mmu.c 57.6 KB
Newer Older
J
Jeremy Fitzhardinge 已提交
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40
/*
 * Xen mmu operations
 *
 * This file contains the various mmu fetch and update operations.
 * The most important job they must perform is the mapping between the
 * domain's pfn and the overall machine mfns.
 *
 * Xen allows guests to directly update the pagetable, in a controlled
 * fashion.  In other words, the guest modifies the same pagetable
 * that the CPU actually uses, which eliminates the overhead of having
 * a separate shadow pagetable.
 *
 * In order to allow this, it falls on the guest domain to map its
 * notion of a "physical" pfn - which is just a domain-local linear
 * address - into a real "machine address" which the CPU's MMU can
 * use.
 *
 * A pgd_t/pmd_t/pte_t will typically contain an mfn, and so can be
 * inserted directly into the pagetable.  When creating a new
 * pte/pmd/pgd, it converts the passed pfn into an mfn.  Conversely,
 * when reading the content back with __(pgd|pmd|pte)_val, it converts
 * the mfn back into a pfn.
 *
 * The other constraint is that all pages which make up a pagetable
 * must be mapped read-only in the guest.  This prevents uncontrolled
 * guest updates to the pagetable.  Xen strictly enforces this, and
 * will disallow any pagetable update which will end up mapping a
 * pagetable page RW, and will disallow using any writable page as a
 * pagetable.
 *
 * Naively, when loading %cr3 with the base of a new pagetable, Xen
 * would need to validate the whole pagetable before going on.
 * Naturally, this is quite slow.  The solution is to "pin" a
 * pagetable, which enforces all the constraints on the pagetable even
 * when it is not actively in use.  This menas that Xen can be assured
 * that it is still valid when you do load it into %cr3, and doesn't
 * need to revalidate it.
 *
 * Jeremy Fitzhardinge <jeremy@xensource.com>, XenSource Inc, 2007
 */
41
#include <linux/sched.h>
42
#include <linux/highmem.h>
J
Jeremy Fitzhardinge 已提交
43
#include <linux/debugfs.h>
J
Jeremy Fitzhardinge 已提交
44
#include <linux/bug.h>
45
#include <linux/vmalloc.h>
46
#include <linux/module.h>
47
#include <linux/gfp.h>
48
#include <linux/memblock.h>
49
#include <linux/seq_file.h>
J
Jeremy Fitzhardinge 已提交
50

51 52
#include <trace/events/xen.h>

J
Jeremy Fitzhardinge 已提交
53 54
#include <asm/pgtable.h>
#include <asm/tlbflush.h>
55
#include <asm/fixmap.h>
J
Jeremy Fitzhardinge 已提交
56
#include <asm/mmu_context.h>
57
#include <asm/setup.h>
58
#include <asm/paravirt.h>
59
#include <asm/e820.h>
60
#include <asm/linkage.h>
61
#include <asm/page.h>
62
#include <asm/init.h>
J
Jeremy Fitzhardinge 已提交
63
#include <asm/pat.h>
A
Andrew Jones 已提交
64
#include <asm/smp.h>
J
Jeremy Fitzhardinge 已提交
65 66

#include <asm/xen/hypercall.h>
67
#include <asm/xen/hypervisor.h>
J
Jeremy Fitzhardinge 已提交
68

69
#include <xen/xen.h>
J
Jeremy Fitzhardinge 已提交
70 71
#include <xen/page.h>
#include <xen/interface/xen.h>
72
#include <xen/interface/hvm/hvm_op.h>
73
#include <xen/interface/version.h>
74
#include <xen/interface/memory.h>
75
#include <xen/hvc-console.h>
J
Jeremy Fitzhardinge 已提交
76

77
#include "multicalls.h"
J
Jeremy Fitzhardinge 已提交
78
#include "mmu.h"
J
Jeremy Fitzhardinge 已提交
79 80
#include "debugfs.h"

A
Alex Nixon 已提交
81 82
/*
 * Protects atomic reservation decrease/increase against concurrent increases.
83
 * Also protects non-atomic updates of current_pages and balloon lists.
A
Alex Nixon 已提交
84 85 86
 */
DEFINE_SPINLOCK(xen_reservation_lock);

87 88 89 90 91
/*
 * Identity map, in addition to plain kernel map.  This needs to be
 * large enough to allocate page table pages to allocate the rest.
 * Each page can map 2MB.
 */
92 93
#define LEVEL1_IDENT_ENTRIES	(PTRS_PER_PTE * 4)
static RESERVE_BRK_ARRAY(pte_t, level1_ident_pgt, LEVEL1_IDENT_ENTRIES);
94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117

#ifdef CONFIG_X86_64
/* l3 pud for userspace vsyscall mapping */
static pud_t level3_user_vsyscall[PTRS_PER_PUD] __page_aligned_bss;
#endif /* CONFIG_X86_64 */

/*
 * Note about cr3 (pagetable base) values:
 *
 * xen_cr3 contains the current logical cr3 value; it contains the
 * last set cr3.  This may not be the current effective cr3, because
 * its update may be being lazily deferred.  However, a vcpu looking
 * at its own cr3 can use this value knowing that it everything will
 * be self-consistent.
 *
 * xen_current_cr3 contains the actual vcpu cr3; it is set once the
 * hypercall to set the vcpu cr3 is complete (so it may be a little
 * out of date, but it will never be set early).  If one vcpu is
 * looking at another vcpu's cr3 value, it should use this variable.
 */
DEFINE_PER_CPU(unsigned long, xen_cr3);	 /* cr3 stored as physaddr */
DEFINE_PER_CPU(unsigned long, xen_current_cr3);	 /* actual vcpu cr3 */


118 119 120 121 122 123
/*
 * Just beyond the highest usermode address.  STACK_TOP_MAX has a
 * redzone above it, so round it up to a PGD boundary.
 */
#define USER_LIMIT	((STACK_TOP_MAX + PGDIR_SIZE - 1) & PGDIR_MASK)

124 125 126 127 128 129 130
unsigned long arbitrary_virt_to_mfn(void *vaddr)
{
	xmaddr_t maddr = arbitrary_virt_to_machine(vaddr);

	return PFN_DOWN(maddr.maddr);
}

131
xmaddr_t arbitrary_virt_to_machine(void *vaddr)
J
Jeremy Fitzhardinge 已提交
132
{
133
	unsigned long address = (unsigned long)vaddr;
134
	unsigned int level;
135 136
	pte_t *pte;
	unsigned offset;
J
Jeremy Fitzhardinge 已提交
137

138 139 140 141 142 143 144 145
	/*
	 * if the PFN is in the linear mapped vaddr range, we can just use
	 * the (quick) virt_to_machine() p2m lookup
	 */
	if (virt_addr_valid(vaddr))
		return virt_to_machine(vaddr);

	/* otherwise we have to do a (slower) full page-table walk */
J
Jeremy Fitzhardinge 已提交
146

147 148 149
	pte = lookup_address(address, &level);
	BUG_ON(pte == NULL);
	offset = address & ~PAGE_MASK;
150
	return XMADDR(((phys_addr_t)pte_mfn(*pte) << PAGE_SHIFT) + offset);
J
Jeremy Fitzhardinge 已提交
151
}
152
EXPORT_SYMBOL_GPL(arbitrary_virt_to_machine);
J
Jeremy Fitzhardinge 已提交
153 154 155 156 157

void make_lowmem_page_readonly(void *vaddr)
{
	pte_t *pte, ptev;
	unsigned long address = (unsigned long)vaddr;
158
	unsigned int level;
J
Jeremy Fitzhardinge 已提交
159

160
	pte = lookup_address(address, &level);
161 162
	if (pte == NULL)
		return;		/* vaddr missing */
J
Jeremy Fitzhardinge 已提交
163 164 165 166 167 168 169 170 171 172 173

	ptev = pte_wrprotect(*pte);

	if (HYPERVISOR_update_va_mapping(address, ptev, 0))
		BUG();
}

void make_lowmem_page_readwrite(void *vaddr)
{
	pte_t *pte, ptev;
	unsigned long address = (unsigned long)vaddr;
174
	unsigned int level;
J
Jeremy Fitzhardinge 已提交
175

176
	pte = lookup_address(address, &level);
177 178
	if (pte == NULL)
		return;		/* vaddr missing */
J
Jeremy Fitzhardinge 已提交
179 180 181 182 183 184 185 186

	ptev = pte_mkwrite(*pte);

	if (HYPERVISOR_update_va_mapping(address, ptev, 0))
		BUG();
}


187
static bool xen_page_pinned(void *ptr)
188 189 190 191 192 193
{
	struct page *page = virt_to_page(ptr);

	return PagePinned(page);
}

194
void xen_set_domain_pte(pte_t *ptep, pte_t pteval, unsigned domid)
195 196 197 198
{
	struct multicall_space mcs;
	struct mmu_update *u;

199 200
	trace_xen_mmu_set_domain_pte(ptep, pteval, domid);

201 202 203 204
	mcs = xen_mc_entry(sizeof(*u));
	u = mcs.args;

	/* ptep might be kmapped when using 32-bit HIGHPTE */
205
	u->ptr = virt_to_machine(ptep).maddr;
206 207
	u->val = pte_val_ma(pteval);

208
	MULTI_mmu_update(mcs.mc, mcs.args, 1, NULL, domid);
209 210 211

	xen_mc_issue(PARAVIRT_LAZY_MMU);
}
212 213
EXPORT_SYMBOL_GPL(xen_set_domain_pte);

214
static void xen_extend_mmu_update(const struct mmu_update *update)
J
Jeremy Fitzhardinge 已提交
215
{
J
Jeremy Fitzhardinge 已提交
216 217
	struct multicall_space mcs;
	struct mmu_update *u;
J
Jeremy Fitzhardinge 已提交
218

219 220
	mcs = xen_mc_extend_args(__HYPERVISOR_mmu_update, sizeof(*u));

J
Jeremy Fitzhardinge 已提交
221
	if (mcs.mc != NULL) {
222
		mcs.mc->args[1]++;
J
Jeremy Fitzhardinge 已提交
223
	} else {
224 225 226
		mcs = __xen_mc_entry(sizeof(*u));
		MULTI_mmu_update(mcs.mc, mcs.args, 1, NULL, DOMID_SELF);
	}
J
Jeremy Fitzhardinge 已提交
227 228

	u = mcs.args;
229 230 231
	*u = *update;
}

232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249
static void xen_extend_mmuext_op(const struct mmuext_op *op)
{
	struct multicall_space mcs;
	struct mmuext_op *u;

	mcs = xen_mc_extend_args(__HYPERVISOR_mmuext_op, sizeof(*u));

	if (mcs.mc != NULL) {
		mcs.mc->args[1]++;
	} else {
		mcs = __xen_mc_entry(sizeof(*u));
		MULTI_mmuext_op(mcs.mc, mcs.args, 1, NULL, DOMID_SELF);
	}

	u = mcs.args;
	*u = *op;
}

250
static void xen_set_pmd_hyper(pmd_t *ptr, pmd_t val)
251 252 253 254 255 256 257
{
	struct mmu_update u;

	preempt_disable();

	xen_mc_batch();

258 259
	/* ptr may be ioremapped for 64-bit pagetable setup */
	u.ptr = arbitrary_virt_to_machine(ptr).maddr;
260
	u.val = pmd_val_ma(val);
261
	xen_extend_mmu_update(&u);
J
Jeremy Fitzhardinge 已提交
262 263 264 265

	xen_mc_issue(PARAVIRT_LAZY_MMU);

	preempt_enable();
J
Jeremy Fitzhardinge 已提交
266 267
}

268
static void xen_set_pmd(pmd_t *ptr, pmd_t val)
269
{
270 271
	trace_xen_mmu_set_pmd(ptr, val);

272 273
	/* If page is not pinned, we can just update the entry
	   directly */
274
	if (!xen_page_pinned(ptr)) {
275 276 277 278 279 280 281
		*ptr = val;
		return;
	}

	xen_set_pmd_hyper(ptr, val);
}

J
Jeremy Fitzhardinge 已提交
282 283 284 285 286 287
/*
 * Associate a virtual page frame with a given physical page frame
 * and protection flags for that frame.
 */
void set_pte_mfn(unsigned long vaddr, unsigned long mfn, pgprot_t flags)
{
J
Jeremy Fitzhardinge 已提交
288
	set_pte_vaddr(vaddr, mfn_pte(mfn, flags));
J
Jeremy Fitzhardinge 已提交
289 290
}

291
static bool xen_batched_set_pte(pte_t *ptep, pte_t pteval)
J
Jeremy Fitzhardinge 已提交
292
{
293
	struct mmu_update u;
294

295 296
	if (paravirt_get_lazy_mode() != PARAVIRT_LAZY_MMU)
		return false;
J
Jeremy Fitzhardinge 已提交
297

298
	xen_mc_batch();
J
Jeremy Fitzhardinge 已提交
299

300 301 302
	u.ptr = virt_to_machine(ptep).maddr | MMU_NORMAL_PT_UPDATE;
	u.val = pte_val_ma(pteval);
	xen_extend_mmu_update(&u);
303

304
	xen_mc_issue(PARAVIRT_LAZY_MMU);
305

306 307 308
	return true;
}

309
static inline void __xen_set_pte(pte_t *ptep, pte_t pteval)
310 311
{
	if (!xen_batched_set_pte(ptep, pteval))
312
		native_set_pte(ptep, pteval);
J
Jeremy Fitzhardinge 已提交
313 314
}

315 316 317 318 319 320
static void xen_set_pte(pte_t *ptep, pte_t pteval)
{
	trace_xen_mmu_set_pte(ptep, pteval);
	__xen_set_pte(ptep, pteval);
}

321
static void xen_set_pte_at(struct mm_struct *mm, unsigned long addr,
322 323
		    pte_t *ptep, pte_t pteval)
{
324 325
	trace_xen_mmu_set_pte_at(mm, addr, ptep, pteval);
	__xen_set_pte(ptep, pteval);
J
Jeremy Fitzhardinge 已提交
326 327
}

T
Tej 已提交
328 329
pte_t xen_ptep_modify_prot_start(struct mm_struct *mm,
				 unsigned long addr, pte_t *ptep)
J
Jeremy Fitzhardinge 已提交
330
{
331
	/* Just return the pte as-is.  We preserve the bits on commit */
332
	trace_xen_mmu_ptep_modify_prot_start(mm, addr, ptep, *ptep);
333 334 335 336 337 338
	return *ptep;
}

void xen_ptep_modify_prot_commit(struct mm_struct *mm, unsigned long addr,
				 pte_t *ptep, pte_t pte)
{
339
	struct mmu_update u;
340

341
	trace_xen_mmu_ptep_modify_prot_commit(mm, addr, ptep, pte);
342
	xen_mc_batch();
J
Jeremy Fitzhardinge 已提交
343

344
	u.ptr = virt_to_machine(ptep).maddr | MMU_PT_UPDATE_PRESERVE_AD;
345
	u.val = pte_val_ma(pte);
346
	xen_extend_mmu_update(&u);
J
Jeremy Fitzhardinge 已提交
347

348
	xen_mc_issue(PARAVIRT_LAZY_MMU);
J
Jeremy Fitzhardinge 已提交
349 350
}

J
Jeremy Fitzhardinge 已提交
351 352
/* Assume pteval_t is equivalent to all the other *val_t types. */
static pteval_t pte_mfn_to_pfn(pteval_t val)
J
Jeremy Fitzhardinge 已提交
353
{
J
Jeremy Fitzhardinge 已提交
354
	if (val & _PAGE_PRESENT) {
355
		unsigned long mfn = (val & PTE_PFN_MASK) >> PAGE_SHIFT;
J
Jeremy Fitzhardinge 已提交
356
		pteval_t flags = val & PTE_FLAGS_MASK;
357
		val = ((pteval_t)mfn_to_pfn(mfn) << PAGE_SHIFT) | flags;
J
Jeremy Fitzhardinge 已提交
358
	}
J
Jeremy Fitzhardinge 已提交
359

J
Jeremy Fitzhardinge 已提交
360
	return val;
J
Jeremy Fitzhardinge 已提交
361 362
}

J
Jeremy Fitzhardinge 已提交
363
static pteval_t pte_pfn_to_mfn(pteval_t val)
J
Jeremy Fitzhardinge 已提交
364
{
J
Jeremy Fitzhardinge 已提交
365
	if (val & _PAGE_PRESENT) {
366
		unsigned long pfn = (val & PTE_PFN_MASK) >> PAGE_SHIFT;
J
Jeremy Fitzhardinge 已提交
367
		pteval_t flags = val & PTE_FLAGS_MASK;
368
		unsigned long mfn;
369

370 371 372 373
		if (!xen_feature(XENFEAT_auto_translated_physmap))
			mfn = get_phys_to_machine(pfn);
		else
			mfn = pfn;
374 375 376 377 378 379 380 381 382
		/*
		 * If there's no mfn for the pfn, then just create an
		 * empty non-present pte.  Unfortunately this loses
		 * information about the original pfn, so
		 * pte_mfn_to_pfn is asymmetric.
		 */
		if (unlikely(mfn == INVALID_P2M_ENTRY)) {
			mfn = 0;
			flags = 0;
383 384 385 386 387 388 389 390 391 392 393
		} else {
			/*
			 * Paramount to do this test _after_ the
			 * INVALID_P2M_ENTRY as INVALID_P2M_ENTRY &
			 * IDENTITY_FRAME_BIT resolves to true.
			 */
			mfn &= ~FOREIGN_FRAME_BIT;
			if (mfn & IDENTITY_FRAME_BIT) {
				mfn &= ~IDENTITY_FRAME_BIT;
				flags |= _PAGE_IOMAP;
			}
394 395
		}
		val = ((pteval_t)mfn << PAGE_SHIFT) | flags;
J
Jeremy Fitzhardinge 已提交
396 397
	}

J
Jeremy Fitzhardinge 已提交
398
	return val;
J
Jeremy Fitzhardinge 已提交
399 400
}

401 402 403 404 405 406 407 408 409 410 411 412 413 414
static pteval_t iomap_pte(pteval_t val)
{
	if (val & _PAGE_PRESENT) {
		unsigned long pfn = (val & PTE_PFN_MASK) >> PAGE_SHIFT;
		pteval_t flags = val & PTE_FLAGS_MASK;

		/* We assume the pte frame number is a MFN, so
		   just use it as-is. */
		val = ((pteval_t)pfn << PAGE_SHIFT) | flags;
	}

	return val;
}

415
static pteval_t xen_pte_val(pte_t pte)
J
Jeremy Fitzhardinge 已提交
416
{
J
Jeremy Fitzhardinge 已提交
417
	pteval_t pteval = pte.pte;
418
#if 0
J
Jeremy Fitzhardinge 已提交
419 420 421 422 423
	/* If this is a WC pte, convert back from Xen WC to Linux WC */
	if ((pteval & (_PAGE_PAT | _PAGE_PCD | _PAGE_PWT)) == _PAGE_PAT) {
		WARN_ON(!pat_enabled);
		pteval = (pteval & ~_PAGE_PAT) | _PAGE_PWT;
	}
424
#endif
J
Jeremy Fitzhardinge 已提交
425 426 427 428
	if (xen_initial_domain() && (pteval & _PAGE_IOMAP))
		return pteval;

	return pte_mfn_to_pfn(pteval);
J
Jeremy Fitzhardinge 已提交
429
}
430
PV_CALLEE_SAVE_REGS_THUNK(xen_pte_val);
J
Jeremy Fitzhardinge 已提交
431

432
static pgdval_t xen_pgd_val(pgd_t pgd)
J
Jeremy Fitzhardinge 已提交
433
{
J
Jeremy Fitzhardinge 已提交
434
	return pte_mfn_to_pfn(pgd.pgd);
J
Jeremy Fitzhardinge 已提交
435
}
436
PV_CALLEE_SAVE_REGS_THUNK(xen_pgd_val);
J
Jeremy Fitzhardinge 已提交
437

J
Jeremy Fitzhardinge 已提交
438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462
/*
 * Xen's PAT setup is part of its ABI, though I assume entries 6 & 7
 * are reserved for now, to correspond to the Intel-reserved PAT
 * types.
 *
 * We expect Linux's PAT set as follows:
 *
 * Idx  PTE flags        Linux    Xen    Default
 * 0                     WB       WB     WB
 * 1            PWT      WC       WT     WT
 * 2        PCD          UC-      UC-    UC-
 * 3        PCD PWT      UC       UC     UC
 * 4    PAT              WB       WC     WB
 * 5    PAT     PWT      WC       WP     WT
 * 6    PAT PCD          UC-      UC     UC-
 * 7    PAT PCD PWT      UC       UC     UC
 */

void xen_set_pat(u64 pat)
{
	/* We expect Linux to use a PAT setting of
	 * UC UC- WC WB (ignoring the PAT flag) */
	WARN_ON(pat != 0x0007010600070106ull);
}

463
static pte_t xen_make_pte(pteval_t pte)
J
Jeremy Fitzhardinge 已提交
464
{
465
	phys_addr_t addr = (pte & PTE_PFN_MASK);
466
#if 0
J
Jeremy Fitzhardinge 已提交
467 468 469 470 471 472 473 474 475 476 477 478
	/* If Linux is trying to set a WC pte, then map to the Xen WC.
	 * If _PAGE_PAT is set, then it probably means it is really
	 * _PAGE_PSE, so avoid fiddling with the PAT mapping and hope
	 * things work out OK...
	 *
	 * (We should never see kernel mappings with _PAGE_PSE set,
	 * but we could see hugetlbfs mappings, I think.).
	 */
	if (pat_enabled && !WARN_ON(pte & _PAGE_PAT)) {
		if ((pte & (_PAGE_PCD | _PAGE_PWT)) == _PAGE_PWT)
			pte = (pte & ~(_PAGE_PCD | _PAGE_PWT)) | _PAGE_PAT;
	}
479
#endif
480 481 482 483 484 485 486 487
	/*
	 * Unprivileged domains are allowed to do IOMAPpings for
	 * PCI passthrough, but not map ISA space.  The ISA
	 * mappings are just dummy local mappings to keep other
	 * parts of the kernel happy.
	 */
	if (unlikely(pte & _PAGE_IOMAP) &&
	    (xen_initial_domain() || addr >= ISA_END_ADDRESS)) {
488
		pte = iomap_pte(pte);
489 490
	} else {
		pte &= ~_PAGE_IOMAP;
491
		pte = pte_pfn_to_mfn(pte);
492
	}
493

J
Jeremy Fitzhardinge 已提交
494
	return native_make_pte(pte);
J
Jeremy Fitzhardinge 已提交
495
}
496
PV_CALLEE_SAVE_REGS_THUNK(xen_make_pte);
J
Jeremy Fitzhardinge 已提交
497

498
static pgd_t xen_make_pgd(pgdval_t pgd)
J
Jeremy Fitzhardinge 已提交
499
{
J
Jeremy Fitzhardinge 已提交
500 501
	pgd = pte_pfn_to_mfn(pgd);
	return native_make_pgd(pgd);
J
Jeremy Fitzhardinge 已提交
502
}
503
PV_CALLEE_SAVE_REGS_THUNK(xen_make_pgd);
J
Jeremy Fitzhardinge 已提交
504

505
static pmdval_t xen_pmd_val(pmd_t pmd)
J
Jeremy Fitzhardinge 已提交
506
{
J
Jeremy Fitzhardinge 已提交
507
	return pte_mfn_to_pfn(pmd.pmd);
J
Jeremy Fitzhardinge 已提交
508
}
509
PV_CALLEE_SAVE_REGS_THUNK(xen_pmd_val);
510

511
static void xen_set_pud_hyper(pud_t *ptr, pud_t val)
512
{
513
	struct mmu_update u;
514

J
Jeremy Fitzhardinge 已提交
515 516
	preempt_disable();

517 518
	xen_mc_batch();

519 520
	/* ptr may be ioremapped for 64-bit pagetable setup */
	u.ptr = arbitrary_virt_to_machine(ptr).maddr;
521
	u.val = pud_val_ma(val);
522
	xen_extend_mmu_update(&u);
J
Jeremy Fitzhardinge 已提交
523 524 525 526

	xen_mc_issue(PARAVIRT_LAZY_MMU);

	preempt_enable();
527 528
}

529
static void xen_set_pud(pud_t *ptr, pud_t val)
530
{
531 532
	trace_xen_mmu_set_pud(ptr, val);

533 534
	/* If page is not pinned, we can just update the entry
	   directly */
535
	if (!xen_page_pinned(ptr)) {
536 537 538 539 540 541 542
		*ptr = val;
		return;
	}

	xen_set_pud_hyper(ptr, val);
}

543
#ifdef CONFIG_X86_PAE
544
static void xen_set_pte_atomic(pte_t *ptep, pte_t pte)
J
Jeremy Fitzhardinge 已提交
545
{
546
	trace_xen_mmu_set_pte_atomic(ptep, pte);
547
	set_64bit((u64 *)ptep, native_pte_val(pte));
J
Jeremy Fitzhardinge 已提交
548 549
}

550
static void xen_pte_clear(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
J
Jeremy Fitzhardinge 已提交
551
{
552
	trace_xen_mmu_pte_clear(mm, addr, ptep);
553 554
	if (!xen_batched_set_pte(ptep, native_make_pte(0)))
		native_pte_clear(mm, addr, ptep);
J
Jeremy Fitzhardinge 已提交
555 556
}

557
static void xen_pmd_clear(pmd_t *pmdp)
J
Jeremy Fitzhardinge 已提交
558
{
559
	trace_xen_mmu_pmd_clear(pmdp);
560
	set_pmd(pmdp, __pmd(0));
J
Jeremy Fitzhardinge 已提交
561
}
562
#endif	/* CONFIG_X86_PAE */
J
Jeremy Fitzhardinge 已提交
563

564
static pmd_t xen_make_pmd(pmdval_t pmd)
J
Jeremy Fitzhardinge 已提交
565
{
J
Jeremy Fitzhardinge 已提交
566
	pmd = pte_pfn_to_mfn(pmd);
J
Jeremy Fitzhardinge 已提交
567
	return native_make_pmd(pmd);
J
Jeremy Fitzhardinge 已提交
568
}
569
PV_CALLEE_SAVE_REGS_THUNK(xen_make_pmd);
J
Jeremy Fitzhardinge 已提交
570

571
#if PAGETABLE_LEVELS == 4
572
static pudval_t xen_pud_val(pud_t pud)
573 574 575
{
	return pte_mfn_to_pfn(pud.pud);
}
576
PV_CALLEE_SAVE_REGS_THUNK(xen_pud_val);
577

578
static pud_t xen_make_pud(pudval_t pud)
579 580 581 582 583
{
	pud = pte_pfn_to_mfn(pud);

	return native_make_pud(pud);
}
584
PV_CALLEE_SAVE_REGS_THUNK(xen_make_pud);
585

586
static pgd_t *xen_get_user_pgd(pgd_t *pgd)
587
{
588 589 590
	pgd_t *pgd_page = (pgd_t *)(((unsigned long)pgd) & PAGE_MASK);
	unsigned offset = pgd - pgd_page;
	pgd_t *user_ptr = NULL;
591

592 593 594 595 596 597
	if (offset < pgd_index(USER_LIMIT)) {
		struct page *page = virt_to_page(pgd_page);
		user_ptr = (pgd_t *)page->private;
		if (user_ptr)
			user_ptr += offset;
	}
598

599 600 601 602 603 604
	return user_ptr;
}

static void __xen_set_pgd_hyper(pgd_t *ptr, pgd_t val)
{
	struct mmu_update u;
605 606 607

	u.ptr = virt_to_machine(ptr).maddr;
	u.val = pgd_val_ma(val);
608
	xen_extend_mmu_update(&u);
609 610 611 612 613 614 615 616 617
}

/*
 * Raw hypercall-based set_pgd, intended for in early boot before
 * there's a page structure.  This implies:
 *  1. The only existing pagetable is the kernel's
 *  2. It is always pinned
 *  3. It has no user pagetable attached to it
 */
618
static void __init xen_set_pgd_hyper(pgd_t *ptr, pgd_t val)
619 620 621 622 623 624
{
	preempt_disable();

	xen_mc_batch();

	__xen_set_pgd_hyper(ptr, val);
625 626 627 628 629 630

	xen_mc_issue(PARAVIRT_LAZY_MMU);

	preempt_enable();
}

631
static void xen_set_pgd(pgd_t *ptr, pgd_t val)
632
{
633 634
	pgd_t *user_ptr = xen_get_user_pgd(ptr);

635 636
	trace_xen_mmu_set_pgd(ptr, user_ptr, val);

637 638
	/* If page is not pinned, we can just update the entry
	   directly */
639
	if (!xen_page_pinned(ptr)) {
640
		*ptr = val;
641
		if (user_ptr) {
642
			WARN_ON(xen_page_pinned(user_ptr));
643 644
			*user_ptr = val;
		}
645 646 647
		return;
	}

648 649 650 651 652 653 654 655 656
	/* If it's pinned, then we can at least batch the kernel and
	   user updates together. */
	xen_mc_batch();

	__xen_set_pgd_hyper(ptr, val);
	if (user_ptr)
		__xen_set_pgd_hyper(user_ptr, val);

	xen_mc_issue(PARAVIRT_LAZY_MMU);
657 658 659
}
#endif	/* PAGETABLE_LEVELS == 4 */

660
/*
661 662 663 664 665 666 667 668 669 670 671 672 673 674
 * (Yet another) pagetable walker.  This one is intended for pinning a
 * pagetable.  This means that it walks a pagetable and calls the
 * callback function on each page it finds making up the page table,
 * at every level.  It walks the entire pagetable, but it only bothers
 * pinning pte pages which are below limit.  In the normal case this
 * will be STACK_TOP_MAX, but at boot we need to pin up to
 * FIXADDR_TOP.
 *
 * For 32-bit the important bit is that we don't pin beyond there,
 * because then we start getting into Xen's ptes.
 *
 * For 64-bit, we must skip the Xen hole in the middle of the address
 * space, just after the big x86-64 virtual hole.
 */
I
Ian Campbell 已提交
675 676 677 678
static int __xen_pgd_walk(struct mm_struct *mm, pgd_t *pgd,
			  int (*func)(struct mm_struct *mm, struct page *,
				      enum pt_level),
			  unsigned long limit)
J
Jeremy Fitzhardinge 已提交
679
{
680
	int flush = 0;
681 682 683
	unsigned hole_low, hole_high;
	unsigned pgdidx_limit, pudidx_limit, pmdidx_limit;
	unsigned pgdidx, pudidx, pmdidx;
684

685 686 687
	/* The limit is the last byte to be touched */
	limit--;
	BUG_ON(limit >= FIXADDR_TOP);
J
Jeremy Fitzhardinge 已提交
688 689

	if (xen_feature(XENFEAT_auto_translated_physmap))
690 691
		return 0;

692 693 694 695 696
	/*
	 * 64-bit has a great big hole in the middle of the address
	 * space, which contains the Xen mappings.  On 32-bit these
	 * will end up making a zero-sized hole and so is a no-op.
	 */
697
	hole_low = pgd_index(USER_LIMIT);
698 699 700 701 702 703 704 705 706 707 708 709 710 711 712
	hole_high = pgd_index(PAGE_OFFSET);

	pgdidx_limit = pgd_index(limit);
#if PTRS_PER_PUD > 1
	pudidx_limit = pud_index(limit);
#else
	pudidx_limit = 0;
#endif
#if PTRS_PER_PMD > 1
	pmdidx_limit = pmd_index(limit);
#else
	pmdidx_limit = 0;
#endif

	for (pgdidx = 0; pgdidx <= pgdidx_limit; pgdidx++) {
713
		pud_t *pud;
J
Jeremy Fitzhardinge 已提交
714

715 716
		if (pgdidx >= hole_low && pgdidx < hole_high)
			continue;
717

718
		if (!pgd_val(pgd[pgdidx]))
J
Jeremy Fitzhardinge 已提交
719
			continue;
720

721
		pud = pud_offset(&pgd[pgdidx], 0);
J
Jeremy Fitzhardinge 已提交
722 723

		if (PTRS_PER_PUD > 1) /* not folded */
724
			flush |= (*func)(mm, virt_to_page(pud), PT_PUD);
725

726
		for (pudidx = 0; pudidx < PTRS_PER_PUD; pudidx++) {
727 728
			pmd_t *pmd;

729 730 731
			if (pgdidx == pgdidx_limit &&
			    pudidx > pudidx_limit)
				goto out;
J
Jeremy Fitzhardinge 已提交
732

733
			if (pud_none(pud[pudidx]))
J
Jeremy Fitzhardinge 已提交
734
				continue;
735

736
			pmd = pmd_offset(&pud[pudidx], 0);
J
Jeremy Fitzhardinge 已提交
737 738

			if (PTRS_PER_PMD > 1) /* not folded */
739
				flush |= (*func)(mm, virt_to_page(pmd), PT_PMD);
740

741 742 743 744 745 746 747
			for (pmdidx = 0; pmdidx < PTRS_PER_PMD; pmdidx++) {
				struct page *pte;

				if (pgdidx == pgdidx_limit &&
				    pudidx == pudidx_limit &&
				    pmdidx > pmdidx_limit)
					goto out;
J
Jeremy Fitzhardinge 已提交
748

749
				if (pmd_none(pmd[pmdidx]))
J
Jeremy Fitzhardinge 已提交
750 751
					continue;

752
				pte = pmd_page(pmd[pmdidx]);
753
				flush |= (*func)(mm, pte, PT_PTE);
J
Jeremy Fitzhardinge 已提交
754 755 756
			}
		}
	}
757

758
out:
759 760
	/* Do the top level last, so that the callbacks can use it as
	   a cue to do final things like tlb flushes. */
761
	flush |= (*func)(mm, virt_to_page(pgd), PT_PGD);
762 763

	return flush;
J
Jeremy Fitzhardinge 已提交
764 765
}

I
Ian Campbell 已提交
766 767 768 769 770 771 772 773
static int xen_pgd_walk(struct mm_struct *mm,
			int (*func)(struct mm_struct *mm, struct page *,
				    enum pt_level),
			unsigned long limit)
{
	return __xen_pgd_walk(mm, mm->pgd, func, limit);
}

774 775
/* If we're using split pte locks, then take the page's lock and
   return a pointer to it.  Otherwise return NULL. */
776
static spinlock_t *xen_pte_lock(struct page *page, struct mm_struct *mm)
777 778 779
{
	spinlock_t *ptl = NULL;

780
#if USE_SPLIT_PTLOCKS
781
	ptl = __pte_lockptr(page);
782
	spin_lock_nest_lock(ptl, &mm->page_table_lock);
783 784 785 786 787
#endif

	return ptl;
}

788
static void xen_pte_unlock(void *v)
789 790 791 792 793 794 795
{
	spinlock_t *ptl = v;
	spin_unlock(ptl);
}

static void xen_do_pin(unsigned level, unsigned long pfn)
{
796
	struct mmuext_op op;
797

798 799 800 801
	op.cmd = level;
	op.arg1.mfn = pfn_to_mfn(pfn);

	xen_extend_mmuext_op(&op);
802 803
}

804 805
static int xen_pin_page(struct mm_struct *mm, struct page *page,
			enum pt_level level)
806
{
807
	unsigned pgfl = TestSetPagePinned(page);
808 809 810 811 812 813 814 815 816 817 818 819
	int flush;

	if (pgfl)
		flush = 0;		/* already pinned */
	else if (PageHighMem(page))
		/* kmaps need flushing if we found an unpinned
		   highpage */
		flush = 1;
	else {
		void *pt = lowmem_page_address(page);
		unsigned long pfn = page_to_pfn(page);
		struct multicall_space mcs = __xen_mc_entry(0);
820
		spinlock_t *ptl;
821 822 823

		flush = 0;

824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843
		/*
		 * We need to hold the pagetable lock between the time
		 * we make the pagetable RO and when we actually pin
		 * it.  If we don't, then other users may come in and
		 * attempt to update the pagetable by writing it,
		 * which will fail because the memory is RO but not
		 * pinned, so Xen won't do the trap'n'emulate.
		 *
		 * If we're using split pte locks, we can't hold the
		 * entire pagetable's worth of locks during the
		 * traverse, because we may wrap the preempt count (8
		 * bits).  The solution is to mark RO and pin each PTE
		 * page while holding the lock.  This means the number
		 * of locks we end up holding is never more than a
		 * batch size (~32 entries, at present).
		 *
		 * If we're not using split pte locks, we needn't pin
		 * the PTE pages independently, because we're
		 * protected by the overall pagetable lock.
		 */
844 845
		ptl = NULL;
		if (level == PT_PTE)
846
			ptl = xen_pte_lock(page, mm);
847

848 849
		MULTI_update_va_mapping(mcs.mc, (unsigned long)pt,
					pfn_pte(pfn, PAGE_KERNEL_RO),
850 851
					level == PT_PGD ? UVMF_TLB_FLUSH : 0);

852
		if (ptl) {
853 854 855 856
			xen_do_pin(MMUEXT_PIN_L1_TABLE, pfn);

			/* Queue a deferred unlock for when this batch
			   is completed. */
857
			xen_mc_callback(xen_pte_unlock, ptl);
858
		}
859 860 861 862
	}

	return flush;
}
J
Jeremy Fitzhardinge 已提交
863

864 865 866
/* This is called just after a mm has been created, but it has not
   been used yet.  We need to make sure that its pagetable is all
   read-only, and can be pinned. */
867
static void __xen_pgd_pin(struct mm_struct *mm, pgd_t *pgd)
J
Jeremy Fitzhardinge 已提交
868
{
869 870
	trace_xen_mmu_pgd_pin(mm, pgd);

871
	xen_mc_batch();
J
Jeremy Fitzhardinge 已提交
872

I
Ian Campbell 已提交
873
	if (__xen_pgd_walk(mm, pgd, xen_pin_page, USER_LIMIT)) {
874
		/* re-enable interrupts for flushing */
J
Jeremy Fitzhardinge 已提交
875
		xen_mc_issue(0);
876

877
		kmap_flush_unused();
878

J
Jeremy Fitzhardinge 已提交
879 880
		xen_mc_batch();
	}
881

882 883 884 885 886 887 888
#ifdef CONFIG_X86_64
	{
		pgd_t *user_pgd = xen_get_user_pgd(pgd);

		xen_do_pin(MMUEXT_PIN_L4_TABLE, PFN_DOWN(__pa(pgd)));

		if (user_pgd) {
889
			xen_pin_page(mm, virt_to_page(user_pgd), PT_PGD);
T
Tej 已提交
890 891
			xen_do_pin(MMUEXT_PIN_L4_TABLE,
				   PFN_DOWN(__pa(user_pgd)));
892 893 894
		}
	}
#else /* CONFIG_X86_32 */
895 896
#ifdef CONFIG_X86_PAE
	/* Need to make sure unshared kernel PMD is pinnable */
897
	xen_pin_page(mm, pgd_page(pgd[pgd_index(TASK_SIZE)]),
898
		     PT_PMD);
899
#endif
900
	xen_do_pin(MMUEXT_PIN_L3_TABLE, PFN_DOWN(__pa(pgd)));
901
#endif /* CONFIG_X86_64 */
902
	xen_mc_issue(0);
J
Jeremy Fitzhardinge 已提交
903 904
}

905 906 907 908 909
static void xen_pgd_pin(struct mm_struct *mm)
{
	__xen_pgd_pin(mm, mm->pgd);
}

910 911 912 913 914
/*
 * On save, we need to pin all pagetables to make sure they get their
 * mfns turned into pfns.  Search the list for any unpinned pgds and pin
 * them (unpinned pgds are not currently in use, probably because the
 * process is under construction or destruction).
915 916 917 918
 *
 * Expected to be called in stop_machine() ("equivalent to taking
 * every spinlock in the system"), so the locking doesn't really
 * matter all that much.
919 920 921 922
 */
void xen_mm_pin_all(void)
{
	struct page *page;
923

A
Andrea Arcangeli 已提交
924
	spin_lock(&pgd_lock);
925

926 927
	list_for_each_entry(page, &pgd_list, lru) {
		if (!PagePinned(page)) {
928
			__xen_pgd_pin(&init_mm, (pgd_t *)page_address(page));
929 930 931 932
			SetPageSavePinned(page);
		}
	}

A
Andrea Arcangeli 已提交
933
	spin_unlock(&pgd_lock);
J
Jeremy Fitzhardinge 已提交
934 935
}

936 937 938 939 940
/*
 * The init_mm pagetable is really pinned as soon as its created, but
 * that's before we have page structures to store the bits.  So do all
 * the book-keeping now.
 */
941
static int __init xen_mark_pinned(struct mm_struct *mm, struct page *page,
942
				  enum pt_level level)
J
Jeremy Fitzhardinge 已提交
943
{
944 945 946
	SetPagePinned(page);
	return 0;
}
J
Jeremy Fitzhardinge 已提交
947

948
static void __init xen_mark_init_mm_pinned(void)
949
{
950
	xen_pgd_walk(&init_mm, xen_mark_pinned, FIXADDR_TOP);
951
}
J
Jeremy Fitzhardinge 已提交
952

953 954
static int xen_unpin_page(struct mm_struct *mm, struct page *page,
			  enum pt_level level)
955
{
956
	unsigned pgfl = TestClearPagePinned(page);
J
Jeremy Fitzhardinge 已提交
957

958 959 960
	if (pgfl && !PageHighMem(page)) {
		void *pt = lowmem_page_address(page);
		unsigned long pfn = page_to_pfn(page);
961 962 963
		spinlock_t *ptl = NULL;
		struct multicall_space mcs;

964 965 966 967 968 969 970
		/*
		 * Do the converse to pin_page.  If we're using split
		 * pte locks, we must be holding the lock for while
		 * the pte page is unpinned but still RO to prevent
		 * concurrent updates from seeing it in this
		 * partially-pinned state.
		 */
971
		if (level == PT_PTE) {
972
			ptl = xen_pte_lock(page, mm);
973

974 975
			if (ptl)
				xen_do_pin(MMUEXT_UNPIN_TABLE, pfn);
976 977 978
		}

		mcs = __xen_mc_entry(0);
979 980 981

		MULTI_update_va_mapping(mcs.mc, (unsigned long)pt,
					pfn_pte(pfn, PAGE_KERNEL),
982 983 984 985
					level == PT_PGD ? UVMF_TLB_FLUSH : 0);

		if (ptl) {
			/* unlock when batch completed */
986
			xen_mc_callback(xen_pte_unlock, ptl);
987
		}
988 989 990
	}

	return 0;		/* never need to flush on unpin */
J
Jeremy Fitzhardinge 已提交
991 992
}

993
/* Release a pagetables pages back as normal RW */
994
static void __xen_pgd_unpin(struct mm_struct *mm, pgd_t *pgd)
995
{
996 997
	trace_xen_mmu_pgd_unpin(mm, pgd);

998 999
	xen_mc_batch();

1000
	xen_do_pin(MMUEXT_UNPIN_TABLE, PFN_DOWN(__pa(pgd)));
1001

1002 1003 1004 1005 1006
#ifdef CONFIG_X86_64
	{
		pgd_t *user_pgd = xen_get_user_pgd(pgd);

		if (user_pgd) {
T
Tej 已提交
1007 1008
			xen_do_pin(MMUEXT_UNPIN_TABLE,
				   PFN_DOWN(__pa(user_pgd)));
1009
			xen_unpin_page(mm, virt_to_page(user_pgd), PT_PGD);
1010 1011 1012 1013
		}
	}
#endif

1014 1015
#ifdef CONFIG_X86_PAE
	/* Need to make sure unshared kernel PMD is unpinned */
1016
	xen_unpin_page(mm, pgd_page(pgd[pgd_index(TASK_SIZE)]),
1017
		       PT_PMD);
1018
#endif
1019

I
Ian Campbell 已提交
1020
	__xen_pgd_walk(mm, pgd, xen_unpin_page, USER_LIMIT);
1021 1022 1023

	xen_mc_issue(0);
}
J
Jeremy Fitzhardinge 已提交
1024

1025 1026 1027 1028 1029
static void xen_pgd_unpin(struct mm_struct *mm)
{
	__xen_pgd_unpin(mm, mm->pgd);
}

1030 1031 1032 1033 1034 1035 1036 1037
/*
 * On resume, undo any pinning done at save, so that the rest of the
 * kernel doesn't see any unexpected pinned pagetables.
 */
void xen_mm_unpin_all(void)
{
	struct page *page;

A
Andrea Arcangeli 已提交
1038
	spin_lock(&pgd_lock);
1039 1040 1041 1042

	list_for_each_entry(page, &pgd_list, lru) {
		if (PageSavePinned(page)) {
			BUG_ON(!PagePinned(page));
1043
			__xen_pgd_unpin(&init_mm, (pgd_t *)page_address(page));
1044 1045 1046 1047
			ClearPageSavePinned(page);
		}
	}

A
Andrea Arcangeli 已提交
1048
	spin_unlock(&pgd_lock);
1049 1050
}

1051
static void xen_activate_mm(struct mm_struct *prev, struct mm_struct *next)
J
Jeremy Fitzhardinge 已提交
1052
{
1053
	spin_lock(&next->page_table_lock);
1054
	xen_pgd_pin(next);
1055
	spin_unlock(&next->page_table_lock);
J
Jeremy Fitzhardinge 已提交
1056 1057
}

1058
static void xen_dup_mmap(struct mm_struct *oldmm, struct mm_struct *mm)
J
Jeremy Fitzhardinge 已提交
1059
{
1060
	spin_lock(&mm->page_table_lock);
1061
	xen_pgd_pin(mm);
1062
	spin_unlock(&mm->page_table_lock);
J
Jeremy Fitzhardinge 已提交
1063 1064 1065
}


J
Jeremy Fitzhardinge 已提交
1066 1067 1068 1069 1070 1071
#ifdef CONFIG_SMP
/* Another cpu may still have their %cr3 pointing at the pagetable, so
   we need to repoint it somewhere else before we can unpin it. */
static void drop_other_mm_ref(void *info)
{
	struct mm_struct *mm = info;
1072
	struct mm_struct *active_mm;
J
Jeremy Fitzhardinge 已提交
1073

1074
	active_mm = this_cpu_read(cpu_tlbstate.active_mm);
1075

1076
	if (active_mm == mm && this_cpu_read(cpu_tlbstate.state) != TLBSTATE_OK)
J
Jeremy Fitzhardinge 已提交
1077
		leave_mm(smp_processor_id());
1078 1079 1080

	/* If this cpu still has a stale cr3 reference, then make sure
	   it has been flushed. */
1081
	if (this_cpu_read(xen_current_cr3) == __pa(mm->pgd))
1082
		load_cr3(swapper_pg_dir);
J
Jeremy Fitzhardinge 已提交
1083
}
J
Jeremy Fitzhardinge 已提交
1084

1085
static void xen_drop_mm_ref(struct mm_struct *mm)
J
Jeremy Fitzhardinge 已提交
1086
{
1087
	cpumask_var_t mask;
1088 1089
	unsigned cpu;

J
Jeremy Fitzhardinge 已提交
1090 1091 1092 1093 1094
	if (current->active_mm == mm) {
		if (current->mm == mm)
			load_cr3(swapper_pg_dir);
		else
			leave_mm(smp_processor_id());
1095 1096 1097
	}

	/* Get the "official" set of cpus referring to our pagetable. */
1098 1099
	if (!alloc_cpumask_var(&mask, GFP_ATOMIC)) {
		for_each_online_cpu(cpu) {
1100
			if (!cpumask_test_cpu(cpu, mm_cpumask(mm))
1101 1102 1103 1104 1105 1106
			    && per_cpu(xen_current_cr3, cpu) != __pa(mm->pgd))
				continue;
			smp_call_function_single(cpu, drop_other_mm_ref, mm, 1);
		}
		return;
	}
1107
	cpumask_copy(mask, mm_cpumask(mm));
1108 1109 1110 1111 1112 1113 1114 1115

	/* It's possible that a vcpu may have a stale reference to our
	   cr3, because its in lazy mode, and it hasn't yet flushed
	   its set of pending hypercalls yet.  In this case, we can
	   look at its actual current cr3 value, and force it to flush
	   if needed. */
	for_each_online_cpu(cpu) {
		if (per_cpu(xen_current_cr3, cpu) == __pa(mm->pgd))
1116
			cpumask_set_cpu(cpu, mask);
J
Jeremy Fitzhardinge 已提交
1117 1118
	}

1119 1120 1121
	if (!cpumask_empty(mask))
		smp_call_function_many(mask, drop_other_mm_ref, mm, 1);
	free_cpumask_var(mask);
J
Jeremy Fitzhardinge 已提交
1122 1123
}
#else
1124
static void xen_drop_mm_ref(struct mm_struct *mm)
J
Jeremy Fitzhardinge 已提交
1125 1126 1127 1128 1129 1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 1144
{
	if (current->active_mm == mm)
		load_cr3(swapper_pg_dir);
}
#endif

/*
 * While a process runs, Xen pins its pagetables, which means that the
 * hypervisor forces it to be read-only, and it controls all updates
 * to it.  This means that all pagetable updates have to go via the
 * hypervisor, which is moderately expensive.
 *
 * Since we're pulling the pagetable down, we switch to use init_mm,
 * unpin old process pagetable and mark it all read-write, which
 * allows further operations on it to be simple memory accesses.
 *
 * The only subtle point is that another CPU may be still using the
 * pagetable because of lazy tlb flushing.  This means we need need to
 * switch all CPUs off this pagetable before we can unpin it.
 */
1145
static void xen_exit_mmap(struct mm_struct *mm)
J
Jeremy Fitzhardinge 已提交
1146 1147
{
	get_cpu();		/* make sure we don't move around */
1148
	xen_drop_mm_ref(mm);
J
Jeremy Fitzhardinge 已提交
1149
	put_cpu();
J
Jeremy Fitzhardinge 已提交
1150

1151
	spin_lock(&mm->page_table_lock);
1152 1153

	/* pgd may not be pinned in the error exit path of execve */
1154
	if (xen_page_pinned(mm->pgd))
1155
		xen_pgd_unpin(mm);
1156

1157
	spin_unlock(&mm->page_table_lock);
J
Jeremy Fitzhardinge 已提交
1158
}
J
Jeremy Fitzhardinge 已提交
1159

1160
static void __init xen_pagetable_setup_start(pgd_t *base)
1161 1162 1163
{
}

1164 1165 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175 1176 1177
static __init void xen_mapping_pagetable_reserve(u64 start, u64 end)
{
	/* reserve the range used */
	native_pagetable_reserve(start, end);

	/* set as RW the rest */
	printk(KERN_DEBUG "xen: setting RW the range %llx - %llx\n", end,
			PFN_PHYS(pgt_buf_top));
	while (end < PFN_PHYS(pgt_buf_top)) {
		make_lowmem_page_readwrite(__va(end));
		end += PAGE_SIZE;
	}
}

1178 1179
static void xen_post_allocator_init(void);

1180
static void __init xen_pagetable_setup_done(pgd_t *base)
1181 1182
{
	xen_setup_shared_info();
1183
	xen_post_allocator_init();
1184 1185 1186 1187
}

static void xen_write_cr2(unsigned long cr2)
{
1188
	this_cpu_read(xen_vcpu)->arch.cr2 = cr2;
1189 1190 1191 1192
}

static unsigned long xen_read_cr2(void)
{
1193
	return this_cpu_read(xen_vcpu)->arch.cr2;
1194 1195 1196 1197
}

unsigned long xen_read_cr2_direct(void)
{
1198
	return this_cpu_read(xen_vcpu_info.arch.cr2);
1199 1200 1201 1202 1203 1204 1205
}

static void xen_flush_tlb(void)
{
	struct mmuext_op *op;
	struct multicall_space mcs;

1206 1207
	trace_xen_mmu_flush_tlb(0);

1208 1209 1210 1211 1212 1213 1214 1215 1216 1217 1218 1219 1220 1221 1222 1223 1224 1225
	preempt_disable();

	mcs = xen_mc_entry(sizeof(*op));

	op = mcs.args;
	op->cmd = MMUEXT_TLB_FLUSH_LOCAL;
	MULTI_mmuext_op(mcs.mc, op, 1, NULL, DOMID_SELF);

	xen_mc_issue(PARAVIRT_LAZY_MMU);

	preempt_enable();
}

static void xen_flush_tlb_single(unsigned long addr)
{
	struct mmuext_op *op;
	struct multicall_space mcs;

1226 1227
	trace_xen_mmu_flush_tlb_single(addr);

1228 1229 1230 1231 1232 1233 1234 1235 1236 1237 1238 1239 1240 1241 1242 1243 1244 1245
	preempt_disable();

	mcs = xen_mc_entry(sizeof(*op));
	op = mcs.args;
	op->cmd = MMUEXT_INVLPG_LOCAL;
	op->arg1.linear_addr = addr & PAGE_MASK;
	MULTI_mmuext_op(mcs.mc, op, 1, NULL, DOMID_SELF);

	xen_mc_issue(PARAVIRT_LAZY_MMU);

	preempt_enable();
}

static void xen_flush_tlb_others(const struct cpumask *cpus,
				 struct mm_struct *mm, unsigned long va)
{
	struct {
		struct mmuext_op op;
1246
#ifdef CONFIG_SMP
A
Andrew Jones 已提交
1247
		DECLARE_BITMAP(mask, num_processors);
1248 1249 1250
#else
		DECLARE_BITMAP(mask, NR_CPUS);
#endif
1251 1252 1253
	} *args;
	struct multicall_space mcs;

1254 1255
	trace_xen_mmu_flush_tlb_others(cpus, mm, va);

1256 1257
	if (cpumask_empty(cpus))
		return;		/* nothing to do */
1258 1259 1260 1261 1262 1263 1264 1265 1266 1267 1268 1269 1270 1271 1272 1273 1274 1275 1276 1277 1278 1279 1280

	mcs = xen_mc_entry(sizeof(*args));
	args = mcs.args;
	args->op.arg2.vcpumask = to_cpumask(args->mask);

	/* Remove us, and any offline CPUS. */
	cpumask_and(to_cpumask(args->mask), cpus, cpu_online_mask);
	cpumask_clear_cpu(smp_processor_id(), to_cpumask(args->mask));

	if (va == TLB_FLUSH_ALL) {
		args->op.cmd = MMUEXT_TLB_FLUSH_MULTI;
	} else {
		args->op.cmd = MMUEXT_INVLPG_MULTI;
		args->op.arg1.linear_addr = va;
	}

	MULTI_mmuext_op(mcs.mc, &args->op, 1, NULL, DOMID_SELF);

	xen_mc_issue(PARAVIRT_LAZY_MMU);
}

static unsigned long xen_read_cr3(void)
{
1281
	return this_cpu_read(xen_cr3);
1282 1283 1284 1285
}

static void set_current_cr3(void *v)
{
1286
	this_cpu_write(xen_current_cr3, (unsigned long)v);
1287 1288 1289 1290
}

static void __xen_write_cr3(bool kernel, unsigned long cr3)
{
1291
	struct mmuext_op op;
1292 1293
	unsigned long mfn;

1294 1295
	trace_xen_mmu_write_cr3(kernel, cr3);

1296 1297 1298 1299 1300 1301 1302
	if (cr3)
		mfn = pfn_to_mfn(PFN_DOWN(cr3));
	else
		mfn = 0;

	WARN_ON(mfn == 0 && kernel);

1303 1304
	op.cmd = kernel ? MMUEXT_NEW_BASEPTR : MMUEXT_NEW_USER_BASEPTR;
	op.arg1.mfn = mfn;
1305

1306
	xen_extend_mmuext_op(&op);
1307 1308

	if (kernel) {
1309
		this_cpu_write(xen_cr3, cr3);
1310 1311 1312 1313 1314 1315 1316 1317 1318 1319 1320 1321 1322 1323 1324

		/* Update xen_current_cr3 once the batch has actually
		   been submitted. */
		xen_mc_callback(set_current_cr3, (void *)cr3);
	}
}

static void xen_write_cr3(unsigned long cr3)
{
	BUG_ON(preemptible());

	xen_mc_batch();  /* disables interrupts */

	/* Update while interrupts are disabled, so its atomic with
	   respect to ipis */
1325
	this_cpu_write(xen_cr3, cr3);
1326 1327 1328 1329 1330 1331 1332 1333 1334 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 1363 1364 1365 1366 1367 1368 1369 1370 1371 1372 1373 1374 1375 1376 1377 1378 1379 1380 1381 1382 1383

	__xen_write_cr3(true, cr3);

#ifdef CONFIG_X86_64
	{
		pgd_t *user_pgd = xen_get_user_pgd(__va(cr3));
		if (user_pgd)
			__xen_write_cr3(false, __pa(user_pgd));
		else
			__xen_write_cr3(false, 0);
	}
#endif

	xen_mc_issue(PARAVIRT_LAZY_CPU);  /* interrupts restored */
}

static int xen_pgd_alloc(struct mm_struct *mm)
{
	pgd_t *pgd = mm->pgd;
	int ret = 0;

	BUG_ON(PagePinned(virt_to_page(pgd)));

#ifdef CONFIG_X86_64
	{
		struct page *page = virt_to_page(pgd);
		pgd_t *user_pgd;

		BUG_ON(page->private != 0);

		ret = -ENOMEM;

		user_pgd = (pgd_t *)__get_free_page(GFP_KERNEL | __GFP_ZERO);
		page->private = (unsigned long)user_pgd;

		if (user_pgd != NULL) {
			user_pgd[pgd_index(VSYSCALL_START)] =
				__pgd(__pa(level3_user_vsyscall) | _PAGE_TABLE);
			ret = 0;
		}

		BUG_ON(PagePinned(virt_to_page(xen_get_user_pgd(pgd))));
	}
#endif

	return ret;
}

static void xen_pgd_free(struct mm_struct *mm, pgd_t *pgd)
{
#ifdef CONFIG_X86_64
	pgd_t *user_pgd = xen_get_user_pgd(pgd);

	if (user_pgd)
		free_page((unsigned long)user_pgd);
#endif
}

1384
#ifdef CONFIG_X86_32
1385
static pte_t __init mask_rw_pte(pte_t *ptep, pte_t pte)
1386 1387 1388 1389 1390
{
	/* If there's an existing pte, then don't allow _PAGE_RW to be set */
	if (pte_val_ma(*ptep) & _PAGE_PRESENT)
		pte = __pte_ma(((pte_val_ma(*ptep) & _PAGE_RW) | ~_PAGE_RW) &
			       pte_val_ma(pte));
1391 1392 1393 1394

	return pte;
}
#else /* CONFIG_X86_64 */
1395
static pte_t __init mask_rw_pte(pte_t *ptep, pte_t pte)
1396 1397
{
	unsigned long pfn = pte_pfn(pte);
1398 1399 1400 1401

	/*
	 * If the new pfn is within the range of the newly allocated
	 * kernel pagetable, and it isn't being mapped into an
1402 1403
	 * early_ioremap fixmap slot as a freshly allocated page, make sure
	 * it is RO.
1404
	 */
1405
	if (((!is_early_ioremap_ptep(ptep) &&
1406
			pfn >= pgt_buf_start && pfn < pgt_buf_top)) ||
1407
			(is_early_ioremap_ptep(ptep) && pfn != (pgt_buf_end - 1)))
1408
		pte = pte_wrprotect(pte);
1409 1410 1411

	return pte;
}
1412
#endif /* CONFIG_X86_64 */
1413 1414 1415

/* Init-time set_pte while constructing initial pagetables, which
   doesn't allow RO pagetable pages to be remapped RW */
1416
static void __init xen_set_pte_init(pte_t *ptep, pte_t pte)
1417 1418 1419 1420 1421
{
	pte = mask_rw_pte(ptep, pte);

	xen_set_pte(ptep, pte);
}
1422

1423 1424 1425 1426 1427 1428 1429 1430 1431
static void pin_pagetable_pfn(unsigned cmd, unsigned long pfn)
{
	struct mmuext_op op;
	op.cmd = cmd;
	op.arg1.mfn = pfn_to_mfn(pfn);
	if (HYPERVISOR_mmuext_op(&op, 1, NULL, DOMID_SELF))
		BUG();
}

1432 1433
/* Early in boot, while setting up the initial pagetable, assume
   everything is pinned. */
1434
static void __init xen_alloc_pte_init(struct mm_struct *mm, unsigned long pfn)
1435
{
1436 1437 1438 1439 1440 1441 1442 1443
#ifdef CONFIG_FLATMEM
	BUG_ON(mem_map);	/* should only be used early */
#endif
	make_lowmem_page_readonly(__va(PFN_PHYS(pfn)));
	pin_pagetable_pfn(MMUEXT_PIN_L1_TABLE, pfn);
}

/* Used for pmd and pud */
1444
static void __init xen_alloc_pmd_init(struct mm_struct *mm, unsigned long pfn)
1445
{
1446 1447 1448 1449 1450 1451 1452 1453
#ifdef CONFIG_FLATMEM
	BUG_ON(mem_map);	/* should only be used early */
#endif
	make_lowmem_page_readonly(__va(PFN_PHYS(pfn)));
}

/* Early release_pte assumes that all pts are pinned, since there's
   only init_mm and anything attached to that is pinned. */
1454
static void __init xen_release_pte_init(unsigned long pfn)
1455
{
1456
	pin_pagetable_pfn(MMUEXT_UNPIN_TABLE, pfn);
1457 1458 1459
	make_lowmem_page_readwrite(__va(PFN_PHYS(pfn)));
}

1460
static void __init xen_release_pmd_init(unsigned long pfn)
1461
{
1462
	make_lowmem_page_readwrite(__va(PFN_PHYS(pfn)));
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
static inline void __pin_pagetable_pfn(unsigned cmd, unsigned long pfn)
{
	struct multicall_space mcs;
	struct mmuext_op *op;

	mcs = __xen_mc_entry(sizeof(*op));
	op = mcs.args;
	op->cmd = cmd;
	op->arg1.mfn = pfn_to_mfn(pfn);

	MULTI_mmuext_op(mcs.mc, mcs.args, 1, NULL, DOMID_SELF);
}

static inline void __set_pfn_prot(unsigned long pfn, pgprot_t prot)
{
	struct multicall_space mcs;
	unsigned long addr = (unsigned long)__va(pfn << PAGE_SHIFT);

	mcs = __xen_mc_entry(0);
	MULTI_update_va_mapping(mcs.mc, (unsigned long)addr,
				pfn_pte(pfn, prot), 0);
}

1488 1489
/* This needs to make sure the new pte page is pinned iff its being
   attached to a pinned pagetable. */
1490 1491
static inline void xen_alloc_ptpage(struct mm_struct *mm, unsigned long pfn,
				    unsigned level)
1492
{
1493 1494
	bool pinned = PagePinned(virt_to_page(mm->pgd));

1495
	trace_xen_mmu_alloc_ptpage(mm, pfn, level, pinned);
1496

1497
	if (pinned) {
1498
		struct page *page = pfn_to_page(pfn);
1499 1500 1501 1502

		SetPagePinned(page);

		if (!PageHighMem(page)) {
1503 1504 1505 1506
			xen_mc_batch();

			__set_pfn_prot(pfn, PAGE_KERNEL_RO);

1507
			if (level == PT_PTE && USE_SPLIT_PTLOCKS)
1508 1509 1510
				__pin_pagetable_pfn(MMUEXT_PIN_L1_TABLE, pfn);

			xen_mc_issue(PARAVIRT_LAZY_MMU);
1511 1512 1513 1514 1515 1516 1517 1518 1519 1520 1521 1522 1523 1524 1525 1526 1527 1528 1529
		} else {
			/* make sure there are no stray mappings of
			   this page */
			kmap_flush_unused();
		}
	}
}

static void xen_alloc_pte(struct mm_struct *mm, unsigned long pfn)
{
	xen_alloc_ptpage(mm, pfn, PT_PTE);
}

static void xen_alloc_pmd(struct mm_struct *mm, unsigned long pfn)
{
	xen_alloc_ptpage(mm, pfn, PT_PMD);
}

/* This should never happen until we're OK to use struct page */
1530
static inline void xen_release_ptpage(unsigned long pfn, unsigned level)
1531 1532
{
	struct page *page = pfn_to_page(pfn);
1533
	bool pinned = PagePinned(page);
1534

1535
	trace_xen_mmu_release_ptpage(pfn, level, pinned);
1536

1537
	if (pinned) {
1538
		if (!PageHighMem(page)) {
1539 1540
			xen_mc_batch();

1541
			if (level == PT_PTE && USE_SPLIT_PTLOCKS)
1542 1543 1544 1545 1546
				__pin_pagetable_pfn(MMUEXT_UNPIN_TABLE, pfn);

			__set_pfn_prot(pfn, PAGE_KERNEL);

			xen_mc_issue(PARAVIRT_LAZY_MMU);
1547 1548 1549 1550 1551 1552 1553 1554 1555 1556 1557 1558 1559 1560 1561 1562 1563 1564 1565 1566 1567 1568 1569 1570 1571 1572 1573 1574 1575 1576 1577 1578 1579 1580 1581 1582 1583 1584 1585 1586 1587 1588 1589 1590 1591 1592 1593 1594 1595 1596 1597 1598 1599 1600 1601 1602 1603 1604 1605 1606 1607 1608 1609 1610 1611 1612 1613 1614 1615 1616
		}
		ClearPagePinned(page);
	}
}

static void xen_release_pte(unsigned long pfn)
{
	xen_release_ptpage(pfn, PT_PTE);
}

static void xen_release_pmd(unsigned long pfn)
{
	xen_release_ptpage(pfn, PT_PMD);
}

#if PAGETABLE_LEVELS == 4
static void xen_alloc_pud(struct mm_struct *mm, unsigned long pfn)
{
	xen_alloc_ptpage(mm, pfn, PT_PUD);
}

static void xen_release_pud(unsigned long pfn)
{
	xen_release_ptpage(pfn, PT_PUD);
}
#endif

void __init xen_reserve_top(void)
{
#ifdef CONFIG_X86_32
	unsigned long top = HYPERVISOR_VIRT_START;
	struct xen_platform_parameters pp;

	if (HYPERVISOR_xen_version(XENVER_platform_parameters, &pp) == 0)
		top = pp.virt_start;

	reserve_top_address(-top);
#endif	/* CONFIG_X86_32 */
}

/*
 * Like __va(), but returns address in the kernel mapping (which is
 * all we have until the physical memory mapping has been set up.
 */
static void *__ka(phys_addr_t paddr)
{
#ifdef CONFIG_X86_64
	return (void *)(paddr + __START_KERNEL_map);
#else
	return __va(paddr);
#endif
}

/* Convert a machine address to physical address */
static unsigned long m2p(phys_addr_t maddr)
{
	phys_addr_t paddr;

	maddr &= PTE_PFN_MASK;
	paddr = mfn_to_pfn(maddr >> PAGE_SHIFT) << PAGE_SHIFT;

	return paddr;
}

/* Convert a machine address to kernel virtual */
static void *m2v(phys_addr_t maddr)
{
	return __ka(m2p(maddr));
}

1617
/* Set the page permissions on an identity-mapped pages */
1618 1619 1620 1621 1622 1623 1624 1625 1626
static void set_page_prot(void *addr, pgprot_t prot)
{
	unsigned long pfn = __pa(addr) >> PAGE_SHIFT;
	pte_t pte = pfn_pte(pfn, prot);

	if (HYPERVISOR_update_va_mapping((unsigned long)addr, pte, 0))
		BUG();
}

1627
static void __init xen_map_identity_early(pmd_t *pmd, unsigned long max_pfn)
1628 1629 1630 1631 1632
{
	unsigned pmdidx, pteidx;
	unsigned ident_pte;
	unsigned long pfn;

1633 1634 1635
	level1_ident_pgt = extend_brk(sizeof(pte_t) * LEVEL1_IDENT_ENTRIES,
				      PAGE_SIZE);

1636 1637 1638 1639 1640 1641 1642 1643 1644 1645
	ident_pte = 0;
	pfn = 0;
	for (pmdidx = 0; pmdidx < PTRS_PER_PMD && pfn < max_pfn; pmdidx++) {
		pte_t *pte_page;

		/* Reuse or allocate a page of ptes */
		if (pmd_present(pmd[pmdidx]))
			pte_page = m2v(pmd[pmdidx].pmd);
		else {
			/* Check for free pte pages */
1646
			if (ident_pte == LEVEL1_IDENT_ENTRIES)
1647 1648 1649 1650 1651 1652 1653 1654 1655 1656 1657 1658
				break;

			pte_page = &level1_ident_pgt[ident_pte];
			ident_pte += PTRS_PER_PTE;

			pmd[pmdidx] = __pmd(__pa(pte_page) | _PAGE_TABLE);
		}

		/* Install mappings */
		for (pteidx = 0; pteidx < PTRS_PER_PTE; pteidx++, pfn++) {
			pte_t pte;

1659 1660 1661 1662 1663
#ifdef CONFIG_X86_32
			if (pfn > max_pfn_mapped)
				max_pfn_mapped = pfn;
#endif

1664 1665 1666 1667 1668 1669 1670 1671 1672 1673 1674 1675 1676 1677
			if (!pte_none(pte_page[pteidx]))
				continue;

			pte = pfn_pte(pfn, PAGE_KERNEL_EXEC);
			pte_page[pteidx] = pte;
		}
	}

	for (pteidx = 0; pteidx < ident_pte; pteidx += PTRS_PER_PTE)
		set_page_prot(&level1_ident_pgt[pteidx], PAGE_KERNEL_RO);

	set_page_prot(pmd, PAGE_KERNEL_RO);
}

1678 1679 1680 1681 1682 1683
void __init xen_setup_machphys_mapping(void)
{
	struct xen_machphys_mapping mapping;

	if (HYPERVISOR_memory_op(XENMEM_machphys_mapping, &mapping) == 0) {
		machine_to_phys_mapping = (unsigned long *)mapping.v_start;
1684
		machine_to_phys_nr = mapping.max_mfn + 1;
1685
	} else {
1686
		machine_to_phys_nr = MACH2PHYS_NR_ENTRIES;
1687
	}
1688
#ifdef CONFIG_X86_32
1689 1690
	WARN_ON((machine_to_phys_mapping + (machine_to_phys_nr - 1))
		< machine_to_phys_mapping);
1691
#endif
1692 1693
}

1694 1695 1696 1697 1698 1699 1700 1701 1702 1703 1704 1705 1706
#ifdef CONFIG_X86_64
static void convert_pfn_mfn(void *v)
{
	pte_t *pte = v;
	int i;

	/* All levels are converted the same way, so just treat them
	   as ptes. */
	for (i = 0; i < PTRS_PER_PTE; i++)
		pte[i] = xen_make_pte(pte[i].pte);
}

/*
L
Lucas De Marchi 已提交
1707
 * Set up the initial kernel pagetable.
1708 1709 1710 1711 1712 1713 1714 1715 1716
 *
 * We can construct this by grafting the Xen provided pagetable into
 * head_64.S's preconstructed pagetables.  We copy the Xen L2's into
 * level2_ident_pgt, level2_kernel_pgt and level2_fixmap_pgt.  This
 * means that only the kernel has a physical mapping to start with -
 * but that's enough to get __va working.  We need to fill in the rest
 * of the physical mapping once some sort of allocator has been set
 * up.
 */
1717
pgd_t * __init xen_setup_kernel_pagetable(pgd_t *pgd,
1718 1719 1720 1721 1722
					 unsigned long max_pfn)
{
	pud_t *l3;
	pmd_t *l2;

1723 1724 1725 1726 1727 1728
	/* max_pfn_mapped is the last pfn mapped in the initial memory
	 * mappings. Considering that on Xen after the kernel mappings we
	 * have the mappings of some pages that don't exist in pfn space, we
	 * set max_pfn_mapped to the last real pfn mapped. */
	max_pfn_mapped = PFN_DOWN(__pa(xen_start_info->mfn_list));

1729 1730 1731 1732 1733 1734 1735 1736 1737 1738 1739 1740 1741 1742 1743 1744 1745 1746 1747 1748 1749 1750 1751 1752 1753 1754 1755 1756 1757 1758 1759 1760 1761 1762 1763 1764 1765 1766 1767 1768 1769 1770 1771 1772 1773 1774 1775 1776
	/* Zap identity mapping */
	init_level4_pgt[0] = __pgd(0);

	/* Pre-constructed entries are in pfn, so convert to mfn */
	convert_pfn_mfn(init_level4_pgt);
	convert_pfn_mfn(level3_ident_pgt);
	convert_pfn_mfn(level3_kernel_pgt);

	l3 = m2v(pgd[pgd_index(__START_KERNEL_map)].pgd);
	l2 = m2v(l3[pud_index(__START_KERNEL_map)].pud);

	memcpy(level2_ident_pgt, l2, sizeof(pmd_t) * PTRS_PER_PMD);
	memcpy(level2_kernel_pgt, l2, sizeof(pmd_t) * PTRS_PER_PMD);

	l3 = m2v(pgd[pgd_index(__START_KERNEL_map + PMD_SIZE)].pgd);
	l2 = m2v(l3[pud_index(__START_KERNEL_map + PMD_SIZE)].pud);
	memcpy(level2_fixmap_pgt, l2, sizeof(pmd_t) * PTRS_PER_PMD);

	/* Set up identity map */
	xen_map_identity_early(level2_ident_pgt, max_pfn);

	/* Make pagetable pieces RO */
	set_page_prot(init_level4_pgt, PAGE_KERNEL_RO);
	set_page_prot(level3_ident_pgt, PAGE_KERNEL_RO);
	set_page_prot(level3_kernel_pgt, PAGE_KERNEL_RO);
	set_page_prot(level3_user_vsyscall, PAGE_KERNEL_RO);
	set_page_prot(level2_kernel_pgt, PAGE_KERNEL_RO);
	set_page_prot(level2_fixmap_pgt, PAGE_KERNEL_RO);

	/* Pin down new L4 */
	pin_pagetable_pfn(MMUEXT_PIN_L4_TABLE,
			  PFN_DOWN(__pa_symbol(init_level4_pgt)));

	/* Unpin Xen-provided one */
	pin_pagetable_pfn(MMUEXT_UNPIN_TABLE, PFN_DOWN(__pa(pgd)));

	/* Switch over */
	pgd = init_level4_pgt;

	/*
	 * At this stage there can be no user pgd, and no page
	 * structure to attach it to, so make sure we just set kernel
	 * pgd.
	 */
	xen_mc_batch();
	__xen_write_cr3(true, __pa(pgd));
	xen_mc_issue(PARAVIRT_LAZY_CPU);

1777 1778
	memblock_reserve(__pa(xen_start_info->pt_base),
			 xen_start_info->nr_pt_frames * PAGE_SIZE);
1779 1780 1781 1782

	return pgd;
}
#else	/* !CONFIG_X86_64 */
1783 1784 1785
static RESERVE_BRK_ARRAY(pmd_t, initial_kernel_pmd, PTRS_PER_PMD);
static RESERVE_BRK_ARRAY(pmd_t, swapper_kernel_pmd, PTRS_PER_PMD);

1786
static void __init xen_write_cr3_init(unsigned long cr3)
1787 1788 1789 1790 1791 1792 1793 1794 1795 1796 1797 1798 1799 1800 1801 1802 1803 1804 1805 1806 1807 1808 1809 1810 1811 1812 1813 1814 1815 1816 1817 1818 1819 1820 1821
{
	unsigned long pfn = PFN_DOWN(__pa(swapper_pg_dir));

	BUG_ON(read_cr3() != __pa(initial_page_table));
	BUG_ON(cr3 != __pa(swapper_pg_dir));

	/*
	 * We are switching to swapper_pg_dir for the first time (from
	 * initial_page_table) and therefore need to mark that page
	 * read-only and then pin it.
	 *
	 * Xen disallows sharing of kernel PMDs for PAE
	 * guests. Therefore we must copy the kernel PMD from
	 * initial_page_table into a new kernel PMD to be used in
	 * swapper_pg_dir.
	 */
	swapper_kernel_pmd =
		extend_brk(sizeof(pmd_t) * PTRS_PER_PMD, PAGE_SIZE);
	memcpy(swapper_kernel_pmd, initial_kernel_pmd,
	       sizeof(pmd_t) * PTRS_PER_PMD);
	swapper_pg_dir[KERNEL_PGD_BOUNDARY] =
		__pgd(__pa(swapper_kernel_pmd) | _PAGE_PRESENT);
	set_page_prot(swapper_kernel_pmd, PAGE_KERNEL_RO);

	set_page_prot(swapper_pg_dir, PAGE_KERNEL_RO);
	xen_write_cr3(cr3);
	pin_pagetable_pfn(MMUEXT_PIN_L3_TABLE, pfn);

	pin_pagetable_pfn(MMUEXT_UNPIN_TABLE,
			  PFN_DOWN(__pa(initial_page_table)));
	set_page_prot(initial_page_table, PAGE_KERNEL);
	set_page_prot(initial_kernel_pmd, PAGE_KERNEL);

	pv_mmu_ops.write_cr3 = &xen_write_cr3;
}
1822

1823
pgd_t * __init xen_setup_kernel_pagetable(pgd_t *pgd,
1824 1825 1826 1827
					 unsigned long max_pfn)
{
	pmd_t *kernel_pmd;

1828 1829
	initial_kernel_pmd =
		extend_brk(sizeof(pmd_t) * PTRS_PER_PMD, PAGE_SIZE);
1830

1831 1832 1833
	max_pfn_mapped = PFN_DOWN(__pa(xen_start_info->pt_base) +
				  xen_start_info->nr_pt_frames * PAGE_SIZE +
				  512*1024);
1834 1835

	kernel_pmd = m2v(pgd[KERNEL_PGD_BOUNDARY].pgd);
1836
	memcpy(initial_kernel_pmd, kernel_pmd, sizeof(pmd_t) * PTRS_PER_PMD);
1837

1838
	xen_map_identity_early(initial_kernel_pmd, max_pfn);
1839

1840 1841 1842
	memcpy(initial_page_table, pgd, sizeof(pgd_t) * PTRS_PER_PGD);
	initial_page_table[KERNEL_PGD_BOUNDARY] =
		__pgd(__pa(initial_kernel_pmd) | _PAGE_PRESENT);
1843

1844 1845
	set_page_prot(initial_kernel_pmd, PAGE_KERNEL_RO);
	set_page_prot(initial_page_table, PAGE_KERNEL_RO);
1846 1847 1848 1849
	set_page_prot(empty_zero_page, PAGE_KERNEL_RO);

	pin_pagetable_pfn(MMUEXT_UNPIN_TABLE, PFN_DOWN(__pa(pgd)));

1850 1851 1852
	pin_pagetable_pfn(MMUEXT_PIN_L3_TABLE,
			  PFN_DOWN(__pa(initial_page_table)));
	xen_write_cr3(__pa(initial_page_table));
1853

1854
	memblock_reserve(__pa(xen_start_info->pt_base),
1855
			 xen_start_info->nr_pt_frames * PAGE_SIZE);
1856

1857
	return initial_page_table;
1858 1859 1860
}
#endif	/* CONFIG_X86_64 */

1861
static unsigned char dummy_mapping[PAGE_SIZE] __page_aligned_bss;
1862
static unsigned char fake_ioapic_mapping[PAGE_SIZE] __page_aligned_bss;
1863

1864
static void xen_set_fixmap(unsigned idx, phys_addr_t phys, pgprot_t prot)
1865 1866 1867 1868 1869 1870 1871 1872 1873 1874 1875 1876 1877 1878 1879 1880 1881 1882
{
	pte_t pte;

	phys >>= PAGE_SHIFT;

	switch (idx) {
	case FIX_BTMAP_END ... FIX_BTMAP_BEGIN:
#ifdef CONFIG_X86_F00F_BUG
	case FIX_F00F_IDT:
#endif
#ifdef CONFIG_X86_32
	case FIX_WP_TEST:
	case FIX_VDSO:
# ifdef CONFIG_HIGHMEM
	case FIX_KMAP_BEGIN ... FIX_KMAP_END:
# endif
#else
	case VSYSCALL_LAST_PAGE ... VSYSCALL_FIRST_PAGE:
1883
	case VVAR_PAGE:
1884
#endif
1885 1886 1887
	case FIX_TEXT_POKE0:
	case FIX_TEXT_POKE1:
		/* All local page mappings */
1888 1889 1890
		pte = pfn_pte(phys, prot);
		break;

1891 1892 1893 1894 1895 1896 1897 1898 1899 1900 1901 1902
#ifdef CONFIG_X86_LOCAL_APIC
	case FIX_APIC_BASE:	/* maps dummy local APIC */
		pte = pfn_pte(PFN_DOWN(__pa(dummy_mapping)), PAGE_KERNEL);
		break;
#endif

#ifdef CONFIG_X86_IO_APIC
	case FIX_IO_APIC_BASE_0 ... FIX_IO_APIC_BASE_END:
		/*
		 * We just don't map the IO APIC - all access is via
		 * hypercalls.  Keep the address in the pte for reference.
		 */
1903
		pte = pfn_pte(PFN_DOWN(__pa(fake_ioapic_mapping)), PAGE_KERNEL);
1904 1905 1906
		break;
#endif

1907 1908 1909
	case FIX_PARAVIRT_BOOTMAP:
		/* This is an MFN, but it isn't an IO mapping from the
		   IO domain */
1910 1911
		pte = mfn_pte(phys, prot);
		break;
1912 1913 1914 1915 1916

	default:
		/* By default, set_fixmap is used for hardware mappings */
		pte = mfn_pte(phys, __pgprot(pgprot_val(prot) | _PAGE_IOMAP));
		break;
1917 1918 1919 1920 1921 1922 1923
	}

	__native_set_fixmap(idx, pte);

#ifdef CONFIG_X86_64
	/* Replicate changes to map the vsyscall page into the user
	   pagetable vsyscall mapping. */
1924 1925
	if ((idx >= VSYSCALL_LAST_PAGE && idx <= VSYSCALL_FIRST_PAGE) ||
	    idx == VVAR_PAGE) {
1926 1927 1928 1929 1930 1931
		unsigned long vaddr = __fix_to_virt(idx);
		set_pte_vaddr_pud(level3_user_vsyscall, vaddr, pte);
	}
#endif
}

1932
void __init xen_ident_map_ISA(void)
1933 1934 1935 1936 1937 1938 1939 1940 1941 1942 1943 1944 1945 1946 1947 1948 1949 1950 1951 1952 1953 1954
{
	unsigned long pa;

	/*
	 * If we're dom0, then linear map the ISA machine addresses into
	 * the kernel's address space.
	 */
	if (!xen_initial_domain())
		return;

	xen_raw_printk("Xen: setup ISA identity maps\n");

	for (pa = ISA_START_ADDRESS; pa < ISA_END_ADDRESS; pa += PAGE_SIZE) {
		pte_t pte = mfn_pte(PFN_DOWN(pa), PAGE_KERNEL_IO);

		if (HYPERVISOR_update_va_mapping(PAGE_OFFSET + pa, pte, 0))
			BUG();
	}

	xen_flush_tlb();
}

1955
static void __init xen_post_allocator_init(void)
1956 1957 1958 1959 1960 1961 1962 1963 1964 1965 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980
{
	pv_mmu_ops.set_pte = xen_set_pte;
	pv_mmu_ops.set_pmd = xen_set_pmd;
	pv_mmu_ops.set_pud = xen_set_pud;
#if PAGETABLE_LEVELS == 4
	pv_mmu_ops.set_pgd = xen_set_pgd;
#endif

	/* This will work as long as patching hasn't happened yet
	   (which it hasn't) */
	pv_mmu_ops.alloc_pte = xen_alloc_pte;
	pv_mmu_ops.alloc_pmd = xen_alloc_pmd;
	pv_mmu_ops.release_pte = xen_release_pte;
	pv_mmu_ops.release_pmd = xen_release_pmd;
#if PAGETABLE_LEVELS == 4
	pv_mmu_ops.alloc_pud = xen_alloc_pud;
	pv_mmu_ops.release_pud = xen_release_pud;
#endif

#ifdef CONFIG_X86_64
	SetPagePinned(virt_to_page(level3_user_vsyscall));
#endif
	xen_mark_init_mm_pinned();
}

1981 1982
static void xen_leave_lazy_mmu(void)
{
1983
	preempt_disable();
1984 1985
	xen_mc_flush();
	paravirt_leave_lazy_mmu();
1986
	preempt_enable();
1987
}
1988

1989
static const struct pv_mmu_ops xen_mmu_ops __initconst = {
1990 1991 1992 1993
	.read_cr2 = xen_read_cr2,
	.write_cr2 = xen_write_cr2,

	.read_cr3 = xen_read_cr3,
1994 1995 1996
#ifdef CONFIG_X86_32
	.write_cr3 = xen_write_cr3_init,
#else
1997
	.write_cr3 = xen_write_cr3,
1998
#endif
1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012

	.flush_tlb_user = xen_flush_tlb,
	.flush_tlb_kernel = xen_flush_tlb,
	.flush_tlb_single = xen_flush_tlb_single,
	.flush_tlb_others = xen_flush_tlb_others,

	.pte_update = paravirt_nop,
	.pte_update_defer = paravirt_nop,

	.pgd_alloc = xen_pgd_alloc,
	.pgd_free = xen_pgd_free,

	.alloc_pte = xen_alloc_pte_init,
	.release_pte = xen_release_pte_init,
2013 2014
	.alloc_pmd = xen_alloc_pmd_init,
	.release_pmd = xen_release_pmd_init,
2015 2016 2017 2018 2019 2020 2021 2022

	.set_pte = xen_set_pte_init,
	.set_pte_at = xen_set_pte_at,
	.set_pmd = xen_set_pmd_hyper,

	.ptep_modify_prot_start = __ptep_modify_prot_start,
	.ptep_modify_prot_commit = __ptep_modify_prot_commit,

2023 2024
	.pte_val = PV_CALLEE_SAVE(xen_pte_val),
	.pgd_val = PV_CALLEE_SAVE(xen_pgd_val),
2025

2026 2027
	.make_pte = PV_CALLEE_SAVE(xen_make_pte),
	.make_pgd = PV_CALLEE_SAVE(xen_make_pgd),
2028 2029 2030 2031 2032 2033 2034 2035

#ifdef CONFIG_X86_PAE
	.set_pte_atomic = xen_set_pte_atomic,
	.pte_clear = xen_pte_clear,
	.pmd_clear = xen_pmd_clear,
#endif	/* CONFIG_X86_PAE */
	.set_pud = xen_set_pud_hyper,

2036 2037
	.make_pmd = PV_CALLEE_SAVE(xen_make_pmd),
	.pmd_val = PV_CALLEE_SAVE(xen_pmd_val),
2038 2039

#if PAGETABLE_LEVELS == 4
2040 2041
	.pud_val = PV_CALLEE_SAVE(xen_pud_val),
	.make_pud = PV_CALLEE_SAVE(xen_make_pud),
2042 2043
	.set_pgd = xen_set_pgd_hyper,

2044 2045
	.alloc_pud = xen_alloc_pmd_init,
	.release_pud = xen_release_pmd_init,
2046 2047 2048 2049 2050 2051 2052 2053
#endif	/* PAGETABLE_LEVELS == 4 */

	.activate_mm = xen_activate_mm,
	.dup_mmap = xen_dup_mmap,
	.exit_mmap = xen_exit_mmap,

	.lazy_mode = {
		.enter = paravirt_enter_lazy_mmu,
2054
		.leave = xen_leave_lazy_mmu,
2055 2056 2057 2058 2059
	},

	.set_fixmap = xen_set_fixmap,
};

2060 2061
void __init xen_init_mmu_ops(void)
{
2062
	x86_init.mapping.pagetable_reserve = xen_mapping_pagetable_reserve;
2063 2064 2065
	x86_init.paging.pagetable_setup_start = xen_pagetable_setup_start;
	x86_init.paging.pagetable_setup_done = xen_pagetable_setup_done;
	pv_mmu_ops = xen_mmu_ops;
2066

2067
	memset(dummy_mapping, 0xff, PAGE_SIZE);
2068
	memset(fake_ioapic_mapping, 0xfd, PAGE_SIZE);
2069
}
2070

2071 2072 2073 2074 2075 2076 2077 2078 2079 2080 2081 2082 2083 2084 2085 2086 2087 2088 2089 2090
/* Protected by xen_reservation_lock. */
#define MAX_CONTIG_ORDER 9 /* 2MB */
static unsigned long discontig_frames[1<<MAX_CONTIG_ORDER];

#define VOID_PTE (mfn_pte(0, __pgprot(0)))
static void xen_zap_pfn_range(unsigned long vaddr, unsigned int order,
				unsigned long *in_frames,
				unsigned long *out_frames)
{
	int i;
	struct multicall_space mcs;

	xen_mc_batch();
	for (i = 0; i < (1UL<<order); i++, vaddr += PAGE_SIZE) {
		mcs = __xen_mc_entry(0);

		if (in_frames)
			in_frames[i] = virt_to_mfn(vaddr);

		MULTI_update_va_mapping(mcs.mc, vaddr, VOID_PTE, 0);
2091
		__set_phys_to_machine(virt_to_pfn(vaddr), INVALID_P2M_ENTRY);
2092 2093 2094 2095 2096 2097 2098 2099 2100 2101 2102 2103 2104 2105 2106 2107 2108 2109 2110 2111 2112 2113 2114 2115 2116 2117 2118 2119 2120 2121 2122 2123 2124 2125 2126 2127 2128 2129 2130 2131 2132 2133 2134 2135 2136 2137 2138 2139 2140 2141 2142 2143 2144 2145 2146 2147 2148 2149 2150 2151 2152 2153 2154 2155 2156 2157 2158 2159 2160 2161 2162 2163 2164 2165 2166 2167 2168 2169 2170 2171 2172 2173 2174 2175 2176 2177 2178 2179 2180 2181 2182 2183 2184 2185 2186 2187 2188 2189 2190 2191 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

		if (out_frames)
			out_frames[i] = virt_to_pfn(vaddr);
	}
	xen_mc_issue(0);
}

/*
 * Update the pfn-to-mfn mappings for a virtual address range, either to
 * point to an array of mfns, or contiguously from a single starting
 * mfn.
 */
static void xen_remap_exchanged_ptes(unsigned long vaddr, int order,
				     unsigned long *mfns,
				     unsigned long first_mfn)
{
	unsigned i, limit;
	unsigned long mfn;

	xen_mc_batch();

	limit = 1u << order;
	for (i = 0; i < limit; i++, vaddr += PAGE_SIZE) {
		struct multicall_space mcs;
		unsigned flags;

		mcs = __xen_mc_entry(0);
		if (mfns)
			mfn = mfns[i];
		else
			mfn = first_mfn + i;

		if (i < (limit - 1))
			flags = 0;
		else {
			if (order == 0)
				flags = UVMF_INVLPG | UVMF_ALL;
			else
				flags = UVMF_TLB_FLUSH | UVMF_ALL;
		}

		MULTI_update_va_mapping(mcs.mc, vaddr,
				mfn_pte(mfn, PAGE_KERNEL), flags);

		set_phys_to_machine(virt_to_pfn(vaddr), mfn);
	}

	xen_mc_issue(0);
}

/*
 * Perform the hypercall to exchange a region of our pfns to point to
 * memory with the required contiguous alignment.  Takes the pfns as
 * input, and populates mfns as output.
 *
 * Returns a success code indicating whether the hypervisor was able to
 * satisfy the request or not.
 */
static int xen_exchange_memory(unsigned long extents_in, unsigned int order_in,
			       unsigned long *pfns_in,
			       unsigned long extents_out,
			       unsigned int order_out,
			       unsigned long *mfns_out,
			       unsigned int address_bits)
{
	long rc;
	int success;

	struct xen_memory_exchange exchange = {
		.in = {
			.nr_extents   = extents_in,
			.extent_order = order_in,
			.extent_start = pfns_in,
			.domid        = DOMID_SELF
		},
		.out = {
			.nr_extents   = extents_out,
			.extent_order = order_out,
			.extent_start = mfns_out,
			.address_bits = address_bits,
			.domid        = DOMID_SELF
		}
	};

	BUG_ON(extents_in << order_in != extents_out << order_out);

	rc = HYPERVISOR_memory_op(XENMEM_exchange, &exchange);
	success = (exchange.nr_exchanged == extents_in);

	BUG_ON(!success && ((exchange.nr_exchanged != 0) || (rc == 0)));
	BUG_ON(success && (rc != 0));

	return success;
}

int xen_create_contiguous_region(unsigned long vstart, unsigned int order,
				 unsigned int address_bits)
{
	unsigned long *in_frames = discontig_frames, out_frame;
	unsigned long  flags;
	int            success;

	/*
	 * Currently an auto-translated guest will not perform I/O, nor will
	 * it require PAE page directories below 4GB. Therefore any calls to
	 * this function are redundant and can be ignored.
	 */

	if (xen_feature(XENFEAT_auto_translated_physmap))
		return 0;

	if (unlikely(order > MAX_CONTIG_ORDER))
		return -ENOMEM;

	memset((void *) vstart, 0, PAGE_SIZE << order);

	spin_lock_irqsave(&xen_reservation_lock, flags);

	/* 1. Zap current PTEs, remembering MFNs. */
	xen_zap_pfn_range(vstart, order, in_frames, NULL);

	/* 2. Get a new contiguous memory extent. */
	out_frame = virt_to_pfn(vstart);
	success = xen_exchange_memory(1UL << order, 0, in_frames,
				      1, order, &out_frame,
				      address_bits);

	/* 3. Map the new extent in place of old pages. */
	if (success)
		xen_remap_exchanged_ptes(vstart, order, NULL, out_frame);
	else
		xen_remap_exchanged_ptes(vstart, order, in_frames, 0);

	spin_unlock_irqrestore(&xen_reservation_lock, flags);

	return success ? 0 : -ENOMEM;
}
EXPORT_SYMBOL_GPL(xen_create_contiguous_region);

void xen_destroy_contiguous_region(unsigned long vstart, unsigned int order)
{
	unsigned long *out_frames = discontig_frames, in_frame;
	unsigned long  flags;
	int success;

	if (xen_feature(XENFEAT_auto_translated_physmap))
		return;

	if (unlikely(order > MAX_CONTIG_ORDER))
		return;

	memset((void *) vstart, 0, PAGE_SIZE << order);

	spin_lock_irqsave(&xen_reservation_lock, flags);

	/* 1. Find start MFN of contiguous extent. */
	in_frame = virt_to_mfn(vstart);

	/* 2. Zap current PTEs. */
	xen_zap_pfn_range(vstart, order, NULL, out_frames);

	/* 3. Do the exchange for non-contiguous MFNs. */
	success = xen_exchange_memory(1, order, &in_frame, 1UL << order,
					0, out_frames, 0);

	/* 4. Map new pages in place of old pages. */
	if (success)
		xen_remap_exchanged_ptes(vstart, order, out_frames, 0);
	else
		xen_remap_exchanged_ptes(vstart, order, NULL, in_frame);

	spin_unlock_irqrestore(&xen_reservation_lock, flags);
2264
}
2265
EXPORT_SYMBOL_GPL(xen_destroy_contiguous_region);
2266

2267
#ifdef CONFIG_XEN_PVHVM
2268 2269 2270 2271 2272 2273 2274 2275 2276 2277 2278 2279 2280 2281 2282 2283 2284 2285 2286 2287 2288 2289 2290 2291 2292 2293 2294 2295 2296 2297 2298
static void xen_hvm_exit_mmap(struct mm_struct *mm)
{
	struct xen_hvm_pagetable_dying a;
	int rc;

	a.domid = DOMID_SELF;
	a.gpa = __pa(mm->pgd);
	rc = HYPERVISOR_hvm_op(HVMOP_pagetable_dying, &a);
	WARN_ON_ONCE(rc < 0);
}

static int is_pagetable_dying_supported(void)
{
	struct xen_hvm_pagetable_dying a;
	int rc = 0;

	a.domid = DOMID_SELF;
	a.gpa = 0x00;
	rc = HYPERVISOR_hvm_op(HVMOP_pagetable_dying, &a);
	if (rc < 0) {
		printk(KERN_DEBUG "HVMOP_pagetable_dying not supported\n");
		return 0;
	}
	return 1;
}

void __init xen_hvm_init_mmu_ops(void)
{
	if (is_pagetable_dying_supported())
		pv_mmu_ops.exit_mmap = xen_hvm_exit_mmap;
}
2299
#endif
2300

2301 2302 2303 2304 2305 2306 2307 2308 2309 2310 2311 2312 2313 2314
#define REMAP_BATCH_SIZE 16

struct remap_data {
	unsigned long mfn;
	pgprot_t prot;
	struct mmu_update *mmu_update;
};

static int remap_area_mfn_pte_fn(pte_t *ptep, pgtable_t token,
				 unsigned long addr, void *data)
{
	struct remap_data *rmd = data;
	pte_t pte = pte_mkspecial(pfn_pte(rmd->mfn++, rmd->prot));

2315
	rmd->mmu_update->ptr = virt_to_machine(ptep).maddr;
2316 2317 2318 2319 2320 2321 2322 2323 2324 2325 2326 2327 2328 2329 2330 2331 2332 2333 2334
	rmd->mmu_update->val = pte_val_ma(pte);
	rmd->mmu_update++;

	return 0;
}

int xen_remap_domain_mfn_range(struct vm_area_struct *vma,
			       unsigned long addr,
			       unsigned long mfn, int nr,
			       pgprot_t prot, unsigned domid)
{
	struct remap_data rmd;
	struct mmu_update mmu_update[REMAP_BATCH_SIZE];
	int batch;
	unsigned long range;
	int err = 0;

	prot = __pgprot(pgprot_val(prot) | _PAGE_IOMAP);

2335 2336
	BUG_ON(!((vma->vm_flags & (VM_PFNMAP | VM_RESERVED | VM_IO)) ==
				(VM_PFNMAP | VM_RESERVED | VM_IO)));
2337 2338 2339 2340 2341 2342 2343 2344 2345 2346 2347 2348 2349 2350 2351 2352 2353 2354 2355 2356 2357 2358 2359 2360 2361 2362 2363 2364 2365 2366

	rmd.mfn = mfn;
	rmd.prot = prot;

	while (nr) {
		batch = min(REMAP_BATCH_SIZE, nr);
		range = (unsigned long)batch << PAGE_SHIFT;

		rmd.mmu_update = mmu_update;
		err = apply_to_page_range(vma->vm_mm, addr, range,
					  remap_area_mfn_pte_fn, &rmd);
		if (err)
			goto out;

		err = -EFAULT;
		if (HYPERVISOR_mmu_update(mmu_update, batch, NULL, domid) < 0)
			goto out;

		nr -= batch;
		addr += range;
	}

	err = 0;
out:

	flush_tlb_all();

	return err;
}
EXPORT_SYMBOL_GPL(xen_remap_domain_mfn_range);