1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright (C) 2012 - Virtual Open Systems and Columbia University
4  * Author: Christoffer Dall <c.dall@virtualopensystems.com>
5  */
6 
7 #include <linux/mman.h>
8 #include <linux/kvm_host.h>
9 #include <linux/io.h>
10 #include <linux/hugetlb.h>
11 #include <linux/sched/signal.h>
12 #include <trace/events/kvm.h>
13 #include <asm/pgalloc.h>
14 #include <asm/cacheflush.h>
15 #include <asm/kvm_arm.h>
16 #include <asm/kvm_mmu.h>
17 #include <asm/kvm_pgtable.h>
18 #include <asm/kvm_ras.h>
19 #include <asm/kvm_asm.h>
20 #include <asm/kvm_emulate.h>
21 #include <asm/virt.h>
22 
23 #include "trace.h"
24 
25 static struct kvm_pgtable *hyp_pgtable;
26 static DEFINE_MUTEX(kvm_hyp_pgd_mutex);
27 
28 static unsigned long hyp_idmap_start;
29 static unsigned long hyp_idmap_end;
30 static phys_addr_t hyp_idmap_vector;
31 
32 static unsigned long io_map_base;
33 
34 
35 /*
36  * Release kvm_mmu_lock periodically if the memory region is large. Otherwise,
37  * we may see kernel panics with CONFIG_DETECT_HUNG_TASK,
38  * CONFIG_LOCKUP_DETECTOR, CONFIG_LOCKDEP. Additionally, holding the lock too
39  * long will also starve other vCPUs. We have to also make sure that the page
40  * tables are not freed while we released the lock.
41  */
stage2_apply_range(struct kvm * kvm,phys_addr_t addr,phys_addr_t end,int (* fn)(struct kvm_pgtable *,u64,u64),bool resched)42 static int stage2_apply_range(struct kvm *kvm, phys_addr_t addr,
43 			      phys_addr_t end,
44 			      int (*fn)(struct kvm_pgtable *, u64, u64),
45 			      bool resched)
46 {
47 	int ret;
48 	u64 next;
49 
50 	do {
51 		struct kvm_pgtable *pgt = kvm->arch.mmu.pgt;
52 		if (!pgt)
53 			return -EINVAL;
54 
55 		next = stage2_pgd_addr_end(kvm, addr, end);
56 		ret = fn(pgt, addr, next - addr);
57 		if (ret)
58 			break;
59 
60 		if (resched && next != end)
61 			cond_resched_rwlock_write(&kvm->mmu_lock);
62 	} while (addr = next, addr != end);
63 
64 	return ret;
65 }
66 
67 #define stage2_apply_range_resched(kvm, addr, end, fn)			\
68 	stage2_apply_range(kvm, addr, end, fn, true)
69 
memslot_is_logging(struct kvm_memory_slot * memslot)70 static bool memslot_is_logging(struct kvm_memory_slot *memslot)
71 {
72 	return memslot->dirty_bitmap && !(memslot->flags & KVM_MEM_READONLY);
73 }
74 
75 /**
76  * kvm_flush_remote_tlbs() - flush all VM TLB entries for v7/8
77  * @kvm:	pointer to kvm structure.
78  *
79  * Interface to HYP function to flush all VM TLB entries
80  */
kvm_flush_remote_tlbs(struct kvm * kvm)81 void kvm_flush_remote_tlbs(struct kvm *kvm)
82 {
83 	++kvm->stat.generic.remote_tlb_flush_requests;
84 	kvm_call_hyp(__kvm_tlb_flush_vmid, &kvm->arch.mmu);
85 }
86 
kvm_is_device_pfn(unsigned long pfn)87 static bool kvm_is_device_pfn(unsigned long pfn)
88 {
89 	return !pfn_is_map_memory(pfn);
90 }
91 
stage2_memcache_zalloc_page(void * arg)92 static void *stage2_memcache_zalloc_page(void *arg)
93 {
94 	struct kvm_mmu_memory_cache *mc = arg;
95 
96 	/* Allocated with __GFP_ZERO, so no need to zero */
97 	return kvm_mmu_memory_cache_alloc(mc);
98 }
99 
kvm_host_zalloc_pages_exact(size_t size)100 static void *kvm_host_zalloc_pages_exact(size_t size)
101 {
102 	return alloc_pages_exact(size, GFP_KERNEL_ACCOUNT | __GFP_ZERO);
103 }
104 
kvm_host_get_page(void * addr)105 static void kvm_host_get_page(void *addr)
106 {
107 	get_page(virt_to_page(addr));
108 }
109 
kvm_host_put_page(void * addr)110 static void kvm_host_put_page(void *addr)
111 {
112 	put_page(virt_to_page(addr));
113 }
114 
kvm_host_page_count(void * addr)115 static int kvm_host_page_count(void *addr)
116 {
117 	return page_count(virt_to_page(addr));
118 }
119 
kvm_host_pa(void * addr)120 static phys_addr_t kvm_host_pa(void *addr)
121 {
122 	return __pa(addr);
123 }
124 
kvm_host_va(phys_addr_t phys)125 static void *kvm_host_va(phys_addr_t phys)
126 {
127 	return __va(phys);
128 }
129 
clean_dcache_guest_page(void * va,size_t size)130 static void clean_dcache_guest_page(void *va, size_t size)
131 {
132 	__clean_dcache_guest_page(va, size);
133 }
134 
invalidate_icache_guest_page(void * va,size_t size)135 static void invalidate_icache_guest_page(void *va, size_t size)
136 {
137 	__invalidate_icache_guest_page(va, size);
138 }
139 
140 /*
141  * Unmapping vs dcache management:
142  *
143  * If a guest maps certain memory pages as uncached, all writes will
144  * bypass the data cache and go directly to RAM.  However, the CPUs
145  * can still speculate reads (not writes) and fill cache lines with
146  * data.
147  *
148  * Those cache lines will be *clean* cache lines though, so a
149  * clean+invalidate operation is equivalent to an invalidate
150  * operation, because no cache lines are marked dirty.
151  *
152  * Those clean cache lines could be filled prior to an uncached write
153  * by the guest, and the cache coherent IO subsystem would therefore
154  * end up writing old data to disk.
155  *
156  * This is why right after unmapping a page/section and invalidating
157  * the corresponding TLBs, we flush to make sure the IO subsystem will
158  * never hit in the cache.
159  *
160  * This is all avoided on systems that have ARM64_HAS_STAGE2_FWB, as
161  * we then fully enforce cacheability of RAM, no matter what the guest
162  * does.
163  */
164 /**
165  * unmap_stage2_range -- Clear stage2 page table entries to unmap a range
166  * @mmu:   The KVM stage-2 MMU pointer
167  * @start: The intermediate physical base address of the range to unmap
168  * @size:  The size of the area to unmap
169  * @may_block: Whether or not we are permitted to block
170  *
171  * Clear a range of stage-2 mappings, lowering the various ref-counts.  Must
172  * be called while holding mmu_lock (unless for freeing the stage2 pgd before
173  * destroying the VM), otherwise another faulting VCPU may come in and mess
174  * with things behind our backs.
175  */
__unmap_stage2_range(struct kvm_s2_mmu * mmu,phys_addr_t start,u64 size,bool may_block)176 static void __unmap_stage2_range(struct kvm_s2_mmu *mmu, phys_addr_t start, u64 size,
177 				 bool may_block)
178 {
179 	struct kvm *kvm = kvm_s2_mmu_to_kvm(mmu);
180 	phys_addr_t end = start + size;
181 
182 	lockdep_assert_held_write(&kvm->mmu_lock);
183 	WARN_ON(size & ~PAGE_MASK);
184 	WARN_ON(stage2_apply_range(kvm, start, end, kvm_pgtable_stage2_unmap,
185 				   may_block));
186 }
187 
unmap_stage2_range(struct kvm_s2_mmu * mmu,phys_addr_t start,u64 size)188 static void unmap_stage2_range(struct kvm_s2_mmu *mmu, phys_addr_t start, u64 size)
189 {
190 	__unmap_stage2_range(mmu, start, size, true);
191 }
192 
stage2_flush_memslot(struct kvm * kvm,struct kvm_memory_slot * memslot)193 static void stage2_flush_memslot(struct kvm *kvm,
194 				 struct kvm_memory_slot *memslot)
195 {
196 	phys_addr_t addr = memslot->base_gfn << PAGE_SHIFT;
197 	phys_addr_t end = addr + PAGE_SIZE * memslot->npages;
198 
199 	stage2_apply_range_resched(kvm, addr, end, kvm_pgtable_stage2_flush);
200 }
201 
202 /**
203  * stage2_flush_vm - Invalidate cache for pages mapped in stage 2
204  * @kvm: The struct kvm pointer
205  *
206  * Go through the stage 2 page tables and invalidate any cache lines
207  * backing memory already mapped to the VM.
208  */
stage2_flush_vm(struct kvm * kvm)209 static void stage2_flush_vm(struct kvm *kvm)
210 {
211 	struct kvm_memslots *slots;
212 	struct kvm_memory_slot *memslot;
213 	int idx, bkt;
214 
215 	idx = srcu_read_lock(&kvm->srcu);
216 	write_lock(&kvm->mmu_lock);
217 
218 	slots = kvm_memslots(kvm);
219 	kvm_for_each_memslot(memslot, bkt, slots)
220 		stage2_flush_memslot(kvm, memslot);
221 
222 	write_unlock(&kvm->mmu_lock);
223 	srcu_read_unlock(&kvm->srcu, idx);
224 }
225 
226 /**
227  * free_hyp_pgds - free Hyp-mode page tables
228  */
free_hyp_pgds(void)229 void free_hyp_pgds(void)
230 {
231 	mutex_lock(&kvm_hyp_pgd_mutex);
232 	if (hyp_pgtable) {
233 		kvm_pgtable_hyp_destroy(hyp_pgtable);
234 		kfree(hyp_pgtable);
235 		hyp_pgtable = NULL;
236 	}
237 	mutex_unlock(&kvm_hyp_pgd_mutex);
238 }
239 
kvm_host_owns_hyp_mappings(void)240 static bool kvm_host_owns_hyp_mappings(void)
241 {
242 	if (is_kernel_in_hyp_mode())
243 		return false;
244 
245 	if (static_branch_likely(&kvm_protected_mode_initialized))
246 		return false;
247 
248 	/*
249 	 * This can happen at boot time when __create_hyp_mappings() is called
250 	 * after the hyp protection has been enabled, but the static key has
251 	 * not been flipped yet.
252 	 */
253 	if (!hyp_pgtable && is_protected_kvm_enabled())
254 		return false;
255 
256 	WARN_ON(!hyp_pgtable);
257 
258 	return true;
259 }
260 
__create_hyp_mappings(unsigned long start,unsigned long size,unsigned long phys,enum kvm_pgtable_prot prot)261 int __create_hyp_mappings(unsigned long start, unsigned long size,
262 			  unsigned long phys, enum kvm_pgtable_prot prot)
263 {
264 	int err;
265 
266 	if (WARN_ON(!kvm_host_owns_hyp_mappings()))
267 		return -EINVAL;
268 
269 	mutex_lock(&kvm_hyp_pgd_mutex);
270 	err = kvm_pgtable_hyp_map(hyp_pgtable, start, size, phys, prot);
271 	mutex_unlock(&kvm_hyp_pgd_mutex);
272 
273 	return err;
274 }
275 
kvm_kaddr_to_phys(void * kaddr)276 static phys_addr_t kvm_kaddr_to_phys(void *kaddr)
277 {
278 	if (!is_vmalloc_addr(kaddr)) {
279 		BUG_ON(!virt_addr_valid(kaddr));
280 		return __pa(kaddr);
281 	} else {
282 		return page_to_phys(vmalloc_to_page(kaddr)) +
283 		       offset_in_page(kaddr);
284 	}
285 }
286 
287 struct hyp_shared_pfn {
288 	u64 pfn;
289 	int count;
290 	struct rb_node node;
291 };
292 
293 static DEFINE_MUTEX(hyp_shared_pfns_lock);
294 static struct rb_root hyp_shared_pfns = RB_ROOT;
295 
find_shared_pfn(u64 pfn,struct rb_node *** node,struct rb_node ** parent)296 static struct hyp_shared_pfn *find_shared_pfn(u64 pfn, struct rb_node ***node,
297 					      struct rb_node **parent)
298 {
299 	struct hyp_shared_pfn *this;
300 
301 	*node = &hyp_shared_pfns.rb_node;
302 	*parent = NULL;
303 	while (**node) {
304 		this = container_of(**node, struct hyp_shared_pfn, node);
305 		*parent = **node;
306 		if (this->pfn < pfn)
307 			*node = &((**node)->rb_left);
308 		else if (this->pfn > pfn)
309 			*node = &((**node)->rb_right);
310 		else
311 			return this;
312 	}
313 
314 	return NULL;
315 }
316 
share_pfn_hyp(u64 pfn)317 static int share_pfn_hyp(u64 pfn)
318 {
319 	struct rb_node **node, *parent;
320 	struct hyp_shared_pfn *this;
321 	int ret = 0;
322 
323 	mutex_lock(&hyp_shared_pfns_lock);
324 	this = find_shared_pfn(pfn, &node, &parent);
325 	if (this) {
326 		this->count++;
327 		goto unlock;
328 	}
329 
330 	this = kzalloc(sizeof(*this), GFP_KERNEL);
331 	if (!this) {
332 		ret = -ENOMEM;
333 		goto unlock;
334 	}
335 
336 	this->pfn = pfn;
337 	this->count = 1;
338 	rb_link_node(&this->node, parent, node);
339 	rb_insert_color(&this->node, &hyp_shared_pfns);
340 	ret = kvm_call_hyp_nvhe(__pkvm_host_share_hyp, pfn, 1);
341 unlock:
342 	mutex_unlock(&hyp_shared_pfns_lock);
343 
344 	return ret;
345 }
346 
unshare_pfn_hyp(u64 pfn)347 static int unshare_pfn_hyp(u64 pfn)
348 {
349 	struct rb_node **node, *parent;
350 	struct hyp_shared_pfn *this;
351 	int ret = 0;
352 
353 	mutex_lock(&hyp_shared_pfns_lock);
354 	this = find_shared_pfn(pfn, &node, &parent);
355 	if (WARN_ON(!this)) {
356 		ret = -ENOENT;
357 		goto unlock;
358 	}
359 
360 	this->count--;
361 	if (this->count)
362 		goto unlock;
363 
364 	rb_erase(&this->node, &hyp_shared_pfns);
365 	kfree(this);
366 	ret = kvm_call_hyp_nvhe(__pkvm_host_unshare_hyp, pfn, 1);
367 unlock:
368 	mutex_unlock(&hyp_shared_pfns_lock);
369 
370 	return ret;
371 }
372 
kvm_share_hyp(void * from,void * to)373 int kvm_share_hyp(void *from, void *to)
374 {
375 	phys_addr_t start, end, cur;
376 	u64 pfn;
377 	int ret;
378 
379 	if (is_kernel_in_hyp_mode())
380 		return 0;
381 
382 	/*
383 	 * The share hcall maps things in the 'fixed-offset' region of the hyp
384 	 * VA space, so we can only share physically contiguous data-structures
385 	 * for now.
386 	 */
387 	if (is_vmalloc_or_module_addr(from) || is_vmalloc_or_module_addr(to))
388 		return -EINVAL;
389 
390 	if (kvm_host_owns_hyp_mappings())
391 		return create_hyp_mappings(from, to, PAGE_HYP);
392 
393 	start = ALIGN_DOWN(__pa(from), PAGE_SIZE);
394 	end = PAGE_ALIGN(__pa(to));
395 	for (cur = start; cur < end; cur += PAGE_SIZE) {
396 		pfn = __phys_to_pfn(cur);
397 		ret = share_pfn_hyp(pfn);
398 		if (ret)
399 			return ret;
400 	}
401 
402 	return 0;
403 }
404 
kvm_unshare_hyp(void * from,void * to)405 void kvm_unshare_hyp(void *from, void *to)
406 {
407 	phys_addr_t start, end, cur;
408 	u64 pfn;
409 
410 	if (is_kernel_in_hyp_mode() || kvm_host_owns_hyp_mappings() || !from)
411 		return;
412 
413 	start = ALIGN_DOWN(__pa(from), PAGE_SIZE);
414 	end = PAGE_ALIGN(__pa(to));
415 	for (cur = start; cur < end; cur += PAGE_SIZE) {
416 		pfn = __phys_to_pfn(cur);
417 		WARN_ON(unshare_pfn_hyp(pfn));
418 	}
419 }
420 
421 /**
422  * create_hyp_mappings - duplicate a kernel virtual address range in Hyp mode
423  * @from:	The virtual kernel start address of the range
424  * @to:		The virtual kernel end address of the range (exclusive)
425  * @prot:	The protection to be applied to this range
426  *
427  * The same virtual address as the kernel virtual address is also used
428  * in Hyp-mode mapping (modulo HYP_PAGE_OFFSET) to the same underlying
429  * physical pages.
430  */
create_hyp_mappings(void * from,void * to,enum kvm_pgtable_prot prot)431 int create_hyp_mappings(void *from, void *to, enum kvm_pgtable_prot prot)
432 {
433 	phys_addr_t phys_addr;
434 	unsigned long virt_addr;
435 	unsigned long start = kern_hyp_va((unsigned long)from);
436 	unsigned long end = kern_hyp_va((unsigned long)to);
437 
438 	if (is_kernel_in_hyp_mode())
439 		return 0;
440 
441 	if (!kvm_host_owns_hyp_mappings())
442 		return -EPERM;
443 
444 	start = start & PAGE_MASK;
445 	end = PAGE_ALIGN(end);
446 
447 	for (virt_addr = start; virt_addr < end; virt_addr += PAGE_SIZE) {
448 		int err;
449 
450 		phys_addr = kvm_kaddr_to_phys(from + virt_addr - start);
451 		err = __create_hyp_mappings(virt_addr, PAGE_SIZE, phys_addr,
452 					    prot);
453 		if (err)
454 			return err;
455 	}
456 
457 	return 0;
458 }
459 
460 
461 /**
462  * hyp_alloc_private_va_range - Allocates a private VA range.
463  * @size:	The size of the VA range to reserve.
464  * @haddr:	The hypervisor virtual start address of the allocation.
465  *
466  * The private virtual address (VA) range is allocated below io_map_base
467  * and aligned based on the order of @size.
468  *
469  * Return: 0 on success or negative error code on failure.
470  */
hyp_alloc_private_va_range(size_t size,unsigned long * haddr)471 int hyp_alloc_private_va_range(size_t size, unsigned long *haddr)
472 {
473 	unsigned long base;
474 	int ret = 0;
475 
476 	mutex_lock(&kvm_hyp_pgd_mutex);
477 
478 	/*
479 	 * This assumes that we have enough space below the idmap
480 	 * page to allocate our VAs. If not, the check below will
481 	 * kick. A potential alternative would be to detect that
482 	 * overflow and switch to an allocation above the idmap.
483 	 *
484 	 * The allocated size is always a multiple of PAGE_SIZE.
485 	 */
486 	base = io_map_base - PAGE_ALIGN(size);
487 
488 	/* Align the allocation based on the order of its size */
489 	base = ALIGN_DOWN(base, PAGE_SIZE << get_order(size));
490 
491 	/*
492 	 * Verify that BIT(VA_BITS - 1) hasn't been flipped by
493 	 * allocating the new area, as it would indicate we've
494 	 * overflowed the idmap/IO address range.
495 	 */
496 	if ((base ^ io_map_base) & BIT(VA_BITS - 1))
497 		ret = -ENOMEM;
498 	else
499 		*haddr = io_map_base = base;
500 
501 	mutex_unlock(&kvm_hyp_pgd_mutex);
502 
503 	return ret;
504 }
505 
__create_hyp_private_mapping(phys_addr_t phys_addr,size_t size,unsigned long * haddr,enum kvm_pgtable_prot prot)506 static int __create_hyp_private_mapping(phys_addr_t phys_addr, size_t size,
507 					unsigned long *haddr,
508 					enum kvm_pgtable_prot prot)
509 {
510 	unsigned long addr;
511 	int ret = 0;
512 
513 	if (!kvm_host_owns_hyp_mappings()) {
514 		addr = kvm_call_hyp_nvhe(__pkvm_create_private_mapping,
515 					 phys_addr, size, prot);
516 		if (IS_ERR_VALUE(addr))
517 			return addr;
518 		*haddr = addr;
519 
520 		return 0;
521 	}
522 
523 	size = PAGE_ALIGN(size + offset_in_page(phys_addr));
524 	ret = hyp_alloc_private_va_range(size, &addr);
525 	if (ret)
526 		return ret;
527 
528 	ret = __create_hyp_mappings(addr, size, phys_addr, prot);
529 	if (ret)
530 		return ret;
531 
532 	*haddr = addr + offset_in_page(phys_addr);
533 	return ret;
534 }
535 
536 /**
537  * create_hyp_io_mappings - Map IO into both kernel and HYP
538  * @phys_addr:	The physical start address which gets mapped
539  * @size:	Size of the region being mapped
540  * @kaddr:	Kernel VA for this mapping
541  * @haddr:	HYP VA for this mapping
542  */
create_hyp_io_mappings(phys_addr_t phys_addr,size_t size,void __iomem ** kaddr,void __iomem ** haddr)543 int create_hyp_io_mappings(phys_addr_t phys_addr, size_t size,
544 			   void __iomem **kaddr,
545 			   void __iomem **haddr)
546 {
547 	unsigned long addr;
548 	int ret;
549 
550 	if (is_protected_kvm_enabled())
551 		return -EPERM;
552 
553 	*kaddr = ioremap(phys_addr, size);
554 	if (!*kaddr)
555 		return -ENOMEM;
556 
557 	if (is_kernel_in_hyp_mode()) {
558 		*haddr = *kaddr;
559 		return 0;
560 	}
561 
562 	ret = __create_hyp_private_mapping(phys_addr, size,
563 					   &addr, PAGE_HYP_DEVICE);
564 	if (ret) {
565 		iounmap(*kaddr);
566 		*kaddr = NULL;
567 		*haddr = NULL;
568 		return ret;
569 	}
570 
571 	*haddr = (void __iomem *)addr;
572 	return 0;
573 }
574 
575 /**
576  * create_hyp_exec_mappings - Map an executable range into HYP
577  * @phys_addr:	The physical start address which gets mapped
578  * @size:	Size of the region being mapped
579  * @haddr:	HYP VA for this mapping
580  */
create_hyp_exec_mappings(phys_addr_t phys_addr,size_t size,void ** haddr)581 int create_hyp_exec_mappings(phys_addr_t phys_addr, size_t size,
582 			     void **haddr)
583 {
584 	unsigned long addr;
585 	int ret;
586 
587 	BUG_ON(is_kernel_in_hyp_mode());
588 
589 	ret = __create_hyp_private_mapping(phys_addr, size,
590 					   &addr, PAGE_HYP_EXEC);
591 	if (ret) {
592 		*haddr = NULL;
593 		return ret;
594 	}
595 
596 	*haddr = (void *)addr;
597 	return 0;
598 }
599 
600 static struct kvm_pgtable_mm_ops kvm_user_mm_ops = {
601 	/* We shouldn't need any other callback to walk the PT */
602 	.phys_to_virt		= kvm_host_va,
603 };
604 
get_user_mapping_size(struct kvm * kvm,u64 addr)605 static int get_user_mapping_size(struct kvm *kvm, u64 addr)
606 {
607 	struct kvm_pgtable pgt = {
608 		.pgd		= (kvm_pte_t *)kvm->mm->pgd,
609 		.ia_bits	= VA_BITS,
610 		.start_level	= (KVM_PGTABLE_MAX_LEVELS -
611 				   CONFIG_PGTABLE_LEVELS),
612 		.mm_ops		= &kvm_user_mm_ops,
613 	};
614 	kvm_pte_t pte = 0;	/* Keep GCC quiet... */
615 	u32 level = ~0;
616 	int ret;
617 
618 	ret = kvm_pgtable_get_leaf(&pgt, addr, &pte, &level);
619 	VM_BUG_ON(ret);
620 	VM_BUG_ON(level >= KVM_PGTABLE_MAX_LEVELS);
621 	VM_BUG_ON(!(pte & PTE_VALID));
622 
623 	return BIT(ARM64_HW_PGTABLE_LEVEL_SHIFT(level));
624 }
625 
626 static struct kvm_pgtable_mm_ops kvm_s2_mm_ops = {
627 	.zalloc_page		= stage2_memcache_zalloc_page,
628 	.zalloc_pages_exact	= kvm_host_zalloc_pages_exact,
629 	.free_pages_exact	= free_pages_exact,
630 	.get_page		= kvm_host_get_page,
631 	.put_page		= kvm_host_put_page,
632 	.page_count		= kvm_host_page_count,
633 	.phys_to_virt		= kvm_host_va,
634 	.virt_to_phys		= kvm_host_pa,
635 	.dcache_clean_inval_poc	= clean_dcache_guest_page,
636 	.icache_inval_pou	= invalidate_icache_guest_page,
637 };
638 
639 /**
640  * kvm_init_stage2_mmu - Initialise a S2 MMU structure
641  * @kvm:	The pointer to the KVM structure
642  * @mmu:	The pointer to the s2 MMU structure
643  *
644  * Allocates only the stage-2 HW PGD level table(s).
645  * Note we don't need locking here as this is only called when the VM is
646  * created, which can only be done once.
647  */
kvm_init_stage2_mmu(struct kvm * kvm,struct kvm_s2_mmu * mmu)648 int kvm_init_stage2_mmu(struct kvm *kvm, struct kvm_s2_mmu *mmu)
649 {
650 	int cpu, err;
651 	struct kvm_pgtable *pgt;
652 
653 	if (mmu->pgt != NULL) {
654 		kvm_err("kvm_arch already initialized?\n");
655 		return -EINVAL;
656 	}
657 
658 	pgt = kzalloc(sizeof(*pgt), GFP_KERNEL_ACCOUNT);
659 	if (!pgt)
660 		return -ENOMEM;
661 
662 	mmu->arch = &kvm->arch;
663 	err = kvm_pgtable_stage2_init(pgt, mmu, &kvm_s2_mm_ops);
664 	if (err)
665 		goto out_free_pgtable;
666 
667 	mmu->last_vcpu_ran = alloc_percpu(typeof(*mmu->last_vcpu_ran));
668 	if (!mmu->last_vcpu_ran) {
669 		err = -ENOMEM;
670 		goto out_destroy_pgtable;
671 	}
672 
673 	for_each_possible_cpu(cpu)
674 		*per_cpu_ptr(mmu->last_vcpu_ran, cpu) = -1;
675 
676 	mmu->pgt = pgt;
677 	mmu->pgd_phys = __pa(pgt->pgd);
678 	return 0;
679 
680 out_destroy_pgtable:
681 	kvm_pgtable_stage2_destroy(pgt);
682 out_free_pgtable:
683 	kfree(pgt);
684 	return err;
685 }
686 
stage2_unmap_memslot(struct kvm * kvm,struct kvm_memory_slot * memslot)687 static void stage2_unmap_memslot(struct kvm *kvm,
688 				 struct kvm_memory_slot *memslot)
689 {
690 	hva_t hva = memslot->userspace_addr;
691 	phys_addr_t addr = memslot->base_gfn << PAGE_SHIFT;
692 	phys_addr_t size = PAGE_SIZE * memslot->npages;
693 	hva_t reg_end = hva + size;
694 
695 	/*
696 	 * A memory region could potentially cover multiple VMAs, and any holes
697 	 * between them, so iterate over all of them to find out if we should
698 	 * unmap any of them.
699 	 *
700 	 *     +--------------------------------------------+
701 	 * +---------------+----------------+   +----------------+
702 	 * |   : VMA 1     |      VMA 2     |   |    VMA 3  :    |
703 	 * +---------------+----------------+   +----------------+
704 	 *     |               memory region                |
705 	 *     +--------------------------------------------+
706 	 */
707 	do {
708 		struct vm_area_struct *vma;
709 		hva_t vm_start, vm_end;
710 
711 		vma = find_vma_intersection(current->mm, hva, reg_end);
712 		if (!vma)
713 			break;
714 
715 		/*
716 		 * Take the intersection of this VMA with the memory region
717 		 */
718 		vm_start = max(hva, vma->vm_start);
719 		vm_end = min(reg_end, vma->vm_end);
720 
721 		if (!(vma->vm_flags & VM_PFNMAP)) {
722 			gpa_t gpa = addr + (vm_start - memslot->userspace_addr);
723 			unmap_stage2_range(&kvm->arch.mmu, gpa, vm_end - vm_start);
724 		}
725 		hva = vm_end;
726 	} while (hva < reg_end);
727 }
728 
729 /**
730  * stage2_unmap_vm - Unmap Stage-2 RAM mappings
731  * @kvm: The struct kvm pointer
732  *
733  * Go through the memregions and unmap any regular RAM
734  * backing memory already mapped to the VM.
735  */
stage2_unmap_vm(struct kvm * kvm)736 void stage2_unmap_vm(struct kvm *kvm)
737 {
738 	struct kvm_memslots *slots;
739 	struct kvm_memory_slot *memslot;
740 	int idx, bkt;
741 
742 	idx = srcu_read_lock(&kvm->srcu);
743 	mmap_read_lock(current->mm);
744 	write_lock(&kvm->mmu_lock);
745 
746 	slots = kvm_memslots(kvm);
747 	kvm_for_each_memslot(memslot, bkt, slots)
748 		stage2_unmap_memslot(kvm, memslot);
749 
750 	write_unlock(&kvm->mmu_lock);
751 	mmap_read_unlock(current->mm);
752 	srcu_read_unlock(&kvm->srcu, idx);
753 }
754 
kvm_free_stage2_pgd(struct kvm_s2_mmu * mmu)755 void kvm_free_stage2_pgd(struct kvm_s2_mmu *mmu)
756 {
757 	struct kvm *kvm = kvm_s2_mmu_to_kvm(mmu);
758 	struct kvm_pgtable *pgt = NULL;
759 
760 	write_lock(&kvm->mmu_lock);
761 	pgt = mmu->pgt;
762 	if (pgt) {
763 		mmu->pgd_phys = 0;
764 		mmu->pgt = NULL;
765 		free_percpu(mmu->last_vcpu_ran);
766 	}
767 	write_unlock(&kvm->mmu_lock);
768 
769 	if (pgt) {
770 		kvm_pgtable_stage2_destroy(pgt);
771 		kfree(pgt);
772 	}
773 }
774 
775 /**
776  * kvm_phys_addr_ioremap - map a device range to guest IPA
777  *
778  * @kvm:	The KVM pointer
779  * @guest_ipa:	The IPA at which to insert the mapping
780  * @pa:		The physical address of the device
781  * @size:	The size of the mapping
782  * @writable:   Whether or not to create a writable mapping
783  */
kvm_phys_addr_ioremap(struct kvm * kvm,phys_addr_t guest_ipa,phys_addr_t pa,unsigned long size,bool writable)784 int kvm_phys_addr_ioremap(struct kvm *kvm, phys_addr_t guest_ipa,
785 			  phys_addr_t pa, unsigned long size, bool writable)
786 {
787 	phys_addr_t addr;
788 	int ret = 0;
789 	struct kvm_mmu_memory_cache cache = { 0, __GFP_ZERO, NULL, };
790 	struct kvm_pgtable *pgt = kvm->arch.mmu.pgt;
791 	enum kvm_pgtable_prot prot = KVM_PGTABLE_PROT_DEVICE |
792 				     KVM_PGTABLE_PROT_R |
793 				     (writable ? KVM_PGTABLE_PROT_W : 0);
794 
795 	if (is_protected_kvm_enabled())
796 		return -EPERM;
797 
798 	size += offset_in_page(guest_ipa);
799 	guest_ipa &= PAGE_MASK;
800 
801 	for (addr = guest_ipa; addr < guest_ipa + size; addr += PAGE_SIZE) {
802 		ret = kvm_mmu_topup_memory_cache(&cache,
803 						 kvm_mmu_cache_min_pages(kvm));
804 		if (ret)
805 			break;
806 
807 		write_lock(&kvm->mmu_lock);
808 		ret = kvm_pgtable_stage2_map(pgt, addr, PAGE_SIZE, pa, prot,
809 					     &cache);
810 		write_unlock(&kvm->mmu_lock);
811 		if (ret)
812 			break;
813 
814 		pa += PAGE_SIZE;
815 	}
816 
817 	kvm_mmu_free_memory_cache(&cache);
818 	return ret;
819 }
820 
821 /**
822  * stage2_wp_range() - write protect stage2 memory region range
823  * @mmu:        The KVM stage-2 MMU pointer
824  * @addr:	Start address of range
825  * @end:	End address of range
826  */
stage2_wp_range(struct kvm_s2_mmu * mmu,phys_addr_t addr,phys_addr_t end)827 static void stage2_wp_range(struct kvm_s2_mmu *mmu, phys_addr_t addr, phys_addr_t end)
828 {
829 	struct kvm *kvm = kvm_s2_mmu_to_kvm(mmu);
830 	stage2_apply_range_resched(kvm, addr, end, kvm_pgtable_stage2_wrprotect);
831 }
832 
833 /**
834  * kvm_mmu_wp_memory_region() - write protect stage 2 entries for memory slot
835  * @kvm:	The KVM pointer
836  * @slot:	The memory slot to write protect
837  *
838  * Called to start logging dirty pages after memory region
839  * KVM_MEM_LOG_DIRTY_PAGES operation is called. After this function returns
840  * all present PUD, PMD and PTEs are write protected in the memory region.
841  * Afterwards read of dirty page log can be called.
842  *
843  * Acquires kvm_mmu_lock. Called with kvm->slots_lock mutex acquired,
844  * serializing operations for VM memory regions.
845  */
kvm_mmu_wp_memory_region(struct kvm * kvm,int slot)846 static void kvm_mmu_wp_memory_region(struct kvm *kvm, int slot)
847 {
848 	struct kvm_memslots *slots = kvm_memslots(kvm);
849 	struct kvm_memory_slot *memslot = id_to_memslot(slots, slot);
850 	phys_addr_t start, end;
851 
852 	if (WARN_ON_ONCE(!memslot))
853 		return;
854 
855 	start = memslot->base_gfn << PAGE_SHIFT;
856 	end = (memslot->base_gfn + memslot->npages) << PAGE_SHIFT;
857 
858 	write_lock(&kvm->mmu_lock);
859 	stage2_wp_range(&kvm->arch.mmu, start, end);
860 	write_unlock(&kvm->mmu_lock);
861 	kvm_flush_remote_tlbs(kvm);
862 }
863 
864 /**
865  * kvm_mmu_write_protect_pt_masked() - write protect dirty pages
866  * @kvm:	The KVM pointer
867  * @slot:	The memory slot associated with mask
868  * @gfn_offset:	The gfn offset in memory slot
869  * @mask:	The mask of dirty pages at offset 'gfn_offset' in this memory
870  *		slot to be write protected
871  *
872  * Walks bits set in mask write protects the associated pte's. Caller must
873  * acquire kvm_mmu_lock.
874  */
kvm_mmu_write_protect_pt_masked(struct kvm * kvm,struct kvm_memory_slot * slot,gfn_t gfn_offset,unsigned long mask)875 static void kvm_mmu_write_protect_pt_masked(struct kvm *kvm,
876 		struct kvm_memory_slot *slot,
877 		gfn_t gfn_offset, unsigned long mask)
878 {
879 	phys_addr_t base_gfn = slot->base_gfn + gfn_offset;
880 	phys_addr_t start = (base_gfn +  __ffs(mask)) << PAGE_SHIFT;
881 	phys_addr_t end = (base_gfn + __fls(mask) + 1) << PAGE_SHIFT;
882 
883 	stage2_wp_range(&kvm->arch.mmu, start, end);
884 }
885 
886 /*
887  * kvm_arch_mmu_enable_log_dirty_pt_masked - enable dirty logging for selected
888  * dirty pages.
889  *
890  * It calls kvm_mmu_write_protect_pt_masked to write protect selected pages to
891  * enable dirty logging for them.
892  */
kvm_arch_mmu_enable_log_dirty_pt_masked(struct kvm * kvm,struct kvm_memory_slot * slot,gfn_t gfn_offset,unsigned long mask)893 void kvm_arch_mmu_enable_log_dirty_pt_masked(struct kvm *kvm,
894 		struct kvm_memory_slot *slot,
895 		gfn_t gfn_offset, unsigned long mask)
896 {
897 	kvm_mmu_write_protect_pt_masked(kvm, slot, gfn_offset, mask);
898 }
899 
kvm_send_hwpoison_signal(unsigned long address,short lsb)900 static void kvm_send_hwpoison_signal(unsigned long address, short lsb)
901 {
902 	send_sig_mceerr(BUS_MCEERR_AR, (void __user *)address, lsb, current);
903 }
904 
fault_supports_stage2_huge_mapping(struct kvm_memory_slot * memslot,unsigned long hva,unsigned long map_size)905 static bool fault_supports_stage2_huge_mapping(struct kvm_memory_slot *memslot,
906 					       unsigned long hva,
907 					       unsigned long map_size)
908 {
909 	gpa_t gpa_start;
910 	hva_t uaddr_start, uaddr_end;
911 	size_t size;
912 
913 	/* The memslot and the VMA are guaranteed to be aligned to PAGE_SIZE */
914 	if (map_size == PAGE_SIZE)
915 		return true;
916 
917 	size = memslot->npages * PAGE_SIZE;
918 
919 	gpa_start = memslot->base_gfn << PAGE_SHIFT;
920 
921 	uaddr_start = memslot->userspace_addr;
922 	uaddr_end = uaddr_start + size;
923 
924 	/*
925 	 * Pages belonging to memslots that don't have the same alignment
926 	 * within a PMD/PUD for userspace and IPA cannot be mapped with stage-2
927 	 * PMD/PUD entries, because we'll end up mapping the wrong pages.
928 	 *
929 	 * Consider a layout like the following:
930 	 *
931 	 *    memslot->userspace_addr:
932 	 *    +-----+--------------------+--------------------+---+
933 	 *    |abcde|fgh  Stage-1 block  |    Stage-1 block tv|xyz|
934 	 *    +-----+--------------------+--------------------+---+
935 	 *
936 	 *    memslot->base_gfn << PAGE_SHIFT:
937 	 *      +---+--------------------+--------------------+-----+
938 	 *      |abc|def  Stage-2 block  |    Stage-2 block   |tvxyz|
939 	 *      +---+--------------------+--------------------+-----+
940 	 *
941 	 * If we create those stage-2 blocks, we'll end up with this incorrect
942 	 * mapping:
943 	 *   d -> f
944 	 *   e -> g
945 	 *   f -> h
946 	 */
947 	if ((gpa_start & (map_size - 1)) != (uaddr_start & (map_size - 1)))
948 		return false;
949 
950 	/*
951 	 * Next, let's make sure we're not trying to map anything not covered
952 	 * by the memslot. This means we have to prohibit block size mappings
953 	 * for the beginning and end of a non-block aligned and non-block sized
954 	 * memory slot (illustrated by the head and tail parts of the
955 	 * userspace view above containing pages 'abcde' and 'xyz',
956 	 * respectively).
957 	 *
958 	 * Note that it doesn't matter if we do the check using the
959 	 * userspace_addr or the base_gfn, as both are equally aligned (per
960 	 * the check above) and equally sized.
961 	 */
962 	return (hva & ~(map_size - 1)) >= uaddr_start &&
963 	       (hva & ~(map_size - 1)) + map_size <= uaddr_end;
964 }
965 
966 /*
967  * Check if the given hva is backed by a transparent huge page (THP) and
968  * whether it can be mapped using block mapping in stage2. If so, adjust
969  * the stage2 PFN and IPA accordingly. Only PMD_SIZE THPs are currently
970  * supported. This will need to be updated to support other THP sizes.
971  *
972  * Returns the size of the mapping.
973  */
974 static unsigned long
transparent_hugepage_adjust(struct kvm * kvm,struct kvm_memory_slot * memslot,unsigned long hva,kvm_pfn_t * pfnp,phys_addr_t * ipap)975 transparent_hugepage_adjust(struct kvm *kvm, struct kvm_memory_slot *memslot,
976 			    unsigned long hva, kvm_pfn_t *pfnp,
977 			    phys_addr_t *ipap)
978 {
979 	kvm_pfn_t pfn = *pfnp;
980 
981 	/*
982 	 * Make sure the adjustment is done only for THP pages. Also make
983 	 * sure that the HVA and IPA are sufficiently aligned and that the
984 	 * block map is contained within the memslot.
985 	 */
986 	if (fault_supports_stage2_huge_mapping(memslot, hva, PMD_SIZE) &&
987 	    get_user_mapping_size(kvm, hva) >= PMD_SIZE) {
988 		/*
989 		 * The address we faulted on is backed by a transparent huge
990 		 * page.  However, because we map the compound huge page and
991 		 * not the individual tail page, we need to transfer the
992 		 * refcount to the head page.  We have to be careful that the
993 		 * THP doesn't start to split while we are adjusting the
994 		 * refcounts.
995 		 *
996 		 * We are sure this doesn't happen, because mmu_notifier_retry
997 		 * was successful and we are holding the mmu_lock, so if this
998 		 * THP is trying to split, it will be blocked in the mmu
999 		 * notifier before touching any of the pages, specifically
1000 		 * before being able to call __split_huge_page_refcount().
1001 		 *
1002 		 * We can therefore safely transfer the refcount from PG_tail
1003 		 * to PG_head and switch the pfn from a tail page to the head
1004 		 * page accordingly.
1005 		 */
1006 		*ipap &= PMD_MASK;
1007 		kvm_release_pfn_clean(pfn);
1008 		pfn &= ~(PTRS_PER_PMD - 1);
1009 		get_page(pfn_to_page(pfn));
1010 		*pfnp = pfn;
1011 
1012 		return PMD_SIZE;
1013 	}
1014 
1015 	/* Use page mapping if we cannot use block mapping. */
1016 	return PAGE_SIZE;
1017 }
1018 
get_vma_page_shift(struct vm_area_struct * vma,unsigned long hva)1019 static int get_vma_page_shift(struct vm_area_struct *vma, unsigned long hva)
1020 {
1021 	unsigned long pa;
1022 
1023 	if (is_vm_hugetlb_page(vma) && !(vma->vm_flags & VM_PFNMAP))
1024 		return huge_page_shift(hstate_vma(vma));
1025 
1026 	if (!(vma->vm_flags & VM_PFNMAP))
1027 		return PAGE_SHIFT;
1028 
1029 	VM_BUG_ON(is_vm_hugetlb_page(vma));
1030 
1031 	pa = (vma->vm_pgoff << PAGE_SHIFT) + (hva - vma->vm_start);
1032 
1033 #ifndef __PAGETABLE_PMD_FOLDED
1034 	if ((hva & (PUD_SIZE - 1)) == (pa & (PUD_SIZE - 1)) &&
1035 	    ALIGN_DOWN(hva, PUD_SIZE) >= vma->vm_start &&
1036 	    ALIGN(hva, PUD_SIZE) <= vma->vm_end)
1037 		return PUD_SHIFT;
1038 #endif
1039 
1040 	if ((hva & (PMD_SIZE - 1)) == (pa & (PMD_SIZE - 1)) &&
1041 	    ALIGN_DOWN(hva, PMD_SIZE) >= vma->vm_start &&
1042 	    ALIGN(hva, PMD_SIZE) <= vma->vm_end)
1043 		return PMD_SHIFT;
1044 
1045 	return PAGE_SHIFT;
1046 }
1047 
1048 /*
1049  * The page will be mapped in stage 2 as Normal Cacheable, so the VM will be
1050  * able to see the page's tags and therefore they must be initialised first. If
1051  * PG_mte_tagged is set, tags have already been initialised.
1052  *
1053  * The race in the test/set of the PG_mte_tagged flag is handled by:
1054  * - preventing VM_SHARED mappings in a memslot with MTE preventing two VMs
1055  *   racing to santise the same page
1056  * - mmap_lock protects between a VM faulting a page in and the VMM performing
1057  *   an mprotect() to add VM_MTE
1058  */
sanitise_mte_tags(struct kvm * kvm,kvm_pfn_t pfn,unsigned long size)1059 static int sanitise_mte_tags(struct kvm *kvm, kvm_pfn_t pfn,
1060 			     unsigned long size)
1061 {
1062 	unsigned long i, nr_pages = size >> PAGE_SHIFT;
1063 	struct page *page;
1064 
1065 	if (!kvm_has_mte(kvm))
1066 		return 0;
1067 
1068 	/*
1069 	 * pfn_to_online_page() is used to reject ZONE_DEVICE pages
1070 	 * that may not support tags.
1071 	 */
1072 	page = pfn_to_online_page(pfn);
1073 
1074 	if (!page)
1075 		return -EFAULT;
1076 
1077 	for (i = 0; i < nr_pages; i++, page++) {
1078 		if (!test_bit(PG_mte_tagged, &page->flags)) {
1079 			mte_clear_page_tags(page_address(page));
1080 			set_bit(PG_mte_tagged, &page->flags);
1081 		}
1082 	}
1083 
1084 	return 0;
1085 }
1086 
user_mem_abort(struct kvm_vcpu * vcpu,phys_addr_t fault_ipa,struct kvm_memory_slot * memslot,unsigned long hva,unsigned long fault_status)1087 static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
1088 			  struct kvm_memory_slot *memslot, unsigned long hva,
1089 			  unsigned long fault_status)
1090 {
1091 	int ret = 0;
1092 	bool write_fault, writable, force_pte = false;
1093 	bool exec_fault;
1094 	bool device = false;
1095 	bool shared;
1096 	unsigned long mmu_seq;
1097 	struct kvm *kvm = vcpu->kvm;
1098 	struct kvm_mmu_memory_cache *memcache = &vcpu->arch.mmu_page_cache;
1099 	struct vm_area_struct *vma;
1100 	short vma_shift;
1101 	gfn_t gfn;
1102 	kvm_pfn_t pfn;
1103 	bool logging_active = memslot_is_logging(memslot);
1104 	bool use_read_lock = false;
1105 	unsigned long fault_level = kvm_vcpu_trap_get_fault_level(vcpu);
1106 	unsigned long vma_pagesize, fault_granule;
1107 	enum kvm_pgtable_prot prot = KVM_PGTABLE_PROT_R;
1108 	struct kvm_pgtable *pgt;
1109 
1110 	fault_granule = 1UL << ARM64_HW_PGTABLE_LEVEL_SHIFT(fault_level);
1111 	write_fault = kvm_is_write_fault(vcpu);
1112 	exec_fault = kvm_vcpu_trap_is_exec_fault(vcpu);
1113 	VM_BUG_ON(write_fault && exec_fault);
1114 
1115 	if (fault_status == FSC_PERM && !write_fault && !exec_fault) {
1116 		kvm_err("Unexpected L2 read permission error\n");
1117 		return -EFAULT;
1118 	}
1119 
1120 	/*
1121 	 * Let's check if we will get back a huge page backed by hugetlbfs, or
1122 	 * get block mapping for device MMIO region.
1123 	 */
1124 	mmap_read_lock(current->mm);
1125 	vma = vma_lookup(current->mm, hva);
1126 	if (unlikely(!vma)) {
1127 		kvm_err("Failed to find VMA for hva 0x%lx\n", hva);
1128 		mmap_read_unlock(current->mm);
1129 		return -EFAULT;
1130 	}
1131 
1132 	/*
1133 	 * logging_active is guaranteed to never be true for VM_PFNMAP
1134 	 * memslots.
1135 	 */
1136 	if (logging_active) {
1137 		force_pte = true;
1138 		vma_shift = PAGE_SHIFT;
1139 		use_read_lock = (fault_status == FSC_PERM && write_fault &&
1140 				 fault_granule == PAGE_SIZE);
1141 	} else {
1142 		vma_shift = get_vma_page_shift(vma, hva);
1143 	}
1144 
1145 	shared = (vma->vm_flags & VM_SHARED);
1146 
1147 	switch (vma_shift) {
1148 #ifndef __PAGETABLE_PMD_FOLDED
1149 	case PUD_SHIFT:
1150 		if (fault_supports_stage2_huge_mapping(memslot, hva, PUD_SIZE))
1151 			break;
1152 		fallthrough;
1153 #endif
1154 	case CONT_PMD_SHIFT:
1155 		vma_shift = PMD_SHIFT;
1156 		fallthrough;
1157 	case PMD_SHIFT:
1158 		if (fault_supports_stage2_huge_mapping(memslot, hva, PMD_SIZE))
1159 			break;
1160 		fallthrough;
1161 	case CONT_PTE_SHIFT:
1162 		vma_shift = PAGE_SHIFT;
1163 		force_pte = true;
1164 		fallthrough;
1165 	case PAGE_SHIFT:
1166 		break;
1167 	default:
1168 		WARN_ONCE(1, "Unknown vma_shift %d", vma_shift);
1169 	}
1170 
1171 	vma_pagesize = 1UL << vma_shift;
1172 	if (vma_pagesize == PMD_SIZE || vma_pagesize == PUD_SIZE)
1173 		fault_ipa &= ~(vma_pagesize - 1);
1174 
1175 	gfn = fault_ipa >> PAGE_SHIFT;
1176 	mmap_read_unlock(current->mm);
1177 
1178 	/*
1179 	 * Permission faults just need to update the existing leaf entry,
1180 	 * and so normally don't require allocations from the memcache. The
1181 	 * only exception to this is when dirty logging is enabled at runtime
1182 	 * and a write fault needs to collapse a block entry into a table.
1183 	 */
1184 	if (fault_status != FSC_PERM || (logging_active && write_fault)) {
1185 		ret = kvm_mmu_topup_memory_cache(memcache,
1186 						 kvm_mmu_cache_min_pages(kvm));
1187 		if (ret)
1188 			return ret;
1189 	}
1190 
1191 	mmu_seq = vcpu->kvm->mmu_notifier_seq;
1192 	/*
1193 	 * Ensure the read of mmu_notifier_seq happens before we call
1194 	 * gfn_to_pfn_prot (which calls get_user_pages), so that we don't risk
1195 	 * the page we just got a reference to gets unmapped before we have a
1196 	 * chance to grab the mmu_lock, which ensure that if the page gets
1197 	 * unmapped afterwards, the call to kvm_unmap_gfn will take it away
1198 	 * from us again properly. This smp_rmb() interacts with the smp_wmb()
1199 	 * in kvm_mmu_notifier_invalidate_<page|range_end>.
1200 	 *
1201 	 * Besides, __gfn_to_pfn_memslot() instead of gfn_to_pfn_prot() is
1202 	 * used to avoid unnecessary overhead introduced to locate the memory
1203 	 * slot because it's always fixed even @gfn is adjusted for huge pages.
1204 	 */
1205 	smp_rmb();
1206 
1207 	pfn = __gfn_to_pfn_memslot(memslot, gfn, false, NULL,
1208 				   write_fault, &writable, NULL);
1209 	if (pfn == KVM_PFN_ERR_HWPOISON) {
1210 		kvm_send_hwpoison_signal(hva, vma_shift);
1211 		return 0;
1212 	}
1213 	if (is_error_noslot_pfn(pfn))
1214 		return -EFAULT;
1215 
1216 	if (kvm_is_device_pfn(pfn)) {
1217 		/*
1218 		 * If the page was identified as device early by looking at
1219 		 * the VMA flags, vma_pagesize is already representing the
1220 		 * largest quantity we can map.  If instead it was mapped
1221 		 * via gfn_to_pfn_prot(), vma_pagesize is set to PAGE_SIZE
1222 		 * and must not be upgraded.
1223 		 *
1224 		 * In both cases, we don't let transparent_hugepage_adjust()
1225 		 * change things at the last minute.
1226 		 */
1227 		device = true;
1228 	} else if (logging_active && !write_fault) {
1229 		/*
1230 		 * Only actually map the page as writable if this was a write
1231 		 * fault.
1232 		 */
1233 		writable = false;
1234 	}
1235 
1236 	if (exec_fault && device)
1237 		return -ENOEXEC;
1238 
1239 	/*
1240 	 * To reduce MMU contentions and enhance concurrency during dirty
1241 	 * logging dirty logging, only acquire read lock for permission
1242 	 * relaxation.
1243 	 */
1244 	if (use_read_lock)
1245 		read_lock(&kvm->mmu_lock);
1246 	else
1247 		write_lock(&kvm->mmu_lock);
1248 	pgt = vcpu->arch.hw_mmu->pgt;
1249 	if (mmu_notifier_retry(kvm, mmu_seq))
1250 		goto out_unlock;
1251 
1252 	/*
1253 	 * If we are not forced to use page mapping, check if we are
1254 	 * backed by a THP and thus use block mapping if possible.
1255 	 */
1256 	if (vma_pagesize == PAGE_SIZE && !(force_pte || device)) {
1257 		if (fault_status == FSC_PERM && fault_granule > PAGE_SIZE)
1258 			vma_pagesize = fault_granule;
1259 		else
1260 			vma_pagesize = transparent_hugepage_adjust(kvm, memslot,
1261 								   hva, &pfn,
1262 								   &fault_ipa);
1263 	}
1264 
1265 	if (fault_status != FSC_PERM && !device && kvm_has_mte(kvm)) {
1266 		/* Check the VMM hasn't introduced a new VM_SHARED VMA */
1267 		if (!shared)
1268 			ret = sanitise_mte_tags(kvm, pfn, vma_pagesize);
1269 		else
1270 			ret = -EFAULT;
1271 		if (ret)
1272 			goto out_unlock;
1273 	}
1274 
1275 	if (writable)
1276 		prot |= KVM_PGTABLE_PROT_W;
1277 
1278 	if (exec_fault)
1279 		prot |= KVM_PGTABLE_PROT_X;
1280 
1281 	if (device)
1282 		prot |= KVM_PGTABLE_PROT_DEVICE;
1283 	else if (cpus_have_const_cap(ARM64_HAS_CACHE_DIC))
1284 		prot |= KVM_PGTABLE_PROT_X;
1285 
1286 	/*
1287 	 * Under the premise of getting a FSC_PERM fault, we just need to relax
1288 	 * permissions only if vma_pagesize equals fault_granule. Otherwise,
1289 	 * kvm_pgtable_stage2_map() should be called to change block size.
1290 	 */
1291 	if (fault_status == FSC_PERM && vma_pagesize == fault_granule) {
1292 		ret = kvm_pgtable_stage2_relax_perms(pgt, fault_ipa, prot);
1293 	} else {
1294 		WARN_ONCE(use_read_lock, "Attempted stage-2 map outside of write lock\n");
1295 
1296 		ret = kvm_pgtable_stage2_map(pgt, fault_ipa, vma_pagesize,
1297 					     __pfn_to_phys(pfn), prot,
1298 					     memcache);
1299 	}
1300 
1301 	/* Mark the page dirty only if the fault is handled successfully */
1302 	if (writable && !ret) {
1303 		kvm_set_pfn_dirty(pfn);
1304 		mark_page_dirty_in_slot(kvm, memslot, gfn);
1305 	}
1306 
1307 out_unlock:
1308 	if (use_read_lock)
1309 		read_unlock(&kvm->mmu_lock);
1310 	else
1311 		write_unlock(&kvm->mmu_lock);
1312 	kvm_set_pfn_accessed(pfn);
1313 	kvm_release_pfn_clean(pfn);
1314 	return ret != -EAGAIN ? ret : 0;
1315 }
1316 
1317 /* Resolve the access fault by making the page young again. */
handle_access_fault(struct kvm_vcpu * vcpu,phys_addr_t fault_ipa)1318 static void handle_access_fault(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa)
1319 {
1320 	pte_t pte;
1321 	kvm_pte_t kpte;
1322 	struct kvm_s2_mmu *mmu;
1323 
1324 	trace_kvm_access_fault(fault_ipa);
1325 
1326 	write_lock(&vcpu->kvm->mmu_lock);
1327 	mmu = vcpu->arch.hw_mmu;
1328 	kpte = kvm_pgtable_stage2_mkyoung(mmu->pgt, fault_ipa);
1329 	write_unlock(&vcpu->kvm->mmu_lock);
1330 
1331 	pte = __pte(kpte);
1332 	if (pte_valid(pte))
1333 		kvm_set_pfn_accessed(pte_pfn(pte));
1334 }
1335 
1336 /**
1337  * kvm_handle_guest_abort - handles all 2nd stage aborts
1338  * @vcpu:	the VCPU pointer
1339  *
1340  * Any abort that gets to the host is almost guaranteed to be caused by a
1341  * missing second stage translation table entry, which can mean that either the
1342  * guest simply needs more memory and we must allocate an appropriate page or it
1343  * can mean that the guest tried to access I/O memory, which is emulated by user
1344  * space. The distinction is based on the IPA causing the fault and whether this
1345  * memory region has been registered as standard RAM by user space.
1346  */
kvm_handle_guest_abort(struct kvm_vcpu * vcpu)1347 int kvm_handle_guest_abort(struct kvm_vcpu *vcpu)
1348 {
1349 	unsigned long fault_status;
1350 	phys_addr_t fault_ipa;
1351 	struct kvm_memory_slot *memslot;
1352 	unsigned long hva;
1353 	bool is_iabt, write_fault, writable;
1354 	gfn_t gfn;
1355 	int ret, idx;
1356 
1357 	fault_status = kvm_vcpu_trap_get_fault_type(vcpu);
1358 
1359 	fault_ipa = kvm_vcpu_get_fault_ipa(vcpu);
1360 	is_iabt = kvm_vcpu_trap_is_iabt(vcpu);
1361 
1362 	if (fault_status == FSC_FAULT) {
1363 		/* Beyond sanitised PARange (which is the IPA limit) */
1364 		if (fault_ipa >= BIT_ULL(get_kvm_ipa_limit())) {
1365 			kvm_inject_size_fault(vcpu);
1366 			return 1;
1367 		}
1368 
1369 		/* Falls between the IPA range and the PARange? */
1370 		if (fault_ipa >= BIT_ULL(vcpu->arch.hw_mmu->pgt->ia_bits)) {
1371 			fault_ipa |= kvm_vcpu_get_hfar(vcpu) & GENMASK(11, 0);
1372 
1373 			if (is_iabt)
1374 				kvm_inject_pabt(vcpu, fault_ipa);
1375 			else
1376 				kvm_inject_dabt(vcpu, fault_ipa);
1377 			return 1;
1378 		}
1379 	}
1380 
1381 	/* Synchronous External Abort? */
1382 	if (kvm_vcpu_abt_issea(vcpu)) {
1383 		/*
1384 		 * For RAS the host kernel may handle this abort.
1385 		 * There is no need to pass the error into the guest.
1386 		 */
1387 		if (kvm_handle_guest_sea(fault_ipa, kvm_vcpu_get_esr(vcpu)))
1388 			kvm_inject_vabt(vcpu);
1389 
1390 		return 1;
1391 	}
1392 
1393 	trace_kvm_guest_fault(*vcpu_pc(vcpu), kvm_vcpu_get_esr(vcpu),
1394 			      kvm_vcpu_get_hfar(vcpu), fault_ipa);
1395 
1396 	/* Check the stage-2 fault is trans. fault or write fault */
1397 	if (fault_status != FSC_FAULT && fault_status != FSC_PERM &&
1398 	    fault_status != FSC_ACCESS) {
1399 		kvm_err("Unsupported FSC: EC=%#x xFSC=%#lx ESR_EL2=%#lx\n",
1400 			kvm_vcpu_trap_get_class(vcpu),
1401 			(unsigned long)kvm_vcpu_trap_get_fault(vcpu),
1402 			(unsigned long)kvm_vcpu_get_esr(vcpu));
1403 		return -EFAULT;
1404 	}
1405 
1406 	idx = srcu_read_lock(&vcpu->kvm->srcu);
1407 
1408 	gfn = fault_ipa >> PAGE_SHIFT;
1409 	memslot = gfn_to_memslot(vcpu->kvm, gfn);
1410 	hva = gfn_to_hva_memslot_prot(memslot, gfn, &writable);
1411 	write_fault = kvm_is_write_fault(vcpu);
1412 	if (kvm_is_error_hva(hva) || (write_fault && !writable)) {
1413 		/*
1414 		 * The guest has put either its instructions or its page-tables
1415 		 * somewhere it shouldn't have. Userspace won't be able to do
1416 		 * anything about this (there's no syndrome for a start), so
1417 		 * re-inject the abort back into the guest.
1418 		 */
1419 		if (is_iabt) {
1420 			ret = -ENOEXEC;
1421 			goto out;
1422 		}
1423 
1424 		if (kvm_vcpu_abt_iss1tw(vcpu)) {
1425 			kvm_inject_dabt(vcpu, kvm_vcpu_get_hfar(vcpu));
1426 			ret = 1;
1427 			goto out_unlock;
1428 		}
1429 
1430 		/*
1431 		 * Check for a cache maintenance operation. Since we
1432 		 * ended-up here, we know it is outside of any memory
1433 		 * slot. But we can't find out if that is for a device,
1434 		 * or if the guest is just being stupid. The only thing
1435 		 * we know for sure is that this range cannot be cached.
1436 		 *
1437 		 * So let's assume that the guest is just being
1438 		 * cautious, and skip the instruction.
1439 		 */
1440 		if (kvm_is_error_hva(hva) && kvm_vcpu_dabt_is_cm(vcpu)) {
1441 			kvm_incr_pc(vcpu);
1442 			ret = 1;
1443 			goto out_unlock;
1444 		}
1445 
1446 		/*
1447 		 * The IPA is reported as [MAX:12], so we need to
1448 		 * complement it with the bottom 12 bits from the
1449 		 * faulting VA. This is always 12 bits, irrespective
1450 		 * of the page size.
1451 		 */
1452 		fault_ipa |= kvm_vcpu_get_hfar(vcpu) & ((1 << 12) - 1);
1453 		ret = io_mem_abort(vcpu, fault_ipa);
1454 		goto out_unlock;
1455 	}
1456 
1457 	/* Userspace should not be able to register out-of-bounds IPAs */
1458 	VM_BUG_ON(fault_ipa >= kvm_phys_size(vcpu->kvm));
1459 
1460 	if (fault_status == FSC_ACCESS) {
1461 		handle_access_fault(vcpu, fault_ipa);
1462 		ret = 1;
1463 		goto out_unlock;
1464 	}
1465 
1466 	ret = user_mem_abort(vcpu, fault_ipa, memslot, hva, fault_status);
1467 	if (ret == 0)
1468 		ret = 1;
1469 out:
1470 	if (ret == -ENOEXEC) {
1471 		kvm_inject_pabt(vcpu, kvm_vcpu_get_hfar(vcpu));
1472 		ret = 1;
1473 	}
1474 out_unlock:
1475 	srcu_read_unlock(&vcpu->kvm->srcu, idx);
1476 	return ret;
1477 }
1478 
kvm_unmap_gfn_range(struct kvm * kvm,struct kvm_gfn_range * range)1479 bool kvm_unmap_gfn_range(struct kvm *kvm, struct kvm_gfn_range *range)
1480 {
1481 	if (!kvm->arch.mmu.pgt)
1482 		return false;
1483 
1484 	__unmap_stage2_range(&kvm->arch.mmu, range->start << PAGE_SHIFT,
1485 			     (range->end - range->start) << PAGE_SHIFT,
1486 			     range->may_block);
1487 
1488 	return false;
1489 }
1490 
kvm_set_spte_gfn(struct kvm * kvm,struct kvm_gfn_range * range)1491 bool kvm_set_spte_gfn(struct kvm *kvm, struct kvm_gfn_range *range)
1492 {
1493 	kvm_pfn_t pfn = pte_pfn(range->pte);
1494 	int ret;
1495 
1496 	if (!kvm->arch.mmu.pgt)
1497 		return false;
1498 
1499 	WARN_ON(range->end - range->start != 1);
1500 
1501 	ret = sanitise_mte_tags(kvm, pfn, PAGE_SIZE);
1502 	if (ret)
1503 		return false;
1504 
1505 	/*
1506 	 * We've moved a page around, probably through CoW, so let's treat
1507 	 * it just like a translation fault and the map handler will clean
1508 	 * the cache to the PoC.
1509 	 *
1510 	 * The MMU notifiers will have unmapped a huge PMD before calling
1511 	 * ->change_pte() (which in turn calls kvm_set_spte_gfn()) and
1512 	 * therefore we never need to clear out a huge PMD through this
1513 	 * calling path and a memcache is not required.
1514 	 */
1515 	kvm_pgtable_stage2_map(kvm->arch.mmu.pgt, range->start << PAGE_SHIFT,
1516 			       PAGE_SIZE, __pfn_to_phys(pfn),
1517 			       KVM_PGTABLE_PROT_R, NULL);
1518 
1519 	return false;
1520 }
1521 
kvm_age_gfn(struct kvm * kvm,struct kvm_gfn_range * range)1522 bool kvm_age_gfn(struct kvm *kvm, struct kvm_gfn_range *range)
1523 {
1524 	u64 size = (range->end - range->start) << PAGE_SHIFT;
1525 	kvm_pte_t kpte;
1526 	pte_t pte;
1527 
1528 	if (!kvm->arch.mmu.pgt)
1529 		return false;
1530 
1531 	WARN_ON(size != PAGE_SIZE && size != PMD_SIZE && size != PUD_SIZE);
1532 
1533 	kpte = kvm_pgtable_stage2_mkold(kvm->arch.mmu.pgt,
1534 					range->start << PAGE_SHIFT);
1535 	pte = __pte(kpte);
1536 	return pte_valid(pte) && pte_young(pte);
1537 }
1538 
kvm_test_age_gfn(struct kvm * kvm,struct kvm_gfn_range * range)1539 bool kvm_test_age_gfn(struct kvm *kvm, struct kvm_gfn_range *range)
1540 {
1541 	if (!kvm->arch.mmu.pgt)
1542 		return false;
1543 
1544 	return kvm_pgtable_stage2_is_young(kvm->arch.mmu.pgt,
1545 					   range->start << PAGE_SHIFT);
1546 }
1547 
kvm_mmu_get_httbr(void)1548 phys_addr_t kvm_mmu_get_httbr(void)
1549 {
1550 	return __pa(hyp_pgtable->pgd);
1551 }
1552 
kvm_get_idmap_vector(void)1553 phys_addr_t kvm_get_idmap_vector(void)
1554 {
1555 	return hyp_idmap_vector;
1556 }
1557 
kvm_map_idmap_text(void)1558 static int kvm_map_idmap_text(void)
1559 {
1560 	unsigned long size = hyp_idmap_end - hyp_idmap_start;
1561 	int err = __create_hyp_mappings(hyp_idmap_start, size, hyp_idmap_start,
1562 					PAGE_HYP_EXEC);
1563 	if (err)
1564 		kvm_err("Failed to idmap %lx-%lx\n",
1565 			hyp_idmap_start, hyp_idmap_end);
1566 
1567 	return err;
1568 }
1569 
kvm_hyp_zalloc_page(void * arg)1570 static void *kvm_hyp_zalloc_page(void *arg)
1571 {
1572 	return (void *)get_zeroed_page(GFP_KERNEL);
1573 }
1574 
1575 static struct kvm_pgtable_mm_ops kvm_hyp_mm_ops = {
1576 	.zalloc_page		= kvm_hyp_zalloc_page,
1577 	.get_page		= kvm_host_get_page,
1578 	.put_page		= kvm_host_put_page,
1579 	.phys_to_virt		= kvm_host_va,
1580 	.virt_to_phys		= kvm_host_pa,
1581 };
1582 
kvm_mmu_init(u32 * hyp_va_bits)1583 int kvm_mmu_init(u32 *hyp_va_bits)
1584 {
1585 	int err;
1586 
1587 	hyp_idmap_start = __pa_symbol(__hyp_idmap_text_start);
1588 	hyp_idmap_start = ALIGN_DOWN(hyp_idmap_start, PAGE_SIZE);
1589 	hyp_idmap_end = __pa_symbol(__hyp_idmap_text_end);
1590 	hyp_idmap_end = ALIGN(hyp_idmap_end, PAGE_SIZE);
1591 	hyp_idmap_vector = __pa_symbol(__kvm_hyp_init);
1592 
1593 	/*
1594 	 * We rely on the linker script to ensure at build time that the HYP
1595 	 * init code does not cross a page boundary.
1596 	 */
1597 	BUG_ON((hyp_idmap_start ^ (hyp_idmap_end - 1)) & PAGE_MASK);
1598 
1599 	*hyp_va_bits = 64 - ((idmap_t0sz & TCR_T0SZ_MASK) >> TCR_T0SZ_OFFSET);
1600 	kvm_debug("Using %u-bit virtual addresses at EL2\n", *hyp_va_bits);
1601 	kvm_debug("IDMAP page: %lx\n", hyp_idmap_start);
1602 	kvm_debug("HYP VA range: %lx:%lx\n",
1603 		  kern_hyp_va(PAGE_OFFSET),
1604 		  kern_hyp_va((unsigned long)high_memory - 1));
1605 
1606 	if (hyp_idmap_start >= kern_hyp_va(PAGE_OFFSET) &&
1607 	    hyp_idmap_start <  kern_hyp_va((unsigned long)high_memory - 1) &&
1608 	    hyp_idmap_start != (unsigned long)__hyp_idmap_text_start) {
1609 		/*
1610 		 * The idmap page is intersecting with the VA space,
1611 		 * it is not safe to continue further.
1612 		 */
1613 		kvm_err("IDMAP intersecting with HYP VA, unable to continue\n");
1614 		err = -EINVAL;
1615 		goto out;
1616 	}
1617 
1618 	hyp_pgtable = kzalloc(sizeof(*hyp_pgtable), GFP_KERNEL);
1619 	if (!hyp_pgtable) {
1620 		kvm_err("Hyp mode page-table not allocated\n");
1621 		err = -ENOMEM;
1622 		goto out;
1623 	}
1624 
1625 	err = kvm_pgtable_hyp_init(hyp_pgtable, *hyp_va_bits, &kvm_hyp_mm_ops);
1626 	if (err)
1627 		goto out_free_pgtable;
1628 
1629 	err = kvm_map_idmap_text();
1630 	if (err)
1631 		goto out_destroy_pgtable;
1632 
1633 	io_map_base = hyp_idmap_start;
1634 	return 0;
1635 
1636 out_destroy_pgtable:
1637 	kvm_pgtable_hyp_destroy(hyp_pgtable);
1638 out_free_pgtable:
1639 	kfree(hyp_pgtable);
1640 	hyp_pgtable = NULL;
1641 out:
1642 	return err;
1643 }
1644 
kvm_arch_commit_memory_region(struct kvm * kvm,struct kvm_memory_slot * old,const struct kvm_memory_slot * new,enum kvm_mr_change change)1645 void kvm_arch_commit_memory_region(struct kvm *kvm,
1646 				   struct kvm_memory_slot *old,
1647 				   const struct kvm_memory_slot *new,
1648 				   enum kvm_mr_change change)
1649 {
1650 	/*
1651 	 * At this point memslot has been committed and there is an
1652 	 * allocated dirty_bitmap[], dirty pages will be tracked while the
1653 	 * memory slot is write protected.
1654 	 */
1655 	if (change != KVM_MR_DELETE && new->flags & KVM_MEM_LOG_DIRTY_PAGES) {
1656 		/*
1657 		 * If we're with initial-all-set, we don't need to write
1658 		 * protect any pages because they're all reported as dirty.
1659 		 * Huge pages and normal pages will be write protect gradually.
1660 		 */
1661 		if (!kvm_dirty_log_manual_protect_and_init_set(kvm)) {
1662 			kvm_mmu_wp_memory_region(kvm, new->id);
1663 		}
1664 	}
1665 }
1666 
kvm_arch_prepare_memory_region(struct kvm * kvm,const struct kvm_memory_slot * old,struct kvm_memory_slot * new,enum kvm_mr_change change)1667 int kvm_arch_prepare_memory_region(struct kvm *kvm,
1668 				   const struct kvm_memory_slot *old,
1669 				   struct kvm_memory_slot *new,
1670 				   enum kvm_mr_change change)
1671 {
1672 	hva_t hva, reg_end;
1673 	int ret = 0;
1674 
1675 	if (change != KVM_MR_CREATE && change != KVM_MR_MOVE &&
1676 			change != KVM_MR_FLAGS_ONLY)
1677 		return 0;
1678 
1679 	/*
1680 	 * Prevent userspace from creating a memory region outside of the IPA
1681 	 * space addressable by the KVM guest IPA space.
1682 	 */
1683 	if ((new->base_gfn + new->npages) > (kvm_phys_size(kvm) >> PAGE_SHIFT))
1684 		return -EFAULT;
1685 
1686 	hva = new->userspace_addr;
1687 	reg_end = hva + (new->npages << PAGE_SHIFT);
1688 
1689 	mmap_read_lock(current->mm);
1690 	/*
1691 	 * A memory region could potentially cover multiple VMAs, and any holes
1692 	 * between them, so iterate over all of them.
1693 	 *
1694 	 *     +--------------------------------------------+
1695 	 * +---------------+----------------+   +----------------+
1696 	 * |   : VMA 1     |      VMA 2     |   |    VMA 3  :    |
1697 	 * +---------------+----------------+   +----------------+
1698 	 *     |               memory region                |
1699 	 *     +--------------------------------------------+
1700 	 */
1701 	do {
1702 		struct vm_area_struct *vma;
1703 
1704 		vma = find_vma_intersection(current->mm, hva, reg_end);
1705 		if (!vma)
1706 			break;
1707 
1708 		/*
1709 		 * VM_SHARED mappings are not allowed with MTE to avoid races
1710 		 * when updating the PG_mte_tagged page flag, see
1711 		 * sanitise_mte_tags for more details.
1712 		 */
1713 		if (kvm_has_mte(kvm) && vma->vm_flags & VM_SHARED) {
1714 			ret = -EINVAL;
1715 			break;
1716 		}
1717 
1718 		if (vma->vm_flags & VM_PFNMAP) {
1719 			/* IO region dirty page logging not allowed */
1720 			if (new->flags & KVM_MEM_LOG_DIRTY_PAGES) {
1721 				ret = -EINVAL;
1722 				break;
1723 			}
1724 		}
1725 		hva = min(reg_end, vma->vm_end);
1726 	} while (hva < reg_end);
1727 
1728 	mmap_read_unlock(current->mm);
1729 	return ret;
1730 }
1731 
kvm_arch_free_memslot(struct kvm * kvm,struct kvm_memory_slot * slot)1732 void kvm_arch_free_memslot(struct kvm *kvm, struct kvm_memory_slot *slot)
1733 {
1734 }
1735 
kvm_arch_memslots_updated(struct kvm * kvm,u64 gen)1736 void kvm_arch_memslots_updated(struct kvm *kvm, u64 gen)
1737 {
1738 }
1739 
kvm_arch_flush_shadow_all(struct kvm * kvm)1740 void kvm_arch_flush_shadow_all(struct kvm *kvm)
1741 {
1742 	kvm_free_stage2_pgd(&kvm->arch.mmu);
1743 }
1744 
kvm_arch_flush_shadow_memslot(struct kvm * kvm,struct kvm_memory_slot * slot)1745 void kvm_arch_flush_shadow_memslot(struct kvm *kvm,
1746 				   struct kvm_memory_slot *slot)
1747 {
1748 	gpa_t gpa = slot->base_gfn << PAGE_SHIFT;
1749 	phys_addr_t size = slot->npages << PAGE_SHIFT;
1750 
1751 	write_lock(&kvm->mmu_lock);
1752 	unmap_stage2_range(&kvm->arch.mmu, gpa, size);
1753 	write_unlock(&kvm->mmu_lock);
1754 }
1755 
1756 /*
1757  * See note at ARMv7 ARM B1.14.4 (TL;DR: S/W ops are not easily virtualized).
1758  *
1759  * Main problems:
1760  * - S/W ops are local to a CPU (not broadcast)
1761  * - We have line migration behind our back (speculation)
1762  * - System caches don't support S/W at all (damn!)
1763  *
1764  * In the face of the above, the best we can do is to try and convert
1765  * S/W ops to VA ops. Because the guest is not allowed to infer the
1766  * S/W to PA mapping, it can only use S/W to nuke the whole cache,
1767  * which is a rather good thing for us.
1768  *
1769  * Also, it is only used when turning caches on/off ("The expected
1770  * usage of the cache maintenance instructions that operate by set/way
1771  * is associated with the cache maintenance instructions associated
1772  * with the powerdown and powerup of caches, if this is required by
1773  * the implementation.").
1774  *
1775  * We use the following policy:
1776  *
1777  * - If we trap a S/W operation, we enable VM trapping to detect
1778  *   caches being turned on/off, and do a full clean.
1779  *
1780  * - We flush the caches on both caches being turned on and off.
1781  *
1782  * - Once the caches are enabled, we stop trapping VM ops.
1783  */
kvm_set_way_flush(struct kvm_vcpu * vcpu)1784 void kvm_set_way_flush(struct kvm_vcpu *vcpu)
1785 {
1786 	unsigned long hcr = *vcpu_hcr(vcpu);
1787 
1788 	/*
1789 	 * If this is the first time we do a S/W operation
1790 	 * (i.e. HCR_TVM not set) flush the whole memory, and set the
1791 	 * VM trapping.
1792 	 *
1793 	 * Otherwise, rely on the VM trapping to wait for the MMU +
1794 	 * Caches to be turned off. At that point, we'll be able to
1795 	 * clean the caches again.
1796 	 */
1797 	if (!(hcr & HCR_TVM)) {
1798 		trace_kvm_set_way_flush(*vcpu_pc(vcpu),
1799 					vcpu_has_cache_enabled(vcpu));
1800 		stage2_flush_vm(vcpu->kvm);
1801 		*vcpu_hcr(vcpu) = hcr | HCR_TVM;
1802 	}
1803 }
1804 
kvm_toggle_cache(struct kvm_vcpu * vcpu,bool was_enabled)1805 void kvm_toggle_cache(struct kvm_vcpu *vcpu, bool was_enabled)
1806 {
1807 	bool now_enabled = vcpu_has_cache_enabled(vcpu);
1808 
1809 	/*
1810 	 * If switching the MMU+caches on, need to invalidate the caches.
1811 	 * If switching it off, need to clean the caches.
1812 	 * Clean + invalidate does the trick always.
1813 	 */
1814 	if (now_enabled != was_enabled)
1815 		stage2_flush_vm(vcpu->kvm);
1816 
1817 	/* Caches are now on, stop trapping VM ops (until a S/W op) */
1818 	if (now_enabled)
1819 		*vcpu_hcr(vcpu) &= ~HCR_TVM;
1820 
1821 	trace_kvm_toggle_cache(*vcpu_pc(vcpu), was_enabled, now_enabled);
1822 }
1823