE_PER_CPU(struct kvm_vcpu *, kvm_running_vcpu);
112 
113 struct dentry *kvm_debugfs_dir;
114 EXPORT_SYMBOL_GPL(kvm_debugfs_dir);
115 
116 static const struct file_operations stat_fops_per_vm;
117 
118 static struct file_operations kvm_chardev_ops;
119 
120 static long kvm_vcpu_ioctl(struct file *file, unsigned int ioctl,
121 			   unsigned long arg);
122 #ifdef CONFIG_KVM_COMPAT
123 static long kvm_vcpu_compat_ioctl(struct file *file, unsigned int ioctl,
124 				  unsigned long arg);
125 #define KVM_COMPAT(c)	.compat_ioctl	= (c)
126 #else
127 /*
128  * For architectures that don't implement a compat infrastructure,
129  * adopt a double line of defense:
130  * - Prevent a compat task from opening /dev/kvm
131  * - If the open has been done by a 64bit task, and the KVM fd
132  *   passed to a compat task, let the ioctls fail.
133  */
kvm_no_compat_ioctl(struct file * file,unsigned int ioctl,unsigned long arg)134 static long kvm_no_compat_ioctl(struct file *file, unsigned int ioctl,
135 				unsigned long arg) { return -EINVAL; }
136 
kvm_no_compat_open(struct inode * inode,struct file * file)137 static int kvm_no_compat_open(struct inode *inode, struct file *file)
138 {
139 	return is_compat_task() ? -ENODEV : 0;
140 }
141 #define KVM_COMPAT(c)	.compat_ioctl	= kvm_no_compat_ioctl,	\
142 			.open		= kvm_no_compat_open
143 #endif
144 static int hardware_enable_all(void);
145 static void hardware_disable_all(void);
146 
147 static void kvm_io_bus_destroy(struct kvm_io_bus *bus);
148 
149 #define KVM_EVENT_CREATE_VM 0
150 #define KVM_EVENT_DESTROY_VM 1
151 static void kvm_uevent_notify_change(unsigned int type, struct kvm *kvm);
152 static unsigned long long kvm_createvm_count;
153 static unsigned long long kvm_active_vms;
154 
155 static DEFINE_PER_CPU(cpumask_var_t, cpu_kick_mask);
156 
kvm_arch_guest_memory_reclaimed(struct kvm * kvm)157 __weak void kvm_arch_guest_memory_reclaimed(struct kvm *kvm)
158 {
159 }
160 
kvm_is_zone_device_page(struct page * page)161 bool kvm_is_zone_device_page(struct page *page)
162 {
163 	/*
164 	 * The metadata used by is_zone_device_page() to determine whether or
165 	 * not a page is ZONE_DEVICE is guaranteed to be valid if and only if
166 	 * the device has been pinned, e.g. by get_user_pages().  WARN if the
167 	 * page_count() is zero to help detect bad usage of this helper.
168 	 */
169 	if (WARN_ON_ONCE(!page_count(page)))
170 		return false;
171 
172 	return is_zone_device_page(page);
173 }
174 
175 /*
176  * Returns a 'struct page' if the pfn is "valid" and backed by a refcounted
177  * page, NULL otherwise.  Note, the list of refcounted PG_reserved page types
178  * is likely incomplete, it has been compiled purely through people wanting to
179  * back guest with a certain type of memory and encountering issues.
180  */
kvm_pfn_to_refcounted_page(kvm_pfn_t pfn)181 struct page *kvm_pfn_to_refcounted_page(kvm_pfn_t pfn)
182 {
183 	struct page *page;
184 
185 	if (!pfn_valid(pfn))
186 		return NULL;
187 
188 	page = pfn_to_page(pfn);
189 	if (!PageReserved(page))
190 		return page;
191 
192 	/* The ZERO_PAGE(s) is marked PG_reserved, but is refcounted. */
193 	if (is_zero_pfn(pfn))
194 		return page;
195 
196 	/*
197 	 * ZONE_DEVICE pages currently set PG_reserved, but from a refcounting
198 	 * perspective they are "normal" pages, albeit with slightly different
199 	 * usage rules.
200 	 */
201 	if (kvm_is_zone_device_page(page))
202 		return page;
203 
204 	return NULL;
205 }
206 
207 /*
208  * Switches to specified vcpu, until a matching vcpu_put()
209  */
vcpu_load(struct kvm_vcpu * vcpu)210 void vcpu_load(struct kvm_vcpu *vcpu)
211 {
212 	int cpu = get_cpu();
213 
214 	__this_cpu_write(kvm_running_vcpu, vcpu);
215 	preempt_notifier_register(&vcpu->preempt_notifier);
216 	kvm_arch_vcpu_load(vcpu, cpu);
217 	put_cpu();
218 }
219 EXPORT_SYMBOL_GPL(vcpu_load);
220 
vcpu_put(struct kvm_vcpu * vcpu)221 void vcpu_put(struct kvm_vcpu *vcpu)
222 {
223 	preempt_disable();
224 	kvm_arch_vcpu_put(vcpu);
225 	preempt_notifier_unregister(&vcpu->preempt_notifier);
226 	__this_cpu_write(kvm_running_vcpu, NULL);
227 	preempt_enable();
228 }
229 EXPORT_SYMBOL_GPL(vcpu_put);
230 
231 /* TODO: merge with kvm_arch_vcpu_should_kick */
kvm_request_needs_ipi(struct kvm_vcpu * vcpu,unsigned req)232 static bool kvm_request_needs_ipi(struct kvm_vcpu *vcpu, unsigned req)
233 {
234 	int mode = kvm_vcpu_exiting_guest_mode(vcpu);
235 
236 	/*
237 	 * We need to wait for the VCPU to reenable interrupts and get out of
238 	 * READING_SHADOW_PAGE_TABLES mode.
239 	 */
240 	if (req & KVM_REQUEST_WAIT)
241 		return mode != OUTSIDE_GUEST_MODE;
242 
243 	/*
244 	 * Need to kick a running VCPU, but otherwise there is nothing to do.
245 	 */
246 	return mode == IN_GUEST_MODE;
247 }
248 
ack_kick(void * _completed)249 static void ack_kick(void *_completed)
250 {
251 }
252 
kvm_kick_many_cpus(struct cpumask * cpus,bool wait)253 static inline bool kvm_kick_many_cpus(struct cpumask *cpus, bool wait)
254 {
255 	if (cpumask_empty(cpus))
256 		return false;
257 
258 	smp_call_function_many(cpus, ack_kick, NULL, wait);
259 	return true;
260 }
261 
kvm_make_vcpu_request(struct kvm_vcpu * vcpu,unsigned int req,struct cpumask * tmp,int current_cpu)262 static void kvm_make_vcpu_request(struct kvm_vcpu *vcpu, unsigned int req,
263 				  struct cpumask *tmp, int current_cpu)
264 {
265 	int cpu;
266 
267 	if (likely(!(req & KVM_REQUEST_NO_ACTION)))
268 		__kvm_make_request(req, vcpu);
269 
270 	if (!(req & KVM_REQUEST_NO_WAKEUP) && kvm_vcpu_wake_up(vcpu))
271 		return;
272 
273 	/*
274 	 * Note, the vCPU could get migrated to a different pCPU at any point
275 	 * after kvm_request_needs_ipi(), which could result in sending an IPI
276 	 * to the previous pCPU.  But, that's OK because the purpose of the IPI
277 	 * is to ensure the vCPU returns to OUTSIDE_GUEST_MODE, which is
278 	 * satisfied if the vCPU migrates. Entering READING_SHADOW_PAGE_TABLES
279 	 * after this point is also OK, as the requirement is only that KVM wait
280 	 * for vCPUs that were reading SPTEs _before_ any changes were
281 	 * finalized. See kvm_vcpu_kick() for more details on handling requests.
282 	 */
283 	if (kvm_request_needs_ipi(vcpu, req)) {
284 		cpu = READ_ONCE(vcpu->cpu);
285 		if (cpu != -1 && cpu != current_cpu)
286 			__cpumask_set_cpu(cpu, tmp);
287 	}
288 }
289 
kvm_make_vcpus_request_mask(struct kvm * kvm,unsigned int req,unsigned long * vcpu_bitmap)290 bool kvm_make_vcpus_request_mask(struct kvm *kvm, unsigned int req,
291 				 unsigned long *vcpu_bitmap)
292 {
293 	struct kvm_vcpu *vcpu;
294 	struct cpumask *cpus;
295 	int i, me;
296 	bool called;
297 
298 	me = get_cpu();
299 
300 	cpus = this_cpu_cpumask_var_ptr(cpu_kick_mask);
301 	cpumask_clear(cpus);
302 
303 	for_each_set_bit(i, vcpu_bitmap, KVM_MAX_VCPUS) {
304 		vcpu = kvm_get_vcpu(kvm, i);
305 		if (!vcpu)
306 			continue;
307 		kvm_make_vcpu_request(vcpu, req, cpus, me);
308 	}
309 
310 	called = kvm_kick_many_cpus(cpus, !!(req & KVM_REQUEST_WAIT));
311 	put_cpu();
312 
313 	return called;
314 }
315 
kvm_make_all_cpus_request_except(struct kvm * kvm,unsigned int req,struct kvm_vcpu * except)316 bool kvm_make_all_cpus_request_except(struct kvm *kvm, unsigned int req,
317 				      struct kvm_vcpu *except)
318 {
319 	struct kvm_vcpu *vcpu;
320 	struct cpumask *cpus;
321 	unsigned long i;
322 	bool called;
323 	int me;
324 
325 	me = get_cpu();
326 
327 	cpus = this_cpu_cpumask_var_ptr(cpu_kick_mask);
328 	cpumask_clear(cpus);
329 
330 	kvm_for_each_vcpu(i, vcpu, kvm) {
331 		if (vcpu == except)
332 			continue;
333 		kvm_make_vcpu_request(vcpu, req, cpus, me);
334 	}
335 
336 	called = kvm_kick_many_cpus(cpus, !!(req & KVM_REQUEST_WAIT));
337 	put_cpu();
338 
339 	return called;
340 }
341 
kvm_make_all_cpus_request(struct kvm * kvm,unsigned int req)342 bool kvm_make_all_cpus_request(struct kvm *kvm, unsigned int req)
343 {
344 	return kvm_make_all_cpus_request_except(kvm, req, NULL);
345 }
346 EXPORT_SYMBOL_GPL(kvm_make_all_cpus_request);
347 
kvm_flush_remote_tlbs(struct kvm * kvm)348 void kvm_flush_remote_tlbs(struct kvm *kvm)
349 {
350 	++kvm->stat.generic.remote_tlb_flush_requests;
351 
352 	/*
353 	 * We want to publish modifications to the page tables before reading
354 	 * mode. Pairs with a memory barrier in arch-specific code.
355 	 * - x86: smp_mb__after_srcu_read_unlock in vcpu_enter_guest
356 	 * and smp_mb in walk_shadow_page_lockless_begin/end.
357 	 * - powerpc: smp_mb in kvmppc_prepare_to_enter.
358 	 *
359 	 * There is already an smp_mb__after_atomic() before
360 	 * kvm_make_all_cpus_request() reads vcpu->mode. We reuse that
361 	 * barrier here.
362 	 */
363 	if (!kvm_arch_flush_remote_tlbs(kvm)
364 	    || kvm_make_all_cpus_request(kvm, KVM_REQ_TLB_FLUSH))
365 		++kvm->stat.generic.remote_tlb_flush;
366 }
367 EXPORT_SYMBOL_GPL(kvm_flush_remote_tlbs);
368 
kvm_flush_remote_tlbs_range(struct kvm * kvm,gfn_t gfn,u64 nr_pages)369 void kvm_flush_remote_tlbs_range(struct kvm *kvm, gfn_t gfn, u64 nr_pages)
370 {
371 	if (!kvm_arch_flush_remote_tlbs_range(kvm, gfn, nr_pages))
372 		return;
373 
374 	/*
375 	 * Fall back to a flushing entire TLBs if the architecture range-based
376 	 * TLB invalidation is unsupported or can't be performed for whatever
377 	 * reason.
378 	 */
379 	kvm_flush_remote_tlbs(kvm);
380 }
381 
kvm_flush_remote_tlbs_memslot(struct kvm * kvm,const struct kvm_memory_slot * memslot)382 void kvm_flush_remote_tlbs_memslot(struct kvm *kvm,
383 				   const struct kvm_memory_slot *memslot)
384 {
385 	/*
386 	 * All current use cases for flushing the TLBs for a specific memslot
387 	 * are related to dirty logging, and many do the TLB flush out of
388 	 * mmu_lock. The interaction between the various operations on memslot
389 	 * must be serialized by slots_locks to ensure the TLB flush from one
390 	 * operation is observed by any other operation on the same memslot.
391 	 */
392 	lockdep_assert_held(&kvm->slots_lock);
393 	kvm_flush_remote_tlbs_range(kvm, memslot->base_gfn, memslot->npages);
394 }
395 
kvm_flush_shadow_all(struct kvm * kvm)396 static void kvm_flush_shadow_all(struct kvm *kvm)
397 {
398 	kvm_arch_flush_shadow_all(kvm);
399 	kvm_arch_guest_memory_reclaimed(kvm);
400 }
401 
402 #ifdef KVM_ARCH_NR_OBJS_PER_MEMORY_CACHE
mmu_memory_cache_alloc_obj(struct kvm_mmu_memory_cache * mc,gfp_t gfp_flags)403 static inline void *mmu_memory_cache_alloc_obj(struct kvm_mmu_memory_cache *mc,
404 					       gfp_t gfp_flags)
405 {
406 	gfp_flags |= mc->gfp_zero;
407 
408 	if (mc->kmem_cache)
409 		return kmem_cache_alloc(mc->kmem_cache, gfp_flags);
410 	else
411 		return (void *)__get_free_page(gfp_flags);
412 }
413 
__kvm_mmu_topup_memory_cache(struct kvm_mmu_memory_cache * mc,int capacity,int min)414 int __kvm_mmu_topup_memory_cache(struct kvm_mmu_memory_cache *mc, int capacity, int min)
415 {
416 	gfp_t gfp = mc->gfp_custom ? mc->gfp_custom : GFP_KERNEL_ACCOUNT;
417 	void *obj;
418 
419 	if (mc->nobjs >= min)
420 		return 0;
421 
422 	if (unlikely(!mc->objects)) {
423 		if (WARN_ON_ONCE(!capacity))
424 			return -EIO;
425 
426 		mc->objects = kvmalloc_array(sizeof(void *), capacity, gfp);
427 		if (!mc->objects)
428 			return -ENOMEM;
429 
430 		mc->capacity = capacity;
431 	}
432 
433 	/* It is illegal to request a different capacity across topups. */
434 	if (WARN_ON_ONCE(mc->capacity != capacity))
435 		return -EIO;
436 
437 	while (mc->nobjs < mc->capacity) {
438 		obj = mmu_memory_cache_alloc_obj(mc, gfp);
439 		if (!obj)
440 			return mc->nobjs >= min ? 0 : -ENOMEM;
441 		mc->objects[mc->nobjs++] = obj;
442 	}
443 	return 0;
444 }
445 
kvm_mmu_topup_memory_cache(struct kvm_mmu_memory_cache * mc,int min)446 int kvm_mmu_topup_memory_cache(struct kvm_mmu_memory_cache *mc, int min)
447 {
448 	return __kvm_mmu_topup_memory_cache(mc, KVM_ARCH_NR_OBJS_PER_MEMORY_CACHE, min);
449 }
450 
kvm_mmu_memory_cache_nr_free_objects(struct kvm_mmu_memory_cache * mc)451 int kvm_mmu_memory_cache_nr_free_objects(struct kvm_mmu_memory_cache *mc)
452 {
453 	return mc->nobjs;
454 }
455 
kvm_mmu_free_memory_cache(struct kvm_mmu_memory_cache * mc)456 void kvm_mmu_free_memory_cache(struct kvm_mmu_memory_cache *mc)
457 {
458 	while (mc->nobjs) {
459 		if (mc->kmem_cache)
460 			kmem_cache_free(mc->kmem_cache, mc->objects[--mc->nobjs]);
461 		else
462 			free_page((unsigned long)mc->objects[--mc->nobjs]);
463 	}
464 
465 	kvfree(mc->objects);
466 
467 	mc->objects = NULL;
468 	mc->capacity = 0;
469 }
470 
kvm_mmu_memory_cache_alloc(struct kvm_mmu_memory_cache * mc)471 void *kvm_mmu_memory_cache_alloc(struct kvm_mmu_memory_cache *mc)
472 {
473 	void *p;
474 
475 	if (WARN_ON(!mc->nobjs))
476 		p = mmu_memory_cache_alloc_obj(mc, GFP_ATOMIC | __GFP_ACCOUNT);
477 	else
478 		p = mc->objects[--mc->nobjs];
479 	BUG_ON(!p);
480 	return p;
481 }
482 #endif
483 
kvm_vcpu_init(struct kvm_vcpu * vcpu,struct kvm * kvm,unsigned id)484 static void kvm_vcpu_init(struct kvm_vcpu *vcpu, struct kvm *kvm, unsigned id)
485 {
486 	mutex_init(&vcpu->mutex);
487 	vcpu->cpu = -1;
488 	vcpu->kvm = kvm;
489 	vcpu->vcpu_id = id;
490 	vcpu->pid = NULL;
491 #ifndef __KVM_HAVE_ARCH_WQP
492 	rcuwait_init(&vcpu->wait);
493 #endif
494 	kvm_async_pf_vcpu_init(vcpu);
495 
496 	kvm_vcpu_set_in_spin_loop(vcpu, false);
497 	kvm_vcpu_set_dy_eligible(vcpu, false);
498 	vcpu->preempted = false;
499 	vcpu->ready = false;
500 	preempt_notifier_init(&vcpu->preempt_notifier, &kvm_preempt_ops);
501 	vcpu->last_used_slot = NULL;
502 
503 	/* Fill the stats id string for the vcpu */
504 	snprintf(vcpu->stats_id, sizeof(vcpu->stats_id), "kvm-%d/vcpu-%d",
505 		 task_pid_nr(current), id);
506 }
507 
kvm_vcpu_destroy(struct kvm_vcpu * vcpu)508 static void kvm_vcpu_destroy(struct kvm_vcpu *vcpu)
509 {
510 	kvm_arch_vcpu_destroy(vcpu);
511 	kvm_dirty_ring_free(&vcpu->dirty_ring);
512 
513 	/*
514 	 * No need for rcu_read_lock as VCPU_RUN is the only place that changes
515 	 * the vcpu->pid pointer, and at destruction time all file descriptors
516 	 * are already gone.
517 	 */
518 	put_pid(rcu_dereference_protected(vcpu->pid, 1));
519 
520 	free_page((unsigned long)vcpu->run);
521 	kmem_cache_free(kvm_vcpu_cache, vcpu);
522 }
523 
kvm_destroy_vcpus(struct kvm * kvm)524 void kvm_destroy_vcpus(struct kvm *kvm)
525 {
526 	unsigned long i;
527 	struct kvm_vcpu *vcpu;
528 
529 	kvm_for_each_vcpu(i, vcpu, kvm) {
530 		kvm_vcpu_destroy(vcpu);
531 		xa_erase(&kvm->vcpu_array, i);
532 	}
533 
534 	atomic_set(&kvm->online_vcpus, 0);
535 }
536 EXPORT_SYMBOL_GPL(kvm_destroy_vcpus);
537 
538 #if defined(CONFIG_MMU_NOTIFIER) && defined(KVM_ARCH_WANT_MMU_NOTIFIER)
mmu_notifier_to_kvm(struct mmu_notifier * mn)539 static inline struct kvm *mmu_notifier_to_kvm(struct mmu_notifier *mn)
540 {
541 	return container_of(mn, struct kvm, mmu_notifier);
542 }
543 
544 typedef bool (*hva_handler_t)(struct kvm *kvm, struct kvm_gfn_range *range);
545 
546 typedef void (*on_lock_fn_t)(struct kvm *kvm, unsigned long start,
547 			     unsigned long end);
548 
549 typedef void (*on_unlock_fn_t)(struct kvm *kvm);
550 
551 struct kvm_hva_range {
552 	unsigned long start;
553 	unsigned long end;
554 	union kvm_mmu_notifier_arg arg;
555 	hva_handler_t handler;
556 	on_lock_fn_t on_lock;
557 	on_unlock_fn_t on_unlock;
558 	bool flush_on_ret;
559 	bool may_block;
560 };
561 
562 /*
563  * Use a dedicated stub instead of NULL to indicate that there is no callback
564  * function/handler.  The compiler technically can't guarantee that a real
565  * function will have a non-zero address, and so it will generate code to
566  * check for !NULL, whereas comparing against a stub will be elided at compile
567  * time (unless the compiler is getting long in the tooth, e.g. gcc 4.9).
568  */
kvm_null_fn(void)569 static void kvm_null_fn(void)
570 {
571 
572 }
573 #define IS_KVM_NULL_FN(fn) ((fn) == (void *)kvm_null_fn)
574 
575 static const union kvm_mmu_notifier_arg KVM_MMU_NOTIFIER_NO_ARG;
576 
577 /* Iterate over each memslot intersecting [start, last] (inclusive) range */
578 #define kvm_for_each_memslot_in_hva_range(node, slots, start, last)	     \
579 	for (node = interval_tree_iter_first(&slots->hva_tree, start, last); \
580 	     node;							     \
581 	     node = interval_tree_iter_next(node, start, last))	     \
582 
__kvm_handle_hva_range(struct kvm * kvm,const struct kvm_hva_range * range)583 static __always_inline int __kvm_handle_hva_range(struct kvm *kvm,
584 						  const struct kvm_hva_range *range)
585 {
586 	bool ret = false, locked = false;
587 	struct kvm_gfn_range gfn_range;
588 	struct kvm_memory_slot *slot;
589 	struct kvm_memslots *slots;
590 	int i, idx;
591 
592 	if (WARN_ON_ONCE(range->end <= range->start))
593 		return 0;
594 
595 	/* A null handler is allowed if and only if on_lock() is provided. */
596 	if (WARN_ON_ONCE(IS_KVM_NULL_FN(range->on_lock) &&
597 			 IS_KVM_NULL_FN(range->handler)))
598 		return 0;
599 
600 	idx = srcu_read_lock(&kvm->srcu);
601 
602 	for (i = 0; i < KVM_ADDRESS_SPACE_NUM; i++) {
603 		struct interval_tree_node *node;
604 
605 		slots = __kvm_memslots(kvm, i);
606 		kvm_for_each_memslot_in_hva_range(node, slots,
607 						  range->start, range->end - 1) {
608 			unsigned long hva_start, hva_end;
609 
610 			slot = container_of(node, struct kvm_memory_slot, hva_node[slots->node_idx]);
611 			hva_start = max(range->start, slot->userspace_addr);
612 			hva_end = min(range->end, slot->userspace_addr +
613 						  (slot->npages << PAGE_SHIFT));
614 
615 			/*
616 			 * To optimize for the likely case where the address
617 			 * range is covered by zero or one memslots, don't
618 			 * bother making these conditional (to avoid writes on
619 			 * the second or later invocation of the handler).
620 			 */
621 			gfn_range.arg = range->arg;
622 			gfn_range.may_block = range->may_block;
623 
624 			/*
625 			 * {gfn(page) | page intersects with [hva_start, hva_end)} =
626 			 * {gfn_start, gfn_start+1, ..., gfn_end-1}.
627 			 */
628 			gfn_range.start = hva_to_gfn_memslot(hva_start, slot);
629 			gfn_range.end = hva_to_gfn_memslot(hva_end + PAGE_SIZE - 1, slot);
630 			gfn_range.slot = slot;
631 
632 			if (!locked) {
633 				locked = true;
634 				KVM_MMU_LOCK(kvm);
635 				if (!IS_KVM_NULL_FN(range->on_lock))
636 					range->on_lock(kvm, range->start, range->end);
637 				if (IS_KVM_NULL_FN(range->handler))
638 					break;
639 			}
640 			ret |= range->handler(kvm, &gfn_range);
641 		}
642 	}
643 
644 	if (range->flush_on_ret && ret)
645 		kvm_flush_remote_tlbs(kvm);
646 
647 	if (locked) {
648 		KVM_MMU_UNLOCK(kvm);
649 		if (!IS_KVM_NULL_FN(range->on_unlock))
650 			range->on_unlock(kvm);
651 	}
652 
653 	srcu_read_unlock(&kvm->srcu, idx);
654 
655 	/* The notifiers are averse to booleans. :-( */
656 	return (int)ret;
657 }
658 
kvm_handle_hva_range(struct mmu_notifier * mn,unsigned long start,unsigned long end,union kvm_mmu_notifier_arg arg,hva_handler_t handler)659 static __always_inline int kvm_handle_hva_range(struct mmu_notifier *mn,
660 						unsigned long start,
661 						unsigned long end,
662 						union kvm_mmu_notifier_arg arg,
663 						hva_handler_t handler)
664 {
665 	struct kvm *kvm = mmu_notifier_to_kvm(mn);
666 	const struct kvm_hva_range range = {
667 		.start		= start,
668 		.end		= end,
669 		.arg		= arg,
670 		.handler	= handler,
671 		.on_lock	= (void *)kvm_null_fn,
672 		.on_unlock	= (void *)kvm_null_fn,
673 		.flush_on_ret	= true,
674 		.may_block	= false,
675 	};
676 
677 	return __kvm_handle_hva_range(kvm, &range);
678 }
679 
kvm_handle_hva_range_no_flush(struct mmu_notifier * mn,unsigned long start,unsigned long end,hva_handler_t handler)680 static __always_inline int kvm_handle_hva_range_no_flush(struct mmu_notifier *mn,
681 							 unsigned long start,
682 							 unsigned long end,
683 							 hva_handler_t handler)
684 {
685 	struct kvm *kvm = mmu_notifier_to_kvm(mn);
686 	const struct kvm_hva_range range = {
687 		.start		= start,
688 		.end		= end,
689 		.handler	= handler,
690 		.on_lock	= (void *)kvm_null_fn,
691 		.on_unlock	= (void *)kvm_null_fn,
692 		.flush_on_ret	= false,
693 		.may_block	= false,
694 	};
695 
696 	return __kvm_handle_hva_range(kvm, &range);
697 }
698 
kvm_change_spte_gfn(struct kvm * kvm,struct kvm_gfn_range * range)699 static bool kvm_change_spte_gfn(struct kvm *kvm, struct kvm_gfn_range *range)
700 {
701 	/*
702 	 * Skipping invalid memslots is correct if and only change_pte() is
703 	 * surrounded by invalidate_range_{start,end}(), which is currently
704 	 * guaranteed by the primary MMU.  If that ever changes, KVM needs to
705 	 * unmap the memslot instead of skipping the memslot to ensure that KVM
706 	 * doesn't hold references to the old PFN.
707 	 */
708 	WARN_ON_ONCE(!READ_ONCE(kvm->mn_active_invalidate_count));
709 
710 	if (range->slot->flags & KVM_MEMSLOT_INVALID)
711 		return false;
712 
713 	return kvm_set_spte_gfn(kvm, range);
714 }
715 
kvm_mmu_notifier_change_pte(struct mmu_notifier * mn,struct mm_struct * mm,unsigned long address,pte_t pte)716 static void kvm_mmu_notifier_change_pte(struct mmu_notifier *mn,
717 					struct mm_struct *mm,
718 					unsigned long address,
719 					pte_t pte)
720 {
721 	struct kvm *kvm = mmu_notifier_to_kvm(mn);
722 	const union kvm_mmu_notifier_arg arg = { .pte = pte };
723 
724 	trace_kvm_set_spte_hva(address);
725 
726 	/*
727 	 * .change_pte() must be surrounded by .invalidate_range_{start,end}().
728 	 * If mmu_invalidate_in_progress is zero, then no in-progress
729 	 * invalidations, including this one, found a relevant memslot at
730 	 * start(); rechecking memslots here is unnecessary.  Note, a false
731 	 * positive (count elevated by a different invalidation) is sub-optimal
732 	 * but functionally ok.
733 	 */
734 	WARN_ON_ONCE(!READ_ONCE(kvm->mn_active_invalidate_count));
735 	if (!READ_ONCE(kvm->mmu_invalidate_in_progress))
736 		return;
737 
738 	kvm_handle_hva_range(mn, address, address + 1, arg, kvm_change_spte_gfn);
739 }
740 
kvm_mmu_invalidate_begin(struct kvm * kvm,unsigned long start,unsigned long end)741 void kvm_mmu_invalidate_begin(struct kvm *kvm, unsigned long start,
742 			      unsigned long end)
743 {
744 	/*
745 	 * The count increase must become visible at unlock time as no
746 	 * spte can be established without taking the mmu_lock and
747 	 * count is also read inside the mmu_lock critical section.
748 	 */
749 	kvm->mmu_invalidate_in_progress++;
750 	if (likely(kvm->mmu_invalidate_in_progress == 1)) {
751 		kvm->mmu_invalidate_range_start = start;
752 		kvm->mmu_invalidate_range_end = end;
753 	} else {
754 		/*
755 		 * Fully tracking multiple concurrent ranges has diminishing
756 		 * returns. Keep things simple and just find the minimal range
757 		 * which includes the current and new ranges. As there won't be
758 		 * enough information to subtract a range after its invalidate
759 		 * completes, any ranges invalidated concurrently will
760 		 * accumulate and persist until all outstanding invalidates
761 		 * complete.
762 		 */
763 		kvm->mmu_invalidate_range_start =
764 			min(kvm->mmu_invalidate_range_start, start);
765 		kvm->mmu_invalidate_range_end =
766 			max(kvm->mmu_invalidate_range_end, end);
767 	}
768 }
769 
kvm_mmu_notifier_invalidate_range_start(struct mmu_notifier * mn,const struct mmu_notifier_range * range)770 static int kvm_mmu_notifier_invalidate_range_start(struct mmu_notifier *mn,
771 					const struct mmu_notifier_range *range)
772 {
773 	struct kvm *kvm = mmu_notifier_to_kvm(mn);
774 	const struct kvm_hva_range hva_range = {
775 		.start		= range->start,
776 		.end		= range->end,
777 		.handler	= kvm_unmap_gfn_range,
778 		.on_lock	= kvm_mmu_invalidate_begin,
779 		.on_unlock	= kvm_arch_guest_memory_reclaimed,
780 		.flush_on_ret	= true,
781 		.may_block	= mmu_notifier_range_blockable(range),
782 	};
783 
784 	trace_kvm_unmap_hva_range(range->start, range->end);
785 
786 	/*
787 	 * Prevent memslot modification between range_start() and range_end()
788 	 * so that conditionally locking provides the same result in both
789 	 * functions.  Without that guarantee, the mmu_invalidate_in_progress
790 	 * adjustments will be imbalanced.
791 	 *
792 	 * Pairs with the decrement in range_end().
793 	 */
794 	spin_lock(&kvm->mn_invalidate_lock);
795 	kvm->mn_active_invalidate_count++;
796 	spin_unlock(&kvm->mn_invalidate_lock);
797 
798 	/*
799 	 * Invalidate pfn caches _before_ invalidating the secondary MMUs, i.e.
800 	 * before acquiring mmu_lock, to avoid holding mmu_lock while acquiring
801 	 * each cache's lock.  There are relatively few caches in existence at
802 	 * any given time, and the caches themselves can check for hva overlap,
803 	 * i.e. don't need to rely on memslot overlap checks for performance.
804 	 * Because this runs without holding mmu_lock, the pfn caches must use
805 	 * mn_active_invalidate_count (see above) instead of
806 	 * mmu_invalidate_in_progress.
807 	 */
808 	gfn_to_pfn_cache_invalidate_start(kvm, range->start, range->end,
809 					  hva_range.may_block);
810 
811 	__kvm_handle_hva_range(kvm, &hva_range);
812 
813 	return 0;
814 }
815 
kvm_mmu_invalidate_end(struct kvm * kvm,unsigned long start,unsigned long end)816 void kvm_mmu_invalidate_end(struct kvm *kvm, unsigned long start,
817 			    unsigned long end)
818 {
819 	/*
820 	 * This sequence increase will notify the kvm page fault that
821 	 * the page that is going to be mapped in the spte could have
822 	 * been freed.
823 	 */
824 	kvm->mmu_invalidate_seq++;
825 	smp_wmb();
826 	/*
827 	 * The above sequence increase must be visible before the
828 	 * below count decrease, which is ensured by the smp_wmb above
829 	 * in conjunction with the smp_rmb in mmu_invalidate_retry().
830 	 */
831 	kvm->mmu_invalidate_in_progress--;
832 }
833 
kvm_mmu_notifier_invalidate_range_end(struct mmu_notifier * mn,const struct mmu_notifier_range * range)834 static void kvm_mmu_notifier_invalidate_range_end(struct mmu_notifier *mn,
835 					const struct mmu_notifier_range *range)
836 {
837 	struct kvm *kvm = mmu_notifier_to_kvm(mn);
838 	const struct kvm_hva_range hva_range = {
839 		.start		= range->start,
840 		.end		= range->end,
841 		.handler	= (void *)kvm_null_fn,
842 		.on_lock	= kvm_mmu_invalidate_end,
843 		.on_unlock	= (void *)kvm_null_fn,
844 		.flush_on_ret	= false,
845 		.may_block	= mmu_notifier_range_blockable(range),
846 	};
847 	bool wake;
848 
849 	__kvm_handle_hva_range(kvm, &hva_range);
850 
851 	/* Pairs with the increment in range_start(). */
852 	spin_lock(&kvm->mn_invalidate_lock);
853 	wake = (--kvm->mn_active_invalidate_count == 0);
854 	spin_unlock(&kvm->mn_invalidate_lock);
855 
856 	/*
857 	 * There can only be one waiter, since the wait happens under
858 	 * slots_lock.
859 	 */
860 	if (wake)
861 		rcuwait_wake_up(&kvm->mn_memslots_update_rcuwait);
862 
863 	BUG_ON(kvm->mmu_invalidate_in_progress < 0);
864 }
865 
kvm_mmu_notifier_clear_flush_young(struct mmu_notifier * mn,struct mm_struct * mm,unsigned long start,unsigned long end)866 static int kvm_mmu_notifier_clear_flush_young(struct mmu_notifier *mn,
867 					      struct mm_struct *mm,
868 					      unsigned long start,
869 					      unsigned long end)
870 {
871 	trace_kvm_age_hva(start, end);
872 
873 	return kvm_handle_hva_range(mn, start, end, KVM_MMU_NOTIFIER_NO_ARG,
874 				    kvm_age_gfn);
875 }
876 
kvm_mmu_notifier_clear_young(struct mmu_notifier * mn,struct mm_struct * mm,unsigned long start,unsigned long end)877 static int kvm_mmu_notifier_clear_young(struct mmu_notifier *mn,
878 					struct mm_struct *mm,
879 					unsigned long start,
880 					unsigned long end)
881 {
882 	trace_kvm_age_hva(start, end);
883 
884 	/*
885 	 * Even though we do not flush TLB, this will still adversely
886 	 * affect performance on pre-Haswell Intel EPT, where there is
887 	 * no EPT Access Bit to clear so that we have to tear down EPT
888 	 * tables instead. If we find this unacceptable, we can always
889 	 * add a parameter to kvm_age_hva so that it effectively doesn't
890 	 * do anything on clear_young.
891 	 *
892 	 * Also note that currently we never issue secondary TLB flushes
893 	 * from clear_young, leaving this job up to the regular system
894 	 * cadence. If we find this inaccurate, we might come up with a
895 	 * more sophisticated heuristic later.
896 	 */
897 	return kvm_handle_hva_range_no_flush(mn, start, end, kvm_age_gfn);
898 }
899 
kvm_mmu_notifier_test_young(struct mmu_notifier * mn,struct mm_struct * mm,unsigned long address)900 static int kvm_mmu_notifier_test_young(struct mmu_notifier *mn,
901 				       struct mm_struct *mm,
902 				       unsigned long address)
903 {
904 	trace_kvm_test_age_hva(address);
905 
906 	return kvm_handle_hva_range_no_flush(mn, address, address + 1,
907 					     kvm_test_age_gfn);
908 }
909 
kvm_mmu_notifier_release(struct mmu_notifier * mn,struct mm_struct * mm)910 static void kvm_mmu_notifier_release(struct mmu_notifier *mn,
911 				     struct mm_struct *mm)
912 {
913 	struct kvm *kvm = mmu_notifier_to_kvm(mn);
914 	int idx;
915 
916 	idx = srcu_read_lock(&kvm->srcu);
917 	kvm_flush_shadow_all(kvm);
918 	srcu_read_unlock(&kvm->srcu, idx);
919 }
920 
921 static const struct mmu_notifier_ops kvm_mmu_notifier_ops = {
922 	.invalidate_range_start	= kvm_mmu_notifier_invalidate_range_start,
923 	.invalidate_range_end	= kvm_mmu_notifier_invalidate_range_end,
924 	.clear_flush_young	= kvm_mmu_notifier_clear_flush_young,
925 	.clear_young		= kvm_mmu_notifier_clear_young,
926 	.test_young		= kvm_mmu_notifier_test_young,
927 	.change_pte		= kvm_mmu_notifier_change_pte,
928 	.release		= kvm_mmu_notifier_release,
929 };
930 
kvm_init_mmu_notifier(struct kvm * kvm)931 static int kvm_init_mmu_notifier(struct kvm *kvm)
932 {
933 	kvm->mmu_notifier.ops = &kvm_mmu_notifier_ops;
934 	return mmu_notifier_register(&kvm->mmu_notifier, current->mm);
935 }
936 
937 #else  /* !(CONFIG_MMU_NOTIFIER && KVM_ARCH_WANT_MMU_NOTIFIER) */
938 
kvm_init_mmu_notifier(struct kvm * kvm)939 static int kvm_init_mmu_notifier(struct kvm *kvm)
940 {
941 	return 0;
942 }
943 
944 #endif /* CONFIG_MMU_NOTIFIER && KVM_ARCH_WANT_MMU_NOTIFIER */
945 
946 #ifdef CONFIG_HAVE_KVM_PM_NOTIFIER
kvm_pm_notifier_call(struct notifier_block * bl,unsigned long state,void * unused)947 static int kvm_pm_notifier_call(struct notifier_block *bl,
948 				unsigned long state,
949 				void *unused)
950 {
951 	struct kvm *kvm = container_of(bl, struct kvm, pm_notifier);
952 
953 	return kvm_arch_pm_notifier(kvm, state);
954 }
955 
kvm_init_pm_notifier(struct kvm * kvm)956 static void kvm_init_pm_notifier(struct kvm *kvm)
957 {
958 	kvm->pm_notifier.notifier_call = kvm_pm_notifier_call;
959 	/* Suspend KVM before we suspend ftrace, RCU, etc. */
960 	kvm->pm_notifier.priority = INT_MAX;
961 	register_pm_notifier(&kvm->pm_notifier);
962 }
963 
kvm_destroy_pm_notifier(struct kvm * kvm)964 static void kvm_destroy_pm_notifier(struct kvm *kvm)
965 {
966 	unregister_pm_notifier(&kvm->pm_notifier);
967 }
968 #else /* !CONFIG_HAVE_KVM_PM_NOTIFIER */
kvm_init_pm_notifier(struct kvm * kvm)969 static void kvm_init_pm_notifier(struct kvm *kvm)
970 {
971 }
972 
kvm_destroy_pm_notifier(struct kvm * kvm)973 static void kvm_destroy_pm_notifier(struct kvm *kvm)
974 {
975 }
976 #endif /* CONFIG_HAVE_KVM_PM_NOTIFIER */
977 
kvm_destroy_dirty_bitmap(struct kvm_memory_slot * memslot)978 static void kvm_destroy_dirty_bitmap(struct kvm_memory_slot *memslot)
979 {
980 	if (!memslot->dirty_bitmap)
981 		return;
982 
983 	kvfree(memslot->dirty_bitmap);
984 	memslot->dirty_bitmap = NULL;
985 }
986 
987 /* This does not remove the slot from struct kvm_memslots data structures */
kvm_free_memslot(struct kvm * kvm,struct kvm_memory_slot * slot)988 static void kvm_free_memslot(struct kvm *kvm, struct kvm_memory_slot *slot)
989 {
990 	kvm_destroy_dirty_bitmap(slot);
991 
992 	kvm_arch_free_memslot(kvm, slot);
993 
994 	kfree(slot);
995 }
996 
kvm_free_memslots(struct kvm * kvm,struct kvm_memslots * slots)997 static void kvm_free_memslots(struct kvm *kvm, struct kvm_memslots *slots)
998 {
999 	struct hlist_node *idnode;
1000 	struct kvm_memory_slot *memslot;
1001 	int bkt;
1002 
1003 	/*
1004 	 * The same memslot objects live in both active and inactive sets,
1005 	 * arbitrarily free using index '1' so the second invocation of this
1006 	 * function isn't operating over a structure with dangling pointers
1007 	 * (even though this function isn't actually touching them).
1008 	 */
1009 	if (!slots->node_idx)
1010 		return;
1011 
1012 	hash_for_each_safe(slots->id_hash, bkt, idnode, memslot, id_node[1])
1013 		kvm_free_memslot(kvm, memslot);
1014 }
1015 
kvm_stats_debugfs_mode(const struct _kvm_stats_desc * pdesc)1016 static umode_t kvm_stats_debugfs_mode(const struct _kvm_stats_desc *pdesc)
1017 {
1018 	switch (pdesc->desc.flags & KVM_STATS_TYPE_MASK) {
1019 	case KVM_STATS_TYPE_INSTANT:
1020 		return 0444;
1021 	case KVM_STATS_TYPE_CUMULATIVE:
1022 	case KVM_STATS_TYPE_PEAK:
1023 	default:
1024 		return 0644;
1025 	}
1026 }
1027 
1028 
kvm_destroy_vm_debugfs(struct kvm * kvm)1029 static void kvm_destroy_vm_debugfs(struct kvm *kvm)
1030 {
1031 	int i;
1032 	int kvm_debugfs_num_entries = kvm_vm_stats_header.num_desc +
1033 				      kvm_vcpu_stats_header.num_desc;
1034 
1035 	if (IS_ERR(kvm->debugfs_dentry))
1036 		return;
1037 
1038 	debugfs_remove_recursive(kvm->debugfs_dentry);
1039 
1040 	if (kvm->debugfs_stat_data) {
1041 		for (i = 0; i < kvm_debugfs_num_entries; i++)
1042 			kfree(kvm->debugfs_stat_data[i]);
1043 		kfree(kvm->debugfs_stat_data);
1044 	}
1045 }
1046 
kvm_create_vm_debugfs(struct kvm * kvm,const char * fdname)1047 static int kvm_create_vm_debugfs(struct kvm *kvm, const char *fdname)
1048 {
1049 	static DEFINE_MUTEX(kvm_debugfs_lock);
1050 	struct dentry *dent;
1051 	char dir_name[ITOA_MAX_LEN * 2];
1052 	struct kvm_stat_data *stat_data;
1053 	const struct _kvm_stats_desc *pdesc;
1054 	int i, ret = -ENOMEM;
1055 	int kvm_debugfs_num_entries = kvm_vm_stats_header.num_desc +
1056 				      kvm_vcpu_stats_header.num_desc;
1057 
1058 	if (!debugfs_initialized())
1059 		return 0;
1060 
1061 	snprintf(dir_name, sizeof(dir_name), "%d-%s", task_pid_nr(current), fdname);
1062 	mutex_lock(&kvm_debugfs_lock);
1063 	dent = debugfs_lookup(dir_name, kvm_debugfs_dir);
1064 	if (dent) {
1065 		pr_warn_ratelimited("KVM: debugfs: duplicate directory %s\n", dir_name);
1066 		dput(dent);
1067 		mutex_unlock(&kvm_debugfs_lock);
1068 		return 0;
1069 	}
1070 	dent = debugfs_create_dir(dir_name, kvm_debugfs_dir);
1071 	mutex_unlock(&kvm_debugfs_lock);
1072 	if (IS_ERR(dent))
1073 		return 0;
1074 
1075 	kvm->debugfs_dentry = dent;
1076 	kvm->debugfs_stat_data = kcalloc(kvm_debugfs_num_entries,
1077 					 sizeof(*kvm->debugfs_stat_data),
1078 					 GFP_KERNEL_ACCOUNT);
1079 	if (!kvm->debugfs_stat_data)
1080 		goto out_err;
1081 
1082 	for (i = 0; i < kvm_vm_stats_header.num_desc; ++i) {
1083 		pdesc = &kvm_vm_stats_desc[i];
1084 		stat_data = kzalloc(sizeof(*stat_data), GFP_KERNEL_ACCOUNT);
1085 		if (!stat_data)
1086 			goto out_err;
1087 
1088 		stat_data->kvm = kvm;
1089 		stat_data->desc = pdesc;
1090 		stat_data->kind = KVM_STAT_VM;
1091 		kvm->debugfs_stat_data[i] = stat_data;
1092 		debugfs_create_file(pdesc->name, kvm_stats_debugfs_mode(pdesc),
1093 				    kvm->debugfs_dentry, stat_data,
1094 				    &stat_fops_per_vm);
1095 	}
1096 
1097 	for (i = 0; i < kvm_vcpu_stats_header.num_desc; ++i) {
1098 		pdesc = &kvm_vcpu_stats_desc[i];
1099 		stat_data = kzalloc(sizeof(*stat_data), GFP_KERNEL_ACCOUNT);
1100 		if (!stat_data)
1101 			goto out_err;
1102 
1103 		stat_data->kvm = kvm;
1104 		stat_data->desc = pdesc;
1105 		stat_data->kind = KVM_STAT_VCPU;
1106 		kvm->debugfs_stat_data[i + kvm_vm_stats_header.num_desc] = stat_data;
1107 		debugfs_create_file(pdesc->name, kvm_stats_debugfs_mode(pdesc),
1108 				    kvm->debugfs_dentry, stat_data,
1109 				    &stat_fops_per_vm);
1110 	}
1111 
1112 	ret = kvm_arch_create_vm_debugfs(kvm);
1113 	if (ret)
1114 		goto out_err;
1115 
1116 	return 0;
1117 out_err:
1118 	kvm_destroy_vm_debugfs(kvm);
1119 	return ret;
1120 }
1121 
1122 /*
1123  * Called after the VM is otherwise initialized, but just before adding it to
1124  * the vm_list.
1125  */
kvm_arch_post_init_vm(struct kvm * kvm)1126 int __weak kvm_arch_post_init_vm(struct kvm *kvm)
1127 {
1128 	return 0;
1129 }
1130 
1131 /*
1132  * Called just after removing the VM from the vm_list, but before doing any
1133  * other destruction.
1134  */
kvm_arch_pre_destroy_vm(struct kvm * kvm)1135 void __weak kvm_arch_pre_destroy_vm(struct kvm *kvm)
1136 {
1137 }
1138 
1139 /*
1140  * Called after per-vm debugfs created.  When called kvm->debugfs_dentry should
1141  * be setup already, so we can create arch-specific debugfs entries under it.
1142  * Cleanup should be automatic done in kvm_destroy_vm_debugfs() recursively, so
1143  * a per-arch destroy interface is not needed.
1144  */
kvm_arch_create_vm_debugfs(struct kvm * kvm)1145 int __weak kvm_arch_create_vm_debugfs(struct kvm *kvm)
1146 {
1147 	return 0;
1148 }
1149 
kvm_create_vm(unsigned long type,const char * fdname)1150 static struct kvm *kvm_create_vm(unsigned long type, const char *fdname)
1151 {
1152 	struct kvm *kvm = kvm_arch_alloc_vm();
1153 	struct kvm_memslots *slots;
1154 	int r = -ENOMEM;
1155 	int i, j;
1156 
1157 	if (!kvm)
1158 		return ERR_PTR(-ENOMEM);
1159 
1160 	/* KVM is pinned via open("/dev/kvm"), the fd passed to this ioctl(). */
1161 	__module_get(kvm_chardev_ops.owner);
1162 
1163 	KVM_MMU_LOCK_INIT(kvm);
1164 	mmgrab(current->mm);
1165 	kvm->mm = current->mm;
1166 	kvm_eventfd_init(kvm);
1167 	mutex_init(&kvm->lock);
1168 	mutex_init(&kvm->irq_lock);
1169 	mutex_init(&kvm->slots_lock);
1170 	mutex_init(&kvm->slots_arch_lock);
1171 	spin_lock_init(&kvm->mn_invalidate_lock);
1172 	rcuwait_init(&kvm->mn_memslots_update_rcuwait);
1173 	xa_init(&kvm->vcpu_array);
1174 
1175 	INIT_LIST_HEAD(&kvm->gpc_list);
1176 	spin_lock_init(&kvm->gpc_lock);
1177 
1178 	INIT_LIST_HEAD(&kvm->devices);
1179 	kvm->max_vcpus = KVM_MAX_VCPUS;
1180 
1181 	BUILD_BUG_ON(KVM_MEM_SLOTS_NUM > SHRT_MAX);
1182 
1183 	/*
1184 	 * Force subsequent debugfs file creations to fail if the VM directory
1185 	 * is not created (by kvm_create_vm_debugfs()).
1186 	 */
1187 	kvm->debugfs_dentry = ERR_PTR(-ENOENT);
1188 
1189 	snprintf(kvm->stats_id, sizeof(kvm->stats_id), "kvm-%d",
1190 		 task_pid_nr(current));
1191 
1192 	if (init_srcu_struct(&kvm->srcu))
1193 		goto out_err_no_srcu;
1194 	if (init_srcu_struct(&kvm->irq_srcu))
1195 		goto out_err_no_irq_srcu;
1196 
1197 	refcount_set(&kvm->users_count, 1);
1198 	for (i = 0; i < KVM_ADDRESS_SPACE_NUM; i++) {
1199 		for (j = 0; j < 2; j++) {
1200 			slots = &kvm->__memslots[i][j];
1201 
1202 			atomic_long_set(&slots->last_used_slot, (unsigned long)NULL);
1203 			slots->hva_tree = RB_ROOT_CACHED;
1204 			slots->gfn_tree = RB_ROOT;
1205 			hash_init(slots->id_hash);
1206 			slots->node_idx = j;
1207 
1208 			/* Generations must be different for each address space. */
1209 			slots->generation = i;
1210 		}
1211 
1212 		rcu_assign_pointer(kvm->memslots[i], &kvm->__memslots[i][0]);
1213 	}
1214 
1215 	for (i = 0; i < KVM_NR_BUSES; i++) {
1216 		rcu_assign_pointer(kvm->buses[i],
1217 			kzalloc(sizeof(struct kvm_io_bus), GFP_KERNEL_ACCOUNT));
1218 		if (!kvm->buses[i])
1219 			goto out_err_no_arch_destroy_vm;
1220 	}
1221 
1222 	r = kvm_arch_init_vm(kvm, type);
1223 	if (r)
1224 		goto out_err_no_arch_destroy_vm;
1225 
1226 	r = hardware_enable_all();
1227 	if (r)
1228 		goto out_err_no_disable;
1229 
1230 #ifdef CONFIG_HAVE_KVM_IRQFD
1231 	INIT_HLIST_HEAD(&kvm->irq_ack_notifier_list);
1232 #endif
1233 
1234 	r = kvm_init_mmu_notifier(kvm);
1235 	if (r)
1236 		goto out_err_no_mmu_notifier;
1237 
1238 	r = kvm_coalesced_mmio_init(kvm);
1239 	if (r < 0)
1240 		goto out_no_coalesced_mmio;
1241 
1242 	r = kvm_create_vm_debugfs(kvm, fdname);
1243 	if (r)
1244 		goto out_err_no_debugfs;
1245 
1246 	r = kvm_arch_post_init_vm(kvm);
1247 	if (r)
1248 		goto out_err;
1249 
1250 	mutex_lock(&kvm_lock);
1251 	list_add(&kvm->vm_list, &vm_list);
1252 	mutex_unlock(&kvm_lock);
1253 
1254 	preempt_notifier_inc();
1255 	kvm_init_pm_notifier(kvm);
1256 
1257 	return kvm;
1258 
1259 out_err:
1260 	kvm_destroy_vm_debugfs(kvm);
1261 out_err_no_debugfs:
1262 	kvm_coalesced_mmio_free(kvm);
1263 out_no_coalesced_mmio:
1264 #if defined(CONFIG_MMU_NOTIFIER) && defined(KVM_ARCH_WANT_MMU_NOTIFIER)
1265 	if (kvm->mmu_notifier.ops)
1266 		mmu_notifier_unregister(&kvm->mmu_notifier, current->mm);
1267 #endif
1268 out_err_no_mmu_notifier:
1269 	hardware_disable_all();
1270 out_err_no_disable:
1271 	kvm_arch_destroy_vm(kvm);
1272 out_err_no_arch_destroy_vm:
1273 	WARN_ON_ONCE(!refcount_dec_and_test(&kvm->users_count));
1274 	for (i = 0; i < KVM_NR_BUSES; i++)
1275 		kfree(kvm_get_bus(kvm, i));
1276 	cleanup_srcu_struct(&kvm->irq_srcu);
1277 out_err_no_irq_srcu:
1278 	cleanup_srcu_struct(&kvm->srcu);
1279 out_err_no_srcu:
1280 	kvm_arch_free_vm(kvm);
1281 	mmdrop(current->mm);
1282 	module_put(kvm_chardev_ops.owner);
1283 	return ERR_PTR(r);
1284 }
1285 
kvm_destroy_devices(struct kvm * kvm)1286 static void kvm_destroy_devices(struct kvm *kvm)
1287 {
1288 	struct kvm_device *dev, *tmp;
1289 
1290 	/*
1291 	 * We do not need to take the kvm->lock here, because nobody else
1292 	 * has a reference to the struct kvm at this point and therefore
1293 	 * cannot access the devices list anyhow.
1294 	 */
1295 	list_for_each_entry_safe(dev, tmp, &kvm->devices, vm_node) {
1296 		list_del(&dev->vm_node);
1297 		dev->ops->destroy(dev);
1298 	}
1299 }
1300 
kvm_destroy_vm(struct kvm * kvm)1301 static void kvm_destroy_vm(struct kvm *kvm)
1302 {
1303 	int i;
1304 	struct mm_struct *mm = kvm->mm;
1305 
1306 	kvm_destroy_pm_notifier(kvm);
1307 	kvm_uevent_notify_change(KVM_EVENT_DESTROY_VM, kvm);
1308 	kvm_destroy_vm_debugfs(kvm);
1309 	kvm_arch_sync_events(kvm);
1310 	mutex_lock(&kvm_lock);
1311 	list_del(&kvm->vm_list);
1312 	mutex_unlock(&kvm_lock);
1313 	kvm_arch_pre_destroy_vm(kvm);
1314 
1315 	kvm_free_irq_routing(kvm);
1316 	for (i = 0; i < KVM_NR_BUSES; i++) {
1317 		struct kvm_io_bus *bus = kvm_get_bus(kvm, i);
1318 
1319 		if (bus)
1320 			kvm_io_bus_destroy(bus);
1321 		kvm->buses[i] = NULL;
1322 	}
1323 	kvm_coalesced_mmio_free(kvm);
1324 #if defined(CONFIG_MMU_NOTIFIER) && defined(KVM_ARCH_WANT_MMU_NOTIFIER)
1325 	mmu_notifier_unregister(&kvm->mmu_notifier, kvm->mm);
1326 	/*
1327 	 * At this point, pending calls to invalidate_range_start()
1328 	 * have completed but no more MMU notifiers will run, so
1329 	 * mn_active_invalidate_count may remain unbalanced.
1330 	 * No threads can be waiting in kvm_swap_active_memslots() as the
1331 	 * last reference on KVM has been dropped, but freeing
1332 	 * memslots would deadlock without this manual intervention.
1333 	 */
1334 	WARN_ON(rcuwait_active(&kvm->mn_memslots_update_rcuwait));
1335 	kvm->mn_active_invalidate_count = 0;
1336 #else
1337 	kvm_flush_shadow_all(kvm);
1338 #endif
1339 	kvm_arch_destroy_vm(kvm);
1340 	kvm_destroy_devices(kvm);
1341 	for (i = 0; i < KVM_ADDRESS_SPACE_NUM; i++) {
1342 		kvm_free_memslots(kvm, &kvm->__memslots[i][0]);
1343 		kvm_free_memslots(kvm, &kvm->__memslots[i][1]);
1344 	}
1345 	cleanup_srcu_struct(&kvm->irq_srcu);
1346 	cleanup_srcu_struct(&kvm->srcu);
1347 	kvm_arch_free_vm(kvm);
1348 	preempt_notifier_dec();
1349 	hardware_disable_all();
1350 	mmdrop(mm);
1351 	module_put(kvm_chardev_ops.owner);
1352 }
1353 
kvm_get_kvm(struct kvm * kvm)1354 void kvm_get_kvm(struct kvm *kvm)
1355 {
1356 	refcount_inc(&kvm->users_count);
1357 }
1358 EXPORT_SYMBOL_GPL(kvm_get_kvm);
1359 
1360 /*
1361  * Make sure the vm is not during destruction, which is a safe version of
1362  * kvm_get_kvm().  Return true if kvm referenced successfully, false otherwise.
1363  */
kvm_get_kvm_safe(struct kvm * kvm)1364 bool kvm_get_kvm_safe(struct kvm *kvm)
1365 {
1366 	return refcount_inc_not_zero(&kvm->users_count);
1367 }
1368 EXPORT_SYMBOL_GPL(kvm_get_kvm_safe);
1369 
kvm_put_kvm(struct kvm * kvm)1370 void kvm_put_kvm(struct kvm *kvm)
1371 {
1372 	if (refcount_dec_and_test(&kvm->users_count))
1373 		kvm_destroy_vm(kvm);
1374 }
1375 EXPORT_SYMBOL_GPL(kvm_put_kvm);
1376 
1377 /*
1378  * Used to put a reference that was taken on behalf of an object associated
1379  * with a user-visible file descriptor, e.g. a vcpu or device, if installation
1380  * of the new file descriptor fails and the reference cannot be transferred to
1381  * its final owner.  In such cases, the caller is still actively using @kvm and
1382  * will fail miserably if the refcount unexpectedly hits zero.
1383  */
kvm_put_kvm_no_destroy(struct kvm * kvm)1384 void kvm_put_kvm_no_destroy(struct kvm *kvm)
1385 {
1386 	WARN_ON(refcount_dec_and_test(&kvm->users_count));
1387 }
1388 EXPORT_SYMBOL_GPL(kvm_put_kvm_no_destroy);
1389 
kvm_vm_release(struct inode * inode,struct file * filp)1390 static int kvm_vm_release(struct inode *inode, struct file *filp)
1391 {
1392 	struct kvm *kvm = filp->private_data;
1393 
1394 	kvm_irqfd_release(kvm);
1395 
1396 	kvm_put_kvm(kvm);
1397 	return 0;
1398 }
1399 
1400 /*
1401  * Allocation size is twice as large as the actual dirty bitmap size.
1402  * See kvm_vm_ioctl_get_dirty_log() why this is needed.
1403  */
kvm_alloc_dirty_bitmap(struct kvm_memory_slot * memslot)1404 static int kvm_alloc_dirty_bitmap(struct kvm_memory_slot *memslot)
1405 {
1406 	unsigned long dirty_bytes = kvm_dirty_bitmap_bytes(memslot);
1407 
1408 	memslot->dirty_bitmap = __vcalloc(2, dirty_bytes, GFP_KERNEL_ACCOUNT);
1409 	if (!memslot->dirty_bitmap)
1410 		return -ENOMEM;
1411 
1412 	return 0;
1413 }
1414 
kvm_get_inactive_memslots(struct kvm * kvm,int as_id)1415 static struct kvm_memslots *kvm_get_inactive_memslots(struct kvm *kvm, int as_id)
1416 {
1417 	struct kvm_memslots *active = __kvm_memslots(kvm, as_id);
1418 	int node_idx_inactive = active->node_idx ^ 1;
1419 
1420 	return &kvm->__memslots[as_id][node_idx_inactive];
1421 }
1422 
1423 /*
1424  * Helper to get the address space ID when one of memslot pointers may be NULL.
1425  * This also serves as a sanity that at least one of the pointers is non-NULL,
1426  * and that their address space IDs don't diverge.
1427  */
kvm_memslots_get_as_id(struct kvm_memory_slot * a,struct kvm_memory_slot * b)1428 static int kvm_memslots_get_as_id(struct kvm_memory_slot *a,
1429 				  struct kvm_memory_slot *b)
1430 {
1431 	if (WARN_ON_ONCE(!a && !b))
1432 		return 0;
1433 
1434 	if (!a)
1435 		return b->as_id;
1436 	if (!b)
1437 		return a->as_id;
1438 
1439 	WARN_ON_ONCE(a->as_id != b->as_id);
1440 	return a->as_id;
1441 }
1442 
kvm_insert_gfn_node(struct kvm_memslots * slots,struct kvm_memory_slot * slot)1443 static void kvm_insert_gfn_node(struct kvm_memslots *slots,
1444 				struct kvm_memory_slot *slot)
1445 {
1446 	struct rb_root *gfn_tree = &slots->gfn_tree;
1447 	struct rb_node **node, *parent;
1448 	int idx = slots->node_idx;
1449 
1450 	parent = NULL;
1451 	for (node = &gfn_tree->rb_node; *node; ) {
1452 		struct kvm_memory_slot *tmp;
1453 
1454 		tmp = container_of(*node, struct kvm_memory_slot, gfn_node[idx]);
1455 		parent = *node;
1456 		if (slot->base_gfn < tmp->base_gfn)
1457 			node = &(*node)->rb_left;
1458 		else if (slot->base_gfn > tmp->base_gfn)
1459 			node = &(*node)->rb_right;
1460 		else
1461 			BUG();
1462 	}
1463 
1464 	rb_link_node(&slot->gfn_node[idx], parent, node);
1465 	rb_insert_color(&slot->gfn_node[idx], gfn_tree);
1466 }
1467 
kvm_erase_gfn_node(struct kvm_memslots * slots,struct kvm_memory_slot * slot)1468 static void kvm_erase_gfn_node(struct kvm_memslots *slots,
1469 			       struct kvm_memory_slot *slot)
1470 {
1471 	rb_erase(&slot->gfn_node[slots->node_idx], &slots->gfn_tree);
1472 }
1473 
kvm_replace_gfn_node(struct kvm_memslots * slots,struct kvm_memory_slot * old,struct kvm_memory_slot * new)1474 static void kvm_replace_gfn_node(struct kvm_memslots *slots,
1475 				 struct kvm_memory_slot *old,
1476 				 struct kvm_memory_slot *new)
1477 {
1478 	int idx = slots->node_idx;
1479 
1480 	WARN_ON_ONCE(old->base_gfn != new->base_gfn);
1481 
1482 	rb_replace_node(&old->gfn_node[idx], &new->gfn_node[idx],
1483 			&slots->gfn_tree);
1484 }
1485 
1486 /*
1487  * Replace @old with @new in the inactive memslots.
1488  *
1489  * With NULL @old this simply adds @new.
1490  * With NULL @new this simply removes @old.
1491  *
1492  * If @new is non-NULL its hva_node[slots_idx] range has to be set
1493  * appropriately.
1494  */
kvm_replace_memslot(struct kvm * kvm,struct kvm_memory_slot * old,struct kvm_memory_slot * new)1495 static void kvm_replace_memslot(struct kvm *kvm,
1496 				struct kvm_memory_slot *old,
1497 				struct kvm_memory_slot *new)
1498 {
1499 	int as_id = kvm_memslots_get_as_id(old, new);
1500 	struct kvm_memslots *slots = kvm_get_inactive_memslots(kvm, as_id);
1501 	int idx = slots->node_idx;
1502 
1503 	if (old) {
1504 		hash_del(&old->id_node[idx]);
1505 		interval_tree_remove(&old->hva_node[idx], &slots->hva_tree);
1506 
1507 		if ((long)old == atomic_long_read(&slots->last_used_slot))
1508 			atomic_long_set(&slots->last_used_slot, (long)new);
1509 
1510 		if (!new) {
1511 			kvm_erase_gfn_node(slots, old);
1512 			return;
1513 		}
1514 	}
1515 
1516 	/*
1517 	 * Initialize @new's hva range.  Do this even when replacing an @old
1518 	 * slot, kvm_copy_memslot() deliberately does not touch node data.
1519 	 */
1520 	new->hva_node[idx].start = new->userspace_addr;
1521 	new->hva_node[idx].last = new->userspace_addr +
1522 				  (new->npages << PAGE_SHIFT) - 1;
1523 
1524 	/*
1525 	 * (Re)Add the new memslot.  There is no O(1) interval_tree_replace(),
1526 	 * hva_node needs to be swapped with remove+insert even though hva can't
1527 	 * change when replacing an existing slot.
1528 	 */
1529 	hash_add(slots->id_hash, &new->id_node[idx], new->id);
1530 	interval_tree_insert(&new->hva_node[idx], &slots->hva_tree);
1531 
1532 	/*
1533 	 * If the memslot gfn is unchanged, rb_replace_node() can be used to
1534 	 * switch the node in the gfn tree instead of removing the old and
1535 	 * inserting the new as two separate operations. Replacement is a
1536 	 * single O(1) operation versus two O(log(n)) operations for
1537 	 * remove+insert.
1538 	 */
1539 	if (old && old->base_gfn == new->base_gfn) {
1540 		kvm_replace_gfn_node(slots, old, new);
1541 	} else {
1542 		if (old)
1543 			kvm_erase_gfn_node(slots, old);
1544 		kvm_insert_gfn_node(slots, new);
1545 	}
1546 }
1547 
check_memory_region_flags(const struct kvm_userspace_memory_region * mem)1548 static int check_memory_region_flags(const struct kvm_userspace_memory_region *mem)
1549 {
1550 	u32 valid_flags = KVM_MEM_LOG_DIRTY_PAGES;
1551 
1552 #ifdef __KVM_HAVE_READONLY_MEM
1553 	valid_flags |= KVM_MEM_READONLY;
1554 #endif
1555 
1556 	if (mem->flags & ~valid_flags)
1557 		return -EINVAL;
1558 
1559 	return 0;
1560 }
1561 
kvm_swap_active_memslots(struct kvm * kvm,int as_id)1562 static void kvm_swap_active_memslots(struct kvm *kvm, int as_id)
1563 {
1564 	struct kvm_memslots *slots = kvm_get_inactive_memslots(kvm, as_id);
1565 
1566 	/* Grab the generation from the activate memslots. */
1567 	u64 gen = __kvm_memslots(kvm, as_id)->generation;
1568 
1569 	WARN_ON(gen & KVM_MEMSLOT_GEN_UPDATE_IN_PROGRESS);
1570 	slots->generation = gen | KVM_MEMSLOT_GEN_UPDATE_IN_PROGRESS;
1571 
1572 	/*
1573 	 * Do not store the new memslots while there are invalidations in
1574 	 * progress, otherwise the locking in invalidate_range_start and
1575 	 * invalidate_range_end will be unbalanced.
1576 	 */
1577 	spin_lock(&kvm->mn_invalidate_lock);
1578 	prepare_to_rcuwait(&kvm->mn_memslots_update_rcuwait);
1579 	while (kvm->mn_active_invalidate_count) {
1580 		set_current_state(TASK_UNINTERRUPTIBLE);
1581 		spin_unlock(&kvm->mn_invalidate_lock);
1582 		schedule();
1583 		spin_lock(&kvm->mn_invalidate_lock);
1584 	}
1585 	finish_rcuwait(&kvm->mn_memslots_update_rcuwait);
1586 	rcu_assign_pointer(kvm->memslots[as_id], slots);
1587 	spin_unlock(&kvm->mn_invalidate_lock);
1588 
1589 	/*
1590 	 * Acquired in kvm_set_memslot. Must be released before synchronize
1591 	 * SRCU below in order to avoid deadlock with another thread
1592 	 * acquiring the slots_arch_lock in an srcu critical section.
1593 	 */
1594 	mutex_unlock(&kvm->slots_arch_lock);
1595 
1596 	synchronize_srcu_expedited(&kvm->srcu);
1597 
1598 	/*
1599 	 * Increment the new memslot generation a second time, dropping the
1600 	 * update in-progress flag and incrementing the generation based on
1601 	 * the number of address spaces.  This provides a unique and easily
1602 	 * identifiable generation number while the memslots are in flux.
1603 	 */
1604 	gen = slots->generation & ~KVM_MEMSLOT_GEN_UPDATE_IN_PROGRESS;
1605 
1606 	/*
1607 	 * Generations must be unique even across address spaces.  We do not need
1608 	 * a global counter for that, instead the generation space is evenly split
1609 	 * across address spaces.  For example, with two address spaces, address
1610 	 * space 0 will use generations 0, 2, 4, ... while address space 1 will
1611 	 * use generations 1, 3, 5, ...
1612 	 */
1613 	gen += KVM_ADDRESS_SPACE_NUM;
1614 
1615 	kvm_arch_memslots_updated(kvm, gen);
1616 
1617 	slots->generation = gen;
1618 }
1619 
kvm_prepare_memory_region(struct kvm * kvm,const struct kvm_memory_slot * old,struct kvm_memory_slot * new,enum kvm_mr_change change)1620 static int kvm_prepare_memory_region(struct kvm *kvm,
1621 				     const struct kvm_memory_slot *old,
1622 				     struct kvm_memory_slot *new,
1623 				     enum kvm_mr_change change)
1624 {
1625 	int r;
1626 
1627 	/*
1628 	 * If dirty logging is disabled, nullify the bitmap; the old bitmap
1629 	 * will be freed on "commit".  If logging is enabled in both old and
1630 	 * new, reuse the existing bitmap.  If logging is enabled only in the
1631 	 * new and KVM isn't using a ring buffer, allocate and initialize a
1632 	 * new bitmap.
1633 	 */
1634 	if (change != KVM_MR_DELETE) {
1635 		if (!(new->flags & KVM_MEM_LOG_DIRTY_PAGES))
1636 			new->dirty_bitmap = NULL;
1637 		else if (old && old->dirty_bitmap)
1638 			new->dirty_bitmap = old->dirty_bitmap;
1639 		else if (kvm_use_dirty_bitmap(kvm)) {
1640 			r = kvm_alloc_dirty_bitmap(new);
1641 			if (r)
1642 				return r;
1643 
1644 			if (kvm_dirty_log_manual_protect_and_init_set(kvm))
1645 				bitmap_set(new->dirty_bitmap, 0, new->npages);
1646 		}
1647 	}
1648 
1649 	r = kvm_arch_prepare_memory_region(kvm, old, new, change);
1650 
1651 	/* Free the bitmap on failure if it was allocated above. */
1652 	if (r && new && new->dirty_bitmap && (!old || !old->dirty_bitmap))
1653 		kvm_destroy_dirty_bitmap(new);
1654 
1655 	return r;
1656 }
1657 
kvm_commit_memory_region(struct kvm * kvm,struct kvm_memory_slot * old,const struct kvm_memory_slot * new,enum kvm_mr_change change)1658 static void kvm_commit_memory_region(struct kvm *kvm,
1659 				     struct kvm_memory_slot *old,
1660 				     const struct kvm_memory_slot *new,
1661 				     enum kvm_mr_change change)
1662 {
1663 	int old_flags = old ? old->flags : 0;
1664 	int new_flags = new ? new->flags : 0;
1665 	/*
1666 	 * Update the total number of memslot pages before calling the arch
1667 	 * hook so that architectures can consume the result directly.
1668 	 */
1669 	if (change == KVM_MR_DELETE)
1670 		kvm->nr_memslot_pages -= old->npages;
1671 	else if (change == KVM_MR_CREATE)
1672 		kvm->nr_memslot_pages += new->npages;
1673 
1674 	if ((old_flags ^ new_flags) & KVM_MEM_LOG_DIRTY_PAGES) {
1675 		int change = (new_flags & KVM_MEM_LOG_DIRTY_PAGES) ? 1 : -1;
1676 		atomic_set(&kvm->nr_memslots_dirty_logging,
1677 			   atomic_read(&kvm->nr_memslots_dirty_logging) + change);
1678 	}
1679 
1680 	kvm_arch_commit_memory_region(kvm, old, new, change);
1681 
1682 	switch (change) {
1683 	case KVM_MR_CREATE:
1684 		/* Nothing more to do. */
1685 		break;
1686 	case KVM_MR_DELETE:
1687 		/* Free the old memslot and all its metadata. */
1688 		kvm_free_memslot(kvm, old);
1689 		break;
1690 	case KVM_MR_MOVE:
1691 	case KVM_MR_FLAGS_ONLY:
1692 		/*
1693 		 * Free the dirty bitmap as needed; the below check encompasses
1694 		 * both the flags and whether a ring buffer is being used)
1695 		 */
1696 		if (old->dirty_bitmap && !new->dirty_bitmap)
1697 			kvm_destroy_dirty_bitmap(old);
1698 
1699 		/*
1700 		 * The final quirk.  Free the detached, old slot, but only its
1701 		 * memory, not any metadata.  Metadata, including arch specific
1702 		 * data, may be reused by @new.
1703 		 */
1704 		kfree(old);
1705 		break;
1706 	default:
1707 		BUG();
1708 	}
1709 }
1710 
1711 /*
1712  * Activate @new, which must be installed in the inactive slots by the caller,
1713  * by swapping the active slots and then propagating @new to @old once @old is
1714  * unreachable and can be safely modified.
1715  *
1716  * With NULL @old this simply adds @new to @active (while swapping the sets).
1717  * With NULL @new this simply removes @old from @active and frees it
1718  * (while also swapping the sets).
1719  */
kvm_activate_memslot(struct kvm * kvm,struct kvm_memory_slot * old,struct kvm_memory_slot * new)1720 static void kvm_activate_memslot(struct kvm *kvm,
1721 				 struct kvm_memory_slot *old,
1722 				 struct kvm_memory_slot *new)
1723 {
1724 	int as_id = kvm_memslots_get_as_id(old, new);
1725 
1726 	kvm_swap_active_memslots(kvm, as_id);
1727 
1728 	/* Propagate the new memslot to the now inactive memslots. */
1729 	kvm_replace_memslot(kvm, old, new);
1730 }
1731 
kvm_copy_memslot(struct kvm_memory_slot * dest,const struct kvm_memory_slot * src)1732 static void kvm_copy_memslot(struct kvm_memory_slot *dest,
1733 			     const struct kvm_memory_slot *src)
1734 {
1735 	dest->base_gfn = src->base_gfn;
1736 	dest->npages = src->npages;
1737 	dest->dirty_bitmap = src->dirty_bitmap;
1738 	dest->arch = src->arch;
1739 	dest->userspace_addr = src->userspace_addr;
1740 	dest->flags = src->flags;
1741 	dest->id = src->id;
1742 	dest->as_id = src->as_id;
1743 }
1744 
kvm_invalidate_memslot(struct kvm * kvm,struct kvm_memory_slot * old,struct kvm_memory_slot * invalid_slot)1745 static void kvm_invalidate_memslot(struct kvm *kvm,
1746 				   struct kvm_memory_slot *old,
1747 				   struct kvm_memory_slot *invalid_slot)
1748 {
1749 	/*
1750 	 * Mark the current slot INVALID.  As with all memslot modifications,
1751 	 * this must be done on an unreachable slot to avoid modifying the
1752 	 * current slot in the active tree.
1753 	 */
1754 	kvm_copy_memslot(invalid_slot, old);
1755 	invalid_slot->flags |= KVM_MEMSLOT_INVALID;
1756 	kvm_replace_memslot(kvm, old, invalid_slot);
1757 
1758 	/*
1759 	 * Activate the slot that is now marked INVALID, but don't propagate
1760 	 * the slot to the now inactive slots. The slot is either going to be
1761 	 * deleted or recreated as a new slot.
1762 	 */
1763 	kvm_swap_active_memslots(kvm, old->as_id);
1764 
1765 	/*
1766 	 * From this point no new shadow pages pointing to a deleted, or moved,
1767 	 * memslot will be created.  Validation of sp->gfn happens in:
1768 	 *	- gfn_to_hva (kvm_read_guest, gfn_to_pfn)
1769 	 *	- kvm_is_visible_gfn (mmu_check_root)
1770 	 */
1771 	kvm_arch_flush_shadow_memslot(kvm, old);
1772 	kvm_arch_guest_memory_reclaimed(kvm);
1773 
1774 	/* Was released by kvm_swap_active_memslots(), reacquire. */
1775 	mutex_lock(&kvm->slots_arch_lock);
1776 
1777 	/*
1778 	 * Copy the arch-specific field of the newly-installed slot back to the
1779 	 * old slot as the arch data could have changed between releasing
1780 	 * slots_arch_lock in kvm_swap_active_memslots() and re-acquiring the lock
1781 	 * above.  Writers are required to retrieve memslots *after* acquiring
1782 	 * slots_arch_lock, thus the active slot's data is guaranteed to be fresh.
1783 	 */
1784 	old->arch = invalid_slot->arch;
1785 }
1786 
kvm_create_memslot(struct kvm * kvm,struct kvm_memory_slot * new)1787 static void kvm_create_memslot(struct kvm *kvm,
1788 			       struct kvm_memory_slot *new)
1789 {
1790 	/* Add the new memslot to the inactive set and activate. */
1791 	kvm_replace_memslot(kvm, NULL, new);
1792 	kvm_activate_memslot(kvm, NULL, new);
1793 }
1794 
kvm_delete_memslot(struct kvm * kvm,struct kvm_memory_slot * old,struct kvm_memory_slot * invalid_slot)1795 static void kvm_delete_memslot(struct kvm *kvm,
1796 			       struct kvm_memory_slot *old,
1797 			       struct kvm_memory_slot *invalid_slot)
1798 {
1799 	/*
1800 	 * Remove the old memslot (in the inactive memslots) by passing NULL as
1801 	 * the "new" slot, and for the invalid version in the active slots.
1802 	 */
1803 	kvm_replace_memslot(kvm, old, NULL);
1804 	kvm_activate_memslot(kvm, invalid_slot, NULL);
1805 }
1806 
kvm_move_memslot(struct kvm * kvm,struct kvm_memory_slot * old,struct kvm_memory_slot * new,struct kvm_memory_slot * invalid_slot)1807 static void kvm_move_memslot(struct kvm *kvm,
1808 			     struct kvm_memory_slot *old,
1809 			     struct kvm_memory_slot *new,
1810 			     struct kvm_memory_slot *invalid_slot)
1811 {
1812 	/*
1813 	 * Replace the old memslot in the inactive slots, and then swap slots
1814 	 * and replace the current INVALID with the new as well.
1815 	 */
1816 	kvm_replace_memslot(kvm, old, new);
1817 	kvm_activate_memslot(kvm, invalid_slot, new);
1818 }
1819 
kvm_update_flags_memslot(struct kvm * kvm,struct kvm_memory_slot * old,struct kvm_memory_slot * new)1820 static void kvm_update_flags_memslot(struct kvm *kvm,
1821 				     struct kvm_memory_slot *old,
1822 				     struct kvm_memory_slot *new)
1823 {
1824 	/*
1825 	 * Similar to the MOVE case, but the slot doesn't need to be zapped as
1826 	 * an intermediate step. Instead, the old memslot is simply replaced
1827 	 * with a new, updated copy in both memslot sets.
1828 	 */
1829 	kvm_replace_memslot(kvm, old, new);
1830 	kvm_activate_memslot(kvm, old, new);
1831 }
1832 
kvm_set_memslot(struct kvm * kvm,struct kvm_memory_slot * old,struct kvm_memory_slot * new,enum kvm_mr_change change)1833 static int kvm_set_memslot(struct kvm *kvm,
1834 			   struct kvm_memory_slot *old,
1835 			   struct kvm_memory_slot *new,
1836 			   enum kvm_mr_change change)
1837 {
1838 	struct kvm_memory_slot *invalid_slot;
1839 	int r;
1840 
1841 	/*
1842 	 * Released in kvm_swap_active_memslots().
1843 	 *
1844 	 * Must be held from before the current memslots are copied until after
1845 	 * the new memslots are installed with rcu_assign_pointer, then
1846 	 * released before the synchronize srcu in kvm_swap_active_memslots().
1847 	 *
1848 	 * When modifying memslots outside of the slots_lock, must be held
1849 	 * before reading the pointer to the current memslots until after all
1850 	 * changes to those memslots are complete.
1851 	 *
1852 	 * These rules ensure that installing new memslots does not lose
1853 	 * changes made to the previous memslots.
1854 	 */
1855 	mutex_lock(&kvm->slots_arch_lock);
1856 
1857 	/*
1858 	 * Invalidate the old slot if it's being deleted or moved.  This is
1859 	 * done prior to actually deleting/moving the memslot to allow vCPUs to
1860 	 * continue running by ensuring there are no mappings or shadow pages
1861 	 * for the memslot when it is deleted/moved.  Without pre-invalidation
1862 	 * (and without a lock), a window would exist between effecting the
1863 	 * delete/move and committing the changes in arch code where KVM or a
1864 	 * guest could access a non-existent memslot.
1865 	 *
1866 	 * Modifications are done on a temporary, unreachable slot.  The old
1867 	 * slot needs to be preserved in case a later step fails and the
1868 	 * invalidation needs to be reverted.
1869 	 */
1870 	if (change == KVM_MR_DELETE || change == KVM_MR_MOVE) {
1871 		invalid_slot = kzalloc(sizeof(*invalid_slot), GFP_KERNEL_ACCOUNT);
1872 		if (!invalid_slot) {
1873 			mutex_unlock(&kvm->slots_arch_lock);
1874 			return -ENOMEM;
1875 		}
1876 		kvm_invalidate_memslot(kvm, old, invalid_slot);
1877 	}
1878 
1879 	r = kvm_prepare_memory_region(kvm, old, new, change);
1880 	if (r) {
1881 		/*
1882 		 * For DELETE/MOVE, revert the above INVALID change.  No
1883 		 * modifications required since the original slot was preserved
1884 		 * in the inactive slots.  Changing the active memslots also
1885 		 * release slots_arch_lock.
1886 		 */
1887 		if (change == KVM_MR_DELETE || change == KVM_MR_MOVE) {
1888 			kvm_activate_memslot(kvm, invalid_slot, old);
1889 			kfree(invalid_slot);
1890 		} else {
1891 			mutex_unlock(&kvm->slots_arch_lock);
1892 		}
1893 		return r;
1894 	}
1895 
1896 	/*
1897 	 * For DELETE and MOVE, the working slot is now active as the INVALID
1898 	 * version of the old slot.  MOVE is particularly special as it reuses
1899 	 * the old slot and returns a copy of the old slot (in working_slot).
1900 	 * For CREATE, there is no old slot.  For DELETE and FLAGS_ONLY, the
1901 	 * old slot is detached but otherwise preserved.
1902 	 */
1903 	if (change == KVM_MR_CREATE)
1904 		kvm_create_memslot(kvm, new);
1905 	else if (change == KVM_MR_DELETE)
1906 		kvm_delete_memslot(kvm, old, invalid_slot);
1907 	else if (change == KVM_MR_MOVE)
1908 		kvm_move_memslot(kvm, old, new, invalid_slot);
1909 	else if (change == KVM_MR_FLAGS_ONLY)
1910 		kvm_update_flags_memslot(kvm, old, new);
1911 	else
1912 		BUG();
1913 
1914 	/* Free the temporary INVALID slot used for DELETE and MOVE. */
1915 	if (change == KVM_MR_DELETE || change == KVM_MR_MOVE)
1916 		kfree(invalid_slot);
1917 
1918 	/*
1919 	 * No need to refresh new->arch, changes after dropping slots_arch_lock
1920 	 * will directly hit the final, active memslot.  Architectures are
1921 	 * responsible for knowing that new->arch may be stale.
1922 	 */
1923 	kvm_commit_memory_region(kvm, old, new, change);
1924 
1925 	return 0;
1926 }
1927 
kvm_check_memslot_overlap(struct kvm_memslots * slots,int id,gfn_t start,gfn_t end)1928 static bool kvm_check_memslot_overlap(struct kvm_memslots *slots, int id,
1929 				      gfn_t start, gfn_t end)
1930 {
1931 	struct kvm_memslot_iter iter;
1932 
1933 	kvm_for_each_memslot_in_gfn_range(&iter, slots, start, end) {
1934 		if (iter.slot->id != id)
1935 			return true;
1936 	}
1937 
1938 	return false;
1939 }
1940 
1941 /*
1942  * Allocate some memory and give it an address in the guest physical address
1943  * space.
1944  *
1945  * Discontiguous memory is allowed, mostly for framebuffers.
1946  *
1947  * Must be called holding kvm->slots_lock for write.
1948  */
__kvm_set_memory_region(struct kvm * kvm,const struct kvm_userspace_memory_region * mem)1949 int __kvm_set_memory_region(struct kvm *kvm,
1950 			    const struct kvm_userspace_memory_region *mem)
1951 {
1952 	struct kvm_memory_slot *old, *new;
1953 	struct kvm_memslots *slots;
1954 	enum kvm_mr_change change;
1955 	unsigned long npages;
1956 	gfn_t base_gfn;
1957 	int as_id, id;
1958 	int r;
1959 
1960 	r = check_memory_region_flags(mem);
1961 	if (r)
1962 		return r;
1963 
1964 	as_id = mem->slot >> 16;
1965 	id = (u16)mem->slot;
1966 
1967 	/* General sanity checks */
1968 	if ((mem->memory_size & (PAGE_SIZE - 1)) ||
1969 	    (mem->memory_size != (unsigned long)mem->memory_size))
1970 		return -EINVAL;
1971 	if (mem->guest_phys_addr & (PAGE_SIZE - 1))
1972 		return -EINVAL;
1973 	/* We can read the guest memory with __xxx_user() later on. */
1974 	if ((mem->userspace_addr & (PAGE_SIZE - 1)) ||
1975 	    (mem->userspace_addr != untagged_addr(mem->userspace_addr)) ||
1976 	     !access_ok((void __user *)(unsigned long)mem->userspace_addr,
1977 			mem->memory_size))
1978 		return -EINVAL;
1979 	if (as_id >= KVM_ADDRESS_SPACE_NUM || id >= KVM_MEM_SLOTS_NUM)
1980 		return -EINVAL;
1981 	if (mem->guest_phys_addr + mem->memory_size < mem->guest_phys_addr)
1982 		return -EINVAL;
1983 	if ((mem->memory_size >> PAGE_SHIFT) > KVM_MEM_MAX_NR_PAGES)
1984 		return -EINVAL;
1985 
1986 	slots = __kvm_memslots(kvm, as_id);
1987 
1988 	/*
1989 	 * Note, the old memslot (and the pointer itself!) may be invalidated
1990 	 * and/or destroyed by kvm_set_memslot().
1991 	 */
1992 	old = id_to_memslot(slots, id);
1993 
1994 	if (!mem->memory_size) {
1995 		if (!old || !old->npages)
1996 			return -EINVAL;
1997 
1998 		if (WARN_ON_ONCE(kvm->nr_memslot_pages < old->npages))
1999 			return -EIO;
2000 
2001 		return kvm_set_memslot(kvm, old, NULL, KVM_MR_DELETE);
2002 	}
2003 
2004 	base_gfn = (mem->guest_phys_addr >> PAGE_SHIFT);
2005 	npages = (mem->memory_size >> PAGE_SHIFT);
2006 
2007 	if (!old || !old->npages) {
2008 		change = KVM_MR_CREATE;
2009 
2010 		/*
2011 		 * To simplify KVM internals, the total number of pages across
2012 		 * all memslots must fit in an unsigned long.
2013 		 */
2014 		if ((kvm->nr_memslot_pages + npages) < kvm->nr_memslot_pages)
2015 			return -EINVAL;
2016 	} else { /* Modify an existing slot. */
2017 		if ((mem->userspace_addr != old->userspace_addr) ||
2018 		    (npages != old->npages) ||
2019 		    ((mem->flags ^ old->flags) & KVM_MEM_READONLY))
2020 			return -EINVAL;
2021 
2022 		if (base_gfn != old->base_gfn)
2023 			change = KVM_MR_MOVE;
2024 		else if (mem->flags != old->flags)
2025 			change = KVM_MR_FLAGS_ONLY;
2026 		else /* Nothing to change. */
2027 			return 0;
2028 	}
2029 
2030 	if ((change == KVM_MR_CREATE || change == KVM_MR_MOVE) &&
2031 	    kvm_check_memslot_overlap(slots, id, base_gfn, base_gfn + npages))
2032 		return -EEXIST;
2033 
2034 	/* Allocate a slot that will persist in the memslot. */
2035 	new = kzalloc(sizeof(*new), GFP_KERNEL_ACCOUNT);
2036 	if (!new)
2037 		return -ENOMEM;
2038 
2039 	new->as_id = as_id;
2040 	new->id = id;
2041 	new->base_gfn = base_gfn;
2042 	new->npages = npages;
2043 	new->flags = mem->flags;
2044 	new->userspace_addr = mem->userspace_addr;
2045 
2046 	r = kvm_set_memslot(kvm, old, new, change);
2047 	if (r)
2048 		kfree(new);
2049 	return r;
2050 }
2051 EXPORT_SYMBOL_GPL(__kvm_set_memory_region);
2052 
kvm_set_memory_region(struct kvm * kvm,const struct kvm_userspace_memory_region * mem)2053 int kvm_set_memory_region(struct kvm *kvm,
2054 			  const struct kvm_userspace_memory_region *mem)
2055 {
2056 	int r;
2057 
2058 	mutex_lock(&kvm->slots_lock);
2059 	r = __kvm_set_memory_region(kvm, mem);
2060 	mutex_unlock(&kvm->slots_lock);
2061 	return r;
2062 }
2063 EXPORT_SYMBOL_GPL(kvm_set_memory_region);
2064 
kvm_vm_ioctl_set_memory_region(struct kvm * kvm,struct kvm_userspace_memory_region * mem)2065 static int kvm_vm_ioctl_set_memory_region(struct kvm *kvm,
2066 					  struct kvm_userspace_memory_region *mem)
2067 {
2068 	if ((u16)mem->slot >= KVM_USER_MEM_SLOTS)
2069 		return -EINVAL;
2070 
2071 	return kvm_set_memory_region(kvm, mem);
2072 }
2073 
2074 #ifndef CONFIG_KVM_GENERIC_DIRTYLOG_READ_PROTECT
2075 /**
2076  * kvm_get_dirty_log - get a snapshot of dirty pages
2077  * @kvm:	pointer to kvm instance
2078  * @log:	slot id and address to which we copy the log
2079  * @is_dirty:	set to '1' if any dirty pages were found
2080  * @memslot:	set to the associated memslot, always valid on success
2081  */
kvm_get_dirty_log(struct kvm * kvm,struct kvm_dirty_log * log,int * is_dirty,struct kvm_memory_slot ** memslot)2082 int kvm_get_dirty_log(struct kvm *kvm, struct kvm_dirty_log *log,
2083 		      int *is_dirty, struct kvm_memory_slot **memslot)
2084 {
2085 	struct kvm_memslots *slots;
2086 	int i, as_id, id;
2087 	unsigned long n;
2088 	unsigned long any = 0;
2089 
2090 	/* Dirty ring tracking may be exclusive to dirty log tracking */
2091 	if (!kvm_use_dirty_bitmap(kvm))
2092 		return -ENXIO;
2093 
2094 	*memslot = NULL;
2095 	*is_dirty = 0;
2096 
2097 	as_id = log->slot >> 16;
2098 	id = (u16)log->slot;
2099 	if (as_id >= KVM_ADDRESS_SPACE_NUM || id >= KVM_USER_MEM_SLOTS)
2100 		return -EINVAL;
2101 
2102 	slots = __kvm_memslots(kvm, as_id);
2103 	*memslot = id_to_memslot(slots, id);
2104 	if (!(*memslot) || !(*memslot)->dirty_bitmap)
2105 		return -ENOENT;
2106 
2107 	kvm_arch_sync_dirty_log(kvm, *memslot);
2108 
2109 	n = kvm_dirty_bitmap_bytes(*memslot);
2110 
2111 	for (i = 0; !any && i < n/sizeof(long); ++i)
2112 		any = (*memslot)->dirty_bitmap[i];
2113 
2114 	if (copy_to_user(log->dirty_bitmap, (*memslot)->dirty_bitmap, n))
2115 		return -EFAULT;
2116 
2117 	if (any)
2118 		*is_dirty = 1;
2119 	return 0;
2120 }
2121 EXPORT_SYMBOL_GPL(kvm_get_dirty_log);
2122 
2123 #else /* CONFIG_KVM_GENERIC_DIRTYLOG_READ_PROTECT */
2124 /**
2125  * kvm_get_dirty_log_protect - get a snapshot of dirty pages
2126  *	and reenable dirty page tracking for the corresponding pages.
2127  * @kvm:	pointer to kvm instance
2128  * @log:	slot id and address to which we copy the log
2129  *
2130  * We need to keep it in mind that VCPU threads can write to the bitmap
2131  * concurrently. So, to avoid losing track of dirty pages we keep the
2132  * following order:
2133  *
2134  *    1. Take a snapshot of the bit and clear it if needed.
2135  *    2. Write protect the corresponding page.
2136  *    3. Copy the snapshot to the userspace.
2137  *    4. Upon return caller flushes TLB's if needed.
2138  *
2139  * Between 2 and 4, the guest may write to the page using the remaining TLB
2140  * entry.  This is not a problem because the page is reported dirty using
2141  * the snapshot taken before and step 4 ensures that writes done after
2142  * exiting to userspace will be logged for the next call.
2143  *
2144  */
kvm_get_dirty_log_protect(struct kvm * kvm,struct kvm_dirty_log * log)2145 static int kvm_get_dirty_log_protect(struct kvm *kvm, struct kvm_dirty_log *log)
2146 {
2147 	struct kvm_memslots *slots;
2148 	struct kvm_memory_slot *memslot;
2149 	int i, as_id, id;
2150 	unsigned long n;
2151 	unsigned long *dirty_bitmap;
2152 	unsigned long *dirty_bitmap_buffer;
2153 	bool flush;
2154 
2155 	/* Dirty ring tracking may be exclusive to dirty log tracking */
2156 	if (!kvm_use_dirty_bitmap(kvm))
2157 		return -ENXIO;
2158 
2159 	as_id = log->slot >> 16;
2160 	id = (u16)log->slot;
2161 	if (as_id >= KVM_ADDRESS_SPACE_NUM || id >= KVM_USER_MEM_SLOTS)
2162 		return -EINVAL;
2163 
2164 	slots = __kvm_memslots(kvm, as_id);
2165 	memslot = id_to_memslot(slots, id);
2166 	if (!memslot || !memslot->dirty_bitmap)
2167 		return -ENOENT;
2168 
2169 	dirty_bitmap = memslot->dirty_bitmap;
2170 
2171 	kvm_arch_sync_dirty_log(kvm, memslot);
2172 
2173 	n = kvm_dirty_bitmap_bytes(memslot);
2174 	flush = false;
2175 	if (kvm->manual_dirty_log_protect) {
2176 		/*
2177 		 * Unlike kvm_get_dirty_log, we always return false in *flush,
2178 		 * because no flush is needed until KVM_CLEAR_DIRTY_LOG.  There
2179 		 * is some code duplication between this function and
2180 		 * kvm_get_dirty_log, but hopefully all architecture
2181 		 * transition to kvm_get_dirty_log_protect and kvm_get_dirty_log
2182 		 * can be eliminated.
2183 		 */
2184 		dirty_bitmap_buffer = dirty_bitmap;
2185 	} else {
2186 		dirty_bitmap_buffer = kvm_second_dirty_bitmap(memslot);
2187 		memset(dirty_bitmap_buffer, 0, n);
2188 
2189 		KVM_MMU_LOCK(kvm);
2190 		for (i = 0; i < n / sizeof(long); i++) {
2191 			unsigned long mask;
2192 			gfn_t offset;
2193 
2194 			if (!dirty_bitmap[i])
2195 				continue;
2196 
2197 			flush = true;
2198 			mask = xchg(&dirty_bitmap[i], 0);
2199 			dirty_bitmap_buffer[i] = mask;
2200 
2201 			offset = i * BITS_PER_LONG;
2202 			kvm_arch_mmu_enable_log_dirty_pt_masked(kvm, memslot,
2203 								offset, mask);
2204 		}
2205 		KVM_MMU_UNLOCK(kvm);
2206 	}
2207 
2208 	if (flush)
2209 		kvm_flush_remote_tlbs_memslot(kvm, memslot);
2210 
2211 	if (copy_to_user(log->dirty_bitmap, dirty_bitmap_buffer, n))
2212 		return -EFAULT;
2213 	return 0;
2214 }
2215 
2216 
2217 /**
2218  * kvm_vm_ioctl_get_dirty_log - get and clear the log of dirty pages in a slot
2219  * @kvm: kvm instance
2220  * @log: slot id and address to which we copy the log
2221  *
2222  * Steps 1-4 below provide general overview of dirty page logging. See
2223  * kvm_get_dirty_log_protect() function description for additional details.
2224  *
2225  * We call kvm_get_dirty_log_protect() to handle steps 1-3, upon return we
2226  * always flush the TLB (step 4) even if previous step failed  and the dirty
2227  * bitmap may be corrupt. Regardless of previous outcome the KVM logging API
2228  * does not preclude user space subsequent dirty log read. Flushing TLB ensures
2229  * writes will be marked dirty for next log read.
2230  *
2231  *   1. Take a snapshot of the bit and clear it if needed.
2232  *   2. Write protect the corresponding page.
2233  *   3. Copy the snapshot to the userspace.
2234  *   4. Flush TLB's if needed.
2235  */
kvm_vm_ioctl_get_dirty_log(struct kvm * kvm,struct kvm_dirty_log * log)2236 static int kvm_vm_ioctl_get_dirty_log(struct kvm *kvm,
2237 				      struct kvm_dirty_log *log)
2238 {
2239 	int r;
2240 
2241 	mutex_lock(&kvm->slots_lock);
2242 
2243 	r = kvm_get_dirty_log_protect(kvm, log);
2244 
2245 	mutex_unlock(&kvm->slots_lock);
2246 	return r;
2247 }
2248 
2249 /**
2250  * kvm_clear_dirty_log_protect - clear dirty bits in the bitmap
2251  *	and reenable dirty page tracking for the corresponding pages.
2252  * @kvm:	pointer to kvm instance
2253  * @log:	slot id and address from which to fetch the bitmap of dirty pages
2254  */
kvm_clear_dirty_log_protect(struct kvm * kvm,struct kvm_clear_dirty_log * log)2255 static int kvm_clear_dirty_log_protect(struct kvm *kvm,
2256 				       struct kvm_clear_dirty_log *log)
2257 {
2258 	struct kvm_memslots *slots;
2259 	struct kvm_memory_slot *memslot;
2260 	int as_id, id;
2261 	gfn_t offset;
2262 	unsigned long i, n;
2263 	unsigned long *dirty_bitmap;
2264 	unsigned long *dirty_bitmap_buffer;
2265 	bool flush;
2266 
2267 	/* Dirty ring tracking may be exclusive to dirty log tracking */
2268 	if (!kvm_use_dirty_bitmap(kvm))
2269 		return -ENXIO;
2270 
2271 	as_id = log->slot >> 16;
2272 	id = (u16)log->slot;
2273 	if (as_id >= KVM_ADDRESS_SPACE_NUM || id >= KVM_USER_MEM_SLOTS)
2274 		return -EINVAL;
2275 
2276 	if (log->first_page & 63)
2277 		return -EINVAL;
2278 
2279 	slots = __kvm_memslots(kvm, as_id);
2280 	memslot = id_to_memslot(slots, id);
2281 	if (!memslot || !memslot->dirty_bitmap)
2282 		return -ENOENT;
2283 
2284 	dirty_bitmap = memslot->dirty_bitmap;
2285 
2286 	n = ALIGN(log->num_pages, BITS_PER_LONG) / 8;
2287 
2288 	if (log->first_page > memslot->npages ||
2289 	    log->num_pages > memslot->npages - log->first_page ||
2290 	    (log->num_pages < memslot->npages - log->first_page && (log->num_pages & 63)))
2291 	    return -EINVAL;
2292 
2293 	kvm_arch_sync_dirty_log(kvm, memslot);
2294 
2295 	flush = false;
2296 	dirty_bitmap_buffer = kvm_second_dirty_bitmap(memslot);
2297 	if (copy_from_user(dirty_bitmap_buffer, log->dirty_bitmap, n))
2298 		return -EFAULT;
2299 
2300 	KVM_MMU_LOCK(kvm);
2301 	for (offset = log->first_page, i = offset / BITS_PER_LONG,
2302 		 n = DIV_ROUND_UP(log->num_pages, BITS_PER_LONG); n--;
2303 	     i++, offset += BITS_PER_LONG) {
2304 		unsigned long mask = *dirty_bitmap_buffer++;
2305 		atomic_long_t *p = (atomic_long_t *) &dirty_bitmap[i];
2306 		if (!mask)
2307 			continue;
2308 
2309 		mask &= atomic_long_fetch_andnot(mask, p);
2310 
2311 		/*
2312 		 * mask contains the bits that really have been cleared.  This
2313 		 * never includes any bits beyond the length of the memslot (if
2314 		 * the length is not aligned to 64 pages), therefore it is not
2315 		 * a problem if userspace sets them in log->dirty_bitmap.
2316 		*/
2317 		if (mask) {
2318 			flush = true;
2319 			kvm_arch_mmu_enable_log_dirty_pt_masked(kvm, memslot,
2320 								offset, mask);
2321 		}
2322 	}
2323 	KVM_MMU_UNLOCK(kvm);
2324 
2325 	if (flush)
2326 		kvm_flush_remote_tlbs_memslot(kvm, memslot);
2327 
2328 	return 0;
2329 }
2330 
kvm_vm_ioctl_clear_dirty_log(struct kvm * kvm,struct kvm_clear_dirty_log * log)2331 static int kvm_vm_ioctl_clear_dirty_log(struct kvm *kvm,
2332 					struct kvm_clear_dirty_log *log)
2333 {
2334 	int r;
2335 
2336 	mutex_lock(&kvm->slots_lock);
2337 
2338 	r = kvm_clear_dirty_log_protect(kvm, log);
2339 
2340 	mutex_unlock(&kvm->slots_lock);
2341 	return r;
2342 }
2343 #endif /* CONFIG_KVM_GENERIC_DIRTYLOG_READ_PROTECT */
2344 
gfn_to_memslot(struct kvm * kvm,gfn_t gfn)2345 struct kvm_memory_slot *gfn_to_memslot(struct kvm *kvm, gfn_t gfn)
2346 {
2347 	return __gfn_to_memslot(kvm_memslots(kvm), gfn);
2348 }
2349 EXPORT_SYMBOL_GPL(gfn_to_memslot);
2350 
kvm_vcpu_gfn_to_memslot(struct kvm_vcpu * vcpu,gfn_t gfn)2351 struct kvm_memory_slot *kvm_vcpu_gfn_to_memslot(struct kvm_vcpu *vcpu, gfn_t gfn)
2352 {
2353 	struct kvm_memslots *slots = kvm_vcpu_memslots(vcpu);
2354 	u64 gen = slots->generation;
2355 	struct kvm_memory_slot *slot;
2356 
2357 	/*
2358 	 * This also protects against using a memslot from a different address space,
2359 	 * since different address spaces have different generation numbers.
2360 	 */
2361 	if (unlikely(gen != vcpu->last_used_slot_gen)) {
2362 		vcpu->last_used_slot = NULL;
2363 		vcpu->last_used_slot_gen = gen;
2364 	}
2365 
2366 	slot = try_get_memslot(vcpu->last_used_slot, gfn);
2367 	if (slot)
2368 		return slot;
2369 
2370 	/*
2371 	 * Fall back to searching all memslots. We purposely use
2372 	 * search_memslots() instead of __gfn_to_memslot() to avoid
2373 	 * thrashing the VM-wide last_used_slot in kvm_memslots.
2374 	 */
2375 	slot = search_memslots(slots, gfn, false);
2376 	if (slot) {
2377 		vcpu->last_used_slot = slot;
2378 		return slot;
2379 	}
2380 
2381 	return NULL;
2382 }
2383 
kvm_is_visible_gfn(struct kvm * kvm,gfn_t gfn)2384 bool kvm_is_visible_gfn(struct kvm *kvm, gfn_t gfn)
2385 {
2386 	struct kvm_memory_slot *memslot = gfn_to_memslot(kvm, gfn);
2387 
2388 	return kvm_is_visible_memslot(memslot);
2389 }
2390 EXPORT_SYMBOL_GPL(kvm_is_visible_gfn);
2391 
kvm_vcpu_is_visible_gfn(struct kvm_vcpu * vcpu,gfn_t gfn)2392 bool kvm_vcpu_is_visible_gfn(struct kvm_vcpu *vcpu, gfn_t gfn)
2393 {
2394 	struct kvm_memory_slot *memslot = kvm_vcpu_gfn_to_memslot(vcpu, gfn);
2395 
2396 	return kvm_is_visible_memslot(memslot);
2397 }
2398 EXPORT_SYMBOL_GPL(kvm_vcpu_is_visible_gfn);
2399 
kvm_host_page_size(struct kvm_vcpu * vcpu,gfn_t gfn)2400 unsigned long kvm_host_page_size(struct kvm_vcpu *vcpu, gfn_t gfn)
2401 {
2402 	struct vm_area_struct *vma;
2403 	unsigned long addr, size;
2404 
2405 	size = PAGE_SIZE;
2406 
2407 	addr = kvm_vcpu_gfn_to_hva_prot(vcpu, gfn, NULL);
2408 	if (kvm_is_error_hva(addr))
2409 		return PAGE_SIZE;
2410 
2411 	mmap_read_lock(current->mm);
2412 	vma = find_vma(current->mm, addr);
2413 	if (!vma)
2414 		goto out;
2415 
2416 	size = vma_kernel_pagesize(vma);
2417 
2418 out:
2419 	mmap_read_unlock(current->mm);
2420 
2421 	return size;
2422 }
2423 
memslot_is_readonly(const struct kvm_memory_slot * slot)2424 static bool memslot_is_readonly(const struct kvm_memory_slot *slot)
2425 {
2426 	return slot->flags & KVM_MEM_READONLY;
2427 }
2428 
__gfn_to_hva_many(const struct kvm_memory_slot * slot,gfn_t gfn,gfn_t * nr_pages,bool write)2429 static unsigned long __gfn_to_hva_many(const struct kvm_memory_slot *slot, gfn_t gfn,
2430 				       gfn_t *nr_pages, bool write)
2431 {
2432 	if (!slot || slot->flags & KVM_MEMSLOT_INVALID)
2433 		return KVM_HVA_ERR_BAD;
2434 
2435 	if (memslot_is_readonly(slot) && write)
2436 		return KVM_HVA_ERR_RO_BAD;
2437 
2438 	if (nr_pages)
2439 		*nr_pages = slot->npages - (gfn - slot->base_gfn);
2440 
2441 	return __gfn_to_hva_memslot(slot, gfn);
2442 }
2443 
gfn_to_hva_many(struct kvm_memory_slot * slot,gfn_t gfn,gfn_t * nr_pages)2444 static unsigned long gfn_to_hva_many(struct kvm_memory_slot *slot, gfn_t gfn,
2445 				     gfn_t *nr_pages)
2446 {
2447 	return __gfn_to_hva_many(slot, gfn, nr_pages, true);
2448 }
2449 
gfn_to_hva_memslot(struct kvm_memory_slot * slot,gfn_t gfn)2450 unsigned long gfn_to_hva_memslot(struct kvm_memory_slot *slot,
2451 					gfn_t gfn)
2452 {
2453 	return gfn_to_hva_many(slot, gfn, NULL);
2454 }
2455 EXPORT_SYMBOL_GPL(gfn_to_hva_memslot);
2456 
gfn_to_hva(struct kvm * kvm,gfn_t gfn)2457 unsigned long gfn_to_hva(struct kvm *kvm, gfn_t gfn)
2458 {
2459 	return gfn_to_hva_many(gfn_to_memslot(kvm, gfn), gfn, NULL);
2460 }
2461 EXPORT_SYMBOL_GPL(gfn_to_hva);
2462 
kvm_vcpu_gfn_to_hva(struct kvm_vcpu * vcpu,gfn_t gfn)2463 unsigned long kvm_vcpu_gfn_to_hva(struct kvm_vcpu *vcpu, gfn_t gfn)
2464 {
2465 	return gfn_to_hva_many(kvm_vcpu_gfn_to_memslot(vcpu, gfn), gfn, NULL);
2466 }
2467 EXPORT_SYMBOL_GPL(kvm_vcpu_gfn_to_hva);
2468 
2469 /*
2470  * Return the hva of a @gfn and the R/W attribute if possible.
2471  *
2472  * @slot: the kvm_memory_slot which contains @gfn
2473  * @gfn: the gfn to be translated
2474  * @writable: used to return the read/write attribute of the @slot if the hva
2475  * is valid and @writable is not NULL
2476  */
gfn_to_hva_memslot_prot(struct kvm_memory_slot * slot,gfn_t gfn,bool * writable)2477 unsigned long gfn_to_hva_memslot_prot(struct kvm_memory_slot *slot,
2478 				      gfn_t gfn, bool *writable)
2479 {
2480 	unsigned long hva = __gfn_to_hva_many(slot, gfn, NULL, false);
2481 
2482 	if (!kvm_is_error_hva(hva) && writable)
2483 		*writable = !memslot_is_readonly(slot);
2484 
2485 	return hva;
2486 }
2487 
gfn_to_hva_prot(struct kvm * kvm,gfn_t gfn,bool * writable)2488 unsigned long gfn_to_hva_prot(struct kvm *kvm, gfn_t gfn, bool *writable)
2489 {
2490 	struct kvm_memory_slot *slot = gfn_to_memslot(kvm, gfn);
2491 
2492 	return gfn_to_hva_memslot_prot(slot, gfn, writable);
2493 }
2494 
kvm_vcpu_gfn_to_hva_prot(struct kvm_vcpu * vcpu,gfn_t gfn,bool * writable)2495 unsigned long kvm_vcpu_gfn_to_hva_prot(struct kvm_vcpu *vcpu, gfn_t gfn, bool *writable)
2496 {
2497 	struct kvm_memory_slot *slot = kvm_vcpu_gfn_to_memslot(vcpu, gfn);
2498 
2499 	return gfn_to_hva_memslot_prot(slot, gfn, writable);
2500 }
2501 
check_user_page_hwpoison(unsigned long addr)2502 static inline int check_user_page_hwpoison(unsigned long addr)
2503 {
2504 	int rc, flags = FOLL_HWPOISON | FOLL_WRITE;
2505 
2506 	rc = get_user_pages(addr, 1, flags, NULL);
2507 	return rc == -EHWPOISON;
2508 }
2509 
2510 /*
2511  * The fast path to get the writable pfn which will be stored in @pfn,
2512  * true indicates success, otherwise false is returned.  It's also the
2513  * only part that runs if we can in atomic context.
2514  */
hva_to_pfn_fast(unsigned long addr,bool write_fault,bool * writable,kvm_pfn_t * pfn)2515 static bool hva_to_pfn_fast(unsigned long addr, bool write_fault,
2516 			    bool *writable, kvm_pfn_t *pfn)
2517 {
2518 	struct page *page[1];
2519 
2520 	/*
2521 	 * Fast pin a writable pfn only if it is a write fault request
2522 	 * or the caller allows to map a writable pfn for a read fault
2523 	 * request.
2524 	 */
2525 	if (!(write_fault || writable))
2526 		return false;
2527 
2528 	if (get_user_page_fast_only(addr, FOLL_WRITE, page)) {
2529 		*pfn = page_to_pfn(page[0]);
2530 
2531 		if (writable)
2532 			*writable = true;
2533 		return true;
2534 	}
2535 
2536 	return false;
2537 }
2538 
2539 /*
2540  * The slow path to get the pfn of the specified host virtual address,
2541  * 1 indicates success, -errno is returned if error is detected.
2542  */
hva_to_pfn_slow(unsigned long addr,bool * async,bool write_fault,bool interruptible,bool * writable,kvm_pfn_t * pfn)2543 static int hva_to_pfn_slow(unsigned long addr, bool *async, bool write_fault,
2544 			   bool interruptible, bool *writable, kvm_pfn_t *pfn)
2545 {
2546 	/*
2547 	 * When a VCPU accesses a page that is not mapped into the secondary
2548 	 * MMU, we lookup the page using GUP to map it, so the guest VCPU can
2549 	 * make progress. We always want to honor NUMA hinting faults in that
2550 	 * case, because GUP usage corresponds to memory accesses from the VCPU.
2551 	 * Otherwise, we'd not trigger NUMA hinting faults once a page is
2552 	 * mapped into the secondary MMU and gets accessed by a VCPU.
2553 	 *
2554 	 * Note that get_user_page_fast_only() and FOLL_WRITE for now
2555 	 * implicitly honor NUMA hinting faults and don't need this flag.
2556 	 */
2557 	unsigned int flags = FOLL_HWPOISON | FOLL_HONOR_NUMA_FAULT;
2558 	struct page *page;
2559 	int npages;
2560 
2561 	might_sleep();
2562 
2563 	if (writable)
2564 		*writable = write_fault;
2565 
2566 	if (write_fault)
2567 		flags |= FOLL_WRITE;
2568 	if (async)
2569 		flags |= FOLL_NOWAIT;
2570 	if (interruptible)
2571 		flags |= FOLL_INTERRUPTIBLE;
2572 
2573 	npages = get_user_pages_unlocked(addr, 1, &page, flags);
2574 	if (npages != 1)
2575 		return npages;
2576 
2577 	/* map read fault as writable if possible */
2578 	if (unlikely(!write_fault) && writable) {
2579 		struct page *wpage;
2580 
2581 		if (get_user_page_fast_only(addr, FOLL_WRITE, &wpage)) {
2582 			*writable = true;
2583 			put_page(page);
2584 			page = wpage;
2585 		}
2586 	}
2587 	*pfn = page_to_pfn(page);
2588 	return npages;
2589 }
2590 
vma_is_valid(struct vm_area_struct * vma,bool write_fault)2591 static bool vma_is_valid(struct vm_area_struct *vma, bool write_fault)
2592 {
2593 	if (unlikely(!(vma->vm_flags & VM_READ)))
2594 		return false;
2595 
2596 	if (write_fault && (unlikely(!(vma->vm_flags & VM_WRITE))))
2597 		return false;
2598 
2599 	return true;
2600 }
2601 
kvm_try_get_pfn(kvm_pfn_t pfn)2602 static int kvm_try_get_pfn(kvm_pfn_t pfn)
2603 {
2604 	struct page *page = kvm_pfn_to_refcounted_page(pfn);
2605 
2606 	if (!page)
2607 		return 1;
2608 
2609 	return get_page_unless_zero(page);
2610 }
2611 
hva_to_pfn_remapped(struct vm_area_struct * vma,unsigned long addr,bool write_fault,bool * writable,kvm_pfn_t * p_pfn)2612 static int hva_to_pfn_remapped(struct vm_area_struct *vma,
2613 			       unsigned long addr, bool write_fault,
2614 			       bool *writable, kvm_pfn_t *p_pfn)
2615 {
2616 	kvm_pfn_t pfn;
2617 	pte_t *ptep;
2618 	pte_t pte;
2619 	spinlock_t *ptl;
2620 	int r;
2621 
2622 	r = follow_pte(vma->vm_mm, addr, &ptep, &ptl);
2623 	if (r) {
2624 		/*
2625 		 * get_user_pages fails for VM_IO and VM_PFNMAP vmas and does
2626 		 * not call the fault handler, so do it here.
2627 		 */
2628 		bool unlocked = false;
2629 		r = fixup_user_fault(current->mm, addr,
2630 				     (write_fault ? FAULT_FLAG_WRITE : 0),
2631 				     &unlocked);
2632 		if (unlocked)
2633 			return -EAGAIN;
2634 		if (r)
2635 			return r;
2636 
2637 		r = follow_pte(vma->vm_mm, addr, &ptep, &ptl);
2638 		if (r)
2639 			return r;
2640 	}
2641 
2642 	pte = ptep_get(ptep);
2643 
2644 	if (write_fault && !pte_write(pte)) {
2645 		pfn = KVM_PFN_ERR_RO_FAULT;
2646 		goto out;
2647 	}
2648 
2649 	if (writable)
2650 		*writable = pte_write(pte);
2651 	pfn = pte_pfn(pte);
2652 
2653 	/*
2654 	 * Get a reference here because callers of *hva_to_pfn* and
2655 	 * *gfn_to_pfn* ultimately call kvm_release_pfn_clean on the
2656 	 * returned pfn.  This is only needed if the VMA has VM_MIXEDMAP
2657 	 * set, but the kvm_try_get_pfn/kvm_release_pfn_clean pair will
2658 	 * simply do nothing for reserved pfns.
2659 	 *
2660 	 * Whoever called remap_pfn_range is also going to call e.g.
2661 	 * unmap_mapping_range before the underlying pages are freed,
2662 	 * causing a call to our MMU notifier.
2663 	 *
2664 	 * Certain IO or PFNMAP mappings can be backed with valid
2665 	 * struct pages, but be allocated without refcounting e.g.,
2666 	 * tail pages of non-compound higher order allocations, which
2667 	 * would then underflow the refcount when the caller does the
2668 	 * required put_page. Don't allow those pages here.
2669 	 */
2670 	if (!kvm_try_get_pfn(pfn))
2671 		r = -EFAULT;
2672 
2673 out:
2674 	pte_unmap_unlock(ptep, ptl);
2675 	*p_pfn = pfn;
2676 
2677 	return r;
2678 }
2679 
2680 /*
2681  * Pin guest page in memory and return its pfn.
2682  * @addr: host virtual address which maps memory to the guest
2683  * @atomic: whether this function can sleep
2684  * @interruptible: whether the process can be interrupted by non-fatal signals
2685  * @async: whether this function need to wait IO complete if the
2686  *         host page is not in the memory
2687  * @write_fault: whether we should get a writable host page
2688  * @writable: whether it allows to map a writable host page for !@write_fault
2689  *
2690  * The function will map a writable host page for these two cases:
2691  * 1): @write_fault = true
2692  * 2): @write_fault = false && @writable, @writable will tell the caller
2693  *     whether the mapping is writable.
2694  */
hva_to_pfn(unsigned long addr,bool atomic,bool interruptible,bool * async,bool write_fault,bool * writable)2695 kvm_pfn_t hva_to_pfn(unsigned long addr, bool atomic, bool interruptible,
2696 		     bool *async, bool write_fault, bool *writable)
2697 {
2698 	struct vm_area_struct *vma;
2699 	kvm_pfn_t pfn;
2700 	int npages, r;
2701 
2702 	/* we can do it either atomically or asynchronously, not both */
2703 	BUG_ON(atomic && async);
2704 
2705 	if (hva_to_pfn_fast(addr, write_fault, writable, &pfn))
2706 		return pfn;
2707 
2708 	if (atomic)
2709 		return KVM_PFN_ERR_FAULT;
2710 
2711 	npages = hva_to_pfn_slow(addr, async, write_fault, interruptible,
2712 				 writable, &pfn);
2713 	if (npages == 1)
2714 		return pfn;
2715 	if (npages == -EINTR)
2716 		return KVM_PFN_ERR_SIGPENDING;
2717 
2718 	mmap_read_lock(current->mm);
2719 	if (npages == -EHWPOISON ||
2720 	      (!async && check_user_page_hwpoison(addr))) {
2721 		pfn = KVM_PFN_ERR_HWPOISON;
2722 		goto exit;
2723 	}
2724 
2725 retry:
2726 	vma = vma_lookup(current->mm, addr);
2727 
2728 	if (vma == NULL)
2729 		pfn = KVM_PFN_ERR_FAULT;
2730 	else if (vma->vm_flags & (VM_IO | VM_PFNMAP)) {
2731 		r = hva_to_pfn_remapped(vma, addr, write_fault, writable, &pfn);
2732 		if (r == -EAGAIN)
2733 			goto retry;
2734 		if (r < 0)
2735 			pfn = KVM_PFN_ERR_FAULT;
2736 	} else {
2737 		if (async && vma_is_valid(vma, write_fault))
2738 			*async = true;
2739 		pfn = KVM_PFN_ERR_FAULT;
2740 	}
2741 exit:
2742 	mmap_read_unlock(current->mm);
2743 	return pfn;
2744 }
2745 
__gfn_to_pfn_memslot(const struct kvm_memory_slot * slot,gfn_t gfn,bool atomic,bool interruptible,bool * async,bool write_fault,bool * writable,hva_t * hva)2746 kvm_pfn_t __gfn_to_pfn_memslot(const struct kvm_memory_slot *slot, gfn_t gfn,
2747 			       bool atomic, bool interruptible, bool *async,
2748 			       bool write_fault, bool *writable, hva_t *hva)
2749 {
2750 	unsigned long addr = __gfn_to_hva_many(slot, gfn, NULL, write_fault);
2751 
2752 	if (hva)
2753 		*hva = addr;
2754 
2755 	if (addr == KVM_HVA_ERR_RO_BAD) {
2756 		if (writable)
2757 			*writable = false;
2758 		return KVM_PFN_ERR_RO_FAULT;
2759 	}
2760 
2761 	if (kvm_is_error_hva(addr)) {
2762 		if (writable)
2763 			*writable = false;
2764 		return KVM_PFN_NOSLOT;
2765 	}
2766 
2767 	/* Do not map writable pfn in the readonly memslot. */
2768 	if (writable && memslot_is_readonly(slot)) {
2769 		*writable = false;
2770 		writable = NULL;
2771 	}
2772 
2773 	return hva_to_pfn(addr, atomic, interruptible, async, write_fault,
2774 			  writable);
2775 }
2776 EXPORT_SYMBOL_GPL(__gfn_to_pfn_memslot);
2777 
gfn_to_pfn_prot(struct kvm * kvm,gfn_t gfn,bool write_fault,bool * writable)2778 kvm_pfn_t gfn_to_pfn_prot(struct kvm *kvm, gfn_t gfn, bool write_fault,
2779 		      bool *writable)
2780 {
2781 	return __gfn_to_pfn_memslot(gfn_to_memslot(kvm, gfn), gfn, false, false,
2782 				    NULL, write_fault, writable, NULL);
2783 }
2784 EXPORT_SYMBOL_GPL(gfn_to_pfn_prot);
2785 
gfn_to_pfn_memslot(const struct kvm_memory_slot * slot,gfn_t gfn)2786 kvm_pfn_t gfn_to_pfn_memslot(const struct kvm_memory_slot *slot, gfn_t gfn)
2787 {
2788 	return __gfn_to_pfn_memslot(slot, gfn, false, false, NULL, true,
2789 				    NULL, NULL);
2790 }
2791 EXPORT_SYMBOL_GPL(gfn_to_pfn_memslot);
2792 
gfn_to_pfn_memslot_atomic(const struct kvm_memory_slot * slot,gfn_t gfn)2793 kvm_pfn_t gfn_to_pfn_memslot_atomic(const struct kvm_memory_slot *slot, gfn_t gfn)
2794 {
2795 	return __gfn_to_pfn_memslot(slot, gfn, true, false, NULL, true,
2796 				    NULL, NULL);
2797 }
2798 EXPORT_SYMBOL_GPL(gfn_to_pfn_memslot_atomic);
2799 
kvm_vcpu_gfn_to_pfn_atomic(struct kvm_vcpu * vcpu,gfn_t gfn)2800 kvm_pfn_t kvm_vcpu_gfn_to_pfn_atomic(struct kvm_vcpu *vcpu, gfn_t gfn)
2801 {
2802 	return gfn_to_pfn_memslot_atomic(kvm_vcpu_gfn_to_memslot(vcpu, gfn), gfn);
2803 }
2804 EXPORT_SYMBOL_GPL(kvm_vcpu_gfn_to_pfn_atomic);
2805 
gfn_to_pfn(struct kvm * kvm,gfn_t gfn)2806 kvm_pfn_t gfn_to_pfn(struct kvm *kvm, gfn_t gfn)
2807 {
2808 	return gfn_to_pfn_memslot(gfn_to_memslot(kvm, gfn), gfn);
2809 }
2810 EXPORT_SYMBOL_GPL(gfn_to_pfn);
2811 
kvm_vcpu_gfn_to_pfn(struct kvm_vcpu * vcpu,gfn_t gfn)2812 kvm_pfn_t kvm_vcpu_gfn_to_pfn(struct kvm_vcpu *vcpu, gfn_t gfn)
2813 {
2814 	return gfn_to_pfn_memslot(kvm_vcpu_gfn_to_memslot(vcpu, gfn), gfn);
2815 }
2816 EXPORT_SYMBOL_GPL(kvm_vcpu_gfn_to_pfn);
2817 
gfn_to_page_many_atomic(struct kvm_memory_slot * slot,gfn_t gfn,struct page ** pages,int nr_pages)2818 int gfn_to_page_many_atomic(struct kvm_memory_slot *slot, gfn_t gfn,
2819 			    struct page **pages, int nr_pages)
2820 {
2821 	unsigned long addr;
2822 	gfn_t entry = 0;
2823 
2824 	addr = gfn_to_hva_many(slot, gfn, &entry);
2825 	if (kvm_is_error_hva(addr))
2826 		return -1;
2827 
2828 	if (entry < nr_pages)
2829 		return 0;
2830 
2831 	return get_user_pages_fast_only(addr, nr_pages, FOLL_WRITE, pages);
2832 }
2833 EXPORT_SYMBOL_GPL(gfn_to_page_many_atomic);
2834 
2835 /*
2836  * Do not use this helper unless you are absolutely certain the gfn _must_ be
2837  * backed by 'struct page'.  A valid example is if the backing memslot is
2838  * controlled by KVM.  Note, if the returned page is valid, it's refcount has
2839  * been elevated by gfn_to_pfn().
2840  */
gfn_to_page(struct kvm * kvm,gfn_t gfn)2841 struct page *gfn_to_page(struct kvm *kvm, gfn_t gfn)
2842 {
2843 	struct page *page;
2844 	kvm_pfn_t pfn;
2845 
2846 	pfn = gfn_to_pfn(kvm, gfn);
2847 
2848 	if (is_error_noslot_pfn(pfn))
2849 		return KVM_ERR_PTR_BAD_PAGE;
2850 
2851 	page = kvm_pfn_to_refcounted_page(pfn);
2852 	if (!page)
2853 		return KVM_ERR_PTR_BAD_PAGE;
2854 
2855 	return page;
2856 }
2857 EXPORT_SYMBOL_GPL(gfn_to_page);
2858 
kvm_release_pfn(kvm_pfn_t pfn,bool dirty)2859 void kvm_release_pfn(kvm_pfn_t pfn, bool dirty)
2860 {
2861 	if (dirty)
2862 		kvm_release_pfn_dirty(pfn);
2863 	else
2864 		kvm_release_pfn_clean(pfn);
2865 }
2866 
kvm_vcpu_map(struct kvm_vcpu * vcpu,gfn_t gfn,struct kvm_host_map * map)2867 int kvm_vcpu_map(struct kvm_vcpu *vcpu, gfn_t gfn, struct kvm_host_map *map)
2868 {
2869 	kvm_pfn_t pfn;
2870 	void *hva = NULL;
2871 	struct page *page = KVM_UNMAPPED_PAGE;
2872 
2873 	if (!map)
2874 		return -EINVAL;
2875 
2876 	pfn = gfn_to_pfn(vcpu->kvm, gfn);
2877 	if (is_error_noslot_pfn(pfn))
2878 		return -EINVAL;
2879 
2880 	if (pfn_valid(pfn)) {
2881 		page = pfn_to_page(pfn);
2882 		hva = kmap(page);
2883 #ifdef CONFIG_HAS_IOMEM
2884 	} else {
2885 		hva = memremap(pfn_to_hpa(pfn), PAGE_SIZE, MEMREMAP_WB);
2886 #endif
2887 	}
2888 
2889 	if (!hva)
2890 		return -EFAULT;
2891 
2892 	map->page = page;
2893 	map->hva = hva;
2894 	map->pfn = pfn;
2895 	map->gfn = gfn;
2896 
2897 	return 0;
2898 }
2899 EXPORT_SYMBOL_GPL(kvm_vcpu_map);
2900 
kvm_vcpu_unmap(struct kvm_vcpu * vcpu,struct kvm_host_map * map,bool dirty)2901 void kvm_vcpu_unmap(struct kvm_vcpu *vcpu, struct kvm_host_map *map, bool dirty)
2902 {
2903 	if (!map)
2904 		return;
2905 
2906 	if (!map->hva)
2907 		return;
2908 
2909 	if (map->page != KVM_UNMAPPED_PAGE)
2910 		kunmap(map->page);
2911 #ifdef CONFIG_HAS_IOMEM
2912 	else
2913 		memunmap(map->hva);
2914 #endif
2915 
2916 	if (dirty)
2917 		kvm_vcpu_mark_page_dirty(vcpu, map->gfn);
2918 
2919 	kvm_release_pfn(map->pfn, dirty);
2920 
2921 	map->hva = NULL;
2922 	map->page = NULL;
2923 }
2924 EXPORT_SYMBOL_GPL(kvm_vcpu_unmap);
2925 
kvm_is_ad_tracked_page(struct page * page)2926 static bool kvm_is_ad_tracked_page(struct page *page)
2927 {
2928 	/*
2929 	 * Per page-flags.h, pages tagged PG_reserved "should in general not be
2930 	 * touched (e.g. set dirty) except by its owner".
2931 	 */
2932 	return !PageReserved(page);
2933 }
2934 
kvm_set_page_dirty(struct page * page)2935 static void kvm_set_page_dirty(struct page *page)
2936 {
2937 	if (kvm_is_ad_tracked_page(page))
2938 		SetPageDirty(page);
2939 }
2940 
kvm_set_page_accessed(struct page * page)2941 static void kvm_set_page_accessed(struct page *page)
2942 {
2943 	if (kvm_is_ad_tracked_page(page))
2944 		mark_page_accessed(page);
2945 }
2946 
kvm_release_page_clean(struct page * page)2947 void kvm_release_page_clean(struct page *page)
2948 {
2949 	WARN_ON(is_error_page(page));
2950 
2951 	kvm_set_page_accessed(page);
2952 	put_page(page);
2953 }
2954 EXPORT_SYMBOL_GPL(kvm_release_page_clean);
2955 
kvm_release_pfn_clean(kvm_pfn_t pfn)2956 void kvm_release_pfn_clean(kvm_pfn_t pfn)
2957 {
2958 	struct page *page;
2959 
2960 	if (is_error_noslot_pfn(pfn))
2961 		return;
2962 
2963 	page = kvm_pfn_to_refcounted_page(pfn);
2964 	if (!page)
2965 		return;
2966 
2967 	kvm_release_page_clean(page);
2968 }
2969 EXPORT_SYMBOL_GPL(kvm_release_pfn_clean);
2970 
kvm_release_page_dirty(struct page * page)2971 void kvm_release_page_dirty(struct page *page)
2972 {
2973 	WARN_ON(is_error_page(page));
2974 
2975 	kvm_set_page_dirty(page);
2976 	kvm_release_page_clean(page);
2977 }
2978 EXPORT_SYMBOL_GPL(kvm_release_page_dirty);
2979 
kvm_release_pfn_dirty(kvm_pfn_t pfn)2980 void kvm_release_pfn_dirty(kvm_pfn_t pfn)
2981 {
2982 	struct page *page;
2983 
2984 	if (is_error_noslot_pfn(pfn))
2985 		return;
2986 
2987 	page = kvm_pfn_to_refcounted_page(pfn);
2988 	if (!page)
2989 		return;
2990 
2991 	kvm_release_page_dirty(page);
2992 }
2993 EXPORT_SYMBOL_GPL(kvm_release_pfn_dirty);
2994 
2995 /*
2996  * Note, checking for an error/noslot pfn is the caller's responsibility when
2997  * directly marking a page dirty/accessed.  Unlike the "release" helpers, the
2998  * "set" helpers are not to be used when the pfn might point at garbage.
2999  */
kvm_set_pfn_dirty(kvm_pfn_t pfn)3000 void kvm_set_pfn_dirty(kvm_pfn_t pfn)
3001 {
3002 	if (WARN_ON(is_error_noslot_pfn(pfn)))
3003 		return;
3004 
3005 	if (pfn_valid(pfn))
3006 		kvm_set_page_dirty(pfn_to_page(pfn));
3007 }
3008 EXPORT_SYMBOL_GPL(kvm_set_pfn_dirty);
3009 
kvm_set_pfn_accessed(kvm_pfn_t pfn)3010 void kvm_set_pfn_accessed(kvm_pfn_t pfn)
3011 {
3012 	if (WARN_ON(is_error_noslot_pfn(pfn)))
3013 		return;
3014 
3015 	if (pfn_valid(pfn))
3016 		kvm_set_page_accessed(pfn_to_page(pfn));
3017 }
3018 EXPORT_SYMBOL_GPL(kvm_set_pfn_accessed);
3019 
next_segment(unsigned long len,int offset)3020 static int next_segment(unsigned long len, int offset)
3021 {
3022 	if (len > PAGE_SIZE - offset)
3023 		return PAGE_SIZE - offset;
3024 	else
3025 		return len;
3026 }
3027 
__kvm_read_guest_page(struct kvm_memory_slot * slot,gfn_t gfn,void * data,int offset,int len)3028 static int __kvm_read_guest_page(struct kvm_memory_slot *slot, gfn_t gfn,
3029 				 void *data, int offset, int len)
3030 {
3031 	int r;
3032 	unsigned long addr;
3033 
3034 	addr = gfn_to_hva_memslot_prot(slot, gfn, NULL);
3035 	if (kvm_is_error_hva(addr))
3036 		return -EFAULT;
3037 	r = __copy_from_user(data, (void __user *)addr + offset, len);
3038 	if (r)
3039 		return -EFAULT;
3040 	return 0;
3041 }
3042 
kvm_read_guest_page(struct kvm * kvm,gfn_t gfn,void * data,int offset,int len)3043 int kvm_read_guest_page(struct kvm *kvm, gfn_t gfn, void *data, int offset,
3044 			int len)
3045 {
3046 	struct kvm_memory_slot *slot = gfn_to_memslot(kvm, gfn);
3047 
3048 	return __kvm_read_guest_page(slot, gfn, data, offset, len);
3049 }
3050 EXPORT_SYMBOL_GPL(kvm_read_guest_page);
3051 
kvm_vcpu_read_guest_page(struct kvm_vcpu * vcpu,gfn_t gfn,void * data,int offset,int len)3052 int kvm_vcpu_read_guest_page(struct kvm_vcpu *vcpu, gfn_t gfn, void *data,
3053 			     int offset, int len)
3054 {
3055 	struct kvm_memory_slot *slot = kvm_vcpu_gfn_to_memslot(vcpu, gfn);
3056 
3057 	return __kvm_read_guest_page(slot, gfn, data, offset, len);
3058 }
3059 EXPORT_SYMBOL_GPL(kvm_vcpu_read_guest_page);
3060 
kvm_read_guest(struct kvm * kvm,gpa_t gpa,void * data,unsigned long len)3061 int kvm_read_guest(struct kvm *kvm, gpa_t gpa, void *data, unsigned long len)
3062 {
3063 	gfn_t gfn = gpa >> PAGE_SHIFT;
3064 	int seg;
3065 	int offset = offset_in_page(gpa);
3066 	int ret;
3067 
3068 	while ((seg = next_segment(len, offset)) != 0) {
3069 		ret = kvm_read_guest_page(kvm, gfn, data, offset, seg);
3070 		if (ret < 0)
3071 			return ret;
3072 		offset = 0;
3073 		len -= seg;
3074 		data += seg;
3075 		++gfn;
3076 	}
3077 	return 0;
3078 }
3079 EXPORT_SYMBOL_GPL(kvm_read_guest);
3080 
kvm_vcpu_read_guest(struct kvm_vcpu * vcpu,gpa_t gpa,void * data,unsigned long len)3081 int kvm_vcpu_read_guest(struct kvm_vcpu *vcpu, gpa_t gpa, void *data, unsigned long len)
3082 {
3083 	gfn_t gfn = gpa >> PAGE_SHIFT;
3084 	int seg;
3085 	int offset = offset_in_page(gpa);
3086 	int ret;
3087 
3088 	while ((seg = next_segment(len, offset)) != 0) {
3089 		ret = kvm_vcpu_read_guest_page(vcpu, gfn, data, offset, seg);
3090 		if (ret < 0)
3091 			return ret;
3092 		offset = 0;
3093 		len -= seg;
3094 		data += seg;
3095 		++gfn;
3096 	}
3097 	return 0;
3098 }
3099 EXPORT_SYMBOL_GPL(kvm_vcpu_read_guest);
3100 
__kvm_read_guest_atomic(struct kvm_memory_slot * slot,gfn_t gfn,void * data,int offset,unsigned long len)3101 static int __kvm_read_guest_atomic(struct kvm_memory_slot *slot, gfn_t gfn,
3102 			           void *data, int offset, unsigned long len)
3103 {
3104 	int r;
3105 	unsigned long addr;
3106 
3107 	addr = gfn_to_hva_memslot_prot(slot, gfn, NULL);
3108 	if (kvm_is_error_hva(addr))
3109 		return -EFAULT;
3110 	pagefault_disable();
3111 	r = __copy_from_user_inatomic(data, (void __user *)addr + offset, len);
3112 	pagefault_enable();
3113 	if (r)
3114 		return -EFAULT;
3115 	return 0;
3116 }
3117 
kvm_vcpu_read_guest_atomic(struct kvm_vcpu * vcpu,gpa_t gpa,void * data,unsigned long len)3118 int kvm_vcpu_read_guest_atomic(struct kvm_vcpu *vcpu, gpa_t gpa,
3119 			       void *data, unsigned long len)
3120 {
3121 	gfn_t gfn = gpa >> PAGE_SHIFT;
3122 	struct kvm_memory_slot *slot = kvm_vcpu_gfn_to_memslot(vcpu, gfn);
3123 	int offset = offset_in_page(gpa);
3124 
3125 	return __kvm_read_guest_atomic(slot, gfn, data, offset, len);
3126 }
3127 EXPORT_SYMBOL_GPL(kvm_vcpu_read_guest_atomic);
3128 
__kvm_write_guest_page(struct kvm * kvm,struct kvm_memory_slot * memslot,gfn_t gfn,const void * data,int offset,int len)3129 static int __kvm_write_guest_page(struct kvm *kvm,
3130 				  struct kvm_memory_slot *memslot, gfn_t gfn,
3131 			          const void *data, int offset, int len)
3132 {
3133 	int r;
3134 	unsigned long addr;
3135 
3136 	addr = gfn_to_hva_memslot(memslot, gfn);
3137 	if (kvm_is_error_hva(addr))
3138 		return -EFAULT;
3139 	r = __copy_to_user((void __user *)addr + offset, data, len);
3140 	if (r)
3141 		return -EFAULT;
3142 	mark_page_dirty_in_slot(kvm, memslot, gfn);
3143 	return 0;
3144 }
3145 
kvm_write_guest_page(struct kvm * kvm,gfn_t gfn,const void * data,int offset,int len)3146 int kvm_write_guest_page(struct kvm *kvm, gfn_t gfn,
3147 			 const void *data, int offset, int len)
3148 {
3149 	struct kvm_memory_slot *slot = gfn_to_memslot(kvm, gfn);
3150 
3151 	return __kvm_write_guest_page(kvm, slot, gfn, data, offset, len);
3152 }
3153 EXPORT_SYMBOL_GPL(kvm_write_guest_page);
3154 
kvm_vcpu_write_guest_page(struct kvm_vcpu * vcpu,gfn_t gfn,const void * data,int offset,int len)3155 int kvm_vcpu_write_guest_page(struct kvm_vcpu *vcpu, gfn_t gfn,
3156 			      const void *data, int offset, int len)
3157 {
3158 	struct kvm_memory_slot *slot = kvm_vcpu_gfn_to_memslot(vcpu, gfn);
3159 
3160 	return __kvm_write_guest_page(vcpu->kvm, slot, gfn, data, offset, len);
3161 }
3162 EXPORT_SYMBOL_GPL(kvm_vcpu_write_guest_page);
3163 
kvm_write_guest(struct kvm * kvm,gpa_t gpa,const void * data,unsigned long len)3164 int kvm_write_guest(struct kvm *kvm, gpa_t gpa, const void *data,
3165 		    unsigned long len)
3166 {
3167 	gfn_t gfn = gpa >> PAGE_SHIFT;
3168 	int seg;
3169 	int offset = offset_in_page(gpa);
3170 	int ret;
3171 
3172 	while ((seg = next_segment(len, offset)) != 0) {
3173 		ret = kvm_write_guest_page(kvm, gfn, data, offset, seg);
3174 		if (ret < 0)
3175 			return ret;
3176 		offset = 0;
3177 		len -= seg;
3178 		data += seg;
3179 		++gfn;
3180 	}
3181 	return 0;
3182 }
3183 EXPORT_SYMBOL_GPL(kvm_write_guest);
3184 
kvm_vcpu_write_guest(struct kvm_vcpu * vcpu,gpa_t gpa,const void * data,unsigned long len)3185 int kvm_vcpu_write_guest(struct kvm_vcpu *vcpu, gpa_t gpa, const void *data,
3186 		         unsigned long len)
3187 {
3188 	gfn_t gfn = gpa >> PAGE_SHIFT;
3189 	int seg;
3190 	int offset = offset_in_page(gpa);
3191 	int ret;
3192 
3193 	while ((seg = next_segment(len, offset)) != 0) {
3194 		ret = kvm_vcpu_write_guest_page(vcpu, gfn, data, offset, seg);
3195 		if (ret < 0)
3196 			return ret;
3197 		offset = 0;
3198 		len -= seg;
3199 		data += seg;
3200 		++gfn;
3201 	}
3202 	return 0;
3203 }
3204 EXPORT_SYMBOL_GPL(kvm_vcpu_write_guest);
3205 
__kvm_gfn_to_hva_cache_init(struct kvm_memslots * slots,struct gfn_to_hva_cache * ghc,gpa_t gpa,unsigned long len)3206 static int __kvm_gfn_to_hva_cache_init(struct kvm_memslots *slots,
3207 				       struct gfn_to_hva_cache *ghc,
3208 				       gpa_t gpa, unsigned long len)
3209 {
3210 	int offset = offset_in_page(gpa);
3211 	gfn_t start_gfn = gpa >> PAGE_SHIFT;
3212 	gfn_t end_gfn = (gpa + len - 1) >> PAGE_SHIFT;
3213 	gfn_t nr_pages_needed = end_gfn - start_gfn + 1;
3214 	gfn_t nr_pages_avail;
3215 
3216 	/* Update ghc->generation before performing any error checks. */
3217 	ghc->generation = slots->generation;
3218 
3219 	if (start_gfn > end_gfn) {
3220 		ghc->hva = KVM_HVA_ERR_BAD;
3221 		return -EINVAL;
3222 	}
3223 
3224 	/*
3225 	 * If the requested region crosses two memslots, we still
3226 	 * verify that the entire region is valid here.
3227 	 */
3228 	for ( ; start_gfn <= end_gfn; start_gfn += nr_pages_avail) {
3229 		ghc->memslot = __gfn_to_memslot(slots, start_gfn);
3230 		ghc->hva = gfn_to_hva_many(ghc->memslot, start_gfn,
3231 					   &nr_pages_avail);
3232 		if (kvm_is_error_hva(ghc->hva))
3233 			return -EFAULT;
3234 	}
3235 
3236 	/* Use the slow path for cross page reads and writes. */
3237 	if (nr_pages_needed == 1)
3238 		ghc->hva += offset;
3239 	else
3240 		ghc->memslot = NULL;
3241 
3242 	ghc->gpa = gpa;
3243 	ghc->len = len;
3244 	return 0;
3245 }
3246 
kvm_gfn_to_hva_cache_init(struct kvm * kvm,struct gfn_to_hva_cache * ghc,gpa_t gpa,unsigned long len)3247 int kvm_gfn_to_hva_cache_init(struct kvm *kvm, struct gfn_to_hva_cache *ghc,
3248 			      gpa_t gpa, unsigned long len)
3249 {
3250 	struct kvm_memslots *slots = kvm_memslots(kvm);
3251 	return __kvm_gfn_to_hva_cache_init(slots, ghc, gpa, len);
3252 }
3253 EXPORT_SYMBOL_GPL(kvm_gfn_to_hva_cache_init);
3254 
kvm_write_guest_offset_cached(struct kvm * kvm,struct gfn_to_hva_cache * ghc,void * data,unsigned int offset,unsigned long len)3255 int kvm_write_guest_offset_cached(struct kvm *kvm, struct gfn_to_hva_cache *ghc,
3256 				  void *data, unsigned int offset,
3257 				  unsigned long len)
3258 {
3259 	struct kvm_memslots *slots = kvm_memslots(kvm);
3260 	int r;
3261 	gpa_t gpa = ghc->gpa + offset;
3262 
3263 	if (WARN_ON_ONCE(len + offset > ghc->len))
3264 		return -EINVAL;
3265 
3266 	if (slots->generation != ghc->generation) {
3267 		if (__kvm_gfn_to_hva_cache_init(slots, ghc, ghc->gpa, ghc->len))
3268 			return -EFAULT;
3269 	}
3270 
3271 	if (kvm_is_error_hva(ghc->hva))
3272 		return -EFAULT;
3273 
3274 	if (unlikely(!ghc->memslot))
3275 		return kvm_write_guest(kvm, gpa, data, len);
3276 
3277 	r = __copy_to_user((void __user *)ghc->hva + offset, data, len);
3278 	if (r)
3279 		return -EFAULT;
3280 	mark_page_dirty_in_slot(kvm, ghc->memslot, gpa >> PAGE_SHIFT);
3281 
3282 	return 0;
3283 }
3284 EXPORT_SYMBOL_GPL(kvm_write_guest_offset_cached);
3285 
kvm_write_guest_cached(struct kvm * kvm,struct gfn_to_hva_cache * ghc,void * data,unsigned long len)3286 int kvm_write_guest_cached(struct kvm *kvm, struct gfn_to_hva_cache *ghc,
3287 			   void *data, unsigned long len)
3288 {
3289 	return kvm_write_guest_offset_cached(kvm, ghc, data, 0, len);
3290 }
3291 EXPORT_SYMBOL_GPL(kvm_write_guest_cached);
3292 
kvm_read_guest_offset_cached(struct kvm * kvm,struct gfn_to_hva_cache * ghc,void * data,unsigned int offset,unsigned long len)3293 int kvm_read_guest_offset_cached(struct kvm *kvm, struct gfn_to_hva_cache *ghc,
3294 				 void *data, unsigned int offset,
3295 				 unsigned long len)
3296 {
3297 	struct kvm_memslots *slots = kvm_memslots(kvm);
3298 	int r;
3299 	gpa_t gpa = ghc->gpa + offset;
3300 
3301 	if (WARN_ON_ONCE(len + offset > ghc->len))
3302 		return -EINVAL;
3303 
3304 	if (slots->generation != ghc->generation) {
3305 		if (__kvm_gfn_to_hva_cache_init(slots, ghc, ghc->gpa, ghc->len))
3306 			return -EFAULT;
3307 	}
3308 
3309 	if (kvm_is_error_hva(ghc->hva))
3310 		return -EFAULT;
3311 
3312 	if (unlikely(!ghc->memslot))
3313 		return kvm_read_guest(kvm, gpa, data, len);
3314 
3315 	r = __copy_from_user(data, (void __user *)ghc->hva + offset, len);
3316 	if (r)
3317 		return -EFAULT;
3318 
3319 	return 0;
3320 }
3321 EXPORT_SYMBOL_GPL(kvm_read_guest_offset_cached);
3322 
kvm_read_guest_cached(struct kvm * kvm,struct gfn_to_hva_cache * ghc,void * data,unsigned long len)3323 int kvm_read_guest_cached(struct kvm *kvm, struct gfn_to_hva_cache *ghc,
3324 			  void *data, unsigned long len)
3325 {
3326 	return kvm_read_guest_offset_cached(kvm, ghc, data, 0, len);
3327 }
3328 EXPORT_SYMBOL_GPL(kvm_read_guest_cached);
3329 
kvm_clear_guest(struct kvm * kvm,gpa_t gpa,unsigned long len)3330 int kvm_clear_guest(struct kvm *kvm, gpa_t gpa, unsigned long len)
3331 {
3332 	const void *zero_page = (const void *) __va(page_to_phys(ZERO_PAGE(0)));
3333 	gfn_t gfn = gpa >> PAGE_SHIFT;
3334 	int seg;
3335 	int offset = offset_in_page(gpa);
3336 	int ret;
3337 
3338 	while ((seg = next_segment(len, offset)) != 0) {
3339 		ret = kvm_write_guest_page(kvm, gfn, zero_page, offset, len);
3340 		if (ret < 0)
3341 			return ret;
3342 		offset = 0;
3343 		len -= seg;
3344 		++gfn;
3345 	}
3346 	return 0;
3347 }
3348 EXPORT_SYMBOL_GPL(kvm_clear_guest);
3349 
mark_page_dirty_in_slot(struct kvm * kvm,const struct kvm_memory_slot * memslot,gfn_t gfn)3350 void mark_page_dirty_in_slot(struct kvm *kvm,
3351 			     const struct kvm_memory_slot *memslot,
3352 		 	     gfn_t gfn)
3353 {
3354 	struct kvm_vcpu *vcpu = kvm_get_running_vcpu();
3355 
3356 #ifdef CONFIG_HAVE_KVM_DIRTY_RING
3357 	if (WARN_ON_ONCE(vcpu && vcpu->kvm != kvm))
3358 		return;
3359 
3360 	WARN_ON_ONCE(!vcpu && !kvm_arch_allow_write_without_running_vcpu(kvm));
3361 #endif
3362 
3363 	if (memslot && kvm_slot_dirty_track_enabled(memslot)) {
3364 		unsigned long rel_gfn = gfn - memslot->base_gfn;
3365 		u32 slot = (memslot->as_id << 16) | memslot->id;
3366 
3367 		if (kvm->dirty_ring_size && vcpu)
3368 			kvm_dirty_ring_push(vcpu, slot, rel_gfn);
3369 		else if (memslot->dirty_bitmap)
3370 			set_bit_le(rel_gfn, memslot->dirty_bitmap);
3371 	}
3372 }
3373 EXPORT_SYMBOL_GPL(mark_page_dirty_in_slot);
3374 
mark_page_dirty(struct kvm * kvm,gfn_t gfn)3375 void mark_page_dirty(struct kvm *kvm, gfn_t gfn)
3376 {
3377 	struct kvm_memory_slot *memslot;
3378 
3379 	memslot = gfn_to_memslot(kvm, gfn);
3380 	mark_page_dirty_in_slot(kvm, memslot, gfn);
3381 }
3382 EXPORT_SYMBOL_GPL(mark_page_dirty);
3383 
kvm_vcpu_mark_page_dirty(struct kvm_vcpu * vcpu,gfn_t gfn)3384 void kvm_vcpu_mark_page_dirty(struct kvm_vcpu *vcpu, gfn_t gfn)
3385 {
3386 	struct kvm_memory_slot *memslot;
3387 
3388 	memslot = kvm_vcpu_gfn_to_memslot(vcpu, gfn);
3389 	mark_page_dirty_in_slot(vcpu->kvm, memslot, gfn);
3390 }
3391 EXPORT_SYMBOL_GPL(kvm_vcpu_mark_page_dirty);
3392 
kvm_sigset_activate(struct kvm_vcpu * vcpu)3393 void kvm_sigset_activate(struct kvm_vcpu *vcpu)
3394 {
3395 	if (!vcpu->sigset_active)
3396 		return;
3397 
3398 	/*
3399 	 * This does a lockless modification of ->real_blocked, which is fine
3400 	 * because, only current can change ->real_blocked and all readers of
3401 	 * ->real_blocked don't care as long ->real_blocked is always a subset
3402 	 * of ->blocked.
3403 	 */
3404 	sigprocmask(SIG_SETMASK, &vcpu->sigset, &current->real_blocked);
3405 }
3406 
kvm_sigset_deactivate(struct kvm_vcpu * vcpu)3407 void kvm_sigset_deactivate(struct kvm_vcpu *vcpu)
3408 {
3409 	if (!vcpu->sigset_active)
3410 		return;
3411 
3412 	sigprocmask(SIG_SETMASK, &current->real_blocked, NULL);
3413 	sigemptyset(&current->real_blocked);
3414 }
3415 
grow_halt_poll_ns(struct kvm_vcpu * vcpu)3416 static void grow_halt_poll_ns(struct kvm_vcpu *vcpu)
3417 {
3418 	unsigned int old, val, grow, grow_start;
3419 
3420 	old = val = vcpu->halt_poll_ns;
3421 	grow_start = READ_ONCE(halt_poll_ns_grow_start);
3422 	grow = READ_ONCE(halt_poll_ns_grow);
3423 	if (!grow)
3424 		goto out;
3425 
3426 	val *= grow;
3427 	if (val < grow_start)
3428 		val = grow_start;
3429 
3430 	vcpu->halt_poll_ns = val;
3431 out:
3432 	trace_kvm_halt_poll_ns_grow(vcpu->vcpu_id, val, old);
3433 }
3434 
shrink_halt_poll_ns(struct kvm_vcpu * vcpu)3435 static void shrink_halt_poll_ns(struct kvm_vcpu *vcpu)
3436 {
3437 	unsigned int old, val, shrink, grow_start;
3438 
3439 	old = val = vcpu->halt_poll_ns;
3440 	shrink = READ_ONCE(halt_poll_ns_shrink);
3441 	grow_start = READ_ONCE(halt_poll_ns_grow_start);
3442 	if (shrink == 0)
3443 		val = 0;
3444 	else
3445 		val /= shrink;
3446 
3447 	if (val < grow_start)
3448 		val = 0;
3449 
3450 	vcpu->halt_poll_ns = val;
3451 	trace_kvm_halt_poll_ns_shrink(vcpu->vcpu_id, val, old);
3452 }
3453 
kvm_vcpu_check_block(struct kvm_vcpu * vcpu)3454 static int kvm_vcpu_check_block(struct kvm_vcpu *vcpu)
3455 {
3456 	int ret = -EINTR;
3457 	int idx = srcu_read_lock(&vcpu->kvm->srcu);
3458 
3459 	if (kvm_arch_vcpu_runnable(vcpu))
3460 		goto out;
3461 	if (kvm_cpu_has_pending_timer(vcpu))
3462 		goto out;
3463 	if (signal_pending(current))
3464 		goto out;
3465 	if (kvm_check_request(KVM_REQ_UNBLOCK, vcpu))
3466 		goto out;
3467 
3468 	ret = 0;
3469 out:
3470 	srcu_read_unlock(&vcpu->kvm->srcu, idx);
3471 	return ret;
3472 }
3473 
3474 /*
3475  * Block the vCPU until the vCPU is runnable, an event arrives, or a signal is
3476  * pending.  This is mostly used when halting a vCPU, but may also be used
3477  * directly for other vCPU non-runnable states, e.g. x86's Wait-For-SIPI.
3478  */
kvm_vcpu_block(struct kvm_vcpu * vcpu)3479 bool kvm_vcpu_block(struct kvm_vcpu *vcpu)
3480 {
3481 	struct rcuwait *wait = kvm_arch_vcpu_get_wait(vcpu);
3482 	bool waited = false;
3483 
3484 	vcpu->stat.generic.blocking = 1;
3485 
3486 	preempt_disable();
3487 	kvm_arch_vcpu_blocking(vcpu);
3488 	prepare_to_rcuwait(wait);
3489 	preempt_enable();
3490 
3491 	for (;;) {
3492 		set_current_state(TASK_INTERRUPTIBLE);
3493 
3494 		if (kvm_vcpu_check_block(vcpu) < 0)
3495 			break;
3496 
3497 		waited = true;
3498 		schedule();
3499 	}
3500 
3501 	preempt_disable();
3502 	finish_rcuwait(wait);
3503 	kvm_arch_vcpu_unblocking(vcpu);
3504 	preempt_enable();
3505 
3506 	vcpu->stat.generic.blocking = 0;
3507 
3508 	return waited;
3509 }
3510 
update_halt_poll_stats(struct kvm_vcpu * vcpu,ktime_t start,ktime_t end,bool success)3511 static inline void update_halt_poll_stats(struct kvm_vcpu *vcpu, ktime_t start,
3512 					  ktime_t end, bool success)
3513 {
3514 	struct kvm_vcpu_stat_generic *stats = &vcpu->stat.generic;
3515 	u64 poll_ns = ktime_to_ns(ktime_sub(end, start));
3516 
3517 	++vcpu->stat.generic.halt_attempted_poll;
3518 
3519 	if (success) {
3520 		++vcpu->stat.generic.halt_successful_poll;
3521 
3522 		if (!vcpu_valid_wakeup(vcpu))
3523 			++vcpu->stat.generic.halt_poll_invalid;
3524 
3525 		stats->halt_poll_success_ns += poll_ns;
3526 		KVM_STATS_LOG_HIST_UPDATE(stats->halt_poll_success_hist, poll_ns);
3527 	} else {
3528 		stats->halt_poll_fail_ns += poll_ns;
3529 		KVM_STATS_LOG_HIST_UPDATE(stats->halt_poll_fail_hist, poll_ns);
3530 	}
3531 }
3532 
kvm_vcpu_max_halt_poll_ns(struct kvm_vcpu * vcpu)3533 static unsigned int kvm_vcpu_max_halt_poll_ns(struct kvm_vcpu *vcpu)
3534 {
3535 	struct kvm *kvm = vcpu->kvm;
3536 
3537 	if (kvm->override_halt_poll_ns) {
3538 		/*
3539 		 * Ensure kvm->max_halt_poll_ns is not read before
3540 		 * kvm->override_halt_poll_ns.
3541 		 *
3542 		 * Pairs with the smp_wmb() when enabling KVM_CAP_HALT_POLL.
3543 		 */
3544 		smp_rmb();
3545 		return READ_ONCE(kvm->max_halt_poll_ns);
3546 	}
3547 
3548 	return READ_ONCE(halt_poll_ns);
3549 }
3550 
3551 /*
3552  * Emulate a vCPU halt condition, e.g. HLT on x86, WFI on arm, etc...  If halt
3553  * polling is enabled, busy wait for a short time before blocking to avoid the
3554  * expensive block+unblock sequence if a wake event arrives soon after the vCPU
3555  * is halted.
3556  */
kvm_vcpu_halt(struct kvm_vcpu * vcpu)3557 void kvm_vcpu_halt(struct kvm_vcpu *vcpu)
3558 {
3559 	unsigned int max_halt_poll_ns = kvm_vcpu_max_halt_poll_ns(vcpu);
3560 	bool halt_poll_allowed = !kvm_arch_no_poll(vcpu);
3561 	ktime_t start, cur, poll_end;
3562 	bool waited = false;
3563 	bool do_halt_poll;
3564 	u64 halt_ns;
3565 
3566 	if (vcpu->halt_poll_ns > max_halt_poll_ns)
3567 		vcpu->halt_poll_ns = max_halt_poll_ns;
3568 
3569 	do_halt_poll = halt_poll_allowed && vcpu->halt_poll_ns;
3570 
3571 	start = cur = poll_end = ktime_get();
3572 	if (do_halt_poll) {
3573 		ktime_t stop = ktime_add_ns(start, vcpu->halt_poll_ns);
3574 
3575 		do {
3576 			if (kvm_vcpu_check_block(vcpu) < 0)
3577 				goto out;
3578 			cpu_relax();
3579 			poll_end = cur = ktime_get();
3580 		} while (kvm_vcpu_can_poll(cur, stop));
3581 	}
3582 
3583 	waited = kvm_vcpu_block(vcpu);
3584 
3585 	cur = ktime_get();
3586 	if (waited) {
3587 		vcpu->stat.generic.halt_wait_ns +=
3588 			ktime_to_ns(cur) - ktime_to_ns(poll_end);
3589 		KVM_STATS_LOG_HIST_UPDATE(vcpu->stat.generic.halt_wait_hist,
3590 				ktime_to_ns(cur) - ktime_to_ns(poll_end));
3591 	}
3592 out:
3593 	/* The total time the vCPU was "halted", including polling time. */
3594 	halt_ns = ktime_to_ns(cur) - ktime_to_ns(start);
3595 
3596 	/*
3597 	 * Note, halt-polling is considered successful so long as the vCPU was
3598 	 * never actually scheduled out, i.e. even if the wake event arrived
3599 	 * after of the halt-polling loop itself, but before the full wait.
3600 	 */
3601 	if (do_halt_poll)
3602 		update_halt_poll_stats(vcpu, start, poll_end, !waited);
3603 
3604 	if (halt_poll_allowed) {
3605 		/* Recompute the max halt poll time in case it changed. */
3606 		max_halt_poll_ns = kvm_vcpu_max_halt_poll_ns(vcpu);
3607 
3608 		if (!vcpu_valid_wakeup(vcpu)) {
3609 			shrink_halt_poll_ns(vcpu);
3610 		} else if (max_halt_poll_ns) {
3611 			if (halt_ns <= vcpu->halt_poll_ns)
3612 				;
3613 			/* we had a long block, shrink polling */
3614 			else if (vcpu->halt_poll_ns &&
3615 				 halt_ns > max_halt_poll_ns)
3616 				shrink_halt_poll_ns(vcpu);
3617 			/* we had a short halt and our poll time is too small */
3618 			else if (vcpu->halt_poll_ns < max_halt_poll_ns &&
3619 				 halt_ns < max_halt_poll_ns)
3620 				grow_halt_poll_ns(vcpu);
3621 		} else {
3622 			vcpu->halt_poll_ns = 0;
3623 		}
3624 	}
3625 
3626 	trace_kvm_vcpu_wakeup(halt_ns, waited, vcpu_valid_wakeup(vcpu));
3627 }
3628 EXPORT_SYMBOL_GPL(kvm_vcpu_halt);
3629 
kvm_vcpu_wake_up(struct kvm_vcpu * vcpu)3630 bool kvm_vcpu_wake_up(struct kvm_vcpu *vcpu)
3631 {
3632 	if (__kvm_vcpu_wake_up(vcpu)) {
3633 		WRITE_ONCE(vcpu->ready, true);
3634 		++vcpu->stat.generic.halt_wakeup;
3635 		return true;
3636 	}
3637 
3638 	return false;
3639 }
3640 EXPORT_SYMBOL_GPL(kvm_vcpu_wake_up);
3641 
3642 #ifndef CONFIG_S390
3643 /*
3644  * Kick a sleeping VCPU, or a guest VCPU in guest mode, into host kernel mode.
3645  */
kvm_vcpu_kick(struct kvm_vcpu * vcpu)3646 void kvm_vcpu_kick(struct kvm_vcpu *vcpu)
3647 {
3648 	int me, cpu;
3649 
3650 	if (kvm_vcpu_wake_up(vcpu))
3651 		return;
3652 
3653 	me = get_cpu();
3654 	/*
3655 	 * The only state change done outside the vcpu mutex is IN_GUEST_MODE
3656 	 * to EXITING_GUEST_MODE.  Therefore the moderately expensive "should
3657 	 * kick" check does not need atomic operations if kvm_vcpu_kick is used
3658 	 * within the vCPU thread itself.
3659 	 */
3660 	if (vcpu == __this_cpu_read(kvm_running_vcpu)) {
3661 		if (vcpu->mode == IN_GUEST_MODE)
3662 			WRITE_ONCE(vcpu->mode, EXITING_GUEST_MODE);
3663 		goto out;
3664 	}
3665 
3666 	/*
3667 	 * Note, the vCPU could get migrated to a different pCPU at any point
3668 	 * after kvm_arch_vcpu_should_kick(), which could result in sending an
3669 	 * IPI to the previous pCPU.  But, that's ok because the purpose of the
3670 	 * IPI is to force the vCPU to leave IN_GUEST_MODE, and migrating the
3671 	 * vCPU also requires it to leave IN_GUEST_MODE.
3672 	 */
3673 	if (kvm_arch_vcpu_should_kick(vcpu)) {
3674 		cpu = READ_ONCE(vcpu->cpu);
3675 		if (cpu != me && (unsigned)cpu < nr_cpu_ids && cpu_online(cpu))
3676 			smp_send_reschedule(cpu);
3677 	}
3678 out:
3679 	put_cpu();
3680 }
3681 EXPORT_SYMBOL_GPL(kvm_vcpu_kick);
3682 #endif /* !CONFIG_S390 */
3683 
kvm_vcpu_yield_to(struct kvm_vcpu * target)3684 int kvm_vcpu_yield_to(struct kvm_vcpu *target)
3685 {
3686 	struct pid *pid;
3687 	struct task_struct *task = NULL;
3688 	int ret = 0;
3689 
3690 	rcu_read_lock();
3691 	pid = rcu_dereference(target->pid);
3692 	if (pid)
3693 		task = get_pid_task(pid, PIDTYPE_PID);
3694 	rcu_read_unlock();
3695 	if (!task)
3696 		return ret;
3697 	ret = yield_to(task, 1);
3698 	put_task_struct(task);
3699 
3700 	return ret;
3701 }
3702 EXPORT_SYMBOL_GPL(kvm_vcpu_yield_to);
3703 
3704 /*
3705  * Helper that checks whether a VCPU is eligible for directed yield.
3706  * Most eligible candidate to yield is decided by following heuristics:
3707  *
3708  *  (a) VCPU which has not done pl-exit or cpu relax intercepted recently
3709  *  (preempted lock holder), indicated by @in_spin_loop.
3710  *  Set at the beginning and cleared at the end of interception/PLE handler.
3711  *
3712  *  (b) VCPU which has done pl-exit/ cpu relax intercepted but did not get
3713  *  chance last time (mostly it has become eligible now since we have probably
3714  *  yielded to lockholder in last iteration. This is done by toggling
3715  *  @dy_eligible each time a VCPU checked for eligibility.)
3716  *
3717  *  Yielding to a recently pl-exited/cpu relax intercepted VCPU before yielding
3718  *  to preempted lock-holder could result in wrong VCPU selection and CPU
3719  *  burning. Giving priority for a potential lock-holder increases lock
3720  *  progress.
3721  *
3722  *  Since algorithm is based on heuristics, accessing another VCPU data without
3723  *  locking does not harm. It may result in trying to yield to  same VCPU, fail
3724  *  and continue with next VCPU and so on.
3725  */
kvm_vcpu_eligible_for_directed_yield(struct kvm_vcpu * vcpu)3726 static bool kvm_vcpu_eligible_for_directed_yield(struct kvm_vcpu *vcpu)
3727 {
3728 #ifdef CONFIG_HAVE_KVM_CPU_RELAX_INTERCEPT
3729 	bool eligible;
3730 
3731 	eligible = !vcpu->spin_loop.in_spin_loop ||
3732 		    vcpu->spin_loop.dy_eligible;
3733 
3734 	if (vcpu->spin_loop.in_spin_loop)
3735 		kvm_vcpu_set_dy_eligible(vcpu, !vcpu->spin_loop.dy_eligible);
3736 
3737 	return eligible;
3738 #else
3739 	return true;
3740 #endif
3741 }
3742 
3743 /*
3744  * Unlike kvm_arch_vcpu_runnable, this function is called outside
3745  * a vcpu_load/vcpu_put pair.  However, for most architectures
3746  * kvm_arch_vcpu_runnable does not require vcpu_load.
3747  */
kvm_arch_dy_runnable(struct kvm_vcpu * vcpu)3748 bool __weak kvm_arch_dy_runnable(struct kvm_vcpu *vcpu)
3749 {
3750 	return kvm_arch_vcpu_runnable(vcpu);
3751 }
3752 
vcpu_dy_runnable(struct kvm_vcpu * vcpu)3753 static bool vcpu_dy_runnable(struct kvm_vcpu *vcpu)
3754 {
3755 	if (kvm_arch_dy_runnable(vcpu))
3756 		return true;
3757 
3758 #ifdef CONFIG_KVM_ASYNC_PF
3759 	if (!list_empty_careful(&vcpu->async_pf.done))
3760 		return true;
3761 #endif
3762 
3763 	return false;
3764 }
3765 
kvm_arch_dy_has_pending_interrupt(struct kvm_vcpu * vcpu)3766 bool __weak kvm_arch_dy_has_pending_interrupt(struct kvm_vcpu *vcpu)
3767 {
3768 	return false;
3769 }
3770 
kvm_vcpu_on_spin(struct kvm_vcpu * me,bool yield_to_kernel_mode)3771 void kvm_vcpu_on_spin(struct kvm_vcpu *me, bool yield_to_kernel_mode)
3772 {
3773 	struct kvm *kvm = me->kvm;
3774 	struct kvm_vcpu *vcpu;
3775 	int last_boosted_vcpu = me->kvm->last_boosted_vcpu;
3776 	unsigned long i;
3777 	int yielded = 0;
3778 	int try = 3;
3779 	int pass;
3780 
3781 	kvm_vcpu_set_in_spin_loop(me, true);
3782 	/*
3783 	 * We boost the priority of a VCPU that is runnable but not
3784 	 * currently running, because it got preempted by something
3785 	 * else and called schedule in __vcpu_run.  Hopefully that
3786 	 * VCPU is holding the lock that we need and will release it.
3787 	 * We approximate round-robin by starting at the last boosted VCPU.
3788 	 */
3789 	for (pass = 0; pass < 2 && !yielded && try; pass++) {
3790 		kvm_for_each_vcpu(i, vcpu, kvm) {
3791 			if (!pass && i <= last_boosted_vcpu) {
3792 				i = last_boosted_vcpu;
3793 				continue;
3794 			} else if (pass && i > last_boosted_vcpu)
3795 				break;
3796 			if (!READ_ONCE(vcpu->ready))
3797 				continue;
3798 			if (vcpu == me)
3799 				continue;
3800 			if (kvm_vcpu_is_blocking(vcpu) && !vcpu_dy_runnable(vcpu))
3801 				continue;
3802 			if (READ_ONCE(vcpu->preempted) && yield_to_kernel_mode &&
3803 			    !kvm_arch_dy_has_pending_interrupt(vcpu) &&
3804 			    !kvm_arch_vcpu_in_kernel(vcpu))
3805 				continue;
3806 			if (!kvm_vcpu_eligible_for_directed_yield(vcpu))
3807 				continue;
3808 
3809 			yielded = kvm_vcpu_yield_to(vcpu);
3810 			if (yielded > 0) {
3811 				kvm->last_boosted_vcpu = i;
3812 				break;
3813 			} else if (yielded < 0) {
3814 				try--;
3815 				if (!try)
3816 					break;
3817 			}
3818 		}
3819 	}
3820 	kvm_vcpu_set_in_spin_loop(me, false);
3821 
3822 	/* Ensure vcpu is not eligible during next spinloop */
3823 	kvm_vcpu_set_dy_eligible(me, false);
3824 }
3825 EXPORT_SYMBOL_GPL(kvm_vcpu_on_spin);
3826 
kvm_page_in_dirty_ring(struct kvm * kvm,unsigned long pgoff)3827 static bool kvm_page_in_dirty_ring(struct kvm *kvm, unsigned long pgoff)
3828 {
3829 #ifdef CONFIG_HAVE_KVM_DIRTY_RING
3830 	return (pgoff >= KVM_DIRTY_LOG_PAGE_OFFSET) &&
3831 	    (pgoff < KVM_DIRTY_LOG_PAGE_OFFSET +
3832 	     kvm->dirty_ring_size / PAGE_SIZE);
3833 #else
3834 	return false;
3835 #endif
3836 }
3837 
kvm_vcpu_fault(struct vm_fault * vmf)3838 static vm_fault_t kvm_vcpu_fault(struct vm_fault *vmf)
3839 {
3840 	struct kvm_vcpu *vcpu = vmf->vma->vm_file->private_data;
3841 	struct page *page;
3842 
3843 	if (vmf->pgoff == 0)
3844 		page = virt_to_page(vcpu->run);
3845 #ifdef CONFIG_X86
3846 	else if (vmf->pgoff == KVM_PIO_PAGE_OFFSET)
3847 		page = virt_to_page(vcpu->arch.pio_data);
3848 #endif
3849 #ifdef CONFIG_KVM_MMIO
3850 	else if (vmf->pgoff == KVM_COALESCED_MMIO_PAGE_OFFSET)
3851 		page = virt_to_page(vcpu->kvm->coalesced_mmio_ring);
3852 #endif
3853 	else if (kvm_page_in_dirty_ring(vcpu->kvm, vmf->pgoff))
3854 		page = kvm_dirty_ring_get_page(
3855 		    &vcpu->dirty_ring,
3856 		    vmf->pgoff - KVM_DIRTY_LOG_PAGE_OFFSET);
3857 	else
3858 		return kvm_arch_vcpu_fault(vcpu, vmf);
3859 	get_page(page);
3860 	vmf->page = page;
3861 	return 0;
3862 }
3863 
3864 static const struct vm_operations_struct kvm_vcpu_vm_ops = {
3865 	.fault = kvm_vcpu_fault,
3866 };
3867 
kvm_vcpu_mmap(struct file * file,struct vm_area_struct * vma)3868 static int kvm_vcpu_mmap(struct file *file, struct vm_area_struct *vma)
3869 {
3870 	struct kvm_vcpu *vcpu = file->private_data;
3871 	unsigned long pages = vma_pages(vma);
3872 
3873 	if ((kvm_page_in_dirty_ring(vcpu->kvm, vma->vm_pgoff) ||
3874 	     kvm_page_in_dirty_ring(vcpu->kvm, vma->vm_pgoff + pages - 1)) &&
3875 	    ((vma->vm_flags & VM_EXEC) || !(vma->vm_flags & VM_SHARED)))
3876 		return -EINVAL;
3877 
3878 	vma->vm_ops = &kvm_vcpu_vm_ops;
3879 	return 0;
3880 }
3881 
kvm_vcpu_release(struct inode * inode,struct file * filp)3882 static int kvm_vcpu_release(struct inode *inode, struct file *filp)
3883 {
3884 	struct kvm_vcpu *vcpu = filp->private_data;
3885 
3886 	kvm_put_kvm(vcpu->kvm);
3887 	return 0;
3888 }
3889 
3890 static const struct file_operations kvm_vcpu_fops = {
3891 	.release        = kvm_vcpu_release,
3892 	.unlocked_ioctl = kvm_vcpu_ioctl,
3893 	.mmap           = kvm_vcpu_mmap,
3894 	.llseek		= noop_llseek,
3895 	KVM_COMPAT(kvm_vcpu_compat_ioctl),
3896 };
3897 
3898 /*
3899  * Allocates an inode for the vcpu.
3900  */
create_vcpu_fd(struct kvm_vcpu * vcpu)3901 static int create_vcpu_fd(struct kvm_vcpu *vcpu)
3902 {
3903 	char name[8 + 1 + ITOA_MAX_LEN + 1];
3904 
3905 	snprintf(name, sizeof(name), "kvm-vcpu:%d", vcpu->vcpu_id);
3906 	return anon_inode_getfd(name, &kvm_vcpu_fops, vcpu, O_RDWR | O_CLOEXEC);
3907 }
3908 
3909 #ifdef __KVM_HAVE_ARCH_VCPU_DEBUGFS
vcpu_get_pid(void * data,u64 * val)3910 static int vcpu_get_pid(void *data, u64 *val)
3911 {
3912 	struct kvm_vcpu *vcpu = data;
3913 
3914 	rcu_read_lock();
3915 	*val = pid_nr(rcu_dereference(vcpu->pid));
3916 	rcu_read_unlock();
3917 	return 0;
3918 }
3919 
3920 DEFINE_SIMPLE_ATTRIBUTE(vcpu_get_pid_fops, vcpu_get_pid, NULL, "%llu\n");
3921 
kvm_create_vcpu_debugfs(struct kvm_vcpu * vcpu)3922 static void kvm_create_vcpu_debugfs(struct kvm_vcpu *vcpu)
3923 {
3924 	struct dentry *debugfs_dentry;
3925 	char dir_name[ITOA_MAX_LEN * 2];
3926 
3927 	if (!debugfs_initialized())
3928 		return;
3929 
3930 	snprintf(dir_name, sizeof(dir_name), "vcpu%d", vcpu->vcpu_id);
3931 	debugfs_dentry = debugfs_create_dir(dir_name,
3932 					    vcpu->kvm->debugfs_dentry);
3933 	debugfs_create_file("pid", 0444, debugfs_dentry, vcpu,
3934 			    &vcpu_get_pid_fops);
3935 
3936 	kvm_arch_create_vcpu_debugfs(vcpu, debugfs_dentry);
3937 }
3938 #endif
3939 
3940 /*
3941  * Creates some virtual cpus.  Good luck creating more than one.
3942  */
kvm_vm_ioctl_create_vcpu(struct kvm * kvm,u32 id)3943 static int kvm_vm_ioctl_create_vcpu(struct kvm *kvm, u32 id)
3944 {
3945 	int r;
3946 	struct kvm_vcpu *vcpu;
3947 	struct page *page;
3948 
3949 	if (id >= KVM_MAX_VCPU_IDS)
3950 		return -EINVAL;
3951 
3952 	mutex_lock(&kvm->lock);
3953 	if (kvm->created_vcpus >= kvm->max_vcpus) {
3954 		mutex_unlock(&kvm->lock);
3955 		return -EINVAL;
3956 	}
3957 
3958 	r = kvm_arch_vcpu_precreate(kvm, id);
3959 	if (r) {
3960 		mutex_unlock(&kvm->lock);
3961 		return r;
3962 	}
3963 
3964 	kvm->created_vcpus++;
3965 	mutex_unlock(&kvm->lock);
3966 
3967 	vcpu = kmem_cache_zalloc(kvm_vcpu_cache, GFP_KERNEL_ACCOUNT);
3968 	if (!vcpu) {
3969 		r = -ENOMEM;
3970 		goto vcpu_decrement;
3971 	}
3972 
3973 	BUILD_BUG_ON(sizeof(struct kvm_run) > PAGE_SIZE);
3974 	page = alloc_page(GFP_KERNEL_ACCOUNT | __GFP_ZERO);
3975 	if (!page) {
3976 		r = -ENOMEM;
3977 		goto vcpu_free;
3978 	}
3979 	vcpu->run = page_address(page);
3980 
3981 	kvm_vcpu_init(vcpu, kvm, id);
3982 
3983 	r = kvm_arch_vcpu_create(vcpu);
3984 	if (r)
3985 		goto vcpu_free_run_page;
3986 
3987 	if (kvm->dirty_ring_size) {
3988 		r = kvm_dirty_ring_alloc(&vcpu->dirty_ring,
3989 					 id, kvm->dirty_ring_size);
3990 		if (r)
3991 			goto arch_vcpu_destroy;
3992 	}
3993 
3994 	mutex_lock(&kvm->lock);
3995 
3996 #ifdef CONFIG_LOCKDEP
3997 	/* Ensure that lockdep knows vcpu->mutex is taken *inside* kvm->lock */
3998 	mutex_lock(&vcpu->mutex);
3999 	mutex_unlock(&vcpu->mutex);
4000 #endif
4001 
4002 	if (kvm_get_vcpu_by_id(kvm, id)) {
4003 		r = -EEXIST;
4004 		goto unlock_vcpu_destroy;
4005 	}
4006 
4007 	vcpu->vcpu_idx = atomic_read(&kvm->online_vcpus);
4008 	r = xa_reserve(&kvm->vcpu_array, vcpu->vcpu_idx, GFP_KERNEL_ACCOUNT);
4009 	if (r)
4010 		goto unlock_vcpu_destroy;
4011 
4012 	/* Now it's all set up, let userspace reach it */
4013 	kvm_get_kvm(kvm);
4014 	r = create_vcpu_fd(vcpu);
4015 	if (r < 0)
4016 		goto kvm_put_xa_release;
4017 
4018 	if (KVM_BUG_ON(xa_store(&kvm->vcpu_array, vcpu->vcpu_idx, vcpu, 0), kvm)) {
4019 		r = -EINVAL;
4020 		goto kvm_put_xa_release;
4021 	}
4022 
4023 	/*
4024 	 * Pairs with smp_rmb() in kvm_get_vcpu.  Store the vcpu
4025 	 * pointer before kvm->online_vcpu's incremented value.
4026 	 */
4027 	smp_wmb();
4028 	atomic_inc(&kvm->online_vcpus);
4029 
4030 	mutex_unlock(&kvm->lock);
4031 	kvm_arch_vcpu_postcreate(vcpu);
4032 	kvm_create_vcpu_debugfs(vcpu);
4033 	return r;
4034 
4035 kvm_put_xa_release:
4036 	kvm_put_kvm_no_destroy(kvm);
4037 	xa_release(&kvm->vcpu_array, vcpu->vcpu_idx);
4038 unlock_vcpu_destroy:
4039 	mutex_unlock(&kvm->lock);
4040 	kvm_dirty_ring_free(&vcpu->dirty_ring);
4041 arch_vcpu_destroy:
4042 	kvm_arch_vcpu_destroy(vcpu);
4043 vcpu_free_run_page:
4044 	free_page((unsigned long)vcpu->run);
4045 vcpu_free:
4046 	kmem_cache_free(kvm_vcpu_cache, vcpu);
4047 vcpu_decrement:
4048 	mutex_lock(&kvm->lock);
4049 	kvm->created_vcpus--;
4050 	mutex_unlock(&kvm->lock);
4051 	return r;
4052 }
4053 
kvm_vcpu_ioctl_set_sigmask(struct kvm_vcpu * vcpu,sigset_t * sigset)4054 static int kvm_vcpu_ioctl_set_sigmask(struct kvm_vcpu *vcpu, sigset_t *sigset)
4055 {
4056 	if (sigset) {
4057 		sigdelsetmask(sigset, sigmask(SIGKILL)|sigmask(SIGSTOP));
4058 		vcpu->sigset_active = 1;
4059 		vcpu->sigset = *sigset;
4060 	} else
4061 		vcpu->sigset_active = 0;
4062 	return 0;
4063 }
4064 
kvm_vcpu_stats_read(struct file * file,char __user * user_buffer,size_t size,loff_t * offset)4065 static ssize_t kvm_vcpu_stats_read(struct file *file, char __user *user_buffer,
4066 			      size_t size, loff_t *offset)
4067 {
4068 	struct kvm_vcpu *vcpu = file->private_data;
4069 
4070 	return kvm_stats_read(vcpu->stats_id, &kvm_vcpu_stats_header,
4071 			&kvm_vcpu_stats_desc[0], &vcpu->stat,
4072 			sizeof(vcpu->stat), user_buffer, size, offset);
4073 }
4074 
kvm_vcpu_stats_release(struct inode * inode,struct file * file)4075 static int kvm_vcpu_stats_release(struct inode *inode, struct file *file)
4076 {
4077 	struct kvm_vcpu *vcpu = file->private_data;
4078 
4079 	kvm_put_kvm(vcpu->kvm);
4080 	return 0;
4081 }
4082 
4083 static const struct file_operations kvm_vcpu_stats_fops = {
4084 	.read = kvm_vcpu_stats_read,
4085 	.release = kvm_vcpu_stats_release,
4086 	.llseek = noop_llseek,
4087 };
4088 
kvm_vcpu_ioctl_get_stats_fd(struct kvm_vcpu * vcpu)4089 static int kvm_vcpu_ioctl_get_stats_fd(struct kvm_vcpu *vcpu)
4090 {
4091 	int fd;
4092 	struct file *file;
4093 	char name[15 + ITOA_MAX_LEN + 1];
4094 
4095 	snprintf(name, sizeof(name), "kvm-vcpu-stats:%d", vcpu->vcpu_id);
4096 
4097 	fd = get_unused_fd_flags(O_CLOEXEC);
4098 	if (fd < 0)
4099 		return fd;
4100 
4101 	file = anon_inode_getfile(name, &kvm_vcpu_stats_fops, vcpu, O_RDONLY);
4102 	if (IS_ERR(file)) {
4103 		put_unused_fd(fd);
4104 		return PTR_ERR(file);
4105 	}
4106 
4107 	kvm_get_kvm(vcpu->kvm);
4108 
4109 	file->f_mode |= FMODE_PREAD;
4110 	fd_install(fd, file);
4111 
4112 	return fd;
4113 }
4114 
kvm_vcpu_ioctl(struct file * filp,unsigned int ioctl,unsigned long arg)4115 static long kvm_vcpu_ioctl(struct file *filp,
4116 			   unsigned int ioctl, unsigned long arg)
4117 {
4118 	struct kvm_vcpu *vcpu = filp->private_data;
4119 	void __user *argp = (void __user *)arg;
4120 	int r;
4121 	struct kvm_fpu *fpu = NULL;
4122 	struct kvm_sregs *kvm_sregs = NULL;
4123 
4124 	if (vcpu->kvm->mm != current->mm || vcpu->kvm->vm_dead)
4125 		return -EIO;
4126 
4127 	if (unlikely(_IOC_TYPE(ioctl) != KVMIO))
4128 		return -EINVAL;
4129 
4130 	/*
4131 	 * Some architectures have vcpu ioctls that are asynchronous to vcpu
4132 	 * execution; mutex_lock() would break them.
4133 	 */
4134 	r = kvm_arch_vcpu_async_ioctl(filp, ioctl, arg);
4135 	if (r != -ENOIOCTLCMD)
4136 		return r;
4137 
4138 	if (mutex_lock_killable(&vcpu->mutex))
4139 		return -EINTR;
4140 	switch (ioctl) {
4141 	case KVM_RUN: {
4142 		struct pid *oldpid;
4143 		r = -EINVAL;
4144 		if (arg)
4145 			goto out;
4146 		oldpid = rcu_access_pointer(vcpu->pid);
4147 		if (unlikely(oldpid != task_pid(current))) {
4148 			/* The thread running this VCPU changed. */
4149 			struct pid *newpid;
4150 
4151 			r = kvm_arch_vcpu_run_pid_change(vcpu);
4152 			if (r)
4153 				break;
4154 
4155 			newpid = get_task_pid(current, PIDTYPE_PID);
4156 			rcu_assign_pointer(vcpu->pid, newpid);
4157 			if (oldpid)
4158 				synchronize_rcu();
4159 			put_pid(oldpid);
4160 		}
4161 		r = kvm_arch_vcpu_ioctl_run(vcpu);
4162 		trace_kvm_userspace_exit(vcpu->run->exit_reason, r);
4163 		break;
4164 	}
4165 	case KVM_GET_REGS: {
4166 		struct kvm_regs *kvm_regs;
4167 
4168 		r = -ENOMEM;
4169 		kvm_regs = kzalloc(sizeof(struct kvm_regs), GFP_KERNEL_ACCOUNT);
4170 		if (!kvm_regs)
4171 			goto out;
4172 		r = kvm_arch_vcpu_ioctl_get_regs(vcpu, kvm_regs);
4173 		if (r)
4174 			goto out_free1;
4175 		r = -EFAULT;
4176 		if (copy_to_user(argp, kvm_regs, sizeof(struct kvm_regs)))
4177 			goto out_free1;
4178 		r = 0;
4179 out_free1:
4180 		kfree(kvm_regs);
4181 		break;
4182 	}
4183 	case KVM_SET_REGS: {
4184 		struct kvm_regs *kvm_regs;
4185 
4186 		kvm_regs = memdup_user(argp, sizeof(*kvm_regs));
4187 		if (IS_ERR(kvm_regs)) {
4188 			r = PTR_ERR(kvm_regs);
4189 			goto out;
4190 		}
4191 		r = kvm_arch_vcpu_ioctl_set_regs(vcpu, kvm_regs);
4192 		kfree(kvm_regs);
4193 		break;
4194 	}
4195 	case KVM_GET_SREGS: {
4196 		kvm_sregs = kzalloc(sizeof(struct kvm_sregs),
4197 				    GFP_KERNEL_ACCOUNT);
4198 		r = -ENOMEM;
4199 		if (!kvm_sregs)
4200 			goto out;
4201 		r = kvm_arch_vcpu_ioctl_get_sregs(vcpu, kvm_sregs);
4202 		if (r)
4203 			goto out;
4204 		r = -EFAULT;
4205 		if (copy_to_user(argp, kvm_sregs, sizeof(struct kvm_sregs)))
4206 			goto out;
4207 		r = 0;
4208 		break;
4209 	}
4210 	case KVM_SET_SREGS: {
4211 		kvm_sregs = memdup_user(argp, sizeof(*kvm_sregs));
4212 		if (IS_ERR(kvm_sregs)) {
4213 			r = PTR_ERR(kvm_sregs);
4214 			kvm_sregs = NULL;
4215 			goto out;
4216 		}
4217 		r = kvm_arch_vcpu_ioctl_set_sregs(vcpu, kvm_sregs);
4218 		break;
4219 	}
4220 	case KVM_GET_MP_STATE: {
4221 		struct kvm_mp_state mp_state;
4222 
4223 		r = kvm_arch_vcpu_ioctl_get_mpstate(vcpu, &mp_state);
4224 		if (r)
4225 			goto out;
4226 		r = -EFAULT;
4227 		if (copy_to_user(argp, &mp_state, sizeof(mp_state)))
4228 			goto out;
4229 		r = 0;
4230 		break;
4231 	}
4232 	case KVM_SET_MP_STATE: {
4233 		struct kvm_mp_state mp_state;
4234 
4235 		r = -EFAULT;
4236 		if (copy_from_user(&mp_state, argp, sizeof(mp_state)))
4237 			goto out;
4238 		r = kvm_arch_vcpu_ioctl_set_mpstate(vcpu, &mp_state);
4239 		break;
4240 	}
4241 	case KVM_TRANSLATE: {
4242 		struct kvm_translation tr;
4243 
4244 		r = -EFAULT;
4245 		if (copy_from_user(&tr, argp, sizeof(tr)))
4246 			goto out;
4247 		r = kvm_arch_vcpu_ioctl_translate(vcpu, &tr);
4248 		if (r)
4249 			goto out;
4250 		r = -EFAULT;
4251 		if (copy_to_user(argp, &tr, sizeof(tr)))
4252 			goto out;
4253 		r = 0;
4254 		break;
4255 	}
4256 	case KVM_SET_GUEST_DEBUG: {
4257 		struct kvm_guest_debug dbg;
4258 
4259 		r = -EFAULT;
4260 		if (copy_from_user(&dbg, argp, sizeof(dbg)))
4261 			goto out;
4262 		r = kvm_arch_vcpu_ioctl_set_guest_debug(vcpu, &dbg);
4263 		break;
4264 	}
4265 	case KVM_SET_SIGNAL_MASK: {
4266 		struct kvm_signal_mask __user *sigmask_arg = argp;
4267 		struct kvm_signal_mask kvm_sigmask;
4268 		sigset_t sigset, *p;
4269 
4270 		p = NULL;
4271 		if (argp) {
4272 			r = -EFAULT;
4273 			if (copy_from_user(&kvm_sigmask, argp,
4274 					   sizeof(kvm_sigmask)))
4275 				goto out;
4276 			r = -EINVAL;
4277 			if (kvm_sigmask.len != sizeof(sigset))
4278 				goto out;
4279 			r = -EFAULT;
4280 			if (copy_from_user(&sigset, sigmask_arg->sigset,
4281 					   sizeof(sigset)))
4282 				goto out;
4283 			p = &sigset;
4284 		}
4285 		r = kvm_vcpu_ioctl_set_sigmask(vcpu, p);
4286 		break;
4287 	}
4288 	case KVM_GET_FPU: {
4289 		fpu = kzalloc(sizeof(struct kvm_fpu), GFP_KERNEL_ACCOUNT);
4290 		r = -ENOMEM;
4291 		if (!fpu)
4292 			goto out;
4293 		r = kvm_arch_vcpu_ioctl_get_fpu(vcpu, fpu);
4294 		if (r)
4295 			goto out;
4296 		r = -EFAULT;
4297 		if (copy_to_user(argp, fpu, sizeof(struct kvm_fpu)))
4298 			goto out;
4299 		r = 0;
4300 		break;
4301 	}
4302 	case KVM_SET_FPU: {
4303 		fpu = memdup_user(argp, sizeof(*fpu));
4304 		if (IS_ERR(fpu)) {
4305 			r = PTR_ERR(fpu);
4306 			fpu = NULL;
4307 			goto out;
4308 		}
4309 		r = kvm_arch_vcpu_ioctl_set_fpu(vcpu, fpu);
4310 		break;
4311 	}
4312 	case KVM_GET_STATS_FD: {
4313 		r = kvm_vcpu_ioctl_get_stats_fd(vcpu);
4314 		break;
4315 	}
4316 	default:
4317 		r = kvm_arch_vcpu_ioctl(filp, ioctl, arg);
4318 	}
4319 out:
4320 	mutex_unlock(&vcpu->mutex);
4321 	kfree(fpu);
4322 	kfree(kvm_sregs);
4323 	return r;
4324 }
4325 
4326 #ifdef CONFIG_KVM_COMPAT
kvm_vcpu_compat_ioctl(struct file * filp,unsigned int ioctl,unsigned long arg)4327 static long kvm_vcpu_compat_ioctl(struct file *filp,
4328 				  unsigned int ioctl, unsigned long arg)
4329 {
4330 	struct kvm_vcpu *vcpu = filp->private_data;
4331 	void __user *argp = compat_ptr(arg);
4332 	int r;
4333 
4334 	if (vcpu->kvm->mm != current->mm || vcpu->kvm->vm_dead)
4335 		return -EIO;
4336 
4337 	switch (ioctl) {
4338 	case KVM_SET_SIGNAL_MASK: {
4339 		struct kvm_signal_mask __user *sigmask_arg = argp;
4340 		struct kvm_signal_mask kvm_sigmask;
4341 		sigset_t sigset;
4342 
4343 		if (argp) {
4344 			r = -EFAULT;
4345 			if (copy_from_user(&kvm_sigmask, argp,
4346 					   sizeof(kvm_sigmask)))
4347 				goto out;
4348 			r = -EINVAL;
4349 			if (kvm_sigmask.len != sizeof(compat_sigset_t))
4350 				goto out;
4351 			r = -EFAULT;
4352 			if (get_compat_sigset(&sigset,
4353 					      (compat_sigset_t __user *)sigmask_arg->sigset))
4354 				goto out;
4355 			r = kvm_vcpu_ioctl_set_sigmask(vcpu, &sigset);
4356 		} else
4357 			r = kvm_vcpu_ioctl_set_sigmask(vcpu, NULL);
4358 		break;
4359 	}
4360 	default:
4361 		r = kvm_vcpu_ioctl(filp, ioctl, arg);
4362 	}
4363 
4364 out:
4365 	return r;
4366 }
4367 #endif
4368 
kvm_device_mmap(struct file * filp,struct vm_area_struct * vma)4369 static int kvm_device_mmap(struct file *filp, struct vm_area_struct *vma)
4370 {
4371 	struct kvm_device *dev = filp->private_data;
4372 
4373 	if (dev->ops->mmap)
4374 		return dev->ops->mmap(dev, vma);
4375 
4376 	return -ENODEV;
4377 }
4378 
kvm_device_ioctl_attr(struct kvm_device * dev,int (* accessor)(struct kvm_device * dev,struct kvm_device_attr * attr),unsigned long arg)4379 static int kvm_device_ioctl_attr(struct kvm_device *dev,
4380 				 int (*accessor)(struct kvm_device *dev,
4381 						 struct kvm_device_attr *attr),
4382 				 unsigned long arg)
4383 {
4384 	struct kvm_device_attr attr;
4385 
4386 	if (!accessor)
4387 		return -EPERM;
4388 
4389 	if (copy_from_user(&attr, (void __user *)arg, sizeof(attr)))
4390 		return -EFAULT;
4391 
4392 	return accessor(dev, &attr);
4393 }
4394 
kvm_device_ioctl(struct file * filp,unsigned int ioctl,unsigned long arg)4395 static long kvm_device_ioctl(struct file *filp, unsigned int ioctl,
4396 			     unsigned long arg)
4397 {
4398 	struct kvm_device *dev = filp->private_data;
4399 
4400 	if (dev->kvm->mm != current->mm || dev->kvm->vm_dead)
4401 		return -EIO;
4402 
4403 	switch (ioctl) {
4404 	case KVM_SET_DEVICE_ATTR:
4405 		return kvm_device_ioctl_attr(dev, dev->ops->set_attr, arg);
4406 	case KVM_GET_DEVICE_ATTR:
4407 		return kvm_device_ioctl_attr(dev, dev->ops->get_attr, arg);
4408 	case KVM_HAS_DEVICE_ATTR:
4409 		return kvm_device_ioctl_attr(dev, dev->ops->has_attr, arg);
4410 	default:
4411 		if (dev->ops->ioctl)
4412 			return dev->ops->ioctl(dev, ioctl, arg);
4413 
4414 		return -ENOTTY;
4415 	}
4416 }
4417 
kvm_device_release(struct inode * inode,struct file * filp)4418 static int kvm_device_release(struct inode *inode, struct file *filp)
4419 {
4420 	struct kvm_device *dev = filp->private_data;
4421 	struct kvm *kvm = dev->kvm;
4422 
4423 	if (dev->ops->release) {
4424 		mutex_lock(&kvm->lock);
4425 		list_del(&dev->vm_node);
4426 		dev->ops->release(dev);
4427 		mutex_unlock(&kvm->lock);
4428 	}
4429 
4430 	kvm_put_kvm(kvm);
4431 	return 0;
4432 }
4433 
4434 static const struct file_operations kvm_device_fops = {
4435 	.unlocked_ioctl = kvm_device_ioctl,
4436 	.release = kvm_device_release,
4437 	KVM_COMPAT(kvm_device_ioctl),
4438 	.mmap = kvm_device_mmap,
4439 };
4440 
kvm_device_from_filp(struct file * filp)4441 struct kvm_device *kvm_device_from_filp(struct file *filp)
4442 {
4443 	if (filp->f_op != &kvm_device_fops)
4444 		return NULL;
4445 
4446 	return filp->private_data;
4447 }
4448 
4449 static const struct kvm_device_ops *kvm_device_ops_table[KVM_DEV_TYPE_MAX] = {
4450 #ifdef CONFIG_KVM_MPIC
4451 	[KVM_DEV_TYPE_FSL_MPIC_20]	= &kvm_mpic_ops,
4452 	[KVM_DEV_TYPE_FSL_MPIC_42]	= &kvm_mpic_ops,
4453 #endif
4454 };
4455 
kvm_register_device_ops(const struct kvm_device_ops * ops,u32 type)4456 int kvm_register_device_ops(const struct kvm_device_ops *ops, u32 type)
4457 {
4458 	if (type >= ARRAY_SIZE(kvm_device_ops_table))
4459 		return -ENOSPC;
4460 
4461 	if (kvm_device_ops_table[type] != NULL)
4462 		return -EEXIST;
4463 
4464 	kvm_device_ops_table[type] = ops;
4465 	return 0;
4466 }
4467 
kvm_unregister_device_ops(u32 type)4468 void kvm_unregister_device_ops(u32 type)
4469 {
4470 	if (kvm_device_ops_table[type] != NULL)
4471 		kvm_device_ops_table[type] = NULL;
4472 }
4473 
kvm_ioctl_create_device(struct kvm * kvm,struct kvm_create_device * cd)4474 static int kvm_ioctl_create_device(struct kvm *kvm,
4475 				   struct kvm_create_device *cd)
4476 {
4477 	const struct kvm_device_ops *ops;
4478 	struct kvm_device *dev;
4479 	bool test = cd->flags & KVM_CREATE_DEVICE_TEST;
4480 	int type;
4481 	int ret;
4482 
4483 	if (cd->type >= ARRAY_SIZE(kvm_device_ops_table))
4484 		return -ENODEV;
4485 
4486 	type = array_index_nospec(cd->type, ARRAY_SIZE(kvm_device_ops_table));
4487 	ops = kvm_device_ops_table[type];
4488 	if (ops == NULL)
4489 		return -ENODEV;
4490 
4491 	if (test)
4492 		return 0;
4493 
4494 	dev = kzalloc(sizeof(*dev), GFP_KERNEL_ACCOUNT);
4495 	if (!dev)
4496 		return -ENOMEM;
4497 
4498 	dev->ops = ops;
4499 	dev->kvm = kvm;
4500 
4501 	mutex_lock(&kvm->lock);
4502 	ret = ops->create(dev, type);
4503 	if (ret < 0) {
4504 		mutex_unlock(&kvm->lock);
4505 		kfree(dev);
4506 		return ret;
4507 	}
4508 	list_add(&dev->vm_node, &kvm->devices);
4509 	mutex_unlock(&kvm->lock);
4510 
4511 	if (ops->init)
4512 		ops->init(dev);
4513 
4514 	kvm_get_kvm(kvm);
4515 	ret = anon_inode_getfd(ops->name, &kvm_device_fops, dev, O_RDWR | O_CLOEXEC);
4516 	if (ret < 0) {
4517 		kvm_put_kvm_no_destroy(kvm);
4518 		mutex_lock(&kvm->lock);
4519 		list_del(&dev->vm_node);
4520 		if (ops->release)
4521 			ops->release(dev);
4522 		mutex_unlock(&kvm->lock);
4523 		if (ops->destroy)
4524 			ops->destroy(dev);
4525 		return ret;
4526 	}
4527 
4528 	cd->fd = ret;
4529 	return 0;
4530 }
4531 
kvm_vm_ioctl_check_extension_generic(struct kvm * kvm,long arg)4532 static int kvm_vm_ioctl_check_extension_generic(struct kvm *kvm, long arg)
4533 {
4534 	switch (arg) {
4535 	case KVM_CAP_USER_MEMORY:
4536 	case KVM_CAP_DESTROY_MEMORY_REGION_WORKS:
4537 	case KVM_CAP_JOIN_MEMORY_REGIONS_WORKS:
4538 	case KVM_CAP_INTERNAL_ERROR_DATA:
4539 #ifdef CONFIG_HAVE_KVM_MSI
4540 	case KVM_CAP_SIGNAL_MSI:
4541 #endif
4542 #ifdef CONFIG_HAVE_KVM_IRQFD
4543 	case KVM_CAP_IRQFD:
4544 #endif
4545 	case KVM_CAP_IOEVENTFD_ANY_LENGTH:
4546 	case KVM_CAP_CHECK_EXTENSION_VM:
4547 	case KVM_CAP_ENABLE_CAP_VM:
4548 	case KVM_CAP_HALT_POLL:
4549 		return 1;
4550 #ifdef CONFIG_KVM_MMIO
4551 	case KVM_CAP_COALESCED_MMIO:
4552 		return KVM_COALESCED_MMIO_PAGE_OFFSET;
4553 	case KVM_CAP_COALESCED_PIO:
4554 		return 1;
4555 #endif
4556 #ifdef CONFIG_KVM_GENERIC_DIRTYLOG_READ_PROTECT
4557 	case KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2:
4558 		return KVM_DIRTY_LOG_MANUAL_CAPS;
4559 #endif
4560 #ifdef CONFIG_HAVE_KVM_IRQ_ROUTING
4561 	case KVM_CAP_IRQ_ROUTING:
4562 		return KVM_MAX_IRQ_ROUTES;
4563 #endif
4564 #if KVM_ADDRESS_SPACE_NUM > 1
4565 	case KVM_CAP_MULTI_ADDRESS_SPACE:
4566 		return KVM_ADDRESS_SPACE_NUM;
4567 #endif
4568 	case KVM_CAP_NR_MEMSLOTS:
4569 		return KVM_USER_MEM_SLOTS;
4570 	case KVM_CAP_DIRTY_LOG_RING:
4571 #ifdef CONFIG_HAVE_KVM_DIRTY_RING_TSO
4572 		return KVM_DIRTY_RING_MAX_ENTRIES * sizeof(struct kvm_dirty_gfn);
4573 #else
4574 		return 0;
4575 #endif
4576 	case KVM_CAP_DIRTY_LOG_RING_ACQ_REL:
4577 #ifdef CONFIG_HAVE_KVM_DIRTY_RING_ACQ_REL
4578 		return KVM_DIRTY_RING_MAX_ENTRIES * sizeof(struct kvm_dirty_gfn);
4579 #else
4580 		return 0;
4581 #endif
4582 #ifdef CONFIG_NEED_KVM_DIRTY_RING_WITH_BITMAP
4583 	case KVM_CAP_DIRTY_LOG_RING_WITH_BITMAP:
4584 #endif
4585 	case KVM_CAP_BINARY_STATS_FD:
4586 	case KVM_CAP_SYSTEM_EVENT_DATA:
4587 		return 1;
4588 	default:
4589 		break;
4590 	}
4591 	return kvm_vm_ioctl_check_extension(kvm, arg);
4592 }
4593 
kvm_vm_ioctl_enable_dirty_log_ring(struct kvm * kvm,u32 size)4594 static int kvm_vm_ioctl_enable_dirty_log_ring(struct kvm *kvm, u32 size)
4595 {
4596 	int r;
4597 
4598 	if (!KVM_DIRTY_LOG_PAGE_OFFSET)
4599 		return -EINVAL;
4600 
4601 	/* the size should be power of 2 */
4602 	if (!size || (size & (size - 1)))
4603 		return -EINVAL;
4604 
4605 	/* Should be bigger to keep the reserved entries, or a page */
4606 	if (size < kvm_dirty_ring_get_rsvd_entries() *
4607 	    sizeof(struct kvm_dirty_gfn) || size < PAGE_SIZE)
4608 		return -EINVAL;
4609 
4610 	if (size > KVM_DIRTY_RING_MAX_ENTRIES *
4611 	    sizeof(struct kvm_dirty_gfn))
4612 		return -E2BIG;
4613 
4614 	/* We only allow it to set once */
4615 	if (kvm->dirty_ring_size)
4616 		return -EINVAL;
4617 
4618 	mutex_lock(&kvm->lock);
4619 
4620 	if (kvm->created_vcpus) {
4621 		/* We don't allow to change this value after vcpu created */
4622 		r = -EINVAL;
4623 	} else {
4624 		kvm->dirty_ring_size = size;
4625 		r = 0;
4626 	}
4627 
4628 	mutex_unlock(&kvm->lock);
4629 	return r;
4630 }
4631 
kvm_vm_ioctl_reset_dirty_pages(struct kvm * kvm)4632 static int kvm_vm_ioctl_reset_dirty_pages(struct kvm *kvm)
4633 {
4634 	unsigned long i;
4635 	struct kvm_vcpu *vcpu;
4636 	int cleared = 0;
4637 
4638 	if (!kvm->dirty_ring_size)
4639 		return -EINVAL;
4640 
4641 	mutex_lock(&kvm->slots_lock);
4642 
4643 	kvm_for_each_vcpu(i, vcpu, kvm)
4644 		cleared += kvm_dirty_ring_reset(vcpu->kvm, &vcpu->dirty_ring);
4645 
4646 	mutex_unlock(&kvm->slots_lock);
4647 
4648 	if (cleared)
4649 		kvm_flush_remote_tlbs(kvm);
4650 
4651 	return cleared;
4652 }
4653 
kvm_vm_ioctl_enable_cap(struct kvm * kvm,struct kvm_enable_cap * cap)4654 int __attribute__((weak)) kvm_vm_ioctl_enable_cap(struct kvm *kvm,
4655 						  struct kvm_enable_cap *cap)
4656 {
4657 	return -EINVAL;
4658 }
4659 
kvm_are_all_memslots_empty(struct kvm * kvm)4660 bool kvm_are_all_memslots_empty(struct kvm *kvm)
4661 {
4662 	int i;
4663 
4664 	lockdep_assert_held(&kvm->slots_lock);
4665 
4666 	for (i = 0; i < KVM_ADDRESS_SPACE_NUM; i++) {
4667 		if (!kvm_memslots_empty(__kvm_memslots(kvm, i)))
4668 			return false;
4669 	}
4670 
4671 	return true;
4672 }
4673 EXPORT_SYMBOL_GPL(kvm_are_all_memslots_empty);
4674 
kvm_vm_ioctl_enable_cap_generic(struct kvm * kvm,struct kvm_enable_cap * cap)4675 static int kvm_vm_ioctl_enable_cap_generic(struct kvm *kvm,
4676 					   struct kvm_enable_cap *cap)
4677 {
4678 	switch (cap->cap) {
4679 #ifdef CONFIG_KVM_GENERIC_DIRTYLOG_READ_PROTECT
4680 	case KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2: {
4681 		u64 allowed_options = KVM_DIRTY_LOG_MANUAL_PROTECT_ENABLE;
4682 
4683 		if (cap->args[0] & KVM_DIRTY_LOG_MANUAL_PROTECT_ENABLE)
4684 			allowed_options = KVM_DIRTY_LOG_MANUAL_CAPS;
4685 
4686 		if (cap->flags || (cap->args[0] & ~allowed_options))
4687 			return -EINVAL;
4688 		kvm->manual_dirty_log_protect = cap->args[0];
4689 		return 0;
4690 	}
4691 #endif
4692 	case KVM_CAP_HALT_POLL: {
4693 		if (cap->flags || cap->args[0] != (unsigned int)cap->args[0])
4694 			return -EINVAL;
4695 
4696 		kvm->max_halt_poll_ns = cap->args[0];
4697 
4698 		/*
4699 		 * Ensure kvm->override_halt_poll_ns does not become visible
4700 		 * before kvm->max_halt_poll_ns.
4701 		 *
4702 		 * Pairs with the smp_rmb() in kvm_vcpu_max_halt_poll_ns().
4703 		 */
4704 		smp_wmb();
4705 		kvm->override_halt_poll_ns = true;
4706 
4707 		return 0;
4708 	}
4709 	case KVM_CAP_DIRTY_LOG_RING:
4710 	case KVM_CAP_DIRTY_LOG_RING_ACQ_REL:
4711 		if (!kvm_vm_ioctl_check_extension_generic(kvm, cap->cap))
4712 			return -EINVAL;
4713 
4714 		return kvm_vm_ioctl_enable_dirty_log_ring(kvm, cap->args[0]);
4715 	case KVM_CAP_DIRTY_LOG_RING_WITH_BITMAP: {
4716 		int r = -EINVAL;
4717 
4718 		if (!IS_ENABLED(CONFIG_NEED_KVM_DIRTY_RING_WITH_BITMAP) ||
4719 		    !kvm->dirty_ring_size || cap->flags)
4720 			return r;
4721 
4722 		mutex_lock(&kvm->slots_lock);
4723 
4724 		/*
4725 		 * For simplicity, allow enabling ring+bitmap if and only if
4726 		 * there are no memslots, e.g. to ensure all memslots allocate
4727 		 * a bitmap after the capability is enabled.
4728 		 */
4729 		if (kvm_are_all_memslots_empty(kvm)) {
4730 			kvm->dirty_ring_with_bitmap = true;
4731 			r = 0;
4732 		}
4733 
4734 		mutex_unlock(&kvm->slots_lock);
4735 
4736 		return r;
4737 	}
4738 	default:
4739 		return kvm_vm_ioctl_enable_cap(kvm, cap);
4740 	}
4741 }
4742 
kvm_vm_stats_read(struct file * file,char __user * user_buffer,size_t size,loff_t * offset)4743 static ssize_t kvm_vm_stats_read(struct file *file, char __user *user_buffer,
4744 			      size_t size, loff_t *offset)
4745 {
4746 	struct kvm *kvm = file->private_data;
4747 
4748 	return kvm_stats_read(kvm->stats_id, &kvm_vm_stats_header,
4749 				&kvm_vm_stats_desc[0], &kvm->stat,
4750 				sizeof(kvm->stat), user_buffer, size, offset);
4751 }
4752 
kvm_vm_stats_release(struct inode * inode,struct file * file)4753 static int kvm_vm_stats_release(struct inode *inode, struct file *file)
4754 {
4755 	struct kvm *kvm = file->private_data;
4756 
4757 	kvm_put_kvm(kvm);
4758 	return 0;
4759 }
4760 
4761 static const struct file_operations kvm_vm_stats_fops = {
4762 	.read = kvm_vm_stats_read,
4763 	.release = kvm_vm_stats_release,
4764 	.llseek = noop_llseek,
4765 };
4766 
kvm_vm_ioctl_get_stats_fd(struct kvm * kvm)4767 static int kvm_vm_ioctl_get_stats_fd(struct kvm *kvm)
4768 {
4769 	int fd;
4770 	struct file *file;
4771 
4772 	fd = get_unused_fd_flags(O_CLOEXEC);
4773 	if (fd < 0)
4774 		return fd;
4775 
4776 	file = anon_inode_getfile("kvm-vm-stats",
4777 			&kvm_vm_stats_fops, kvm, O_RDONLY);
4778 	if (IS_ERR(file)) {
4779 		put_unused_fd(fd);
4780 		return PTR_ERR(file);
4781 	}
4782 
4783 	kvm_get_kvm(kvm);
4784 
4785 	file->f_mode |= FMODE_PREAD;
4786 	fd_install(fd, file);
4787 
4788 	return fd;
4789 }
4790 
kvm_vm_ioctl(struct file * filp,unsigned int ioctl,unsigned long arg)4791 static long kvm_vm_ioctl(struct file *filp,
4792 			   unsigned int ioctl, unsigned long arg)
4793 {
4794 	struct kvm *kvm = filp->private_data;
4795 	void __user *argp = (void __user *)arg;
4796 	int r;
4797 
4798 	if (kvm->mm != current->mm || kvm->vm_dead)
4799 		return -EIO;
4800 	switch (ioctl) {
4801 	case KVM_CREATE_VCPU:
4802 		r = kvm_vm_ioctl_create_vcpu(kvm, arg);
4803 		break;
4804 	case KVM_ENABLE_CAP: {
4805 		struct kvm_enable_cap cap;
4806 
4807 		r = -EFAULT;
4808 		if (copy_from_user(&cap, argp, sizeof(cap)))
4809 			goto out;
4810 		r = kvm_vm_ioctl_enable_cap_generic(kvm, &cap);
4811 		break;
4812 	}
4813 	case KVM_SET_USER_MEMORY_REGION: {
4814 		struct kvm_userspace_memory_region kvm_userspace_mem;
4815 
4816 		r = -EFAULT;
4817 		if (copy_from_user(&kvm_userspace_mem, argp,
4818 						sizeof(kvm_userspace_mem)))
4819 			goto out;
4820 
4821 		r = kvm_vm_ioctl_set_memory_region(kvm, &kvm_userspace_mem);
4822 		break;
4823 	}
4824 	case KVM_GET_DIRTY_LOG: {
4825 		struct kvm_dirty_log log;
4826 
4827 		r = -EFAULT;
4828 		if (copy_from_user(&log, argp, sizeof(log)))
4829 			goto out;
4830 		r = kvm_vm_ioctl_get_dirty_log(kvm, &log);
4831 		break;
4832 	}
4833 #ifdef CONFIG_KVM_GENERIC_DIRTYLOG_READ_PROTECT
4834 	case KVM_CLEAR_DIRTY_LOG: {
4835 		struct kvm_clear_dirty_log log;
4836 
4837 		r = -EFAULT;
4838 		if (copy_from_user(&log, argp, sizeof(log)))
4839 			goto out;
4840 		r = kvm_vm_ioctl_clear_dirty_log(kvm, &log);
4841 		break;
4842 	}
4843 #endif
4844 #ifdef CONFIG_KVM_MMIO
4845 	case KVM_REGISTER_COALESCED_MMIO: {
4846 		struct kvm_coalesced_mmio_zone zone;
4847 
4848 		r = -EFAULT;
4849 		if (copy_from_user(&zone, argp, sizeof(zone)))
4850 			goto out;
4851 		r = kvm_vm_ioctl_register_coalesced_mmio(kvm, &zone);
4852 		break;
4853 	}
4854 	case KVM_UNREGISTER_COALESCED_MMIO: {
4855 		struct kvm_coalesced_mmio_zone zone;
4856 
4857 		r = -EFAULT;
4858 		if (copy_from_user(&zone, argp, sizeof(zone)))
4859 			goto out;
4860 		r = kvm_vm_ioctl_unregister_coalesced_mmio(kvm, &zone);
4861 		break;
4862 	}
4863 #endif
4864 	case KVM_IRQFD: {
4865 		struct kvm_irqfd data;
4866 
4867 		r = -EFAULT;
4868 		if (copy_from_user(&data, argp, sizeof(data)))
4869 			goto out;
4870 		r = kvm_irqfd(kvm, &data);
4871 		break;
4872 	}
4873 	case KVM_IOEVENTFD: {
4874 		struct kvm_ioeventfd data;
4875 
4876 		r = -EFAULT;
4877 		if (copy_from_user(&data, argp, sizeof(data)))
4878 			goto out;
4879 		r = kvm_ioeventfd(kvm, &data);
4880 		break;
4881 	}
4882 #ifdef CONFIG_HAVE_KVM_MSI
4883 	case KVM_SIGNAL_MSI: {
4884 		struct kvm_msi msi;
4885 
4886 		r = -EFAULT;
4887 		if (copy_from_user(&msi, argp, sizeof(msi)))
4888 			goto out;
4889 		r = kvm_send_userspace_msi(kvm, &msi);
4890 		break;
4891 	}
4892 #endif
4893 #ifdef __KVM_HAVE_IRQ_LINE
4894 	case KVM_IRQ_LINE_STATUS:
4895 	case KVM_IRQ_LINE: {
4896 		struct kvm_irq_level irq_event;
4897 
4898 		r = -EFAULT;
4899 		if (copy_from_user(&irq_event, argp, sizeof(irq_event)))
4900 			goto out;
4901 
4902 		r = kvm_vm_ioctl_irq_line(kvm, &irq_event,
4903 					ioctl == KVM_IRQ_LINE_STATUS);
4904 		if (r)
4905 			goto out;
4906 
4907 		r = -EFAULT;
4908 		if (ioctl == KVM_IRQ_LINE_STATUS) {
4909 			if (copy_to_user(argp, &irq_event, sizeof(irq_event)))
4910 				goto out;
4911 		}
4912 
4913 		r = 0;
4914 		break;
4915 	}
4916 #endif
4917 #ifdef CONFIG_HAVE_KVM_IRQ_ROUTING
4918 	case KVM_SET_GSI_ROUTING: {
4919 		struct kvm_irq_routing routing;
4920 		struct kvm_irq_routing __user *urouting;
4921 		struct kvm_irq_routing_entry *entries = NULL;
4922 
4923 		r = -EFAULT;
4924 		if (copy_from_user(&routing, argp, sizeof(routing)))
4925 			goto out;
4926 		r = -EINVAL;
4927 		if (!kvm_arch_can_set_irq_routing(kvm))
4928 			goto out;
4929 		if (routing.nr > KVM_MAX_IRQ_ROUTES)
4930 			goto out;
4931 		if (routing.flags)
4932 			goto out;
4933 		if (routing.nr) {
4934 			urouting = argp;
4935 			entries = vmemdup_user(urouting->entries,
4936 					       array_size(sizeof(*entries),
4937 							  routing.nr));
4938 			if (IS_ERR(entries)) {
4939 				r = PTR_ERR(entries);
4940 				goto out;
4941 			}
4942 		}
4943 		r = kvm_set_irq_routing(kvm, entries, routing.nr,
4944 					routing.flags);
4945 		kvfree(entries);
4946 		break;
4947 	}
4948 #endif /* CONFIG_HAVE_KVM_IRQ_ROUTING */
4949 	case KVM_CREATE_DEVICE: {
4950 		struct kvm_create_device cd;
4951 
4952 		r = -EFAULT;
4953 		if (copy_from_user(&cd, argp, sizeof(cd)))
4954 			goto out;
4955 
4956 		r = kvm_ioctl_create_device(kvm, &cd);
4957 		if (r)
4958 			goto out;
4959 
4960 		r = -EFAULT;
4961 		if (copy_to_user(argp, &cd, sizeof(cd)))
4962 			goto out;
4963 
4964 		r = 0;
4965 		break;
4966 	}
4967 	case KVM_CHECK_EXTENSION:
4968 		r = kvm_vm_ioctl_check_extension_generic(kvm, arg);
4969 		break;
4970 	case KVM_RESET_DIRTY_RINGS:
4971 		r = kvm_vm_ioctl_reset_dirty_pages(kvm);
4972 		break;
4973 	case KVM_GET_STATS_FD:
4974 		r = kvm_vm_ioctl_get_stats_fd(kvm);
4975 		break;
4976 	default:
4977 		r = kvm_arch_vm_ioctl(filp, ioctl, arg);
4978 	}
4979 out:
4980 	return r;
4981 }
4982 
4983 #ifdef CONFIG_KVM_COMPAT
4984 struct compat_kvm_dirty_log {
4985 	__u32 slot;
4986 	__u32 padding1;
4987 	union {
4988 		compat_uptr_t dirty_bitmap; /* one bit per page */
4989 		__u64 padding2;
4990 	};
4991 };
4992 
4993 struct compat_kvm_clear_dirty_log {
4994 	__u32 slot;
4995 	__u32 num_pages;
4996 	__u64 first_page;
4997 	union {
4998 		compat_uptr_t dirty_bitmap; /* one bit per page */
4999 		__u64 padding2;
5000 	};
5001 };
5002 
kvm_arch_vm_compat_ioctl(struct file * filp,unsigned int ioctl,unsigned long arg)5003 long __weak kvm_arch_vm_compat_ioctl(struct file *filp, unsigned int ioctl,
5004 				     unsigned long arg)
5005 {
5006 	return -ENOTTY;
5007 }
5008 
kvm_vm_compat_ioctl(struct file * filp,unsigned int ioctl,unsigned long arg)5009 static long kvm_vm_compat_ioctl(struct file *filp,
5010 			   unsigned int ioctl, unsigned long arg)
5011 {
5012 	struct kvm *kvm = filp->private_data;
5013 	int r;
5014 
5015 	if (kvm->mm != current->mm || kvm->vm_dead)
5016 		return -EIO;
5017 
5018 	r = kvm_arch_vm_compat_ioctl(filp, ioctl, arg);
5019 	if (r != -ENOTTY)
5020 		return r;
5021 
5022 	switch (ioctl) {
5023 #ifdef CONFIG_KVM_GENERIC_DIRTYLOG_READ_PROTECT
5024 	case KVM_CLEAR_DIRTY_LOG: {
5025 		struct compat_kvm_clear_dirty_log compat_log;
5026 		struct kvm_clear_dirty_log log;
5027 
5028 		if (copy_from_user(&compat_log, (void __user *)arg,
5029 				   sizeof(compat_log)))
5030 			return -EFAULT;
5031 		log.slot	 = compat_log.slot;
5032 		log.num_pages	 = compat_log.num_pages;
5033 		log.first_page	 = compat_log.first_page;
5034 		log.padding2	 = compat_log.padding2;
5035 		log.dirty_bitmap = compat_ptr(compat_log.dirty_bitmap);
5036 
5037 		r = kvm_vm_ioctl_clear_dirty_log(kvm, &log);
5038 		break;
5039 	}
5040 #endif
5041 	case KVM_GET_DIRTY_LOG: {
5042 		struct compat_kvm_dirty_log compat_log;
5043 		struct kvm_dirty_log log;
5044 
5045 		if (copy_from_user(&compat_log, (void __user *)arg,
5046 				   sizeof(compat_log)))
5047 			return -EFAULT;
5048 		log.slot	 = compat_log.slot;
5049 		log.padding1	 = compat_log.padding1;
5050 		log.padding2	 = compat_log.padding2;
5051 		log.dirty_bitmap = compat_ptr(compat_log.dirty_bitmap);
5052 
5053 		r = kvm_vm_ioctl_get_dirty_log(kvm, &log);
5054 		break;
5055 	}
5056 	default:
5057 		r = kvm_vm_ioctl(filp, ioctl, arg);
5058 	}
5059 	return r;
5060 }
5061 #endif
5062 
5063 static const struct file_operations kvm_vm_fops = {
5064 	.release        = kvm_vm_release,
5065 	.unlocked_ioctl = kvm_vm_ioctl,
5066 	.llseek		= noop_llseek,
5067 	KVM_COMPAT(kvm_vm_compat_ioctl),
5068 };
5069 
file_is_kvm(struct file * file)5070 bool file_is_kvm(struct file *file)
5071 {
5072 	return file && file->f_op == &kvm_vm_fops;
5073 }
5074 EXPORT_SYMBOL_GPL(file_is_kvm);
5075 
kvm_dev_ioctl_create_vm(unsigned long type)5076 static int kvm_dev_ioctl_create_vm(unsigned long type)
5077 {
5078 	char fdname[ITOA_MAX_LEN + 1];
5079 	int r, fd;
5080 	struct kvm *kvm;
5081 	struct file *file;
5082 
5083 	fd = get_unused_fd_flags(O_CLOEXEC);
5084 	if (fd < 0)
5085 		return fd;
5086 
5087 	snprintf(fdname, sizeof(fdname), "%d", fd);
5088 
5089 	kvm = kvm_create_vm(type, fdname);
5090 	if (IS_ERR(kvm)) {
5091 		r = PTR_ERR(kvm);
5092 		goto put_fd;
5093 	}
5094 
5095 	file = anon_inode_getfile("kvm-vm", &kvm_vm_fops, kvm, O_RDWR);
5096 	if (IS_ERR(file)) {
5097 		r = PTR_ERR(file);
5098 		goto put_kvm;
5099 	}
5100 
5101 	/*
5102 	 * Don't call kvm_put_kvm anymore at this point; file->f_op is
5103 	 * already set, with ->release() being kvm_vm_release().  In error
5104 	 * cases it will be called by the final fput(file) and will take
5105 	 * care of doing kvm_put_kvm(kvm).
5106 	 */
5107 	kvm_uevent_notify_change(KVM_EVENT_CREATE_VM, kvm);
5108 
5109 	fd_install(fd, file);
5110 	return fd;
5111 
5112 put_kvm:
5113 	kvm_put_kvm(kvm);
5114 put_fd:
5115 	put_unused_fd(fd);
5116 	return r;
5117 }
5118 
kvm_dev_ioctl(struct file * filp,unsigned int ioctl,unsigned long arg)5119 static long kvm_dev_ioctl(struct file *filp,
5120 			  unsigned int ioctl, unsigned long arg)
5121 {
5122 	int r = -EINVAL;
5123 
5124 	switch (ioctl) {
5125 	case KVM_GET_API_VERSION:
5126 		if (arg)
5127 			goto out;
5128 		r = KVM_API_VERSION;
5129 		break;
5130 	case KVM_CREATE_VM:
5131 		r = kvm_dev_ioctl_create_vm(arg);
5132 		break;
5133 	case KVM_CHECK_EXTENSION:
5134 		r = kvm_vm_ioctl_check_extension_generic(NULL, arg);
5135 		break;
5136 	case KVM_GET_VCPU_MMAP_SIZE:
5137 		if (arg)
5138 			goto out;
5139 		r = PAGE_SIZE;     /* struct kvm_run */
5140 #ifdef CONFIG_X86
5141 		r += PAGE_SIZE;    /* pio data page */
5142 #endif
5143 #ifdef CONFIG_KVM_MMIO
5144 		r += PAGE_SIZE;    /* coalesced mmio ring page */
5145 #endif
5146 		break;
5147 	case KVM_TRACE_ENABLE:
5148 	case KVM_TRACE_PAUSE:
5149 	case KVM_TRACE_DISABLE:
5150 		r = -EOPNOTSUPP;
5151 		break;
5152 	default:
5153 		return kvm_arch_dev_ioctl(filp, ioctl, arg);
5154 	}
5155 out:
5156 	return r;
5157 }
5158 
5159 static struct file_operations kvm_chardev_ops = {
5160 	.unlocked_ioctl = kvm_dev_ioctl,
5161 	.llseek		= noop_llseek,
5162 	KVM_COMPAT(kvm_dev_ioctl),
5163 };
5164 
5165 static struct miscdevice kvm_dev = {
5166 	KVM_MINOR,
5167 	"kvm",
5168 	&kvm_chardev_ops,
5169 };
5170 
5171 #ifdef CONFIG_KVM_GENERIC_HARDWARE_ENABLING
5172 __visible bool kvm_rebooting;
5173 EXPORT_SYMBOL_GPL(kvm_rebooting);
5174 
5175 static DEFINE_PER_CPU(bool, hardware_enabled);
5176 static int kvm_usage_count;
5177 
__hardware_enable_nolock(void)5178 static int __hardware_enable_nolock(void)
5179 {
5180 	if (__this_cpu_read(hardware_enabled))
5181 		return 0;
5182 
5183 	if (kvm_arch_hardware_enable()) {
5184 		pr_info("kvm: enabling virtualization on CPU%d failed\n",
5185 			raw_smp_processor_id());
5186 		return -EIO;
5187 	}
5188 
5189 	__this_cpu_write(hardware_enabled, true);
5190 	return 0;
5191 }
5192 
hardware_enable_nolock(void * failed)5193 static void hardware_enable_nolock(void *failed)
5194 {
5195 	if (__hardware_enable_nolock())
5196 		atomic_inc(failed);
5197 }
5198 
kvm_online_cpu(unsigned int cpu)5199 static int kvm_online_cpu(unsigned int cpu)
5200 {
5201 	int ret = 0;
5202 
5203 	/*
5204 	 * Abort the CPU online process if hardware virtualization cannot
5205 	 * be enabled. Otherwise running VMs would encounter unrecoverable
5206 	 * errors when scheduled to this CPU.
5207 	 */
5208 	mutex_lock(&kvm_lock);
5209 	if (kvm_usage_count)
5210 		ret = __hardware_enable_nolock();
5211 	mutex_unlock(&kvm_lock);
5212 	return ret;
5213 }
5214 
hardware_disable_nolock(void * junk)5215 static void hardware_disable_nolock(void *junk)
5216 {
5217 	/*
5218 	 * Note, hardware_disable_all_nolock() tells all online CPUs to disable
5219 	 * hardware, not just CPUs that successfully enabled hardware!
5220 	 */
5221 	if (!__this_cpu_read(hardware_enabled))
5222 		return;
5223 
5224 	kvm_arch_hardware_disable();
5225 
5226 	__this_cpu_write(hardware_enabled, false);
5227 }
5228 
kvm_offline_cpu(unsigned int cpu)5229 static int kvm_offline_cpu(unsigned int cpu)
5230 {
5231 	mutex_lock(&kvm_lock);
5232 	if (kvm_usage_count)
5233 		hardware_disable_nolock(NULL);
5234 	mutex_unlock(&kvm_lock);
5235 	return 0;
5236 }
5237 
hardware_disable_all_nolock(void)5238 static void hardware_disable_all_nolock(void)
5239 {
5240 	BUG_ON(!kvm_usage_count);
5241 
5242 	kvm_usage_count--;
5243 	if (!kvm_usage_count)
5244 		on_each_cpu(hardware_disable_nolock, NULL, 1);
5245 }
5246 
hardware_disable_all(void)5247 static void hardware_disable_all(void)
5248 {
5249 	cpus_read_lock();
5250 	mutex_lock(&kvm_lock);
5251 	hardware_disable_all_nolock();
5252 	mutex_unlock(&kvm_lock);
5253 	cpus_read_unlock();
5254 }
5255 
hardware_enable_all(void)5256 static int hardware_enable_all(void)
5257 {
5258 	atomic_t failed = ATOMIC_INIT(0);
5259 	int r;
5260 
5261 	/*
5262 	 * Do not enable hardware virtualization if the system is going down.
5263 	 * If userspace initiated a forced reboot, e.g. reboot -f, then it's
5264 	 * possible for an in-flight KVM_CREATE_VM to trigger hardware enabling
5265 	 * after kvm_reboot() is called.  Note, this relies on system_state
5266 	 * being set _before_ kvm_reboot(), which is why KVM uses a syscore ops
5267 	 * hook instead of registering a dedicated reboot notifier (the latter
5268 	 * runs before system_state is updated).
5269 	 */
5270 	if (system_state == SYSTEM_HALT || system_state == SYSTEM_POWER_OFF ||
5271 	    system_state == SYSTEM_RESTART)
5272 		return -EBUSY;
5273 
5274 	/*
5275 	 * When onlining a CPU, cpu_online_mask is set before kvm_online_cpu()
5276 	 * is called, and so on_each_cpu() between them includes the CPU that
5277 	 * is being onlined.  As a result, hardware_enable_nolock() may get
5278 	 * invoked before kvm_online_cpu(), which also enables hardware if the
5279 	 * usage count is non-zero.  Disable CPU hotplug to avoid attempting to
5280 	 * enable hardware multiple times.
5281 	 */
5282 	cpus_read_lock();
5283 	mutex_lock(&kvm_lock);
5284 
5285 	r = 0;
5286 
5287 	kvm_usage_count++;
5288 	if (kvm_usage_count == 1) {
5289 		on_each_cpu(hardware_enable_nolock, &failed, 1);
5290 
5291 		if (atomic_read(&failed)) {
5292 			hardware_disable_all_nolock();
5293 			r = -EBUSY;
5294 		}
5295 	}
5296 
5297 	mutex_unlock(&kvm_lock);
5298 	cpus_read_unlock();
5299 
5300 	return r;
5301 }
5302 
kvm_shutdown(void)5303 static void kvm_shutdown(void)
5304 {
5305 	/*
5306 	 * Disable hardware virtualization and set kvm_rebooting to indicate
5307 	 * that KVM has asynchronously disabled hardware virtualization, i.e.
5308 	 * that relevant errors and exceptions aren't entirely unexpected.
5309 	 * Some flavors of hardware virtualization need to be disabled before
5310 	 * transferring control to firmware (to perform shutdown/reboot), e.g.
5311 	 * on x86, virtualization can block INIT interrupts, which are used by
5312 	 * firmware to pull APs back under firmware control.  Note, this path
5313 	 * is used for both shutdown and reboot scenarios, i.e. neither name is
5314 	 * 100% comprehensive.
5315 	 */
5316 	pr_info("kvm: exiting hardware virtualization\n");
5317 	kvm_rebooting = true;
5318 	on_each_cpu(hardware_disable_nolock, NULL, 1);
5319 }
5320 
kvm_suspend(void)5321 static int kvm_suspend(void)
5322 {
5323 	/*
5324 	 * Secondary CPUs and CPU hotplug are disabled across the suspend/resume
5325 	 * callbacks, i.e. no need to acquire kvm_lock to ensure the usage count
5326 	 * is stable.  Assert that kvm_lock is not held to ensure the system
5327 	 * isn't suspended while KVM is enabling hardware.  Hardware enabling
5328 	 * can be preempted, but the task cannot be frozen until it has dropped
5329 	 * all locks (userspace tasks are frozen via a fake signal).
5330 	 */
5331 	lockdep_assert_not_held(&kvm_lock);
5332 	lockdep_assert_irqs_disabled();
5333 
5334 	if (kvm_usage_count)
5335 		hardware_disable_nolock(NULL);
5336 	return 0;
5337 }
5338 
kvm_resume(void)5339 static void kvm_resume(void)
5340 {
5341 	lockdep_assert_not_held(&kvm_lock);
5342 	lockdep_assert_irqs_disabled();
5343 
5344 	if (kvm_usage_count)
5345 		WARN_ON_ONCE(__hardware_enable_nolock());
5346 }
5347 
5348 static struct syscore_ops kvm_syscore_ops = {
5349 	.suspend = kvm_suspend,
5350 	.resume = kvm_resume,
5351 	.shutdown = kvm_shutdown,
5352 };
5353 #else /* CONFIG_KVM_GENERIC_HARDWARE_ENABLING */
hardware_enable_all(void)5354 static int hardware_enable_all(void)
5355 {
5356 	return 0;
5357 }
5358 
hardware_disable_all(void)5359 static void hardware_disable_all(void)
5360 {
5361 
5362 }
5363 #endif /* CONFIG_KVM_GENERIC_HARDWARE_ENABLING */
5364 
kvm_iodevice_destructor(struct kvm_io_device * dev)5365 static void kvm_iodevice_destructor(struct kvm_io_device *dev)
5366 {
5367 	if (dev->ops->destructor)
5368 		dev->ops->destructor(dev);
5369 }
5370 
kvm_io_bus_destroy(struct kvm_io_bus * bus)5371 static void kvm_io_bus_destroy(struct kvm_io_bus *bus)
5372 {
5373 	int i;
5374 
5375 	for (i = 0; i < bus->dev_count; i++) {
5376 		struct kvm_io_device *pos = bus->range[i].dev;
5377 
5378 		kvm_iodevice_destructor(pos);
5379 	}
5380 	kfree(bus);
5381 }
5382 
kvm_io_bus_cmp(const struct kvm_io_range * r1,const struct kvm_io_range * r2)5383 static inline int kvm_io_bus_cmp(const struct kvm_io_range *r1,
5384 				 const struct kvm_io_range *r2)
5385 {
5386 	gpa_t addr1 = r1->addr;
5387 	gpa_t addr2 = r2->addr;
5388 
5389 	if (addr1 < addr2)
5390 		return -1;
5391 
5392 	/* If r2->len == 0, match the exact address.  If r2->len != 0,
5393 	 * accept any overlapping write.  Any order is acceptable for
5394 	 * overlapping ranges, because kvm_io_bus_get_first_dev ensures
5395 	 * we process all of them.
5396 	 */
5397 	if (r2->len) {
5398 		addr1 += r1->len;
5399 		addr2 += r2->len;
5400 	}
5401 
5402 	if (addr1 > addr2)
5403 		return 1;
5404 
5405 	return 0;
5406 }
5407 
kvm_io_bus_sort_cmp(const void * p1,const void * p2)5408 static int kvm_io_bus_sort_cmp(const void *p1, const void *p2)
5409 {
5410 	return kvm_io_bus_cmp(p1, p2);
5411 }
5412 
kvm_io_bus_get_first_dev(struct kvm_io_bus * bus,gpa_t addr,int len)5413 static int kvm_io_bus_get_first_dev(struct kvm_io_bus *bus,
5414 			     gpa_t addr, int len)
5415 {
5416 	struct kvm_io_range *range, key;
5417 	int off;
5418 
5419 	key = (struct kvm_io_range) {
5420 		.addr = addr,
5421 		.len = len,
5422 	};
5423 
5424 	range = bsearch(&key, bus->range, bus->dev_count,
5425 			sizeof(struct kvm_io_range), kvm_io_bus_sort_cmp);
5426 	if (range == NULL)
5427 		return -ENOENT;
5428 
5429 	off = range - bus->range;
5430 
5431 	while (off > 0 && kvm_io_bus_cmp(&key, &bus->range[off-1]) == 0)
5432 		off--;
5433 
5434 	return off;
5435 }
5436 
__kvm_io_bus_write(struct kvm_vcpu * vcpu,struct kvm_io_bus * bus,struct kvm_io_range * range,const void * val)5437 static int __kvm_io_bus_write(struct kvm_vcpu *vcpu, struct kvm_io_bus *bus,
5438 			      struct kvm_io_range *range, const void *val)
5439 {
5440 	int idx;
5441 
5442 	idx = kvm_io_bus_get_first_dev(bus, range->addr, range->len);
5443 	if (idx < 0)
5444 		return -EOPNOTSUPP;
5445 
5446 	while (idx < bus->dev_count &&
5447 		kvm_io_bus_cmp(range, &bus->range[idx]) == 0) {
5448 		if (!kvm_iodevice_write(vcpu, bus->range[idx].dev, range->addr,
5449 					range->len, val))
5450 			return idx;
5451 		idx++;
5452 	}
5453 
5454 	return -EOPNOTSUPP;
5455 }
5456 
5457 /* kvm_io_bus_write - called under kvm->slots_lock */
kvm_io_bus_write(struct kvm_vcpu * vcpu,enum kvm_bus bus_idx,gpa_t addr,int len,const void * val)5458 int kvm_io_bus_write(struct kvm_vcpu *vcpu, enum kvm_bus bus_idx, gpa_t addr,
5459 		     int len, const void *val)
5460 {
5461 	struct kvm_io_bus *bus;
5462 	struct kvm_io_range range;
5463 	int r;
5464 
5465 	range = (struct kvm_io_range) {
5466 		.addr = addr,
5467 		.len = len,
5468 	};
5469 
5470 	bus = srcu_dereference(vcpu->kvm->buses[bus_idx], &vcpu->kvm->srcu);
5471 	if (!bus)
5472 		return -ENOMEM;
5473 	r = __kvm_io_bus_write(vcpu, bus, &range, val);
5474 	return r < 0 ? r : 0;
5475 }
5476 EXPORT_SYMBOL_GPL(kvm_io_bus_write);
5477 
5478 /* kvm_io_bus_write_cookie - called under kvm->slots_lock */
kvm_io_bus_write_cookie(struct kvm_vcpu * vcpu,enum kvm_bus bus_idx,gpa_t addr,int len,const void * val,long cookie)5479 int kvm_io_bus_write_cookie(struct kvm_vcpu *vcpu, enum kvm_bus bus_idx,
5480 			    gpa_t addr, int len, const void *val, long cookie)
5481 {
5482 	struct kvm_io_bus *bus;
5483 	struct kvm_io_range range;
5484 
5485 	range = (struct kvm_io_range) {
5486 		.addr = addr,
5487 		.len = len,
5488 	};
5489 
5490 	bus = srcu_dereference(vcpu->kvm->buses[bus_idx], &vcpu->kvm->srcu);
5491 	if (!bus)
5492 		return -ENOMEM;
5493 
5494 	/* First try the device referenced by cookie. */
5495 	if ((cookie >= 0) && (cookie < bus->dev_count) &&
5496 	    (kvm_io_bus_cmp(&range, &bus->range[cookie]) == 0))
5497 		if (!kvm_iodevice_write(vcpu, bus->range[cookie].dev, addr, len,
5498 					val))
5499 			return cookie;
5500 
5501 	/*
5502 	 * cookie contained garbage; fall back to search and return the
5503 	 * correct cookie value.
5504 	 */
5505 	return __kvm_io_bus_write(vcpu, bus, &range, val);
5506 }
5507 
__kvm_io_bus_read(struct kvm_vcpu * vcpu,struct kvm_io_bus * bus,struct kvm_io_range * range,void * val)5508 static int __kvm_io_bus_read(struct kvm_vcpu *vcpu, struct kvm_io_bus *bus,
5509 			     struct kvm_io_range *range, void *val)
5510 {
5511 	int idx;
5512 
5513 	idx = kvm_io_bus_get_first_dev(bus, range->addr, range->len);
5514 	if (idx < 0)
5515 		return -EOPNOTSUPP;
5516 
5517 	while (idx < bus->dev_count &&
5518 		kvm_io_bus_cmp(range, &bus->range[idx]) == 0) {
5519 		if (!kvm_iodevice_read(vcpu, bus->range[idx].dev, range->addr,
5520 				       range->len, val))
5521 			return idx;
5522 		idx++;
5523 	}
5524 
5525 	return -EOPNOTSUPP;
5526 }
5527 
5528 /* kvm_io_bus_read - called under kvm->slots_lock */
kvm_io_bus_read(struct kvm_vcpu * vcpu,enum kvm_bus bus_idx,gpa_t addr,int len,void * val)5529 int kvm_io_bus_read(struct kvm_vcpu *vcpu, enum kvm_bus bus_idx, gpa_t addr,
5530 		    int len, void *val)
5531 {
5532 	struct kvm_io_bus *bus;
5533 	struct kvm_io_range range;
5534 	int r;
5535 
5536 	range = (struct kvm_io_range) {
5537 		.addr = addr,
5538 		.len = len,
5539 	};
5540 
5541 	bus = srcu_dereference(vcpu->kvm->buses[bus_idx], &vcpu->kvm->srcu);
5542 	if (!bus)
5543 		return -ENOMEM;
5544 	r = __kvm_io_bus_read(vcpu, bus, &range, val);
5545 	return r < 0 ? r : 0;
5546 }
5547 
5548 /* Caller must hold slots_lock. */
kvm_io_bus_register_dev(struct kvm * kvm,enum kvm_bus bus_idx,gpa_t addr,int len,struct kvm_io_device * dev)5549 int kvm_io_bus_register_dev(struct kvm *kvm, enum kvm_bus bus_idx, gpa_t addr,
5550 			    int len, struct kvm_io_device *dev)
5551 {
5552 	int i;
5553 	struct kvm_io_bus *new_bus, *bus;
5554 	struct kvm_io_range range;
5555 
5556 	bus = kvm_get_bus(kvm, bus_idx);
5557 	if (!bus)
5558 		return -ENOMEM;
5559 
5560 	/* exclude ioeventfd which is limited by maximum fd */
5561 	if (bus->dev_count - bus->ioeventfd_count > NR_IOBUS_DEVS - 1)
5562 		return -ENOSPC;
5563 
5564 	new_bus = kmalloc(struct_size(bus, range, bus->dev_count + 1),
5565 			  GFP_KERNEL_ACCOUNT);
5566 	if (!new_bus)
5567 		return -ENOMEM;
5568 
5569 	range = (struct kvm_io_range) {
5570 		.addr = addr,
5571 		.len = len,
5572 		.dev = dev,
5573 	};
5574 
5575 	for (i = 0; i < bus->dev_count; i++)
5576 		if (kvm_io_bus_cmp(&bus->range[i], &range) > 0)
5577 			break;
5578 
5579 	memcpy(new_bus, bus, sizeof(*bus) + i * sizeof(struct kvm_io_range));
5580 	new_bus->dev_count++;
5581 	new_bus->range[i] = range;
5582 	memcpy(new_bus->range + i + 1, bus->range + i,
5583 		(bus->dev_count - i) * sizeof(struct kvm_io_range));
5584 	rcu_assign_pointer(kvm->buses[bus_idx], new_bus);
5585 	synchronize_srcu_expedited(&kvm->srcu);
5586 	kfree(bus);
5587 
5588 	return 0;
5589 }
5590 
kvm_io_bus_unregister_dev(struct kvm * kvm,enum kvm_bus bus_idx,struct kvm_io_device * dev)5591 int kvm_io_bus_unregister_dev(struct kvm *kvm, enum kvm_bus bus_idx,
5592 			      struct kvm_io_device *dev)
5593 {
5594 	int i;
5595 	struct kvm_io_bus *new_bus, *bus;
5596 
5597 	lockdep_assert_held(&kvm->slots_lock);
5598 
5599 	bus = kvm_get_bus(kvm, bus_idx);
5600 	if (!bus)
5601 		return 0;
5602 
5603 	for (i = 0; i < bus->dev_count; i++) {
5604 		if (bus->range[i].dev == dev) {
5605 			break;
5606 		}
5607 	}
5608 
5609 	if (i == bus->dev_count)
5610 		return 0;
5611 
5612 	new_bus = kmalloc(struct_size(bus, range, bus->dev_count - 1),
5613 			  GFP_KERNEL_ACCOUNT);
5614 	if (new_bus) {
5615 		memcpy(new_bus, bus, struct_size(bus, range, i));
5616 		new_bus->dev_count--;
5617 		memcpy(new_bus->range + i, bus->range + i + 1,
5618 				flex_array_size(new_bus, range, new_bus->dev_count - i));
5619 	}
5620 
5621 	rcu_assign_pointer(kvm->buses[bus_idx], new_bus);
5622 	synchronize_srcu_expedited(&kvm->srcu);
5623 
5624 	/*
5625 	 * If NULL bus is installed, destroy the old bus, including all the
5626 	 * attached devices. Otherwise, destroy the caller's device only.
5627 	 */
5628 	if (!new_bus) {
5629 		pr_err("kvm: failed to shrink bus, removing it completely\n");
5630 		kvm_io_bus_destroy(bus);
5631 		return -ENOMEM;
5632 	}
5633 
5634 	kvm_iodevice_destructor(dev);
5635 	kfree(bus);
5636 	return 0;
5637 }
5638 
kvm_io_bus_get_dev(struct kvm * kvm,enum kvm_bus bus_idx,gpa_t addr)5639 struct kvm_io_device *kvm_io_bus_get_dev(struct kvm *kvm, enum kvm_bus bus_idx,
5640 					 gpa_t addr)
5641 {
5642 	struct kvm_io_bus *bus;
5643 	int dev_idx, srcu_idx;
5644 	struct kvm_io_device *iodev = NULL;
5645 
5646 	srcu_idx = srcu_read_lock(&kvm->srcu);
5647 
5648 	bus = srcu_dereference(kvm->buses[bus_idx], &kvm->srcu);
5649 	if (!bus)
5650 		goto out_unlock;
5651 
5652 	dev_idx = kvm_io_bus_get_first_dev(bus, addr, 1);
5653 	if (dev_idx < 0)
5654 		goto out_unlock;
5655 
5656 	iodev = bus->range[dev_idx].dev;
5657 
5658 out_unlock:
5659 	srcu_read_unlock(&kvm->srcu, srcu_idx);
5660 
5661 	return iodev;
5662 }
5663 EXPORT_SYMBOL_GPL(kvm_io_bus_get_dev);
5664 
kvm_debugfs_open(struct inode * inode,struct file * file,int (* get)(void *,u64 *),int (* set)(void *,u64),const char * fmt)5665 static int kvm_debugfs_open(struct inode *inode, struct file *file,
5666 			   int (*get)(void *, u64 *), int (*set)(void *, u64),
5667 			   const char *fmt)
5668 {
5669 	int ret;
5670 	struct kvm_stat_data *stat_data = inode->i_private;
5671 
5672 	/*
5673 	 * The debugfs files are a reference to the kvm struct which
5674         * is still valid when kvm_destroy_vm is called.  kvm_get_kvm_safe
5675         * avoids the race between open and the removal of the debugfs directory.
5676 	 */
5677 	if (!kvm_get_kvm_safe(stat_data->kvm))
5678 		return -ENOENT;
5679 
5680 	ret = simple_attr_open(inode, file, get,
5681 			       kvm_stats_debugfs_mode(stat_data->desc) & 0222
5682 			       ? set : NULL, fmt);
5683 	if (ret)
5684 		kvm_put_kvm(stat_data->kvm);
5685 
5686 	return ret;
5687 }
5688 
kvm_debugfs_release(struct inode * inode,struct file * file)5689 static int kvm_debugfs_release(struct inode *inode, struct file *file)
5690 {
5691 	struct kvm_stat_data *stat_data = inode->i_private;
5692 
5693 	simple_attr_release(inode, file);
5694 	kvm_put_kvm(stat_data->kvm);
5695 
5696 	return 0;
5697 }
5698 
kvm_get_stat_per_vm(struct kvm * kvm,size_t offset,u64 * val)5699 static int kvm_get_stat_per_vm(struct kvm *kvm, size_t offset, u64 *val)
5700 {
5701 	*val = *(u64 *)((void *)(&kvm->stat) + offset);
5702 
5703 	return 0;
5704 }
5705 
kvm_clear_stat_per_vm(struct kvm * kvm,size_t offset)5706 static int kvm_clear_stat_per_vm(struct kvm *kvm, size_t offset)
5707 {
5708 	*(u64 *)((void *)(&kvm->stat) + offset) = 0;
5709 
5710 	return 0;
5711 }
5712 
kvm_get_stat_per_vcpu(struct kvm * kvm,size_t offset,u64 * val)5713 static int kvm_get_stat_per_vcpu(struct kvm *kvm, size_t offset, u64 *val)
5714 {
5715 	unsigned long i;
5716 	struct kvm_vcpu *vcpu;
5717 
5718 	*val = 0;
5719 
5720 	kvm_for_each_vcpu(i, vcpu, kvm)
5721 		*val += *(u64 *)((void *)(&vcpu->stat) + offset);
5722 
5723 	return 0;
5724 }
5725 
kvm_clear_stat_per_vcpu(struct kvm * kvm,size_t offset)5726 static int kvm_clear_stat_per_vcpu(struct kvm *kvm, size_t offset)
5727 {
5728 	unsigned long i;
5729 	struct kvm_vcpu *vcpu;
5730 
5731 	kvm_for_each_vcpu(i, vcpu, kvm)
5732 		*(u64 *)((void *)(&vcpu->stat) + offset) = 0;
5733 
5734 	return 0;
5735 }
5736 
kvm_stat_data_get(void * data,u64 * val)5737 static int kvm_stat_data_get(void *data, u64 *val)
5738 {
5739 	int r = -EFAULT;
5740 	struct kvm_stat_data *stat_data = data;
5741 
5742 	switch (stat_data->kind) {
5743 	case KVM_STAT_VM:
5744 		r = kvm_get_stat_per_vm(stat_data->kvm,
5745 					stat_data->desc->desc.offset, val);
5746 		break;
5747 	case KVM_STAT_VCPU:
5748 		r = kvm_get_stat_per_vcpu(stat_data->kvm,
5749 					  stat_data->desc->desc.offset, val);
5750 		break;
5751 	}
5752 
5753 	return r;
5754 }
5755 
kvm_stat_data_clear(void * data,u64 val)5756 static int kvm_stat_data_clear(void *data, u64 val)
5757 {
5758 	int r = -EFAULT;
5759 	struct kvm_stat_data *stat_data = data;
5760 
5761 	if (val)
5762 		return -EINVAL;
5763 
5764 	switch (stat_data->kind) {
5765 	case KVM_STAT_VM:
5766 		r = kvm_clear_stat_per_vm(stat_data->kvm,
5767 					  stat_data->desc->desc.offset);
5768 		break;
5769 	case KVM_STAT_VCPU:
5770 		r = kvm_clear_stat_per_vcpu(stat_data->kvm,
5771 					    stat_data->desc->desc.offset);
5772 		break;
5773 	}
5774 
5775 	return r;
5776 }
5777 
kvm_stat_data_open(struct inode * inode,struct file * file)5778 static int kvm_stat_data_open(struct inode *inode, struct file *file)
5779 {
5780 	__simple_attr_check_format("%llu\n", 0ull);
5781 	return kvm_debugfs_open(inode, file, kvm_stat_data_get,
5782 				kvm_stat_data_clear, "%llu\n");
5783 }
5784 
5785 static const struct file_operations stat_fops_per_vm = {
5786 	.owner = THIS_MODULE,
5787 	.open = kvm_stat_data_open,
5788 	.release = kvm_debugfs_release,
5789 	.read = simple_attr_read,
5790 	.write = simple_attr_write,
5791 	.llseek = no_llseek,
5792 };
5793 
vm_stat_get(void * _offset,u64 * val)5794 static int vm_stat_get(void *_offset, u64 *val)
5795 {
5796 	unsigned offset = (long)_offset;
5797 	struct kvm *kvm;
5798 	u64 tmp_val;
5799 
5800 	*val = 0;
5801 	mutex_lock(&kvm_lock);
5802 	list_for_each_entry(kvm, &vm_list, vm_list) {
5803 		kvm_get_stat_per_vm(kvm, offset, &tmp_val);
5804 		*val += tmp_val;
5805 	}
5806 	mutex_unlock(&kvm_lock);
5807 	return 0;
5808 }
5809 
vm_stat_clear(void * _offset,u64 val)5810 static int vm_stat_clear(void *_offset, u64 val)
5811 {
5812 	unsigned offset = (long)_offset;
5813 	struct kvm *kvm;
5814 
5815 	if (val)
5816 		return -EINVAL;
5817 
5818 	mutex_lock(&kvm_lock);
5819 	list_for_each_entry(kvm, &vm_list, vm_list) {
5820 		kvm_clear_stat_per_vm(kvm, offset);
5821 	}
5822 	mutex_unlock(&kvm_lock);
5823 
5824 	return 0;
5825 }
5826 
5827 DEFINE_SIMPLE_ATTRIBUTE(vm_stat_fops, vm_stat_get, vm_stat_clear, "%llu\n");
5828 DEFINE_SIMPLE_ATTRIBUTE(vm_stat_readonly_fops, vm_stat_get, NULL, "%llu\n");
5829 
vcpu_stat_get(void * _offset,u64 * val)5830 static int vcpu_stat_get(void *_offset, u64 *val)
5831 {
5832 	unsigned offset = (long)_offset;
5833 	struct kvm *kvm;
5834 	u64 tmp_val;
5835 
5836 	*val = 0;
5837 	mutex_lock(&kvm_lock);
5838 	list_for_each_entry(kvm, &vm_list, vm_list) {
5839 		kvm_get_stat_per_vcpu(kvm, offset, &tmp_val);
5840 		*val += tmp_val;
5841 	}
5842 	mutex_unlock(&kvm_lock);
5843 	return 0;
5844 }
5845 
vcpu_stat_clear(void * _offset,u64 val)5846 static int vcpu_stat_clear(void *_offset, u64 val)
5847 {
5848 	unsigned offset = (long)_offset;
5849 	struct kvm *kvm;
5850 
5851 	if (val)
5852 		return -EINVAL;
5853 
5854 	mutex_lock(&kvm_lock);
5855 	list_for_each_entry(kvm, &vm_list, vm_list) {
5856 		kvm_clear_stat_per_vcpu(kvm, offset);
5857 	}
5858 	mutex_unlock(&kvm_lock);
5859 
5860 	return 0;
5861 }
5862 
5863 DEFINE_SIMPLE_ATTRIBUTE(vcpu_stat_fops, vcpu_stat_get, vcpu_stat_clear,
5864 			"%llu\n");
5865 DEFINE_SIMPLE_ATTRIBUTE(vcpu_stat_readonly_fops, vcpu_stat_get, NULL, "%llu\n");
5866 
kvm_uevent_notify_change(unsigned int type,struct kvm * kvm)5867 static void kvm_uevent_notify_change(unsigned int type, struct kvm *kvm)
5868 {
5869 	struct kobj_uevent_env *env;
5870 	unsigned long long created, active;
5871 
5872 	if (!kvm_dev.this_device || !kvm)
5873 		return;
5874 
5875 	mutex_lock(&kvm_lock);
5876 	if (type == KVM_EVENT_CREATE_VM) {
5877 		kvm_createvm_count++;
5878 		kvm_active_vms++;
5879 	} else if (type == KVM_EVENT_DESTROY_VM) {
5880 		kvm_active_vms--;
5881 	}
5882 	created = kvm_createvm_count;
5883 	active = kvm_active_vms;
5884 	mutex_unlock(&kvm_lock);
5885 
5886 	env = kzalloc(sizeof(*env), GFP_KERNEL_ACCOUNT);
5887 	if (!env)
5888 		return;
5889 
5890 	add_uevent_var(env, "CREATED=%llu", created);
5891 	add_uevent_var(env, "COUNT=%llu", active);
5892 
5893 	if (type == KVM_EVENT_CREATE_VM) {
5894 		add_uevent_var(env, "EVENT=create");
5895 		kvm->userspace_pid = task_pid_nr(current);
5896 	} else if (type == KVM_EVENT_DESTROY_VM) {
5897 		add_uevent_var(env, "EVENT=destroy");
5898 	}
5899 	add_uevent_var(env, "PID=%d", kvm->userspace_pid);
5900 
5901 	if (!IS_ERR(kvm->debugfs_dentry)) {
5902 		char *tmp, *p = kmalloc(PATH_MAX, GFP_KERNEL_ACCOUNT);
5903 
5904 		if (p) {
5905 			tmp = dentry_path_raw(kvm->debugfs_dentry, p, PATH_MAX);
5906 			if (!IS_ERR(tmp))
5907 				add_uevent_var(env, "STATS_PATH=%s", tmp);
5908 			kfree(p);
5909 		}
5910 	}
5911 	/* no need for checks, since we are adding at most only 5 keys */
5912 	env->envp[env->envp_idx++] = NULL;
5913 	kobject_uevent_env(&kvm_dev.this_device->kobj, KOBJ_CHANGE, env->envp);
5914 	kfree(env);
5915 }
5916 
kvm_init_debug(void)5917 static void kvm_init_debug(void)
5918 {
5919 	const struct file_operations *fops;
5920 	const struct _kvm_stats_desc *pdesc;
5921 	int i;
5922 
5923 	kvm_debugfs_dir = debugfs_create_dir("kvm", NULL);
5924 
5925 	for (i = 0; i < kvm_vm_stats_header.num_desc; ++i) {
5926 		pdesc = &kvm_vm_stats_desc[i];
5927 		if (kvm_stats_debugfs_mode(pdesc) & 0222)
5928 			fops = &vm_stat_fops;
5929 		else
5930 			fops = &vm_stat_readonly_fops;
5931 		debugfs_create_file(pdesc->name, kvm_stats_debugfs_mode(pdesc),
5932 				kvm_debugfs_dir,
5933 				(void *)(long)pdesc->desc.offset, fops);
5934 	}
5935 
5936 	for (i = 0; i < kvm_vcpu_stats_header.num_desc; ++i) {
5937 		pdesc = &kvm_vcpu_stats_desc[i];
5938 		if (kvm_stats_debugfs_mode(pdesc) & 0222)
5939 			fops = &vcpu_stat_fops;
5940 		else
5941 			fops = &vcpu_stat_readonly_fops;
5942 		debugfs_create_file(pdesc->name, kvm_stats_debugfs_mode(pdesc),
5943 				kvm_debugfs_dir,
5944 				(void *)(long)pdesc->desc.offset, fops);
5945 	}
5946 }
5947 
5948 static inline
preempt_notifier_to_vcpu(struct preempt_notifier * pn)5949 struct kvm_vcpu *preempt_notifier_to_vcpu(struct preempt_notifier *pn)
5950 {
5951 	return container_of(pn, struct kvm_vcpu, preempt_notifier);
5952 }
5953 
kvm_sched_in(struct preempt_notifier * pn,int cpu)5954 static void kvm_sched_in(struct preempt_notifier *pn, int cpu)
5955 {
5956 	struct kvm_vcpu *vcpu = preempt_notifier_to_vcpu(pn);
5957 
5958 	WRITE_ONCE(vcpu->preempted, false);
5959 	WRITE_ONCE(vcpu->ready, false);
5960 
5961 	__this_cpu_write(kvm_running_vcpu, vcpu);
5962 	kvm_arch_sched_in(vcpu, cpu);
5963 	kvm_arch_vcpu_load(vcpu, cpu);
5964 }
5965 
kvm_sched_out(struct preempt_notifier * pn,struct task_struct * next)5966 static void kvm_sched_out(struct preempt_notifier *pn,
5967 			  struct task_struct *next)
5968 {
5969 	struct kvm_vcpu *vcpu = preempt_notifier_to_vcpu(pn);
5970 
5971 	if (current->on_rq) {
5972 		WRITE_ONCE(vcpu->preempted, true);
5973 		WRITE_ONCE(vcpu->ready, true);
5974 	}
5975 	kvm_arch_vcpu_put(vcpu);
5976 	__this_cpu_write(kvm_running_vcpu, NULL);
5977 }
5978 
5979 /**
5980  * kvm_get_running_vcpu - get the vcpu running on the current CPU.
5981  *
5982  * We can disable preemption locally around accessing the per-CPU variable,
5983  * and use the resolved vcpu pointer after enabling preemption again,
5984  * because even if the current thread is migrated to another CPU, reading
5985  * the per-CPU value later will give us the same value as we update the
5986  * per-CPU variable in the preempt notifier handlers.
5987  */
kvm_get_running_vcpu(void)5988 struct kvm_vcpu *kvm_get_running_vcpu(void)
5989 {
5990 	struct kvm_vcpu *vcpu;
5991 
5992 	preempt_disable();
5993 	vcpu = __this_cpu_read(kvm_running_vcpu);
5994 	preempt_enable();
5995 
5996 	return vcpu;
5997 }
5998 EXPORT_SYMBOL_GPL(kvm_get_running_vcpu);
5999 
6000 /**
6001  * kvm_get_running_vcpus - get the per-CPU array of currently running vcpus.
6002  */
kvm_get_running_vcpus(void)6003 struct kvm_vcpu * __percpu *kvm_get_running_vcpus(void)
6004 {
6005         return &kvm_running_vcpu;
6006 }
6007 
6008 #ifdef CONFIG_GUEST_PERF_EVENTS
kvm_guest_state(void)6009 static unsigned int kvm_guest_state(void)
6010 {
6011 	struct kvm_vcpu *vcpu = kvm_get_running_vcpu();
6012 	unsigned int state;
6013 
6014 	if (!kvm_arch_pmi_in_guest(vcpu))
6015 		return 0;
6016 
6017 	state = PERF_GUEST_ACTIVE;
6018 	if (!kvm_arch_vcpu_in_kernel(vcpu))
6019 		state |= PERF_GUEST_USER;
6020 
6021 	return state;
6022 }
6023 
kvm_guest_get_ip(void)6024 static unsigned long kvm_guest_get_ip(void)
6025 {
6026 	struct kvm_vcpu *vcpu = kvm_get_running_vcpu();
6027 
6028 	/* Retrieving the IP must be guarded by a call to kvm_guest_state(). */
6029 	if (WARN_ON_ONCE(!kvm_arch_pmi_in_guest(vcpu)))
6030 		return 0;
6031 
6032 	return kvm_arch_vcpu_get_ip(vcpu);
6033 }
6034 
6035 static struct perf_guest_info_callbacks kvm_guest_cbs = {
6036 	.state			= kvm_guest_state,
6037 	.get_ip			= kvm_guest_get_ip,
6038 	.handle_intel_pt_intr	= NULL,
6039 };
6040 
kvm_register_perf_callbacks(unsigned int (* pt_intr_handler)(void))6041 void kvm_register_perf_callbacks(unsigned int (*pt_intr_handler)(void))
6042 {
6043 	kvm_guest_cbs.handle_intel_pt_intr = pt_intr_handler;
6044 	perf_register_guest_info_callbacks(&kvm_guest_cbs);
6045 }
kvm_unregister_perf_callbacks(void)6046 void kvm_unregister_perf_callbacks(void)
6047 {
6048 	perf_unregister_guest_info_callbacks(&kvm_guest_cbs);
6049 }
6050 #endif
6051 
kvm_init(unsigned vcpu_size,unsigned vcpu_align,struct module * module)6052 int kvm_init(unsigned vcpu_size, unsigned vcpu_align, struct module *module)
6053 {
6054 	int r;
6055 	int cpu;
6056 
6057 #ifdef CONFIG_KVM_GENERIC_HARDWARE_ENABLING
6058 	r = cpuhp_setup_state_nocalls(CPUHP_AP_KVM_ONLINE, "kvm/cpu:online",
6059 				      kvm_online_cpu, kvm_offline_cpu);
6060 	if (r)
6061 		return r;
6062 
6063 	register_syscore_ops(&kvm_syscore_ops);
6064 #endif
6065 
6066 	/* A kmem cache lets us meet the alignment requirements of fx_save. */
6067 	if (!vcpu_align)
6068 		vcpu_align = __alignof__(struct kvm_vcpu);
6069 	kvm_vcpu_cache =
6070 		kmem_cache_create_usercopy("kvm_vcpu", vcpu_size, vcpu_align,
6071 					   SLAB_ACCOUNT,
6072 					   offsetof(struct kvm_vcpu, arch),
6073 					   offsetofend(struct kvm_vcpu, stats_id)
6074 					   - offsetof(struct kvm_vcpu, arch),
6075 					   NULL);
6076 	if (!kvm_vcpu_cache) {
6077 		r = -ENOMEM;
6078 		goto err_vcpu_cache;
6079 	}
6080 
6081 	for_each_possible_cpu(cpu) {
6082 		if (!alloc_cpumask_var_node(&per_cpu(cpu_kick_mask, cpu),
6083 					    GFP_KERNEL, cpu_to_node(cpu))) {
6084 			r = -ENOMEM;
6085 			goto err_cpu_kick_mask;
6086 		}
6087 	}
6088 
6089 	r = kvm_irqfd_init();
6090 	if (r)
6091 		goto err_irqfd;
6092 
6093 	r = kvm_async_pf_init();
6094 	if (r)
6095 		goto err_async_pf;
6096 
6097 	kvm_chardev_ops.owner = module;
6098 
6099 	kvm_preempt_ops.sched_in = kvm_sched_in;
6100 	kvm_preempt_ops.sched_out = kvm_sched_out;
6101 
6102 	kvm_init_debug();
6103 
6104 	r = kvm_vfio_ops_init();
6105 	if (WARN_ON_ONCE(r))
6106 		goto err_vfio;
6107 
6108 	/*
6109 	 * Registration _must_ be the very last thing done, as this exposes
6110 	 * /dev/kvm to userspace, i.e. all infrastructure must be setup!
6111 	 */
6112 	r = misc_register(&kvm_dev);
6113 	if (r) {
6114 		pr_err("kvm: misc device register failed\n");
6115 		goto err_register;
6116 	}
6117 
6118 	return 0;
6119 
6120 err_register:
6121 	kvm_vfio_ops_exit();
6122 err_vfio:
6123 	kvm_async_pf_deinit();
6124 err_async_pf:
6125 	kvm_irqfd_exit();
6126 err_irqfd:
6127 err_cpu_kick_mask:
6128 	for_each_possible_cpu(cpu)
6129 		free_cpumask_var(per_cpu(cpu_kick_mask, cpu));
6130 	kmem_cache_destroy(kvm_vcpu_cache);
6131 err_vcpu_cache:
6132 #ifdef CONFIG_KVM_GENERIC_HARDWARE_ENABLING
6133 	unregister_syscore_ops(&kvm_syscore_ops);
6134 	cpuhp_remove_state_nocalls(CPUHP_AP_KVM_ONLINE);
6135 #endif
6136 	return r;
6137 }
6138 EXPORT_SYMBOL_GPL(kvm_init);
6139 
kvm_exit(void)6140 void kvm_exit(void)
6141 {
6142 	int cpu;
6143 
6144 	/*
6145 	 * Note, unregistering /dev/kvm doesn't strictly need to come first,
6146 	 * fops_get(), a.k.a. try_module_get(), prevents acquiring references
6147 	 * to KVM while the module is being stopped.
6148 	 */
6149 	misc_deregister(&kvm_dev);
6150 
6151 	debugfs_remove_recursive(kvm_debugfs_dir);
6152 	for_each_possible_cpu(cpu)
6153 		free_cpumask_var(per_cpu(cpu_kick_mask, cpu));
6154 	kmem_cache_destroy(kvm_vcpu_cache);
6155 	kvm_vfio_ops_exit();
6156 	kvm_async_pf_deinit();
6157 #ifdef CONFIG_KVM_GENERIC_HARDWARE_ENABLING
6158 	unregister_syscore_ops(&kvm_syscore_ops);
6159 	cpuhp_remove_state_nocalls(CPUHP_AP_KVM_ONLINE);
6160 #endif
6161 	kvm_irqfd_exit();
6162 }
6163 EXPORT_SYMBOL_GPL(kvm_exit);
6164 
6165 struct kvm_vm_worker_thread_context {
6166 	struct kvm *kvm;
6167 	struct task_struct *parent;
6168 	struct completion init_done;
6169 	kvm_vm_thread_fn_t thread_fn;
6170 	uintptr_t data;
6171 	int err;
6172 };
6173 
kvm_vm_worker_thread(void * context)6174 static int kvm_vm_worker_thread(void *context)
6175 {
6176 	/*
6177 	 * The init_context is allocated on the stack of the parent thread, so
6178 	 * we have to locally copy anything that is needed beyond initialization
6179 	 */
6180 	struct kvm_vm_worker_thread_context *init_context = context;
6181 	struct task_struct *parent;
6182 	struct kvm *kvm = init_context->kvm;
6183 	kvm_vm_thread_fn_t thread_fn = init_context->thread_fn;
6184 	uintptr_t data = init_context->data;
6185 	int err;
6186 
6187 	err = kthread_park(current);
6188 	/* kthread_park(current) is never supposed to return an error */
6189 	WARN_ON(err != 0);
6190 	if (err)
6191 		goto init_complete;
6192 
6193 	err = cgroup_attach_task_all(init_context->parent, current);
6194 	if (err) {
6195 		kvm_err("%s: cgroup_attach_task_all failed with err %d\n",
6196 			__func__, err);
6197 		goto init_complete;
6198 	}
6199 
6200 	set_user_nice(current, task_nice(init_context->parent));
6201 
6202 init_complete:
6203 	init_context->err = err;
6204 	complete(&init_context->init_done);
6205 	init_context = NULL;
6206 
6207 	if (err)
6208 		goto out;
6209 
6210 	/* Wait to be woken up by the spawner before proceeding. */
6211 	kthread_parkme();
6212 
6213 	if (!kthread_should_stop())
6214 		err = thread_fn(kvm, data);
6215 
6216 out:
6217 	/*
6218 	 * Move kthread back to its original cgroup to prevent it lingering in
6219 	 * the cgroup of the VM process, after the latter finishes its
6220 	 * execution.
6221 	 *
6222 	 * kthread_stop() waits on the 'exited' completion condition which is
6223 	 * set in exit_mm(), via mm_release(), in do_exit(). However, the
6224 	 * kthread is removed from the cgroup in the cgroup_exit() which is
6225 	 * called after the exit_mm(). This causes the kthread_stop() to return
6226 	 * before the kthread actually quits the cgroup.
6227 	 */
6228 	rcu_read_lock();
6229 	parent = rcu_dereference(current->real_parent);
6230 	get_task_struct(parent);
6231 	rcu_read_unlock();
6232 	cgroup_attach_task_all(parent, current);
6233 	put_task_struct(parent);
6234 
6235 	return err;
6236 }
6237 
kvm_vm_create_worker_thread(struct kvm * kvm,kvm_vm_thread_fn_t thread_fn,uintptr_t data,const char * name,struct task_struct ** thread_ptr)6238 int kvm_vm_create_worker_thread(struct kvm *kvm, kvm_vm_thread_fn_t thread_fn,
6239 				uintptr_t data, const char *name,
6240 				struct task_struct **thread_ptr)
6241 {
6242 	struct kvm_vm_worker_thread_context init_context = {};
6243 	struct task_struct *thread;
6244 
6245 	*thread_ptr = NULL;
6246 	init_context.kvm = kvm;
6247 	init_context.parent = current;
6248 	init_context.thread_fn = thread_fn;
6249 	init_context.data = data;
6250 	init_completion(&init_context.init_done);
6251 
6252 	thread = kthread_run(kvm_vm_worker_thread, &init_context,
6253 			     "%s-%d", name, task_pid_nr(current));
6254 	if (IS_ERR(thread))
6255 		return PTR_ERR(thread);
6256 
6257 	/* kthread_run is never supposed to return NULL */
6258 	WARN_ON(thread == NULL);
6259 
6260 	wait_for_completion(&init_context.init_done);
6261 
6262 	if (!init_context.err)
6263 		*thread_ptr = thread;
6264 
6265 	return init_context.err;
6266 }
6267