mmu.c 106.8 KB
Newer Older
A
Avi Kivity 已提交
1 2 3 4 5 6 7 8 9
/*
 * Kernel-based Virtual Machine driver for Linux
 *
 * This module enables machines with Intel VT-x extensions to run virtual
 * machines without emulation or binary translation.
 *
 * MMU support
 *
 * Copyright (C) 2006 Qumranet, Inc.
N
Nicolas Kaiser 已提交
10
 * Copyright 2010 Red Hat, Inc. and/or its affiliates.
A
Avi Kivity 已提交
11 12 13 14 15 16 17 18 19
 *
 * Authors:
 *   Yaniv Kamay  <yaniv@qumranet.com>
 *   Avi Kivity   <avi@qumranet.com>
 *
 * This work is licensed under the terms of the GNU GPL, version 2.  See
 * the COPYING file in the top-level directory.
 *
 */
A
Avi Kivity 已提交
20

21
#include "irq.h"
22
#include "mmu.h"
23
#include "x86.h"
A
Avi Kivity 已提交
24
#include "kvm_cache_regs.h"
A
Avi Kivity 已提交
25

26
#include <linux/kvm_host.h>
A
Avi Kivity 已提交
27 28 29 30 31
#include <linux/types.h>
#include <linux/string.h>
#include <linux/mm.h>
#include <linux/highmem.h>
#include <linux/module.h>
32
#include <linux/swap.h>
M
Marcelo Tosatti 已提交
33
#include <linux/hugetlb.h>
34
#include <linux/compiler.h>
35
#include <linux/srcu.h>
36
#include <linux/slab.h>
37
#include <linux/uaccess.h>
A
Avi Kivity 已提交
38

A
Avi Kivity 已提交
39 40
#include <asm/page.h>
#include <asm/cmpxchg.h>
41
#include <asm/io.h>
42
#include <asm/vmx.h>
A
Avi Kivity 已提交
43

44 45 46 47 48 49 50
/*
 * When setting this variable to true it enables Two-Dimensional-Paging
 * where the hardware walks 2 page tables:
 * 1. the guest-virtual to guest-physical
 * 2. while doing 1. it walks guest-physical to host-physical
 * If the hardware supports that we don't need to do shadow paging.
 */
51
bool tdp_enabled = false;
52

53 54 55 56
enum {
	AUDIT_PRE_PAGE_FAULT,
	AUDIT_POST_PAGE_FAULT,
	AUDIT_PRE_PTE_WRITE,
57 58 59
	AUDIT_POST_PTE_WRITE,
	AUDIT_PRE_SYNC,
	AUDIT_POST_SYNC
60
};
61

62
#undef MMU_DEBUG
63 64 65 66 67 68 69 70 71 72 73 74 75

#ifdef MMU_DEBUG

#define pgprintk(x...) do { if (dbg) printk(x); } while (0)
#define rmap_printk(x...) do { if (dbg) printk(x); } while (0)

#else

#define pgprintk(x...) do { } while (0)
#define rmap_printk(x...) do { } while (0)

#endif

76
#ifdef MMU_DEBUG
77
static bool dbg = 0;
78
module_param(dbg, bool, 0644);
79
#endif
A
Avi Kivity 已提交
80

81 82 83
#ifndef MMU_DEBUG
#define ASSERT(x) do { } while (0)
#else
A
Avi Kivity 已提交
84 85 86 87 88
#define ASSERT(x)							\
	if (!(x)) {							\
		printk(KERN_WARNING "assertion failed %s:%d: %s\n",	\
		       __FILE__, __LINE__, #x);				\
	}
89
#endif
A
Avi Kivity 已提交
90

91 92
#define PTE_PREFETCH_NUM		8

93
#define PT_FIRST_AVAIL_BITS_SHIFT 10
A
Avi Kivity 已提交
94 95 96 97 98
#define PT64_SECOND_AVAIL_BITS_SHIFT 52

#define PT64_LEVEL_BITS 9

#define PT64_LEVEL_SHIFT(level) \
M
Mike Day 已提交
99
		(PAGE_SHIFT + (level - 1) * PT64_LEVEL_BITS)
A
Avi Kivity 已提交
100 101 102 103 104 105 106 107

#define PT64_INDEX(address, level)\
	(((address) >> PT64_LEVEL_SHIFT(level)) & ((1 << PT64_LEVEL_BITS) - 1))


#define PT32_LEVEL_BITS 10

#define PT32_LEVEL_SHIFT(level) \
M
Mike Day 已提交
108
		(PAGE_SHIFT + (level - 1) * PT32_LEVEL_BITS)
A
Avi Kivity 已提交
109

110 111 112
#define PT32_LVL_OFFSET_MASK(level) \
	(PT32_BASE_ADDR_MASK & ((1ULL << (PAGE_SHIFT + (((level) - 1) \
						* PT32_LEVEL_BITS))) - 1))
A
Avi Kivity 已提交
113 114 115 116 117

#define PT32_INDEX(address, level)\
	(((address) >> PT32_LEVEL_SHIFT(level)) & ((1 << PT32_LEVEL_BITS) - 1))


118
#define PT64_BASE_ADDR_MASK (((1ULL << 52) - 1) & ~(u64)(PAGE_SIZE-1))
A
Avi Kivity 已提交
119 120
#define PT64_DIR_BASE_ADDR_MASK \
	(PT64_BASE_ADDR_MASK & ~((1ULL << (PAGE_SHIFT + PT64_LEVEL_BITS)) - 1))
121 122 123 124 125 126
#define PT64_LVL_ADDR_MASK(level) \
	(PT64_BASE_ADDR_MASK & ~((1ULL << (PAGE_SHIFT + (((level) - 1) \
						* PT64_LEVEL_BITS))) - 1))
#define PT64_LVL_OFFSET_MASK(level) \
	(PT64_BASE_ADDR_MASK & ((1ULL << (PAGE_SHIFT + (((level) - 1) \
						* PT64_LEVEL_BITS))) - 1))
A
Avi Kivity 已提交
127 128 129 130

#define PT32_BASE_ADDR_MASK PAGE_MASK
#define PT32_DIR_BASE_ADDR_MASK \
	(PAGE_MASK & ~((1ULL << (PAGE_SHIFT + PT32_LEVEL_BITS)) - 1))
131 132 133
#define PT32_LVL_ADDR_MASK(level) \
	(PAGE_MASK & ~((1ULL << (PAGE_SHIFT + (((level) - 1) \
					    * PT32_LEVEL_BITS))) - 1))
A
Avi Kivity 已提交
134

135 136
#define PT64_PERM_MASK (PT_PRESENT_MASK | PT_WRITABLE_MASK | PT_USER_MASK \
			| PT64_NX_MASK)
A
Avi Kivity 已提交
137

138 139 140 141 142
#define ACC_EXEC_MASK    1
#define ACC_WRITE_MASK   PT_WRITABLE_MASK
#define ACC_USER_MASK    PT_USER_MASK
#define ACC_ALL          (ACC_EXEC_MASK | ACC_WRITE_MASK | ACC_USER_MASK)

143 144
#include <trace/events/kvm.h>

145 146 147
#define CREATE_TRACE_POINTS
#include "mmutrace.h"

148 149
#define SPTE_HOST_WRITEABLE	(1ULL << PT_FIRST_AVAIL_BITS_SHIFT)
#define SPTE_MMU_WRITEABLE	(1ULL << (PT_FIRST_AVAIL_BITS_SHIFT + 1))
150

151 152
#define SHADOW_PT_INDEX(addr, level) PT64_INDEX(addr, level)

153 154 155
/* make pte_list_desc fit well in cache line */
#define PTE_LIST_EXT 3

156 157 158
struct pte_list_desc {
	u64 *sptes[PTE_LIST_EXT];
	struct pte_list_desc *more;
159 160
};

161 162 163 164
struct kvm_shadow_walk_iterator {
	u64 addr;
	hpa_t shadow_addr;
	u64 *sptep;
165
	int level;
166 167 168 169 170 171 172 173
	unsigned index;
};

#define for_each_shadow_entry(_vcpu, _addr, _walker)    \
	for (shadow_walk_init(&(_walker), _vcpu, _addr);	\
	     shadow_walk_okay(&(_walker));			\
	     shadow_walk_next(&(_walker)))

174 175 176 177 178 179
#define for_each_shadow_entry_lockless(_vcpu, _addr, _walker, spte)	\
	for (shadow_walk_init(&(_walker), _vcpu, _addr);		\
	     shadow_walk_okay(&(_walker)) &&				\
		({ spte = mmu_spte_get_lockless(_walker.sptep); 1; });	\
	     __shadow_walk_next(&(_walker), spte))

180
static struct kmem_cache *pte_list_desc_cache;
181
static struct kmem_cache *mmu_page_header_cache;
182
static struct percpu_counter kvm_total_used_mmu_pages;
183

S
Sheng Yang 已提交
184 185 186 187 188
static u64 __read_mostly shadow_nx_mask;
static u64 __read_mostly shadow_x_mask;	/* mutual exclusive with nx_mask */
static u64 __read_mostly shadow_user_mask;
static u64 __read_mostly shadow_accessed_mask;
static u64 __read_mostly shadow_dirty_mask;
189 190 191
static u64 __read_mostly shadow_mmio_mask;

static void mmu_spte_set(u64 *sptep, u64 spte);
192
static void mmu_free_roots(struct kvm_vcpu *vcpu);
193 194 195 196 197 198 199 200 201

void kvm_mmu_set_mmio_spte_mask(u64 mmio_mask)
{
	shadow_mmio_mask = mmio_mask;
}
EXPORT_SYMBOL_GPL(kvm_mmu_set_mmio_spte_mask);

static void mark_mmio_spte(u64 *sptep, u64 gfn, unsigned access)
{
202 203
	struct kvm_mmu_page *sp =  page_header(__pa(sptep));

204 205
	access &= ACC_WRITE_MASK | ACC_USER_MASK;

206
	sp->mmio_cached = true;
X
Xiao Guangrong 已提交
207
	trace_mark_mmio_spte(sptep, gfn, access);
208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234
	mmu_spte_set(sptep, shadow_mmio_mask | access | gfn << PAGE_SHIFT);
}

static bool is_mmio_spte(u64 spte)
{
	return (spte & shadow_mmio_mask) == shadow_mmio_mask;
}

static gfn_t get_mmio_spte_gfn(u64 spte)
{
	return (spte & ~shadow_mmio_mask) >> PAGE_SHIFT;
}

static unsigned get_mmio_spte_access(u64 spte)
{
	return (spte & ~shadow_mmio_mask) & ~PAGE_MASK;
}

static bool set_mmio_spte(u64 *sptep, gfn_t gfn, pfn_t pfn, unsigned access)
{
	if (unlikely(is_noslot_pfn(pfn))) {
		mark_mmio_spte(sptep, gfn, access);
		return true;
	}

	return false;
}
235

236 237 238 239 240
static inline u64 rsvd_bits(int s, int e)
{
	return ((1ULL << (e - s + 1)) - 1) << s;
}

S
Sheng Yang 已提交
241
void kvm_mmu_set_mask_ptes(u64 user_mask, u64 accessed_mask,
242
		u64 dirty_mask, u64 nx_mask, u64 x_mask)
S
Sheng Yang 已提交
243 244 245 246 247 248 249 250 251
{
	shadow_user_mask = user_mask;
	shadow_accessed_mask = accessed_mask;
	shadow_dirty_mask = dirty_mask;
	shadow_nx_mask = nx_mask;
	shadow_x_mask = x_mask;
}
EXPORT_SYMBOL_GPL(kvm_mmu_set_mask_ptes);

A
Avi Kivity 已提交
252 253 254 255 256
static int is_cpuid_PSE36(void)
{
	return 1;
}

257 258
static int is_nx(struct kvm_vcpu *vcpu)
{
259
	return vcpu->arch.efer & EFER_NX;
260 261
}

262 263
static int is_shadow_present_pte(u64 pte)
{
264
	return pte & PT_PRESENT_MASK && !is_mmio_spte(pte);
265 266
}

M
Marcelo Tosatti 已提交
267 268 269 270 271
static int is_large_pte(u64 pte)
{
	return pte & PT_PAGE_SIZE_MASK;
}

272
static int is_dirty_gpte(unsigned long pte)
273
{
A
Avi Kivity 已提交
274
	return pte & PT_DIRTY_MASK;
275 276
}

277
static int is_rmap_spte(u64 pte)
278
{
279
	return is_shadow_present_pte(pte);
280 281
}

282 283 284 285
static int is_last_spte(u64 pte, int level)
{
	if (level == PT_PAGE_TABLE_LEVEL)
		return 1;
286
	if (is_large_pte(pte))
287 288 289 290
		return 1;
	return 0;
}

291
static pfn_t spte_to_pfn(u64 pte)
292
{
293
	return (pte & PT64_BASE_ADDR_MASK) >> PAGE_SHIFT;
294 295
}

296 297 298 299 300 301 302
static gfn_t pse36_gfn_delta(u32 gpte)
{
	int shift = 32 - PT32_DIR_PSE36_SHIFT - PAGE_SHIFT;

	return (gpte & PT32_DIR_PSE36_MASK) << shift;
}

303
#ifdef CONFIG_X86_64
A
Avi Kivity 已提交
304
static void __set_spte(u64 *sptep, u64 spte)
305
{
306
	*sptep = spte;
307 308
}

309
static void __update_clear_spte_fast(u64 *sptep, u64 spte)
310
{
311 312 313 314 315 316 317
	*sptep = spte;
}

static u64 __update_clear_spte_slow(u64 *sptep, u64 spte)
{
	return xchg(sptep, spte);
}
318 319 320 321 322

static u64 __get_spte_lockless(u64 *sptep)
{
	return ACCESS_ONCE(*sptep);
}
323 324 325 326 327 328

static bool __check_direct_spte_mmio_pf(u64 spte)
{
	/* It is valid if the spte is zapped. */
	return spte == 0ull;
}
329
#else
330 331 332 333 334 335 336
union split_spte {
	struct {
		u32 spte_low;
		u32 spte_high;
	};
	u64 spte;
};
337

338 339 340 341 342 343 344 345 346 347 348 349
static void count_spte_clear(u64 *sptep, u64 spte)
{
	struct kvm_mmu_page *sp =  page_header(__pa(sptep));

	if (is_shadow_present_pte(spte))
		return;

	/* Ensure the spte is completely set before we increase the count */
	smp_wmb();
	sp->clear_spte_count++;
}

350 351 352
static void __set_spte(u64 *sptep, u64 spte)
{
	union split_spte *ssptep, sspte;
353

354 355 356 357 358 359 360 361 362 363 364 365 366
	ssptep = (union split_spte *)sptep;
	sspte = (union split_spte)spte;

	ssptep->spte_high = sspte.spte_high;

	/*
	 * If we map the spte from nonpresent to present, We should store
	 * the high bits firstly, then set present bit, so cpu can not
	 * fetch this spte while we are setting the spte.
	 */
	smp_wmb();

	ssptep->spte_low = sspte.spte_low;
367 368
}

369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384
static void __update_clear_spte_fast(u64 *sptep, u64 spte)
{
	union split_spte *ssptep, sspte;

	ssptep = (union split_spte *)sptep;
	sspte = (union split_spte)spte;

	ssptep->spte_low = sspte.spte_low;

	/*
	 * If we map the spte from present to nonpresent, we should clear
	 * present bit firstly to avoid vcpu fetch the old high bits.
	 */
	smp_wmb();

	ssptep->spte_high = sspte.spte_high;
385
	count_spte_clear(sptep, spte);
386 387 388 389 390 391 392 393 394 395 396
}

static u64 __update_clear_spte_slow(u64 *sptep, u64 spte)
{
	union split_spte *ssptep, sspte, orig;

	ssptep = (union split_spte *)sptep;
	sspte = (union split_spte)spte;

	/* xchg acts as a barrier before the setting of the high bits */
	orig.spte_low = xchg(&ssptep->spte_low, sspte.spte_low);
397 398
	orig.spte_high = ssptep->spte_high;
	ssptep->spte_high = sspte.spte_high;
399
	count_spte_clear(sptep, spte);
400 401 402

	return orig.spte;
}
403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432

/*
 * The idea using the light way get the spte on x86_32 guest is from
 * gup_get_pte(arch/x86/mm/gup.c).
 * The difference is we can not catch the spte tlb flush if we leave
 * guest mode, so we emulate it by increase clear_spte_count when spte
 * is cleared.
 */
static u64 __get_spte_lockless(u64 *sptep)
{
	struct kvm_mmu_page *sp =  page_header(__pa(sptep));
	union split_spte spte, *orig = (union split_spte *)sptep;
	int count;

retry:
	count = sp->clear_spte_count;
	smp_rmb();

	spte.spte_low = orig->spte_low;
	smp_rmb();

	spte.spte_high = orig->spte_high;
	smp_rmb();

	if (unlikely(spte.spte_low != orig->spte_low ||
	      count != sp->clear_spte_count))
		goto retry;

	return spte.spte;
}
433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449

static bool __check_direct_spte_mmio_pf(u64 spte)
{
	union split_spte sspte = (union split_spte)spte;
	u32 high_mmio_mask = shadow_mmio_mask >> 32;

	/* It is valid if the spte is zapped. */
	if (spte == 0ull)
		return true;

	/* It is valid if the spte is being zapped. */
	if (sspte.spte_low == 0ull &&
	    (sspte.spte_high & high_mmio_mask) == high_mmio_mask)
		return true;

	return false;
}
450 451
#endif

452 453
static bool spte_is_locklessly_modifiable(u64 spte)
{
454 455
	return (spte & (SPTE_HOST_WRITEABLE | SPTE_MMU_WRITEABLE)) ==
		(SPTE_HOST_WRITEABLE | SPTE_MMU_WRITEABLE);
456 457
}

458 459
static bool spte_has_volatile_bits(u64 spte)
{
460 461 462 463 464 465 466 467 468
	/*
	 * Always atomicly update spte if it can be updated
	 * out of mmu-lock, it can ensure dirty bit is not lost,
	 * also, it can help us to get a stable is_writable_pte()
	 * to ensure tlb flush is not missed.
	 */
	if (spte_is_locklessly_modifiable(spte))
		return true;

469 470 471 472 473 474
	if (!shadow_accessed_mask)
		return false;

	if (!is_shadow_present_pte(spte))
		return false;

475 476
	if ((spte & shadow_accessed_mask) &&
	      (!is_writable_pte(spte) || (spte & shadow_dirty_mask)))
477 478 479 480 481
		return false;

	return true;
}

482 483 484 485 486
static bool spte_is_bit_cleared(u64 old_spte, u64 new_spte, u64 bit_mask)
{
	return (old_spte & bit_mask) && !(new_spte & bit_mask);
}

487 488 489 490 491 492 493 494 495 496 497 498 499 500
/* Rules for using mmu_spte_set:
 * Set the sptep from nonpresent to present.
 * Note: the sptep being assigned *must* be either not present
 * or in a state where the hardware will not attempt to update
 * the spte.
 */
static void mmu_spte_set(u64 *sptep, u64 new_spte)
{
	WARN_ON(is_shadow_present_pte(*sptep));
	__set_spte(sptep, new_spte);
}

/* Rules for using mmu_spte_update:
 * Update the state bits, it means the mapped pfn is not changged.
501 502 503 504 505 506
 *
 * Whenever we overwrite a writable spte with a read-only one we
 * should flush remote TLBs. Otherwise rmap_write_protect
 * will find a read-only spte, even though the writable spte
 * might be cached on a CPU's TLB, the return value indicates this
 * case.
507
 */
508
static bool mmu_spte_update(u64 *sptep, u64 new_spte)
509
{
510
	u64 old_spte = *sptep;
511
	bool ret = false;
512 513

	WARN_ON(!is_rmap_spte(new_spte));
514

515 516 517 518
	if (!is_shadow_present_pte(old_spte)) {
		mmu_spte_set(sptep, new_spte);
		return ret;
	}
519

520
	if (!spte_has_volatile_bits(old_spte))
521
		__update_clear_spte_fast(sptep, new_spte);
522
	else
523
		old_spte = __update_clear_spte_slow(sptep, new_spte);
524

525 526 527 528 529
	/*
	 * For the spte updated out of mmu-lock is safe, since
	 * we always atomicly update it, see the comments in
	 * spte_has_volatile_bits().
	 */
530 531 532
	if (is_writable_pte(old_spte) && !is_writable_pte(new_spte))
		ret = true;

533
	if (!shadow_accessed_mask)
534
		return ret;
535 536 537 538 539

	if (spte_is_bit_cleared(old_spte, new_spte, shadow_accessed_mask))
		kvm_set_pfn_accessed(spte_to_pfn(old_spte));
	if (spte_is_bit_cleared(old_spte, new_spte, shadow_dirty_mask))
		kvm_set_pfn_dirty(spte_to_pfn(old_spte));
540 541

	return ret;
542 543
}

544 545 546 547 548 549 550 551 552 553 554
/*
 * Rules for using mmu_spte_clear_track_bits:
 * It sets the sptep from present to nonpresent, and track the
 * state bits, it is used to clear the last level sptep.
 */
static int mmu_spte_clear_track_bits(u64 *sptep)
{
	pfn_t pfn;
	u64 old_spte = *sptep;

	if (!spte_has_volatile_bits(old_spte))
555
		__update_clear_spte_fast(sptep, 0ull);
556
	else
557
		old_spte = __update_clear_spte_slow(sptep, 0ull);
558 559 560 561 562

	if (!is_rmap_spte(old_spte))
		return 0;

	pfn = spte_to_pfn(old_spte);
563 564 565 566 567 568 569 570

	/*
	 * KVM does not hold the refcount of the page used by
	 * kvm mmu, before reclaiming the page, we should
	 * unmap it from mmu first.
	 */
	WARN_ON(!kvm_is_mmio_pfn(pfn) && !page_count(pfn_to_page(pfn)));

571 572 573 574 575 576 577 578 579 580 581 582 583 584
	if (!shadow_accessed_mask || old_spte & shadow_accessed_mask)
		kvm_set_pfn_accessed(pfn);
	if (!shadow_dirty_mask || (old_spte & shadow_dirty_mask))
		kvm_set_pfn_dirty(pfn);
	return 1;
}

/*
 * Rules for using mmu_spte_clear_no_track:
 * Directly clear spte without caring the state bits of sptep,
 * it is used to set the upper level spte.
 */
static void mmu_spte_clear_no_track(u64 *sptep)
{
585
	__update_clear_spte_fast(sptep, 0ull);
586 587
}

588 589 590 591 592 593 594
static u64 mmu_spte_get_lockless(u64 *sptep)
{
	return __get_spte_lockless(sptep);
}

static void walk_shadow_page_lockless_begin(struct kvm_vcpu *vcpu)
{
595 596 597 598 599 600 601 602 603 604 605
	/*
	 * Prevent page table teardown by making any free-er wait during
	 * kvm_flush_remote_tlbs() IPI to all active vcpus.
	 */
	local_irq_disable();
	vcpu->mode = READING_SHADOW_PAGE_TABLES;
	/*
	 * Make sure a following spte read is not reordered ahead of the write
	 * to vcpu->mode.
	 */
	smp_mb();
606 607 608 609
}

static void walk_shadow_page_lockless_end(struct kvm_vcpu *vcpu)
{
610 611 612 613 614 615 616 617
	/*
	 * Make sure the write to vcpu->mode is not reordered in front of
	 * reads to sptes.  If it does, kvm_commit_zap_page() can see us
	 * OUTSIDE_GUEST_MODE and proceed to free the shadow page table.
	 */
	smp_mb();
	vcpu->mode = OUTSIDE_GUEST_MODE;
	local_irq_enable();
618 619
}

620
static int mmu_topup_memory_cache(struct kvm_mmu_memory_cache *cache,
621
				  struct kmem_cache *base_cache, int min)
622 623 624 625
{
	void *obj;

	if (cache->nobjs >= min)
626
		return 0;
627
	while (cache->nobjs < ARRAY_SIZE(cache->objects)) {
628
		obj = kmem_cache_zalloc(base_cache, GFP_KERNEL);
629
		if (!obj)
630
			return -ENOMEM;
631 632
		cache->objects[cache->nobjs++] = obj;
	}
633
	return 0;
634 635
}

636 637 638 639 640
static int mmu_memory_cache_free_objects(struct kvm_mmu_memory_cache *cache)
{
	return cache->nobjs;
}

641 642
static void mmu_free_memory_cache(struct kvm_mmu_memory_cache *mc,
				  struct kmem_cache *cache)
643 644
{
	while (mc->nobjs)
645
		kmem_cache_free(cache, mc->objects[--mc->nobjs]);
646 647
}

A
Avi Kivity 已提交
648
static int mmu_topup_memory_cache_page(struct kvm_mmu_memory_cache *cache,
649
				       int min)
A
Avi Kivity 已提交
650
{
651
	void *page;
A
Avi Kivity 已提交
652 653 654 655

	if (cache->nobjs >= min)
		return 0;
	while (cache->nobjs < ARRAY_SIZE(cache->objects)) {
656
		page = (void *)__get_free_page(GFP_KERNEL);
A
Avi Kivity 已提交
657 658
		if (!page)
			return -ENOMEM;
659
		cache->objects[cache->nobjs++] = page;
A
Avi Kivity 已提交
660 661 662 663 664 665 666
	}
	return 0;
}

static void mmu_free_memory_cache_page(struct kvm_mmu_memory_cache *mc)
{
	while (mc->nobjs)
667
		free_page((unsigned long)mc->objects[--mc->nobjs]);
A
Avi Kivity 已提交
668 669
}

670
static int mmu_topup_memory_caches(struct kvm_vcpu *vcpu)
671
{
672 673
	int r;

674
	r = mmu_topup_memory_cache(&vcpu->arch.mmu_pte_list_desc_cache,
675
				   pte_list_desc_cache, 8 + PTE_PREFETCH_NUM);
676 677
	if (r)
		goto out;
678
	r = mmu_topup_memory_cache_page(&vcpu->arch.mmu_page_cache, 8);
679 680
	if (r)
		goto out;
681
	r = mmu_topup_memory_cache(&vcpu->arch.mmu_page_header_cache,
682
				   mmu_page_header_cache, 4);
683 684
out:
	return r;
685 686 687 688
}

static void mmu_free_memory_caches(struct kvm_vcpu *vcpu)
{
689 690
	mmu_free_memory_cache(&vcpu->arch.mmu_pte_list_desc_cache,
				pte_list_desc_cache);
691
	mmu_free_memory_cache_page(&vcpu->arch.mmu_page_cache);
692 693
	mmu_free_memory_cache(&vcpu->arch.mmu_page_header_cache,
				mmu_page_header_cache);
694 695
}

696
static void *mmu_memory_cache_alloc(struct kvm_mmu_memory_cache *mc)
697 698 699 700 701 702 703 704
{
	void *p;

	BUG_ON(!mc->nobjs);
	p = mc->objects[--mc->nobjs];
	return p;
}

705
static struct pte_list_desc *mmu_alloc_pte_list_desc(struct kvm_vcpu *vcpu)
706
{
707
	return mmu_memory_cache_alloc(&vcpu->arch.mmu_pte_list_desc_cache);
708 709
}

710
static void mmu_free_pte_list_desc(struct pte_list_desc *pte_list_desc)
711
{
712
	kmem_cache_free(pte_list_desc_cache, pte_list_desc);
713 714
}

715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730
static gfn_t kvm_mmu_page_get_gfn(struct kvm_mmu_page *sp, int index)
{
	if (!sp->role.direct)
		return sp->gfns[index];

	return sp->gfn + (index << ((sp->role.level - 1) * PT64_LEVEL_BITS));
}

static void kvm_mmu_page_set_gfn(struct kvm_mmu_page *sp, int index, gfn_t gfn)
{
	if (sp->role.direct)
		BUG_ON(gfn != kvm_mmu_page_get_gfn(sp, index));
	else
		sp->gfns[index] = gfn;
}

M
Marcelo Tosatti 已提交
731
/*
732 733
 * Return the pointer to the large page information for a given gfn,
 * handling slots that are not large page aligned.
M
Marcelo Tosatti 已提交
734
 */
735 736 737
static struct kvm_lpage_info *lpage_info_slot(gfn_t gfn,
					      struct kvm_memory_slot *slot,
					      int level)
M
Marcelo Tosatti 已提交
738 739 740
{
	unsigned long idx;

741
	idx = gfn_to_index(gfn, slot->base_gfn, level);
742
	return &slot->arch.lpage_info[level - 2][idx];
M
Marcelo Tosatti 已提交
743 744 745 746
}

static void account_shadowed(struct kvm *kvm, gfn_t gfn)
{
747
	struct kvm_memory_slot *slot;
748
	struct kvm_lpage_info *linfo;
749
	int i;
M
Marcelo Tosatti 已提交
750

A
Avi Kivity 已提交
751
	slot = gfn_to_memslot(kvm, gfn);
752 753
	for (i = PT_DIRECTORY_LEVEL;
	     i < PT_PAGE_TABLE_LEVEL + KVM_NR_PAGE_SIZES; ++i) {
754 755
		linfo = lpage_info_slot(gfn, slot, i);
		linfo->write_count += 1;
756
	}
757
	kvm->arch.indirect_shadow_pages++;
M
Marcelo Tosatti 已提交
758 759 760 761
}

static void unaccount_shadowed(struct kvm *kvm, gfn_t gfn)
{
762
	struct kvm_memory_slot *slot;
763
	struct kvm_lpage_info *linfo;
764
	int i;
M
Marcelo Tosatti 已提交
765

A
Avi Kivity 已提交
766
	slot = gfn_to_memslot(kvm, gfn);
767 768
	for (i = PT_DIRECTORY_LEVEL;
	     i < PT_PAGE_TABLE_LEVEL + KVM_NR_PAGE_SIZES; ++i) {
769 770 771
		linfo = lpage_info_slot(gfn, slot, i);
		linfo->write_count -= 1;
		WARN_ON(linfo->write_count < 0);
772
	}
773
	kvm->arch.indirect_shadow_pages--;
M
Marcelo Tosatti 已提交
774 775
}

776 777 778
static int has_wrprotected_page(struct kvm *kvm,
				gfn_t gfn,
				int level)
M
Marcelo Tosatti 已提交
779
{
780
	struct kvm_memory_slot *slot;
781
	struct kvm_lpage_info *linfo;
M
Marcelo Tosatti 已提交
782

A
Avi Kivity 已提交
783
	slot = gfn_to_memslot(kvm, gfn);
M
Marcelo Tosatti 已提交
784
	if (slot) {
785 786
		linfo = lpage_info_slot(gfn, slot, level);
		return linfo->write_count;
M
Marcelo Tosatti 已提交
787 788 789 790 791
	}

	return 1;
}

792
static int host_mapping_level(struct kvm *kvm, gfn_t gfn)
M
Marcelo Tosatti 已提交
793
{
J
Joerg Roedel 已提交
794
	unsigned long page_size;
795
	int i, ret = 0;
M
Marcelo Tosatti 已提交
796

J
Joerg Roedel 已提交
797
	page_size = kvm_host_page_size(kvm, gfn);
M
Marcelo Tosatti 已提交
798

799 800 801 802 803 804 805 806
	for (i = PT_PAGE_TABLE_LEVEL;
	     i < (PT_PAGE_TABLE_LEVEL + KVM_NR_PAGE_SIZES); ++i) {
		if (page_size >= KVM_HPAGE_SIZE(i))
			ret = i;
		else
			break;
	}

807
	return ret;
M
Marcelo Tosatti 已提交
808 809
}

810 811 812
static struct kvm_memory_slot *
gfn_to_memslot_dirty_bitmap(struct kvm_vcpu *vcpu, gfn_t gfn,
			    bool no_dirty_log)
M
Marcelo Tosatti 已提交
813 814
{
	struct kvm_memory_slot *slot;
815 816 817 818 819 820 821 822 823 824 825

	slot = gfn_to_memslot(vcpu->kvm, gfn);
	if (!slot || slot->flags & KVM_MEMSLOT_INVALID ||
	      (no_dirty_log && slot->dirty_bitmap))
		slot = NULL;

	return slot;
}

static bool mapping_level_dirty_bitmap(struct kvm_vcpu *vcpu, gfn_t large_gfn)
{
826
	return !gfn_to_memslot_dirty_bitmap(vcpu, large_gfn, true);
827 828 829 830 831
}

static int mapping_level(struct kvm_vcpu *vcpu, gfn_t large_gfn)
{
	int host_level, level, max_level;
M
Marcelo Tosatti 已提交
832

833 834 835 836 837
	host_level = host_mapping_level(vcpu->kvm, large_gfn);

	if (host_level == PT_PAGE_TABLE_LEVEL)
		return host_level;

X
Xiao Guangrong 已提交
838
	max_level = min(kvm_x86_ops->get_lpage_level(), host_level);
839 840

	for (level = PT_DIRECTORY_LEVEL; level <= max_level; ++level)
841 842 843 844
		if (has_wrprotected_page(vcpu->kvm, large_gfn, level))
			break;

	return level - 1;
M
Marcelo Tosatti 已提交
845 846
}

847
/*
848
 * Pte mapping structures:
849
 *
850
 * If pte_list bit zero is zero, then pte_list point to the spte.
851
 *
852 853
 * If pte_list bit zero is one, (then pte_list & ~1) points to a struct
 * pte_list_desc containing more mappings.
854
 *
855
 * Returns the number of pte entries before the spte was added or zero if
856 857
 * the spte was not added.
 *
858
 */
859 860
static int pte_list_add(struct kvm_vcpu *vcpu, u64 *spte,
			unsigned long *pte_list)
861
{
862
	struct pte_list_desc *desc;
863
	int i, count = 0;
864

865 866 867 868 869 870 871
	if (!*pte_list) {
		rmap_printk("pte_list_add: %p %llx 0->1\n", spte, *spte);
		*pte_list = (unsigned long)spte;
	} else if (!(*pte_list & 1)) {
		rmap_printk("pte_list_add: %p %llx 1->many\n", spte, *spte);
		desc = mmu_alloc_pte_list_desc(vcpu);
		desc->sptes[0] = (u64 *)*pte_list;
A
Avi Kivity 已提交
872
		desc->sptes[1] = spte;
873
		*pte_list = (unsigned long)desc | 1;
874
		++count;
875
	} else {
876 877 878
		rmap_printk("pte_list_add: %p %llx many->many\n", spte, *spte);
		desc = (struct pte_list_desc *)(*pte_list & ~1ul);
		while (desc->sptes[PTE_LIST_EXT-1] && desc->more) {
879
			desc = desc->more;
880
			count += PTE_LIST_EXT;
881
		}
882 883
		if (desc->sptes[PTE_LIST_EXT-1]) {
			desc->more = mmu_alloc_pte_list_desc(vcpu);
884 885
			desc = desc->more;
		}
A
Avi Kivity 已提交
886
		for (i = 0; desc->sptes[i]; ++i)
887
			++count;
A
Avi Kivity 已提交
888
		desc->sptes[i] = spte;
889
	}
890
	return count;
891 892
}

893 894 895
static void
pte_list_desc_remove_entry(unsigned long *pte_list, struct pte_list_desc *desc,
			   int i, struct pte_list_desc *prev_desc)
896 897 898
{
	int j;

899
	for (j = PTE_LIST_EXT - 1; !desc->sptes[j] && j > i; --j)
900
		;
A
Avi Kivity 已提交
901 902
	desc->sptes[i] = desc->sptes[j];
	desc->sptes[j] = NULL;
903 904 905
	if (j != 0)
		return;
	if (!prev_desc && !desc->more)
906
		*pte_list = (unsigned long)desc->sptes[0];
907 908 909 910
	else
		if (prev_desc)
			prev_desc->more = desc->more;
		else
911 912
			*pte_list = (unsigned long)desc->more | 1;
	mmu_free_pte_list_desc(desc);
913 914
}

915
static void pte_list_remove(u64 *spte, unsigned long *pte_list)
916
{
917 918
	struct pte_list_desc *desc;
	struct pte_list_desc *prev_desc;
919 920
	int i;

921 922
	if (!*pte_list) {
		printk(KERN_ERR "pte_list_remove: %p 0->BUG\n", spte);
923
		BUG();
924 925 926 927
	} else if (!(*pte_list & 1)) {
		rmap_printk("pte_list_remove:  %p 1->0\n", spte);
		if ((u64 *)*pte_list != spte) {
			printk(KERN_ERR "pte_list_remove:  %p 1->BUG\n", spte);
928 929
			BUG();
		}
930
		*pte_list = 0;
931
	} else {
932 933
		rmap_printk("pte_list_remove:  %p many->many\n", spte);
		desc = (struct pte_list_desc *)(*pte_list & ~1ul);
934 935
		prev_desc = NULL;
		while (desc) {
936
			for (i = 0; i < PTE_LIST_EXT && desc->sptes[i]; ++i)
A
Avi Kivity 已提交
937
				if (desc->sptes[i] == spte) {
938
					pte_list_desc_remove_entry(pte_list,
939
							       desc, i,
940 941 942 943 944 945
							       prev_desc);
					return;
				}
			prev_desc = desc;
			desc = desc->more;
		}
946
		pr_err("pte_list_remove: %p many->many\n", spte);
947 948 949 950
		BUG();
	}
}

951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970
typedef void (*pte_list_walk_fn) (u64 *spte);
static void pte_list_walk(unsigned long *pte_list, pte_list_walk_fn fn)
{
	struct pte_list_desc *desc;
	int i;

	if (!*pte_list)
		return;

	if (!(*pte_list & 1))
		return fn((u64 *)*pte_list);

	desc = (struct pte_list_desc *)(*pte_list & ~1ul);
	while (desc) {
		for (i = 0; i < PTE_LIST_EXT && desc->sptes[i]; ++i)
			fn(desc->sptes[i]);
		desc = desc->more;
	}
}

971
static unsigned long *__gfn_to_rmap(gfn_t gfn, int level,
972
				    struct kvm_memory_slot *slot)
973
{
974
	unsigned long idx;
975

976
	idx = gfn_to_index(gfn, slot->base_gfn, level);
977
	return &slot->arch.rmap[level - PT_PAGE_TABLE_LEVEL][idx];
978 979
}

980 981 982 983 984 985 986 987
/*
 * Take gfn and return the reverse mapping to it.
 */
static unsigned long *gfn_to_rmap(struct kvm *kvm, gfn_t gfn, int level)
{
	struct kvm_memory_slot *slot;

	slot = gfn_to_memslot(kvm, gfn);
988
	return __gfn_to_rmap(gfn, level, slot);
989 990
}

991 992 993 994 995 996 997 998
static bool rmap_can_add(struct kvm_vcpu *vcpu)
{
	struct kvm_mmu_memory_cache *cache;

	cache = &vcpu->arch.mmu_pte_list_desc_cache;
	return mmu_memory_cache_free_objects(cache);
}

999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021
static int rmap_add(struct kvm_vcpu *vcpu, u64 *spte, gfn_t gfn)
{
	struct kvm_mmu_page *sp;
	unsigned long *rmapp;

	sp = page_header(__pa(spte));
	kvm_mmu_page_set_gfn(sp, spte - sp->spt, gfn);
	rmapp = gfn_to_rmap(vcpu->kvm, gfn, sp->role.level);
	return pte_list_add(vcpu, spte, rmapp);
}

static void rmap_remove(struct kvm *kvm, u64 *spte)
{
	struct kvm_mmu_page *sp;
	gfn_t gfn;
	unsigned long *rmapp;

	sp = page_header(__pa(spte));
	gfn = kvm_mmu_page_get_gfn(sp, spte - sp->spt);
	rmapp = gfn_to_rmap(kvm, gfn, sp->role.level);
	pte_list_remove(spte, rmapp);
}

1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 1081 1082
/*
 * Used by the following functions to iterate through the sptes linked by a
 * rmap.  All fields are private and not assumed to be used outside.
 */
struct rmap_iterator {
	/* private fields */
	struct pte_list_desc *desc;	/* holds the sptep if not NULL */
	int pos;			/* index of the sptep */
};

/*
 * Iteration must be started by this function.  This should also be used after
 * removing/dropping sptes from the rmap link because in such cases the
 * information in the itererator may not be valid.
 *
 * Returns sptep if found, NULL otherwise.
 */
static u64 *rmap_get_first(unsigned long rmap, struct rmap_iterator *iter)
{
	if (!rmap)
		return NULL;

	if (!(rmap & 1)) {
		iter->desc = NULL;
		return (u64 *)rmap;
	}

	iter->desc = (struct pte_list_desc *)(rmap & ~1ul);
	iter->pos = 0;
	return iter->desc->sptes[iter->pos];
}

/*
 * Must be used with a valid iterator: e.g. after rmap_get_first().
 *
 * Returns sptep if found, NULL otherwise.
 */
static u64 *rmap_get_next(struct rmap_iterator *iter)
{
	if (iter->desc) {
		if (iter->pos < PTE_LIST_EXT - 1) {
			u64 *sptep;

			++iter->pos;
			sptep = iter->desc->sptes[iter->pos];
			if (sptep)
				return sptep;
		}

		iter->desc = iter->desc->more;

		if (iter->desc) {
			iter->pos = 0;
			/* desc->sptes[0] cannot be NULL */
			return iter->desc->sptes[iter->pos];
		}
	}

	return NULL;
}

1083
static void drop_spte(struct kvm *kvm, u64 *sptep)
1084
{
1085
	if (mmu_spte_clear_track_bits(sptep))
1086
		rmap_remove(kvm, sptep);
A
Avi Kivity 已提交
1087 1088
}

1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109

static bool __drop_large_spte(struct kvm *kvm, u64 *sptep)
{
	if (is_large_pte(*sptep)) {
		WARN_ON(page_header(__pa(sptep))->role.level ==
			PT_PAGE_TABLE_LEVEL);
		drop_spte(kvm, sptep);
		--kvm->stat.lpages;
		return true;
	}

	return false;
}

static void drop_large_spte(struct kvm_vcpu *vcpu, u64 *sptep)
{
	if (__drop_large_spte(vcpu->kvm, sptep))
		kvm_flush_remote_tlbs(vcpu->kvm);
}

/*
1110
 * Write-protect on the specified @sptep, @pt_protect indicates whether
1111 1112
 * spte writ-protection is caused by protecting shadow page table.
 * @flush indicates whether tlb need be flushed.
1113 1114 1115 1116 1117 1118 1119
 *
 * Note: write protection is difference between drity logging and spte
 * protection:
 * - for dirty logging, the spte can be set to writable at anytime if
 *   its dirty bitmap is properly set.
 * - for spte protection, the spte can be writable only after unsync-ing
 *   shadow page.
1120
 *
1121
 * Return true if the spte is dropped.
1122
 */
1123 1124
static bool
spte_write_protect(struct kvm *kvm, u64 *sptep, bool *flush, bool pt_protect)
1125 1126 1127
{
	u64 spte = *sptep;

1128 1129
	if (!is_writable_pte(spte) &&
	      !(pt_protect && spte_is_locklessly_modifiable(spte)))
1130 1131 1132 1133
		return false;

	rmap_printk("rmap_write_protect: spte %p %llx\n", sptep, *sptep);

1134 1135 1136 1137 1138
	if (__drop_large_spte(kvm, sptep)) {
		*flush |= true;
		return true;
	}

1139 1140
	if (pt_protect)
		spte &= ~SPTE_MMU_WRITEABLE;
1141
	spte = spte & ~PT_WRITABLE_MASK;
1142

1143 1144
	*flush |= mmu_spte_update(sptep, spte);
	return false;
1145 1146
}

1147
static bool __rmap_write_protect(struct kvm *kvm, unsigned long *rmapp,
1148
				 bool pt_protect)
1149
{
1150 1151
	u64 *sptep;
	struct rmap_iterator iter;
1152
	bool flush = false;
1153

1154 1155
	for (sptep = rmap_get_first(*rmapp, &iter); sptep;) {
		BUG_ON(!(*sptep & PT_PRESENT_MASK));
1156 1157 1158 1159
		if (spte_write_protect(kvm, sptep, &flush, pt_protect)) {
			sptep = rmap_get_first(*rmapp, &iter);
			continue;
		}
1160

1161
		sptep = rmap_get_next(&iter);
1162
	}
1163

1164
	return flush;
1165 1166
}

1167 1168 1169 1170 1171 1172 1173 1174 1175 1176 1177 1178 1179
/**
 * kvm_mmu_write_protect_pt_masked - write protect selected PT level pages
 * @kvm: kvm instance
 * @slot: slot to protect
 * @gfn_offset: start of the BITS_PER_LONG pages we care about
 * @mask: indicates which pages we should protect
 *
 * Used when we do not need to care about huge page mappings: e.g. during dirty
 * logging we do not have any such mappings.
 */
void kvm_mmu_write_protect_pt_masked(struct kvm *kvm,
				     struct kvm_memory_slot *slot,
				     gfn_t gfn_offset, unsigned long mask)
1180 1181 1182
{
	unsigned long *rmapp;

1183
	while (mask) {
1184 1185
		rmapp = __gfn_to_rmap(slot->base_gfn + gfn_offset + __ffs(mask),
				      PT_PAGE_TABLE_LEVEL, slot);
1186
		__rmap_write_protect(kvm, rmapp, false);
M
Marcelo Tosatti 已提交
1187

1188 1189 1190
		/* clear the first set bit */
		mask &= mask - 1;
	}
1191 1192
}

1193
static bool rmap_write_protect(struct kvm *kvm, u64 gfn)
1194 1195
{
	struct kvm_memory_slot *slot;
1196 1197
	unsigned long *rmapp;
	int i;
1198
	bool write_protected = false;
1199 1200

	slot = gfn_to_memslot(kvm, gfn);
1201 1202 1203 1204

	for (i = PT_PAGE_TABLE_LEVEL;
	     i < PT_PAGE_TABLE_LEVEL + KVM_NR_PAGE_SIZES; ++i) {
		rmapp = __gfn_to_rmap(gfn, i, slot);
1205
		write_protected |= __rmap_write_protect(kvm, rmapp, true);
1206 1207 1208
	}

	return write_protected;
1209 1210
}

F
Frederik Deweerdt 已提交
1211
static int kvm_unmap_rmapp(struct kvm *kvm, unsigned long *rmapp,
1212
			   struct kvm_memory_slot *slot, unsigned long data)
1213
{
1214 1215
	u64 *sptep;
	struct rmap_iterator iter;
1216 1217
	int need_tlb_flush = 0;

1218 1219 1220 1221 1222
	while ((sptep = rmap_get_first(*rmapp, &iter))) {
		BUG_ON(!(*sptep & PT_PRESENT_MASK));
		rmap_printk("kvm_rmap_unmap_hva: spte %p %llx\n", sptep, *sptep);

		drop_spte(kvm, sptep);
1223 1224
		need_tlb_flush = 1;
	}
1225

1226 1227 1228
	return need_tlb_flush;
}

F
Frederik Deweerdt 已提交
1229
static int kvm_set_pte_rmapp(struct kvm *kvm, unsigned long *rmapp,
1230
			     struct kvm_memory_slot *slot, unsigned long data)
1231
{
1232 1233
	u64 *sptep;
	struct rmap_iterator iter;
1234
	int need_flush = 0;
1235
	u64 new_spte;
1236 1237 1238 1239 1240
	pte_t *ptep = (pte_t *)data;
	pfn_t new_pfn;

	WARN_ON(pte_huge(*ptep));
	new_pfn = pte_pfn(*ptep);
1241 1242 1243 1244 1245

	for (sptep = rmap_get_first(*rmapp, &iter); sptep;) {
		BUG_ON(!is_shadow_present_pte(*sptep));
		rmap_printk("kvm_set_pte_rmapp: spte %p %llx\n", sptep, *sptep);

1246
		need_flush = 1;
1247

1248
		if (pte_write(*ptep)) {
1249 1250
			drop_spte(kvm, sptep);
			sptep = rmap_get_first(*rmapp, &iter);
1251
		} else {
1252
			new_spte = *sptep & ~PT64_BASE_ADDR_MASK;
1253 1254 1255 1256
			new_spte |= (u64)new_pfn << PAGE_SHIFT;

			new_spte &= ~PT_WRITABLE_MASK;
			new_spte &= ~SPTE_HOST_WRITEABLE;
1257
			new_spte &= ~shadow_accessed_mask;
1258 1259 1260 1261

			mmu_spte_clear_track_bits(sptep);
			mmu_spte_set(sptep, new_spte);
			sptep = rmap_get_next(&iter);
1262 1263
		}
	}
1264

1265 1266 1267 1268 1269 1270
	if (need_flush)
		kvm_flush_remote_tlbs(kvm);

	return 0;
}

1271 1272 1273 1274 1275 1276
static int kvm_handle_hva_range(struct kvm *kvm,
				unsigned long start,
				unsigned long end,
				unsigned long data,
				int (*handler)(struct kvm *kvm,
					       unsigned long *rmapp,
1277
					       struct kvm_memory_slot *slot,
1278
					       unsigned long data))
1279
{
1280
	int j;
1281
	int ret = 0;
1282
	struct kvm_memslots *slots;
1283
	struct kvm_memory_slot *memslot;
1284

1285
	slots = kvm_memslots(kvm);
1286

1287
	kvm_for_each_memslot(memslot, slots) {
1288
		unsigned long hva_start, hva_end;
1289
		gfn_t gfn_start, gfn_end;
1290

1291 1292 1293 1294 1295 1296 1297
		hva_start = max(start, memslot->userspace_addr);
		hva_end = min(end, memslot->userspace_addr +
					(memslot->npages << PAGE_SHIFT));
		if (hva_start >= hva_end)
			continue;
		/*
		 * {gfn(page) | page intersects with [hva_start, hva_end)} =
1298
		 * {gfn_start, gfn_start+1, ..., gfn_end-1}.
1299
		 */
1300
		gfn_start = hva_to_gfn_memslot(hva_start, memslot);
1301
		gfn_end = hva_to_gfn_memslot(hva_end + PAGE_SIZE - 1, memslot);
1302

1303 1304 1305 1306
		for (j = PT_PAGE_TABLE_LEVEL;
		     j < PT_PAGE_TABLE_LEVEL + KVM_NR_PAGE_SIZES; ++j) {
			unsigned long idx, idx_end;
			unsigned long *rmapp;
1307

1308 1309 1310 1311 1312 1313
			/*
			 * {idx(page_j) | page_j intersects with
			 *  [hva_start, hva_end)} = {idx, idx+1, ..., idx_end}.
			 */
			idx = gfn_to_index(gfn_start, memslot->base_gfn, j);
			idx_end = gfn_to_index(gfn_end - 1, memslot->base_gfn, j);
1314

1315
			rmapp = __gfn_to_rmap(gfn_start, j, memslot);
1316

1317 1318
			for (; idx <= idx_end; ++idx)
				ret |= handler(kvm, rmapp++, memslot, data);
1319 1320 1321
		}
	}

1322
	return ret;
1323 1324
}

1325 1326 1327
static int kvm_handle_hva(struct kvm *kvm, unsigned long hva,
			  unsigned long data,
			  int (*handler)(struct kvm *kvm, unsigned long *rmapp,
1328
					 struct kvm_memory_slot *slot,
1329 1330 1331
					 unsigned long data))
{
	return kvm_handle_hva_range(kvm, hva, hva + 1, data, handler);
1332 1333 1334 1335
}

int kvm_unmap_hva(struct kvm *kvm, unsigned long hva)
{
1336 1337 1338
	return kvm_handle_hva(kvm, hva, 0, kvm_unmap_rmapp);
}

1339 1340 1341 1342 1343
int kvm_unmap_hva_range(struct kvm *kvm, unsigned long start, unsigned long end)
{
	return kvm_handle_hva_range(kvm, start, end, 0, kvm_unmap_rmapp);
}

1344 1345
void kvm_set_spte_hva(struct kvm *kvm, unsigned long hva, pte_t pte)
{
F
Frederik Deweerdt 已提交
1346
	kvm_handle_hva(kvm, hva, (unsigned long)&pte, kvm_set_pte_rmapp);
1347 1348
}

F
Frederik Deweerdt 已提交
1349
static int kvm_age_rmapp(struct kvm *kvm, unsigned long *rmapp,
1350
			 struct kvm_memory_slot *slot, unsigned long data)
1351
{
1352
	u64 *sptep;
1353
	struct rmap_iterator uninitialized_var(iter);
1354 1355
	int young = 0;

1356
	/*
1357 1358
	 * In case of absence of EPT Access and Dirty Bits supports,
	 * emulate the accessed bit for EPT, by checking if this page has
1359 1360 1361 1362 1363
	 * an EPT mapping, and clearing it if it does. On the next access,
	 * a new EPT mapping will be established.
	 * This has some overhead, but not as much as the cost of swapping
	 * out actively used pages or breaking up actively used hugepages.
	 */
1364 1365 1366 1367
	if (!shadow_accessed_mask) {
		young = kvm_unmap_rmapp(kvm, rmapp, slot, data);
		goto out;
	}
1368

1369 1370
	for (sptep = rmap_get_first(*rmapp, &iter); sptep;
	     sptep = rmap_get_next(&iter)) {
1371
		BUG_ON(!is_shadow_present_pte(*sptep));
1372

1373
		if (*sptep & shadow_accessed_mask) {
1374
			young = 1;
1375 1376
			clear_bit((ffs(shadow_accessed_mask) - 1),
				 (unsigned long *)sptep);
1377 1378
		}
	}
1379 1380 1381
out:
	/* @data has hva passed to kvm_age_hva(). */
	trace_kvm_age_page(data, slot, young);
1382 1383 1384
	return young;
}

A
Andrea Arcangeli 已提交
1385
static int kvm_test_age_rmapp(struct kvm *kvm, unsigned long *rmapp,
1386
			      struct kvm_memory_slot *slot, unsigned long data)
A
Andrea Arcangeli 已提交
1387
{
1388 1389
	u64 *sptep;
	struct rmap_iterator iter;
A
Andrea Arcangeli 已提交
1390 1391 1392 1393 1394 1395 1396 1397 1398 1399
	int young = 0;

	/*
	 * If there's no access bit in the secondary pte set by the
	 * hardware it's up to gup-fast/gup to set the access bit in
	 * the primary pte or in the page structure.
	 */
	if (!shadow_accessed_mask)
		goto out;

1400 1401
	for (sptep = rmap_get_first(*rmapp, &iter); sptep;
	     sptep = rmap_get_next(&iter)) {
1402
		BUG_ON(!is_shadow_present_pte(*sptep));
1403

1404
		if (*sptep & shadow_accessed_mask) {
A
Andrea Arcangeli 已提交
1405 1406 1407 1408 1409 1410 1411 1412
			young = 1;
			break;
		}
	}
out:
	return young;
}

1413 1414
#define RMAP_RECYCLE_THRESHOLD 1000

1415
static void rmap_recycle(struct kvm_vcpu *vcpu, u64 *spte, gfn_t gfn)
1416 1417
{
	unsigned long *rmapp;
1418 1419 1420
	struct kvm_mmu_page *sp;

	sp = page_header(__pa(spte));
1421

1422
	rmapp = gfn_to_rmap(vcpu->kvm, gfn, sp->role.level);
1423

1424
	kvm_unmap_rmapp(vcpu->kvm, rmapp, NULL, 0);
1425 1426 1427
	kvm_flush_remote_tlbs(vcpu->kvm);
}

1428 1429
int kvm_age_hva(struct kvm *kvm, unsigned long hva)
{
1430
	return kvm_handle_hva(kvm, hva, hva, kvm_age_rmapp);
1431 1432
}

A
Andrea Arcangeli 已提交
1433 1434 1435 1436 1437
int kvm_test_age_hva(struct kvm *kvm, unsigned long hva)
{
	return kvm_handle_hva(kvm, hva, 0, kvm_test_age_rmapp);
}

1438
#ifdef MMU_DEBUG
1439
static int is_empty_shadow_page(u64 *spt)
A
Avi Kivity 已提交
1440
{
1441 1442 1443
	u64 *pos;
	u64 *end;

1444
	for (pos = spt, end = pos + PAGE_SIZE / sizeof(u64); pos != end; pos++)
1445
		if (is_shadow_present_pte(*pos)) {
1446
			printk(KERN_ERR "%s: %p %llx\n", __func__,
1447
			       pos, *pos);
A
Avi Kivity 已提交
1448
			return 0;
1449
		}
A
Avi Kivity 已提交
1450 1451
	return 1;
}
1452
#endif
A
Avi Kivity 已提交
1453

1454 1455 1456 1457 1458 1459 1460 1461 1462 1463 1464 1465
/*
 * This value is the sum of all of the kvm instances's
 * kvm->arch.n_used_mmu_pages values.  We need a global,
 * aggregate version in order to make the slab shrinker
 * faster
 */
static inline void kvm_mod_used_mmu_pages(struct kvm *kvm, int nr)
{
	kvm->arch.n_used_mmu_pages += nr;
	percpu_counter_add(&kvm_total_used_mmu_pages, nr);
}

1466
static void kvm_mmu_free_page(struct kvm_mmu_page *sp)
1467
{
1468
	ASSERT(is_empty_shadow_page(sp->spt));
1469
	hlist_del(&sp->hash_link);
1470 1471
	list_del(&sp->link);
	free_page((unsigned long)sp->spt);
1472 1473
	if (!sp->role.direct)
		free_page((unsigned long)sp->gfns);
1474
	kmem_cache_free(mmu_page_header_cache, sp);
1475 1476
}

1477 1478
static unsigned kvm_page_table_hashfn(gfn_t gfn)
{
1479
	return gfn & ((1 << KVM_MMU_HASH_SHIFT) - 1);
1480 1481
}

1482
static void mmu_page_add_parent_pte(struct kvm_vcpu *vcpu,
1483
				    struct kvm_mmu_page *sp, u64 *parent_pte)
1484 1485 1486 1487
{
	if (!parent_pte)
		return;

1488
	pte_list_add(vcpu, parent_pte, &sp->parent_ptes);
1489 1490
}

1491
static void mmu_page_remove_parent_pte(struct kvm_mmu_page *sp,
1492 1493
				       u64 *parent_pte)
{
1494
	pte_list_remove(parent_pte, &sp->parent_ptes);
1495 1496
}

1497 1498 1499 1500
static void drop_parent_pte(struct kvm_mmu_page *sp,
			    u64 *parent_pte)
{
	mmu_page_remove_parent_pte(sp, parent_pte);
1501
	mmu_spte_clear_no_track(parent_pte);
1502 1503
}

1504 1505
static struct kvm_mmu_page *kvm_mmu_alloc_page(struct kvm_vcpu *vcpu,
					       u64 *parent_pte, int direct)
M
Marcelo Tosatti 已提交
1506
{
1507
	struct kvm_mmu_page *sp;
1508

1509 1510
	sp = mmu_memory_cache_alloc(&vcpu->arch.mmu_page_header_cache);
	sp->spt = mmu_memory_cache_alloc(&vcpu->arch.mmu_page_cache);
1511
	if (!direct)
1512
		sp->gfns = mmu_memory_cache_alloc(&vcpu->arch.mmu_page_cache);
1513
	set_page_private(virt_to_page(sp->spt), (unsigned long)sp);
1514 1515 1516 1517 1518 1519

	/*
	 * The active_mmu_pages list is the FIFO list, do not move the
	 * page until it is zapped. kvm_zap_obsolete_pages depends on
	 * this feature. See the comments in kvm_zap_obsolete_pages().
	 */
1520 1521 1522 1523 1524
	list_add(&sp->link, &vcpu->kvm->arch.active_mmu_pages);
	sp->parent_ptes = 0;
	mmu_page_add_parent_pte(vcpu, sp, parent_pte);
	kvm_mod_used_mmu_pages(vcpu->kvm, +1);
	return sp;
M
Marcelo Tosatti 已提交
1525 1526
}

1527
static void mark_unsync(u64 *spte);
1528
static void kvm_mmu_mark_parents_unsync(struct kvm_mmu_page *sp)
1529
{
1530
	pte_list_walk(&sp->parent_ptes, mark_unsync);
1531 1532
}

1533
static void mark_unsync(u64 *spte)
1534
{
1535
	struct kvm_mmu_page *sp;
1536
	unsigned int index;
1537

1538
	sp = page_header(__pa(spte));
1539 1540
	index = spte - sp->spt;
	if (__test_and_set_bit(index, sp->unsync_child_bitmap))
1541
		return;
1542
	if (sp->unsync_children++)
1543
		return;
1544
	kvm_mmu_mark_parents_unsync(sp);
1545 1546
}

1547
static int nonpaging_sync_page(struct kvm_vcpu *vcpu,
1548
			       struct kvm_mmu_page *sp)
1549 1550 1551 1552
{
	return 1;
}

M
Marcelo Tosatti 已提交
1553 1554 1555 1556
static void nonpaging_invlpg(struct kvm_vcpu *vcpu, gva_t gva)
{
}

1557 1558
static void nonpaging_update_pte(struct kvm_vcpu *vcpu,
				 struct kvm_mmu_page *sp, u64 *spte,
1559
				 const void *pte)
1560 1561 1562 1563
{
	WARN_ON(1);
}

1564 1565 1566 1567 1568 1569 1570 1571 1572 1573
#define KVM_PAGE_ARRAY_NR 16

struct kvm_mmu_pages {
	struct mmu_page_and_offset {
		struct kvm_mmu_page *sp;
		unsigned int idx;
	} page[KVM_PAGE_ARRAY_NR];
	unsigned int nr;
};

1574 1575
static int mmu_pages_add(struct kvm_mmu_pages *pvec, struct kvm_mmu_page *sp,
			 int idx)
1576
{
1577
	int i;
1578

1579 1580 1581 1582 1583 1584 1585 1586 1587 1588 1589 1590 1591 1592 1593
	if (sp->unsync)
		for (i=0; i < pvec->nr; i++)
			if (pvec->page[i].sp == sp)
				return 0;

	pvec->page[pvec->nr].sp = sp;
	pvec->page[pvec->nr].idx = idx;
	pvec->nr++;
	return (pvec->nr == KVM_PAGE_ARRAY_NR);
}

static int __mmu_unsync_walk(struct kvm_mmu_page *sp,
			   struct kvm_mmu_pages *pvec)
{
	int i, ret, nr_unsync_leaf = 0;
1594

1595
	for_each_set_bit(i, sp->unsync_child_bitmap, 512) {
1596
		struct kvm_mmu_page *child;
1597 1598
		u64 ent = sp->spt[i];

1599 1600 1601 1602 1603 1604 1605 1606 1607 1608 1609 1610 1611 1612 1613 1614 1615 1616 1617 1618 1619 1620 1621 1622 1623 1624 1625 1626 1627
		if (!is_shadow_present_pte(ent) || is_large_pte(ent))
			goto clear_child_bitmap;

		child = page_header(ent & PT64_BASE_ADDR_MASK);

		if (child->unsync_children) {
			if (mmu_pages_add(pvec, child, i))
				return -ENOSPC;

			ret = __mmu_unsync_walk(child, pvec);
			if (!ret)
				goto clear_child_bitmap;
			else if (ret > 0)
				nr_unsync_leaf += ret;
			else
				return ret;
		} else if (child->unsync) {
			nr_unsync_leaf++;
			if (mmu_pages_add(pvec, child, i))
				return -ENOSPC;
		} else
			 goto clear_child_bitmap;

		continue;

clear_child_bitmap:
		__clear_bit(i, sp->unsync_child_bitmap);
		sp->unsync_children--;
		WARN_ON((int)sp->unsync_children < 0);
1628 1629 1630
	}


1631 1632 1633 1634 1635 1636 1637 1638 1639 1640 1641
	return nr_unsync_leaf;
}

static int mmu_unsync_walk(struct kvm_mmu_page *sp,
			   struct kvm_mmu_pages *pvec)
{
	if (!sp->unsync_children)
		return 0;

	mmu_pages_add(pvec, sp, 0);
	return __mmu_unsync_walk(sp, pvec);
1642 1643 1644 1645 1646
}

static void kvm_unlink_unsync_page(struct kvm *kvm, struct kvm_mmu_page *sp)
{
	WARN_ON(!sp->unsync);
1647
	trace_kvm_mmu_sync_page(sp);
1648 1649 1650 1651
	sp->unsync = 0;
	--kvm->stat.mmu_unsync;
}

1652 1653 1654 1655
static int kvm_mmu_prepare_zap_page(struct kvm *kvm, struct kvm_mmu_page *sp,
				    struct list_head *invalid_list);
static void kvm_mmu_commit_zap_page(struct kvm *kvm,
				    struct list_head *invalid_list);
1656

1657 1658 1659 1660 1661 1662 1663 1664
#define for_each_gfn_sp(_kvm, _sp, _gfn)				\
	hlist_for_each_entry(_sp,					\
	  &(_kvm)->arch.mmu_page_hash[kvm_page_table_hashfn(_gfn)], hash_link) \
		if ((_sp)->gfn != (_gfn)) {} else

#define for_each_gfn_indirect_valid_sp(_kvm, _sp, _gfn)			\
	for_each_gfn_sp(_kvm, _sp, _gfn)				\
		if ((_sp)->role.direct || (_sp)->role.invalid) {} else
1665

1666
/* @sp->gfn should be write-protected at the call site */
1667
static int __kvm_sync_page(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp,
1668
			   struct list_head *invalid_list, bool clear_unsync)
1669
{
1670
	if (sp->role.cr4_pae != !!is_pae(vcpu)) {
1671
		kvm_mmu_prepare_zap_page(vcpu->kvm, sp, invalid_list);
1672 1673 1674
		return 1;
	}

1675
	if (clear_unsync)
1676 1677
		kvm_unlink_unsync_page(vcpu->kvm, sp);

1678
	if (vcpu->arch.mmu.sync_page(vcpu, sp)) {
1679
		kvm_mmu_prepare_zap_page(vcpu->kvm, sp, invalid_list);
1680 1681 1682 1683 1684 1685 1686
		return 1;
	}

	kvm_mmu_flush_tlb(vcpu);
	return 0;
}

1687 1688 1689
static int kvm_sync_page_transient(struct kvm_vcpu *vcpu,
				   struct kvm_mmu_page *sp)
{
1690
	LIST_HEAD(invalid_list);
1691 1692
	int ret;

1693
	ret = __kvm_sync_page(vcpu, sp, &invalid_list, false);
1694
	if (ret)
1695 1696
		kvm_mmu_commit_zap_page(vcpu->kvm, &invalid_list);

1697 1698 1699
	return ret;
}

1700 1701 1702 1703 1704 1705 1706
#ifdef CONFIG_KVM_MMU_AUDIT
#include "mmu_audit.c"
#else
static void kvm_mmu_audit(struct kvm_vcpu *vcpu, int point) { }
static void mmu_audit_disable(void) { }
#endif

1707 1708
static int kvm_sync_page(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp,
			 struct list_head *invalid_list)
1709
{
1710
	return __kvm_sync_page(vcpu, sp, invalid_list, true);
1711 1712
}

1713 1714 1715 1716
/* @gfn should be write-protected at the call site */
static void kvm_sync_pages(struct kvm_vcpu *vcpu,  gfn_t gfn)
{
	struct kvm_mmu_page *s;
1717
	LIST_HEAD(invalid_list);
1718 1719
	bool flush = false;

1720
	for_each_gfn_indirect_valid_sp(vcpu->kvm, s, gfn) {
1721
		if (!s->unsync)
1722 1723 1724
			continue;

		WARN_ON(s->role.level != PT_PAGE_TABLE_LEVEL);
1725
		kvm_unlink_unsync_page(vcpu->kvm, s);
1726
		if ((s->role.cr4_pae != !!is_pae(vcpu)) ||
1727
			(vcpu->arch.mmu.sync_page(vcpu, s))) {
1728
			kvm_mmu_prepare_zap_page(vcpu->kvm, s, &invalid_list);
1729 1730 1731 1732 1733
			continue;
		}
		flush = true;
	}

1734
	kvm_mmu_commit_zap_page(vcpu->kvm, &invalid_list);
1735 1736 1737 1738
	if (flush)
		kvm_mmu_flush_tlb(vcpu);
}

1739 1740 1741
struct mmu_page_path {
	struct kvm_mmu_page *parent[PT64_ROOT_LEVEL-1];
	unsigned int idx[PT64_ROOT_LEVEL-1];
1742 1743
};

1744 1745 1746 1747 1748 1749
#define for_each_sp(pvec, sp, parents, i)			\
		for (i = mmu_pages_next(&pvec, &parents, -1),	\
			sp = pvec.page[i].sp;			\
			i < pvec.nr && ({ sp = pvec.page[i].sp; 1;});	\
			i = mmu_pages_next(&pvec, &parents, i))

1750 1751 1752
static int mmu_pages_next(struct kvm_mmu_pages *pvec,
			  struct mmu_page_path *parents,
			  int i)
1753 1754 1755 1756 1757 1758 1759 1760 1761 1762 1763 1764 1765 1766 1767 1768 1769 1770
{
	int n;

	for (n = i+1; n < pvec->nr; n++) {
		struct kvm_mmu_page *sp = pvec->page[n].sp;

		if (sp->role.level == PT_PAGE_TABLE_LEVEL) {
			parents->idx[0] = pvec->page[n].idx;
			return n;
		}

		parents->parent[sp->role.level-2] = sp;
		parents->idx[sp->role.level-1] = pvec->page[n].idx;
	}

	return n;
}

1771
static void mmu_pages_clear_parents(struct mmu_page_path *parents)
1772
{
1773 1774 1775 1776 1777
	struct kvm_mmu_page *sp;
	unsigned int level = 0;

	do {
		unsigned int idx = parents->idx[level];
1778

1779 1780 1781 1782 1783 1784 1785 1786 1787
		sp = parents->parent[level];
		if (!sp)
			return;

		--sp->unsync_children;
		WARN_ON((int)sp->unsync_children < 0);
		__clear_bit(idx, sp->unsync_child_bitmap);
		level++;
	} while (level < PT64_ROOT_LEVEL-1 && !sp->unsync_children);
1788 1789
}

1790 1791 1792
static void kvm_mmu_pages_init(struct kvm_mmu_page *parent,
			       struct mmu_page_path *parents,
			       struct kvm_mmu_pages *pvec)
1793
{
1794 1795 1796
	parents->parent[parent->role.level-1] = NULL;
	pvec->nr = 0;
}
1797

1798 1799 1800 1801 1802 1803 1804
static void mmu_sync_children(struct kvm_vcpu *vcpu,
			      struct kvm_mmu_page *parent)
{
	int i;
	struct kvm_mmu_page *sp;
	struct mmu_page_path parents;
	struct kvm_mmu_pages pages;
1805
	LIST_HEAD(invalid_list);
1806 1807 1808

	kvm_mmu_pages_init(parent, &parents, &pages);
	while (mmu_unsync_walk(parent, &pages)) {
1809
		bool protected = false;
1810 1811 1812 1813 1814 1815 1816

		for_each_sp(pages, sp, parents, i)
			protected |= rmap_write_protect(vcpu->kvm, sp->gfn);

		if (protected)
			kvm_flush_remote_tlbs(vcpu->kvm);

1817
		for_each_sp(pages, sp, parents, i) {
1818
			kvm_sync_page(vcpu, sp, &invalid_list);
1819 1820
			mmu_pages_clear_parents(&parents);
		}
1821
		kvm_mmu_commit_zap_page(vcpu->kvm, &invalid_list);
1822
		cond_resched_lock(&vcpu->kvm->mmu_lock);
1823 1824
		kvm_mmu_pages_init(parent, &parents, &pages);
	}
1825 1826
}

1827 1828 1829 1830 1831 1832 1833 1834
static void init_shadow_page_table(struct kvm_mmu_page *sp)
{
	int i;

	for (i = 0; i < PT64_ENT_PER_PAGE; ++i)
		sp->spt[i] = 0ull;
}

1835 1836 1837 1838 1839 1840 1841 1842 1843 1844 1845 1846
static void __clear_sp_write_flooding_count(struct kvm_mmu_page *sp)
{
	sp->write_flooding_count = 0;
}

static void clear_sp_write_flooding_count(u64 *spte)
{
	struct kvm_mmu_page *sp =  page_header(__pa(spte));

	__clear_sp_write_flooding_count(sp);
}

1847 1848 1849 1850 1851
static bool is_obsolete_sp(struct kvm *kvm, struct kvm_mmu_page *sp)
{
	return unlikely(sp->mmu_valid_gen != kvm->arch.mmu_valid_gen);
}

1852 1853 1854 1855
static struct kvm_mmu_page *kvm_mmu_get_page(struct kvm_vcpu *vcpu,
					     gfn_t gfn,
					     gva_t gaddr,
					     unsigned level,
1856
					     int direct,
1857
					     unsigned access,
1858
					     u64 *parent_pte)
1859 1860 1861
{
	union kvm_mmu_page_role role;
	unsigned quadrant;
1862 1863
	struct kvm_mmu_page *sp;
	bool need_sync = false;
1864

1865
	role = vcpu->arch.mmu.base_role;
1866
	role.level = level;
1867
	role.direct = direct;
1868
	if (role.direct)
1869
		role.cr4_pae = 0;
1870
	role.access = access;
1871 1872
	if (!vcpu->arch.mmu.direct_map
	    && vcpu->arch.mmu.root_level <= PT32_ROOT_LEVEL) {
1873 1874 1875 1876
		quadrant = gaddr >> (PAGE_SHIFT + (PT64_PT_BITS * level));
		quadrant &= (1 << ((PT32_PT_BITS - PT64_PT_BITS) * level)) - 1;
		role.quadrant = quadrant;
	}
1877
	for_each_gfn_sp(vcpu->kvm, sp, gfn) {
1878 1879
		if (!need_sync && sp->unsync)
			need_sync = true;
1880

1881 1882
		if (sp->role.word != role.word)
			continue;
1883

1884 1885
		if (sp->unsync && kvm_sync_page_transient(vcpu, sp))
			break;
1886

1887 1888
		mmu_page_add_parent_pte(vcpu, sp, parent_pte);
		if (sp->unsync_children) {
1889
			kvm_make_request(KVM_REQ_MMU_SYNC, vcpu);
1890 1891 1892
			kvm_mmu_mark_parents_unsync(sp);
		} else if (sp->unsync)
			kvm_mmu_mark_parents_unsync(sp);
1893

1894
		__clear_sp_write_flooding_count(sp);
1895 1896 1897
		trace_kvm_mmu_get_page(sp, false);
		return sp;
	}
A
Avi Kivity 已提交
1898
	++vcpu->kvm->stat.mmu_cache_miss;
1899
	sp = kvm_mmu_alloc_page(vcpu, parent_pte, direct);
1900 1901 1902 1903
	if (!sp)
		return sp;
	sp->gfn = gfn;
	sp->role = role;
1904 1905
	hlist_add_head(&sp->hash_link,
		&vcpu->kvm->arch.mmu_page_hash[kvm_page_table_hashfn(gfn)]);
1906
	if (!direct) {
1907 1908
		if (rmap_write_protect(vcpu->kvm, gfn))
			kvm_flush_remote_tlbs(vcpu->kvm);
1909 1910 1911
		if (level > PT_PAGE_TABLE_LEVEL && need_sync)
			kvm_sync_pages(vcpu, gfn);

1912 1913
		account_shadowed(vcpu->kvm, gfn);
	}
1914
	sp->mmu_valid_gen = vcpu->kvm->arch.mmu_valid_gen;
1915
	init_shadow_page_table(sp);
A
Avi Kivity 已提交
1916
	trace_kvm_mmu_get_page(sp, true);
1917
	return sp;
1918 1919
}

1920 1921 1922 1923 1924 1925
static void shadow_walk_init(struct kvm_shadow_walk_iterator *iterator,
			     struct kvm_vcpu *vcpu, u64 addr)
{
	iterator->addr = addr;
	iterator->shadow_addr = vcpu->arch.mmu.root_hpa;
	iterator->level = vcpu->arch.mmu.shadow_root_level;
1926 1927 1928 1929 1930 1931

	if (iterator->level == PT64_ROOT_LEVEL &&
	    vcpu->arch.mmu.root_level < PT64_ROOT_LEVEL &&
	    !vcpu->arch.mmu.direct_map)
		--iterator->level;

1932 1933 1934 1935 1936 1937 1938 1939 1940 1941 1942 1943 1944 1945
	if (iterator->level == PT32E_ROOT_LEVEL) {
		iterator->shadow_addr
			= vcpu->arch.mmu.pae_root[(addr >> 30) & 3];
		iterator->shadow_addr &= PT64_BASE_ADDR_MASK;
		--iterator->level;
		if (!iterator->shadow_addr)
			iterator->level = 0;
	}
}

static bool shadow_walk_okay(struct kvm_shadow_walk_iterator *iterator)
{
	if (iterator->level < PT_PAGE_TABLE_LEVEL)
		return false;
1946

1947 1948 1949 1950 1951
	iterator->index = SHADOW_PT_INDEX(iterator->addr, iterator->level);
	iterator->sptep	= ((u64 *)__va(iterator->shadow_addr)) + iterator->index;
	return true;
}

1952 1953
static void __shadow_walk_next(struct kvm_shadow_walk_iterator *iterator,
			       u64 spte)
1954
{
1955
	if (is_last_spte(spte, iterator->level)) {
1956 1957 1958 1959
		iterator->level = 0;
		return;
	}

1960
	iterator->shadow_addr = spte & PT64_BASE_ADDR_MASK;
1961 1962 1963
	--iterator->level;
}

1964 1965 1966 1967 1968
static void shadow_walk_next(struct kvm_shadow_walk_iterator *iterator)
{
	return __shadow_walk_next(iterator, *iterator->sptep);
}

1969 1970 1971 1972
static void link_shadow_page(u64 *sptep, struct kvm_mmu_page *sp)
{
	u64 spte;

X
Xiao Guangrong 已提交
1973 1974 1975
	spte = __pa(sp->spt) | PT_PRESENT_MASK | PT_WRITABLE_MASK |
	       shadow_user_mask | shadow_x_mask | shadow_accessed_mask;

1976
	mmu_spte_set(sptep, spte);
1977 1978
}

1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995
static void validate_direct_spte(struct kvm_vcpu *vcpu, u64 *sptep,
				   unsigned direct_access)
{
	if (is_shadow_present_pte(*sptep) && !is_large_pte(*sptep)) {
		struct kvm_mmu_page *child;

		/*
		 * For the direct sp, if the guest pte's dirty bit
		 * changed form clean to dirty, it will corrupt the
		 * sp's access: allow writable in the read-only sp,
		 * so we should update the spte at this point to get
		 * a new sp with the correct access.
		 */
		child = page_header(*sptep & PT64_BASE_ADDR_MASK);
		if (child->role.access == direct_access)
			return;

1996
		drop_parent_pte(child, sptep);
1997 1998 1999 2000
		kvm_flush_remote_tlbs(vcpu->kvm);
	}
}

X
Xiao Guangrong 已提交
2001
static bool mmu_page_zap_pte(struct kvm *kvm, struct kvm_mmu_page *sp,
2002 2003 2004 2005 2006 2007 2008
			     u64 *spte)
{
	u64 pte;
	struct kvm_mmu_page *child;

	pte = *spte;
	if (is_shadow_present_pte(pte)) {
X
Xiao Guangrong 已提交
2009
		if (is_last_spte(pte, sp->role.level)) {
2010
			drop_spte(kvm, spte);
X
Xiao Guangrong 已提交
2011 2012 2013
			if (is_large_pte(pte))
				--kvm->stat.lpages;
		} else {
2014
			child = page_header(pte & PT64_BASE_ADDR_MASK);
2015
			drop_parent_pte(child, spte);
2016
		}
X
Xiao Guangrong 已提交
2017 2018 2019 2020
		return true;
	}

	if (is_mmio_spte(pte))
2021
		mmu_spte_clear_no_track(spte);
2022

X
Xiao Guangrong 已提交
2023
	return false;
2024 2025
}

2026
static void kvm_mmu_page_unlink_children(struct kvm *kvm,
2027
					 struct kvm_mmu_page *sp)
2028
{
2029 2030
	unsigned i;

2031 2032
	for (i = 0; i < PT64_ENT_PER_PAGE; ++i)
		mmu_page_zap_pte(kvm, sp, sp->spt + i);
2033 2034
}

2035
static void kvm_mmu_put_page(struct kvm_mmu_page *sp, u64 *parent_pte)
2036
{
2037
	mmu_page_remove_parent_pte(sp, parent_pte);
2038 2039
}

2040
static void kvm_mmu_unlink_parents(struct kvm *kvm, struct kvm_mmu_page *sp)
2041
{
2042 2043
	u64 *sptep;
	struct rmap_iterator iter;
2044

2045 2046
	while ((sptep = rmap_get_first(sp->parent_ptes, &iter)))
		drop_parent_pte(sp, sptep);
2047 2048
}

2049
static int mmu_zap_unsync_children(struct kvm *kvm,
2050 2051
				   struct kvm_mmu_page *parent,
				   struct list_head *invalid_list)
2052
{
2053 2054 2055
	int i, zapped = 0;
	struct mmu_page_path parents;
	struct kvm_mmu_pages pages;
2056

2057
	if (parent->role.level == PT_PAGE_TABLE_LEVEL)
2058
		return 0;
2059 2060 2061 2062 2063 2064

	kvm_mmu_pages_init(parent, &parents, &pages);
	while (mmu_unsync_walk(parent, &pages)) {
		struct kvm_mmu_page *sp;

		for_each_sp(pages, sp, parents, i) {
2065
			kvm_mmu_prepare_zap_page(kvm, sp, invalid_list);
2066
			mmu_pages_clear_parents(&parents);
2067
			zapped++;
2068 2069 2070 2071 2072
		}
		kvm_mmu_pages_init(parent, &parents, &pages);
	}

	return zapped;
2073 2074
}

2075 2076
static int kvm_mmu_prepare_zap_page(struct kvm *kvm, struct kvm_mmu_page *sp,
				    struct list_head *invalid_list)
2077
{
2078
	int ret;
A
Avi Kivity 已提交
2079

2080
	trace_kvm_mmu_prepare_zap_page(sp);
2081
	++kvm->stat.mmu_shadow_zapped;
2082
	ret = mmu_zap_unsync_children(kvm, sp, invalid_list);
2083
	kvm_mmu_page_unlink_children(kvm, sp);
2084
	kvm_mmu_unlink_parents(kvm, sp);
2085

2086
	if (!sp->role.invalid && !sp->role.direct)
A
Avi Kivity 已提交
2087
		unaccount_shadowed(kvm, sp->gfn);
2088

2089 2090
	if (sp->unsync)
		kvm_unlink_unsync_page(kvm, sp);
2091
	if (!sp->root_count) {
2092 2093
		/* Count self */
		ret++;
2094
		list_move(&sp->link, invalid_list);
2095
		kvm_mod_used_mmu_pages(kvm, -1);
2096
	} else {
A
Avi Kivity 已提交
2097
		list_move(&sp->link, &kvm->arch.active_mmu_pages);
2098 2099
		kvm_reload_remote_mmus(kvm);
	}
2100 2101

	sp->role.invalid = 1;
2102
	return ret;
2103 2104
}

2105 2106 2107
static void kvm_mmu_commit_zap_page(struct kvm *kvm,
				    struct list_head *invalid_list)
{
2108
	struct kvm_mmu_page *sp, *nsp;
2109 2110 2111 2112

	if (list_empty(invalid_list))
		return;

2113 2114 2115 2116 2117
	/*
	 * wmb: make sure everyone sees our modifications to the page tables
	 * rmb: make sure we see changes to vcpu->mode
	 */
	smp_mb();
X
Xiao Guangrong 已提交
2118

2119 2120 2121 2122 2123
	/*
	 * Wait for all vcpus to exit guest mode and/or lockless shadow
	 * page table walks.
	 */
	kvm_flush_remote_tlbs(kvm);
2124

2125
	list_for_each_entry_safe(sp, nsp, invalid_list, link) {
2126
		WARN_ON(!sp->role.invalid || sp->root_count);
2127
		kvm_mmu_free_page(sp);
2128
	}
2129 2130
}

2131 2132 2133 2134 2135 2136 2137 2138 2139 2140 2141 2142 2143 2144 2145
static bool prepare_zap_oldest_mmu_page(struct kvm *kvm,
					struct list_head *invalid_list)
{
	struct kvm_mmu_page *sp;

	if (list_empty(&kvm->arch.active_mmu_pages))
		return false;

	sp = list_entry(kvm->arch.active_mmu_pages.prev,
			struct kvm_mmu_page, link);
	kvm_mmu_prepare_zap_page(kvm, sp, invalid_list);

	return true;
}

2146 2147
/*
 * Changing the number of mmu pages allocated to the vm
2148
 * Note: if goal_nr_mmu_pages is too small, you will get dead lock
2149
 */
2150
void kvm_mmu_change_mmu_pages(struct kvm *kvm, unsigned int goal_nr_mmu_pages)
2151
{
2152
	LIST_HEAD(invalid_list);
2153

2154 2155
	spin_lock(&kvm->mmu_lock);

2156
	if (kvm->arch.n_used_mmu_pages > goal_nr_mmu_pages) {
2157 2158 2159 2160
		/* Need to free some mmu pages to achieve the goal. */
		while (kvm->arch.n_used_mmu_pages > goal_nr_mmu_pages)
			if (!prepare_zap_oldest_mmu_page(kvm, &invalid_list))
				break;
2161

2162
		kvm_mmu_commit_zap_page(kvm, &invalid_list);
2163
		goal_nr_mmu_pages = kvm->arch.n_used_mmu_pages;
2164 2165
	}

2166
	kvm->arch.n_max_mmu_pages = goal_nr_mmu_pages;
2167 2168

	spin_unlock(&kvm->mmu_lock);
2169 2170
}

2171
int kvm_mmu_unprotect_page(struct kvm *kvm, gfn_t gfn)
2172
{
2173
	struct kvm_mmu_page *sp;
2174
	LIST_HEAD(invalid_list);
2175 2176
	int r;

2177
	pgprintk("%s: looking for gfn %llx\n", __func__, gfn);
2178
	r = 0;
2179
	spin_lock(&kvm->mmu_lock);
2180
	for_each_gfn_indirect_valid_sp(kvm, sp, gfn) {
2181
		pgprintk("%s: gfn %llx role %x\n", __func__, gfn,
2182 2183
			 sp->role.word);
		r = 1;
2184
		kvm_mmu_prepare_zap_page(kvm, sp, &invalid_list);
2185
	}
2186
	kvm_mmu_commit_zap_page(kvm, &invalid_list);
2187 2188
	spin_unlock(&kvm->mmu_lock);

2189
	return r;
2190
}
2191
EXPORT_SYMBOL_GPL(kvm_mmu_unprotect_page);
2192

2193 2194 2195 2196 2197 2198 2199 2200 2201 2202 2203 2204 2205 2206 2207 2208 2209 2210 2211 2212 2213 2214 2215 2216 2217 2218 2219 2220 2221 2222 2223 2224 2225 2226 2227 2228 2229 2230 2231 2232 2233 2234 2235 2236 2237 2238 2239 2240 2241 2242 2243 2244 2245 2246 2247 2248 2249 2250 2251 2252 2253 2254 2255 2256 2257 2258 2259 2260 2261 2262 2263 2264 2265 2266 2267 2268 2269 2270 2271 2272 2273 2274 2275 2276 2277 2278 2279 2280 2281 2282 2283 2284 2285
/*
 * The function is based on mtrr_type_lookup() in
 * arch/x86/kernel/cpu/mtrr/generic.c
 */
static int get_mtrr_type(struct mtrr_state_type *mtrr_state,
			 u64 start, u64 end)
{
	int i;
	u64 base, mask;
	u8 prev_match, curr_match;
	int num_var_ranges = KVM_NR_VAR_MTRR;

	if (!mtrr_state->enabled)
		return 0xFF;

	/* Make end inclusive end, instead of exclusive */
	end--;

	/* Look in fixed ranges. Just return the type as per start */
	if (mtrr_state->have_fixed && (start < 0x100000)) {
		int idx;

		if (start < 0x80000) {
			idx = 0;
			idx += (start >> 16);
			return mtrr_state->fixed_ranges[idx];
		} else if (start < 0xC0000) {
			idx = 1 * 8;
			idx += ((start - 0x80000) >> 14);
			return mtrr_state->fixed_ranges[idx];
		} else if (start < 0x1000000) {
			idx = 3 * 8;
			idx += ((start - 0xC0000) >> 12);
			return mtrr_state->fixed_ranges[idx];
		}
	}

	/*
	 * Look in variable ranges
	 * Look of multiple ranges matching this address and pick type
	 * as per MTRR precedence
	 */
	if (!(mtrr_state->enabled & 2))
		return mtrr_state->def_type;

	prev_match = 0xFF;
	for (i = 0; i < num_var_ranges; ++i) {
		unsigned short start_state, end_state;

		if (!(mtrr_state->var_ranges[i].mask_lo & (1 << 11)))
			continue;

		base = (((u64)mtrr_state->var_ranges[i].base_hi) << 32) +
		       (mtrr_state->var_ranges[i].base_lo & PAGE_MASK);
		mask = (((u64)mtrr_state->var_ranges[i].mask_hi) << 32) +
		       (mtrr_state->var_ranges[i].mask_lo & PAGE_MASK);

		start_state = ((start & mask) == (base & mask));
		end_state = ((end & mask) == (base & mask));
		if (start_state != end_state)
			return 0xFE;

		if ((start & mask) != (base & mask))
			continue;

		curr_match = mtrr_state->var_ranges[i].base_lo & 0xff;
		if (prev_match == 0xFF) {
			prev_match = curr_match;
			continue;
		}

		if (prev_match == MTRR_TYPE_UNCACHABLE ||
		    curr_match == MTRR_TYPE_UNCACHABLE)
			return MTRR_TYPE_UNCACHABLE;

		if ((prev_match == MTRR_TYPE_WRBACK &&
		     curr_match == MTRR_TYPE_WRTHROUGH) ||
		    (prev_match == MTRR_TYPE_WRTHROUGH &&
		     curr_match == MTRR_TYPE_WRBACK)) {
			prev_match = MTRR_TYPE_WRTHROUGH;
			curr_match = MTRR_TYPE_WRTHROUGH;
		}

		if (prev_match != curr_match)
			return MTRR_TYPE_UNCACHABLE;
	}

	if (prev_match != 0xFF)
		return prev_match;

	return mtrr_state->def_type;
}

2286
u8 kvm_get_guest_memory_type(struct kvm_vcpu *vcpu, gfn_t gfn)
2287 2288 2289 2290 2291 2292 2293 2294 2295
{
	u8 mtrr;

	mtrr = get_mtrr_type(&vcpu->arch.mtrr_state, gfn << PAGE_SHIFT,
			     (gfn << PAGE_SHIFT) + PAGE_SIZE);
	if (mtrr == 0xfe || mtrr == 0xff)
		mtrr = MTRR_TYPE_WRBACK;
	return mtrr;
}
2296
EXPORT_SYMBOL_GPL(kvm_get_guest_memory_type);
2297

2298 2299 2300 2301 2302 2303 2304 2305 2306 2307
static void __kvm_unsync_page(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp)
{
	trace_kvm_mmu_unsync_page(sp);
	++vcpu->kvm->stat.mmu_unsync;
	sp->unsync = 1;

	kvm_mmu_mark_parents_unsync(sp);
}

static void kvm_unsync_pages(struct kvm_vcpu *vcpu,  gfn_t gfn)
2308 2309
{
	struct kvm_mmu_page *s;
2310

2311
	for_each_gfn_indirect_valid_sp(vcpu->kvm, s, gfn) {
2312
		if (s->unsync)
2313
			continue;
2314 2315
		WARN_ON(s->role.level != PT_PAGE_TABLE_LEVEL);
		__kvm_unsync_page(vcpu, s);
2316 2317 2318 2319 2320 2321
	}
}

static int mmu_need_write_protect(struct kvm_vcpu *vcpu, gfn_t gfn,
				  bool can_unsync)
{
2322 2323 2324
	struct kvm_mmu_page *s;
	bool need_unsync = false;

2325
	for_each_gfn_indirect_valid_sp(vcpu->kvm, s, gfn) {
2326 2327 2328
		if (!can_unsync)
			return 1;

2329
		if (s->role.level != PT_PAGE_TABLE_LEVEL)
2330
			return 1;
2331

G
Gleb Natapov 已提交
2332
		if (!s->unsync)
2333
			need_unsync = true;
2334
	}
2335 2336
	if (need_unsync)
		kvm_unsync_pages(vcpu, gfn);
2337 2338 2339
	return 0;
}

A
Avi Kivity 已提交
2340
static int set_spte(struct kvm_vcpu *vcpu, u64 *sptep,
2341
		    unsigned pte_access, int level,
2342
		    gfn_t gfn, pfn_t pfn, bool speculative,
2343
		    bool can_unsync, bool host_writable)
2344
{
2345
	u64 spte;
M
Marcelo Tosatti 已提交
2346
	int ret = 0;
S
Sheng Yang 已提交
2347

2348 2349 2350
	if (set_mmio_spte(sptep, gfn, pfn, pte_access))
		return 0;

2351
	spte = PT_PRESENT_MASK;
2352
	if (!speculative)
2353
		spte |= shadow_accessed_mask;
2354

S
Sheng Yang 已提交
2355 2356 2357 2358
	if (pte_access & ACC_EXEC_MASK)
		spte |= shadow_x_mask;
	else
		spte |= shadow_nx_mask;
2359

2360
	if (pte_access & ACC_USER_MASK)
S
Sheng Yang 已提交
2361
		spte |= shadow_user_mask;
2362

2363
	if (level > PT_PAGE_TABLE_LEVEL)
M
Marcelo Tosatti 已提交
2364
		spte |= PT_PAGE_SIZE_MASK;
2365
	if (tdp_enabled)
2366 2367
		spte |= kvm_x86_ops->get_mt_mask(vcpu, gfn,
			kvm_is_mmio_pfn(pfn));
2368

2369
	if (host_writable)
2370
		spte |= SPTE_HOST_WRITEABLE;
2371 2372
	else
		pte_access &= ~ACC_WRITE_MASK;
2373

2374
	spte |= (u64)pfn << PAGE_SHIFT;
2375

2376
	if (pte_access & ACC_WRITE_MASK) {
2377

X
Xiao Guangrong 已提交
2378
		/*
2379 2380 2381 2382
		 * Other vcpu creates new sp in the window between
		 * mapping_level() and acquiring mmu-lock. We can
		 * allow guest to retry the access, the mapping can
		 * be fixed if guest refault.
X
Xiao Guangrong 已提交
2383
		 */
2384
		if (level > PT_PAGE_TABLE_LEVEL &&
X
Xiao Guangrong 已提交
2385
		    has_wrprotected_page(vcpu->kvm, gfn, level))
A
Avi Kivity 已提交
2386
			goto done;
2387

2388
		spte |= PT_WRITABLE_MASK | SPTE_MMU_WRITEABLE;
2389

2390 2391 2392 2393 2394 2395
		/*
		 * Optimization: for pte sync, if spte was writable the hash
		 * lookup is unnecessary (and expensive). Write protection
		 * is responsibility of mmu_get_page / kvm_sync_page.
		 * Same reasoning can be applied to dirty page accounting.
		 */
2396
		if (!can_unsync && is_writable_pte(*sptep))
2397 2398
			goto set_pte;

2399
		if (mmu_need_write_protect(vcpu, gfn, can_unsync)) {
2400
			pgprintk("%s: found shadow page for %llx, marking ro\n",
2401
				 __func__, gfn);
M
Marcelo Tosatti 已提交
2402
			ret = 1;
2403
			pte_access &= ~ACC_WRITE_MASK;
2404
			spte &= ~(PT_WRITABLE_MASK | SPTE_MMU_WRITEABLE);
2405 2406 2407 2408 2409 2410
		}
	}

	if (pte_access & ACC_WRITE_MASK)
		mark_page_dirty(vcpu->kvm, gfn);

2411
set_pte:
2412
	if (mmu_spte_update(sptep, spte))
2413
		kvm_flush_remote_tlbs(vcpu->kvm);
A
Avi Kivity 已提交
2414
done:
M
Marcelo Tosatti 已提交
2415 2416 2417
	return ret;
}

A
Avi Kivity 已提交
2418
static void mmu_set_spte(struct kvm_vcpu *vcpu, u64 *sptep,
2419 2420 2421
			 unsigned pte_access, int write_fault, int *emulate,
			 int level, gfn_t gfn, pfn_t pfn, bool speculative,
			 bool host_writable)
M
Marcelo Tosatti 已提交
2422 2423
{
	int was_rmapped = 0;
2424
	int rmap_count;
M
Marcelo Tosatti 已提交
2425

2426 2427
	pgprintk("%s: spte %llx write_fault %d gfn %llx\n", __func__,
		 *sptep, write_fault, gfn);
M
Marcelo Tosatti 已提交
2428

A
Avi Kivity 已提交
2429
	if (is_rmap_spte(*sptep)) {
M
Marcelo Tosatti 已提交
2430 2431 2432 2433
		/*
		 * If we overwrite a PTE page pointer with a 2MB PMD, unlink
		 * the parent of the now unreachable PTE.
		 */
2434 2435
		if (level > PT_PAGE_TABLE_LEVEL &&
		    !is_large_pte(*sptep)) {
M
Marcelo Tosatti 已提交
2436
			struct kvm_mmu_page *child;
A
Avi Kivity 已提交
2437
			u64 pte = *sptep;
M
Marcelo Tosatti 已提交
2438 2439

			child = page_header(pte & PT64_BASE_ADDR_MASK);
2440
			drop_parent_pte(child, sptep);
2441
			kvm_flush_remote_tlbs(vcpu->kvm);
A
Avi Kivity 已提交
2442
		} else if (pfn != spte_to_pfn(*sptep)) {
2443
			pgprintk("hfn old %llx new %llx\n",
A
Avi Kivity 已提交
2444
				 spte_to_pfn(*sptep), pfn);
2445
			drop_spte(vcpu->kvm, sptep);
2446
			kvm_flush_remote_tlbs(vcpu->kvm);
2447 2448
		} else
			was_rmapped = 1;
M
Marcelo Tosatti 已提交
2449
	}
2450

2451 2452
	if (set_spte(vcpu, sptep, pte_access, level, gfn, pfn, speculative,
	      true, host_writable)) {
M
Marcelo Tosatti 已提交
2453
		if (write_fault)
2454
			*emulate = 1;
2455
		kvm_mmu_flush_tlb(vcpu);
2456
	}
M
Marcelo Tosatti 已提交
2457

2458 2459 2460
	if (unlikely(is_mmio_spte(*sptep) && emulate))
		*emulate = 1;

A
Avi Kivity 已提交
2461
	pgprintk("%s: setting spte %llx\n", __func__, *sptep);
2462
	pgprintk("instantiating %s PTE (%s) at %llx (%llx) addr %p\n",
A
Avi Kivity 已提交
2463
		 is_large_pte(*sptep)? "2MB" : "4kB",
2464 2465
		 *sptep & PT_PRESENT_MASK ?"RW":"R", gfn,
		 *sptep, sptep);
A
Avi Kivity 已提交
2466
	if (!was_rmapped && is_large_pte(*sptep))
M
Marcelo Tosatti 已提交
2467 2468
		++vcpu->kvm->stat.lpages;

2469 2470 2471 2472 2473 2474
	if (is_shadow_present_pte(*sptep)) {
		if (!was_rmapped) {
			rmap_count = rmap_add(vcpu, sptep, gfn);
			if (rmap_count > RMAP_RECYCLE_THRESHOLD)
				rmap_recycle(vcpu, sptep, gfn);
		}
2475
	}
2476

X
Xiao Guangrong 已提交
2477
	kvm_release_pfn_clean(pfn);
2478 2479
}

A
Avi Kivity 已提交
2480 2481
static void nonpaging_new_cr3(struct kvm_vcpu *vcpu)
{
2482
	mmu_free_roots(vcpu);
A
Avi Kivity 已提交
2483 2484
}

2485 2486 2487 2488 2489 2490 2491 2492
static bool is_rsvd_bits_set(struct kvm_mmu *mmu, u64 gpte, int level)
{
	int bit7;

	bit7 = (gpte >> 7) & 1;
	return (gpte & mmu->rsvd_bits_mask[bit7][level-1]) != 0;
}

2493 2494 2495 2496 2497
static pfn_t pte_prefetch_gfn_to_pfn(struct kvm_vcpu *vcpu, gfn_t gfn,
				     bool no_dirty_log)
{
	struct kvm_memory_slot *slot;

2498
	slot = gfn_to_memslot_dirty_bitmap(vcpu, gfn, no_dirty_log);
2499
	if (!slot)
2500
		return KVM_PFN_ERR_FAULT;
2501

2502
	return gfn_to_pfn_memslot_atomic(slot, gfn);
2503 2504
}

2505 2506 2507 2508 2509 2510 2511 2512 2513 2514 2515 2516 2517 2518 2519 2520 2521 2522 2523 2524
static bool prefetch_invalid_gpte(struct kvm_vcpu *vcpu,
				  struct kvm_mmu_page *sp, u64 *spte,
				  u64 gpte)
{
	if (is_rsvd_bits_set(&vcpu->arch.mmu, gpte, PT_PAGE_TABLE_LEVEL))
		goto no_present;

	if (!is_present_gpte(gpte))
		goto no_present;

	if (!(gpte & PT_ACCESSED_MASK))
		goto no_present;

	return false;

no_present:
	drop_spte(vcpu->kvm, spte);
	return true;
}

2525 2526 2527 2528 2529 2530 2531 2532 2533 2534
static int direct_pte_prefetch_many(struct kvm_vcpu *vcpu,
				    struct kvm_mmu_page *sp,
				    u64 *start, u64 *end)
{
	struct page *pages[PTE_PREFETCH_NUM];
	unsigned access = sp->role.access;
	int i, ret;
	gfn_t gfn;

	gfn = kvm_mmu_page_get_gfn(sp, start - sp->spt);
2535
	if (!gfn_to_memslot_dirty_bitmap(vcpu, gfn, access & ACC_WRITE_MASK))
2536 2537 2538 2539 2540 2541 2542
		return -1;

	ret = gfn_to_page_many_atomic(vcpu->kvm, gfn, pages, end - start);
	if (ret <= 0)
		return -1;

	for (i = 0; i < ret; i++, gfn++, start++)
2543
		mmu_set_spte(vcpu, start, access, 0, NULL,
2544 2545
			     sp->role.level, gfn, page_to_pfn(pages[i]),
			     true, true);
2546 2547 2548 2549 2550 2551 2552 2553 2554 2555 2556 2557 2558 2559 2560 2561

	return 0;
}

static void __direct_pte_prefetch(struct kvm_vcpu *vcpu,
				  struct kvm_mmu_page *sp, u64 *sptep)
{
	u64 *spte, *start = NULL;
	int i;

	WARN_ON(!sp->role.direct);

	i = (sptep - sp->spt) & ~(PTE_PREFETCH_NUM - 1);
	spte = sp->spt + i;

	for (i = 0; i < PTE_PREFETCH_NUM; i++, spte++) {
2562
		if (is_shadow_present_pte(*spte) || spte == sptep) {
2563 2564 2565 2566 2567 2568 2569 2570 2571 2572 2573 2574 2575 2576 2577 2578 2579 2580 2581 2582 2583 2584 2585 2586 2587 2588 2589 2590 2591 2592
			if (!start)
				continue;
			if (direct_pte_prefetch_many(vcpu, sp, start, spte) < 0)
				break;
			start = NULL;
		} else if (!start)
			start = spte;
	}
}

static void direct_pte_prefetch(struct kvm_vcpu *vcpu, u64 *sptep)
{
	struct kvm_mmu_page *sp;

	/*
	 * Since it's no accessed bit on EPT, it's no way to
	 * distinguish between actually accessed translations
	 * and prefetched, so disable pte prefetch if EPT is
	 * enabled.
	 */
	if (!shadow_accessed_mask)
		return;

	sp = page_header(__pa(sptep));
	if (sp->role.level > PT_PAGE_TABLE_LEVEL)
		return;

	__direct_pte_prefetch(vcpu, sp, sptep);
}

2593
static int __direct_map(struct kvm_vcpu *vcpu, gpa_t v, int write,
2594 2595
			int map_writable, int level, gfn_t gfn, pfn_t pfn,
			bool prefault)
2596
{
2597
	struct kvm_shadow_walk_iterator iterator;
2598
	struct kvm_mmu_page *sp;
2599
	int emulate = 0;
2600
	gfn_t pseudo_gfn;
A
Avi Kivity 已提交
2601

2602
	for_each_shadow_entry(vcpu, (u64)gfn << PAGE_SHIFT, iterator) {
2603
		if (iterator.level == level) {
2604
			mmu_set_spte(vcpu, iterator.sptep, ACC_ALL,
2605 2606
				     write, &emulate, level, gfn, pfn,
				     prefault, map_writable);
2607
			direct_pte_prefetch(vcpu, iterator.sptep);
2608 2609
			++vcpu->stat.pf_fixed;
			break;
A
Avi Kivity 已提交
2610 2611
		}

2612
		if (!is_shadow_present_pte(*iterator.sptep)) {
2613 2614 2615 2616
			u64 base_addr = iterator.addr;

			base_addr &= PT64_LVL_ADDR_MASK(iterator.level);
			pseudo_gfn = base_addr >> PAGE_SHIFT;
2617 2618 2619
			sp = kvm_mmu_get_page(vcpu, pseudo_gfn, iterator.addr,
					      iterator.level - 1,
					      1, ACC_ALL, iterator.sptep);
2620

X
Xiao Guangrong 已提交
2621
			link_shadow_page(iterator.sptep, sp);
2622 2623
		}
	}
2624
	return emulate;
A
Avi Kivity 已提交
2625 2626
}

H
Huang Ying 已提交
2627
static void kvm_send_hwpoison_signal(unsigned long address, struct task_struct *tsk)
2628
{
H
Huang Ying 已提交
2629 2630 2631 2632 2633 2634 2635
	siginfo_t info;

	info.si_signo	= SIGBUS;
	info.si_errno	= 0;
	info.si_code	= BUS_MCEERR_AR;
	info.si_addr	= (void __user *)address;
	info.si_addr_lsb = PAGE_SHIFT;
2636

H
Huang Ying 已提交
2637
	send_sig_info(SIGBUS, &info, tsk);
2638 2639
}

2640
static int kvm_handle_bad_page(struct kvm_vcpu *vcpu, gfn_t gfn, pfn_t pfn)
2641
{
X
Xiao Guangrong 已提交
2642 2643 2644 2645 2646 2647 2648 2649 2650
	/*
	 * Do not cache the mmio info caused by writing the readonly gfn
	 * into the spte otherwise read access on readonly gfn also can
	 * caused mmio page fault and treat it as mmio access.
	 * Return 1 to tell kvm to emulate it.
	 */
	if (pfn == KVM_PFN_ERR_RO_FAULT)
		return 1;

2651
	if (pfn == KVM_PFN_ERR_HWPOISON) {
2652
		kvm_send_hwpoison_signal(gfn_to_hva(vcpu->kvm, gfn), current);
2653
		return 0;
2654
	}
2655

2656
	return -EFAULT;
2657 2658
}

2659 2660 2661 2662 2663 2664 2665 2666 2667 2668 2669 2670 2671
static void transparent_hugepage_adjust(struct kvm_vcpu *vcpu,
					gfn_t *gfnp, pfn_t *pfnp, int *levelp)
{
	pfn_t pfn = *pfnp;
	gfn_t gfn = *gfnp;
	int level = *levelp;

	/*
	 * Check if it's a transparent hugepage. If this would be an
	 * hugetlbfs page, level wouldn't be set to
	 * PT_PAGE_TABLE_LEVEL and there would be no adjustment done
	 * here.
	 */
2672
	if (!is_error_noslot_pfn(pfn) && !kvm_is_mmio_pfn(pfn) &&
2673 2674 2675 2676 2677 2678 2679 2680 2681 2682 2683 2684 2685 2686 2687 2688 2689 2690 2691 2692 2693
	    level == PT_PAGE_TABLE_LEVEL &&
	    PageTransCompound(pfn_to_page(pfn)) &&
	    !has_wrprotected_page(vcpu->kvm, gfn, PT_DIRECTORY_LEVEL)) {
		unsigned long mask;
		/*
		 * mmu_notifier_retry was successful and we hold the
		 * mmu_lock here, so the pmd can't become splitting
		 * from under us, and in turn
		 * __split_huge_page_refcount() can't run from under
		 * us and we can safely transfer the refcount from
		 * PG_tail to PG_head as we switch the pfn to tail to
		 * head.
		 */
		*levelp = level = PT_DIRECTORY_LEVEL;
		mask = KVM_PAGES_PER_HPAGE(level) - 1;
		VM_BUG_ON((gfn & mask) != (pfn & mask));
		if (pfn & mask) {
			gfn &= ~mask;
			*gfnp = gfn;
			kvm_release_pfn_clean(pfn);
			pfn &= ~mask;
2694
			kvm_get_pfn(pfn);
2695 2696 2697 2698 2699
			*pfnp = pfn;
		}
	}
}

2700 2701 2702 2703 2704 2705
static bool handle_abnormal_pfn(struct kvm_vcpu *vcpu, gva_t gva, gfn_t gfn,
				pfn_t pfn, unsigned access, int *ret_val)
{
	bool ret = true;

	/* The pfn is invalid, report the error! */
2706
	if (unlikely(is_error_pfn(pfn))) {
2707 2708 2709 2710
		*ret_val = kvm_handle_bad_page(vcpu, gfn, pfn);
		goto exit;
	}

2711
	if (unlikely(is_noslot_pfn(pfn)))
2712 2713 2714 2715 2716 2717 2718
		vcpu_cache_mmio_info(vcpu, gva, gfn, access);

	ret = false;
exit:
	return ret;
}

2719 2720 2721 2722 2723 2724 2725 2726 2727 2728 2729 2730 2731 2732 2733 2734 2735 2736 2737 2738 2739 2740 2741 2742 2743 2744 2745 2746 2747 2748 2749 2750 2751 2752 2753 2754 2755 2756 2757 2758 2759 2760 2761 2762 2763 2764 2765 2766 2767 2768 2769 2770 2771 2772 2773 2774 2775 2776 2777 2778 2779 2780 2781 2782 2783 2784 2785 2786 2787 2788 2789 2790 2791 2792 2793 2794 2795 2796 2797 2798 2799 2800 2801 2802 2803 2804 2805 2806 2807 2808 2809
static bool page_fault_can_be_fast(struct kvm_vcpu *vcpu, u32 error_code)
{
	/*
	 * #PF can be fast only if the shadow page table is present and it
	 * is caused by write-protect, that means we just need change the
	 * W bit of the spte which can be done out of mmu-lock.
	 */
	if (!(error_code & PFERR_PRESENT_MASK) ||
	      !(error_code & PFERR_WRITE_MASK))
		return false;

	return true;
}

static bool
fast_pf_fix_direct_spte(struct kvm_vcpu *vcpu, u64 *sptep, u64 spte)
{
	struct kvm_mmu_page *sp = page_header(__pa(sptep));
	gfn_t gfn;

	WARN_ON(!sp->role.direct);

	/*
	 * The gfn of direct spte is stable since it is calculated
	 * by sp->gfn.
	 */
	gfn = kvm_mmu_page_get_gfn(sp, sptep - sp->spt);

	if (cmpxchg64(sptep, spte, spte | PT_WRITABLE_MASK) == spte)
		mark_page_dirty(vcpu->kvm, gfn);

	return true;
}

/*
 * Return value:
 * - true: let the vcpu to access on the same address again.
 * - false: let the real page fault path to fix it.
 */
static bool fast_page_fault(struct kvm_vcpu *vcpu, gva_t gva, int level,
			    u32 error_code)
{
	struct kvm_shadow_walk_iterator iterator;
	bool ret = false;
	u64 spte = 0ull;

	if (!page_fault_can_be_fast(vcpu, error_code))
		return false;

	walk_shadow_page_lockless_begin(vcpu);
	for_each_shadow_entry_lockless(vcpu, gva, iterator, spte)
		if (!is_shadow_present_pte(spte) || iterator.level < level)
			break;

	/*
	 * If the mapping has been changed, let the vcpu fault on the
	 * same address again.
	 */
	if (!is_rmap_spte(spte)) {
		ret = true;
		goto exit;
	}

	if (!is_last_spte(spte, level))
		goto exit;

	/*
	 * Check if it is a spurious fault caused by TLB lazily flushed.
	 *
	 * Need not check the access of upper level table entries since
	 * they are always ACC_ALL.
	 */
	 if (is_writable_pte(spte)) {
		ret = true;
		goto exit;
	}

	/*
	 * Currently, to simplify the code, only the spte write-protected
	 * by dirty-log can be fast fixed.
	 */
	if (!spte_is_locklessly_modifiable(spte))
		goto exit;

	/*
	 * Currently, fast page fault only works for direct mapping since
	 * the gfn is not stable for indirect shadow page.
	 * See Documentation/virtual/kvm/locking.txt to get more detail.
	 */
	ret = fast_pf_fix_direct_spte(vcpu, iterator.sptep, spte);
exit:
X
Xiao Guangrong 已提交
2810 2811
	trace_fast_page_fault(vcpu, gva, error_code, iterator.sptep,
			      spte, ret);
2812 2813 2814 2815 2816
	walk_shadow_page_lockless_end(vcpu);

	return ret;
}

2817
static bool try_async_pf(struct kvm_vcpu *vcpu, bool prefault, gfn_t gfn,
2818
			 gva_t gva, pfn_t *pfn, bool write, bool *writable);
2819
static void make_mmu_pages_available(struct kvm_vcpu *vcpu);
2820

2821 2822
static int nonpaging_map(struct kvm_vcpu *vcpu, gva_t v, u32 error_code,
			 gfn_t gfn, bool prefault)
2823 2824
{
	int r;
2825
	int level;
2826
	int force_pt_level;
2827
	pfn_t pfn;
2828
	unsigned long mmu_seq;
2829
	bool map_writable, write = error_code & PFERR_WRITE_MASK;
2830

2831 2832 2833 2834 2835 2836 2837 2838 2839 2840
	force_pt_level = mapping_level_dirty_bitmap(vcpu, gfn);
	if (likely(!force_pt_level)) {
		level = mapping_level(vcpu, gfn);
		/*
		 * This path builds a PAE pagetable - so we can map
		 * 2mb pages at maximum. Therefore check if the level
		 * is larger than that.
		 */
		if (level > PT_DIRECTORY_LEVEL)
			level = PT_DIRECTORY_LEVEL;
2841

2842 2843 2844
		gfn &= ~(KVM_PAGES_PER_HPAGE(level) - 1);
	} else
		level = PT_PAGE_TABLE_LEVEL;
M
Marcelo Tosatti 已提交
2845

2846 2847 2848
	if (fast_page_fault(vcpu, v, level, error_code))
		return 0;

2849
	mmu_seq = vcpu->kvm->mmu_notifier_seq;
2850
	smp_rmb();
2851

2852
	if (try_async_pf(vcpu, prefault, gfn, v, &pfn, write, &map_writable))
2853
		return 0;
2854

2855 2856
	if (handle_abnormal_pfn(vcpu, v, gfn, pfn, ACC_ALL, &r))
		return r;
2857

2858
	spin_lock(&vcpu->kvm->mmu_lock);
2859
	if (mmu_notifier_retry(vcpu->kvm, mmu_seq))
2860
		goto out_unlock;
2861
	make_mmu_pages_available(vcpu);
2862 2863
	if (likely(!force_pt_level))
		transparent_hugepage_adjust(vcpu, &gfn, &pfn, &level);
2864 2865
	r = __direct_map(vcpu, v, write, map_writable, level, gfn, pfn,
			 prefault);
2866 2867 2868
	spin_unlock(&vcpu->kvm->mmu_lock);


2869
	return r;
2870 2871 2872 2873 2874

out_unlock:
	spin_unlock(&vcpu->kvm->mmu_lock);
	kvm_release_pfn_clean(pfn);
	return 0;
2875 2876 2877
}


2878 2879 2880
static void mmu_free_roots(struct kvm_vcpu *vcpu)
{
	int i;
2881
	struct kvm_mmu_page *sp;
2882
	LIST_HEAD(invalid_list);
2883

2884
	if (!VALID_PAGE(vcpu->arch.mmu.root_hpa))
A
Avi Kivity 已提交
2885
		return;
2886

2887 2888 2889
	if (vcpu->arch.mmu.shadow_root_level == PT64_ROOT_LEVEL &&
	    (vcpu->arch.mmu.root_level == PT64_ROOT_LEVEL ||
	     vcpu->arch.mmu.direct_map)) {
2890
		hpa_t root = vcpu->arch.mmu.root_hpa;
2891

2892
		spin_lock(&vcpu->kvm->mmu_lock);
2893 2894
		sp = page_header(root);
		--sp->root_count;
2895 2896 2897 2898
		if (!sp->root_count && sp->role.invalid) {
			kvm_mmu_prepare_zap_page(vcpu->kvm, sp, &invalid_list);
			kvm_mmu_commit_zap_page(vcpu->kvm, &invalid_list);
		}
2899
		spin_unlock(&vcpu->kvm->mmu_lock);
2900
		vcpu->arch.mmu.root_hpa = INVALID_PAGE;
2901 2902
		return;
	}
2903 2904

	spin_lock(&vcpu->kvm->mmu_lock);
2905
	for (i = 0; i < 4; ++i) {
2906
		hpa_t root = vcpu->arch.mmu.pae_root[i];
2907

A
Avi Kivity 已提交
2908 2909
		if (root) {
			root &= PT64_BASE_ADDR_MASK;
2910 2911
			sp = page_header(root);
			--sp->root_count;
2912
			if (!sp->root_count && sp->role.invalid)
2913 2914
				kvm_mmu_prepare_zap_page(vcpu->kvm, sp,
							 &invalid_list);
A
Avi Kivity 已提交
2915
		}
2916
		vcpu->arch.mmu.pae_root[i] = INVALID_PAGE;
2917
	}
2918
	kvm_mmu_commit_zap_page(vcpu->kvm, &invalid_list);
2919
	spin_unlock(&vcpu->kvm->mmu_lock);
2920
	vcpu->arch.mmu.root_hpa = INVALID_PAGE;
2921 2922
}

2923 2924 2925 2926 2927
static int mmu_check_root(struct kvm_vcpu *vcpu, gfn_t root_gfn)
{
	int ret = 0;

	if (!kvm_is_visible_gfn(vcpu->kvm, root_gfn)) {
2928
		kvm_make_request(KVM_REQ_TRIPLE_FAULT, vcpu);
2929 2930 2931 2932 2933 2934
		ret = 1;
	}

	return ret;
}

2935 2936 2937
static int mmu_alloc_direct_roots(struct kvm_vcpu *vcpu)
{
	struct kvm_mmu_page *sp;
2938
	unsigned i;
2939 2940 2941

	if (vcpu->arch.mmu.shadow_root_level == PT64_ROOT_LEVEL) {
		spin_lock(&vcpu->kvm->mmu_lock);
2942
		make_mmu_pages_available(vcpu);
2943 2944 2945 2946 2947 2948 2949 2950 2951 2952 2953
		sp = kvm_mmu_get_page(vcpu, 0, 0, PT64_ROOT_LEVEL,
				      1, ACC_ALL, NULL);
		++sp->root_count;
		spin_unlock(&vcpu->kvm->mmu_lock);
		vcpu->arch.mmu.root_hpa = __pa(sp->spt);
	} else if (vcpu->arch.mmu.shadow_root_level == PT32E_ROOT_LEVEL) {
		for (i = 0; i < 4; ++i) {
			hpa_t root = vcpu->arch.mmu.pae_root[i];

			ASSERT(!VALID_PAGE(root));
			spin_lock(&vcpu->kvm->mmu_lock);
2954
			make_mmu_pages_available(vcpu);
2955 2956
			sp = kvm_mmu_get_page(vcpu, i << (30 - PAGE_SHIFT),
					      i << 30,
2957 2958 2959 2960 2961 2962 2963
					      PT32_ROOT_LEVEL, 1, ACC_ALL,
					      NULL);
			root = __pa(sp->spt);
			++sp->root_count;
			spin_unlock(&vcpu->kvm->mmu_lock);
			vcpu->arch.mmu.pae_root[i] = root | PT_PRESENT_MASK;
		}
2964
		vcpu->arch.mmu.root_hpa = __pa(vcpu->arch.mmu.pae_root);
2965 2966 2967 2968 2969 2970 2971
	} else
		BUG();

	return 0;
}

static int mmu_alloc_shadow_roots(struct kvm_vcpu *vcpu)
2972
{
2973
	struct kvm_mmu_page *sp;
2974 2975 2976
	u64 pdptr, pm_mask;
	gfn_t root_gfn;
	int i;
2977

2978
	root_gfn = vcpu->arch.mmu.get_cr3(vcpu) >> PAGE_SHIFT;
2979

2980 2981 2982 2983 2984 2985 2986 2987
	if (mmu_check_root(vcpu, root_gfn))
		return 1;

	/*
	 * Do we shadow a long mode page table? If so we need to
	 * write-protect the guests page table root.
	 */
	if (vcpu->arch.mmu.root_level == PT64_ROOT_LEVEL) {
2988
		hpa_t root = vcpu->arch.mmu.root_hpa;
2989 2990

		ASSERT(!VALID_PAGE(root));
2991

2992
		spin_lock(&vcpu->kvm->mmu_lock);
2993
		make_mmu_pages_available(vcpu);
2994 2995
		sp = kvm_mmu_get_page(vcpu, root_gfn, 0, PT64_ROOT_LEVEL,
				      0, ACC_ALL, NULL);
2996 2997
		root = __pa(sp->spt);
		++sp->root_count;
2998
		spin_unlock(&vcpu->kvm->mmu_lock);
2999
		vcpu->arch.mmu.root_hpa = root;
3000
		return 0;
3001
	}
3002

3003 3004
	/*
	 * We shadow a 32 bit page table. This may be a legacy 2-level
3005 3006
	 * or a PAE 3-level page table. In either case we need to be aware that
	 * the shadow page table may be a PAE or a long mode page table.
3007
	 */
3008 3009 3010 3011
	pm_mask = PT_PRESENT_MASK;
	if (vcpu->arch.mmu.shadow_root_level == PT64_ROOT_LEVEL)
		pm_mask |= PT_ACCESSED_MASK | PT_WRITABLE_MASK | PT_USER_MASK;

3012
	for (i = 0; i < 4; ++i) {
3013
		hpa_t root = vcpu->arch.mmu.pae_root[i];
3014 3015

		ASSERT(!VALID_PAGE(root));
3016
		if (vcpu->arch.mmu.root_level == PT32E_ROOT_LEVEL) {
3017
			pdptr = vcpu->arch.mmu.get_pdptr(vcpu, i);
3018
			if (!is_present_gpte(pdptr)) {
3019
				vcpu->arch.mmu.pae_root[i] = 0;
A
Avi Kivity 已提交
3020 3021
				continue;
			}
A
Avi Kivity 已提交
3022
			root_gfn = pdptr >> PAGE_SHIFT;
3023 3024
			if (mmu_check_root(vcpu, root_gfn))
				return 1;
3025
		}
3026
		spin_lock(&vcpu->kvm->mmu_lock);
3027
		make_mmu_pages_available(vcpu);
3028
		sp = kvm_mmu_get_page(vcpu, root_gfn, i << 30,
3029
				      PT32_ROOT_LEVEL, 0,
3030
				      ACC_ALL, NULL);
3031 3032
		root = __pa(sp->spt);
		++sp->root_count;
3033 3034
		spin_unlock(&vcpu->kvm->mmu_lock);

3035
		vcpu->arch.mmu.pae_root[i] = root | pm_mask;
3036
	}
3037
	vcpu->arch.mmu.root_hpa = __pa(vcpu->arch.mmu.pae_root);
3038 3039 3040 3041 3042 3043 3044 3045 3046 3047 3048 3049 3050 3051 3052 3053 3054 3055 3056 3057 3058 3059 3060 3061 3062 3063

	/*
	 * If we shadow a 32 bit page table with a long mode page
	 * table we enter this path.
	 */
	if (vcpu->arch.mmu.shadow_root_level == PT64_ROOT_LEVEL) {
		if (vcpu->arch.mmu.lm_root == NULL) {
			/*
			 * The additional page necessary for this is only
			 * allocated on demand.
			 */

			u64 *lm_root;

			lm_root = (void*)get_zeroed_page(GFP_KERNEL);
			if (lm_root == NULL)
				return 1;

			lm_root[0] = __pa(vcpu->arch.mmu.pae_root) | pm_mask;

			vcpu->arch.mmu.lm_root = lm_root;
		}

		vcpu->arch.mmu.root_hpa = __pa(vcpu->arch.mmu.lm_root);
	}

3064
	return 0;
3065 3066
}

3067 3068 3069 3070 3071 3072 3073 3074
static int mmu_alloc_roots(struct kvm_vcpu *vcpu)
{
	if (vcpu->arch.mmu.direct_map)
		return mmu_alloc_direct_roots(vcpu);
	else
		return mmu_alloc_shadow_roots(vcpu);
}

3075 3076 3077 3078 3079
static void mmu_sync_roots(struct kvm_vcpu *vcpu)
{
	int i;
	struct kvm_mmu_page *sp;

3080 3081 3082
	if (vcpu->arch.mmu.direct_map)
		return;

3083 3084
	if (!VALID_PAGE(vcpu->arch.mmu.root_hpa))
		return;
3085

3086
	vcpu_clear_mmio_info(vcpu, ~0ul);
3087
	kvm_mmu_audit(vcpu, AUDIT_PRE_SYNC);
3088
	if (vcpu->arch.mmu.root_level == PT64_ROOT_LEVEL) {
3089 3090 3091
		hpa_t root = vcpu->arch.mmu.root_hpa;
		sp = page_header(root);
		mmu_sync_children(vcpu, sp);
3092
		kvm_mmu_audit(vcpu, AUDIT_POST_SYNC);
3093 3094 3095 3096 3097
		return;
	}
	for (i = 0; i < 4; ++i) {
		hpa_t root = vcpu->arch.mmu.pae_root[i];

3098
		if (root && VALID_PAGE(root)) {
3099 3100 3101 3102 3103
			root &= PT64_BASE_ADDR_MASK;
			sp = page_header(root);
			mmu_sync_children(vcpu, sp);
		}
	}
3104
	kvm_mmu_audit(vcpu, AUDIT_POST_SYNC);
3105 3106 3107 3108 3109 3110
}

void kvm_mmu_sync_roots(struct kvm_vcpu *vcpu)
{
	spin_lock(&vcpu->kvm->mmu_lock);
	mmu_sync_roots(vcpu);
3111
	spin_unlock(&vcpu->kvm->mmu_lock);
3112 3113
}

3114
static gpa_t nonpaging_gva_to_gpa(struct kvm_vcpu *vcpu, gva_t vaddr,
3115
				  u32 access, struct x86_exception *exception)
A
Avi Kivity 已提交
3116
{
3117 3118
	if (exception)
		exception->error_code = 0;
A
Avi Kivity 已提交
3119 3120 3121
	return vaddr;
}

3122
static gpa_t nonpaging_gva_to_gpa_nested(struct kvm_vcpu *vcpu, gva_t vaddr,
3123 3124
					 u32 access,
					 struct x86_exception *exception)
3125
{
3126 3127
	if (exception)
		exception->error_code = 0;
3128 3129 3130
	return vcpu->arch.nested_mmu.translate_gpa(vcpu, vaddr, access);
}

3131 3132 3133 3134 3135 3136 3137 3138 3139 3140 3141 3142 3143 3144 3145 3146 3147 3148 3149 3150 3151 3152 3153 3154 3155 3156 3157 3158 3159 3160 3161 3162 3163 3164 3165 3166 3167 3168 3169 3170 3171 3172 3173 3174 3175 3176 3177 3178 3179 3180 3181 3182 3183 3184 3185 3186 3187
static bool quickly_check_mmio_pf(struct kvm_vcpu *vcpu, u64 addr, bool direct)
{
	if (direct)
		return vcpu_match_mmio_gpa(vcpu, addr);

	return vcpu_match_mmio_gva(vcpu, addr);
}


/*
 * On direct hosts, the last spte is only allows two states
 * for mmio page fault:
 *   - It is the mmio spte
 *   - It is zapped or it is being zapped.
 *
 * This function completely checks the spte when the last spte
 * is not the mmio spte.
 */
static bool check_direct_spte_mmio_pf(u64 spte)
{
	return __check_direct_spte_mmio_pf(spte);
}

static u64 walk_shadow_page_get_mmio_spte(struct kvm_vcpu *vcpu, u64 addr)
{
	struct kvm_shadow_walk_iterator iterator;
	u64 spte = 0ull;

	walk_shadow_page_lockless_begin(vcpu);
	for_each_shadow_entry_lockless(vcpu, addr, iterator, spte)
		if (!is_shadow_present_pte(spte))
			break;
	walk_shadow_page_lockless_end(vcpu);

	return spte;
}

/*
 * If it is a real mmio page fault, return 1 and emulat the instruction
 * directly, return 0 to let CPU fault again on the address, -1 is
 * returned if bug is detected.
 */
int handle_mmio_page_fault_common(struct kvm_vcpu *vcpu, u64 addr, bool direct)
{
	u64 spte;

	if (quickly_check_mmio_pf(vcpu, addr, direct))
		return 1;

	spte = walk_shadow_page_get_mmio_spte(vcpu, addr);

	if (is_mmio_spte(spte)) {
		gfn_t gfn = get_mmio_spte_gfn(spte);
		unsigned access = get_mmio_spte_access(spte);

		if (direct)
			addr = 0;
X
Xiao Guangrong 已提交
3188 3189

		trace_handle_mmio_page_fault(addr, gfn, access);
3190 3191 3192 3193 3194 3195 3196 3197 3198 3199 3200 3201 3202 3203 3204 3205 3206 3207 3208 3209 3210 3211 3212 3213 3214 3215 3216 3217 3218
		vcpu_cache_mmio_info(vcpu, addr, gfn, access);
		return 1;
	}

	/*
	 * It's ok if the gva is remapped by other cpus on shadow guest,
	 * it's a BUG if the gfn is not a mmio page.
	 */
	if (direct && !check_direct_spte_mmio_pf(spte))
		return -1;

	/*
	 * If the page table is zapped by other cpus, let CPU fault again on
	 * the address.
	 */
	return 0;
}
EXPORT_SYMBOL_GPL(handle_mmio_page_fault_common);

static int handle_mmio_page_fault(struct kvm_vcpu *vcpu, u64 addr,
				  u32 error_code, bool direct)
{
	int ret;

	ret = handle_mmio_page_fault_common(vcpu, addr, direct);
	WARN_ON(ret < 0);
	return ret;
}

A
Avi Kivity 已提交
3219
static int nonpaging_page_fault(struct kvm_vcpu *vcpu, gva_t gva,
3220
				u32 error_code, bool prefault)
A
Avi Kivity 已提交
3221
{
3222
	gfn_t gfn;
3223
	int r;
A
Avi Kivity 已提交
3224

3225
	pgprintk("%s: gva %lx error %x\n", __func__, gva, error_code);
3226 3227 3228 3229

	if (unlikely(error_code & PFERR_RSVD_MASK))
		return handle_mmio_page_fault(vcpu, gva, error_code, true);

3230 3231 3232
	r = mmu_topup_memory_caches(vcpu);
	if (r)
		return r;
3233

A
Avi Kivity 已提交
3234
	ASSERT(vcpu);
3235
	ASSERT(VALID_PAGE(vcpu->arch.mmu.root_hpa));
A
Avi Kivity 已提交
3236

3237
	gfn = gva >> PAGE_SHIFT;
A
Avi Kivity 已提交
3238

3239
	return nonpaging_map(vcpu, gva & PAGE_MASK,
3240
			     error_code, gfn, prefault);
A
Avi Kivity 已提交
3241 3242
}

3243
static int kvm_arch_setup_async_pf(struct kvm_vcpu *vcpu, gva_t gva, gfn_t gfn)
3244 3245
{
	struct kvm_arch_async_pf arch;
X
Xiao Guangrong 已提交
3246

3247
	arch.token = (vcpu->arch.apf.id++ << 12) | vcpu->vcpu_id;
3248
	arch.gfn = gfn;
3249
	arch.direct_map = vcpu->arch.mmu.direct_map;
X
Xiao Guangrong 已提交
3250
	arch.cr3 = vcpu->arch.mmu.get_cr3(vcpu);
3251 3252 3253 3254 3255 3256 3257 3258 3259 3260 3261 3262 3263

	return kvm_setup_async_pf(vcpu, gva, gfn, &arch);
}

static bool can_do_async_pf(struct kvm_vcpu *vcpu)
{
	if (unlikely(!irqchip_in_kernel(vcpu->kvm) ||
		     kvm_event_needs_reinjection(vcpu)))
		return false;

	return kvm_x86_ops->interrupt_allowed(vcpu);
}

3264
static bool try_async_pf(struct kvm_vcpu *vcpu, bool prefault, gfn_t gfn,
3265
			 gva_t gva, pfn_t *pfn, bool write, bool *writable)
3266 3267 3268
{
	bool async;

3269
	*pfn = gfn_to_pfn_async(vcpu->kvm, gfn, &async, write, writable);
3270 3271 3272 3273

	if (!async)
		return false; /* *pfn has correct page already */

3274
	if (!prefault && can_do_async_pf(vcpu)) {
3275
		trace_kvm_try_async_get_page(gva, gfn);
3276 3277 3278 3279 3280 3281 3282 3283
		if (kvm_find_async_pf_gfn(vcpu, gfn)) {
			trace_kvm_async_pf_doublefault(gva, gfn);
			kvm_make_request(KVM_REQ_APF_HALT, vcpu);
			return true;
		} else if (kvm_arch_setup_async_pf(vcpu, gva, gfn))
			return true;
	}

3284
	*pfn = gfn_to_pfn_prot(vcpu->kvm, gfn, write, writable);
3285 3286 3287 3288

	return false;
}

G
Gleb Natapov 已提交
3289
static int tdp_page_fault(struct kvm_vcpu *vcpu, gva_t gpa, u32 error_code,
3290
			  bool prefault)
3291
{
3292
	pfn_t pfn;
3293
	int r;
3294
	int level;
3295
	int force_pt_level;
M
Marcelo Tosatti 已提交
3296
	gfn_t gfn = gpa >> PAGE_SHIFT;
3297
	unsigned long mmu_seq;
3298 3299
	int write = error_code & PFERR_WRITE_MASK;
	bool map_writable;
3300 3301 3302 3303

	ASSERT(vcpu);
	ASSERT(VALID_PAGE(vcpu->arch.mmu.root_hpa));

3304 3305 3306
	if (unlikely(error_code & PFERR_RSVD_MASK))
		return handle_mmio_page_fault(vcpu, gpa, error_code, true);

3307 3308 3309 3310
	r = mmu_topup_memory_caches(vcpu);
	if (r)
		return r;

3311 3312 3313 3314 3315 3316
	force_pt_level = mapping_level_dirty_bitmap(vcpu, gfn);
	if (likely(!force_pt_level)) {
		level = mapping_level(vcpu, gfn);
		gfn &= ~(KVM_PAGES_PER_HPAGE(level) - 1);
	} else
		level = PT_PAGE_TABLE_LEVEL;
3317

3318 3319 3320
	if (fast_page_fault(vcpu, gpa, level, error_code))
		return 0;

3321
	mmu_seq = vcpu->kvm->mmu_notifier_seq;
3322
	smp_rmb();
3323

3324
	if (try_async_pf(vcpu, prefault, gfn, gpa, &pfn, write, &map_writable))
3325 3326
		return 0;

3327 3328 3329
	if (handle_abnormal_pfn(vcpu, 0, gfn, pfn, ACC_ALL, &r))
		return r;

3330
	spin_lock(&vcpu->kvm->mmu_lock);
3331
	if (mmu_notifier_retry(vcpu->kvm, mmu_seq))
3332
		goto out_unlock;
3333
	make_mmu_pages_available(vcpu);
3334 3335
	if (likely(!force_pt_level))
		transparent_hugepage_adjust(vcpu, &gfn, &pfn, &level);
3336
	r = __direct_map(vcpu, gpa, write, map_writable,
3337
			 level, gfn, pfn, prefault);
3338 3339 3340
	spin_unlock(&vcpu->kvm->mmu_lock);

	return r;
3341 3342 3343 3344 3345

out_unlock:
	spin_unlock(&vcpu->kvm->mmu_lock);
	kvm_release_pfn_clean(pfn);
	return 0;
3346 3347
}

A
Avi Kivity 已提交
3348 3349
static void nonpaging_free(struct kvm_vcpu *vcpu)
{
3350
	mmu_free_roots(vcpu);
A
Avi Kivity 已提交
3351 3352
}

3353 3354
static int nonpaging_init_context(struct kvm_vcpu *vcpu,
				  struct kvm_mmu *context)
A
Avi Kivity 已提交
3355 3356 3357 3358 3359
{
	context->new_cr3 = nonpaging_new_cr3;
	context->page_fault = nonpaging_page_fault;
	context->gva_to_gpa = nonpaging_gva_to_gpa;
	context->free = nonpaging_free;
3360
	context->sync_page = nonpaging_sync_page;
M
Marcelo Tosatti 已提交
3361
	context->invlpg = nonpaging_invlpg;
3362
	context->update_pte = nonpaging_update_pte;
3363
	context->root_level = 0;
A
Avi Kivity 已提交
3364
	context->shadow_root_level = PT32E_ROOT_LEVEL;
A
Avi Kivity 已提交
3365
	context->root_hpa = INVALID_PAGE;
3366
	context->direct_map = true;
3367
	context->nx = false;
A
Avi Kivity 已提交
3368 3369 3370
	return 0;
}

3371
void kvm_mmu_flush_tlb(struct kvm_vcpu *vcpu)
A
Avi Kivity 已提交
3372
{
A
Avi Kivity 已提交
3373
	++vcpu->stat.tlb_flush;
3374
	kvm_make_request(KVM_REQ_TLB_FLUSH, vcpu);
A
Avi Kivity 已提交
3375 3376 3377 3378
}

static void paging_new_cr3(struct kvm_vcpu *vcpu)
{
3379
	pgprintk("%s: cr3 %lx\n", __func__, kvm_read_cr3(vcpu));
3380
	mmu_free_roots(vcpu);
A
Avi Kivity 已提交
3381 3382
}

3383 3384
static unsigned long get_cr3(struct kvm_vcpu *vcpu)
{
3385
	return kvm_read_cr3(vcpu);
3386 3387
}

3388 3389
static void inject_page_fault(struct kvm_vcpu *vcpu,
			      struct x86_exception *fault)
A
Avi Kivity 已提交
3390
{
3391
	vcpu->arch.mmu.inject_page_fault(vcpu, fault);
A
Avi Kivity 已提交
3392 3393 3394 3395 3396 3397 3398
}

static void paging_free(struct kvm_vcpu *vcpu)
{
	nonpaging_free(vcpu);
}

3399 3400 3401 3402 3403 3404 3405 3406 3407 3408 3409 3410
static inline void protect_clean_gpte(unsigned *access, unsigned gpte)
{
	unsigned mask;

	BUILD_BUG_ON(PT_WRITABLE_MASK != ACC_WRITE_MASK);

	mask = (unsigned)~ACC_WRITE_MASK;
	/* Allow write access to dirty gptes */
	mask |= (gpte >> (PT_DIRTY_SHIFT - PT_WRITABLE_SHIFT)) & PT_WRITABLE_MASK;
	*access &= mask;
}

3411 3412 3413 3414 3415 3416 3417 3418 3419 3420 3421 3422 3423 3424 3425 3426 3427
static bool sync_mmio_spte(u64 *sptep, gfn_t gfn, unsigned access,
			   int *nr_present)
{
	if (unlikely(is_mmio_spte(*sptep))) {
		if (gfn != get_mmio_spte_gfn(*sptep)) {
			mmu_spte_clear_no_track(sptep);
			return true;
		}

		(*nr_present)++;
		mark_mmio_spte(sptep, gfn, access);
		return true;
	}

	return false;
}

3428 3429 3430 3431 3432 3433 3434 3435 3436 3437
static inline unsigned gpte_access(struct kvm_vcpu *vcpu, u64 gpte)
{
	unsigned access;

	access = (gpte & (PT_WRITABLE_MASK | PT_USER_MASK)) | ACC_EXEC_MASK;
	access &= ~(gpte >> PT64_NX_SHIFT);

	return access;
}

A
Avi Kivity 已提交
3438 3439 3440 3441 3442 3443 3444 3445 3446
static inline bool is_last_gpte(struct kvm_mmu *mmu, unsigned level, unsigned gpte)
{
	unsigned index;

	index = level - 1;
	index |= (gpte & PT_PAGE_SIZE_MASK) >> (PT_PAGE_SIZE_SHIFT - 2);
	return mmu->last_pte_bitmap & (1 << index);
}

A
Avi Kivity 已提交
3447 3448 3449 3450 3451 3452 3453 3454
#define PTTYPE 64
#include "paging_tmpl.h"
#undef PTTYPE

#define PTTYPE 32
#include "paging_tmpl.h"
#undef PTTYPE

3455
static void reset_rsvds_bits_mask(struct kvm_vcpu *vcpu,
3456
				  struct kvm_mmu *context)
3457 3458 3459 3460
{
	int maxphyaddr = cpuid_maxphyaddr(vcpu);
	u64 exb_bit_rsvd = 0;

3461
	if (!context->nx)
3462
		exb_bit_rsvd = rsvd_bits(63, 63);
3463
	switch (context->root_level) {
3464 3465 3466 3467
	case PT32_ROOT_LEVEL:
		/* no rsvd bits for 2 level 4K page table entries */
		context->rsvd_bits_mask[0][1] = 0;
		context->rsvd_bits_mask[0][0] = 0;
3468 3469 3470 3471 3472 3473 3474
		context->rsvd_bits_mask[1][0] = context->rsvd_bits_mask[0][0];

		if (!is_pse(vcpu)) {
			context->rsvd_bits_mask[1][1] = 0;
			break;
		}

3475 3476 3477 3478 3479 3480 3481 3482
		if (is_cpuid_PSE36())
			/* 36bits PSE 4MB page */
			context->rsvd_bits_mask[1][1] = rsvd_bits(17, 21);
		else
			/* 32 bits PSE 4MB page */
			context->rsvd_bits_mask[1][1] = rsvd_bits(13, 21);
		break;
	case PT32E_ROOT_LEVEL:
3483 3484 3485
		context->rsvd_bits_mask[0][2] =
			rsvd_bits(maxphyaddr, 63) |
			rsvd_bits(7, 8) | rsvd_bits(1, 2);	/* PDPTE */
3486
		context->rsvd_bits_mask[0][1] = exb_bit_rsvd |
3487
			rsvd_bits(maxphyaddr, 62);	/* PDE */
3488 3489 3490 3491 3492
		context->rsvd_bits_mask[0][0] = exb_bit_rsvd |
			rsvd_bits(maxphyaddr, 62); 	/* PTE */
		context->rsvd_bits_mask[1][1] = exb_bit_rsvd |
			rsvd_bits(maxphyaddr, 62) |
			rsvd_bits(13, 20);		/* large page */
3493
		context->rsvd_bits_mask[1][0] = context->rsvd_bits_mask[0][0];
3494 3495 3496 3497 3498 3499 3500
		break;
	case PT64_ROOT_LEVEL:
		context->rsvd_bits_mask[0][3] = exb_bit_rsvd |
			rsvd_bits(maxphyaddr, 51) | rsvd_bits(7, 8);
		context->rsvd_bits_mask[0][2] = exb_bit_rsvd |
			rsvd_bits(maxphyaddr, 51) | rsvd_bits(7, 8);
		context->rsvd_bits_mask[0][1] = exb_bit_rsvd |
3501
			rsvd_bits(maxphyaddr, 51);
3502 3503 3504
		context->rsvd_bits_mask[0][0] = exb_bit_rsvd |
			rsvd_bits(maxphyaddr, 51);
		context->rsvd_bits_mask[1][3] = context->rsvd_bits_mask[0][3];
3505 3506 3507
		context->rsvd_bits_mask[1][2] = exb_bit_rsvd |
			rsvd_bits(maxphyaddr, 51) |
			rsvd_bits(13, 29);
3508
		context->rsvd_bits_mask[1][1] = exb_bit_rsvd |
3509 3510
			rsvd_bits(maxphyaddr, 51) |
			rsvd_bits(13, 20);		/* large page */
3511
		context->rsvd_bits_mask[1][0] = context->rsvd_bits_mask[0][0];
3512 3513 3514 3515
		break;
	}
}

3516 3517 3518 3519 3520 3521 3522 3523 3524 3525 3526 3527 3528 3529 3530 3531 3532 3533 3534 3535 3536 3537 3538 3539 3540 3541 3542 3543 3544 3545 3546 3547
static void update_permission_bitmask(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu)
{
	unsigned bit, byte, pfec;
	u8 map;
	bool fault, x, w, u, wf, uf, ff, smep;

	smep = kvm_read_cr4_bits(vcpu, X86_CR4_SMEP);
	for (byte = 0; byte < ARRAY_SIZE(mmu->permissions); ++byte) {
		pfec = byte << 1;
		map = 0;
		wf = pfec & PFERR_WRITE_MASK;
		uf = pfec & PFERR_USER_MASK;
		ff = pfec & PFERR_FETCH_MASK;
		for (bit = 0; bit < 8; ++bit) {
			x = bit & ACC_EXEC_MASK;
			w = bit & ACC_WRITE_MASK;
			u = bit & ACC_USER_MASK;

			/* Not really needed: !nx will cause pte.nx to fault */
			x |= !mmu->nx;
			/* Allow supervisor writes if !cr0.wp */
			w |= !is_write_protection(vcpu) && !uf;
			/* Disallow supervisor fetches of user code if cr4.smep */
			x &= !(smep && u && !uf);

			fault = (ff && !x) || (uf && !u) || (wf && !w);
			map |= fault << bit;
		}
		mmu->permissions[byte] = map;
	}
}

A
Avi Kivity 已提交
3548 3549 3550 3551 3552 3553 3554 3555 3556 3557 3558 3559 3560 3561 3562 3563 3564 3565
static void update_last_pte_bitmap(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu)
{
	u8 map;
	unsigned level, root_level = mmu->root_level;
	const unsigned ps_set_index = 1 << 2;  /* bit 2 of index: ps */

	if (root_level == PT32E_ROOT_LEVEL)
		--root_level;
	/* PT_PAGE_TABLE_LEVEL always terminates */
	map = 1 | (1 << ps_set_index);
	for (level = PT_DIRECTORY_LEVEL; level <= root_level; ++level) {
		if (level <= PT_PDPE_LEVEL
		    && (mmu->root_level >= PT32E_ROOT_LEVEL || is_pse(vcpu)))
			map |= 1 << (ps_set_index | (level - 1));
	}
	mmu->last_pte_bitmap = map;
}

3566 3567 3568
static int paging64_init_context_common(struct kvm_vcpu *vcpu,
					struct kvm_mmu *context,
					int level)
A
Avi Kivity 已提交
3569
{
3570
	context->nx = is_nx(vcpu);
3571
	context->root_level = level;
3572

3573
	reset_rsvds_bits_mask(vcpu, context);
3574
	update_permission_bitmask(vcpu, context);
A
Avi Kivity 已提交
3575
	update_last_pte_bitmap(vcpu, context);
A
Avi Kivity 已提交
3576 3577 3578 3579 3580

	ASSERT(is_pae(vcpu));
	context->new_cr3 = paging_new_cr3;
	context->page_fault = paging64_page_fault;
	context->gva_to_gpa = paging64_gva_to_gpa;
3581
	context->sync_page = paging64_sync_page;
M
Marcelo Tosatti 已提交
3582
	context->invlpg = paging64_invlpg;
3583
	context->update_pte = paging64_update_pte;
A
Avi Kivity 已提交
3584
	context->free = paging_free;
3585
	context->shadow_root_level = level;
A
Avi Kivity 已提交
3586
	context->root_hpa = INVALID_PAGE;
3587
	context->direct_map = false;
A
Avi Kivity 已提交
3588 3589 3590
	return 0;
}

3591 3592
static int paging64_init_context(struct kvm_vcpu *vcpu,
				 struct kvm_mmu *context)
3593
{
3594
	return paging64_init_context_common(vcpu, context, PT64_ROOT_LEVEL);
3595 3596
}

3597 3598
static int paging32_init_context(struct kvm_vcpu *vcpu,
				 struct kvm_mmu *context)
A
Avi Kivity 已提交
3599
{
3600
	context->nx = false;
3601
	context->root_level = PT32_ROOT_LEVEL;
3602

3603
	reset_rsvds_bits_mask(vcpu, context);
3604
	update_permission_bitmask(vcpu, context);
A
Avi Kivity 已提交
3605
	update_last_pte_bitmap(vcpu, context);
A
Avi Kivity 已提交
3606 3607 3608 3609 3610

	context->new_cr3 = paging_new_cr3;
	context->page_fault = paging32_page_fault;
	context->gva_to_gpa = paging32_gva_to_gpa;
	context->free = paging_free;
3611
	context->sync_page = paging32_sync_page;
M
Marcelo Tosatti 已提交
3612
	context->invlpg = paging32_invlpg;
3613
	context->update_pte = paging32_update_pte;
A
Avi Kivity 已提交
3614
	context->shadow_root_level = PT32E_ROOT_LEVEL;
A
Avi Kivity 已提交
3615
	context->root_hpa = INVALID_PAGE;
3616
	context->direct_map = false;
A
Avi Kivity 已提交
3617 3618 3619
	return 0;
}

3620 3621
static int paging32E_init_context(struct kvm_vcpu *vcpu,
				  struct kvm_mmu *context)
A
Avi Kivity 已提交
3622
{
3623
	return paging64_init_context_common(vcpu, context, PT32E_ROOT_LEVEL);
A
Avi Kivity 已提交
3624 3625
}

3626 3627
static int init_kvm_tdp_mmu(struct kvm_vcpu *vcpu)
{
3628
	struct kvm_mmu *context = vcpu->arch.walk_mmu;
3629

3630
	context->base_role.word = 0;
3631 3632 3633
	context->new_cr3 = nonpaging_new_cr3;
	context->page_fault = tdp_page_fault;
	context->free = nonpaging_free;
3634
	context->sync_page = nonpaging_sync_page;
M
Marcelo Tosatti 已提交
3635
	context->invlpg = nonpaging_invlpg;
3636
	context->update_pte = nonpaging_update_pte;
3637
	context->shadow_root_level = kvm_x86_ops->get_tdp_level();
3638
	context->root_hpa = INVALID_PAGE;
3639
	context->direct_map = true;
3640
	context->set_cr3 = kvm_x86_ops->set_tdp_cr3;
3641
	context->get_cr3 = get_cr3;
3642
	context->get_pdptr = kvm_pdptr_read;
3643
	context->inject_page_fault = kvm_inject_page_fault;
3644 3645

	if (!is_paging(vcpu)) {
3646
		context->nx = false;
3647 3648 3649
		context->gva_to_gpa = nonpaging_gva_to_gpa;
		context->root_level = 0;
	} else if (is_long_mode(vcpu)) {
3650
		context->nx = is_nx(vcpu);
3651
		context->root_level = PT64_ROOT_LEVEL;
3652 3653
		reset_rsvds_bits_mask(vcpu, context);
		context->gva_to_gpa = paging64_gva_to_gpa;
3654
	} else if (is_pae(vcpu)) {
3655
		context->nx = is_nx(vcpu);
3656
		context->root_level = PT32E_ROOT_LEVEL;
3657 3658
		reset_rsvds_bits_mask(vcpu, context);
		context->gva_to_gpa = paging64_gva_to_gpa;
3659
	} else {
3660
		context->nx = false;
3661
		context->root_level = PT32_ROOT_LEVEL;
3662 3663
		reset_rsvds_bits_mask(vcpu, context);
		context->gva_to_gpa = paging32_gva_to_gpa;
3664 3665
	}

3666
	update_permission_bitmask(vcpu, context);
A
Avi Kivity 已提交
3667
	update_last_pte_bitmap(vcpu, context);
3668

3669 3670 3671
	return 0;
}

3672
int kvm_init_shadow_mmu(struct kvm_vcpu *vcpu, struct kvm_mmu *context)
A
Avi Kivity 已提交
3673
{
3674
	int r;
3675
	bool smep = kvm_read_cr4_bits(vcpu, X86_CR4_SMEP);
A
Avi Kivity 已提交
3676
	ASSERT(vcpu);
3677
	ASSERT(!VALID_PAGE(vcpu->arch.mmu.root_hpa));
A
Avi Kivity 已提交
3678 3679

	if (!is_paging(vcpu))
3680
		r = nonpaging_init_context(vcpu, context);
A
Avi Kivity 已提交
3681
	else if (is_long_mode(vcpu))
3682
		r = paging64_init_context(vcpu, context);
A
Avi Kivity 已提交
3683
	else if (is_pae(vcpu))
3684
		r = paging32E_init_context(vcpu, context);
A
Avi Kivity 已提交
3685
	else
3686
		r = paging32_init_context(vcpu, context);
3687

3688
	vcpu->arch.mmu.base_role.nxe = is_nx(vcpu);
3689
	vcpu->arch.mmu.base_role.cr4_pae = !!is_pae(vcpu);
3690
	vcpu->arch.mmu.base_role.cr0_wp  = is_write_protection(vcpu);
3691 3692
	vcpu->arch.mmu.base_role.smep_andnot_wp
		= smep && !is_write_protection(vcpu);
3693 3694 3695 3696 3697 3698 3699

	return r;
}
EXPORT_SYMBOL_GPL(kvm_init_shadow_mmu);

static int init_kvm_softmmu(struct kvm_vcpu *vcpu)
{
3700
	int r = kvm_init_shadow_mmu(vcpu, vcpu->arch.walk_mmu);
3701

3702 3703
	vcpu->arch.walk_mmu->set_cr3           = kvm_x86_ops->set_cr3;
	vcpu->arch.walk_mmu->get_cr3           = get_cr3;
3704
	vcpu->arch.walk_mmu->get_pdptr         = kvm_pdptr_read;
3705
	vcpu->arch.walk_mmu->inject_page_fault = kvm_inject_page_fault;
3706 3707

	return r;
A
Avi Kivity 已提交
3708 3709
}

3710 3711 3712 3713 3714
static int init_kvm_nested_mmu(struct kvm_vcpu *vcpu)
{
	struct kvm_mmu *g_context = &vcpu->arch.nested_mmu;

	g_context->get_cr3           = get_cr3;
3715
	g_context->get_pdptr         = kvm_pdptr_read;
3716 3717 3718 3719 3720 3721 3722 3723 3724
	g_context->inject_page_fault = kvm_inject_page_fault;

	/*
	 * Note that arch.mmu.gva_to_gpa translates l2_gva to l1_gpa. The
	 * translation of l2_gpa to l1_gpa addresses is done using the
	 * arch.nested_mmu.gva_to_gpa function. Basically the gva_to_gpa
	 * functions between mmu and nested_mmu are swapped.
	 */
	if (!is_paging(vcpu)) {
3725
		g_context->nx = false;
3726 3727 3728
		g_context->root_level = 0;
		g_context->gva_to_gpa = nonpaging_gva_to_gpa_nested;
	} else if (is_long_mode(vcpu)) {
3729
		g_context->nx = is_nx(vcpu);
3730
		g_context->root_level = PT64_ROOT_LEVEL;
3731
		reset_rsvds_bits_mask(vcpu, g_context);
3732 3733
		g_context->gva_to_gpa = paging64_gva_to_gpa_nested;
	} else if (is_pae(vcpu)) {
3734
		g_context->nx = is_nx(vcpu);
3735
		g_context->root_level = PT32E_ROOT_LEVEL;
3736
		reset_rsvds_bits_mask(vcpu, g_context);
3737 3738
		g_context->gva_to_gpa = paging64_gva_to_gpa_nested;
	} else {
3739
		g_context->nx = false;
3740
		g_context->root_level = PT32_ROOT_LEVEL;
3741
		reset_rsvds_bits_mask(vcpu, g_context);
3742 3743 3744
		g_context->gva_to_gpa = paging32_gva_to_gpa_nested;
	}

3745
	update_permission_bitmask(vcpu, g_context);
A
Avi Kivity 已提交
3746
	update_last_pte_bitmap(vcpu, g_context);
3747

3748 3749 3750
	return 0;
}

3751 3752
static int init_kvm_mmu(struct kvm_vcpu *vcpu)
{
3753 3754 3755
	if (mmu_is_nested(vcpu))
		return init_kvm_nested_mmu(vcpu);
	else if (tdp_enabled)
3756 3757 3758 3759 3760
		return init_kvm_tdp_mmu(vcpu);
	else
		return init_kvm_softmmu(vcpu);
}

A
Avi Kivity 已提交
3761 3762 3763
static void destroy_kvm_mmu(struct kvm_vcpu *vcpu)
{
	ASSERT(vcpu);
3764 3765
	if (VALID_PAGE(vcpu->arch.mmu.root_hpa))
		/* mmu.free() should set root_hpa = INVALID_PAGE */
3766
		vcpu->arch.mmu.free(vcpu);
A
Avi Kivity 已提交
3767 3768 3769
}

int kvm_mmu_reset_context(struct kvm_vcpu *vcpu)
A
Avi Kivity 已提交
3770 3771
{
	destroy_kvm_mmu(vcpu);
3772
	return init_kvm_mmu(vcpu);
A
Avi Kivity 已提交
3773
}
3774
EXPORT_SYMBOL_GPL(kvm_mmu_reset_context);
A
Avi Kivity 已提交
3775 3776

int kvm_mmu_load(struct kvm_vcpu *vcpu)
A
Avi Kivity 已提交
3777
{
3778 3779
	int r;

3780
	r = mmu_topup_memory_caches(vcpu);
A
Avi Kivity 已提交
3781 3782
	if (r)
		goto out;
3783
	r = mmu_alloc_roots(vcpu);
3784
	kvm_mmu_sync_roots(vcpu);
3785 3786
	if (r)
		goto out;
3787
	/* set_cr3() should ensure TLB has been flushed */
3788
	vcpu->arch.mmu.set_cr3(vcpu, vcpu->arch.mmu.root_hpa);
3789 3790
out:
	return r;
A
Avi Kivity 已提交
3791
}
A
Avi Kivity 已提交
3792 3793 3794 3795 3796 3797
EXPORT_SYMBOL_GPL(kvm_mmu_load);

void kvm_mmu_unload(struct kvm_vcpu *vcpu)
{
	mmu_free_roots(vcpu);
}
3798
EXPORT_SYMBOL_GPL(kvm_mmu_unload);
A
Avi Kivity 已提交
3799

3800
static void mmu_pte_write_new_pte(struct kvm_vcpu *vcpu,
3801 3802
				  struct kvm_mmu_page *sp, u64 *spte,
				  const void *new)
3803
{
3804
	if (sp->role.level != PT_PAGE_TABLE_LEVEL) {
3805 3806
		++vcpu->kvm->stat.mmu_pde_zapped;
		return;
3807
        }
3808

A
Avi Kivity 已提交
3809
	++vcpu->kvm->stat.mmu_pte_updated;
3810
	vcpu->arch.mmu.update_pte(vcpu, sp, spte, new);
3811 3812
}

3813 3814 3815 3816 3817 3818 3819 3820 3821 3822 3823 3824 3825
static bool need_remote_flush(u64 old, u64 new)
{
	if (!is_shadow_present_pte(old))
		return false;
	if (!is_shadow_present_pte(new))
		return true;
	if ((old ^ new) & PT64_BASE_ADDR_MASK)
		return true;
	old ^= PT64_NX_MASK;
	new ^= PT64_NX_MASK;
	return (old & ~new & PT64_PERM_MASK) != 0;
}

3826 3827
static void mmu_pte_write_flush_tlb(struct kvm_vcpu *vcpu, bool zap_page,
				    bool remote_flush, bool local_flush)
3828
{
3829 3830 3831 3832
	if (zap_page)
		return;

	if (remote_flush)
3833
		kvm_flush_remote_tlbs(vcpu->kvm);
3834
	else if (local_flush)
3835 3836 3837
		kvm_mmu_flush_tlb(vcpu);
}

3838 3839
static u64 mmu_pte_write_fetch_gpte(struct kvm_vcpu *vcpu, gpa_t *gpa,
				    const u8 *new, int *bytes)
3840
{
3841 3842
	u64 gentry;
	int r;
3843 3844 3845

	/*
	 * Assume that the pte write on a page table of the same type
3846 3847
	 * as the current vcpu paging mode since we update the sptes only
	 * when they have the same mode.
3848
	 */
3849
	if (is_pae(vcpu) && *bytes == 4) {
3850
		/* Handle a 32-bit guest writing two halves of a 64-bit gpte */
3851 3852
		*gpa &= ~(gpa_t)7;
		*bytes = 8;
3853
		r = kvm_read_guest(vcpu->kvm, *gpa, &gentry, 8);
3854 3855
		if (r)
			gentry = 0;
3856 3857 3858
		new = (const u8 *)&gentry;
	}

3859
	switch (*bytes) {
3860 3861 3862 3863 3864 3865 3866 3867 3868
	case 4:
		gentry = *(const u32 *)new;
		break;
	case 8:
		gentry = *(const u64 *)new;
		break;
	default:
		gentry = 0;
		break;
3869 3870
	}

3871 3872 3873 3874 3875 3876 3877
	return gentry;
}

/*
 * If we're seeing too many writes to a page, it may no longer be a page table,
 * or we may be forking, in which case it is better to unmap the page.
 */
3878
static bool detect_write_flooding(struct kvm_mmu_page *sp)
3879
{
3880 3881 3882 3883
	/*
	 * Skip write-flooding detected for the sp whose level is 1, because
	 * it can become unsync, then the guest page is not write-protected.
	 */
3884
	if (sp->role.level == PT_PAGE_TABLE_LEVEL)
3885
		return false;
3886

3887
	return ++sp->write_flooding_count >= 3;
3888 3889 3890 3891 3892 3893 3894 3895 3896 3897 3898 3899 3900 3901 3902 3903
}

/*
 * Misaligned accesses are too much trouble to fix up; also, they usually
 * indicate a page is not used as a page table.
 */
static bool detect_write_misaligned(struct kvm_mmu_page *sp, gpa_t gpa,
				    int bytes)
{
	unsigned offset, pte_size, misaligned;

	pgprintk("misaligned: gpa %llx bytes %d role %x\n",
		 gpa, bytes, sp->role.word);

	offset = offset_in_page(gpa);
	pte_size = sp->role.cr4_pae ? 8 : 4;
3904 3905 3906 3907 3908 3909 3910 3911

	/*
	 * Sometimes, the OS only writes the last one bytes to update status
	 * bits, for example, in linux, andb instruction is used in clear_bit().
	 */
	if (!(offset & (pte_size - 1)) && bytes == 1)
		return false;

3912 3913 3914 3915 3916 3917 3918 3919 3920 3921 3922 3923 3924 3925 3926 3927 3928 3929 3930 3931 3932 3933 3934 3935 3936 3937 3938 3939 3940 3941 3942 3943 3944 3945 3946 3947 3948 3949 3950 3951 3952 3953 3954 3955 3956 3957
	misaligned = (offset ^ (offset + bytes - 1)) & ~(pte_size - 1);
	misaligned |= bytes < 4;

	return misaligned;
}

static u64 *get_written_sptes(struct kvm_mmu_page *sp, gpa_t gpa, int *nspte)
{
	unsigned page_offset, quadrant;
	u64 *spte;
	int level;

	page_offset = offset_in_page(gpa);
	level = sp->role.level;
	*nspte = 1;
	if (!sp->role.cr4_pae) {
		page_offset <<= 1;	/* 32->64 */
		/*
		 * A 32-bit pde maps 4MB while the shadow pdes map
		 * only 2MB.  So we need to double the offset again
		 * and zap two pdes instead of one.
		 */
		if (level == PT32_ROOT_LEVEL) {
			page_offset &= ~7; /* kill rounding error */
			page_offset <<= 1;
			*nspte = 2;
		}
		quadrant = page_offset >> PAGE_SHIFT;
		page_offset &= ~PAGE_MASK;
		if (quadrant != sp->role.quadrant)
			return NULL;
	}

	spte = &sp->spt[page_offset / sizeof(*spte)];
	return spte;
}

void kvm_mmu_pte_write(struct kvm_vcpu *vcpu, gpa_t gpa,
		       const u8 *new, int bytes)
{
	gfn_t gfn = gpa >> PAGE_SHIFT;
	union kvm_mmu_page_role mask = { .word = 0 };
	struct kvm_mmu_page *sp;
	LIST_HEAD(invalid_list);
	u64 entry, gentry, *spte;
	int npte;
3958
	bool remote_flush, local_flush, zap_page;
3959 3960 3961 3962 3963 3964 3965 3966 3967 3968 3969 3970 3971 3972 3973 3974 3975 3976 3977 3978 3979 3980 3981

	/*
	 * If we don't have indirect shadow pages, it means no page is
	 * write-protected, so we can exit simply.
	 */
	if (!ACCESS_ONCE(vcpu->kvm->arch.indirect_shadow_pages))
		return;

	zap_page = remote_flush = local_flush = false;

	pgprintk("%s: gpa %llx bytes %d\n", __func__, gpa, bytes);

	gentry = mmu_pte_write_fetch_gpte(vcpu, &gpa, new, &bytes);

	/*
	 * No need to care whether allocation memory is successful
	 * or not since pte prefetch is skiped if it does not have
	 * enough objects in the cache.
	 */
	mmu_topup_memory_caches(vcpu);

	spin_lock(&vcpu->kvm->mmu_lock);
	++vcpu->kvm->stat.mmu_pte_write;
3982
	kvm_mmu_audit(vcpu, AUDIT_PRE_PTE_WRITE);
3983

3984
	mask.cr0_wp = mask.cr4_pae = mask.nxe = 1;
3985
	for_each_gfn_indirect_valid_sp(vcpu->kvm, sp, gfn) {
3986
		if (detect_write_misaligned(sp, gpa, bytes) ||
3987
		      detect_write_flooding(sp)) {
3988
			zap_page |= !!kvm_mmu_prepare_zap_page(vcpu->kvm, sp,
3989
						     &invalid_list);
A
Avi Kivity 已提交
3990
			++vcpu->kvm->stat.mmu_flooded;
3991 3992
			continue;
		}
3993 3994 3995 3996 3997

		spte = get_written_sptes(sp, gpa, &npte);
		if (!spte)
			continue;

3998
		local_flush = true;
3999
		while (npte--) {
4000
			entry = *spte;
4001
			mmu_page_zap_pte(vcpu->kvm, sp, spte);
4002 4003
			if (gentry &&
			      !((sp->role.word ^ vcpu->arch.mmu.base_role.word)
4004
			      & mask.word) && rmap_can_add(vcpu))
4005
				mmu_pte_write_new_pte(vcpu, sp, spte, &gentry);
G
Gleb Natapov 已提交
4006
			if (need_remote_flush(entry, *spte))
4007
				remote_flush = true;
4008
			++spte;
4009 4010
		}
	}
4011
	mmu_pte_write_flush_tlb(vcpu, zap_page, remote_flush, local_flush);
4012
	kvm_mmu_commit_zap_page(vcpu->kvm, &invalid_list);
4013
	kvm_mmu_audit(vcpu, AUDIT_POST_PTE_WRITE);
4014
	spin_unlock(&vcpu->kvm->mmu_lock);
4015 4016
}

4017 4018
int kvm_mmu_unprotect_page_virt(struct kvm_vcpu *vcpu, gva_t gva)
{
4019 4020
	gpa_t gpa;
	int r;
4021

4022
	if (vcpu->arch.mmu.direct_map)
4023 4024
		return 0;

4025
	gpa = kvm_mmu_gva_to_gpa_read(vcpu, gva, NULL);
4026 4027

	r = kvm_mmu_unprotect_page(vcpu->kvm, gpa >> PAGE_SHIFT);
4028

4029
	return r;
4030
}
4031
EXPORT_SYMBOL_GPL(kvm_mmu_unprotect_page_virt);
4032

4033
static void make_mmu_pages_available(struct kvm_vcpu *vcpu)
A
Avi Kivity 已提交
4034
{
4035
	LIST_HEAD(invalid_list);
4036

4037 4038 4039
	if (likely(kvm_mmu_available_pages(vcpu->kvm) >= KVM_MIN_FREE_MMU_PAGES))
		return;

4040 4041 4042
	while (kvm_mmu_available_pages(vcpu->kvm) < KVM_REFILL_PAGES) {
		if (!prepare_zap_oldest_mmu_page(vcpu->kvm, &invalid_list))
			break;
A
Avi Kivity 已提交
4043

A
Avi Kivity 已提交
4044
		++vcpu->kvm->stat.mmu_recycled;
A
Avi Kivity 已提交
4045
	}
4046
	kvm_mmu_commit_zap_page(vcpu->kvm, &invalid_list);
A
Avi Kivity 已提交
4047 4048
}

4049 4050 4051 4052 4053 4054 4055 4056
static bool is_mmio_page_fault(struct kvm_vcpu *vcpu, gva_t addr)
{
	if (vcpu->arch.mmu.direct_map || mmu_is_nested(vcpu))
		return vcpu_match_mmio_gpa(vcpu, addr);

	return vcpu_match_mmio_gva(vcpu, addr);
}

4057 4058
int kvm_mmu_page_fault(struct kvm_vcpu *vcpu, gva_t cr2, u32 error_code,
		       void *insn, int insn_len)
4059
{
4060
	int r, emulation_type = EMULTYPE_RETRY;
4061 4062
	enum emulation_result er;

G
Gleb Natapov 已提交
4063
	r = vcpu->arch.mmu.page_fault(vcpu, cr2, error_code, false);
4064 4065 4066 4067 4068 4069 4070 4071
	if (r < 0)
		goto out;

	if (!r) {
		r = 1;
		goto out;
	}

4072 4073 4074 4075
	if (is_mmio_page_fault(vcpu, cr2))
		emulation_type = 0;

	er = x86_emulate_instruction(vcpu, cr2, emulation_type, insn, insn_len);
4076 4077 4078 4079 4080 4081

	switch (er) {
	case EMULATE_DONE:
		return 1;
	case EMULATE_DO_MMIO:
		++vcpu->stat.mmio_exits;
4082
		/* fall through */
4083
	case EMULATE_FAIL:
4084
		return 0;
4085 4086 4087 4088 4089 4090 4091 4092
	default:
		BUG();
	}
out:
	return r;
}
EXPORT_SYMBOL_GPL(kvm_mmu_page_fault);

M
Marcelo Tosatti 已提交
4093 4094 4095 4096 4097 4098 4099 4100
void kvm_mmu_invlpg(struct kvm_vcpu *vcpu, gva_t gva)
{
	vcpu->arch.mmu.invlpg(vcpu, gva);
	kvm_mmu_flush_tlb(vcpu);
	++vcpu->stat.invlpg;
}
EXPORT_SYMBOL_GPL(kvm_mmu_invlpg);

4101 4102 4103 4104 4105 4106
void kvm_enable_tdp(void)
{
	tdp_enabled = true;
}
EXPORT_SYMBOL_GPL(kvm_enable_tdp);

4107 4108 4109 4110 4111 4112
void kvm_disable_tdp(void)
{
	tdp_enabled = false;
}
EXPORT_SYMBOL_GPL(kvm_disable_tdp);

A
Avi Kivity 已提交
4113 4114
static void free_mmu_pages(struct kvm_vcpu *vcpu)
{
4115
	free_page((unsigned long)vcpu->arch.mmu.pae_root);
4116 4117
	if (vcpu->arch.mmu.lm_root != NULL)
		free_page((unsigned long)vcpu->arch.mmu.lm_root);
A
Avi Kivity 已提交
4118 4119 4120 4121
}

static int alloc_mmu_pages(struct kvm_vcpu *vcpu)
{
4122
	struct page *page;
A
Avi Kivity 已提交
4123 4124 4125 4126
	int i;

	ASSERT(vcpu);

4127 4128 4129 4130 4131 4132 4133
	/*
	 * When emulating 32-bit mode, cr3 is only 32 bits even on x86_64.
	 * Therefore we need to allocate shadow page tables in the first
	 * 4GB of memory, which happens to fit the DMA32 zone.
	 */
	page = alloc_page(GFP_KERNEL | __GFP_DMA32);
	if (!page)
4134 4135
		return -ENOMEM;

4136
	vcpu->arch.mmu.pae_root = page_address(page);
4137
	for (i = 0; i < 4; ++i)
4138
		vcpu->arch.mmu.pae_root[i] = INVALID_PAGE;
4139

A
Avi Kivity 已提交
4140 4141 4142
	return 0;
}

4143
int kvm_mmu_create(struct kvm_vcpu *vcpu)
A
Avi Kivity 已提交
4144 4145
{
	ASSERT(vcpu);
4146 4147 4148 4149 4150

	vcpu->arch.walk_mmu = &vcpu->arch.mmu;
	vcpu->arch.mmu.root_hpa = INVALID_PAGE;
	vcpu->arch.mmu.translate_gpa = translate_gpa;
	vcpu->arch.nested_mmu.translate_gpa = translate_nested_gpa;
A
Avi Kivity 已提交
4151

4152 4153
	return alloc_mmu_pages(vcpu);
}
A
Avi Kivity 已提交
4154

4155 4156 4157
int kvm_mmu_setup(struct kvm_vcpu *vcpu)
{
	ASSERT(vcpu);
4158
	ASSERT(!VALID_PAGE(vcpu->arch.mmu.root_hpa));
4159

4160
	return init_kvm_mmu(vcpu);
A
Avi Kivity 已提交
4161 4162
}

4163
void kvm_mmu_slot_remove_write_access(struct kvm *kvm, int slot)
A
Avi Kivity 已提交
4164
{
4165 4166 4167
	struct kvm_memory_slot *memslot;
	gfn_t last_gfn;
	int i;
A
Avi Kivity 已提交
4168

4169 4170
	memslot = id_to_memslot(kvm->memslots, slot);
	last_gfn = memslot->base_gfn + memslot->npages - 1;
A
Avi Kivity 已提交
4171

4172 4173
	spin_lock(&kvm->mmu_lock);

4174 4175 4176 4177
	for (i = PT_PAGE_TABLE_LEVEL;
	     i < PT_PAGE_TABLE_LEVEL + KVM_NR_PAGE_SIZES; ++i) {
		unsigned long *rmapp;
		unsigned long last_index, index;
A
Avi Kivity 已提交
4178

4179 4180
		rmapp = memslot->arch.rmap[i - PT_PAGE_TABLE_LEVEL];
		last_index = gfn_to_index(last_gfn, memslot->base_gfn, i);
4181

4182 4183 4184
		for (index = 0; index <= last_index; ++index, ++rmapp) {
			if (*rmapp)
				__rmap_write_protect(kvm, rmapp, false);
4185 4186 4187 4188 4189

			if (need_resched() || spin_needbreak(&kvm->mmu_lock)) {
				kvm_flush_remote_tlbs(kvm);
				cond_resched_lock(&kvm->mmu_lock);
			}
4190
		}
A
Avi Kivity 已提交
4191
	}
4192

4193
	kvm_flush_remote_tlbs(kvm);
4194
	spin_unlock(&kvm->mmu_lock);
A
Avi Kivity 已提交
4195
}
4196

4197 4198 4199 4200 4201 4202 4203 4204 4205 4206 4207 4208 4209 4210 4211 4212 4213 4214 4215 4216 4217 4218 4219 4220 4221 4222 4223 4224 4225 4226 4227 4228 4229 4230 4231 4232 4233 4234 4235 4236 4237 4238 4239 4240 4241 4242 4243 4244 4245 4246 4247 4248 4249 4250 4251 4252 4253 4254 4255 4256 4257 4258 4259 4260 4261 4262 4263 4264 4265 4266
static void kvm_zap_obsolete_pages(struct kvm *kvm)
{
	struct kvm_mmu_page *sp, *node;
	LIST_HEAD(invalid_list);

restart:
	list_for_each_entry_safe_reverse(sp, node,
	      &kvm->arch.active_mmu_pages, link) {
		/*
		 * No obsolete page exists before new created page since
		 * active_mmu_pages is the FIFO list.
		 */
		if (!is_obsolete_sp(kvm, sp))
			break;

		/*
		 * Do not repeatedly zap a root page to avoid unnecessary
		 * KVM_REQ_MMU_RELOAD, otherwise we may not be able to
		 * progress:
		 *    vcpu 0                        vcpu 1
		 *                         call vcpu_enter_guest():
		 *                            1): handle KVM_REQ_MMU_RELOAD
		 *                                and require mmu-lock to
		 *                                load mmu
		 * repeat:
		 *    1): zap root page and
		 *        send KVM_REQ_MMU_RELOAD
		 *
		 *    2): if (cond_resched_lock(mmu-lock))
		 *
		 *                            2): hold mmu-lock and load mmu
		 *
		 *                            3): see KVM_REQ_MMU_RELOAD bit
		 *                                on vcpu->requests is set
		 *                                then return 1 to call
		 *                                vcpu_enter_guest() again.
		 *            goto repeat;
		 *
		 * Since we are reversely walking the list and the invalid
		 * list will be moved to the head, skip the invalid page
		 * can help us to avoid the infinity list walking.
		 */
		if (sp->role.invalid)
			continue;

		if (need_resched() || spin_needbreak(&kvm->mmu_lock)) {
			kvm_mmu_commit_zap_page(kvm, &invalid_list);
			cond_resched_lock(&kvm->mmu_lock);
			goto restart;
		}

		if (kvm_mmu_prepare_zap_page(kvm, sp, &invalid_list))
			goto restart;
	}

	kvm_mmu_commit_zap_page(kvm, &invalid_list);
}

/*
 * Fast invalidate all shadow pages and use lock-break technique
 * to zap obsolete pages.
 *
 * It's required when memslot is being deleted or VM is being
 * destroyed, in these cases, we should ensure that KVM MMU does
 * not use any resource of the being-deleted slot or all slots
 * after calling the function.
 */
void kvm_mmu_invalidate_zap_all_pages(struct kvm *kvm)
{
	spin_lock(&kvm->mmu_lock);
4267
	trace_kvm_mmu_invalidate_zap_all_pages(kvm);
4268 4269 4270 4271 4272 4273
	kvm->arch.mmu_valid_gen++;

	kvm_zap_obsolete_pages(kvm);
	spin_unlock(&kvm->mmu_lock);
}

4274 4275 4276 4277 4278 4279 4280 4281 4282 4283 4284 4285 4286 4287 4288 4289 4290 4291
void kvm_mmu_zap_mmio_sptes(struct kvm *kvm)
{
	struct kvm_mmu_page *sp, *node;
	LIST_HEAD(invalid_list);

	spin_lock(&kvm->mmu_lock);
restart:
	list_for_each_entry_safe(sp, node, &kvm->arch.active_mmu_pages, link) {
		if (!sp->mmio_cached)
			continue;
		if (kvm_mmu_prepare_zap_page(kvm, sp, &invalid_list))
			goto restart;
	}

	kvm_mmu_commit_zap_page(kvm, &invalid_list);
	spin_unlock(&kvm->mmu_lock);
}

4292
static int mmu_shrink(struct shrinker *shrink, struct shrink_control *sc)
4293 4294
{
	struct kvm *kvm;
4295
	int nr_to_scan = sc->nr_to_scan;
4296 4297 4298

	if (nr_to_scan == 0)
		goto out;
4299

4300
	raw_spin_lock(&kvm_lock);
4301 4302

	list_for_each_entry(kvm, &vm_list, vm_list) {
4303
		int idx;
4304
		LIST_HEAD(invalid_list);
4305

4306 4307 4308 4309 4310 4311 4312 4313
		/*
		 * Never scan more than sc->nr_to_scan VM instances.
		 * Will not hit this condition practically since we do not try
		 * to shrink more than one VM and it is very unlikely to see
		 * !n_used_mmu_pages so many times.
		 */
		if (!nr_to_scan--)
			break;
4314 4315 4316 4317 4318 4319
		/*
		 * n_used_mmu_pages is accessed without holding kvm->mmu_lock
		 * here. We may skip a VM instance errorneosly, but we do not
		 * want to shrink a VM that only started to populate its MMU
		 * anyway.
		 */
4320
		if (!kvm->arch.n_used_mmu_pages)
4321 4322
			continue;

4323
		idx = srcu_read_lock(&kvm->srcu);
4324 4325
		spin_lock(&kvm->mmu_lock);

4326
		prepare_zap_oldest_mmu_page(kvm, &invalid_list);
4327
		kvm_mmu_commit_zap_page(kvm, &invalid_list);
4328

4329
		spin_unlock(&kvm->mmu_lock);
4330
		srcu_read_unlock(&kvm->srcu, idx);
4331 4332 4333

		list_move_tail(&kvm->vm_list, &vm_list);
		break;
4334 4335
	}

4336
	raw_spin_unlock(&kvm_lock);
4337

4338 4339
out:
	return percpu_counter_read_positive(&kvm_total_used_mmu_pages);
4340 4341 4342 4343 4344 4345 4346
}

static struct shrinker mmu_shrinker = {
	.shrink = mmu_shrink,
	.seeks = DEFAULT_SEEKS * 10,
};

I
Ingo Molnar 已提交
4347
static void mmu_destroy_caches(void)
4348
{
4349 4350
	if (pte_list_desc_cache)
		kmem_cache_destroy(pte_list_desc_cache);
4351 4352
	if (mmu_page_header_cache)
		kmem_cache_destroy(mmu_page_header_cache);
4353 4354 4355 4356
}

int kvm_mmu_module_init(void)
{
4357 4358
	pte_list_desc_cache = kmem_cache_create("pte_list_desc",
					    sizeof(struct pte_list_desc),
4359
					    0, 0, NULL);
4360
	if (!pte_list_desc_cache)
4361 4362
		goto nomem;

4363 4364
	mmu_page_header_cache = kmem_cache_create("kvm_mmu_page_header",
						  sizeof(struct kvm_mmu_page),
4365
						  0, 0, NULL);
4366 4367 4368
	if (!mmu_page_header_cache)
		goto nomem;

4369 4370 4371
	if (percpu_counter_init(&kvm_total_used_mmu_pages, 0))
		goto nomem;

4372 4373
	register_shrinker(&mmu_shrinker);

4374 4375 4376
	return 0;

nomem:
4377
	mmu_destroy_caches();
4378 4379 4380
	return -ENOMEM;
}

4381 4382 4383 4384 4385 4386 4387
/*
 * Caculate mmu pages needed for kvm.
 */
unsigned int kvm_mmu_calculate_mmu_pages(struct kvm *kvm)
{
	unsigned int nr_mmu_pages;
	unsigned int  nr_pages = 0;
4388
	struct kvm_memslots *slots;
4389
	struct kvm_memory_slot *memslot;
4390

4391 4392
	slots = kvm_memslots(kvm);

4393 4394
	kvm_for_each_memslot(memslot, slots)
		nr_pages += memslot->npages;
4395 4396 4397 4398 4399 4400 4401 4402

	nr_mmu_pages = nr_pages * KVM_PERMILLE_MMU_PAGES / 1000;
	nr_mmu_pages = max(nr_mmu_pages,
			(unsigned int) KVM_MIN_ALLOC_MMU_PAGES);

	return nr_mmu_pages;
}

4403 4404 4405
int kvm_mmu_get_spte_hierarchy(struct kvm_vcpu *vcpu, u64 addr, u64 sptes[4])
{
	struct kvm_shadow_walk_iterator iterator;
4406
	u64 spte;
4407 4408
	int nr_sptes = 0;

4409 4410 4411
	walk_shadow_page_lockless_begin(vcpu);
	for_each_shadow_entry_lockless(vcpu, addr, iterator, spte) {
		sptes[iterator.level-1] = spte;
4412
		nr_sptes++;
4413
		if (!is_shadow_present_pte(spte))
4414 4415
			break;
	}
4416
	walk_shadow_page_lockless_end(vcpu);
4417 4418 4419 4420 4421

	return nr_sptes;
}
EXPORT_SYMBOL_GPL(kvm_mmu_get_spte_hierarchy);

4422 4423 4424 4425 4426 4427 4428
void kvm_mmu_destroy(struct kvm_vcpu *vcpu)
{
	ASSERT(vcpu);

	destroy_kvm_mmu(vcpu);
	free_mmu_pages(vcpu);
	mmu_free_memory_caches(vcpu);
4429 4430 4431 4432 4433 4434 4435
}

void kvm_mmu_module_exit(void)
{
	mmu_destroy_caches();
	percpu_counter_destroy(&kvm_total_used_mmu_pages);
	unregister_shrinker(&mmu_shrinker);
4436 4437
	mmu_audit_disable();
}