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.
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.
14 * p2m_mid_mfn p2m_mid_mfn
18 * The p2m_mid_mfn pages are mapped by p2m_top_mfn_p.
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
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.
28 * In short, these structures contain the Machine Frame Number (MFN) of the PFN.
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.
38 * We also have the possibility of setting 1-1 mappings on certain regions, so
40 * pfn_to_mfn(0xc0000)=0xc0000
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.
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).
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).
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.
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>
71 #include <asm/cache.h>
72 #include <asm/setup.h>
73 #include <asm/uaccess.h>
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>
82 #include "multicalls.h"
85 #define PMDS_PER_MID_PAGE (P2M_MID_PER_PAGE / PTRS_PER_PTE)
87 unsigned long *xen_p2m_addr __read_mostly;
88 EXPORT_SYMBOL_GPL(xen_p2m_addr);
89 unsigned long xen_p2m_size __read_mostly;
90 EXPORT_SYMBOL_GPL(xen_p2m_size);
91 unsigned long xen_max_p2m_pfn __read_mostly;
92 EXPORT_SYMBOL_GPL(xen_max_p2m_pfn);
94 static DEFINE_SPINLOCK(p2m_update_lock);
96 static unsigned long *p2m_mid_missing_mfn;
97 static unsigned long *p2m_top_mfn;
98 static unsigned long **p2m_top_mfn_p;
99 static unsigned long *p2m_missing;
100 static unsigned long *p2m_identity;
101 static pte_t *p2m_missing_pte;
102 static pte_t *p2m_identity_pte;
104 static inline unsigned p2m_top_index(unsigned long pfn)
106 BUG_ON(pfn >= MAX_P2M_PFN);
107 return pfn / (P2M_MID_PER_PAGE * P2M_PER_PAGE);
110 static inline unsigned p2m_mid_index(unsigned long pfn)
112 return (pfn / P2M_PER_PAGE) % P2M_MID_PER_PAGE;
115 static inline unsigned p2m_index(unsigned long pfn)
117 return pfn % P2M_PER_PAGE;
120 static void p2m_top_mfn_init(unsigned long *top)
124 for (i = 0; i < P2M_TOP_PER_PAGE; i++)
125 top[i] = virt_to_mfn(p2m_mid_missing_mfn);
128 static void p2m_top_mfn_p_init(unsigned long **top)
132 for (i = 0; i < P2M_TOP_PER_PAGE; i++)
133 top[i] = p2m_mid_missing_mfn;
136 static void p2m_mid_mfn_init(unsigned long *mid, unsigned long *leaf)
140 for (i = 0; i < P2M_MID_PER_PAGE; i++)
141 mid[i] = virt_to_mfn(leaf);
144 static void p2m_init(unsigned long *p2m)
148 for (i = 0; i < P2M_PER_PAGE; i++)
149 p2m[i] = INVALID_P2M_ENTRY;
152 static void p2m_init_identity(unsigned long *p2m, unsigned long pfn)
156 for (i = 0; i < P2M_PER_PAGE; i++)
157 p2m[i] = IDENTITY_FRAME(pfn + i);
160 static void * __ref alloc_p2m_page(void)
162 if (unlikely(!slab_is_available()))
163 return alloc_bootmem_align(PAGE_SIZE, PAGE_SIZE);
165 return (void *)__get_free_page(GFP_KERNEL | __GFP_REPEAT);
168 static void __ref free_p2m_page(void *p)
170 if (unlikely(!slab_is_available())) {
171 free_bootmem((unsigned long)p, PAGE_SIZE);
175 free_page((unsigned long)p);
179 * Build the parallel p2m_top_mfn and p2m_mid_mfn structures
181 * This is called both at boot time, and after resuming from suspend:
182 * - At boot time we're called rather early, and must use alloc_bootmem*()
183 * to allocate memory.
185 * - After resume we're called from within stop_machine, but the mfn
186 * tree should already be completely allocated.
188 void __ref xen_build_mfn_list_list(void)
190 unsigned long pfn, mfn;
192 unsigned int level, topidx, mididx;
193 unsigned long *mid_mfn_p;
195 if (xen_feature(XENFEAT_auto_translated_physmap))
198 /* Pre-initialize p2m_top_mfn to be completely missing */
199 if (p2m_top_mfn == NULL) {
200 p2m_mid_missing_mfn = alloc_p2m_page();
201 p2m_mid_mfn_init(p2m_mid_missing_mfn, p2m_missing);
203 p2m_top_mfn_p = alloc_p2m_page();
204 p2m_top_mfn_p_init(p2m_top_mfn_p);
206 p2m_top_mfn = alloc_p2m_page();
207 p2m_top_mfn_init(p2m_top_mfn);
209 /* Reinitialise, mfn's all change after migration */
210 p2m_mid_mfn_init(p2m_mid_missing_mfn, p2m_missing);
213 for (pfn = 0; pfn < xen_max_p2m_pfn && pfn < MAX_P2M_PFN;
214 pfn += P2M_PER_PAGE) {
215 topidx = p2m_top_index(pfn);
216 mididx = p2m_mid_index(pfn);
218 mid_mfn_p = p2m_top_mfn_p[topidx];
219 ptep = lookup_address((unsigned long)(xen_p2m_addr + pfn),
221 BUG_ON(!ptep || level != PG_LEVEL_4K);
222 mfn = pte_mfn(*ptep);
223 ptep = (pte_t *)((unsigned long)ptep & ~(PAGE_SIZE - 1));
225 /* Don't bother allocating any mfn mid levels if
226 * they're just missing, just update the stored mfn,
227 * since all could have changed over a migrate.
229 if (ptep == p2m_missing_pte || ptep == p2m_identity_pte) {
231 BUG_ON(mid_mfn_p != p2m_mid_missing_mfn);
232 p2m_top_mfn[topidx] = virt_to_mfn(p2m_mid_missing_mfn);
233 pfn += (P2M_MID_PER_PAGE - 1) * P2M_PER_PAGE;
237 if (mid_mfn_p == p2m_mid_missing_mfn) {
238 mid_mfn_p = alloc_p2m_page();
239 p2m_mid_mfn_init(mid_mfn_p, p2m_missing);
241 p2m_top_mfn_p[topidx] = mid_mfn_p;
244 p2m_top_mfn[topidx] = virt_to_mfn(mid_mfn_p);
245 mid_mfn_p[mididx] = mfn;
249 void xen_setup_mfn_list_list(void)
251 if (xen_feature(XENFEAT_auto_translated_physmap))
254 BUG_ON(HYPERVISOR_shared_info == &xen_dummy_shared_info);
256 HYPERVISOR_shared_info->arch.pfn_to_mfn_frame_list_list =
257 virt_to_mfn(p2m_top_mfn);
258 HYPERVISOR_shared_info->arch.max_pfn = xen_max_p2m_pfn;
261 /* Set up p2m_top to point to the domain-builder provided p2m pages */
262 void __init xen_build_dynamic_phys_to_machine(void)
266 if (xen_feature(XENFEAT_auto_translated_physmap))
269 xen_p2m_addr = (unsigned long *)xen_start_info->mfn_list;
270 xen_p2m_size = ALIGN(xen_start_info->nr_pages, P2M_PER_PAGE);
272 for (pfn = xen_start_info->nr_pages; pfn < xen_p2m_size; pfn++)
273 xen_p2m_addr[pfn] = INVALID_P2M_ENTRY;
275 xen_max_p2m_pfn = xen_p2m_size;
278 #define P2M_TYPE_IDENTITY 0
279 #define P2M_TYPE_MISSING 1
280 #define P2M_TYPE_PFN 2
281 #define P2M_TYPE_UNKNOWN 3
283 static int xen_p2m_elem_type(unsigned long pfn)
287 if (pfn >= xen_p2m_size)
288 return P2M_TYPE_IDENTITY;
290 mfn = xen_p2m_addr[pfn];
292 if (mfn == INVALID_P2M_ENTRY)
293 return P2M_TYPE_MISSING;
295 if (mfn & IDENTITY_FRAME_BIT)
296 return P2M_TYPE_IDENTITY;
301 static void __init xen_rebuild_p2m_list(unsigned long *p2m)
303 unsigned int i, chunk;
310 p2m_missing = alloc_p2m_page();
311 p2m_init(p2m_missing);
312 p2m_identity = alloc_p2m_page();
313 p2m_init(p2m_identity);
315 p2m_missing_pte = alloc_p2m_page();
316 paravirt_alloc_pte(&init_mm, __pa(p2m_missing_pte) >> PAGE_SHIFT);
317 p2m_identity_pte = alloc_p2m_page();
318 paravirt_alloc_pte(&init_mm, __pa(p2m_identity_pte) >> PAGE_SHIFT);
319 for (i = 0; i < PTRS_PER_PTE; i++) {
320 set_pte(p2m_missing_pte + i,
321 pfn_pte(PFN_DOWN(__pa(p2m_missing)), PAGE_KERNEL_RO));
322 set_pte(p2m_identity_pte + i,
323 pfn_pte(PFN_DOWN(__pa(p2m_identity)), PAGE_KERNEL_RO));
326 for (pfn = 0; pfn < xen_max_p2m_pfn; pfn += chunk) {
328 * Try to map missing/identity PMDs or p2m-pages if possible.
329 * We have to respect the structure of the mfn_list_list
330 * which will be built just afterwards.
331 * Chunk size to test is one p2m page if we are in the middle
332 * of a mfn_list_list mid page and the complete mid page area
333 * if we are at index 0 of the mid page. Please note that a
334 * mid page might cover more than one PMD, e.g. on 32 bit PAE
337 chunk = (pfn & (P2M_PER_PAGE * P2M_MID_PER_PAGE - 1)) ?
338 P2M_PER_PAGE : P2M_PER_PAGE * P2M_MID_PER_PAGE;
340 type = xen_p2m_elem_type(pfn);
342 if (type != P2M_TYPE_PFN)
343 for (i = 1; i < chunk; i++)
344 if (xen_p2m_elem_type(pfn + i) != type)
347 /* Reset to minimal chunk size. */
348 chunk = P2M_PER_PAGE;
350 if (type == P2M_TYPE_PFN || i < chunk) {
351 /* Use initial p2m page contents. */
353 mfns = alloc_p2m_page();
354 copy_page(mfns, xen_p2m_addr + pfn);
356 mfns = xen_p2m_addr + pfn;
358 ptep = populate_extra_pte((unsigned long)(p2m + pfn));
360 pfn_pte(PFN_DOWN(__pa(mfns)), PAGE_KERNEL));
364 if (chunk == P2M_PER_PAGE) {
365 /* Map complete missing or identity p2m-page. */
366 mfns = (type == P2M_TYPE_MISSING) ?
367 p2m_missing : p2m_identity;
368 ptep = populate_extra_pte((unsigned long)(p2m + pfn));
370 pfn_pte(PFN_DOWN(__pa(mfns)), PAGE_KERNEL_RO));
374 /* Complete missing or identity PMD(s) can be mapped. */
375 ptep = (type == P2M_TYPE_MISSING) ?
376 p2m_missing_pte : p2m_identity_pte;
377 for (i = 0; i < PMDS_PER_MID_PAGE; i++) {
378 pmdp = populate_extra_pmd(
379 (unsigned long)(p2m + pfn) + i * PMD_SIZE);
380 set_pmd(pmdp, __pmd(__pa(ptep) | _KERNPG_TABLE));
385 void __init xen_vmalloc_p2m_tree(void)
387 static struct vm_struct vm;
390 vm.size = ALIGN(sizeof(unsigned long) * xen_max_p2m_pfn,
391 PMD_SIZE * PMDS_PER_MID_PAGE);
392 vm_area_register_early(&vm, PMD_SIZE * PMDS_PER_MID_PAGE);
393 pr_notice("p2m virtual area at %p, size is %lx\n", vm.addr, vm.size);
395 xen_max_p2m_pfn = vm.size / sizeof(unsigned long);
397 xen_rebuild_p2m_list(vm.addr);
399 xen_p2m_addr = vm.addr;
400 xen_p2m_size = xen_max_p2m_pfn;
405 unsigned long get_phys_to_machine(unsigned long pfn)
410 if (unlikely(pfn >= xen_p2m_size)) {
411 if (pfn < xen_max_p2m_pfn)
412 return xen_chk_extra_mem(pfn);
414 return IDENTITY_FRAME(pfn);
417 ptep = lookup_address((unsigned long)(xen_p2m_addr + pfn), &level);
418 BUG_ON(!ptep || level != PG_LEVEL_4K);
421 * The INVALID_P2M_ENTRY is filled in both p2m_*identity
422 * and in p2m_*missing, so returning the INVALID_P2M_ENTRY
425 if (pte_pfn(*ptep) == PFN_DOWN(__pa(p2m_identity)))
426 return IDENTITY_FRAME(pfn);
428 return xen_p2m_addr[pfn];
430 EXPORT_SYMBOL_GPL(get_phys_to_machine);
433 * Allocate new pmd(s). It is checked whether the old pmd is still in place.
434 * If not, nothing is changed. This is okay as the only reason for allocating
435 * a new pmd is to replace p2m_missing_pte or p2m_identity_pte by a individual
436 * pmd. In case of PAE/x86-32 there are multiple pmds to allocate!
438 static pte_t *alloc_p2m_pmd(unsigned long addr, pte_t *pte_pg)
441 pte_t *pte_newpg[PMDS_PER_MID_PAGE];
448 /* Do all allocations first to bail out in error case. */
449 for (i = 0; i < PMDS_PER_MID_PAGE; i++) {
450 pte_newpg[i] = alloc_p2m_page();
452 for (i--; i >= 0; i--)
453 free_p2m_page(pte_newpg[i]);
459 vaddr = addr & ~(PMD_SIZE * PMDS_PER_MID_PAGE - 1);
461 for (i = 0; i < PMDS_PER_MID_PAGE; i++) {
462 copy_page(pte_newpg[i], pte_pg);
463 paravirt_alloc_pte(&init_mm, __pa(pte_newpg[i]) >> PAGE_SHIFT);
465 pmdp = lookup_pmd_address(vaddr);
468 spin_lock_irqsave(&p2m_update_lock, flags);
470 ptechk = lookup_address(vaddr, &level);
471 if (ptechk == pte_pg) {
473 __pmd(__pa(pte_newpg[i]) | _KERNPG_TABLE));
477 spin_unlock_irqrestore(&p2m_update_lock, flags);
480 paravirt_release_pte(__pa(pte_newpg[i]) >> PAGE_SHIFT);
481 free_p2m_page(pte_newpg[i]);
487 return lookup_address(addr, &level);
491 * Fully allocate the p2m structure for a given pfn. We need to check
492 * that both the top and mid levels are allocated, and make sure the
493 * parallel mfn tree is kept in sync. We may race with other cpus, so
494 * the new pages are installed with cmpxchg; if we lose the race then
495 * simply free the page we allocated and use the one that's there.
497 static bool alloc_p2m(unsigned long pfn)
499 unsigned topidx, mididx;
500 unsigned long *top_mfn_p, *mid_mfn;
501 pte_t *ptep, *pte_pg;
504 unsigned long addr = (unsigned long)(xen_p2m_addr + pfn);
505 unsigned long p2m_pfn;
507 topidx = p2m_top_index(pfn);
508 mididx = p2m_mid_index(pfn);
510 ptep = lookup_address(addr, &level);
511 BUG_ON(!ptep || level != PG_LEVEL_4K);
512 pte_pg = (pte_t *)((unsigned long)ptep & ~(PAGE_SIZE - 1));
514 if (pte_pg == p2m_missing_pte || pte_pg == p2m_identity_pte) {
515 /* PMD level is missing, allocate a new one */
516 ptep = alloc_p2m_pmd(addr, pte_pg);
522 top_mfn_p = &p2m_top_mfn[topidx];
523 mid_mfn = ACCESS_ONCE(p2m_top_mfn_p[topidx]);
525 BUG_ON(virt_to_mfn(mid_mfn) != *top_mfn_p);
527 if (mid_mfn == p2m_mid_missing_mfn) {
528 /* Separately check the mid mfn level */
529 unsigned long missing_mfn;
530 unsigned long mid_mfn_mfn;
531 unsigned long old_mfn;
533 mid_mfn = alloc_p2m_page();
537 p2m_mid_mfn_init(mid_mfn, p2m_missing);
539 missing_mfn = virt_to_mfn(p2m_mid_missing_mfn);
540 mid_mfn_mfn = virt_to_mfn(mid_mfn);
541 old_mfn = cmpxchg(top_mfn_p, missing_mfn, mid_mfn_mfn);
542 if (old_mfn != missing_mfn) {
543 free_p2m_page(mid_mfn);
544 mid_mfn = mfn_to_virt(old_mfn);
546 p2m_top_mfn_p[topidx] = mid_mfn;
553 p2m_pfn = pte_pfn(ACCESS_ONCE(*ptep));
554 if (p2m_pfn == PFN_DOWN(__pa(p2m_identity)) ||
555 p2m_pfn == PFN_DOWN(__pa(p2m_missing))) {
556 /* p2m leaf page is missing */
559 p2m = alloc_p2m_page();
563 if (p2m_pfn == PFN_DOWN(__pa(p2m_missing)))
566 p2m_init_identity(p2m, pfn);
568 spin_lock_irqsave(&p2m_update_lock, flags);
570 if (pte_pfn(*ptep) == p2m_pfn) {
572 pfn_pte(PFN_DOWN(__pa(p2m)), PAGE_KERNEL));
574 mid_mfn[mididx] = virt_to_mfn(p2m);
578 spin_unlock_irqrestore(&p2m_update_lock, flags);
587 unsigned long __init set_phys_range_identity(unsigned long pfn_s,
592 if (unlikely(pfn_s >= xen_p2m_size))
595 if (unlikely(xen_feature(XENFEAT_auto_translated_physmap)))
596 return pfn_e - pfn_s;
601 if (pfn_e > xen_p2m_size)
602 pfn_e = xen_p2m_size;
604 for (pfn = pfn_s; pfn < pfn_e; pfn++)
605 xen_p2m_addr[pfn] = IDENTITY_FRAME(pfn);
610 bool __set_phys_to_machine(unsigned long pfn, unsigned long mfn)
615 /* don't track P2M changes in autotranslate guests */
616 if (unlikely(xen_feature(XENFEAT_auto_translated_physmap)))
619 if (unlikely(pfn >= xen_p2m_size)) {
620 BUG_ON(mfn != INVALID_P2M_ENTRY);
624 if (likely(!xen_safe_write_ulong(xen_p2m_addr + pfn, mfn)))
627 ptep = lookup_address((unsigned long)(xen_p2m_addr + pfn), &level);
628 BUG_ON(!ptep || level != PG_LEVEL_4K);
630 if (pte_pfn(*ptep) == PFN_DOWN(__pa(p2m_missing)))
631 return mfn == INVALID_P2M_ENTRY;
633 if (pte_pfn(*ptep) == PFN_DOWN(__pa(p2m_identity)))
634 return mfn == IDENTITY_FRAME(pfn);
639 bool set_phys_to_machine(unsigned long pfn, unsigned long mfn)
641 if (unlikely(!__set_phys_to_machine(pfn, mfn))) {
645 return __set_phys_to_machine(pfn, mfn);
651 int set_foreign_p2m_mapping(struct gnttab_map_grant_ref *map_ops,
652 struct gnttab_map_grant_ref *kmap_ops,
653 struct page **pages, unsigned int count)
658 if (xen_feature(XENFEAT_auto_translated_physmap))
662 ret = HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref,
668 for (i = 0; i < count; i++) {
669 unsigned long mfn, pfn;
671 /* Do not add to override if the map failed. */
672 if (map_ops[i].status)
675 if (map_ops[i].flags & GNTMAP_contains_pte) {
676 pte = (pte_t *)(mfn_to_virt(PFN_DOWN(map_ops[i].host_addr)) +
677 (map_ops[i].host_addr & ~PAGE_MASK));
680 mfn = PFN_DOWN(map_ops[i].dev_bus_addr);
682 pfn = page_to_pfn(pages[i]);
684 WARN(pfn_to_mfn(pfn) != INVALID_P2M_ENTRY, "page must be ballooned");
686 if (unlikely(!set_phys_to_machine(pfn, FOREIGN_FRAME(mfn)))) {
695 EXPORT_SYMBOL_GPL(set_foreign_p2m_mapping);
697 int clear_foreign_p2m_mapping(struct gnttab_unmap_grant_ref *unmap_ops,
698 struct gnttab_unmap_grant_ref *kunmap_ops,
699 struct page **pages, unsigned int count)
703 if (xen_feature(XENFEAT_auto_translated_physmap))
706 for (i = 0; i < count; i++) {
707 unsigned long mfn = __pfn_to_mfn(page_to_pfn(pages[i]));
708 unsigned long pfn = page_to_pfn(pages[i]);
710 if (mfn == INVALID_P2M_ENTRY || !(mfn & FOREIGN_FRAME_BIT)) {
715 set_phys_to_machine(pfn, INVALID_P2M_ENTRY);
718 ret = HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref,
723 EXPORT_SYMBOL_GPL(clear_foreign_p2m_mapping);
725 #ifdef CONFIG_XEN_DEBUG_FS
726 #include <linux/debugfs.h>
728 static int p2m_dump_show(struct seq_file *m, void *v)
730 static const char * const type_name[] = {
731 [P2M_TYPE_IDENTITY] = "identity",
732 [P2M_TYPE_MISSING] = "missing",
733 [P2M_TYPE_PFN] = "pfn",
734 [P2M_TYPE_UNKNOWN] = "abnormal"};
735 unsigned long pfn, first_pfn;
738 prev_type = xen_p2m_elem_type(0);
741 for (pfn = 0; pfn < xen_p2m_size; pfn++) {
742 type = xen_p2m_elem_type(pfn);
743 if (type != prev_type) {
744 seq_printf(m, " [0x%lx->0x%lx] %s\n", first_pfn, pfn,
745 type_name[prev_type]);
750 seq_printf(m, " [0x%lx->0x%lx] %s\n", first_pfn, pfn,
751 type_name[prev_type]);
755 static int p2m_dump_open(struct inode *inode, struct file *filp)
757 return single_open(filp, p2m_dump_show, NULL);
760 static const struct file_operations p2m_dump_fops = {
761 .open = p2m_dump_open,
764 .release = single_release,
767 static struct dentry *d_mmu_debug;
769 static int __init xen_p2m_debugfs(void)
771 struct dentry *d_xen = xen_init_debugfs();
776 d_mmu_debug = debugfs_create_dir("mmu", d_xen);
778 debugfs_create_file("p2m", 0600, d_mmu_debug, NULL, &p2m_dump_fops);
781 fs_initcall(xen_p2m_debugfs);
782 #endif /* CONFIG_XEN_DEBUG_FS */