gmap.c 58.7 KB
Newer Older
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23
/*
 *  KVM guest address space mapping code
 *
 *    Copyright IBM Corp. 2007, 2016
 *    Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>
 */

#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/swap.h>
#include <linux/smp.h>
#include <linux/spinlock.h>
#include <linux/slab.h>
#include <linux/swapops.h>
#include <linux/ksm.h>
#include <linux/mman.h>

#include <asm/pgtable.h>
#include <asm/pgalloc.h>
#include <asm/gmap.h>
#include <asm/tlb.h>

/**
24
 * gmap_alloc - allocate and initialize a guest address space
25
 * @mm: pointer to the parent mm_struct
26
 * @limit: maximum address of the gmap address space
27 28 29
 *
 * Returns a guest address space structure.
 */
30
static struct gmap *gmap_alloc(unsigned long limit)
31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57
{
	struct gmap *gmap;
	struct page *page;
	unsigned long *table;
	unsigned long etype, atype;

	if (limit < (1UL << 31)) {
		limit = (1UL << 31) - 1;
		atype = _ASCE_TYPE_SEGMENT;
		etype = _SEGMENT_ENTRY_EMPTY;
	} else if (limit < (1UL << 42)) {
		limit = (1UL << 42) - 1;
		atype = _ASCE_TYPE_REGION3;
		etype = _REGION3_ENTRY_EMPTY;
	} else if (limit < (1UL << 53)) {
		limit = (1UL << 53) - 1;
		atype = _ASCE_TYPE_REGION2;
		etype = _REGION2_ENTRY_EMPTY;
	} else {
		limit = -1UL;
		atype = _ASCE_TYPE_REGION1;
		etype = _REGION1_ENTRY_EMPTY;
	}
	gmap = kzalloc(sizeof(struct gmap), GFP_KERNEL);
	if (!gmap)
		goto out;
	INIT_LIST_HEAD(&gmap->crst_list);
58 59
	INIT_LIST_HEAD(&gmap->children);
	INIT_LIST_HEAD(&gmap->pt_list);
60 61
	INIT_RADIX_TREE(&gmap->guest_to_host, GFP_KERNEL);
	INIT_RADIX_TREE(&gmap->host_to_guest, GFP_ATOMIC);
62
	INIT_RADIX_TREE(&gmap->host_to_rmap, GFP_ATOMIC);
63
	spin_lock_init(&gmap->guest_table_lock);
64
	spin_lock_init(&gmap->shadow_lock);
65
	atomic_set(&gmap->ref_count, 1);
66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83
	page = alloc_pages(GFP_KERNEL, 2);
	if (!page)
		goto out_free;
	page->index = 0;
	list_add(&page->lru, &gmap->crst_list);
	table = (unsigned long *) page_to_phys(page);
	crst_table_init(table, etype);
	gmap->table = table;
	gmap->asce = atype | _ASCE_TABLE_LENGTH |
		_ASCE_USER_BITS | __pa(table);
	gmap->asce_end = limit;
	return gmap;

out_free:
	kfree(gmap);
out:
	return NULL;
}
84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105

/**
 * gmap_create - create a guest address space
 * @mm: pointer to the parent mm_struct
 * @limit: maximum size of the gmap address space
 *
 * Returns a guest address space structure.
 */
struct gmap *gmap_create(struct mm_struct *mm, unsigned long limit)
{
	struct gmap *gmap;

	gmap = gmap_alloc(limit);
	if (!gmap)
		return NULL;
	gmap->mm = mm;
	spin_lock(&mm->context.gmap_lock);
	list_add_rcu(&gmap->list, &mm->context.gmap_list);
	spin_unlock(&mm->context.gmap_lock);
	return gmap;
}
EXPORT_SYMBOL_GPL(gmap_create);
106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138

static void gmap_flush_tlb(struct gmap *gmap)
{
	if (MACHINE_HAS_IDTE)
		__tlb_flush_asce(gmap->mm, gmap->asce);
	else
		__tlb_flush_global();
}

static void gmap_radix_tree_free(struct radix_tree_root *root)
{
	struct radix_tree_iter iter;
	unsigned long indices[16];
	unsigned long index;
	void **slot;
	int i, nr;

	/* A radix tree is freed by deleting all of its entries */
	index = 0;
	do {
		nr = 0;
		radix_tree_for_each_slot(slot, root, &iter, index) {
			indices[nr] = iter.index;
			if (++nr == 16)
				break;
		}
		for (i = 0; i < nr; i++) {
			index = indices[i];
			radix_tree_delete(root, index);
		}
	} while (nr > 0);
}

139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165
static void gmap_rmap_radix_tree_free(struct radix_tree_root *root)
{
	struct gmap_rmap *rmap, *rnext, *head;
	struct radix_tree_iter iter;
	unsigned long indices[16];
	unsigned long index;
	void **slot;
	int i, nr;

	/* A radix tree is freed by deleting all of its entries */
	index = 0;
	do {
		nr = 0;
		radix_tree_for_each_slot(slot, root, &iter, index) {
			indices[nr] = iter.index;
			if (++nr == 16)
				break;
		}
		for (i = 0; i < nr; i++) {
			index = indices[i];
			head = radix_tree_delete(root, index);
			gmap_for_each_rmap_safe(rmap, rnext, head)
				kfree(rmap);
		}
	} while (nr > 0);
}

166 167 168
/**
 * gmap_free - free a guest address space
 * @gmap: pointer to the guest address space structure
169 170
 *
 * No locks required. There are no references to this gmap anymore.
171
 */
172
static void gmap_free(struct gmap *gmap)
173 174 175
{
	struct page *page, *next;

176 177 178
	/* Flush tlb of all gmaps (if not already done for shadows) */
	if (!(gmap_is_shadow(gmap) && gmap->removed))
		gmap_flush_tlb(gmap);
179 180 181 182 183
	/* Free all segment & region tables. */
	list_for_each_entry_safe(page, next, &gmap->crst_list, lru)
		__free_pages(page, 2);
	gmap_radix_tree_free(&gmap->guest_to_host);
	gmap_radix_tree_free(&gmap->host_to_guest);
184 185 186 187 188 189 190 191 192 193 194

	/* Free additional data for a shadow gmap */
	if (gmap_is_shadow(gmap)) {
		/* Free all page tables. */
		list_for_each_entry_safe(page, next, &gmap->pt_list, lru)
			page_table_free_pgste(page);
		gmap_rmap_radix_tree_free(&gmap->host_to_rmap);
		/* Release reference to the parent */
		gmap_put(gmap->parent);
	}

195 196
	kfree(gmap);
}
197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229

/**
 * gmap_get - increase reference counter for guest address space
 * @gmap: pointer to the guest address space structure
 *
 * Returns the gmap pointer
 */
struct gmap *gmap_get(struct gmap *gmap)
{
	atomic_inc(&gmap->ref_count);
	return gmap;
}
EXPORT_SYMBOL_GPL(gmap_get);

/**
 * gmap_put - decrease reference counter for guest address space
 * @gmap: pointer to the guest address space structure
 *
 * If the reference counter reaches zero the guest address space is freed.
 */
void gmap_put(struct gmap *gmap)
{
	if (atomic_dec_return(&gmap->ref_count) == 0)
		gmap_free(gmap);
}
EXPORT_SYMBOL_GPL(gmap_put);

/**
 * gmap_remove - remove a guest address space but do not free it yet
 * @gmap: pointer to the guest address space structure
 */
void gmap_remove(struct gmap *gmap)
{
230 231 232 233 234 235 236 237 238 239 240
	struct gmap *sg, *next;

	/* Remove all shadow gmaps linked to this gmap */
	if (!list_empty(&gmap->children)) {
		spin_lock(&gmap->shadow_lock);
		list_for_each_entry_safe(sg, next, &gmap->children, list) {
			list_del(&sg->list);
			gmap_put(sg);
		}
		spin_unlock(&gmap->shadow_lock);
	}
241 242 243 244 245 246 247 248 249
	/* Remove gmap from the pre-mm list */
	spin_lock(&gmap->mm->context.gmap_lock);
	list_del_rcu(&gmap->list);
	spin_unlock(&gmap->mm->context.gmap_lock);
	synchronize_rcu();
	/* Put reference */
	gmap_put(gmap);
}
EXPORT_SYMBOL_GPL(gmap_remove);
250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285

/**
 * gmap_enable - switch primary space to the guest address space
 * @gmap: pointer to the guest address space structure
 */
void gmap_enable(struct gmap *gmap)
{
	S390_lowcore.gmap = (unsigned long) gmap;
}
EXPORT_SYMBOL_GPL(gmap_enable);

/**
 * gmap_disable - switch back to the standard primary address space
 * @gmap: pointer to the guest address space structure
 */
void gmap_disable(struct gmap *gmap)
{
	S390_lowcore.gmap = 0UL;
}
EXPORT_SYMBOL_GPL(gmap_disable);

/*
 * gmap_alloc_table is assumed to be called with mmap_sem held
 */
static int gmap_alloc_table(struct gmap *gmap, unsigned long *table,
			    unsigned long init, unsigned long gaddr)
{
	struct page *page;
	unsigned long *new;

	/* since we dont free the gmap table until gmap_free we can unlock */
	page = alloc_pages(GFP_KERNEL, 2);
	if (!page)
		return -ENOMEM;
	new = (unsigned long *) page_to_phys(page);
	crst_table_init(new, init);
286
	spin_lock(&gmap->guest_table_lock);
287 288 289 290 291 292 293
	if (*table & _REGION_ENTRY_INVALID) {
		list_add(&page->lru, &gmap->crst_list);
		*table = (unsigned long) new | _REGION_ENTRY_LENGTH |
			(*table & _REGION_ENTRY_TYPE_MASK);
		page->index = gaddr;
		page = NULL;
	}
294
	spin_unlock(&gmap->guest_table_lock);
295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329
	if (page)
		__free_pages(page, 2);
	return 0;
}

/**
 * __gmap_segment_gaddr - find virtual address from segment pointer
 * @entry: pointer to a segment table entry in the guest address space
 *
 * Returns the virtual address in the guest address space for the segment
 */
static unsigned long __gmap_segment_gaddr(unsigned long *entry)
{
	struct page *page;
	unsigned long offset, mask;

	offset = (unsigned long) entry / sizeof(unsigned long);
	offset = (offset & (PTRS_PER_PMD - 1)) * PMD_SIZE;
	mask = ~(PTRS_PER_PMD * sizeof(pmd_t) - 1);
	page = virt_to_page((void *)((unsigned long) entry & mask));
	return page->index + offset;
}

/**
 * __gmap_unlink_by_vmaddr - unlink a single segment via a host address
 * @gmap: pointer to the guest address space structure
 * @vmaddr: address in the host process address space
 *
 * Returns 1 if a TLB flush is required
 */
static int __gmap_unlink_by_vmaddr(struct gmap *gmap, unsigned long vmaddr)
{
	unsigned long *entry;
	int flush = 0;

330
	BUG_ON(gmap_is_shadow(gmap));
331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369
	spin_lock(&gmap->guest_table_lock);
	entry = radix_tree_delete(&gmap->host_to_guest, vmaddr >> PMD_SHIFT);
	if (entry) {
		flush = (*entry != _SEGMENT_ENTRY_INVALID);
		*entry = _SEGMENT_ENTRY_INVALID;
	}
	spin_unlock(&gmap->guest_table_lock);
	return flush;
}

/**
 * __gmap_unmap_by_gaddr - unmap a single segment via a guest address
 * @gmap: pointer to the guest address space structure
 * @gaddr: address in the guest address space
 *
 * Returns 1 if a TLB flush is required
 */
static int __gmap_unmap_by_gaddr(struct gmap *gmap, unsigned long gaddr)
{
	unsigned long vmaddr;

	vmaddr = (unsigned long) radix_tree_delete(&gmap->guest_to_host,
						   gaddr >> PMD_SHIFT);
	return vmaddr ? __gmap_unlink_by_vmaddr(gmap, vmaddr) : 0;
}

/**
 * gmap_unmap_segment - unmap segment from the guest address space
 * @gmap: pointer to the guest address space structure
 * @to: address in the guest address space
 * @len: length of the memory area to unmap
 *
 * Returns 0 if the unmap succeeded, -EINVAL if not.
 */
int gmap_unmap_segment(struct gmap *gmap, unsigned long to, unsigned long len)
{
	unsigned long off;
	int flush;

370
	BUG_ON(gmap_is_shadow(gmap));
371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401
	if ((to | len) & (PMD_SIZE - 1))
		return -EINVAL;
	if (len == 0 || to + len < to)
		return -EINVAL;

	flush = 0;
	down_write(&gmap->mm->mmap_sem);
	for (off = 0; off < len; off += PMD_SIZE)
		flush |= __gmap_unmap_by_gaddr(gmap, to + off);
	up_write(&gmap->mm->mmap_sem);
	if (flush)
		gmap_flush_tlb(gmap);
	return 0;
}
EXPORT_SYMBOL_GPL(gmap_unmap_segment);

/**
 * gmap_map_segment - map a segment to the guest address space
 * @gmap: pointer to the guest address space structure
 * @from: source address in the parent address space
 * @to: target address in the guest address space
 * @len: length of the memory area to map
 *
 * Returns 0 if the mmap succeeded, -EINVAL or -ENOMEM if not.
 */
int gmap_map_segment(struct gmap *gmap, unsigned long from,
		     unsigned long to, unsigned long len)
{
	unsigned long off;
	int flush;

402
	BUG_ON(gmap_is_shadow(gmap));
403 404 405
	if ((from | to | len) & (PMD_SIZE - 1))
		return -EINVAL;
	if (len == 0 || from + len < from || to + len < to ||
406
	    from + len - 1 > TASK_MAX_SIZE || to + len - 1 > gmap->asce_end)
407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439
		return -EINVAL;

	flush = 0;
	down_write(&gmap->mm->mmap_sem);
	for (off = 0; off < len; off += PMD_SIZE) {
		/* Remove old translation */
		flush |= __gmap_unmap_by_gaddr(gmap, to + off);
		/* Store new translation */
		if (radix_tree_insert(&gmap->guest_to_host,
				      (to + off) >> PMD_SHIFT,
				      (void *) from + off))
			break;
	}
	up_write(&gmap->mm->mmap_sem);
	if (flush)
		gmap_flush_tlb(gmap);
	if (off >= len)
		return 0;
	gmap_unmap_segment(gmap, to, len);
	return -ENOMEM;
}
EXPORT_SYMBOL_GPL(gmap_map_segment);

/**
 * __gmap_translate - translate a guest address to a user space address
 * @gmap: pointer to guest mapping meta data structure
 * @gaddr: guest address
 *
 * Returns user space address which corresponds to the guest address or
 * -EFAULT if no such mapping exists.
 * This function does not establish potentially missing page table entries.
 * The mmap_sem of the mm that belongs to the address space must be held
 * when this function gets called.
440 441
 *
 * Note: Can also be called for shadow gmaps.
442 443 444 445 446 447 448
 */
unsigned long __gmap_translate(struct gmap *gmap, unsigned long gaddr)
{
	unsigned long vmaddr;

	vmaddr = (unsigned long)
		radix_tree_lookup(&gmap->guest_to_host, gaddr >> PMD_SHIFT);
449
	/* Note: guest_to_host is empty for a shadow gmap */
450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485
	return vmaddr ? (vmaddr | (gaddr & ~PMD_MASK)) : -EFAULT;
}
EXPORT_SYMBOL_GPL(__gmap_translate);

/**
 * gmap_translate - translate a guest address to a user space address
 * @gmap: pointer to guest mapping meta data structure
 * @gaddr: guest address
 *
 * Returns user space address which corresponds to the guest address or
 * -EFAULT if no such mapping exists.
 * This function does not establish potentially missing page table entries.
 */
unsigned long gmap_translate(struct gmap *gmap, unsigned long gaddr)
{
	unsigned long rc;

	down_read(&gmap->mm->mmap_sem);
	rc = __gmap_translate(gmap, gaddr);
	up_read(&gmap->mm->mmap_sem);
	return rc;
}
EXPORT_SYMBOL_GPL(gmap_translate);

/**
 * gmap_unlink - disconnect a page table from the gmap shadow tables
 * @gmap: pointer to guest mapping meta data structure
 * @table: pointer to the host page table
 * @vmaddr: vm address associated with the host page table
 */
void gmap_unlink(struct mm_struct *mm, unsigned long *table,
		 unsigned long vmaddr)
{
	struct gmap *gmap;
	int flush;

486 487
	rcu_read_lock();
	list_for_each_entry_rcu(gmap, &mm->context.gmap_list, list) {
488 489 490 491
		flush = __gmap_unlink_by_vmaddr(gmap, vmaddr);
		if (flush)
			gmap_flush_tlb(gmap);
	}
492
	rcu_read_unlock();
493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515
}

/**
 * gmap_link - set up shadow page tables to connect a host to a guest address
 * @gmap: pointer to guest mapping meta data structure
 * @gaddr: guest address
 * @vmaddr: vm address
 *
 * Returns 0 on success, -ENOMEM for out of memory conditions, and -EFAULT
 * if the vm address is already mapped to a different guest segment.
 * The mmap_sem of the mm that belongs to the address space must be held
 * when this function gets called.
 */
int __gmap_link(struct gmap *gmap, unsigned long gaddr, unsigned long vmaddr)
{
	struct mm_struct *mm;
	unsigned long *table;
	spinlock_t *ptl;
	pgd_t *pgd;
	pud_t *pud;
	pmd_t *pmd;
	int rc;

516
	BUG_ON(gmap_is_shadow(gmap));
517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668
	/* Create higher level tables in the gmap page table */
	table = gmap->table;
	if ((gmap->asce & _ASCE_TYPE_MASK) >= _ASCE_TYPE_REGION1) {
		table += (gaddr >> 53) & 0x7ff;
		if ((*table & _REGION_ENTRY_INVALID) &&
		    gmap_alloc_table(gmap, table, _REGION2_ENTRY_EMPTY,
				     gaddr & 0xffe0000000000000UL))
			return -ENOMEM;
		table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN);
	}
	if ((gmap->asce & _ASCE_TYPE_MASK) >= _ASCE_TYPE_REGION2) {
		table += (gaddr >> 42) & 0x7ff;
		if ((*table & _REGION_ENTRY_INVALID) &&
		    gmap_alloc_table(gmap, table, _REGION3_ENTRY_EMPTY,
				     gaddr & 0xfffffc0000000000UL))
			return -ENOMEM;
		table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN);
	}
	if ((gmap->asce & _ASCE_TYPE_MASK) >= _ASCE_TYPE_REGION3) {
		table += (gaddr >> 31) & 0x7ff;
		if ((*table & _REGION_ENTRY_INVALID) &&
		    gmap_alloc_table(gmap, table, _SEGMENT_ENTRY_EMPTY,
				     gaddr & 0xffffffff80000000UL))
			return -ENOMEM;
		table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN);
	}
	table += (gaddr >> 20) & 0x7ff;
	/* Walk the parent mm page table */
	mm = gmap->mm;
	pgd = pgd_offset(mm, vmaddr);
	VM_BUG_ON(pgd_none(*pgd));
	pud = pud_offset(pgd, vmaddr);
	VM_BUG_ON(pud_none(*pud));
	pmd = pmd_offset(pud, vmaddr);
	VM_BUG_ON(pmd_none(*pmd));
	/* large pmds cannot yet be handled */
	if (pmd_large(*pmd))
		return -EFAULT;
	/* Link gmap segment table entry location to page table. */
	rc = radix_tree_preload(GFP_KERNEL);
	if (rc)
		return rc;
	ptl = pmd_lock(mm, pmd);
	spin_lock(&gmap->guest_table_lock);
	if (*table == _SEGMENT_ENTRY_INVALID) {
		rc = radix_tree_insert(&gmap->host_to_guest,
				       vmaddr >> PMD_SHIFT, table);
		if (!rc)
			*table = pmd_val(*pmd);
	} else
		rc = 0;
	spin_unlock(&gmap->guest_table_lock);
	spin_unlock(ptl);
	radix_tree_preload_end();
	return rc;
}

/**
 * gmap_fault - resolve a fault on a guest address
 * @gmap: pointer to guest mapping meta data structure
 * @gaddr: guest address
 * @fault_flags: flags to pass down to handle_mm_fault()
 *
 * Returns 0 on success, -ENOMEM for out of memory conditions, and -EFAULT
 * if the vm address is already mapped to a different guest segment.
 */
int gmap_fault(struct gmap *gmap, unsigned long gaddr,
	       unsigned int fault_flags)
{
	unsigned long vmaddr;
	int rc;
	bool unlocked;

	down_read(&gmap->mm->mmap_sem);

retry:
	unlocked = false;
	vmaddr = __gmap_translate(gmap, gaddr);
	if (IS_ERR_VALUE(vmaddr)) {
		rc = vmaddr;
		goto out_up;
	}
	if (fixup_user_fault(current, gmap->mm, vmaddr, fault_flags,
			     &unlocked)) {
		rc = -EFAULT;
		goto out_up;
	}
	/*
	 * In the case that fixup_user_fault unlocked the mmap_sem during
	 * faultin redo __gmap_translate to not race with a map/unmap_segment.
	 */
	if (unlocked)
		goto retry;

	rc = __gmap_link(gmap, gaddr, vmaddr);
out_up:
	up_read(&gmap->mm->mmap_sem);
	return rc;
}
EXPORT_SYMBOL_GPL(gmap_fault);

/*
 * this function is assumed to be called with mmap_sem held
 */
void __gmap_zap(struct gmap *gmap, unsigned long gaddr)
{
	unsigned long vmaddr;
	spinlock_t *ptl;
	pte_t *ptep;

	/* Find the vm address for the guest address */
	vmaddr = (unsigned long) radix_tree_lookup(&gmap->guest_to_host,
						   gaddr >> PMD_SHIFT);
	if (vmaddr) {
		vmaddr |= gaddr & ~PMD_MASK;
		/* Get pointer to the page table entry */
		ptep = get_locked_pte(gmap->mm, vmaddr, &ptl);
		if (likely(ptep))
			ptep_zap_unused(gmap->mm, vmaddr, ptep, 0);
		pte_unmap_unlock(ptep, ptl);
	}
}
EXPORT_SYMBOL_GPL(__gmap_zap);

void gmap_discard(struct gmap *gmap, unsigned long from, unsigned long to)
{
	unsigned long gaddr, vmaddr, size;
	struct vm_area_struct *vma;

	down_read(&gmap->mm->mmap_sem);
	for (gaddr = from; gaddr < to;
	     gaddr = (gaddr + PMD_SIZE) & PMD_MASK) {
		/* Find the vm address for the guest address */
		vmaddr = (unsigned long)
			radix_tree_lookup(&gmap->guest_to_host,
					  gaddr >> PMD_SHIFT);
		if (!vmaddr)
			continue;
		vmaddr |= gaddr & ~PMD_MASK;
		/* Find vma in the parent mm */
		vma = find_vma(gmap->mm, vmaddr);
		size = min(to - gaddr, PMD_SIZE - (gaddr & ~PMD_MASK));
		zap_page_range(vma, vmaddr, size, NULL);
	}
	up_read(&gmap->mm->mmap_sem);
}
EXPORT_SYMBOL_GPL(gmap_discard);

static LIST_HEAD(gmap_notifier_list);
static DEFINE_SPINLOCK(gmap_notifier_lock);

/**
669
 * gmap_register_pte_notifier - register a pte invalidation callback
670 671
 * @nb: pointer to the gmap notifier block
 */
672
void gmap_register_pte_notifier(struct gmap_notifier *nb)
673 674
{
	spin_lock(&gmap_notifier_lock);
675
	list_add_rcu(&nb->list, &gmap_notifier_list);
676 677
	spin_unlock(&gmap_notifier_lock);
}
678
EXPORT_SYMBOL_GPL(gmap_register_pte_notifier);
679 680

/**
681
 * gmap_unregister_pte_notifier - remove a pte invalidation callback
682 683
 * @nb: pointer to the gmap notifier block
 */
684
void gmap_unregister_pte_notifier(struct gmap_notifier *nb)
685 686
{
	spin_lock(&gmap_notifier_lock);
687
	list_del_rcu(&nb->list);
688
	spin_unlock(&gmap_notifier_lock);
689
	synchronize_rcu();
690
}
691
EXPORT_SYMBOL_GPL(gmap_unregister_pte_notifier);
692

693 694 695 696 697 698 699 700 701 702 703 704 705 706 707
/**
 * gmap_call_notifier - call all registered invalidation callbacks
 * @gmap: pointer to guest mapping meta data structure
 * @start: start virtual address in the guest address space
 * @end: end virtual address in the guest address space
 */
static void gmap_call_notifier(struct gmap *gmap, unsigned long start,
			       unsigned long end)
{
	struct gmap_notifier *nb;

	list_for_each_entry(nb, &gmap_notifier_list, list)
		nb->notifier_call(gmap, start, end);
}

708
/**
709 710 711
 * gmap_table_walk - walk the gmap page tables
 * @gmap: pointer to guest mapping meta data structure
 * @gaddr: virtual address in the guest address space
712 713 714 715 716 717 718 719 720 721 722
 * @level: page table level to stop at
 *
 * Returns a table entry pointer for the given guest address and @level
 * @level=0 : returns a pointer to a page table table entry (or NULL)
 * @level=1 : returns a pointer to a segment table entry (or NULL)
 * @level=2 : returns a pointer to a region-3 table entry (or NULL)
 * @level=3 : returns a pointer to a region-2 table entry (or NULL)
 * @level=4 : returns a pointer to a region-1 table entry (or NULL)
 *
 * Returns NULL if the gmap page tables could not be walked to the
 * requested level.
723
 *
724
 * Note: Can also be called for shadow gmaps.
725 726
 */
static inline unsigned long *gmap_table_walk(struct gmap *gmap,
727
					     unsigned long gaddr, int level)
728 729 730
{
	unsigned long *table;

731 732 733 734 735 736
	if ((gmap->asce & _ASCE_TYPE_MASK) + 4 < (level * 4))
		return NULL;
	if (gmap_is_shadow(gmap) && gmap->removed)
		return NULL;
	if (gaddr & (-1UL << (31 + ((gmap->asce & _ASCE_TYPE_MASK) >> 2)*11)))
		return NULL;
737 738 739 740
	table = gmap->table;
	switch (gmap->asce & _ASCE_TYPE_MASK) {
	case _ASCE_TYPE_REGION1:
		table += (gaddr >> 53) & 0x7ff;
741 742
		if (level == 4)
			break;
743 744 745 746 747 748
		if (*table & _REGION_ENTRY_INVALID)
			return NULL;
		table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN);
		/* Fallthrough */
	case _ASCE_TYPE_REGION2:
		table += (gaddr >> 42) & 0x7ff;
749 750
		if (level == 3)
			break;
751 752 753 754 755 756
		if (*table & _REGION_ENTRY_INVALID)
			return NULL;
		table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN);
		/* Fallthrough */
	case _ASCE_TYPE_REGION3:
		table += (gaddr >> 31) & 0x7ff;
757 758
		if (level == 2)
			break;
759 760 761 762 763 764
		if (*table & _REGION_ENTRY_INVALID)
			return NULL;
		table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN);
		/* Fallthrough */
	case _ASCE_TYPE_SEGMENT:
		table += (gaddr >> 20) & 0x7ff;
765 766 767 768 769 770
		if (level == 1)
			break;
		if (*table & _REGION_ENTRY_INVALID)
			return NULL;
		table = (unsigned long *)(*table & _SEGMENT_ENTRY_ORIGIN);
		table += (gaddr >> 12) & 0xff;
771 772 773 774 775 776 777 778 779 780 781 782
	}
	return table;
}

/**
 * gmap_pte_op_walk - walk the gmap page table, get the page table lock
 *		      and return the pte pointer
 * @gmap: pointer to guest mapping meta data structure
 * @gaddr: virtual address in the guest address space
 * @ptl: pointer to the spinlock pointer
 *
 * Returns a pointer to the locked pte for a guest address, or NULL
783 784
 *
 * Note: Can also be called for shadow gmaps.
785 786 787 788 789 790
 */
static pte_t *gmap_pte_op_walk(struct gmap *gmap, unsigned long gaddr,
			       spinlock_t **ptl)
{
	unsigned long *table;

791 792
	if (gmap_is_shadow(gmap))
		spin_lock(&gmap->guest_table_lock);
793
	/* Walk the gmap page table, lock and get pte pointer */
794 795 796 797
	table = gmap_table_walk(gmap, gaddr, 1); /* get segment pointer */
	if (!table || *table & _SEGMENT_ENTRY_INVALID) {
		if (gmap_is_shadow(gmap))
			spin_unlock(&gmap->guest_table_lock);
798
		return NULL;
799 800 801 802 803
	}
	if (gmap_is_shadow(gmap)) {
		*ptl = &gmap->guest_table_lock;
		return pte_offset_map((pmd_t *) table, gaddr);
	}
804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822
	return pte_alloc_map_lock(gmap->mm, (pmd_t *) table, gaddr, ptl);
}

/**
 * gmap_pte_op_fixup - force a page in and connect the gmap page table
 * @gmap: pointer to guest mapping meta data structure
 * @gaddr: virtual address in the guest address space
 * @vmaddr: address in the host process address space
 *
 * Returns 0 if the caller can retry __gmap_translate (might fail again),
 * -ENOMEM if out of memory and -EFAULT if anything goes wrong while fixing
 * up or connecting the gmap page table.
 */
static int gmap_pte_op_fixup(struct gmap *gmap, unsigned long gaddr,
			     unsigned long vmaddr)
{
	struct mm_struct *mm = gmap->mm;
	bool unlocked = false;

823
	BUG_ON(gmap_is_shadow(gmap));
824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841
	if (fixup_user_fault(current, mm, vmaddr, FAULT_FLAG_WRITE, &unlocked))
		return -EFAULT;
	if (unlocked)
		/* lost mmap_sem, caller has to retry __gmap_translate */
		return 0;
	/* Connect the page tables */
	return __gmap_link(gmap, gaddr, vmaddr);
}

/**
 * gmap_pte_op_end - release the page table lock
 * @ptl: pointer to the spinlock pointer
 */
static void gmap_pte_op_end(spinlock_t *ptl)
{
	spin_unlock(ptl);
}

842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886
/*
 * gmap_protect_range - remove access rights to memory and set pgste bits
 * @gmap: pointer to guest mapping meta data structure
 * @gaddr: virtual address in the guest address space
 * @len: size of area
 * @prot: indicates access rights: PROT_NONE, PROT_READ or PROT_WRITE
 * @bits: pgste notification bits to set
 *
 * Returns 0 if successfully protected, -ENOMEM if out of memory and
 * -EFAULT if gaddr is invalid (or mapping for shadows is missing).
 *
 * Called with sg->mm->mmap_sem in read.
 *
 * Note: Can also be called for shadow gmaps.
 */
static int gmap_protect_range(struct gmap *gmap, unsigned long gaddr,
			      unsigned long len, int prot, unsigned long bits)
{
	unsigned long vmaddr;
	spinlock_t *ptl;
	pte_t *ptep;
	int rc;

	while (len) {
		rc = -EAGAIN;
		ptep = gmap_pte_op_walk(gmap, gaddr, &ptl);
		if (ptep) {
			rc = ptep_force_prot(gmap->mm, gaddr, ptep, prot, bits);
			gmap_pte_op_end(ptl);
		}
		if (rc) {
			vmaddr = __gmap_translate(gmap, gaddr);
			if (IS_ERR_VALUE(vmaddr))
				return vmaddr;
			rc = gmap_pte_op_fixup(gmap, gaddr, vmaddr);
			if (rc)
				return rc;
			continue;
		}
		gaddr += PAGE_SIZE;
		len -= PAGE_SIZE;
	}
	return 0;
}

887 888 889
/**
 * gmap_mprotect_notify - change access rights for a range of ptes and
 *                        call the notifier if any pte changes again
890 891 892
 * @gmap: pointer to guest mapping meta data structure
 * @gaddr: virtual address in the guest address space
 * @len: size of area
893
 * @prot: indicates access rights: PROT_NONE, PROT_READ or PROT_WRITE
894
 *
895 896 897 898 899
 * Returns 0 if for each page in the given range a gmap mapping exists,
 * the new access rights could be set and the notifier could be armed.
 * If the gmap mapping is missing for one or more pages -EFAULT is
 * returned. If no memory could be allocated -ENOMEM is returned.
 * This function establishes missing page table entries.
900
 */
901 902
int gmap_mprotect_notify(struct gmap *gmap, unsigned long gaddr,
			 unsigned long len, int prot)
903
{
904
	int rc;
905

906
	if ((gaddr & ~PAGE_MASK) || (len & ~PAGE_MASK) || gmap_is_shadow(gmap))
907
		return -EINVAL;
908 909
	if (!MACHINE_HAS_ESOP && prot == PROT_READ)
		return -EINVAL;
910
	down_read(&gmap->mm->mmap_sem);
911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936
	rc = gmap_protect_range(gmap, gaddr, len, prot, PGSTE_IN_BIT);
	up_read(&gmap->mm->mmap_sem);
	return rc;
}
EXPORT_SYMBOL_GPL(gmap_mprotect_notify);

/**
 * gmap_read_table - get an unsigned long value from a guest page table using
 *                   absolute addressing, without marking the page referenced.
 * @gmap: pointer to guest mapping meta data structure
 * @gaddr: virtual address in the guest address space
 * @val: pointer to the unsigned long value to return
 *
 * Returns 0 if the value was read, -ENOMEM if out of memory and -EFAULT
 * if reading using the virtual address failed.
 *
 * Called with gmap->mm->mmap_sem in read.
 */
int gmap_read_table(struct gmap *gmap, unsigned long gaddr, unsigned long *val)
{
	unsigned long address, vmaddr;
	spinlock_t *ptl;
	pte_t *ptep, pte;
	int rc;

	while (1) {
937 938 939
		rc = -EAGAIN;
		ptep = gmap_pte_op_walk(gmap, gaddr, &ptl);
		if (ptep) {
940 941 942 943 944 945 946 947 948
			pte = *ptep;
			if (pte_present(pte) && (pte_val(pte) & _PAGE_READ)) {
				address = pte_val(pte) & PAGE_MASK;
				address += gaddr & ~PAGE_MASK;
				*val = *(unsigned long *) address;
				pte_val(*ptep) |= _PAGE_YOUNG;
				/* Do *NOT* clear the _PAGE_INVALID bit! */
				rc = 0;
			}
949
			gmap_pte_op_end(ptl);
950
		}
951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985 986 987 988 989 990 991 992 993 994 995 996 997 998 999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023
		if (!rc)
			break;
		vmaddr = __gmap_translate(gmap, gaddr);
		if (IS_ERR_VALUE(vmaddr)) {
			rc = vmaddr;
			break;
		}
		rc = gmap_pte_op_fixup(gmap, gaddr, vmaddr);
		if (rc)
			break;
	}
	return rc;
}
EXPORT_SYMBOL_GPL(gmap_read_table);

/**
 * gmap_insert_rmap - add a rmap to the host_to_rmap radix tree
 * @sg: pointer to the shadow guest address space structure
 * @vmaddr: vm address associated with the rmap
 * @rmap: pointer to the rmap structure
 *
 * Called with the sg->guest_table_lock
 */
static inline void gmap_insert_rmap(struct gmap *sg, unsigned long vmaddr,
				    struct gmap_rmap *rmap)
{
	void **slot;

	BUG_ON(!gmap_is_shadow(sg));
	slot = radix_tree_lookup_slot(&sg->host_to_rmap, vmaddr >> PAGE_SHIFT);
	if (slot) {
		rmap->next = radix_tree_deref_slot_protected(slot,
							&sg->guest_table_lock);
		radix_tree_replace_slot(slot, rmap);
	} else {
		rmap->next = NULL;
		radix_tree_insert(&sg->host_to_rmap, vmaddr >> PAGE_SHIFT,
				  rmap);
	}
}

/**
 * gmap_protect_rmap - modify access rights to memory and create an rmap
 * @sg: pointer to the shadow guest address space structure
 * @raddr: rmap address in the shadow gmap
 * @paddr: address in the parent guest address space
 * @len: length of the memory area to protect
 * @prot: indicates access rights: none, read-only or read-write
 *
 * Returns 0 if successfully protected and the rmap was created, -ENOMEM
 * if out of memory and -EFAULT if paddr is invalid.
 */
static int gmap_protect_rmap(struct gmap *sg, unsigned long raddr,
			     unsigned long paddr, unsigned long len, int prot)
{
	struct gmap *parent;
	struct gmap_rmap *rmap;
	unsigned long vmaddr;
	spinlock_t *ptl;
	pte_t *ptep;
	int rc;

	BUG_ON(!gmap_is_shadow(sg));
	parent = sg->parent;
	while (len) {
		vmaddr = __gmap_translate(parent, paddr);
		if (IS_ERR_VALUE(vmaddr))
			return vmaddr;
		rmap = kzalloc(sizeof(*rmap), GFP_KERNEL);
		if (!rmap)
			return -ENOMEM;
		rmap->raddr = raddr;
		rc = radix_tree_preload(GFP_KERNEL);
1024
		if (rc) {
1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042
			kfree(rmap);
			return rc;
		}
		rc = -EAGAIN;
		ptep = gmap_pte_op_walk(parent, paddr, &ptl);
		if (ptep) {
			spin_lock(&sg->guest_table_lock);
			rc = ptep_force_prot(parent->mm, paddr, ptep, prot,
					     PGSTE_VSIE_BIT);
			if (!rc)
				gmap_insert_rmap(sg, vmaddr, rmap);
			spin_unlock(&sg->guest_table_lock);
			gmap_pte_op_end(ptl);
		}
		radix_tree_preload_end();
		if (rc) {
			kfree(rmap);
			rc = gmap_pte_op_fixup(parent, paddr, vmaddr);
1043
			if (rc)
1044
				return rc;
1045 1046
			continue;
		}
1047
		paddr += PAGE_SIZE;
1048
		len -= PAGE_SIZE;
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 1083 1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113 1114 1115 1116 1117 1118 1119 1120 1121 1122 1123 1124 1125 1126 1127
	return 0;
}

#define _SHADOW_RMAP_MASK	0x7
#define _SHADOW_RMAP_REGION1	0x5
#define _SHADOW_RMAP_REGION2	0x4
#define _SHADOW_RMAP_REGION3	0x3
#define _SHADOW_RMAP_SEGMENT	0x2
#define _SHADOW_RMAP_PGTABLE	0x1

/**
 * gmap_idte_one - invalidate a single region or segment table entry
 * @asce: region or segment table *origin* + table-type bits
 * @vaddr: virtual address to identify the table entry to flush
 *
 * The invalid bit of a single region or segment table entry is set
 * and the associated TLB entries depending on the entry are flushed.
 * The table-type of the @asce identifies the portion of the @vaddr
 * that is used as the invalidation index.
 */
static inline void gmap_idte_one(unsigned long asce, unsigned long vaddr)
{
	asm volatile(
		"	.insn	rrf,0xb98e0000,%0,%1,0,0"
		: : "a" (asce), "a" (vaddr) : "cc", "memory");
}

/**
 * gmap_unshadow_page - remove a page from a shadow page table
 * @sg: pointer to the shadow guest address space structure
 * @raddr: rmap address in the shadow guest address space
 *
 * Called with the sg->guest_table_lock
 */
static void gmap_unshadow_page(struct gmap *sg, unsigned long raddr)
{
	unsigned long *table;

	BUG_ON(!gmap_is_shadow(sg));
	table = gmap_table_walk(sg, raddr, 0); /* get page table pointer */
	if (!table || *table & _PAGE_INVALID)
		return;
	gmap_call_notifier(sg, raddr, raddr + (1UL << 12) - 1);
	ptep_unshadow_pte(sg->mm, raddr, (pte_t *) table);
}

/**
 * __gmap_unshadow_pgt - remove all entries from a shadow page table
 * @sg: pointer to the shadow guest address space structure
 * @raddr: rmap address in the shadow guest address space
 * @pgt: pointer to the start of a shadow page table
 *
 * Called with the sg->guest_table_lock
 */
static void __gmap_unshadow_pgt(struct gmap *sg, unsigned long raddr,
				unsigned long *pgt)
{
	int i;

	BUG_ON(!gmap_is_shadow(sg));
	for (i = 0; i < 256; i++, raddr += 1UL << 12)
		pgt[i] = _PAGE_INVALID;
}

/**
 * gmap_unshadow_pgt - remove a shadow page table from a segment entry
 * @sg: pointer to the shadow guest address space structure
 * @raddr: address in the shadow guest address space
 *
 * Called with the sg->guest_table_lock
 */
static void gmap_unshadow_pgt(struct gmap *sg, unsigned long raddr)
{
	unsigned long sto, *ste, *pgt;
	struct page *page;

	BUG_ON(!gmap_is_shadow(sg));
	ste = gmap_table_walk(sg, raddr, 1); /* get segment pointer */
1128
	if (!ste || !(*ste & _SEGMENT_ENTRY_ORIGIN))
1129 1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155 1156 1157 1158 1159
		return;
	gmap_call_notifier(sg, raddr, raddr + (1UL << 20) - 1);
	sto = (unsigned long) (ste - ((raddr >> 20) & 0x7ff));
	gmap_idte_one(sto | _ASCE_TYPE_SEGMENT, raddr);
	pgt = (unsigned long *)(*ste & _SEGMENT_ENTRY_ORIGIN);
	*ste = _SEGMENT_ENTRY_EMPTY;
	__gmap_unshadow_pgt(sg, raddr, pgt);
	/* Free page table */
	page = pfn_to_page(__pa(pgt) >> PAGE_SHIFT);
	list_del(&page->lru);
	page_table_free_pgste(page);
}

/**
 * __gmap_unshadow_sgt - remove all entries from a shadow segment table
 * @sg: pointer to the shadow guest address space structure
 * @raddr: rmap address in the shadow guest address space
 * @sgt: pointer to the start of a shadow segment table
 *
 * Called with the sg->guest_table_lock
 */
static void __gmap_unshadow_sgt(struct gmap *sg, unsigned long raddr,
				unsigned long *sgt)
{
	unsigned long asce, *pgt;
	struct page *page;
	int i;

	BUG_ON(!gmap_is_shadow(sg));
	asce = (unsigned long) sgt | _ASCE_TYPE_SEGMENT;
	for (i = 0; i < 2048; i++, raddr += 1UL << 20) {
1160
		if (!(sgt[i] & _SEGMENT_ENTRY_ORIGIN))
1161 1162 1163 1164 1165 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175 1176 1177 1178 1179 1180 1181 1182 1183 1184 1185
			continue;
		pgt = (unsigned long *)(sgt[i] & _REGION_ENTRY_ORIGIN);
		sgt[i] = _SEGMENT_ENTRY_EMPTY;
		__gmap_unshadow_pgt(sg, raddr, pgt);
		/* Free page table */
		page = pfn_to_page(__pa(pgt) >> PAGE_SHIFT);
		list_del(&page->lru);
		page_table_free_pgste(page);
	}
}

/**
 * gmap_unshadow_sgt - remove a shadow segment table from a region-3 entry
 * @sg: pointer to the shadow guest address space structure
 * @raddr: rmap address in the shadow guest address space
 *
 * Called with the shadow->guest_table_lock
 */
static void gmap_unshadow_sgt(struct gmap *sg, unsigned long raddr)
{
	unsigned long r3o, *r3e, *sgt;
	struct page *page;

	BUG_ON(!gmap_is_shadow(sg));
	r3e = gmap_table_walk(sg, raddr, 2); /* get region-3 pointer */
1186
	if (!r3e || !(*r3e & _REGION_ENTRY_ORIGIN))
1187 1188 1189 1190 1191 1192 1193 1194 1195 1196 1197 1198 1199 1200 1201 1202 1203 1204 1205 1206 1207 1208 1209 1210 1211 1212 1213 1214 1215 1216 1217
		return;
	gmap_call_notifier(sg, raddr, raddr + (1UL << 31) - 1);
	r3o = (unsigned long) (r3e - ((raddr >> 31) & 0x7ff));
	gmap_idte_one(r3o | _ASCE_TYPE_REGION3, raddr);
	sgt = (unsigned long *)(*r3e & _REGION_ENTRY_ORIGIN);
	*r3e = _REGION3_ENTRY_EMPTY;
	__gmap_unshadow_sgt(sg, raddr, sgt);
	/* Free segment table */
	page = pfn_to_page(__pa(sgt) >> PAGE_SHIFT);
	list_del(&page->lru);
	__free_pages(page, 2);
}

/**
 * __gmap_unshadow_r3t - remove all entries from a shadow region-3 table
 * @sg: pointer to the shadow guest address space structure
 * @raddr: address in the shadow guest address space
 * @r3t: pointer to the start of a shadow region-3 table
 *
 * Called with the sg->guest_table_lock
 */
static void __gmap_unshadow_r3t(struct gmap *sg, unsigned long raddr,
				unsigned long *r3t)
{
	unsigned long asce, *sgt;
	struct page *page;
	int i;

	BUG_ON(!gmap_is_shadow(sg));
	asce = (unsigned long) r3t | _ASCE_TYPE_REGION3;
	for (i = 0; i < 2048; i++, raddr += 1UL << 31) {
1218
		if (!(r3t[i] & _REGION_ENTRY_ORIGIN))
1219 1220 1221 1222 1223 1224 1225 1226 1227 1228 1229 1230 1231 1232 1233 1234 1235 1236 1237 1238 1239 1240 1241 1242 1243
			continue;
		sgt = (unsigned long *)(r3t[i] & _REGION_ENTRY_ORIGIN);
		r3t[i] = _REGION3_ENTRY_EMPTY;
		__gmap_unshadow_sgt(sg, raddr, sgt);
		/* Free segment table */
		page = pfn_to_page(__pa(sgt) >> PAGE_SHIFT);
		list_del(&page->lru);
		__free_pages(page, 2);
	}
}

/**
 * gmap_unshadow_r3t - remove a shadow region-3 table from a region-2 entry
 * @sg: pointer to the shadow guest address space structure
 * @raddr: rmap address in the shadow guest address space
 *
 * Called with the sg->guest_table_lock
 */
static void gmap_unshadow_r3t(struct gmap *sg, unsigned long raddr)
{
	unsigned long r2o, *r2e, *r3t;
	struct page *page;

	BUG_ON(!gmap_is_shadow(sg));
	r2e = gmap_table_walk(sg, raddr, 3); /* get region-2 pointer */
1244
	if (!r2e || !(*r2e & _REGION_ENTRY_ORIGIN))
1245 1246 1247 1248 1249 1250 1251 1252 1253 1254 1255 1256 1257 1258 1259 1260 1261 1262 1263 1264 1265 1266 1267 1268 1269 1270 1271 1272 1273 1274 1275
		return;
	gmap_call_notifier(sg, raddr, raddr + (1UL << 42) - 1);
	r2o = (unsigned long) (r2e - ((raddr >> 42) & 0x7ff));
	gmap_idte_one(r2o | _ASCE_TYPE_REGION2, raddr);
	r3t = (unsigned long *)(*r2e & _REGION_ENTRY_ORIGIN);
	*r2e = _REGION2_ENTRY_EMPTY;
	__gmap_unshadow_r3t(sg, raddr, r3t);
	/* Free region 3 table */
	page = pfn_to_page(__pa(r3t) >> PAGE_SHIFT);
	list_del(&page->lru);
	__free_pages(page, 2);
}

/**
 * __gmap_unshadow_r2t - remove all entries from a shadow region-2 table
 * @sg: pointer to the shadow guest address space structure
 * @raddr: rmap address in the shadow guest address space
 * @r2t: pointer to the start of a shadow region-2 table
 *
 * Called with the sg->guest_table_lock
 */
static void __gmap_unshadow_r2t(struct gmap *sg, unsigned long raddr,
				unsigned long *r2t)
{
	unsigned long asce, *r3t;
	struct page *page;
	int i;

	BUG_ON(!gmap_is_shadow(sg));
	asce = (unsigned long) r2t | _ASCE_TYPE_REGION2;
	for (i = 0; i < 2048; i++, raddr += 1UL << 42) {
1276
		if (!(r2t[i] & _REGION_ENTRY_ORIGIN))
1277 1278 1279 1280 1281 1282 1283 1284 1285 1286 1287 1288 1289 1290 1291 1292 1293 1294 1295 1296 1297 1298 1299 1300 1301
			continue;
		r3t = (unsigned long *)(r2t[i] & _REGION_ENTRY_ORIGIN);
		r2t[i] = _REGION2_ENTRY_EMPTY;
		__gmap_unshadow_r3t(sg, raddr, r3t);
		/* Free region 3 table */
		page = pfn_to_page(__pa(r3t) >> PAGE_SHIFT);
		list_del(&page->lru);
		__free_pages(page, 2);
	}
}

/**
 * gmap_unshadow_r2t - remove a shadow region-2 table from a region-1 entry
 * @sg: pointer to the shadow guest address space structure
 * @raddr: rmap address in the shadow guest address space
 *
 * Called with the sg->guest_table_lock
 */
static void gmap_unshadow_r2t(struct gmap *sg, unsigned long raddr)
{
	unsigned long r1o, *r1e, *r2t;
	struct page *page;

	BUG_ON(!gmap_is_shadow(sg));
	r1e = gmap_table_walk(sg, raddr, 4); /* get region-1 pointer */
1302
	if (!r1e || !(*r1e & _REGION_ENTRY_ORIGIN))
1303 1304 1305 1306 1307 1308 1309 1310 1311 1312 1313 1314 1315 1316 1317 1318 1319 1320 1321 1322 1323 1324 1325 1326 1327 1328 1329 1330 1331 1332 1333
		return;
	gmap_call_notifier(sg, raddr, raddr + (1UL << 53) - 1);
	r1o = (unsigned long) (r1e - ((raddr >> 53) & 0x7ff));
	gmap_idte_one(r1o | _ASCE_TYPE_REGION1, raddr);
	r2t = (unsigned long *)(*r1e & _REGION_ENTRY_ORIGIN);
	*r1e = _REGION1_ENTRY_EMPTY;
	__gmap_unshadow_r2t(sg, raddr, r2t);
	/* Free region 2 table */
	page = pfn_to_page(__pa(r2t) >> PAGE_SHIFT);
	list_del(&page->lru);
	__free_pages(page, 2);
}

/**
 * __gmap_unshadow_r1t - remove all entries from a shadow region-1 table
 * @sg: pointer to the shadow guest address space structure
 * @raddr: rmap address in the shadow guest address space
 * @r1t: pointer to the start of a shadow region-1 table
 *
 * Called with the shadow->guest_table_lock
 */
static void __gmap_unshadow_r1t(struct gmap *sg, unsigned long raddr,
				unsigned long *r1t)
{
	unsigned long asce, *r2t;
	struct page *page;
	int i;

	BUG_ON(!gmap_is_shadow(sg));
	asce = (unsigned long) r1t | _ASCE_TYPE_REGION1;
	for (i = 0; i < 2048; i++, raddr += 1UL << 53) {
1334
		if (!(r1t[i] & _REGION_ENTRY_ORIGIN))
1335 1336 1337 1338 1339 1340 1341 1342 1343 1344 1345 1346 1347 1348 1349 1350 1351 1352 1353 1354 1355 1356 1357 1358 1359 1360 1361 1362
			continue;
		r2t = (unsigned long *)(r1t[i] & _REGION_ENTRY_ORIGIN);
		__gmap_unshadow_r2t(sg, raddr, r2t);
		/* Clear entry and flush translation r1t -> r2t */
		gmap_idte_one(asce, raddr);
		r1t[i] = _REGION1_ENTRY_EMPTY;
		/* Free region 2 table */
		page = pfn_to_page(__pa(r2t) >> PAGE_SHIFT);
		list_del(&page->lru);
		__free_pages(page, 2);
	}
}

/**
 * gmap_unshadow - remove a shadow page table completely
 * @sg: pointer to the shadow guest address space structure
 *
 * Called with sg->guest_table_lock
 */
static void gmap_unshadow(struct gmap *sg)
{
	unsigned long *table;

	BUG_ON(!gmap_is_shadow(sg));
	if (sg->removed)
		return;
	sg->removed = 1;
	gmap_call_notifier(sg, 0, -1UL);
1363
	gmap_flush_tlb(sg);
1364 1365 1366 1367 1368 1369 1370 1371 1372 1373 1374 1375 1376 1377 1378 1379 1380 1381 1382 1383 1384 1385 1386 1387 1388 1389 1390 1391 1392 1393 1394 1395 1396 1397 1398 1399 1400 1401 1402 1403 1404 1405 1406 1407 1408 1409 1410 1411 1412 1413 1414 1415 1416 1417 1418 1419 1420 1421 1422 1423 1424 1425 1426 1427 1428 1429 1430 1431 1432 1433 1434 1435 1436 1437 1438 1439 1440 1441 1442 1443 1444 1445 1446 1447 1448 1449 1450 1451 1452 1453 1454 1455 1456 1457 1458 1459 1460 1461 1462 1463 1464 1465 1466 1467 1468 1469 1470 1471 1472 1473 1474 1475 1476 1477 1478 1479 1480 1481 1482 1483 1484 1485 1486 1487 1488 1489 1490 1491 1492 1493 1494 1495 1496 1497 1498
	table = (unsigned long *)(sg->asce & _ASCE_ORIGIN);
	switch (sg->asce & _ASCE_TYPE_MASK) {
	case _ASCE_TYPE_REGION1:
		__gmap_unshadow_r1t(sg, 0, table);
		break;
	case _ASCE_TYPE_REGION2:
		__gmap_unshadow_r2t(sg, 0, table);
		break;
	case _ASCE_TYPE_REGION3:
		__gmap_unshadow_r3t(sg, 0, table);
		break;
	case _ASCE_TYPE_SEGMENT:
		__gmap_unshadow_sgt(sg, 0, table);
		break;
	}
}

/**
 * gmap_find_shadow - find a specific asce in the list of shadow tables
 * @parent: pointer to the parent gmap
 * @asce: ASCE for which the shadow table is created
 *
 * Returns the pointer to a gmap if a shadow table with the given asce is
 * already available, otherwise NULL
 */
static struct gmap *gmap_find_shadow(struct gmap *parent, unsigned long asce)
{
	struct gmap *sg;

	list_for_each_entry(sg, &parent->children, list) {
		if (sg->orig_asce != asce || sg->removed)
			continue;
		atomic_inc(&sg->ref_count);
		return sg;
	}
	return NULL;
}

/**
 * gmap_shadow - create/find a shadow guest address space
 * @parent: pointer to the parent gmap
 * @asce: ASCE for which the shadow table is created
 *
 * The pages of the top level page table referred by the asce parameter
 * will be set to read-only and marked in the PGSTEs of the kvm process.
 * The shadow table will be removed automatically on any change to the
 * PTE mapping for the source table.
 *
 * Returns a guest address space structure, NULL if out of memory or if
 * anything goes wrong while protecting the top level pages.
 */
struct gmap *gmap_shadow(struct gmap *parent, unsigned long asce)
{
	struct gmap *sg, *new;
	unsigned long limit;
	int rc;

	BUG_ON(gmap_is_shadow(parent));
	spin_lock(&parent->shadow_lock);
	sg = gmap_find_shadow(parent, asce);
	spin_unlock(&parent->shadow_lock);
	if (sg)
		return sg;
	/* Create a new shadow gmap */
	limit = -1UL >> (33 - (((asce & _ASCE_TYPE_MASK) >> 2) * 11));
	new = gmap_alloc(limit);
	if (!new)
		return NULL;
	new->mm = parent->mm;
	new->parent = gmap_get(parent);
	new->orig_asce = asce;
	down_read(&parent->mm->mmap_sem);
	rc = gmap_protect_range(parent, asce & _ASCE_ORIGIN,
				((asce & _ASCE_TABLE_LENGTH) + 1) * 4096,
				PROT_READ, PGSTE_VSIE_BIT);
	up_read(&parent->mm->mmap_sem);
	if (rc) {
		atomic_set(&new->ref_count, 2);
		spin_lock(&parent->shadow_lock);
		/* Recheck if another CPU created the same shadow */
		sg = gmap_find_shadow(parent, asce);
		if (!sg) {
			list_add(&new->list, &parent->children);
			sg = new;
			new = NULL;
		}
		spin_unlock(&parent->shadow_lock);
	}
	if (new)
		gmap_free(new);
	return sg;
}
EXPORT_SYMBOL_GPL(gmap_shadow);

/**
 * gmap_shadow_r2t - create an empty shadow region 2 table
 * @sg: pointer to the shadow guest address space structure
 * @saddr: faulting address in the shadow gmap
 * @r2t: parent gmap address of the region 2 table to get shadowed
 *
 * The r2t parameter specifies the address of the source table. The
 * four pages of the source table are made read-only in the parent gmap
 * address space. A write to the source table area @r2t will automatically
 * remove the shadow r2 table and all of its decendents.
 *
 * Returns 0 if successfully shadowed or already shadowed, -EAGAIN if the
 * shadow table structure is incomplete, -ENOMEM if out of memory and
 * -EFAULT if an address in the parent gmap could not be resolved.
 *
 * Called with sg->mm->mmap_sem in read.
 */
int gmap_shadow_r2t(struct gmap *sg, unsigned long saddr, unsigned long r2t)
{
	unsigned long raddr, origin, offset, len;
	unsigned long *s_r2t, *table;
	struct page *page;
	int rc;

	BUG_ON(!gmap_is_shadow(sg));
	/* Allocate a shadow region second table */
	page = alloc_pages(GFP_KERNEL, 2);
	if (!page)
		return -ENOMEM;
	page->index = r2t & _REGION_ENTRY_ORIGIN;
	s_r2t = (unsigned long *) page_to_phys(page);
	/* Install shadow region second table */
	spin_lock(&sg->guest_table_lock);
	table = gmap_table_walk(sg, saddr, 4); /* get region-1 pointer */
	if (!table) {
		rc = -EAGAIN;		/* Race with unshadow */
		goto out_free;
	}
	if (!(*table & _REGION_ENTRY_INVALID)) {
		rc = 0;			/* Already established */
		goto out_free;
1499 1500 1501
	} else if (*table & _REGION_ENTRY_ORIGIN) {
		rc = -EAGAIN;		/* Race with shadow */
		goto out_free;
1502 1503
	}
	crst_table_init(s_r2t, _REGION2_ENTRY_EMPTY);
1504 1505 1506
	/* mark as invalid as long as the parent table is not protected */
	*table = (unsigned long) s_r2t | _REGION_ENTRY_LENGTH |
		 _REGION_ENTRY_TYPE_R1 | _REGION_ENTRY_INVALID;
1507 1508 1509 1510 1511 1512 1513 1514
	list_add(&page->lru, &sg->crst_list);
	spin_unlock(&sg->guest_table_lock);
	/* Make r2t read-only in parent gmap page table */
	raddr = (saddr & 0xffe0000000000000UL) | _SHADOW_RMAP_REGION1;
	origin = r2t & _REGION_ENTRY_ORIGIN;
	offset = ((r2t & _REGION_ENTRY_OFFSET) >> 6) * 4096;
	len = ((r2t & _REGION_ENTRY_LENGTH) + 1) * 4096 - offset;
	rc = gmap_protect_rmap(sg, raddr, origin + offset, len, PROT_READ);
1515 1516 1517 1518 1519 1520 1521 1522 1523
	spin_lock(&sg->guest_table_lock);
	if (!rc) {
		table = gmap_table_walk(sg, saddr, 4);
		if (!table || (*table & _REGION_ENTRY_ORIGIN) !=
			      (unsigned long) s_r2t)
			rc = -EAGAIN;		/* Race with unshadow */
		else
			*table &= ~_REGION_ENTRY_INVALID;
	} else {
1524 1525
		gmap_unshadow_r2t(sg, raddr);
	}
1526
	spin_unlock(&sg->guest_table_lock);
1527 1528 1529 1530
	return rc;
out_free:
	spin_unlock(&sg->guest_table_lock);
	__free_pages(page, 2);
1531 1532
	return rc;
}
1533 1534 1535 1536 1537 1538 1539 1540 1541 1542 1543 1544 1545 1546 1547 1548 1549 1550 1551 1552 1553 1554 1555 1556 1557 1558 1559 1560 1561 1562 1563 1564 1565 1566 1567 1568 1569 1570
EXPORT_SYMBOL_GPL(gmap_shadow_r2t);

/**
 * gmap_shadow_r3t - create a shadow region 3 table
 * @sg: pointer to the shadow guest address space structure
 * @saddr: faulting address in the shadow gmap
 * @r3t: parent gmap address of the region 3 table to get shadowed
 *
 * Returns 0 if successfully shadowed or already shadowed, -EAGAIN if the
 * shadow table structure is incomplete, -ENOMEM if out of memory and
 * -EFAULT if an address in the parent gmap could not be resolved.
 *
 * Called with sg->mm->mmap_sem in read.
 */
int gmap_shadow_r3t(struct gmap *sg, unsigned long saddr, unsigned long r3t)
{
	unsigned long raddr, origin, offset, len;
	unsigned long *s_r3t, *table;
	struct page *page;
	int rc;

	BUG_ON(!gmap_is_shadow(sg));
	/* Allocate a shadow region second table */
	page = alloc_pages(GFP_KERNEL, 2);
	if (!page)
		return -ENOMEM;
	page->index = r3t & _REGION_ENTRY_ORIGIN;
	s_r3t = (unsigned long *) page_to_phys(page);
	/* Install shadow region second table */
	spin_lock(&sg->guest_table_lock);
	table = gmap_table_walk(sg, saddr, 3); /* get region-2 pointer */
	if (!table) {
		rc = -EAGAIN;		/* Race with unshadow */
		goto out_free;
	}
	if (!(*table & _REGION_ENTRY_INVALID)) {
		rc = 0;			/* Already established */
		goto out_free;
1571 1572
	} else if (*table & _REGION_ENTRY_ORIGIN) {
		rc = -EAGAIN;		/* Race with shadow */
1573 1574
	}
	crst_table_init(s_r3t, _REGION3_ENTRY_EMPTY);
1575 1576 1577
	/* mark as invalid as long as the parent table is not protected */
	*table = (unsigned long) s_r3t | _REGION_ENTRY_LENGTH |
		 _REGION_ENTRY_TYPE_R2 | _REGION_ENTRY_INVALID;
1578 1579 1580 1581 1582 1583 1584 1585
	list_add(&page->lru, &sg->crst_list);
	spin_unlock(&sg->guest_table_lock);
	/* Make r3t read-only in parent gmap page table */
	raddr = (saddr & 0xfffffc0000000000UL) | _SHADOW_RMAP_REGION2;
	origin = r3t & _REGION_ENTRY_ORIGIN;
	offset = ((r3t & _REGION_ENTRY_OFFSET) >> 6) * 4096;
	len = ((r3t & _REGION_ENTRY_LENGTH) + 1) * 4096 - offset;
	rc = gmap_protect_rmap(sg, raddr, origin + offset, len, PROT_READ);
1586 1587 1588 1589 1590 1591 1592 1593 1594
	spin_lock(&sg->guest_table_lock);
	if (!rc) {
		table = gmap_table_walk(sg, saddr, 3);
		if (!table || (*table & _REGION_ENTRY_ORIGIN) !=
			      (unsigned long) s_r3t)
			rc = -EAGAIN;		/* Race with unshadow */
		else
			*table &= ~_REGION_ENTRY_INVALID;
	} else {
1595 1596
		gmap_unshadow_r3t(sg, raddr);
	}
1597
	spin_unlock(&sg->guest_table_lock);
1598 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 1628 1629 1630 1631 1632 1633 1634 1635 1636 1637 1638 1639 1640 1641
	return rc;
out_free:
	spin_unlock(&sg->guest_table_lock);
	__free_pages(page, 2);
	return rc;
}
EXPORT_SYMBOL_GPL(gmap_shadow_r3t);

/**
 * gmap_shadow_sgt - create a shadow segment table
 * @sg: pointer to the shadow guest address space structure
 * @saddr: faulting address in the shadow gmap
 * @sgt: parent gmap address of the segment table to get shadowed
 *
 * Returns: 0 if successfully shadowed or already shadowed, -EAGAIN if the
 * shadow table structure is incomplete, -ENOMEM if out of memory and
 * -EFAULT if an address in the parent gmap could not be resolved.
 *
 * Called with sg->mm->mmap_sem in read.
 */
int gmap_shadow_sgt(struct gmap *sg, unsigned long saddr, unsigned long sgt)
{
	unsigned long raddr, origin, offset, len;
	unsigned long *s_sgt, *table;
	struct page *page;
	int rc;

	BUG_ON(!gmap_is_shadow(sg));
	/* Allocate a shadow segment table */
	page = alloc_pages(GFP_KERNEL, 2);
	if (!page)
		return -ENOMEM;
	page->index = sgt & _REGION_ENTRY_ORIGIN;
	s_sgt = (unsigned long *) page_to_phys(page);
	/* Install shadow region second table */
	spin_lock(&sg->guest_table_lock);
	table = gmap_table_walk(sg, saddr, 2); /* get region-3 pointer */
	if (!table) {
		rc = -EAGAIN;		/* Race with unshadow */
		goto out_free;
	}
	if (!(*table & _REGION_ENTRY_INVALID)) {
		rc = 0;			/* Already established */
		goto out_free;
1642 1643 1644
	} else if (*table & _REGION_ENTRY_ORIGIN) {
		rc = -EAGAIN;		/* Race with shadow */
		goto out_free;
1645 1646
	}
	crst_table_init(s_sgt, _SEGMENT_ENTRY_EMPTY);
1647 1648 1649
	/* mark as invalid as long as the parent table is not protected */
	*table = (unsigned long) s_sgt | _REGION_ENTRY_LENGTH |
		 _REGION_ENTRY_TYPE_R3 | _REGION_ENTRY_INVALID;
1650 1651 1652 1653 1654 1655 1656 1657
	list_add(&page->lru, &sg->crst_list);
	spin_unlock(&sg->guest_table_lock);
	/* Make sgt read-only in parent gmap page table */
	raddr = (saddr & 0xffffffff80000000UL) | _SHADOW_RMAP_REGION3;
	origin = sgt & _REGION_ENTRY_ORIGIN;
	offset = ((sgt & _REGION_ENTRY_OFFSET) >> 6) * 4096;
	len = ((sgt & _REGION_ENTRY_LENGTH) + 1) * 4096 - offset;
	rc = gmap_protect_rmap(sg, raddr, origin + offset, len, PROT_READ);
1658 1659 1660 1661 1662 1663 1664 1665 1666
	spin_lock(&sg->guest_table_lock);
	if (!rc) {
		table = gmap_table_walk(sg, saddr, 2);
		if (!table || (*table & _REGION_ENTRY_ORIGIN) !=
			      (unsigned long) s_sgt)
			rc = -EAGAIN;		/* Race with unshadow */
		else
			*table &= ~_REGION_ENTRY_INVALID;
	} else {
1667 1668
		gmap_unshadow_sgt(sg, raddr);
	}
1669
	spin_unlock(&sg->guest_table_lock);
1670 1671 1672 1673 1674 1675 1676 1677 1678 1679 1680 1681 1682 1683 1684 1685 1686 1687 1688 1689 1690 1691 1692 1693 1694 1695 1696 1697 1698 1699 1700 1701 1702 1703 1704 1705 1706 1707 1708 1709 1710 1711 1712 1713 1714 1715 1716 1717 1718 1719 1720 1721 1722 1723 1724 1725 1726 1727 1728 1729 1730 1731 1732 1733 1734 1735 1736 1737 1738 1739 1740 1741 1742 1743 1744 1745 1746 1747 1748 1749 1750
	return rc;
out_free:
	spin_unlock(&sg->guest_table_lock);
	__free_pages(page, 2);
	return rc;
}
EXPORT_SYMBOL_GPL(gmap_shadow_sgt);

/**
 * gmap_shadow_lookup_pgtable - find a shadow page table
 * @sg: pointer to the shadow guest address space structure
 * @saddr: the address in the shadow aguest address space
 * @pgt: parent gmap address of the page table to get shadowed
 * @dat_protection: if the pgtable is marked as protected by dat
 *
 * Returns 0 if the shadow page table was found and -EAGAIN if the page
 * table was not found.
 *
 * Called with sg->mm->mmap_sem in read.
 */
int gmap_shadow_pgt_lookup(struct gmap *sg, unsigned long saddr,
			   unsigned long *pgt, int *dat_protection)
{
	unsigned long *table;
	struct page *page;
	int rc;

	BUG_ON(!gmap_is_shadow(sg));
	spin_lock(&sg->guest_table_lock);
	table = gmap_table_walk(sg, saddr, 1); /* get segment pointer */
	if (table && !(*table & _SEGMENT_ENTRY_INVALID)) {
		/* Shadow page tables are full pages (pte+pgste) */
		page = pfn_to_page(*table >> PAGE_SHIFT);
		*pgt = page->index;
		*dat_protection = !!(*table & _SEGMENT_ENTRY_PROTECT);
		rc = 0;
	} else  {
		rc = -EAGAIN;
	}
	spin_unlock(&sg->guest_table_lock);
	return rc;

}
EXPORT_SYMBOL_GPL(gmap_shadow_pgt_lookup);

/**
 * gmap_shadow_pgt - instantiate a shadow page table
 * @sg: pointer to the shadow guest address space structure
 * @saddr: faulting address in the shadow gmap
 * @pgt: parent gmap address of the page table to get shadowed
 *
 * Returns 0 if successfully shadowed or already shadowed, -EAGAIN if the
 * shadow table structure is incomplete, -ENOMEM if out of memory,
 * -EFAULT if an address in the parent gmap could not be resolved and
 *
 * Called with gmap->mm->mmap_sem in read
 */
int gmap_shadow_pgt(struct gmap *sg, unsigned long saddr, unsigned long pgt)
{
	unsigned long raddr, origin;
	unsigned long *s_pgt, *table;
	struct page *page;
	int rc;

	BUG_ON(!gmap_is_shadow(sg));
	/* Allocate a shadow page table */
	page = page_table_alloc_pgste(sg->mm);
	if (!page)
		return -ENOMEM;
	page->index = pgt & _SEGMENT_ENTRY_ORIGIN;
	s_pgt = (unsigned long *) page_to_phys(page);
	/* Install shadow page table */
	spin_lock(&sg->guest_table_lock);
	table = gmap_table_walk(sg, saddr, 1); /* get segment pointer */
	if (!table) {
		rc = -EAGAIN;		/* Race with unshadow */
		goto out_free;
	}
	if (!(*table & _SEGMENT_ENTRY_INVALID)) {
		rc = 0;			/* Already established */
		goto out_free;
1751 1752 1753
	} else if (*table & _SEGMENT_ENTRY_ORIGIN) {
		rc = -EAGAIN;		/* Race with shadow */
		goto out_free;
1754
	}
1755
	/* mark as invalid as long as the parent table is not protected */
1756
	*table = (unsigned long) s_pgt | _SEGMENT_ENTRY |
1757
		 (pgt & _SEGMENT_ENTRY_PROTECT) | _SEGMENT_ENTRY_INVALID;
1758 1759 1760 1761 1762 1763
	list_add(&page->lru, &sg->pt_list);
	spin_unlock(&sg->guest_table_lock);
	/* Make pgt read-only in parent gmap page table (not the pgste) */
	raddr = (saddr & 0xfffffffffff00000UL) | _SHADOW_RMAP_SEGMENT;
	origin = pgt & _SEGMENT_ENTRY_ORIGIN & PAGE_MASK;
	rc = gmap_protect_rmap(sg, raddr, origin, PAGE_SIZE, PROT_READ);
1764 1765 1766 1767 1768 1769 1770 1771 1772
	spin_lock(&sg->guest_table_lock);
	if (!rc) {
		table = gmap_table_walk(sg, saddr, 1);
		if (!table || (*table & _SEGMENT_ENTRY_ORIGIN) !=
			      (unsigned long) s_pgt)
			rc = -EAGAIN;		/* Race with unshadow */
		else
			*table &= ~_SEGMENT_ENTRY_INVALID;
	} else {
1773 1774
		gmap_unshadow_pgt(sg, raddr);
	}
1775
	spin_unlock(&sg->guest_table_lock);
1776 1777 1778 1779 1780 1781 1782 1783 1784 1785 1786 1787 1788
	return rc;
out_free:
	spin_unlock(&sg->guest_table_lock);
	page_table_free_pgste(page);
	return rc;

}
EXPORT_SYMBOL_GPL(gmap_shadow_pgt);

/**
 * gmap_shadow_page - create a shadow page mapping
 * @sg: pointer to the shadow guest address space structure
 * @saddr: faulting address in the shadow gmap
1789
 * @pte: pte in parent gmap address space to get shadowed
1790 1791 1792 1793 1794 1795 1796
 *
 * Returns 0 if successfully shadowed or already shadowed, -EAGAIN if the
 * shadow table structure is incomplete, -ENOMEM if out of memory and
 * -EFAULT if an address in the parent gmap could not be resolved.
 *
 * Called with sg->mm->mmap_sem in read.
 */
1797
int gmap_shadow_page(struct gmap *sg, unsigned long saddr, pte_t pte)
1798 1799 1800
{
	struct gmap *parent;
	struct gmap_rmap *rmap;
1801
	unsigned long vmaddr, paddr;
1802 1803 1804 1805 1806 1807 1808 1809 1810 1811 1812 1813 1814
	spinlock_t *ptl;
	pte_t *sptep, *tptep;
	int rc;

	BUG_ON(!gmap_is_shadow(sg));
	parent = sg->parent;

	rmap = kzalloc(sizeof(*rmap), GFP_KERNEL);
	if (!rmap)
		return -ENOMEM;
	rmap->raddr = (saddr & PAGE_MASK) | _SHADOW_RMAP_PGTABLE;

	while (1) {
1815
		paddr = pte_val(pte) & PAGE_MASK;
1816 1817 1818 1819 1820 1821 1822 1823 1824 1825 1826 1827 1828 1829 1830 1831 1832 1833 1834 1835
		vmaddr = __gmap_translate(parent, paddr);
		if (IS_ERR_VALUE(vmaddr)) {
			rc = vmaddr;
			break;
		}
		rc = radix_tree_preload(GFP_KERNEL);
		if (rc)
			break;
		rc = -EAGAIN;
		sptep = gmap_pte_op_walk(parent, paddr, &ptl);
		if (sptep) {
			spin_lock(&sg->guest_table_lock);
			/* Get page table pointer */
			tptep = (pte_t *) gmap_table_walk(sg, saddr, 0);
			if (!tptep) {
				spin_unlock(&sg->guest_table_lock);
				gmap_pte_op_end(ptl);
				radix_tree_preload_end();
				break;
			}
1836
			rc = ptep_shadow_pte(sg->mm, saddr, sptep, tptep, pte);
1837 1838 1839 1840 1841 1842 1843 1844 1845 1846 1847 1848 1849 1850 1851 1852 1853 1854 1855 1856 1857 1858 1859 1860 1861 1862 1863 1864 1865 1866 1867 1868 1869 1870 1871 1872 1873 1874 1875 1876 1877 1878 1879 1880 1881 1882 1883 1884 1885 1886 1887 1888 1889 1890 1891 1892 1893 1894 1895 1896 1897 1898 1899 1900 1901 1902 1903 1904 1905 1906 1907 1908 1909 1910 1911 1912 1913 1914 1915 1916 1917 1918 1919 1920
			if (rc > 0) {
				/* Success and a new mapping */
				gmap_insert_rmap(sg, vmaddr, rmap);
				rmap = NULL;
				rc = 0;
			}
			gmap_pte_op_end(ptl);
			spin_unlock(&sg->guest_table_lock);
		}
		radix_tree_preload_end();
		if (!rc)
			break;
		rc = gmap_pte_op_fixup(parent, paddr, vmaddr);
		if (rc)
			break;
	}
	kfree(rmap);
	return rc;
}
EXPORT_SYMBOL_GPL(gmap_shadow_page);

/**
 * gmap_shadow_notify - handle notifications for shadow gmap
 *
 * Called with sg->parent->shadow_lock.
 */
static void gmap_shadow_notify(struct gmap *sg, unsigned long vmaddr,
			       unsigned long offset, pte_t *pte)
{
	struct gmap_rmap *rmap, *rnext, *head;
	unsigned long gaddr, start, end, bits, raddr;
	unsigned long *table;

	BUG_ON(!gmap_is_shadow(sg));
	spin_lock(&sg->parent->guest_table_lock);
	table = radix_tree_lookup(&sg->parent->host_to_guest,
				  vmaddr >> PMD_SHIFT);
	gaddr = table ? __gmap_segment_gaddr(table) + offset : 0;
	spin_unlock(&sg->parent->guest_table_lock);
	if (!table)
		return;

	spin_lock(&sg->guest_table_lock);
	if (sg->removed) {
		spin_unlock(&sg->guest_table_lock);
		return;
	}
	/* Check for top level table */
	start = sg->orig_asce & _ASCE_ORIGIN;
	end = start + ((sg->orig_asce & _ASCE_TABLE_LENGTH) + 1) * 4096;
	if (gaddr >= start && gaddr < end) {
		/* The complete shadow table has to go */
		gmap_unshadow(sg);
		spin_unlock(&sg->guest_table_lock);
		list_del(&sg->list);
		gmap_put(sg);
		return;
	}
	/* Remove the page table tree from on specific entry */
	head = radix_tree_delete(&sg->host_to_rmap, vmaddr >> 12);
	gmap_for_each_rmap_safe(rmap, rnext, head) {
		bits = rmap->raddr & _SHADOW_RMAP_MASK;
		raddr = rmap->raddr ^ bits;
		switch (bits) {
		case _SHADOW_RMAP_REGION1:
			gmap_unshadow_r2t(sg, raddr);
			break;
		case _SHADOW_RMAP_REGION2:
			gmap_unshadow_r3t(sg, raddr);
			break;
		case _SHADOW_RMAP_REGION3:
			gmap_unshadow_sgt(sg, raddr);
			break;
		case _SHADOW_RMAP_SEGMENT:
			gmap_unshadow_pgt(sg, raddr);
			break;
		case _SHADOW_RMAP_PGTABLE:
			gmap_unshadow_page(sg, raddr);
			break;
		}
		kfree(rmap);
	}
	spin_unlock(&sg->guest_table_lock);
}
1921 1922 1923 1924 1925 1926

/**
 * ptep_notify - call all invalidation callbacks for a specific pte.
 * @mm: pointer to the process mm_struct
 * @addr: virtual address in the process address space
 * @pte: pointer to the page table entry
1927
 * @bits: bits from the pgste that caused the notify call
1928 1929 1930 1931
 *
 * This function is assumed to be called with the page table lock held
 * for the pte to notify.
 */
1932 1933
void ptep_notify(struct mm_struct *mm, unsigned long vmaddr,
		 pte_t *pte, unsigned long bits)
1934 1935 1936
{
	unsigned long offset, gaddr;
	unsigned long *table;
1937
	struct gmap *gmap, *sg, *next;
1938 1939 1940

	offset = ((unsigned long) pte) & (255 * sizeof(pte_t));
	offset = offset * (4096 / sizeof(pte_t));
1941 1942
	rcu_read_lock();
	list_for_each_entry_rcu(gmap, &mm->context.gmap_list, list) {
1943 1944 1945 1946 1947 1948 1949 1950 1951
		if (!list_empty(&gmap->children) && (bits & PGSTE_VSIE_BIT)) {
			spin_lock(&gmap->shadow_lock);
			list_for_each_entry_safe(sg, next,
						 &gmap->children, list)
				gmap_shadow_notify(sg, vmaddr, offset, pte);
			spin_unlock(&gmap->shadow_lock);
		}
		if (!(bits & PGSTE_IN_BIT))
			continue;
1952
		spin_lock(&gmap->guest_table_lock);
1953 1954
		table = radix_tree_lookup(&gmap->host_to_guest,
					  vmaddr >> PMD_SHIFT);
1955 1956 1957 1958 1959
		if (table)
			gaddr = __gmap_segment_gaddr(table) + offset;
		spin_unlock(&gmap->guest_table_lock);
		if (table)
			gmap_call_notifier(gmap, gaddr, gaddr + PAGE_SIZE - 1);
1960
	}
1961
	rcu_read_unlock();
1962 1963 1964 1965 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023 2024 2025 2026 2027 2028 2029 2030 2031 2032 2033 2034 2035 2036 2037 2038 2039 2040 2041 2042 2043 2044 2045 2046 2047 2048 2049 2050 2051 2052 2053 2054 2055 2056 2057 2058 2059 2060 2061 2062 2063 2064 2065 2066 2067 2068 2069 2070 2071 2072 2073 2074
}
EXPORT_SYMBOL_GPL(ptep_notify);

static inline void thp_split_mm(struct mm_struct *mm)
{
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
	struct vm_area_struct *vma;
	unsigned long addr;

	for (vma = mm->mmap; vma != NULL; vma = vma->vm_next) {
		for (addr = vma->vm_start;
		     addr < vma->vm_end;
		     addr += PAGE_SIZE)
			follow_page(vma, addr, FOLL_SPLIT);
		vma->vm_flags &= ~VM_HUGEPAGE;
		vma->vm_flags |= VM_NOHUGEPAGE;
	}
	mm->def_flags |= VM_NOHUGEPAGE;
#endif
}

/*
 * switch on pgstes for its userspace process (for kvm)
 */
int s390_enable_sie(void)
{
	struct mm_struct *mm = current->mm;

	/* Do we have pgstes? if yes, we are done */
	if (mm_has_pgste(mm))
		return 0;
	/* Fail if the page tables are 2K */
	if (!mm_alloc_pgste(mm))
		return -EINVAL;
	down_write(&mm->mmap_sem);
	mm->context.has_pgste = 1;
	/* split thp mappings and disable thp for future mappings */
	thp_split_mm(mm);
	up_write(&mm->mmap_sem);
	return 0;
}
EXPORT_SYMBOL_GPL(s390_enable_sie);

/*
 * Enable storage key handling from now on and initialize the storage
 * keys with the default key.
 */
static int __s390_enable_skey(pte_t *pte, unsigned long addr,
			      unsigned long next, struct mm_walk *walk)
{
	/*
	 * Remove all zero page mappings,
	 * after establishing a policy to forbid zero page mappings
	 * following faults for that page will get fresh anonymous pages
	 */
	if (is_zero_pfn(pte_pfn(*pte)))
		ptep_xchg_direct(walk->mm, addr, pte, __pte(_PAGE_INVALID));
	/* Clear storage key */
	ptep_zap_key(walk->mm, addr, pte);
	return 0;
}

int s390_enable_skey(void)
{
	struct mm_walk walk = { .pte_entry = __s390_enable_skey };
	struct mm_struct *mm = current->mm;
	struct vm_area_struct *vma;
	int rc = 0;

	down_write(&mm->mmap_sem);
	if (mm_use_skey(mm))
		goto out_up;

	mm->context.use_skey = 1;
	for (vma = mm->mmap; vma; vma = vma->vm_next) {
		if (ksm_madvise(vma, vma->vm_start, vma->vm_end,
				MADV_UNMERGEABLE, &vma->vm_flags)) {
			mm->context.use_skey = 0;
			rc = -ENOMEM;
			goto out_up;
		}
	}
	mm->def_flags &= ~VM_MERGEABLE;

	walk.mm = mm;
	walk_page_range(0, TASK_SIZE, &walk);

out_up:
	up_write(&mm->mmap_sem);
	return rc;
}
EXPORT_SYMBOL_GPL(s390_enable_skey);

/*
 * Reset CMMA state, make all pages stable again.
 */
static int __s390_reset_cmma(pte_t *pte, unsigned long addr,
			     unsigned long next, struct mm_walk *walk)
{
	ptep_zap_unused(walk->mm, addr, pte, 1);
	return 0;
}

void s390_reset_cmma(struct mm_struct *mm)
{
	struct mm_walk walk = { .pte_entry = __s390_reset_cmma };

	down_write(&mm->mmap_sem);
	walk.mm = mm;
	walk_page_range(0, TASK_SIZE, &walk);
	up_write(&mm->mmap_sem);
}
EXPORT_SYMBOL_GPL(s390_reset_cmma);