1/*
2 * Xen leaves the responsibility for maintaining p2m mappings to the
3 * guests themselves, but it must also access and update the p2m array
4 * during suspend/resume when all the pages are reallocated.
5 *
6 * The logical flat p2m table is mapped to a linear kernel memory area.
7 * For accesses by Xen a three-level tree linked via mfns only is set up to
8 * allow the address space to be sparse.
9 *
10 *               Xen
11 *                |
12 *          p2m_top_mfn
13 *              /   \
14 * p2m_mid_mfn p2m_mid_mfn
15 *         /           /
16 *  p2m p2m p2m ...
17 *
18 * The p2m_mid_mfn pages are mapped by p2m_top_mfn_p.
19 *
20 * The p2m_top_mfn level is limited to 1 page, so the maximum representable
21 * pseudo-physical address space is:
22 *  P2M_TOP_PER_PAGE * P2M_MID_PER_PAGE * P2M_PER_PAGE pages
23 *
24 * P2M_PER_PAGE depends on the architecture, as a mfn is always
25 * unsigned long (8 bytes on 64-bit, 4 bytes on 32), leading to
26 * 512 and 1024 entries respectively.
27 *
28 * In short, these structures contain the Machine Frame Number (MFN) of the PFN.
29 *
30 * However not all entries are filled with MFNs. Specifically for all other
31 * leaf entries, or for the top  root, or middle one, for which there is a void
32 * entry, we assume it is  "missing". So (for example)
33 *  pfn_to_mfn(0x90909090)=INVALID_P2M_ENTRY.
34 * We have a dedicated page p2m_missing with all entries being
35 * INVALID_P2M_ENTRY. This page may be referenced multiple times in the p2m
36 * list/tree in case there are multiple areas with P2M_PER_PAGE invalid pfns.
37 *
38 * We also have the possibility of setting 1-1 mappings on certain regions, so
39 * that:
40 *  pfn_to_mfn(0xc0000)=0xc0000
41 *
42 * The benefit of this is, that we can assume for non-RAM regions (think
43 * PCI BARs, or ACPI spaces), we can create mappings easily because we
44 * get the PFN value to match the MFN.
45 *
46 * For this to work efficiently we have one new page p2m_identity. All entries
47 * in p2m_identity are set to INVALID_P2M_ENTRY type (Xen toolstack only
48 * recognizes that and MFNs, no other fancy value).
49 *
50 * On lookup we spot that the entry points to p2m_identity and return the
51 * identity value instead of dereferencing and returning INVALID_P2M_ENTRY.
52 * If the entry points to an allocated page, we just proceed as before and
53 * return the PFN. If the PFN has IDENTITY_FRAME_BIT set we unmask that in
54 * appropriate functions (pfn_to_mfn).
55 *
56 * The reason for having the IDENTITY_FRAME_BIT instead of just returning the
57 * PFN is that we could find ourselves where pfn_to_mfn(pfn)==pfn for a
58 * non-identity pfn. To protect ourselves against we elect to set (and get) the
59 * IDENTITY_FRAME_BIT on all identity mapped PFNs.
60 */
61
62#include <linux/init.h>
63#include <linux/module.h>
64#include <linux/list.h>
65#include <linux/hash.h>
66#include <linux/sched.h>
67#include <linux/seq_file.h>
68#include <linux/bootmem.h>
69#include <linux/slab.h>
70
71#include <asm/cache.h>
72#include <asm/setup.h>
73#include <asm/uaccess.h>
74
75#include <asm/xen/page.h>
76#include <asm/xen/hypercall.h>
77#include <asm/xen/hypervisor.h>
78#include <xen/balloon.h>
79#include <xen/grant_table.h>
80
81#include "p2m.h"
82#include "multicalls.h"
83#include "xen-ops.h"
84
85#define PMDS_PER_MID_PAGE	(P2M_MID_PER_PAGE / PTRS_PER_PTE)
86
87unsigned long *xen_p2m_addr __read_mostly;
88EXPORT_SYMBOL_GPL(xen_p2m_addr);
89unsigned long xen_p2m_size __read_mostly;
90EXPORT_SYMBOL_GPL(xen_p2m_size);
91unsigned long xen_max_p2m_pfn __read_mostly;
92EXPORT_SYMBOL_GPL(xen_max_p2m_pfn);
93
94#ifdef CONFIG_XEN_BALLOON_MEMORY_HOTPLUG_LIMIT
95#define P2M_LIMIT CONFIG_XEN_BALLOON_MEMORY_HOTPLUG_LIMIT
96#else
97#define P2M_LIMIT 0
98#endif
99
100static DEFINE_SPINLOCK(p2m_update_lock);
101
102static unsigned long *p2m_mid_missing_mfn;
103static unsigned long *p2m_top_mfn;
104static unsigned long **p2m_top_mfn_p;
105static unsigned long *p2m_missing;
106static unsigned long *p2m_identity;
107static pte_t *p2m_missing_pte;
108static pte_t *p2m_identity_pte;
109
110static inline unsigned p2m_top_index(unsigned long pfn)
111{
112	BUG_ON(pfn >= MAX_P2M_PFN);
113	return pfn / (P2M_MID_PER_PAGE * P2M_PER_PAGE);
114}
115
116static inline unsigned p2m_mid_index(unsigned long pfn)
117{
118	return (pfn / P2M_PER_PAGE) % P2M_MID_PER_PAGE;
119}
120
121static inline unsigned p2m_index(unsigned long pfn)
122{
123	return pfn % P2M_PER_PAGE;
124}
125
126static void p2m_top_mfn_init(unsigned long *top)
127{
128	unsigned i;
129
130	for (i = 0; i < P2M_TOP_PER_PAGE; i++)
131		top[i] = virt_to_mfn(p2m_mid_missing_mfn);
132}
133
134static void p2m_top_mfn_p_init(unsigned long **top)
135{
136	unsigned i;
137
138	for (i = 0; i < P2M_TOP_PER_PAGE; i++)
139		top[i] = p2m_mid_missing_mfn;
140}
141
142static void p2m_mid_mfn_init(unsigned long *mid, unsigned long *leaf)
143{
144	unsigned i;
145
146	for (i = 0; i < P2M_MID_PER_PAGE; i++)
147		mid[i] = virt_to_mfn(leaf);
148}
149
150static void p2m_init(unsigned long *p2m)
151{
152	unsigned i;
153
154	for (i = 0; i < P2M_PER_PAGE; i++)
155		p2m[i] = INVALID_P2M_ENTRY;
156}
157
158static void p2m_init_identity(unsigned long *p2m, unsigned long pfn)
159{
160	unsigned i;
161
162	for (i = 0; i < P2M_PER_PAGE; i++)
163		p2m[i] = IDENTITY_FRAME(pfn + i);
164}
165
166static void * __ref alloc_p2m_page(void)
167{
168	if (unlikely(!slab_is_available()))
169		return alloc_bootmem_align(PAGE_SIZE, PAGE_SIZE);
170
171	return (void *)__get_free_page(GFP_KERNEL | __GFP_REPEAT);
172}
173
174static void __ref free_p2m_page(void *p)
175{
176	if (unlikely(!slab_is_available())) {
177		free_bootmem((unsigned long)p, PAGE_SIZE);
178		return;
179	}
180
181	free_page((unsigned long)p);
182}
183
184/*
185 * Build the parallel p2m_top_mfn and p2m_mid_mfn structures
186 *
187 * This is called both at boot time, and after resuming from suspend:
188 * - At boot time we're called rather early, and must use alloc_bootmem*()
189 *   to allocate memory.
190 *
191 * - After resume we're called from within stop_machine, but the mfn
192 *   tree should already be completely allocated.
193 */
194void __ref xen_build_mfn_list_list(void)
195{
196	unsigned long pfn, mfn;
197	pte_t *ptep;
198	unsigned int level, topidx, mididx;
199	unsigned long *mid_mfn_p;
200
201	if (xen_feature(XENFEAT_auto_translated_physmap))
202		return;
203
204	/* Pre-initialize p2m_top_mfn to be completely missing */
205	if (p2m_top_mfn == NULL) {
206		p2m_mid_missing_mfn = alloc_p2m_page();
207		p2m_mid_mfn_init(p2m_mid_missing_mfn, p2m_missing);
208
209		p2m_top_mfn_p = alloc_p2m_page();
210		p2m_top_mfn_p_init(p2m_top_mfn_p);
211
212		p2m_top_mfn = alloc_p2m_page();
213		p2m_top_mfn_init(p2m_top_mfn);
214	} else {
215		/* Reinitialise, mfn's all change after migration */
216		p2m_mid_mfn_init(p2m_mid_missing_mfn, p2m_missing);
217	}
218
219	for (pfn = 0; pfn < xen_max_p2m_pfn && pfn < MAX_P2M_PFN;
220	     pfn += P2M_PER_PAGE) {
221		topidx = p2m_top_index(pfn);
222		mididx = p2m_mid_index(pfn);
223
224		mid_mfn_p = p2m_top_mfn_p[topidx];
225		ptep = lookup_address((unsigned long)(xen_p2m_addr + pfn),
226				      &level);
227		BUG_ON(!ptep || level != PG_LEVEL_4K);
228		mfn = pte_mfn(*ptep);
229		ptep = (pte_t *)((unsigned long)ptep & ~(PAGE_SIZE - 1));
230
231		/* Don't bother allocating any mfn mid levels if
232		 * they're just missing, just update the stored mfn,
233		 * since all could have changed over a migrate.
234		 */
235		if (ptep == p2m_missing_pte || ptep == p2m_identity_pte) {
236			BUG_ON(mididx);
237			BUG_ON(mid_mfn_p != p2m_mid_missing_mfn);
238			p2m_top_mfn[topidx] = virt_to_mfn(p2m_mid_missing_mfn);
239			pfn += (P2M_MID_PER_PAGE - 1) * P2M_PER_PAGE;
240			continue;
241		}
242
243		if (mid_mfn_p == p2m_mid_missing_mfn) {
244			mid_mfn_p = alloc_p2m_page();
245			p2m_mid_mfn_init(mid_mfn_p, p2m_missing);
246
247			p2m_top_mfn_p[topidx] = mid_mfn_p;
248		}
249
250		p2m_top_mfn[topidx] = virt_to_mfn(mid_mfn_p);
251		mid_mfn_p[mididx] = mfn;
252	}
253}
254
255void xen_setup_mfn_list_list(void)
256{
257	if (xen_feature(XENFEAT_auto_translated_physmap))
258		return;
259
260	BUG_ON(HYPERVISOR_shared_info == &xen_dummy_shared_info);
261
262	HYPERVISOR_shared_info->arch.pfn_to_mfn_frame_list_list =
263		virt_to_mfn(p2m_top_mfn);
264	HYPERVISOR_shared_info->arch.max_pfn = xen_max_p2m_pfn;
265}
266
267/* Set up p2m_top to point to the domain-builder provided p2m pages */
268void __init xen_build_dynamic_phys_to_machine(void)
269{
270	unsigned long pfn;
271
272	 if (xen_feature(XENFEAT_auto_translated_physmap))
273		return;
274
275	xen_p2m_addr = (unsigned long *)xen_start_info->mfn_list;
276	xen_p2m_size = ALIGN(xen_start_info->nr_pages, P2M_PER_PAGE);
277
278	for (pfn = xen_start_info->nr_pages; pfn < xen_p2m_size; pfn++)
279		xen_p2m_addr[pfn] = INVALID_P2M_ENTRY;
280
281	xen_max_p2m_pfn = xen_p2m_size;
282}
283
284#define P2M_TYPE_IDENTITY	0
285#define P2M_TYPE_MISSING	1
286#define P2M_TYPE_PFN		2
287#define P2M_TYPE_UNKNOWN	3
288
289static int xen_p2m_elem_type(unsigned long pfn)
290{
291	unsigned long mfn;
292
293	if (pfn >= xen_p2m_size)
294		return P2M_TYPE_IDENTITY;
295
296	mfn = xen_p2m_addr[pfn];
297
298	if (mfn == INVALID_P2M_ENTRY)
299		return P2M_TYPE_MISSING;
300
301	if (mfn & IDENTITY_FRAME_BIT)
302		return P2M_TYPE_IDENTITY;
303
304	return P2M_TYPE_PFN;
305}
306
307static void __init xen_rebuild_p2m_list(unsigned long *p2m)
308{
309	unsigned int i, chunk;
310	unsigned long pfn;
311	unsigned long *mfns;
312	pte_t *ptep;
313	pmd_t *pmdp;
314	int type;
315
316	p2m_missing = alloc_p2m_page();
317	p2m_init(p2m_missing);
318	p2m_identity = alloc_p2m_page();
319	p2m_init(p2m_identity);
320
321	p2m_missing_pte = alloc_p2m_page();
322	paravirt_alloc_pte(&init_mm, __pa(p2m_missing_pte) >> PAGE_SHIFT);
323	p2m_identity_pte = alloc_p2m_page();
324	paravirt_alloc_pte(&init_mm, __pa(p2m_identity_pte) >> PAGE_SHIFT);
325	for (i = 0; i < PTRS_PER_PTE; i++) {
326		set_pte(p2m_missing_pte + i,
327			pfn_pte(PFN_DOWN(__pa(p2m_missing)), PAGE_KERNEL_RO));
328		set_pte(p2m_identity_pte + i,
329			pfn_pte(PFN_DOWN(__pa(p2m_identity)), PAGE_KERNEL_RO));
330	}
331
332	for (pfn = 0; pfn < xen_max_p2m_pfn; pfn += chunk) {
333		/*
334		 * Try to map missing/identity PMDs or p2m-pages if possible.
335		 * We have to respect the structure of the mfn_list_list
336		 * which will be built just afterwards.
337		 * Chunk size to test is one p2m page if we are in the middle
338		 * of a mfn_list_list mid page and the complete mid page area
339		 * if we are at index 0 of the mid page. Please note that a
340		 * mid page might cover more than one PMD, e.g. on 32 bit PAE
341		 * kernels.
342		 */
343		chunk = (pfn & (P2M_PER_PAGE * P2M_MID_PER_PAGE - 1)) ?
344			P2M_PER_PAGE : P2M_PER_PAGE * P2M_MID_PER_PAGE;
345
346		type = xen_p2m_elem_type(pfn);
347		i = 0;
348		if (type != P2M_TYPE_PFN)
349			for (i = 1; i < chunk; i++)
350				if (xen_p2m_elem_type(pfn + i) != type)
351					break;
352		if (i < chunk)
353			/* Reset to minimal chunk size. */
354			chunk = P2M_PER_PAGE;
355
356		if (type == P2M_TYPE_PFN || i < chunk) {
357			/* Use initial p2m page contents. */
358#ifdef CONFIG_X86_64
359			mfns = alloc_p2m_page();
360			copy_page(mfns, xen_p2m_addr + pfn);
361#else
362			mfns = xen_p2m_addr + pfn;
363#endif
364			ptep = populate_extra_pte((unsigned long)(p2m + pfn));
365			set_pte(ptep,
366				pfn_pte(PFN_DOWN(__pa(mfns)), PAGE_KERNEL));
367			continue;
368		}
369
370		if (chunk == P2M_PER_PAGE) {
371			/* Map complete missing or identity p2m-page. */
372			mfns = (type == P2M_TYPE_MISSING) ?
373				p2m_missing : p2m_identity;
374			ptep = populate_extra_pte((unsigned long)(p2m + pfn));
375			set_pte(ptep,
376				pfn_pte(PFN_DOWN(__pa(mfns)), PAGE_KERNEL_RO));
377			continue;
378		}
379
380		/* Complete missing or identity PMD(s) can be mapped. */
381		ptep = (type == P2M_TYPE_MISSING) ?
382			p2m_missing_pte : p2m_identity_pte;
383		for (i = 0; i < PMDS_PER_MID_PAGE; i++) {
384			pmdp = populate_extra_pmd(
385				(unsigned long)(p2m + pfn) + i * PMD_SIZE);
386			set_pmd(pmdp, __pmd(__pa(ptep) | _KERNPG_TABLE));
387		}
388	}
389}
390
391void __init xen_vmalloc_p2m_tree(void)
392{
393	static struct vm_struct vm;
394	unsigned long p2m_limit;
395
396	p2m_limit = (phys_addr_t)P2M_LIMIT * 1024 * 1024 * 1024 / PAGE_SIZE;
397	vm.flags = VM_ALLOC;
398	vm.size = ALIGN(sizeof(unsigned long) * max(xen_max_p2m_pfn, p2m_limit),
399			PMD_SIZE * PMDS_PER_MID_PAGE);
400	vm_area_register_early(&vm, PMD_SIZE * PMDS_PER_MID_PAGE);
401	pr_notice("p2m virtual area at %p, size is %lx\n", vm.addr, vm.size);
402
403	xen_max_p2m_pfn = vm.size / sizeof(unsigned long);
404
405	xen_rebuild_p2m_list(vm.addr);
406
407	xen_p2m_addr = vm.addr;
408	xen_p2m_size = xen_max_p2m_pfn;
409
410	xen_inv_extra_mem();
411}
412
413unsigned long get_phys_to_machine(unsigned long pfn)
414{
415	pte_t *ptep;
416	unsigned int level;
417
418	if (unlikely(pfn >= xen_p2m_size)) {
419		if (pfn < xen_max_p2m_pfn)
420			return xen_chk_extra_mem(pfn);
421
422		return IDENTITY_FRAME(pfn);
423	}
424
425	ptep = lookup_address((unsigned long)(xen_p2m_addr + pfn), &level);
426	BUG_ON(!ptep || level != PG_LEVEL_4K);
427
428	/*
429	 * The INVALID_P2M_ENTRY is filled in both p2m_*identity
430	 * and in p2m_*missing, so returning the INVALID_P2M_ENTRY
431	 * would be wrong.
432	 */
433	if (pte_pfn(*ptep) == PFN_DOWN(__pa(p2m_identity)))
434		return IDENTITY_FRAME(pfn);
435
436	return xen_p2m_addr[pfn];
437}
438EXPORT_SYMBOL_GPL(get_phys_to_machine);
439
440/*
441 * Allocate new pmd(s). It is checked whether the old pmd is still in place.
442 * If not, nothing is changed. This is okay as the only reason for allocating
443 * a new pmd is to replace p2m_missing_pte or p2m_identity_pte by a individual
444 * pmd. In case of PAE/x86-32 there are multiple pmds to allocate!
445 */
446static pte_t *alloc_p2m_pmd(unsigned long addr, pte_t *pte_pg)
447{
448	pte_t *ptechk;
449	pte_t *pte_newpg[PMDS_PER_MID_PAGE];
450	pmd_t *pmdp;
451	unsigned int level;
452	unsigned long flags;
453	unsigned long vaddr;
454	int i;
455
456	/* Do all allocations first to bail out in error case. */
457	for (i = 0; i < PMDS_PER_MID_PAGE; i++) {
458		pte_newpg[i] = alloc_p2m_page();
459		if (!pte_newpg[i]) {
460			for (i--; i >= 0; i--)
461				free_p2m_page(pte_newpg[i]);
462
463			return NULL;
464		}
465	}
466
467	vaddr = addr & ~(PMD_SIZE * PMDS_PER_MID_PAGE - 1);
468
469	for (i = 0; i < PMDS_PER_MID_PAGE; i++) {
470		copy_page(pte_newpg[i], pte_pg);
471		paravirt_alloc_pte(&init_mm, __pa(pte_newpg[i]) >> PAGE_SHIFT);
472
473		pmdp = lookup_pmd_address(vaddr);
474		BUG_ON(!pmdp);
475
476		spin_lock_irqsave(&p2m_update_lock, flags);
477
478		ptechk = lookup_address(vaddr, &level);
479		if (ptechk == pte_pg) {
480			set_pmd(pmdp,
481				__pmd(__pa(pte_newpg[i]) | _KERNPG_TABLE));
482			pte_newpg[i] = NULL;
483		}
484
485		spin_unlock_irqrestore(&p2m_update_lock, flags);
486
487		if (pte_newpg[i]) {
488			paravirt_release_pte(__pa(pte_newpg[i]) >> PAGE_SHIFT);
489			free_p2m_page(pte_newpg[i]);
490		}
491
492		vaddr += PMD_SIZE;
493	}
494
495	return lookup_address(addr, &level);
496}
497
498/*
499 * Fully allocate the p2m structure for a given pfn.  We need to check
500 * that both the top and mid levels are allocated, and make sure the
501 * parallel mfn tree is kept in sync.  We may race with other cpus, so
502 * the new pages are installed with cmpxchg; if we lose the race then
503 * simply free the page we allocated and use the one that's there.
504 */
505static bool alloc_p2m(unsigned long pfn)
506{
507	unsigned topidx, mididx;
508	unsigned long *top_mfn_p, *mid_mfn;
509	pte_t *ptep, *pte_pg;
510	unsigned int level;
511	unsigned long flags;
512	unsigned long addr = (unsigned long)(xen_p2m_addr + pfn);
513	unsigned long p2m_pfn;
514
515	topidx = p2m_top_index(pfn);
516	mididx = p2m_mid_index(pfn);
517
518	ptep = lookup_address(addr, &level);
519	BUG_ON(!ptep || level != PG_LEVEL_4K);
520	pte_pg = (pte_t *)((unsigned long)ptep & ~(PAGE_SIZE - 1));
521
522	if (pte_pg == p2m_missing_pte || pte_pg == p2m_identity_pte) {
523		/* PMD level is missing, allocate a new one */
524		ptep = alloc_p2m_pmd(addr, pte_pg);
525		if (!ptep)
526			return false;
527	}
528
529	if (p2m_top_mfn) {
530		top_mfn_p = &p2m_top_mfn[topidx];
531		mid_mfn = ACCESS_ONCE(p2m_top_mfn_p[topidx]);
532
533		BUG_ON(virt_to_mfn(mid_mfn) != *top_mfn_p);
534
535		if (mid_mfn == p2m_mid_missing_mfn) {
536			/* Separately check the mid mfn level */
537			unsigned long missing_mfn;
538			unsigned long mid_mfn_mfn;
539			unsigned long old_mfn;
540
541			mid_mfn = alloc_p2m_page();
542			if (!mid_mfn)
543				return false;
544
545			p2m_mid_mfn_init(mid_mfn, p2m_missing);
546
547			missing_mfn = virt_to_mfn(p2m_mid_missing_mfn);
548			mid_mfn_mfn = virt_to_mfn(mid_mfn);
549			old_mfn = cmpxchg(top_mfn_p, missing_mfn, mid_mfn_mfn);
550			if (old_mfn != missing_mfn) {
551				free_p2m_page(mid_mfn);
552				mid_mfn = mfn_to_virt(old_mfn);
553			} else {
554				p2m_top_mfn_p[topidx] = mid_mfn;
555			}
556		}
557	} else {
558		mid_mfn = NULL;
559	}
560
561	p2m_pfn = pte_pfn(READ_ONCE(*ptep));
562	if (p2m_pfn == PFN_DOWN(__pa(p2m_identity)) ||
563	    p2m_pfn == PFN_DOWN(__pa(p2m_missing))) {
564		/* p2m leaf page is missing */
565		unsigned long *p2m;
566
567		p2m = alloc_p2m_page();
568		if (!p2m)
569			return false;
570
571		if (p2m_pfn == PFN_DOWN(__pa(p2m_missing)))
572			p2m_init(p2m);
573		else
574			p2m_init_identity(p2m, pfn & ~(P2M_PER_PAGE - 1));
575
576		spin_lock_irqsave(&p2m_update_lock, flags);
577
578		if (pte_pfn(*ptep) == p2m_pfn) {
579			set_pte(ptep,
580				pfn_pte(PFN_DOWN(__pa(p2m)), PAGE_KERNEL));
581			if (mid_mfn)
582				mid_mfn[mididx] = virt_to_mfn(p2m);
583			p2m = NULL;
584		}
585
586		spin_unlock_irqrestore(&p2m_update_lock, flags);
587
588		if (p2m)
589			free_p2m_page(p2m);
590	}
591
592	return true;
593}
594
595unsigned long __init set_phys_range_identity(unsigned long pfn_s,
596				      unsigned long pfn_e)
597{
598	unsigned long pfn;
599
600	if (unlikely(pfn_s >= xen_p2m_size))
601		return 0;
602
603	if (unlikely(xen_feature(XENFEAT_auto_translated_physmap)))
604		return pfn_e - pfn_s;
605
606	if (pfn_s > pfn_e)
607		return 0;
608
609	if (pfn_e > xen_p2m_size)
610		pfn_e = xen_p2m_size;
611
612	for (pfn = pfn_s; pfn < pfn_e; pfn++)
613		xen_p2m_addr[pfn] = IDENTITY_FRAME(pfn);
614
615	return pfn - pfn_s;
616}
617
618bool __set_phys_to_machine(unsigned long pfn, unsigned long mfn)
619{
620	pte_t *ptep;
621	unsigned int level;
622
623	/* don't track P2M changes in autotranslate guests */
624	if (unlikely(xen_feature(XENFEAT_auto_translated_physmap)))
625		return true;
626
627	if (unlikely(pfn >= xen_p2m_size)) {
628		BUG_ON(mfn != INVALID_P2M_ENTRY);
629		return true;
630	}
631
632	if (likely(!xen_safe_write_ulong(xen_p2m_addr + pfn, mfn)))
633		return true;
634
635	ptep = lookup_address((unsigned long)(xen_p2m_addr + pfn), &level);
636	BUG_ON(!ptep || level != PG_LEVEL_4K);
637
638	if (pte_pfn(*ptep) == PFN_DOWN(__pa(p2m_missing)))
639		return mfn == INVALID_P2M_ENTRY;
640
641	if (pte_pfn(*ptep) == PFN_DOWN(__pa(p2m_identity)))
642		return mfn == IDENTITY_FRAME(pfn);
643
644	return false;
645}
646
647bool set_phys_to_machine(unsigned long pfn, unsigned long mfn)
648{
649	if (unlikely(!__set_phys_to_machine(pfn, mfn))) {
650		if (!alloc_p2m(pfn))
651			return false;
652
653		return __set_phys_to_machine(pfn, mfn);
654	}
655
656	return true;
657}
658
659int set_foreign_p2m_mapping(struct gnttab_map_grant_ref *map_ops,
660			    struct gnttab_map_grant_ref *kmap_ops,
661			    struct page **pages, unsigned int count)
662{
663	int i, ret = 0;
664	pte_t *pte;
665
666	if (xen_feature(XENFEAT_auto_translated_physmap))
667		return 0;
668
669	if (kmap_ops) {
670		ret = HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref,
671						kmap_ops, count);
672		if (ret)
673			goto out;
674	}
675
676	for (i = 0; i < count; i++) {
677		unsigned long mfn, pfn;
678
679		/* Do not add to override if the map failed. */
680		if (map_ops[i].status)
681			continue;
682
683		if (map_ops[i].flags & GNTMAP_contains_pte) {
684			pte = (pte_t *)(mfn_to_virt(PFN_DOWN(map_ops[i].host_addr)) +
685				(map_ops[i].host_addr & ~PAGE_MASK));
686			mfn = pte_mfn(*pte);
687		} else {
688			mfn = PFN_DOWN(map_ops[i].dev_bus_addr);
689		}
690		pfn = page_to_pfn(pages[i]);
691
692		WARN(pfn_to_mfn(pfn) != INVALID_P2M_ENTRY, "page must be ballooned");
693
694		if (unlikely(!set_phys_to_machine(pfn, FOREIGN_FRAME(mfn)))) {
695			ret = -ENOMEM;
696			goto out;
697		}
698	}
699
700out:
701	return ret;
702}
703EXPORT_SYMBOL_GPL(set_foreign_p2m_mapping);
704
705int clear_foreign_p2m_mapping(struct gnttab_unmap_grant_ref *unmap_ops,
706			      struct gnttab_unmap_grant_ref *kunmap_ops,
707			      struct page **pages, unsigned int count)
708{
709	int i, ret = 0;
710
711	if (xen_feature(XENFEAT_auto_translated_physmap))
712		return 0;
713
714	for (i = 0; i < count; i++) {
715		unsigned long mfn = __pfn_to_mfn(page_to_pfn(pages[i]));
716		unsigned long pfn = page_to_pfn(pages[i]);
717
718		if (mfn == INVALID_P2M_ENTRY || !(mfn & FOREIGN_FRAME_BIT)) {
719			ret = -EINVAL;
720			goto out;
721		}
722
723		set_phys_to_machine(pfn, INVALID_P2M_ENTRY);
724	}
725	if (kunmap_ops)
726		ret = HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref,
727						kunmap_ops, count);
728out:
729	return ret;
730}
731EXPORT_SYMBOL_GPL(clear_foreign_p2m_mapping);
732
733#ifdef CONFIG_XEN_DEBUG_FS
734#include <linux/debugfs.h>
735#include "debugfs.h"
736static int p2m_dump_show(struct seq_file *m, void *v)
737{
738	static const char * const type_name[] = {
739				[P2M_TYPE_IDENTITY] = "identity",
740				[P2M_TYPE_MISSING] = "missing",
741				[P2M_TYPE_PFN] = "pfn",
742				[P2M_TYPE_UNKNOWN] = "abnormal"};
743	unsigned long pfn, first_pfn;
744	int type, prev_type;
745
746	prev_type = xen_p2m_elem_type(0);
747	first_pfn = 0;
748
749	for (pfn = 0; pfn < xen_p2m_size; pfn++) {
750		type = xen_p2m_elem_type(pfn);
751		if (type != prev_type) {
752			seq_printf(m, " [0x%lx->0x%lx] %s\n", first_pfn, pfn,
753				   type_name[prev_type]);
754			prev_type = type;
755			first_pfn = pfn;
756		}
757	}
758	seq_printf(m, " [0x%lx->0x%lx] %s\n", first_pfn, pfn,
759		   type_name[prev_type]);
760	return 0;
761}
762
763static int p2m_dump_open(struct inode *inode, struct file *filp)
764{
765	return single_open(filp, p2m_dump_show, NULL);
766}
767
768static const struct file_operations p2m_dump_fops = {
769	.open		= p2m_dump_open,
770	.read		= seq_read,
771	.llseek		= seq_lseek,
772	.release	= single_release,
773};
774
775static struct dentry *d_mmu_debug;
776
777static int __init xen_p2m_debugfs(void)
778{
779	struct dentry *d_xen = xen_init_debugfs();
780
781	if (d_xen == NULL)
782		return -ENOMEM;
783
784	d_mmu_debug = debugfs_create_dir("mmu", d_xen);
785
786	debugfs_create_file("p2m", 0600, d_mmu_debug, NULL, &p2m_dump_fops);
787	return 0;
788}
789fs_initcall(xen_p2m_debugfs);
790#endif /* CONFIG_XEN_DEBUG_FS */
791