xref: /openbmc/linux/arch/x86/xen/mmu.c (revision e23feb16)
1 /*
2  * Xen mmu operations
3  *
4  * This file contains the various mmu fetch and update operations.
5  * The most important job they must perform is the mapping between the
6  * domain's pfn and the overall machine mfns.
7  *
8  * Xen allows guests to directly update the pagetable, in a controlled
9  * fashion.  In other words, the guest modifies the same pagetable
10  * that the CPU actually uses, which eliminates the overhead of having
11  * a separate shadow pagetable.
12  *
13  * In order to allow this, it falls on the guest domain to map its
14  * notion of a "physical" pfn - which is just a domain-local linear
15  * address - into a real "machine address" which the CPU's MMU can
16  * use.
17  *
18  * A pgd_t/pmd_t/pte_t will typically contain an mfn, and so can be
19  * inserted directly into the pagetable.  When creating a new
20  * pte/pmd/pgd, it converts the passed pfn into an mfn.  Conversely,
21  * when reading the content back with __(pgd|pmd|pte)_val, it converts
22  * the mfn back into a pfn.
23  *
24  * The other constraint is that all pages which make up a pagetable
25  * must be mapped read-only in the guest.  This prevents uncontrolled
26  * guest updates to the pagetable.  Xen strictly enforces this, and
27  * will disallow any pagetable update which will end up mapping a
28  * pagetable page RW, and will disallow using any writable page as a
29  * pagetable.
30  *
31  * Naively, when loading %cr3 with the base of a new pagetable, Xen
32  * would need to validate the whole pagetable before going on.
33  * Naturally, this is quite slow.  The solution is to "pin" a
34  * pagetable, which enforces all the constraints on the pagetable even
35  * when it is not actively in use.  This menas that Xen can be assured
36  * that it is still valid when you do load it into %cr3, and doesn't
37  * need to revalidate it.
38  *
39  * Jeremy Fitzhardinge <jeremy@xensource.com>, XenSource Inc, 2007
40  */
41 #include <linux/sched.h>
42 #include <linux/highmem.h>
43 #include <linux/debugfs.h>
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>
50 #include <linux/crash_dump.h>
51 
52 #include <trace/events/xen.h>
53 
54 #include <asm/pgtable.h>
55 #include <asm/tlbflush.h>
56 #include <asm/fixmap.h>
57 #include <asm/mmu_context.h>
58 #include <asm/setup.h>
59 #include <asm/paravirt.h>
60 #include <asm/e820.h>
61 #include <asm/linkage.h>
62 #include <asm/page.h>
63 #include <asm/init.h>
64 #include <asm/pat.h>
65 #include <asm/smp.h>
66 
67 #include <asm/xen/hypercall.h>
68 #include <asm/xen/hypervisor.h>
69 
70 #include <xen/xen.h>
71 #include <xen/page.h>
72 #include <xen/interface/xen.h>
73 #include <xen/interface/hvm/hvm_op.h>
74 #include <xen/interface/version.h>
75 #include <xen/interface/memory.h>
76 #include <xen/hvc-console.h>
77 
78 #include "multicalls.h"
79 #include "mmu.h"
80 #include "debugfs.h"
81 
82 /*
83  * Protects atomic reservation decrease/increase against concurrent increases.
84  * Also protects non-atomic updates of current_pages and balloon lists.
85  */
86 DEFINE_SPINLOCK(xen_reservation_lock);
87 
88 #ifdef CONFIG_X86_32
89 /*
90  * Identity map, in addition to plain kernel map.  This needs to be
91  * large enough to allocate page table pages to allocate the rest.
92  * Each page can map 2MB.
93  */
94 #define LEVEL1_IDENT_ENTRIES	(PTRS_PER_PTE * 4)
95 static RESERVE_BRK_ARRAY(pte_t, level1_ident_pgt, LEVEL1_IDENT_ENTRIES);
96 #endif
97 #ifdef CONFIG_X86_64
98 /* l3 pud for userspace vsyscall mapping */
99 static pud_t level3_user_vsyscall[PTRS_PER_PUD] __page_aligned_bss;
100 #endif /* CONFIG_X86_64 */
101 
102 /*
103  * Note about cr3 (pagetable base) values:
104  *
105  * xen_cr3 contains the current logical cr3 value; it contains the
106  * last set cr3.  This may not be the current effective cr3, because
107  * its update may be being lazily deferred.  However, a vcpu looking
108  * at its own cr3 can use this value knowing that it everything will
109  * be self-consistent.
110  *
111  * xen_current_cr3 contains the actual vcpu cr3; it is set once the
112  * hypercall to set the vcpu cr3 is complete (so it may be a little
113  * out of date, but it will never be set early).  If one vcpu is
114  * looking at another vcpu's cr3 value, it should use this variable.
115  */
116 DEFINE_PER_CPU(unsigned long, xen_cr3);	 /* cr3 stored as physaddr */
117 DEFINE_PER_CPU(unsigned long, xen_current_cr3);	 /* actual vcpu cr3 */
118 
119 
120 /*
121  * Just beyond the highest usermode address.  STACK_TOP_MAX has a
122  * redzone above it, so round it up to a PGD boundary.
123  */
124 #define USER_LIMIT	((STACK_TOP_MAX + PGDIR_SIZE - 1) & PGDIR_MASK)
125 
126 unsigned long arbitrary_virt_to_mfn(void *vaddr)
127 {
128 	xmaddr_t maddr = arbitrary_virt_to_machine(vaddr);
129 
130 	return PFN_DOWN(maddr.maddr);
131 }
132 
133 xmaddr_t arbitrary_virt_to_machine(void *vaddr)
134 {
135 	unsigned long address = (unsigned long)vaddr;
136 	unsigned int level;
137 	pte_t *pte;
138 	unsigned offset;
139 
140 	/*
141 	 * if the PFN is in the linear mapped vaddr range, we can just use
142 	 * the (quick) virt_to_machine() p2m lookup
143 	 */
144 	if (virt_addr_valid(vaddr))
145 		return virt_to_machine(vaddr);
146 
147 	/* otherwise we have to do a (slower) full page-table walk */
148 
149 	pte = lookup_address(address, &level);
150 	BUG_ON(pte == NULL);
151 	offset = address & ~PAGE_MASK;
152 	return XMADDR(((phys_addr_t)pte_mfn(*pte) << PAGE_SHIFT) + offset);
153 }
154 EXPORT_SYMBOL_GPL(arbitrary_virt_to_machine);
155 
156 void make_lowmem_page_readonly(void *vaddr)
157 {
158 	pte_t *pte, ptev;
159 	unsigned long address = (unsigned long)vaddr;
160 	unsigned int level;
161 
162 	pte = lookup_address(address, &level);
163 	if (pte == NULL)
164 		return;		/* vaddr missing */
165 
166 	ptev = pte_wrprotect(*pte);
167 
168 	if (HYPERVISOR_update_va_mapping(address, ptev, 0))
169 		BUG();
170 }
171 
172 void make_lowmem_page_readwrite(void *vaddr)
173 {
174 	pte_t *pte, ptev;
175 	unsigned long address = (unsigned long)vaddr;
176 	unsigned int level;
177 
178 	pte = lookup_address(address, &level);
179 	if (pte == NULL)
180 		return;		/* vaddr missing */
181 
182 	ptev = pte_mkwrite(*pte);
183 
184 	if (HYPERVISOR_update_va_mapping(address, ptev, 0))
185 		BUG();
186 }
187 
188 
189 static bool xen_page_pinned(void *ptr)
190 {
191 	struct page *page = virt_to_page(ptr);
192 
193 	return PagePinned(page);
194 }
195 
196 void xen_set_domain_pte(pte_t *ptep, pte_t pteval, unsigned domid)
197 {
198 	struct multicall_space mcs;
199 	struct mmu_update *u;
200 
201 	trace_xen_mmu_set_domain_pte(ptep, pteval, domid);
202 
203 	mcs = xen_mc_entry(sizeof(*u));
204 	u = mcs.args;
205 
206 	/* ptep might be kmapped when using 32-bit HIGHPTE */
207 	u->ptr = virt_to_machine(ptep).maddr;
208 	u->val = pte_val_ma(pteval);
209 
210 	MULTI_mmu_update(mcs.mc, mcs.args, 1, NULL, domid);
211 
212 	xen_mc_issue(PARAVIRT_LAZY_MMU);
213 }
214 EXPORT_SYMBOL_GPL(xen_set_domain_pte);
215 
216 static void xen_extend_mmu_update(const struct mmu_update *update)
217 {
218 	struct multicall_space mcs;
219 	struct mmu_update *u;
220 
221 	mcs = xen_mc_extend_args(__HYPERVISOR_mmu_update, sizeof(*u));
222 
223 	if (mcs.mc != NULL) {
224 		mcs.mc->args[1]++;
225 	} else {
226 		mcs = __xen_mc_entry(sizeof(*u));
227 		MULTI_mmu_update(mcs.mc, mcs.args, 1, NULL, DOMID_SELF);
228 	}
229 
230 	u = mcs.args;
231 	*u = *update;
232 }
233 
234 static void xen_extend_mmuext_op(const struct mmuext_op *op)
235 {
236 	struct multicall_space mcs;
237 	struct mmuext_op *u;
238 
239 	mcs = xen_mc_extend_args(__HYPERVISOR_mmuext_op, sizeof(*u));
240 
241 	if (mcs.mc != NULL) {
242 		mcs.mc->args[1]++;
243 	} else {
244 		mcs = __xen_mc_entry(sizeof(*u));
245 		MULTI_mmuext_op(mcs.mc, mcs.args, 1, NULL, DOMID_SELF);
246 	}
247 
248 	u = mcs.args;
249 	*u = *op;
250 }
251 
252 static void xen_set_pmd_hyper(pmd_t *ptr, pmd_t val)
253 {
254 	struct mmu_update u;
255 
256 	preempt_disable();
257 
258 	xen_mc_batch();
259 
260 	/* ptr may be ioremapped for 64-bit pagetable setup */
261 	u.ptr = arbitrary_virt_to_machine(ptr).maddr;
262 	u.val = pmd_val_ma(val);
263 	xen_extend_mmu_update(&u);
264 
265 	xen_mc_issue(PARAVIRT_LAZY_MMU);
266 
267 	preempt_enable();
268 }
269 
270 static void xen_set_pmd(pmd_t *ptr, pmd_t val)
271 {
272 	trace_xen_mmu_set_pmd(ptr, val);
273 
274 	/* If page is not pinned, we can just update the entry
275 	   directly */
276 	if (!xen_page_pinned(ptr)) {
277 		*ptr = val;
278 		return;
279 	}
280 
281 	xen_set_pmd_hyper(ptr, val);
282 }
283 
284 /*
285  * Associate a virtual page frame with a given physical page frame
286  * and protection flags for that frame.
287  */
288 void set_pte_mfn(unsigned long vaddr, unsigned long mfn, pgprot_t flags)
289 {
290 	set_pte_vaddr(vaddr, mfn_pte(mfn, flags));
291 }
292 
293 static bool xen_batched_set_pte(pte_t *ptep, pte_t pteval)
294 {
295 	struct mmu_update u;
296 
297 	if (paravirt_get_lazy_mode() != PARAVIRT_LAZY_MMU)
298 		return false;
299 
300 	xen_mc_batch();
301 
302 	u.ptr = virt_to_machine(ptep).maddr | MMU_NORMAL_PT_UPDATE;
303 	u.val = pte_val_ma(pteval);
304 	xen_extend_mmu_update(&u);
305 
306 	xen_mc_issue(PARAVIRT_LAZY_MMU);
307 
308 	return true;
309 }
310 
311 static inline void __xen_set_pte(pte_t *ptep, pte_t pteval)
312 {
313 	if (!xen_batched_set_pte(ptep, pteval)) {
314 		/*
315 		 * Could call native_set_pte() here and trap and
316 		 * emulate the PTE write but with 32-bit guests this
317 		 * needs two traps (one for each of the two 32-bit
318 		 * words in the PTE) so do one hypercall directly
319 		 * instead.
320 		 */
321 		struct mmu_update u;
322 
323 		u.ptr = virt_to_machine(ptep).maddr | MMU_NORMAL_PT_UPDATE;
324 		u.val = pte_val_ma(pteval);
325 		HYPERVISOR_mmu_update(&u, 1, NULL, DOMID_SELF);
326 	}
327 }
328 
329 static void xen_set_pte(pte_t *ptep, pte_t pteval)
330 {
331 	trace_xen_mmu_set_pte(ptep, pteval);
332 	__xen_set_pte(ptep, pteval);
333 }
334 
335 static void xen_set_pte_at(struct mm_struct *mm, unsigned long addr,
336 		    pte_t *ptep, pte_t pteval)
337 {
338 	trace_xen_mmu_set_pte_at(mm, addr, ptep, pteval);
339 	__xen_set_pte(ptep, pteval);
340 }
341 
342 pte_t xen_ptep_modify_prot_start(struct mm_struct *mm,
343 				 unsigned long addr, pte_t *ptep)
344 {
345 	/* Just return the pte as-is.  We preserve the bits on commit */
346 	trace_xen_mmu_ptep_modify_prot_start(mm, addr, ptep, *ptep);
347 	return *ptep;
348 }
349 
350 void xen_ptep_modify_prot_commit(struct mm_struct *mm, unsigned long addr,
351 				 pte_t *ptep, pte_t pte)
352 {
353 	struct mmu_update u;
354 
355 	trace_xen_mmu_ptep_modify_prot_commit(mm, addr, ptep, pte);
356 	xen_mc_batch();
357 
358 	u.ptr = virt_to_machine(ptep).maddr | MMU_PT_UPDATE_PRESERVE_AD;
359 	u.val = pte_val_ma(pte);
360 	xen_extend_mmu_update(&u);
361 
362 	xen_mc_issue(PARAVIRT_LAZY_MMU);
363 }
364 
365 /* Assume pteval_t is equivalent to all the other *val_t types. */
366 static pteval_t pte_mfn_to_pfn(pteval_t val)
367 {
368 	if (val & _PAGE_PRESENT) {
369 		unsigned long mfn = (val & PTE_PFN_MASK) >> PAGE_SHIFT;
370 		unsigned long pfn = mfn_to_pfn(mfn);
371 
372 		pteval_t flags = val & PTE_FLAGS_MASK;
373 		if (unlikely(pfn == ~0))
374 			val = flags & ~_PAGE_PRESENT;
375 		else
376 			val = ((pteval_t)pfn << PAGE_SHIFT) | flags;
377 	}
378 
379 	return val;
380 }
381 
382 static pteval_t pte_pfn_to_mfn(pteval_t val)
383 {
384 	if (val & _PAGE_PRESENT) {
385 		unsigned long pfn = (val & PTE_PFN_MASK) >> PAGE_SHIFT;
386 		pteval_t flags = val & PTE_FLAGS_MASK;
387 		unsigned long mfn;
388 
389 		if (!xen_feature(XENFEAT_auto_translated_physmap))
390 			mfn = get_phys_to_machine(pfn);
391 		else
392 			mfn = pfn;
393 		/*
394 		 * If there's no mfn for the pfn, then just create an
395 		 * empty non-present pte.  Unfortunately this loses
396 		 * information about the original pfn, so
397 		 * pte_mfn_to_pfn is asymmetric.
398 		 */
399 		if (unlikely(mfn == INVALID_P2M_ENTRY)) {
400 			mfn = 0;
401 			flags = 0;
402 		} else {
403 			/*
404 			 * Paramount to do this test _after_ the
405 			 * INVALID_P2M_ENTRY as INVALID_P2M_ENTRY &
406 			 * IDENTITY_FRAME_BIT resolves to true.
407 			 */
408 			mfn &= ~FOREIGN_FRAME_BIT;
409 			if (mfn & IDENTITY_FRAME_BIT) {
410 				mfn &= ~IDENTITY_FRAME_BIT;
411 				flags |= _PAGE_IOMAP;
412 			}
413 		}
414 		val = ((pteval_t)mfn << PAGE_SHIFT) | flags;
415 	}
416 
417 	return val;
418 }
419 
420 static pteval_t iomap_pte(pteval_t val)
421 {
422 	if (val & _PAGE_PRESENT) {
423 		unsigned long pfn = (val & PTE_PFN_MASK) >> PAGE_SHIFT;
424 		pteval_t flags = val & PTE_FLAGS_MASK;
425 
426 		/* We assume the pte frame number is a MFN, so
427 		   just use it as-is. */
428 		val = ((pteval_t)pfn << PAGE_SHIFT) | flags;
429 	}
430 
431 	return val;
432 }
433 
434 static pteval_t xen_pte_val(pte_t pte)
435 {
436 	pteval_t pteval = pte.pte;
437 #if 0
438 	/* If this is a WC pte, convert back from Xen WC to Linux WC */
439 	if ((pteval & (_PAGE_PAT | _PAGE_PCD | _PAGE_PWT)) == _PAGE_PAT) {
440 		WARN_ON(!pat_enabled);
441 		pteval = (pteval & ~_PAGE_PAT) | _PAGE_PWT;
442 	}
443 #endif
444 	if (xen_initial_domain() && (pteval & _PAGE_IOMAP))
445 		return pteval;
446 
447 	return pte_mfn_to_pfn(pteval);
448 }
449 PV_CALLEE_SAVE_REGS_THUNK(xen_pte_val);
450 
451 static pgdval_t xen_pgd_val(pgd_t pgd)
452 {
453 	return pte_mfn_to_pfn(pgd.pgd);
454 }
455 PV_CALLEE_SAVE_REGS_THUNK(xen_pgd_val);
456 
457 /*
458  * Xen's PAT setup is part of its ABI, though I assume entries 6 & 7
459  * are reserved for now, to correspond to the Intel-reserved PAT
460  * types.
461  *
462  * We expect Linux's PAT set as follows:
463  *
464  * Idx  PTE flags        Linux    Xen    Default
465  * 0                     WB       WB     WB
466  * 1            PWT      WC       WT     WT
467  * 2        PCD          UC-      UC-    UC-
468  * 3        PCD PWT      UC       UC     UC
469  * 4    PAT              WB       WC     WB
470  * 5    PAT     PWT      WC       WP     WT
471  * 6    PAT PCD          UC-      UC     UC-
472  * 7    PAT PCD PWT      UC       UC     UC
473  */
474 
475 void xen_set_pat(u64 pat)
476 {
477 	/* We expect Linux to use a PAT setting of
478 	 * UC UC- WC WB (ignoring the PAT flag) */
479 	WARN_ON(pat != 0x0007010600070106ull);
480 }
481 
482 static pte_t xen_make_pte(pteval_t pte)
483 {
484 	phys_addr_t addr = (pte & PTE_PFN_MASK);
485 #if 0
486 	/* If Linux is trying to set a WC pte, then map to the Xen WC.
487 	 * If _PAGE_PAT is set, then it probably means it is really
488 	 * _PAGE_PSE, so avoid fiddling with the PAT mapping and hope
489 	 * things work out OK...
490 	 *
491 	 * (We should never see kernel mappings with _PAGE_PSE set,
492 	 * but we could see hugetlbfs mappings, I think.).
493 	 */
494 	if (pat_enabled && !WARN_ON(pte & _PAGE_PAT)) {
495 		if ((pte & (_PAGE_PCD | _PAGE_PWT)) == _PAGE_PWT)
496 			pte = (pte & ~(_PAGE_PCD | _PAGE_PWT)) | _PAGE_PAT;
497 	}
498 #endif
499 	/*
500 	 * Unprivileged domains are allowed to do IOMAPpings for
501 	 * PCI passthrough, but not map ISA space.  The ISA
502 	 * mappings are just dummy local mappings to keep other
503 	 * parts of the kernel happy.
504 	 */
505 	if (unlikely(pte & _PAGE_IOMAP) &&
506 	    (xen_initial_domain() || addr >= ISA_END_ADDRESS)) {
507 		pte = iomap_pte(pte);
508 	} else {
509 		pte &= ~_PAGE_IOMAP;
510 		pte = pte_pfn_to_mfn(pte);
511 	}
512 
513 	return native_make_pte(pte);
514 }
515 PV_CALLEE_SAVE_REGS_THUNK(xen_make_pte);
516 
517 static pgd_t xen_make_pgd(pgdval_t pgd)
518 {
519 	pgd = pte_pfn_to_mfn(pgd);
520 	return native_make_pgd(pgd);
521 }
522 PV_CALLEE_SAVE_REGS_THUNK(xen_make_pgd);
523 
524 static pmdval_t xen_pmd_val(pmd_t pmd)
525 {
526 	return pte_mfn_to_pfn(pmd.pmd);
527 }
528 PV_CALLEE_SAVE_REGS_THUNK(xen_pmd_val);
529 
530 static void xen_set_pud_hyper(pud_t *ptr, pud_t val)
531 {
532 	struct mmu_update u;
533 
534 	preempt_disable();
535 
536 	xen_mc_batch();
537 
538 	/* ptr may be ioremapped for 64-bit pagetable setup */
539 	u.ptr = arbitrary_virt_to_machine(ptr).maddr;
540 	u.val = pud_val_ma(val);
541 	xen_extend_mmu_update(&u);
542 
543 	xen_mc_issue(PARAVIRT_LAZY_MMU);
544 
545 	preempt_enable();
546 }
547 
548 static void xen_set_pud(pud_t *ptr, pud_t val)
549 {
550 	trace_xen_mmu_set_pud(ptr, val);
551 
552 	/* If page is not pinned, we can just update the entry
553 	   directly */
554 	if (!xen_page_pinned(ptr)) {
555 		*ptr = val;
556 		return;
557 	}
558 
559 	xen_set_pud_hyper(ptr, val);
560 }
561 
562 #ifdef CONFIG_X86_PAE
563 static void xen_set_pte_atomic(pte_t *ptep, pte_t pte)
564 {
565 	trace_xen_mmu_set_pte_atomic(ptep, pte);
566 	set_64bit((u64 *)ptep, native_pte_val(pte));
567 }
568 
569 static void xen_pte_clear(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
570 {
571 	trace_xen_mmu_pte_clear(mm, addr, ptep);
572 	if (!xen_batched_set_pte(ptep, native_make_pte(0)))
573 		native_pte_clear(mm, addr, ptep);
574 }
575 
576 static void xen_pmd_clear(pmd_t *pmdp)
577 {
578 	trace_xen_mmu_pmd_clear(pmdp);
579 	set_pmd(pmdp, __pmd(0));
580 }
581 #endif	/* CONFIG_X86_PAE */
582 
583 static pmd_t xen_make_pmd(pmdval_t pmd)
584 {
585 	pmd = pte_pfn_to_mfn(pmd);
586 	return native_make_pmd(pmd);
587 }
588 PV_CALLEE_SAVE_REGS_THUNK(xen_make_pmd);
589 
590 #if PAGETABLE_LEVELS == 4
591 static pudval_t xen_pud_val(pud_t pud)
592 {
593 	return pte_mfn_to_pfn(pud.pud);
594 }
595 PV_CALLEE_SAVE_REGS_THUNK(xen_pud_val);
596 
597 static pud_t xen_make_pud(pudval_t pud)
598 {
599 	pud = pte_pfn_to_mfn(pud);
600 
601 	return native_make_pud(pud);
602 }
603 PV_CALLEE_SAVE_REGS_THUNK(xen_make_pud);
604 
605 static pgd_t *xen_get_user_pgd(pgd_t *pgd)
606 {
607 	pgd_t *pgd_page = (pgd_t *)(((unsigned long)pgd) & PAGE_MASK);
608 	unsigned offset = pgd - pgd_page;
609 	pgd_t *user_ptr = NULL;
610 
611 	if (offset < pgd_index(USER_LIMIT)) {
612 		struct page *page = virt_to_page(pgd_page);
613 		user_ptr = (pgd_t *)page->private;
614 		if (user_ptr)
615 			user_ptr += offset;
616 	}
617 
618 	return user_ptr;
619 }
620 
621 static void __xen_set_pgd_hyper(pgd_t *ptr, pgd_t val)
622 {
623 	struct mmu_update u;
624 
625 	u.ptr = virt_to_machine(ptr).maddr;
626 	u.val = pgd_val_ma(val);
627 	xen_extend_mmu_update(&u);
628 }
629 
630 /*
631  * Raw hypercall-based set_pgd, intended for in early boot before
632  * there's a page structure.  This implies:
633  *  1. The only existing pagetable is the kernel's
634  *  2. It is always pinned
635  *  3. It has no user pagetable attached to it
636  */
637 static void __init xen_set_pgd_hyper(pgd_t *ptr, pgd_t val)
638 {
639 	preempt_disable();
640 
641 	xen_mc_batch();
642 
643 	__xen_set_pgd_hyper(ptr, val);
644 
645 	xen_mc_issue(PARAVIRT_LAZY_MMU);
646 
647 	preempt_enable();
648 }
649 
650 static void xen_set_pgd(pgd_t *ptr, pgd_t val)
651 {
652 	pgd_t *user_ptr = xen_get_user_pgd(ptr);
653 
654 	trace_xen_mmu_set_pgd(ptr, user_ptr, val);
655 
656 	/* If page is not pinned, we can just update the entry
657 	   directly */
658 	if (!xen_page_pinned(ptr)) {
659 		*ptr = val;
660 		if (user_ptr) {
661 			WARN_ON(xen_page_pinned(user_ptr));
662 			*user_ptr = val;
663 		}
664 		return;
665 	}
666 
667 	/* If it's pinned, then we can at least batch the kernel and
668 	   user updates together. */
669 	xen_mc_batch();
670 
671 	__xen_set_pgd_hyper(ptr, val);
672 	if (user_ptr)
673 		__xen_set_pgd_hyper(user_ptr, val);
674 
675 	xen_mc_issue(PARAVIRT_LAZY_MMU);
676 }
677 #endif	/* PAGETABLE_LEVELS == 4 */
678 
679 /*
680  * (Yet another) pagetable walker.  This one is intended for pinning a
681  * pagetable.  This means that it walks a pagetable and calls the
682  * callback function on each page it finds making up the page table,
683  * at every level.  It walks the entire pagetable, but it only bothers
684  * pinning pte pages which are below limit.  In the normal case this
685  * will be STACK_TOP_MAX, but at boot we need to pin up to
686  * FIXADDR_TOP.
687  *
688  * For 32-bit the important bit is that we don't pin beyond there,
689  * because then we start getting into Xen's ptes.
690  *
691  * For 64-bit, we must skip the Xen hole in the middle of the address
692  * space, just after the big x86-64 virtual hole.
693  */
694 static int __xen_pgd_walk(struct mm_struct *mm, pgd_t *pgd,
695 			  int (*func)(struct mm_struct *mm, struct page *,
696 				      enum pt_level),
697 			  unsigned long limit)
698 {
699 	int flush = 0;
700 	unsigned hole_low, hole_high;
701 	unsigned pgdidx_limit, pudidx_limit, pmdidx_limit;
702 	unsigned pgdidx, pudidx, pmdidx;
703 
704 	/* The limit is the last byte to be touched */
705 	limit--;
706 	BUG_ON(limit >= FIXADDR_TOP);
707 
708 	if (xen_feature(XENFEAT_auto_translated_physmap))
709 		return 0;
710 
711 	/*
712 	 * 64-bit has a great big hole in the middle of the address
713 	 * space, which contains the Xen mappings.  On 32-bit these
714 	 * will end up making a zero-sized hole and so is a no-op.
715 	 */
716 	hole_low = pgd_index(USER_LIMIT);
717 	hole_high = pgd_index(PAGE_OFFSET);
718 
719 	pgdidx_limit = pgd_index(limit);
720 #if PTRS_PER_PUD > 1
721 	pudidx_limit = pud_index(limit);
722 #else
723 	pudidx_limit = 0;
724 #endif
725 #if PTRS_PER_PMD > 1
726 	pmdidx_limit = pmd_index(limit);
727 #else
728 	pmdidx_limit = 0;
729 #endif
730 
731 	for (pgdidx = 0; pgdidx <= pgdidx_limit; pgdidx++) {
732 		pud_t *pud;
733 
734 		if (pgdidx >= hole_low && pgdidx < hole_high)
735 			continue;
736 
737 		if (!pgd_val(pgd[pgdidx]))
738 			continue;
739 
740 		pud = pud_offset(&pgd[pgdidx], 0);
741 
742 		if (PTRS_PER_PUD > 1) /* not folded */
743 			flush |= (*func)(mm, virt_to_page(pud), PT_PUD);
744 
745 		for (pudidx = 0; pudidx < PTRS_PER_PUD; pudidx++) {
746 			pmd_t *pmd;
747 
748 			if (pgdidx == pgdidx_limit &&
749 			    pudidx > pudidx_limit)
750 				goto out;
751 
752 			if (pud_none(pud[pudidx]))
753 				continue;
754 
755 			pmd = pmd_offset(&pud[pudidx], 0);
756 
757 			if (PTRS_PER_PMD > 1) /* not folded */
758 				flush |= (*func)(mm, virt_to_page(pmd), PT_PMD);
759 
760 			for (pmdidx = 0; pmdidx < PTRS_PER_PMD; pmdidx++) {
761 				struct page *pte;
762 
763 				if (pgdidx == pgdidx_limit &&
764 				    pudidx == pudidx_limit &&
765 				    pmdidx > pmdidx_limit)
766 					goto out;
767 
768 				if (pmd_none(pmd[pmdidx]))
769 					continue;
770 
771 				pte = pmd_page(pmd[pmdidx]);
772 				flush |= (*func)(mm, pte, PT_PTE);
773 			}
774 		}
775 	}
776 
777 out:
778 	/* Do the top level last, so that the callbacks can use it as
779 	   a cue to do final things like tlb flushes. */
780 	flush |= (*func)(mm, virt_to_page(pgd), PT_PGD);
781 
782 	return flush;
783 }
784 
785 static int xen_pgd_walk(struct mm_struct *mm,
786 			int (*func)(struct mm_struct *mm, struct page *,
787 				    enum pt_level),
788 			unsigned long limit)
789 {
790 	return __xen_pgd_walk(mm, mm->pgd, func, limit);
791 }
792 
793 /* If we're using split pte locks, then take the page's lock and
794    return a pointer to it.  Otherwise return NULL. */
795 static spinlock_t *xen_pte_lock(struct page *page, struct mm_struct *mm)
796 {
797 	spinlock_t *ptl = NULL;
798 
799 #if USE_SPLIT_PTLOCKS
800 	ptl = __pte_lockptr(page);
801 	spin_lock_nest_lock(ptl, &mm->page_table_lock);
802 #endif
803 
804 	return ptl;
805 }
806 
807 static void xen_pte_unlock(void *v)
808 {
809 	spinlock_t *ptl = v;
810 	spin_unlock(ptl);
811 }
812 
813 static void xen_do_pin(unsigned level, unsigned long pfn)
814 {
815 	struct mmuext_op op;
816 
817 	op.cmd = level;
818 	op.arg1.mfn = pfn_to_mfn(pfn);
819 
820 	xen_extend_mmuext_op(&op);
821 }
822 
823 static int xen_pin_page(struct mm_struct *mm, struct page *page,
824 			enum pt_level level)
825 {
826 	unsigned pgfl = TestSetPagePinned(page);
827 	int flush;
828 
829 	if (pgfl)
830 		flush = 0;		/* already pinned */
831 	else if (PageHighMem(page))
832 		/* kmaps need flushing if we found an unpinned
833 		   highpage */
834 		flush = 1;
835 	else {
836 		void *pt = lowmem_page_address(page);
837 		unsigned long pfn = page_to_pfn(page);
838 		struct multicall_space mcs = __xen_mc_entry(0);
839 		spinlock_t *ptl;
840 
841 		flush = 0;
842 
843 		/*
844 		 * We need to hold the pagetable lock between the time
845 		 * we make the pagetable RO and when we actually pin
846 		 * it.  If we don't, then other users may come in and
847 		 * attempt to update the pagetable by writing it,
848 		 * which will fail because the memory is RO but not
849 		 * pinned, so Xen won't do the trap'n'emulate.
850 		 *
851 		 * If we're using split pte locks, we can't hold the
852 		 * entire pagetable's worth of locks during the
853 		 * traverse, because we may wrap the preempt count (8
854 		 * bits).  The solution is to mark RO and pin each PTE
855 		 * page while holding the lock.  This means the number
856 		 * of locks we end up holding is never more than a
857 		 * batch size (~32 entries, at present).
858 		 *
859 		 * If we're not using split pte locks, we needn't pin
860 		 * the PTE pages independently, because we're
861 		 * protected by the overall pagetable lock.
862 		 */
863 		ptl = NULL;
864 		if (level == PT_PTE)
865 			ptl = xen_pte_lock(page, mm);
866 
867 		MULTI_update_va_mapping(mcs.mc, (unsigned long)pt,
868 					pfn_pte(pfn, PAGE_KERNEL_RO),
869 					level == PT_PGD ? UVMF_TLB_FLUSH : 0);
870 
871 		if (ptl) {
872 			xen_do_pin(MMUEXT_PIN_L1_TABLE, pfn);
873 
874 			/* Queue a deferred unlock for when this batch
875 			   is completed. */
876 			xen_mc_callback(xen_pte_unlock, ptl);
877 		}
878 	}
879 
880 	return flush;
881 }
882 
883 /* This is called just after a mm has been created, but it has not
884    been used yet.  We need to make sure that its pagetable is all
885    read-only, and can be pinned. */
886 static void __xen_pgd_pin(struct mm_struct *mm, pgd_t *pgd)
887 {
888 	trace_xen_mmu_pgd_pin(mm, pgd);
889 
890 	xen_mc_batch();
891 
892 	if (__xen_pgd_walk(mm, pgd, xen_pin_page, USER_LIMIT)) {
893 		/* re-enable interrupts for flushing */
894 		xen_mc_issue(0);
895 
896 		kmap_flush_unused();
897 
898 		xen_mc_batch();
899 	}
900 
901 #ifdef CONFIG_X86_64
902 	{
903 		pgd_t *user_pgd = xen_get_user_pgd(pgd);
904 
905 		xen_do_pin(MMUEXT_PIN_L4_TABLE, PFN_DOWN(__pa(pgd)));
906 
907 		if (user_pgd) {
908 			xen_pin_page(mm, virt_to_page(user_pgd), PT_PGD);
909 			xen_do_pin(MMUEXT_PIN_L4_TABLE,
910 				   PFN_DOWN(__pa(user_pgd)));
911 		}
912 	}
913 #else /* CONFIG_X86_32 */
914 #ifdef CONFIG_X86_PAE
915 	/* Need to make sure unshared kernel PMD is pinnable */
916 	xen_pin_page(mm, pgd_page(pgd[pgd_index(TASK_SIZE)]),
917 		     PT_PMD);
918 #endif
919 	xen_do_pin(MMUEXT_PIN_L3_TABLE, PFN_DOWN(__pa(pgd)));
920 #endif /* CONFIG_X86_64 */
921 	xen_mc_issue(0);
922 }
923 
924 static void xen_pgd_pin(struct mm_struct *mm)
925 {
926 	__xen_pgd_pin(mm, mm->pgd);
927 }
928 
929 /*
930  * On save, we need to pin all pagetables to make sure they get their
931  * mfns turned into pfns.  Search the list for any unpinned pgds and pin
932  * them (unpinned pgds are not currently in use, probably because the
933  * process is under construction or destruction).
934  *
935  * Expected to be called in stop_machine() ("equivalent to taking
936  * every spinlock in the system"), so the locking doesn't really
937  * matter all that much.
938  */
939 void xen_mm_pin_all(void)
940 {
941 	struct page *page;
942 
943 	spin_lock(&pgd_lock);
944 
945 	list_for_each_entry(page, &pgd_list, lru) {
946 		if (!PagePinned(page)) {
947 			__xen_pgd_pin(&init_mm, (pgd_t *)page_address(page));
948 			SetPageSavePinned(page);
949 		}
950 	}
951 
952 	spin_unlock(&pgd_lock);
953 }
954 
955 /*
956  * The init_mm pagetable is really pinned as soon as its created, but
957  * that's before we have page structures to store the bits.  So do all
958  * the book-keeping now.
959  */
960 static int __init xen_mark_pinned(struct mm_struct *mm, struct page *page,
961 				  enum pt_level level)
962 {
963 	SetPagePinned(page);
964 	return 0;
965 }
966 
967 static void __init xen_mark_init_mm_pinned(void)
968 {
969 	xen_pgd_walk(&init_mm, xen_mark_pinned, FIXADDR_TOP);
970 }
971 
972 static int xen_unpin_page(struct mm_struct *mm, struct page *page,
973 			  enum pt_level level)
974 {
975 	unsigned pgfl = TestClearPagePinned(page);
976 
977 	if (pgfl && !PageHighMem(page)) {
978 		void *pt = lowmem_page_address(page);
979 		unsigned long pfn = page_to_pfn(page);
980 		spinlock_t *ptl = NULL;
981 		struct multicall_space mcs;
982 
983 		/*
984 		 * Do the converse to pin_page.  If we're using split
985 		 * pte locks, we must be holding the lock for while
986 		 * the pte page is unpinned but still RO to prevent
987 		 * concurrent updates from seeing it in this
988 		 * partially-pinned state.
989 		 */
990 		if (level == PT_PTE) {
991 			ptl = xen_pte_lock(page, mm);
992 
993 			if (ptl)
994 				xen_do_pin(MMUEXT_UNPIN_TABLE, pfn);
995 		}
996 
997 		mcs = __xen_mc_entry(0);
998 
999 		MULTI_update_va_mapping(mcs.mc, (unsigned long)pt,
1000 					pfn_pte(pfn, PAGE_KERNEL),
1001 					level == PT_PGD ? UVMF_TLB_FLUSH : 0);
1002 
1003 		if (ptl) {
1004 			/* unlock when batch completed */
1005 			xen_mc_callback(xen_pte_unlock, ptl);
1006 		}
1007 	}
1008 
1009 	return 0;		/* never need to flush on unpin */
1010 }
1011 
1012 /* Release a pagetables pages back as normal RW */
1013 static void __xen_pgd_unpin(struct mm_struct *mm, pgd_t *pgd)
1014 {
1015 	trace_xen_mmu_pgd_unpin(mm, pgd);
1016 
1017 	xen_mc_batch();
1018 
1019 	xen_do_pin(MMUEXT_UNPIN_TABLE, PFN_DOWN(__pa(pgd)));
1020 
1021 #ifdef CONFIG_X86_64
1022 	{
1023 		pgd_t *user_pgd = xen_get_user_pgd(pgd);
1024 
1025 		if (user_pgd) {
1026 			xen_do_pin(MMUEXT_UNPIN_TABLE,
1027 				   PFN_DOWN(__pa(user_pgd)));
1028 			xen_unpin_page(mm, virt_to_page(user_pgd), PT_PGD);
1029 		}
1030 	}
1031 #endif
1032 
1033 #ifdef CONFIG_X86_PAE
1034 	/* Need to make sure unshared kernel PMD is unpinned */
1035 	xen_unpin_page(mm, pgd_page(pgd[pgd_index(TASK_SIZE)]),
1036 		       PT_PMD);
1037 #endif
1038 
1039 	__xen_pgd_walk(mm, pgd, xen_unpin_page, USER_LIMIT);
1040 
1041 	xen_mc_issue(0);
1042 }
1043 
1044 static void xen_pgd_unpin(struct mm_struct *mm)
1045 {
1046 	__xen_pgd_unpin(mm, mm->pgd);
1047 }
1048 
1049 /*
1050  * On resume, undo any pinning done at save, so that the rest of the
1051  * kernel doesn't see any unexpected pinned pagetables.
1052  */
1053 void xen_mm_unpin_all(void)
1054 {
1055 	struct page *page;
1056 
1057 	spin_lock(&pgd_lock);
1058 
1059 	list_for_each_entry(page, &pgd_list, lru) {
1060 		if (PageSavePinned(page)) {
1061 			BUG_ON(!PagePinned(page));
1062 			__xen_pgd_unpin(&init_mm, (pgd_t *)page_address(page));
1063 			ClearPageSavePinned(page);
1064 		}
1065 	}
1066 
1067 	spin_unlock(&pgd_lock);
1068 }
1069 
1070 static void xen_activate_mm(struct mm_struct *prev, struct mm_struct *next)
1071 {
1072 	spin_lock(&next->page_table_lock);
1073 	xen_pgd_pin(next);
1074 	spin_unlock(&next->page_table_lock);
1075 }
1076 
1077 static void xen_dup_mmap(struct mm_struct *oldmm, struct mm_struct *mm)
1078 {
1079 	spin_lock(&mm->page_table_lock);
1080 	xen_pgd_pin(mm);
1081 	spin_unlock(&mm->page_table_lock);
1082 }
1083 
1084 
1085 #ifdef CONFIG_SMP
1086 /* Another cpu may still have their %cr3 pointing at the pagetable, so
1087    we need to repoint it somewhere else before we can unpin it. */
1088 static void drop_other_mm_ref(void *info)
1089 {
1090 	struct mm_struct *mm = info;
1091 	struct mm_struct *active_mm;
1092 
1093 	active_mm = this_cpu_read(cpu_tlbstate.active_mm);
1094 
1095 	if (active_mm == mm && this_cpu_read(cpu_tlbstate.state) != TLBSTATE_OK)
1096 		leave_mm(smp_processor_id());
1097 
1098 	/* If this cpu still has a stale cr3 reference, then make sure
1099 	   it has been flushed. */
1100 	if (this_cpu_read(xen_current_cr3) == __pa(mm->pgd))
1101 		load_cr3(swapper_pg_dir);
1102 }
1103 
1104 static void xen_drop_mm_ref(struct mm_struct *mm)
1105 {
1106 	cpumask_var_t mask;
1107 	unsigned cpu;
1108 
1109 	if (current->active_mm == mm) {
1110 		if (current->mm == mm)
1111 			load_cr3(swapper_pg_dir);
1112 		else
1113 			leave_mm(smp_processor_id());
1114 	}
1115 
1116 	/* Get the "official" set of cpus referring to our pagetable. */
1117 	if (!alloc_cpumask_var(&mask, GFP_ATOMIC)) {
1118 		for_each_online_cpu(cpu) {
1119 			if (!cpumask_test_cpu(cpu, mm_cpumask(mm))
1120 			    && per_cpu(xen_current_cr3, cpu) != __pa(mm->pgd))
1121 				continue;
1122 			smp_call_function_single(cpu, drop_other_mm_ref, mm, 1);
1123 		}
1124 		return;
1125 	}
1126 	cpumask_copy(mask, mm_cpumask(mm));
1127 
1128 	/* It's possible that a vcpu may have a stale reference to our
1129 	   cr3, because its in lazy mode, and it hasn't yet flushed
1130 	   its set of pending hypercalls yet.  In this case, we can
1131 	   look at its actual current cr3 value, and force it to flush
1132 	   if needed. */
1133 	for_each_online_cpu(cpu) {
1134 		if (per_cpu(xen_current_cr3, cpu) == __pa(mm->pgd))
1135 			cpumask_set_cpu(cpu, mask);
1136 	}
1137 
1138 	if (!cpumask_empty(mask))
1139 		smp_call_function_many(mask, drop_other_mm_ref, mm, 1);
1140 	free_cpumask_var(mask);
1141 }
1142 #else
1143 static void xen_drop_mm_ref(struct mm_struct *mm)
1144 {
1145 	if (current->active_mm == mm)
1146 		load_cr3(swapper_pg_dir);
1147 }
1148 #endif
1149 
1150 /*
1151  * While a process runs, Xen pins its pagetables, which means that the
1152  * hypervisor forces it to be read-only, and it controls all updates
1153  * to it.  This means that all pagetable updates have to go via the
1154  * hypervisor, which is moderately expensive.
1155  *
1156  * Since we're pulling the pagetable down, we switch to use init_mm,
1157  * unpin old process pagetable and mark it all read-write, which
1158  * allows further operations on it to be simple memory accesses.
1159  *
1160  * The only subtle point is that another CPU may be still using the
1161  * pagetable because of lazy tlb flushing.  This means we need need to
1162  * switch all CPUs off this pagetable before we can unpin it.
1163  */
1164 static void xen_exit_mmap(struct mm_struct *mm)
1165 {
1166 	get_cpu();		/* make sure we don't move around */
1167 	xen_drop_mm_ref(mm);
1168 	put_cpu();
1169 
1170 	spin_lock(&mm->page_table_lock);
1171 
1172 	/* pgd may not be pinned in the error exit path of execve */
1173 	if (xen_page_pinned(mm->pgd))
1174 		xen_pgd_unpin(mm);
1175 
1176 	spin_unlock(&mm->page_table_lock);
1177 }
1178 
1179 static void xen_post_allocator_init(void);
1180 
1181 #ifdef CONFIG_X86_64
1182 static void __init xen_cleanhighmap(unsigned long vaddr,
1183 				    unsigned long vaddr_end)
1184 {
1185 	unsigned long kernel_end = roundup((unsigned long)_brk_end, PMD_SIZE) - 1;
1186 	pmd_t *pmd = level2_kernel_pgt + pmd_index(vaddr);
1187 
1188 	/* NOTE: The loop is more greedy than the cleanup_highmap variant.
1189 	 * We include the PMD passed in on _both_ boundaries. */
1190 	for (; vaddr <= vaddr_end && (pmd < (level2_kernel_pgt + PAGE_SIZE));
1191 			pmd++, vaddr += PMD_SIZE) {
1192 		if (pmd_none(*pmd))
1193 			continue;
1194 		if (vaddr < (unsigned long) _text || vaddr > kernel_end)
1195 			set_pmd(pmd, __pmd(0));
1196 	}
1197 	/* In case we did something silly, we should crash in this function
1198 	 * instead of somewhere later and be confusing. */
1199 	xen_mc_flush();
1200 }
1201 #endif
1202 static void __init xen_pagetable_init(void)
1203 {
1204 #ifdef CONFIG_X86_64
1205 	unsigned long size;
1206 	unsigned long addr;
1207 #endif
1208 	paging_init();
1209 	xen_setup_shared_info();
1210 #ifdef CONFIG_X86_64
1211 	if (!xen_feature(XENFEAT_auto_translated_physmap)) {
1212 		unsigned long new_mfn_list;
1213 
1214 		size = PAGE_ALIGN(xen_start_info->nr_pages * sizeof(unsigned long));
1215 
1216 		/* On 32-bit, we get zero so this never gets executed. */
1217 		new_mfn_list = xen_revector_p2m_tree();
1218 		if (new_mfn_list && new_mfn_list != xen_start_info->mfn_list) {
1219 			/* using __ka address and sticking INVALID_P2M_ENTRY! */
1220 			memset((void *)xen_start_info->mfn_list, 0xff, size);
1221 
1222 			/* We should be in __ka space. */
1223 			BUG_ON(xen_start_info->mfn_list < __START_KERNEL_map);
1224 			addr = xen_start_info->mfn_list;
1225 			/* We roundup to the PMD, which means that if anybody at this stage is
1226 			 * using the __ka address of xen_start_info or xen_start_info->shared_info
1227 			 * they are in going to crash. Fortunatly we have already revectored
1228 			 * in xen_setup_kernel_pagetable and in xen_setup_shared_info. */
1229 			size = roundup(size, PMD_SIZE);
1230 			xen_cleanhighmap(addr, addr + size);
1231 
1232 			size = PAGE_ALIGN(xen_start_info->nr_pages * sizeof(unsigned long));
1233 			memblock_free(__pa(xen_start_info->mfn_list), size);
1234 			/* And revector! Bye bye old array */
1235 			xen_start_info->mfn_list = new_mfn_list;
1236 		} else
1237 			goto skip;
1238 	}
1239 	/* At this stage, cleanup_highmap has already cleaned __ka space
1240 	 * from _brk_limit way up to the max_pfn_mapped (which is the end of
1241 	 * the ramdisk). We continue on, erasing PMD entries that point to page
1242 	 * tables - do note that they are accessible at this stage via __va.
1243 	 * For good measure we also round up to the PMD - which means that if
1244 	 * anybody is using __ka address to the initial boot-stack - and try
1245 	 * to use it - they are going to crash. The xen_start_info has been
1246 	 * taken care of already in xen_setup_kernel_pagetable. */
1247 	addr = xen_start_info->pt_base;
1248 	size = roundup(xen_start_info->nr_pt_frames * PAGE_SIZE, PMD_SIZE);
1249 
1250 	xen_cleanhighmap(addr, addr + size);
1251 	xen_start_info->pt_base = (unsigned long)__va(__pa(xen_start_info->pt_base));
1252 #ifdef DEBUG
1253 	/* This is superflous and is not neccessary, but you know what
1254 	 * lets do it. The MODULES_VADDR -> MODULES_END should be clear of
1255 	 * anything at this stage. */
1256 	xen_cleanhighmap(MODULES_VADDR, roundup(MODULES_VADDR, PUD_SIZE) - 1);
1257 #endif
1258 skip:
1259 #endif
1260 	xen_post_allocator_init();
1261 }
1262 static void xen_write_cr2(unsigned long cr2)
1263 {
1264 	this_cpu_read(xen_vcpu)->arch.cr2 = cr2;
1265 }
1266 
1267 static unsigned long xen_read_cr2(void)
1268 {
1269 	return this_cpu_read(xen_vcpu)->arch.cr2;
1270 }
1271 
1272 unsigned long xen_read_cr2_direct(void)
1273 {
1274 	return this_cpu_read(xen_vcpu_info.arch.cr2);
1275 }
1276 
1277 void xen_flush_tlb_all(void)
1278 {
1279 	struct mmuext_op *op;
1280 	struct multicall_space mcs;
1281 
1282 	trace_xen_mmu_flush_tlb_all(0);
1283 
1284 	preempt_disable();
1285 
1286 	mcs = xen_mc_entry(sizeof(*op));
1287 
1288 	op = mcs.args;
1289 	op->cmd = MMUEXT_TLB_FLUSH_ALL;
1290 	MULTI_mmuext_op(mcs.mc, op, 1, NULL, DOMID_SELF);
1291 
1292 	xen_mc_issue(PARAVIRT_LAZY_MMU);
1293 
1294 	preempt_enable();
1295 }
1296 static void xen_flush_tlb(void)
1297 {
1298 	struct mmuext_op *op;
1299 	struct multicall_space mcs;
1300 
1301 	trace_xen_mmu_flush_tlb(0);
1302 
1303 	preempt_disable();
1304 
1305 	mcs = xen_mc_entry(sizeof(*op));
1306 
1307 	op = mcs.args;
1308 	op->cmd = MMUEXT_TLB_FLUSH_LOCAL;
1309 	MULTI_mmuext_op(mcs.mc, op, 1, NULL, DOMID_SELF);
1310 
1311 	xen_mc_issue(PARAVIRT_LAZY_MMU);
1312 
1313 	preempt_enable();
1314 }
1315 
1316 static void xen_flush_tlb_single(unsigned long addr)
1317 {
1318 	struct mmuext_op *op;
1319 	struct multicall_space mcs;
1320 
1321 	trace_xen_mmu_flush_tlb_single(addr);
1322 
1323 	preempt_disable();
1324 
1325 	mcs = xen_mc_entry(sizeof(*op));
1326 	op = mcs.args;
1327 	op->cmd = MMUEXT_INVLPG_LOCAL;
1328 	op->arg1.linear_addr = addr & PAGE_MASK;
1329 	MULTI_mmuext_op(mcs.mc, op, 1, NULL, DOMID_SELF);
1330 
1331 	xen_mc_issue(PARAVIRT_LAZY_MMU);
1332 
1333 	preempt_enable();
1334 }
1335 
1336 static void xen_flush_tlb_others(const struct cpumask *cpus,
1337 				 struct mm_struct *mm, unsigned long start,
1338 				 unsigned long end)
1339 {
1340 	struct {
1341 		struct mmuext_op op;
1342 #ifdef CONFIG_SMP
1343 		DECLARE_BITMAP(mask, num_processors);
1344 #else
1345 		DECLARE_BITMAP(mask, NR_CPUS);
1346 #endif
1347 	} *args;
1348 	struct multicall_space mcs;
1349 
1350 	trace_xen_mmu_flush_tlb_others(cpus, mm, start, end);
1351 
1352 	if (cpumask_empty(cpus))
1353 		return;		/* nothing to do */
1354 
1355 	mcs = xen_mc_entry(sizeof(*args));
1356 	args = mcs.args;
1357 	args->op.arg2.vcpumask = to_cpumask(args->mask);
1358 
1359 	/* Remove us, and any offline CPUS. */
1360 	cpumask_and(to_cpumask(args->mask), cpus, cpu_online_mask);
1361 	cpumask_clear_cpu(smp_processor_id(), to_cpumask(args->mask));
1362 
1363 	args->op.cmd = MMUEXT_TLB_FLUSH_MULTI;
1364 	if (end != TLB_FLUSH_ALL && (end - start) <= PAGE_SIZE) {
1365 		args->op.cmd = MMUEXT_INVLPG_MULTI;
1366 		args->op.arg1.linear_addr = start;
1367 	}
1368 
1369 	MULTI_mmuext_op(mcs.mc, &args->op, 1, NULL, DOMID_SELF);
1370 
1371 	xen_mc_issue(PARAVIRT_LAZY_MMU);
1372 }
1373 
1374 static unsigned long xen_read_cr3(void)
1375 {
1376 	return this_cpu_read(xen_cr3);
1377 }
1378 
1379 static void set_current_cr3(void *v)
1380 {
1381 	this_cpu_write(xen_current_cr3, (unsigned long)v);
1382 }
1383 
1384 static void __xen_write_cr3(bool kernel, unsigned long cr3)
1385 {
1386 	struct mmuext_op op;
1387 	unsigned long mfn;
1388 
1389 	trace_xen_mmu_write_cr3(kernel, cr3);
1390 
1391 	if (cr3)
1392 		mfn = pfn_to_mfn(PFN_DOWN(cr3));
1393 	else
1394 		mfn = 0;
1395 
1396 	WARN_ON(mfn == 0 && kernel);
1397 
1398 	op.cmd = kernel ? MMUEXT_NEW_BASEPTR : MMUEXT_NEW_USER_BASEPTR;
1399 	op.arg1.mfn = mfn;
1400 
1401 	xen_extend_mmuext_op(&op);
1402 
1403 	if (kernel) {
1404 		this_cpu_write(xen_cr3, cr3);
1405 
1406 		/* Update xen_current_cr3 once the batch has actually
1407 		   been submitted. */
1408 		xen_mc_callback(set_current_cr3, (void *)cr3);
1409 	}
1410 }
1411 static void xen_write_cr3(unsigned long cr3)
1412 {
1413 	BUG_ON(preemptible());
1414 
1415 	xen_mc_batch();  /* disables interrupts */
1416 
1417 	/* Update while interrupts are disabled, so its atomic with
1418 	   respect to ipis */
1419 	this_cpu_write(xen_cr3, cr3);
1420 
1421 	__xen_write_cr3(true, cr3);
1422 
1423 #ifdef CONFIG_X86_64
1424 	{
1425 		pgd_t *user_pgd = xen_get_user_pgd(__va(cr3));
1426 		if (user_pgd)
1427 			__xen_write_cr3(false, __pa(user_pgd));
1428 		else
1429 			__xen_write_cr3(false, 0);
1430 	}
1431 #endif
1432 
1433 	xen_mc_issue(PARAVIRT_LAZY_CPU);  /* interrupts restored */
1434 }
1435 
1436 #ifdef CONFIG_X86_64
1437 /*
1438  * At the start of the day - when Xen launches a guest, it has already
1439  * built pagetables for the guest. We diligently look over them
1440  * in xen_setup_kernel_pagetable and graft as appropiate them in the
1441  * init_level4_pgt and its friends. Then when we are happy we load
1442  * the new init_level4_pgt - and continue on.
1443  *
1444  * The generic code starts (start_kernel) and 'init_mem_mapping' sets
1445  * up the rest of the pagetables. When it has completed it loads the cr3.
1446  * N.B. that baremetal would start at 'start_kernel' (and the early
1447  * #PF handler would create bootstrap pagetables) - so we are running
1448  * with the same assumptions as what to do when write_cr3 is executed
1449  * at this point.
1450  *
1451  * Since there are no user-page tables at all, we have two variants
1452  * of xen_write_cr3 - the early bootup (this one), and the late one
1453  * (xen_write_cr3). The reason we have to do that is that in 64-bit
1454  * the Linux kernel and user-space are both in ring 3 while the
1455  * hypervisor is in ring 0.
1456  */
1457 static void __init xen_write_cr3_init(unsigned long cr3)
1458 {
1459 	BUG_ON(preemptible());
1460 
1461 	xen_mc_batch();  /* disables interrupts */
1462 
1463 	/* Update while interrupts are disabled, so its atomic with
1464 	   respect to ipis */
1465 	this_cpu_write(xen_cr3, cr3);
1466 
1467 	__xen_write_cr3(true, cr3);
1468 
1469 	xen_mc_issue(PARAVIRT_LAZY_CPU);  /* interrupts restored */
1470 }
1471 #endif
1472 
1473 static int xen_pgd_alloc(struct mm_struct *mm)
1474 {
1475 	pgd_t *pgd = mm->pgd;
1476 	int ret = 0;
1477 
1478 	BUG_ON(PagePinned(virt_to_page(pgd)));
1479 
1480 #ifdef CONFIG_X86_64
1481 	{
1482 		struct page *page = virt_to_page(pgd);
1483 		pgd_t *user_pgd;
1484 
1485 		BUG_ON(page->private != 0);
1486 
1487 		ret = -ENOMEM;
1488 
1489 		user_pgd = (pgd_t *)__get_free_page(GFP_KERNEL | __GFP_ZERO);
1490 		page->private = (unsigned long)user_pgd;
1491 
1492 		if (user_pgd != NULL) {
1493 			user_pgd[pgd_index(VSYSCALL_START)] =
1494 				__pgd(__pa(level3_user_vsyscall) | _PAGE_TABLE);
1495 			ret = 0;
1496 		}
1497 
1498 		BUG_ON(PagePinned(virt_to_page(xen_get_user_pgd(pgd))));
1499 	}
1500 #endif
1501 
1502 	return ret;
1503 }
1504 
1505 static void xen_pgd_free(struct mm_struct *mm, pgd_t *pgd)
1506 {
1507 #ifdef CONFIG_X86_64
1508 	pgd_t *user_pgd = xen_get_user_pgd(pgd);
1509 
1510 	if (user_pgd)
1511 		free_page((unsigned long)user_pgd);
1512 #endif
1513 }
1514 
1515 #ifdef CONFIG_X86_32
1516 static pte_t __init mask_rw_pte(pte_t *ptep, pte_t pte)
1517 {
1518 	/* If there's an existing pte, then don't allow _PAGE_RW to be set */
1519 	if (pte_val_ma(*ptep) & _PAGE_PRESENT)
1520 		pte = __pte_ma(((pte_val_ma(*ptep) & _PAGE_RW) | ~_PAGE_RW) &
1521 			       pte_val_ma(pte));
1522 
1523 	return pte;
1524 }
1525 #else /* CONFIG_X86_64 */
1526 static pte_t __init mask_rw_pte(pte_t *ptep, pte_t pte)
1527 {
1528 	return pte;
1529 }
1530 #endif /* CONFIG_X86_64 */
1531 
1532 /*
1533  * Init-time set_pte while constructing initial pagetables, which
1534  * doesn't allow RO page table pages to be remapped RW.
1535  *
1536  * If there is no MFN for this PFN then this page is initially
1537  * ballooned out so clear the PTE (as in decrease_reservation() in
1538  * drivers/xen/balloon.c).
1539  *
1540  * Many of these PTE updates are done on unpinned and writable pages
1541  * and doing a hypercall for these is unnecessary and expensive.  At
1542  * this point it is not possible to tell if a page is pinned or not,
1543  * so always write the PTE directly and rely on Xen trapping and
1544  * emulating any updates as necessary.
1545  */
1546 static void __init xen_set_pte_init(pte_t *ptep, pte_t pte)
1547 {
1548 	if (pte_mfn(pte) != INVALID_P2M_ENTRY)
1549 		pte = mask_rw_pte(ptep, pte);
1550 	else
1551 		pte = __pte_ma(0);
1552 
1553 	native_set_pte(ptep, pte);
1554 }
1555 
1556 static void pin_pagetable_pfn(unsigned cmd, unsigned long pfn)
1557 {
1558 	struct mmuext_op op;
1559 	op.cmd = cmd;
1560 	op.arg1.mfn = pfn_to_mfn(pfn);
1561 	if (HYPERVISOR_mmuext_op(&op, 1, NULL, DOMID_SELF))
1562 		BUG();
1563 }
1564 
1565 /* Early in boot, while setting up the initial pagetable, assume
1566    everything is pinned. */
1567 static void __init xen_alloc_pte_init(struct mm_struct *mm, unsigned long pfn)
1568 {
1569 #ifdef CONFIG_FLATMEM
1570 	BUG_ON(mem_map);	/* should only be used early */
1571 #endif
1572 	make_lowmem_page_readonly(__va(PFN_PHYS(pfn)));
1573 	pin_pagetable_pfn(MMUEXT_PIN_L1_TABLE, pfn);
1574 }
1575 
1576 /* Used for pmd and pud */
1577 static void __init xen_alloc_pmd_init(struct mm_struct *mm, unsigned long pfn)
1578 {
1579 #ifdef CONFIG_FLATMEM
1580 	BUG_ON(mem_map);	/* should only be used early */
1581 #endif
1582 	make_lowmem_page_readonly(__va(PFN_PHYS(pfn)));
1583 }
1584 
1585 /* Early release_pte assumes that all pts are pinned, since there's
1586    only init_mm and anything attached to that is pinned. */
1587 static void __init xen_release_pte_init(unsigned long pfn)
1588 {
1589 	pin_pagetable_pfn(MMUEXT_UNPIN_TABLE, pfn);
1590 	make_lowmem_page_readwrite(__va(PFN_PHYS(pfn)));
1591 }
1592 
1593 static void __init xen_release_pmd_init(unsigned long pfn)
1594 {
1595 	make_lowmem_page_readwrite(__va(PFN_PHYS(pfn)));
1596 }
1597 
1598 static inline void __pin_pagetable_pfn(unsigned cmd, unsigned long pfn)
1599 {
1600 	struct multicall_space mcs;
1601 	struct mmuext_op *op;
1602 
1603 	mcs = __xen_mc_entry(sizeof(*op));
1604 	op = mcs.args;
1605 	op->cmd = cmd;
1606 	op->arg1.mfn = pfn_to_mfn(pfn);
1607 
1608 	MULTI_mmuext_op(mcs.mc, mcs.args, 1, NULL, DOMID_SELF);
1609 }
1610 
1611 static inline void __set_pfn_prot(unsigned long pfn, pgprot_t prot)
1612 {
1613 	struct multicall_space mcs;
1614 	unsigned long addr = (unsigned long)__va(pfn << PAGE_SHIFT);
1615 
1616 	mcs = __xen_mc_entry(0);
1617 	MULTI_update_va_mapping(mcs.mc, (unsigned long)addr,
1618 				pfn_pte(pfn, prot), 0);
1619 }
1620 
1621 /* This needs to make sure the new pte page is pinned iff its being
1622    attached to a pinned pagetable. */
1623 static inline void xen_alloc_ptpage(struct mm_struct *mm, unsigned long pfn,
1624 				    unsigned level)
1625 {
1626 	bool pinned = PagePinned(virt_to_page(mm->pgd));
1627 
1628 	trace_xen_mmu_alloc_ptpage(mm, pfn, level, pinned);
1629 
1630 	if (pinned) {
1631 		struct page *page = pfn_to_page(pfn);
1632 
1633 		SetPagePinned(page);
1634 
1635 		if (!PageHighMem(page)) {
1636 			xen_mc_batch();
1637 
1638 			__set_pfn_prot(pfn, PAGE_KERNEL_RO);
1639 
1640 			if (level == PT_PTE && USE_SPLIT_PTLOCKS)
1641 				__pin_pagetable_pfn(MMUEXT_PIN_L1_TABLE, pfn);
1642 
1643 			xen_mc_issue(PARAVIRT_LAZY_MMU);
1644 		} else {
1645 			/* make sure there are no stray mappings of
1646 			   this page */
1647 			kmap_flush_unused();
1648 		}
1649 	}
1650 }
1651 
1652 static void xen_alloc_pte(struct mm_struct *mm, unsigned long pfn)
1653 {
1654 	xen_alloc_ptpage(mm, pfn, PT_PTE);
1655 }
1656 
1657 static void xen_alloc_pmd(struct mm_struct *mm, unsigned long pfn)
1658 {
1659 	xen_alloc_ptpage(mm, pfn, PT_PMD);
1660 }
1661 
1662 /* This should never happen until we're OK to use struct page */
1663 static inline void xen_release_ptpage(unsigned long pfn, unsigned level)
1664 {
1665 	struct page *page = pfn_to_page(pfn);
1666 	bool pinned = PagePinned(page);
1667 
1668 	trace_xen_mmu_release_ptpage(pfn, level, pinned);
1669 
1670 	if (pinned) {
1671 		if (!PageHighMem(page)) {
1672 			xen_mc_batch();
1673 
1674 			if (level == PT_PTE && USE_SPLIT_PTLOCKS)
1675 				__pin_pagetable_pfn(MMUEXT_UNPIN_TABLE, pfn);
1676 
1677 			__set_pfn_prot(pfn, PAGE_KERNEL);
1678 
1679 			xen_mc_issue(PARAVIRT_LAZY_MMU);
1680 		}
1681 		ClearPagePinned(page);
1682 	}
1683 }
1684 
1685 static void xen_release_pte(unsigned long pfn)
1686 {
1687 	xen_release_ptpage(pfn, PT_PTE);
1688 }
1689 
1690 static void xen_release_pmd(unsigned long pfn)
1691 {
1692 	xen_release_ptpage(pfn, PT_PMD);
1693 }
1694 
1695 #if PAGETABLE_LEVELS == 4
1696 static void xen_alloc_pud(struct mm_struct *mm, unsigned long pfn)
1697 {
1698 	xen_alloc_ptpage(mm, pfn, PT_PUD);
1699 }
1700 
1701 static void xen_release_pud(unsigned long pfn)
1702 {
1703 	xen_release_ptpage(pfn, PT_PUD);
1704 }
1705 #endif
1706 
1707 void __init xen_reserve_top(void)
1708 {
1709 #ifdef CONFIG_X86_32
1710 	unsigned long top = HYPERVISOR_VIRT_START;
1711 	struct xen_platform_parameters pp;
1712 
1713 	if (HYPERVISOR_xen_version(XENVER_platform_parameters, &pp) == 0)
1714 		top = pp.virt_start;
1715 
1716 	reserve_top_address(-top);
1717 #endif	/* CONFIG_X86_32 */
1718 }
1719 
1720 /*
1721  * Like __va(), but returns address in the kernel mapping (which is
1722  * all we have until the physical memory mapping has been set up.
1723  */
1724 static void *__ka(phys_addr_t paddr)
1725 {
1726 #ifdef CONFIG_X86_64
1727 	return (void *)(paddr + __START_KERNEL_map);
1728 #else
1729 	return __va(paddr);
1730 #endif
1731 }
1732 
1733 /* Convert a machine address to physical address */
1734 static unsigned long m2p(phys_addr_t maddr)
1735 {
1736 	phys_addr_t paddr;
1737 
1738 	maddr &= PTE_PFN_MASK;
1739 	paddr = mfn_to_pfn(maddr >> PAGE_SHIFT) << PAGE_SHIFT;
1740 
1741 	return paddr;
1742 }
1743 
1744 /* Convert a machine address to kernel virtual */
1745 static void *m2v(phys_addr_t maddr)
1746 {
1747 	return __ka(m2p(maddr));
1748 }
1749 
1750 /* Set the page permissions on an identity-mapped pages */
1751 static void set_page_prot_flags(void *addr, pgprot_t prot, unsigned long flags)
1752 {
1753 	unsigned long pfn = __pa(addr) >> PAGE_SHIFT;
1754 	pte_t pte = pfn_pte(pfn, prot);
1755 
1756 	if (HYPERVISOR_update_va_mapping((unsigned long)addr, pte, flags))
1757 		BUG();
1758 }
1759 static void set_page_prot(void *addr, pgprot_t prot)
1760 {
1761 	return set_page_prot_flags(addr, prot, UVMF_NONE);
1762 }
1763 #ifdef CONFIG_X86_32
1764 static void __init xen_map_identity_early(pmd_t *pmd, unsigned long max_pfn)
1765 {
1766 	unsigned pmdidx, pteidx;
1767 	unsigned ident_pte;
1768 	unsigned long pfn;
1769 
1770 	level1_ident_pgt = extend_brk(sizeof(pte_t) * LEVEL1_IDENT_ENTRIES,
1771 				      PAGE_SIZE);
1772 
1773 	ident_pte = 0;
1774 	pfn = 0;
1775 	for (pmdidx = 0; pmdidx < PTRS_PER_PMD && pfn < max_pfn; pmdidx++) {
1776 		pte_t *pte_page;
1777 
1778 		/* Reuse or allocate a page of ptes */
1779 		if (pmd_present(pmd[pmdidx]))
1780 			pte_page = m2v(pmd[pmdidx].pmd);
1781 		else {
1782 			/* Check for free pte pages */
1783 			if (ident_pte == LEVEL1_IDENT_ENTRIES)
1784 				break;
1785 
1786 			pte_page = &level1_ident_pgt[ident_pte];
1787 			ident_pte += PTRS_PER_PTE;
1788 
1789 			pmd[pmdidx] = __pmd(__pa(pte_page) | _PAGE_TABLE);
1790 		}
1791 
1792 		/* Install mappings */
1793 		for (pteidx = 0; pteidx < PTRS_PER_PTE; pteidx++, pfn++) {
1794 			pte_t pte;
1795 
1796 #ifdef CONFIG_X86_32
1797 			if (pfn > max_pfn_mapped)
1798 				max_pfn_mapped = pfn;
1799 #endif
1800 
1801 			if (!pte_none(pte_page[pteidx]))
1802 				continue;
1803 
1804 			pte = pfn_pte(pfn, PAGE_KERNEL_EXEC);
1805 			pte_page[pteidx] = pte;
1806 		}
1807 	}
1808 
1809 	for (pteidx = 0; pteidx < ident_pte; pteidx += PTRS_PER_PTE)
1810 		set_page_prot(&level1_ident_pgt[pteidx], PAGE_KERNEL_RO);
1811 
1812 	set_page_prot(pmd, PAGE_KERNEL_RO);
1813 }
1814 #endif
1815 void __init xen_setup_machphys_mapping(void)
1816 {
1817 	struct xen_machphys_mapping mapping;
1818 
1819 	if (HYPERVISOR_memory_op(XENMEM_machphys_mapping, &mapping) == 0) {
1820 		machine_to_phys_mapping = (unsigned long *)mapping.v_start;
1821 		machine_to_phys_nr = mapping.max_mfn + 1;
1822 	} else {
1823 		machine_to_phys_nr = MACH2PHYS_NR_ENTRIES;
1824 	}
1825 #ifdef CONFIG_X86_32
1826 	WARN_ON((machine_to_phys_mapping + (machine_to_phys_nr - 1))
1827 		< machine_to_phys_mapping);
1828 #endif
1829 }
1830 
1831 #ifdef CONFIG_X86_64
1832 static void convert_pfn_mfn(void *v)
1833 {
1834 	pte_t *pte = v;
1835 	int i;
1836 
1837 	/* All levels are converted the same way, so just treat them
1838 	   as ptes. */
1839 	for (i = 0; i < PTRS_PER_PTE; i++)
1840 		pte[i] = xen_make_pte(pte[i].pte);
1841 }
1842 static void __init check_pt_base(unsigned long *pt_base, unsigned long *pt_end,
1843 				 unsigned long addr)
1844 {
1845 	if (*pt_base == PFN_DOWN(__pa(addr))) {
1846 		set_page_prot_flags((void *)addr, PAGE_KERNEL, UVMF_INVLPG);
1847 		clear_page((void *)addr);
1848 		(*pt_base)++;
1849 	}
1850 	if (*pt_end == PFN_DOWN(__pa(addr))) {
1851 		set_page_prot_flags((void *)addr, PAGE_KERNEL, UVMF_INVLPG);
1852 		clear_page((void *)addr);
1853 		(*pt_end)--;
1854 	}
1855 }
1856 /*
1857  * Set up the initial kernel pagetable.
1858  *
1859  * We can construct this by grafting the Xen provided pagetable into
1860  * head_64.S's preconstructed pagetables.  We copy the Xen L2's into
1861  * level2_ident_pgt, level2_kernel_pgt and level2_fixmap_pgt.  This
1862  * means that only the kernel has a physical mapping to start with -
1863  * but that's enough to get __va working.  We need to fill in the rest
1864  * of the physical mapping once some sort of allocator has been set
1865  * up.
1866  */
1867 void __init xen_setup_kernel_pagetable(pgd_t *pgd, unsigned long max_pfn)
1868 {
1869 	pud_t *l3;
1870 	pmd_t *l2;
1871 	unsigned long addr[3];
1872 	unsigned long pt_base, pt_end;
1873 	unsigned i;
1874 
1875 	/* max_pfn_mapped is the last pfn mapped in the initial memory
1876 	 * mappings. Considering that on Xen after the kernel mappings we
1877 	 * have the mappings of some pages that don't exist in pfn space, we
1878 	 * set max_pfn_mapped to the last real pfn mapped. */
1879 	max_pfn_mapped = PFN_DOWN(__pa(xen_start_info->mfn_list));
1880 
1881 	pt_base = PFN_DOWN(__pa(xen_start_info->pt_base));
1882 	pt_end = pt_base + xen_start_info->nr_pt_frames;
1883 
1884 	/* Zap identity mapping */
1885 	init_level4_pgt[0] = __pgd(0);
1886 
1887 	/* Pre-constructed entries are in pfn, so convert to mfn */
1888 	/* L4[272] -> level3_ident_pgt
1889 	 * L4[511] -> level3_kernel_pgt */
1890 	convert_pfn_mfn(init_level4_pgt);
1891 
1892 	/* L3_i[0] -> level2_ident_pgt */
1893 	convert_pfn_mfn(level3_ident_pgt);
1894 	/* L3_k[510] -> level2_kernel_pgt
1895 	 * L3_i[511] -> level2_fixmap_pgt */
1896 	convert_pfn_mfn(level3_kernel_pgt);
1897 
1898 	/* We get [511][511] and have Xen's version of level2_kernel_pgt */
1899 	l3 = m2v(pgd[pgd_index(__START_KERNEL_map)].pgd);
1900 	l2 = m2v(l3[pud_index(__START_KERNEL_map)].pud);
1901 
1902 	addr[0] = (unsigned long)pgd;
1903 	addr[1] = (unsigned long)l3;
1904 	addr[2] = (unsigned long)l2;
1905 	/* Graft it onto L4[272][0]. Note that we creating an aliasing problem:
1906 	 * Both L4[272][0] and L4[511][511] have entries that point to the same
1907 	 * L2 (PMD) tables. Meaning that if you modify it in __va space
1908 	 * it will be also modified in the __ka space! (But if you just
1909 	 * modify the PMD table to point to other PTE's or none, then you
1910 	 * are OK - which is what cleanup_highmap does) */
1911 	copy_page(level2_ident_pgt, l2);
1912 	/* Graft it onto L4[511][511] */
1913 	copy_page(level2_kernel_pgt, l2);
1914 
1915 	/* Get [511][510] and graft that in level2_fixmap_pgt */
1916 	l3 = m2v(pgd[pgd_index(__START_KERNEL_map + PMD_SIZE)].pgd);
1917 	l2 = m2v(l3[pud_index(__START_KERNEL_map + PMD_SIZE)].pud);
1918 	copy_page(level2_fixmap_pgt, l2);
1919 	/* Note that we don't do anything with level1_fixmap_pgt which
1920 	 * we don't need. */
1921 
1922 	/* Make pagetable pieces RO */
1923 	set_page_prot(init_level4_pgt, PAGE_KERNEL_RO);
1924 	set_page_prot(level3_ident_pgt, PAGE_KERNEL_RO);
1925 	set_page_prot(level3_kernel_pgt, PAGE_KERNEL_RO);
1926 	set_page_prot(level3_user_vsyscall, PAGE_KERNEL_RO);
1927 	set_page_prot(level2_ident_pgt, PAGE_KERNEL_RO);
1928 	set_page_prot(level2_kernel_pgt, PAGE_KERNEL_RO);
1929 	set_page_prot(level2_fixmap_pgt, PAGE_KERNEL_RO);
1930 
1931 	/* Pin down new L4 */
1932 	pin_pagetable_pfn(MMUEXT_PIN_L4_TABLE,
1933 			  PFN_DOWN(__pa_symbol(init_level4_pgt)));
1934 
1935 	/* Unpin Xen-provided one */
1936 	pin_pagetable_pfn(MMUEXT_UNPIN_TABLE, PFN_DOWN(__pa(pgd)));
1937 
1938 	/*
1939 	 * At this stage there can be no user pgd, and no page
1940 	 * structure to attach it to, so make sure we just set kernel
1941 	 * pgd.
1942 	 */
1943 	xen_mc_batch();
1944 	__xen_write_cr3(true, __pa(init_level4_pgt));
1945 	xen_mc_issue(PARAVIRT_LAZY_CPU);
1946 
1947 	/* We can't that easily rip out L3 and L2, as the Xen pagetables are
1948 	 * set out this way: [L4], [L1], [L2], [L3], [L1], [L1] ...  for
1949 	 * the initial domain. For guests using the toolstack, they are in:
1950 	 * [L4], [L3], [L2], [L1], [L1], order .. So for dom0 we can only
1951 	 * rip out the [L4] (pgd), but for guests we shave off three pages.
1952 	 */
1953 	for (i = 0; i < ARRAY_SIZE(addr); i++)
1954 		check_pt_base(&pt_base, &pt_end, addr[i]);
1955 
1956 	/* Our (by three pages) smaller Xen pagetable that we are using */
1957 	memblock_reserve(PFN_PHYS(pt_base), (pt_end - pt_base) * PAGE_SIZE);
1958 	/* Revector the xen_start_info */
1959 	xen_start_info = (struct start_info *)__va(__pa(xen_start_info));
1960 }
1961 #else	/* !CONFIG_X86_64 */
1962 static RESERVE_BRK_ARRAY(pmd_t, initial_kernel_pmd, PTRS_PER_PMD);
1963 static RESERVE_BRK_ARRAY(pmd_t, swapper_kernel_pmd, PTRS_PER_PMD);
1964 
1965 static void __init xen_write_cr3_init(unsigned long cr3)
1966 {
1967 	unsigned long pfn = PFN_DOWN(__pa(swapper_pg_dir));
1968 
1969 	BUG_ON(read_cr3() != __pa(initial_page_table));
1970 	BUG_ON(cr3 != __pa(swapper_pg_dir));
1971 
1972 	/*
1973 	 * We are switching to swapper_pg_dir for the first time (from
1974 	 * initial_page_table) and therefore need to mark that page
1975 	 * read-only and then pin it.
1976 	 *
1977 	 * Xen disallows sharing of kernel PMDs for PAE
1978 	 * guests. Therefore we must copy the kernel PMD from
1979 	 * initial_page_table into a new kernel PMD to be used in
1980 	 * swapper_pg_dir.
1981 	 */
1982 	swapper_kernel_pmd =
1983 		extend_brk(sizeof(pmd_t) * PTRS_PER_PMD, PAGE_SIZE);
1984 	copy_page(swapper_kernel_pmd, initial_kernel_pmd);
1985 	swapper_pg_dir[KERNEL_PGD_BOUNDARY] =
1986 		__pgd(__pa(swapper_kernel_pmd) | _PAGE_PRESENT);
1987 	set_page_prot(swapper_kernel_pmd, PAGE_KERNEL_RO);
1988 
1989 	set_page_prot(swapper_pg_dir, PAGE_KERNEL_RO);
1990 	xen_write_cr3(cr3);
1991 	pin_pagetable_pfn(MMUEXT_PIN_L3_TABLE, pfn);
1992 
1993 	pin_pagetable_pfn(MMUEXT_UNPIN_TABLE,
1994 			  PFN_DOWN(__pa(initial_page_table)));
1995 	set_page_prot(initial_page_table, PAGE_KERNEL);
1996 	set_page_prot(initial_kernel_pmd, PAGE_KERNEL);
1997 
1998 	pv_mmu_ops.write_cr3 = &xen_write_cr3;
1999 }
2000 
2001 void __init xen_setup_kernel_pagetable(pgd_t *pgd, unsigned long max_pfn)
2002 {
2003 	pmd_t *kernel_pmd;
2004 
2005 	initial_kernel_pmd =
2006 		extend_brk(sizeof(pmd_t) * PTRS_PER_PMD, PAGE_SIZE);
2007 
2008 	max_pfn_mapped = PFN_DOWN(__pa(xen_start_info->pt_base) +
2009 				  xen_start_info->nr_pt_frames * PAGE_SIZE +
2010 				  512*1024);
2011 
2012 	kernel_pmd = m2v(pgd[KERNEL_PGD_BOUNDARY].pgd);
2013 	copy_page(initial_kernel_pmd, kernel_pmd);
2014 
2015 	xen_map_identity_early(initial_kernel_pmd, max_pfn);
2016 
2017 	copy_page(initial_page_table, pgd);
2018 	initial_page_table[KERNEL_PGD_BOUNDARY] =
2019 		__pgd(__pa(initial_kernel_pmd) | _PAGE_PRESENT);
2020 
2021 	set_page_prot(initial_kernel_pmd, PAGE_KERNEL_RO);
2022 	set_page_prot(initial_page_table, PAGE_KERNEL_RO);
2023 	set_page_prot(empty_zero_page, PAGE_KERNEL_RO);
2024 
2025 	pin_pagetable_pfn(MMUEXT_UNPIN_TABLE, PFN_DOWN(__pa(pgd)));
2026 
2027 	pin_pagetable_pfn(MMUEXT_PIN_L3_TABLE,
2028 			  PFN_DOWN(__pa(initial_page_table)));
2029 	xen_write_cr3(__pa(initial_page_table));
2030 
2031 	memblock_reserve(__pa(xen_start_info->pt_base),
2032 			 xen_start_info->nr_pt_frames * PAGE_SIZE);
2033 }
2034 #endif	/* CONFIG_X86_64 */
2035 
2036 static unsigned char dummy_mapping[PAGE_SIZE] __page_aligned_bss;
2037 
2038 static void xen_set_fixmap(unsigned idx, phys_addr_t phys, pgprot_t prot)
2039 {
2040 	pte_t pte;
2041 
2042 	phys >>= PAGE_SHIFT;
2043 
2044 	switch (idx) {
2045 	case FIX_BTMAP_END ... FIX_BTMAP_BEGIN:
2046 	case FIX_RO_IDT:
2047 #ifdef CONFIG_X86_32
2048 	case FIX_WP_TEST:
2049 	case FIX_VDSO:
2050 # ifdef CONFIG_HIGHMEM
2051 	case FIX_KMAP_BEGIN ... FIX_KMAP_END:
2052 # endif
2053 #else
2054 	case VSYSCALL_LAST_PAGE ... VSYSCALL_FIRST_PAGE:
2055 	case VVAR_PAGE:
2056 #endif
2057 	case FIX_TEXT_POKE0:
2058 	case FIX_TEXT_POKE1:
2059 		/* All local page mappings */
2060 		pte = pfn_pte(phys, prot);
2061 		break;
2062 
2063 #ifdef CONFIG_X86_LOCAL_APIC
2064 	case FIX_APIC_BASE:	/* maps dummy local APIC */
2065 		pte = pfn_pte(PFN_DOWN(__pa(dummy_mapping)), PAGE_KERNEL);
2066 		break;
2067 #endif
2068 
2069 #ifdef CONFIG_X86_IO_APIC
2070 	case FIX_IO_APIC_BASE_0 ... FIX_IO_APIC_BASE_END:
2071 		/*
2072 		 * We just don't map the IO APIC - all access is via
2073 		 * hypercalls.  Keep the address in the pte for reference.
2074 		 */
2075 		pte = pfn_pte(PFN_DOWN(__pa(dummy_mapping)), PAGE_KERNEL);
2076 		break;
2077 #endif
2078 
2079 	case FIX_PARAVIRT_BOOTMAP:
2080 		/* This is an MFN, but it isn't an IO mapping from the
2081 		   IO domain */
2082 		pte = mfn_pte(phys, prot);
2083 		break;
2084 
2085 	default:
2086 		/* By default, set_fixmap is used for hardware mappings */
2087 		pte = mfn_pte(phys, __pgprot(pgprot_val(prot) | _PAGE_IOMAP));
2088 		break;
2089 	}
2090 
2091 	__native_set_fixmap(idx, pte);
2092 
2093 #ifdef CONFIG_X86_64
2094 	/* Replicate changes to map the vsyscall page into the user
2095 	   pagetable vsyscall mapping. */
2096 	if ((idx >= VSYSCALL_LAST_PAGE && idx <= VSYSCALL_FIRST_PAGE) ||
2097 	    idx == VVAR_PAGE) {
2098 		unsigned long vaddr = __fix_to_virt(idx);
2099 		set_pte_vaddr_pud(level3_user_vsyscall, vaddr, pte);
2100 	}
2101 #endif
2102 }
2103 
2104 static void __init xen_post_allocator_init(void)
2105 {
2106 	pv_mmu_ops.set_pte = xen_set_pte;
2107 	pv_mmu_ops.set_pmd = xen_set_pmd;
2108 	pv_mmu_ops.set_pud = xen_set_pud;
2109 #if PAGETABLE_LEVELS == 4
2110 	pv_mmu_ops.set_pgd = xen_set_pgd;
2111 #endif
2112 
2113 	/* This will work as long as patching hasn't happened yet
2114 	   (which it hasn't) */
2115 	pv_mmu_ops.alloc_pte = xen_alloc_pte;
2116 	pv_mmu_ops.alloc_pmd = xen_alloc_pmd;
2117 	pv_mmu_ops.release_pte = xen_release_pte;
2118 	pv_mmu_ops.release_pmd = xen_release_pmd;
2119 #if PAGETABLE_LEVELS == 4
2120 	pv_mmu_ops.alloc_pud = xen_alloc_pud;
2121 	pv_mmu_ops.release_pud = xen_release_pud;
2122 #endif
2123 
2124 #ifdef CONFIG_X86_64
2125 	pv_mmu_ops.write_cr3 = &xen_write_cr3;
2126 	SetPagePinned(virt_to_page(level3_user_vsyscall));
2127 #endif
2128 	xen_mark_init_mm_pinned();
2129 }
2130 
2131 static void xen_leave_lazy_mmu(void)
2132 {
2133 	preempt_disable();
2134 	xen_mc_flush();
2135 	paravirt_leave_lazy_mmu();
2136 	preempt_enable();
2137 }
2138 
2139 static const struct pv_mmu_ops xen_mmu_ops __initconst = {
2140 	.read_cr2 = xen_read_cr2,
2141 	.write_cr2 = xen_write_cr2,
2142 
2143 	.read_cr3 = xen_read_cr3,
2144 	.write_cr3 = xen_write_cr3_init,
2145 
2146 	.flush_tlb_user = xen_flush_tlb,
2147 	.flush_tlb_kernel = xen_flush_tlb,
2148 	.flush_tlb_single = xen_flush_tlb_single,
2149 	.flush_tlb_others = xen_flush_tlb_others,
2150 
2151 	.pte_update = paravirt_nop,
2152 	.pte_update_defer = paravirt_nop,
2153 
2154 	.pgd_alloc = xen_pgd_alloc,
2155 	.pgd_free = xen_pgd_free,
2156 
2157 	.alloc_pte = xen_alloc_pte_init,
2158 	.release_pte = xen_release_pte_init,
2159 	.alloc_pmd = xen_alloc_pmd_init,
2160 	.release_pmd = xen_release_pmd_init,
2161 
2162 	.set_pte = xen_set_pte_init,
2163 	.set_pte_at = xen_set_pte_at,
2164 	.set_pmd = xen_set_pmd_hyper,
2165 
2166 	.ptep_modify_prot_start = __ptep_modify_prot_start,
2167 	.ptep_modify_prot_commit = __ptep_modify_prot_commit,
2168 
2169 	.pte_val = PV_CALLEE_SAVE(xen_pte_val),
2170 	.pgd_val = PV_CALLEE_SAVE(xen_pgd_val),
2171 
2172 	.make_pte = PV_CALLEE_SAVE(xen_make_pte),
2173 	.make_pgd = PV_CALLEE_SAVE(xen_make_pgd),
2174 
2175 #ifdef CONFIG_X86_PAE
2176 	.set_pte_atomic = xen_set_pte_atomic,
2177 	.pte_clear = xen_pte_clear,
2178 	.pmd_clear = xen_pmd_clear,
2179 #endif	/* CONFIG_X86_PAE */
2180 	.set_pud = xen_set_pud_hyper,
2181 
2182 	.make_pmd = PV_CALLEE_SAVE(xen_make_pmd),
2183 	.pmd_val = PV_CALLEE_SAVE(xen_pmd_val),
2184 
2185 #if PAGETABLE_LEVELS == 4
2186 	.pud_val = PV_CALLEE_SAVE(xen_pud_val),
2187 	.make_pud = PV_CALLEE_SAVE(xen_make_pud),
2188 	.set_pgd = xen_set_pgd_hyper,
2189 
2190 	.alloc_pud = xen_alloc_pmd_init,
2191 	.release_pud = xen_release_pmd_init,
2192 #endif	/* PAGETABLE_LEVELS == 4 */
2193 
2194 	.activate_mm = xen_activate_mm,
2195 	.dup_mmap = xen_dup_mmap,
2196 	.exit_mmap = xen_exit_mmap,
2197 
2198 	.lazy_mode = {
2199 		.enter = paravirt_enter_lazy_mmu,
2200 		.leave = xen_leave_lazy_mmu,
2201 		.flush = paravirt_flush_lazy_mmu,
2202 	},
2203 
2204 	.set_fixmap = xen_set_fixmap,
2205 };
2206 
2207 void __init xen_init_mmu_ops(void)
2208 {
2209 	x86_init.paging.pagetable_init = xen_pagetable_init;
2210 	pv_mmu_ops = xen_mmu_ops;
2211 
2212 	memset(dummy_mapping, 0xff, PAGE_SIZE);
2213 }
2214 
2215 /* Protected by xen_reservation_lock. */
2216 #define MAX_CONTIG_ORDER 9 /* 2MB */
2217 static unsigned long discontig_frames[1<<MAX_CONTIG_ORDER];
2218 
2219 #define VOID_PTE (mfn_pte(0, __pgprot(0)))
2220 static void xen_zap_pfn_range(unsigned long vaddr, unsigned int order,
2221 				unsigned long *in_frames,
2222 				unsigned long *out_frames)
2223 {
2224 	int i;
2225 	struct multicall_space mcs;
2226 
2227 	xen_mc_batch();
2228 	for (i = 0; i < (1UL<<order); i++, vaddr += PAGE_SIZE) {
2229 		mcs = __xen_mc_entry(0);
2230 
2231 		if (in_frames)
2232 			in_frames[i] = virt_to_mfn(vaddr);
2233 
2234 		MULTI_update_va_mapping(mcs.mc, vaddr, VOID_PTE, 0);
2235 		__set_phys_to_machine(virt_to_pfn(vaddr), INVALID_P2M_ENTRY);
2236 
2237 		if (out_frames)
2238 			out_frames[i] = virt_to_pfn(vaddr);
2239 	}
2240 	xen_mc_issue(0);
2241 }
2242 
2243 /*
2244  * Update the pfn-to-mfn mappings for a virtual address range, either to
2245  * point to an array of mfns, or contiguously from a single starting
2246  * mfn.
2247  */
2248 static void xen_remap_exchanged_ptes(unsigned long vaddr, int order,
2249 				     unsigned long *mfns,
2250 				     unsigned long first_mfn)
2251 {
2252 	unsigned i, limit;
2253 	unsigned long mfn;
2254 
2255 	xen_mc_batch();
2256 
2257 	limit = 1u << order;
2258 	for (i = 0; i < limit; i++, vaddr += PAGE_SIZE) {
2259 		struct multicall_space mcs;
2260 		unsigned flags;
2261 
2262 		mcs = __xen_mc_entry(0);
2263 		if (mfns)
2264 			mfn = mfns[i];
2265 		else
2266 			mfn = first_mfn + i;
2267 
2268 		if (i < (limit - 1))
2269 			flags = 0;
2270 		else {
2271 			if (order == 0)
2272 				flags = UVMF_INVLPG | UVMF_ALL;
2273 			else
2274 				flags = UVMF_TLB_FLUSH | UVMF_ALL;
2275 		}
2276 
2277 		MULTI_update_va_mapping(mcs.mc, vaddr,
2278 				mfn_pte(mfn, PAGE_KERNEL), flags);
2279 
2280 		set_phys_to_machine(virt_to_pfn(vaddr), mfn);
2281 	}
2282 
2283 	xen_mc_issue(0);
2284 }
2285 
2286 /*
2287  * Perform the hypercall to exchange a region of our pfns to point to
2288  * memory with the required contiguous alignment.  Takes the pfns as
2289  * input, and populates mfns as output.
2290  *
2291  * Returns a success code indicating whether the hypervisor was able to
2292  * satisfy the request or not.
2293  */
2294 static int xen_exchange_memory(unsigned long extents_in, unsigned int order_in,
2295 			       unsigned long *pfns_in,
2296 			       unsigned long extents_out,
2297 			       unsigned int order_out,
2298 			       unsigned long *mfns_out,
2299 			       unsigned int address_bits)
2300 {
2301 	long rc;
2302 	int success;
2303 
2304 	struct xen_memory_exchange exchange = {
2305 		.in = {
2306 			.nr_extents   = extents_in,
2307 			.extent_order = order_in,
2308 			.extent_start = pfns_in,
2309 			.domid        = DOMID_SELF
2310 		},
2311 		.out = {
2312 			.nr_extents   = extents_out,
2313 			.extent_order = order_out,
2314 			.extent_start = mfns_out,
2315 			.address_bits = address_bits,
2316 			.domid        = DOMID_SELF
2317 		}
2318 	};
2319 
2320 	BUG_ON(extents_in << order_in != extents_out << order_out);
2321 
2322 	rc = HYPERVISOR_memory_op(XENMEM_exchange, &exchange);
2323 	success = (exchange.nr_exchanged == extents_in);
2324 
2325 	BUG_ON(!success && ((exchange.nr_exchanged != 0) || (rc == 0)));
2326 	BUG_ON(success && (rc != 0));
2327 
2328 	return success;
2329 }
2330 
2331 int xen_create_contiguous_region(unsigned long vstart, unsigned int order,
2332 				 unsigned int address_bits)
2333 {
2334 	unsigned long *in_frames = discontig_frames, out_frame;
2335 	unsigned long  flags;
2336 	int            success;
2337 
2338 	/*
2339 	 * Currently an auto-translated guest will not perform I/O, nor will
2340 	 * it require PAE page directories below 4GB. Therefore any calls to
2341 	 * this function are redundant and can be ignored.
2342 	 */
2343 
2344 	if (xen_feature(XENFEAT_auto_translated_physmap))
2345 		return 0;
2346 
2347 	if (unlikely(order > MAX_CONTIG_ORDER))
2348 		return -ENOMEM;
2349 
2350 	memset((void *) vstart, 0, PAGE_SIZE << order);
2351 
2352 	spin_lock_irqsave(&xen_reservation_lock, flags);
2353 
2354 	/* 1. Zap current PTEs, remembering MFNs. */
2355 	xen_zap_pfn_range(vstart, order, in_frames, NULL);
2356 
2357 	/* 2. Get a new contiguous memory extent. */
2358 	out_frame = virt_to_pfn(vstart);
2359 	success = xen_exchange_memory(1UL << order, 0, in_frames,
2360 				      1, order, &out_frame,
2361 				      address_bits);
2362 
2363 	/* 3. Map the new extent in place of old pages. */
2364 	if (success)
2365 		xen_remap_exchanged_ptes(vstart, order, NULL, out_frame);
2366 	else
2367 		xen_remap_exchanged_ptes(vstart, order, in_frames, 0);
2368 
2369 	spin_unlock_irqrestore(&xen_reservation_lock, flags);
2370 
2371 	return success ? 0 : -ENOMEM;
2372 }
2373 EXPORT_SYMBOL_GPL(xen_create_contiguous_region);
2374 
2375 void xen_destroy_contiguous_region(unsigned long vstart, unsigned int order)
2376 {
2377 	unsigned long *out_frames = discontig_frames, in_frame;
2378 	unsigned long  flags;
2379 	int success;
2380 
2381 	if (xen_feature(XENFEAT_auto_translated_physmap))
2382 		return;
2383 
2384 	if (unlikely(order > MAX_CONTIG_ORDER))
2385 		return;
2386 
2387 	memset((void *) vstart, 0, PAGE_SIZE << order);
2388 
2389 	spin_lock_irqsave(&xen_reservation_lock, flags);
2390 
2391 	/* 1. Find start MFN of contiguous extent. */
2392 	in_frame = virt_to_mfn(vstart);
2393 
2394 	/* 2. Zap current PTEs. */
2395 	xen_zap_pfn_range(vstart, order, NULL, out_frames);
2396 
2397 	/* 3. Do the exchange for non-contiguous MFNs. */
2398 	success = xen_exchange_memory(1, order, &in_frame, 1UL << order,
2399 					0, out_frames, 0);
2400 
2401 	/* 4. Map new pages in place of old pages. */
2402 	if (success)
2403 		xen_remap_exchanged_ptes(vstart, order, out_frames, 0);
2404 	else
2405 		xen_remap_exchanged_ptes(vstart, order, NULL, in_frame);
2406 
2407 	spin_unlock_irqrestore(&xen_reservation_lock, flags);
2408 }
2409 EXPORT_SYMBOL_GPL(xen_destroy_contiguous_region);
2410 
2411 #ifdef CONFIG_XEN_PVHVM
2412 #ifdef CONFIG_PROC_VMCORE
2413 /*
2414  * This function is used in two contexts:
2415  * - the kdump kernel has to check whether a pfn of the crashed kernel
2416  *   was a ballooned page. vmcore is using this function to decide
2417  *   whether to access a pfn of the crashed kernel.
2418  * - the kexec kernel has to check whether a pfn was ballooned by the
2419  *   previous kernel. If the pfn is ballooned, handle it properly.
2420  * Returns 0 if the pfn is not backed by a RAM page, the caller may
2421  * handle the pfn special in this case.
2422  */
2423 static int xen_oldmem_pfn_is_ram(unsigned long pfn)
2424 {
2425 	struct xen_hvm_get_mem_type a = {
2426 		.domid = DOMID_SELF,
2427 		.pfn = pfn,
2428 	};
2429 	int ram;
2430 
2431 	if (HYPERVISOR_hvm_op(HVMOP_get_mem_type, &a))
2432 		return -ENXIO;
2433 
2434 	switch (a.mem_type) {
2435 		case HVMMEM_mmio_dm:
2436 			ram = 0;
2437 			break;
2438 		case HVMMEM_ram_rw:
2439 		case HVMMEM_ram_ro:
2440 		default:
2441 			ram = 1;
2442 			break;
2443 	}
2444 
2445 	return ram;
2446 }
2447 #endif
2448 
2449 static void xen_hvm_exit_mmap(struct mm_struct *mm)
2450 {
2451 	struct xen_hvm_pagetable_dying a;
2452 	int rc;
2453 
2454 	a.domid = DOMID_SELF;
2455 	a.gpa = __pa(mm->pgd);
2456 	rc = HYPERVISOR_hvm_op(HVMOP_pagetable_dying, &a);
2457 	WARN_ON_ONCE(rc < 0);
2458 }
2459 
2460 static int is_pagetable_dying_supported(void)
2461 {
2462 	struct xen_hvm_pagetable_dying a;
2463 	int rc = 0;
2464 
2465 	a.domid = DOMID_SELF;
2466 	a.gpa = 0x00;
2467 	rc = HYPERVISOR_hvm_op(HVMOP_pagetable_dying, &a);
2468 	if (rc < 0) {
2469 		printk(KERN_DEBUG "HVMOP_pagetable_dying not supported\n");
2470 		return 0;
2471 	}
2472 	return 1;
2473 }
2474 
2475 void __init xen_hvm_init_mmu_ops(void)
2476 {
2477 	if (is_pagetable_dying_supported())
2478 		pv_mmu_ops.exit_mmap = xen_hvm_exit_mmap;
2479 #ifdef CONFIG_PROC_VMCORE
2480 	register_oldmem_pfn_is_ram(&xen_oldmem_pfn_is_ram);
2481 #endif
2482 }
2483 #endif
2484 
2485 #define REMAP_BATCH_SIZE 16
2486 
2487 struct remap_data {
2488 	unsigned long mfn;
2489 	pgprot_t prot;
2490 	struct mmu_update *mmu_update;
2491 };
2492 
2493 static int remap_area_mfn_pte_fn(pte_t *ptep, pgtable_t token,
2494 				 unsigned long addr, void *data)
2495 {
2496 	struct remap_data *rmd = data;
2497 	pte_t pte = pte_mkspecial(pfn_pte(rmd->mfn++, rmd->prot));
2498 
2499 	rmd->mmu_update->ptr = virt_to_machine(ptep).maddr;
2500 	rmd->mmu_update->val = pte_val_ma(pte);
2501 	rmd->mmu_update++;
2502 
2503 	return 0;
2504 }
2505 
2506 int xen_remap_domain_mfn_range(struct vm_area_struct *vma,
2507 			       unsigned long addr,
2508 			       xen_pfn_t mfn, int nr,
2509 			       pgprot_t prot, unsigned domid,
2510 			       struct page **pages)
2511 
2512 {
2513 	struct remap_data rmd;
2514 	struct mmu_update mmu_update[REMAP_BATCH_SIZE];
2515 	int batch;
2516 	unsigned long range;
2517 	int err = 0;
2518 
2519 	if (xen_feature(XENFEAT_auto_translated_physmap))
2520 		return -EINVAL;
2521 
2522 	prot = __pgprot(pgprot_val(prot) | _PAGE_IOMAP);
2523 
2524 	BUG_ON(!((vma->vm_flags & (VM_PFNMAP | VM_IO)) == (VM_PFNMAP | VM_IO)));
2525 
2526 	rmd.mfn = mfn;
2527 	rmd.prot = prot;
2528 
2529 	while (nr) {
2530 		batch = min(REMAP_BATCH_SIZE, nr);
2531 		range = (unsigned long)batch << PAGE_SHIFT;
2532 
2533 		rmd.mmu_update = mmu_update;
2534 		err = apply_to_page_range(vma->vm_mm, addr, range,
2535 					  remap_area_mfn_pte_fn, &rmd);
2536 		if (err)
2537 			goto out;
2538 
2539 		err = HYPERVISOR_mmu_update(mmu_update, batch, NULL, domid);
2540 		if (err < 0)
2541 			goto out;
2542 
2543 		nr -= batch;
2544 		addr += range;
2545 	}
2546 
2547 	err = 0;
2548 out:
2549 
2550 	xen_flush_tlb_all();
2551 
2552 	return err;
2553 }
2554 EXPORT_SYMBOL_GPL(xen_remap_domain_mfn_range);
2555 
2556 /* Returns: 0 success */
2557 int xen_unmap_domain_mfn_range(struct vm_area_struct *vma,
2558 			       int numpgs, struct page **pages)
2559 {
2560 	if (!pages || !xen_feature(XENFEAT_auto_translated_physmap))
2561 		return 0;
2562 
2563 	return -EINVAL;
2564 }
2565 EXPORT_SYMBOL_GPL(xen_unmap_domain_mfn_range);
2566