1 // SPDX-License-Identifier: GPL-2.0
4 * Xen leaves the responsibility for maintaining p2m mappings to the
5 * guests themselves, but it must also access and update the p2m array
6 * during suspend/resume when all the pages are reallocated.
8 * The logical flat p2m table is mapped to a linear kernel memory area.
9 * For accesses by Xen a three-level tree linked via mfns only is set up to
10 * allow the address space to be sparse.
16 * p2m_mid_mfn p2m_mid_mfn
20 * The p2m_mid_mfn pages are mapped by p2m_top_mfn_p.
22 * The p2m_top_mfn level is limited to 1 page, so the maximum representable
23 * pseudo-physical address space is:
24 * P2M_TOP_PER_PAGE * P2M_MID_PER_PAGE * P2M_PER_PAGE pages
26 * P2M_PER_PAGE depends on the architecture, as a mfn is always
27 * unsigned long (8 bytes on 64-bit, 4 bytes on 32), leading to
28 * 512 and 1024 entries respectively.
30 * In short, these structures contain the Machine Frame Number (MFN) of the PFN.
32 * However not all entries are filled with MFNs. Specifically for all other
33 * leaf entries, or for the top root, or middle one, for which there is a void
34 * entry, we assume it is "missing". So (for example)
35 * pfn_to_mfn(0x90909090)=INVALID_P2M_ENTRY.
36 * We have a dedicated page p2m_missing with all entries being
37 * INVALID_P2M_ENTRY. This page may be referenced multiple times in the p2m
38 * list/tree in case there are multiple areas with P2M_PER_PAGE invalid pfns.
40 * We also have the possibility of setting 1-1 mappings on certain regions, so
42 * pfn_to_mfn(0xc0000)=0xc0000
44 * The benefit of this is, that we can assume for non-RAM regions (think
45 * PCI BARs, or ACPI spaces), we can create mappings easily because we
46 * get the PFN value to match the MFN.
48 * For this to work efficiently we have one new page p2m_identity. All entries
49 * in p2m_identity are set to INVALID_P2M_ENTRY type (Xen toolstack only
50 * recognizes that and MFNs, no other fancy value).
52 * On lookup we spot that the entry points to p2m_identity and return the
53 * identity value instead of dereferencing and returning INVALID_P2M_ENTRY.
54 * If the entry points to an allocated page, we just proceed as before and
55 * return the PFN. If the PFN has IDENTITY_FRAME_BIT set we unmask that in
56 * appropriate functions (pfn_to_mfn).
58 * The reason for having the IDENTITY_FRAME_BIT instead of just returning the
59 * PFN is that we could find ourselves where pfn_to_mfn(pfn)==pfn for a
60 * non-identity pfn. To protect ourselves against we elect to set (and get) the
61 * IDENTITY_FRAME_BIT on all identity mapped PFNs.
64 #include <linux/init.h>
65 #include <linux/export.h>
66 #include <linux/list.h>
67 #include <linux/hash.h>
68 #include <linux/sched.h>
69 #include <linux/seq_file.h>
70 #include <linux/memblock.h>
71 #include <linux/slab.h>
72 #include <linux/vmalloc.h>
74 #include <asm/cache.h>
75 #include <asm/setup.h>
76 #include <linux/uaccess.h>
78 #include <asm/xen/page.h>
79 #include <asm/xen/hypercall.h>
80 #include <asm/xen/hypervisor.h>
81 #include <xen/balloon.h>
82 #include <xen/grant_table.h>
84 #include "multicalls.h"
87 #define P2M_MID_PER_PAGE (PAGE_SIZE / sizeof(unsigned long *))
88 #define P2M_TOP_PER_PAGE (PAGE_SIZE / sizeof(unsigned long **))
90 #define MAX_P2M_PFN (P2M_TOP_PER_PAGE * P2M_MID_PER_PAGE * P2M_PER_PAGE)
92 #define PMDS_PER_MID_PAGE (P2M_MID_PER_PAGE / PTRS_PER_PTE)
94 unsigned long *xen_p2m_addr __read_mostly;
95 EXPORT_SYMBOL_GPL(xen_p2m_addr);
96 unsigned long xen_p2m_size __read_mostly;
97 EXPORT_SYMBOL_GPL(xen_p2m_size);
98 unsigned long xen_max_p2m_pfn __read_mostly;
99 EXPORT_SYMBOL_GPL(xen_max_p2m_pfn);
101 #ifdef CONFIG_XEN_BALLOON_MEMORY_HOTPLUG_LIMIT
102 #define P2M_LIMIT CONFIG_XEN_BALLOON_MEMORY_HOTPLUG_LIMIT
107 static DEFINE_SPINLOCK(p2m_update_lock);
109 static unsigned long *p2m_mid_missing_mfn;
110 static unsigned long *p2m_top_mfn;
111 static unsigned long **p2m_top_mfn_p;
112 static unsigned long *p2m_missing;
113 static unsigned long *p2m_identity;
114 static pte_t *p2m_missing_pte;
115 static pte_t *p2m_identity_pte;
118 * Hint at last populated PFN.
120 * Used to set HYPERVISOR_shared_info->arch.max_pfn so the toolstack
121 * can avoid scanning the whole P2M (which may be sized to account for
122 * hotplugged memory).
124 static unsigned long xen_p2m_last_pfn;
126 static inline unsigned p2m_top_index(unsigned long pfn)
128 BUG_ON(pfn >= MAX_P2M_PFN);
129 return pfn / (P2M_MID_PER_PAGE * P2M_PER_PAGE);
132 static inline unsigned p2m_mid_index(unsigned long pfn)
134 return (pfn / P2M_PER_PAGE) % P2M_MID_PER_PAGE;
137 static inline unsigned p2m_index(unsigned long pfn)
139 return pfn % P2M_PER_PAGE;
142 static void p2m_top_mfn_init(unsigned long *top)
146 for (i = 0; i < P2M_TOP_PER_PAGE; i++)
147 top[i] = virt_to_mfn(p2m_mid_missing_mfn);
150 static void p2m_top_mfn_p_init(unsigned long **top)
154 for (i = 0; i < P2M_TOP_PER_PAGE; i++)
155 top[i] = p2m_mid_missing_mfn;
158 static void p2m_mid_mfn_init(unsigned long *mid, unsigned long *leaf)
162 for (i = 0; i < P2M_MID_PER_PAGE; i++)
163 mid[i] = virt_to_mfn(leaf);
166 static void p2m_init(unsigned long *p2m)
170 for (i = 0; i < P2M_PER_PAGE; i++)
171 p2m[i] = INVALID_P2M_ENTRY;
174 static void p2m_init_identity(unsigned long *p2m, unsigned long pfn)
178 for (i = 0; i < P2M_PER_PAGE; i++)
179 p2m[i] = IDENTITY_FRAME(pfn + i);
182 static void * __ref alloc_p2m_page(void)
184 if (unlikely(!slab_is_available())) {
185 void *ptr = memblock_alloc(PAGE_SIZE, PAGE_SIZE);
188 panic("%s: Failed to allocate %lu bytes align=0x%lx\n",
189 __func__, PAGE_SIZE, PAGE_SIZE);
194 return (void *)__get_free_page(GFP_KERNEL);
197 static void __ref free_p2m_page(void *p)
199 if (unlikely(!slab_is_available())) {
200 memblock_free((unsigned long)p, PAGE_SIZE);
204 free_page((unsigned long)p);
208 * Build the parallel p2m_top_mfn and p2m_mid_mfn structures
210 * This is called both at boot time, and after resuming from suspend:
211 * - At boot time we're called rather early, and must use alloc_bootmem*()
212 * to allocate memory.
214 * - After resume we're called from within stop_machine, but the mfn
215 * tree should already be completely allocated.
217 void __ref xen_build_mfn_list_list(void)
219 unsigned long pfn, mfn;
221 unsigned int level, topidx, mididx;
222 unsigned long *mid_mfn_p;
224 if (xen_start_info->flags & SIF_VIRT_P2M_4TOOLS)
227 /* Pre-initialize p2m_top_mfn to be completely missing */
228 if (p2m_top_mfn == NULL) {
229 p2m_mid_missing_mfn = alloc_p2m_page();
230 p2m_mid_mfn_init(p2m_mid_missing_mfn, p2m_missing);
232 p2m_top_mfn_p = alloc_p2m_page();
233 p2m_top_mfn_p_init(p2m_top_mfn_p);
235 p2m_top_mfn = alloc_p2m_page();
236 p2m_top_mfn_init(p2m_top_mfn);
238 /* Reinitialise, mfn's all change after migration */
239 p2m_mid_mfn_init(p2m_mid_missing_mfn, p2m_missing);
242 for (pfn = 0; pfn < xen_max_p2m_pfn && pfn < MAX_P2M_PFN;
243 pfn += P2M_PER_PAGE) {
244 topidx = p2m_top_index(pfn);
245 mididx = p2m_mid_index(pfn);
247 mid_mfn_p = p2m_top_mfn_p[topidx];
248 ptep = lookup_address((unsigned long)(xen_p2m_addr + pfn),
250 BUG_ON(!ptep || level != PG_LEVEL_4K);
251 mfn = pte_mfn(*ptep);
252 ptep = (pte_t *)((unsigned long)ptep & ~(PAGE_SIZE - 1));
254 /* Don't bother allocating any mfn mid levels if
255 * they're just missing, just update the stored mfn,
256 * since all could have changed over a migrate.
258 if (ptep == p2m_missing_pte || ptep == p2m_identity_pte) {
260 BUG_ON(mid_mfn_p != p2m_mid_missing_mfn);
261 p2m_top_mfn[topidx] = virt_to_mfn(p2m_mid_missing_mfn);
262 pfn += (P2M_MID_PER_PAGE - 1) * P2M_PER_PAGE;
266 if (mid_mfn_p == p2m_mid_missing_mfn) {
267 mid_mfn_p = alloc_p2m_page();
268 p2m_mid_mfn_init(mid_mfn_p, p2m_missing);
270 p2m_top_mfn_p[topidx] = mid_mfn_p;
273 p2m_top_mfn[topidx] = virt_to_mfn(mid_mfn_p);
274 mid_mfn_p[mididx] = mfn;
278 void xen_setup_mfn_list_list(void)
280 BUG_ON(HYPERVISOR_shared_info == &xen_dummy_shared_info);
282 if (xen_start_info->flags & SIF_VIRT_P2M_4TOOLS)
283 HYPERVISOR_shared_info->arch.pfn_to_mfn_frame_list_list = ~0UL;
285 HYPERVISOR_shared_info->arch.pfn_to_mfn_frame_list_list =
286 virt_to_mfn(p2m_top_mfn);
287 HYPERVISOR_shared_info->arch.max_pfn = xen_p2m_last_pfn;
288 HYPERVISOR_shared_info->arch.p2m_generation = 0;
289 HYPERVISOR_shared_info->arch.p2m_vaddr = (unsigned long)xen_p2m_addr;
290 HYPERVISOR_shared_info->arch.p2m_cr3 =
291 xen_pfn_to_cr3(virt_to_mfn(swapper_pg_dir));
294 /* Set up p2m_top to point to the domain-builder provided p2m pages */
295 void __init xen_build_dynamic_phys_to_machine(void)
299 xen_p2m_addr = (unsigned long *)xen_start_info->mfn_list;
300 xen_p2m_size = ALIGN(xen_start_info->nr_pages, P2M_PER_PAGE);
302 for (pfn = xen_start_info->nr_pages; pfn < xen_p2m_size; pfn++)
303 xen_p2m_addr[pfn] = INVALID_P2M_ENTRY;
305 xen_max_p2m_pfn = xen_p2m_size;
308 #define P2M_TYPE_IDENTITY 0
309 #define P2M_TYPE_MISSING 1
310 #define P2M_TYPE_PFN 2
311 #define P2M_TYPE_UNKNOWN 3
313 static int xen_p2m_elem_type(unsigned long pfn)
317 if (pfn >= xen_p2m_size)
318 return P2M_TYPE_IDENTITY;
320 mfn = xen_p2m_addr[pfn];
322 if (mfn == INVALID_P2M_ENTRY)
323 return P2M_TYPE_MISSING;
325 if (mfn & IDENTITY_FRAME_BIT)
326 return P2M_TYPE_IDENTITY;
331 static void __init xen_rebuild_p2m_list(unsigned long *p2m)
333 unsigned int i, chunk;
340 p2m_missing = alloc_p2m_page();
341 p2m_init(p2m_missing);
342 p2m_identity = alloc_p2m_page();
343 p2m_init(p2m_identity);
345 p2m_missing_pte = alloc_p2m_page();
346 paravirt_alloc_pte(&init_mm, __pa(p2m_missing_pte) >> PAGE_SHIFT);
347 p2m_identity_pte = alloc_p2m_page();
348 paravirt_alloc_pte(&init_mm, __pa(p2m_identity_pte) >> PAGE_SHIFT);
349 for (i = 0; i < PTRS_PER_PTE; i++) {
350 set_pte(p2m_missing_pte + i,
351 pfn_pte(PFN_DOWN(__pa(p2m_missing)), PAGE_KERNEL_RO));
352 set_pte(p2m_identity_pte + i,
353 pfn_pte(PFN_DOWN(__pa(p2m_identity)), PAGE_KERNEL_RO));
356 for (pfn = 0; pfn < xen_max_p2m_pfn; pfn += chunk) {
358 * Try to map missing/identity PMDs or p2m-pages if possible.
359 * We have to respect the structure of the mfn_list_list
360 * which will be built just afterwards.
361 * Chunk size to test is one p2m page if we are in the middle
362 * of a mfn_list_list mid page and the complete mid page area
363 * if we are at index 0 of the mid page. Please note that a
364 * mid page might cover more than one PMD, e.g. on 32 bit PAE
367 chunk = (pfn & (P2M_PER_PAGE * P2M_MID_PER_PAGE - 1)) ?
368 P2M_PER_PAGE : P2M_PER_PAGE * P2M_MID_PER_PAGE;
370 type = xen_p2m_elem_type(pfn);
372 if (type != P2M_TYPE_PFN)
373 for (i = 1; i < chunk; i++)
374 if (xen_p2m_elem_type(pfn + i) != type)
377 /* Reset to minimal chunk size. */
378 chunk = P2M_PER_PAGE;
380 if (type == P2M_TYPE_PFN || i < chunk) {
381 /* Use initial p2m page contents. */
382 mfns = alloc_p2m_page();
383 copy_page(mfns, xen_p2m_addr + pfn);
384 ptep = populate_extra_pte((unsigned long)(p2m + pfn));
386 pfn_pte(PFN_DOWN(__pa(mfns)), PAGE_KERNEL));
390 if (chunk == P2M_PER_PAGE) {
391 /* Map complete missing or identity p2m-page. */
392 mfns = (type == P2M_TYPE_MISSING) ?
393 p2m_missing : p2m_identity;
394 ptep = populate_extra_pte((unsigned long)(p2m + pfn));
396 pfn_pte(PFN_DOWN(__pa(mfns)), PAGE_KERNEL_RO));
400 /* Complete missing or identity PMD(s) can be mapped. */
401 ptep = (type == P2M_TYPE_MISSING) ?
402 p2m_missing_pte : p2m_identity_pte;
403 for (i = 0; i < PMDS_PER_MID_PAGE; i++) {
404 pmdp = populate_extra_pmd(
405 (unsigned long)(p2m + pfn) + i * PMD_SIZE);
406 set_pmd(pmdp, __pmd(__pa(ptep) | _KERNPG_TABLE));
411 void __init xen_vmalloc_p2m_tree(void)
413 static struct vm_struct vm;
414 unsigned long p2m_limit;
416 xen_p2m_last_pfn = xen_max_p2m_pfn;
418 p2m_limit = (phys_addr_t)P2M_LIMIT * 1024 * 1024 * 1024 / PAGE_SIZE;
419 if (!p2m_limit && IS_ENABLED(CONFIG_XEN_UNPOPULATED_ALLOC))
420 p2m_limit = xen_start_info->nr_pages * XEN_EXTRA_MEM_RATIO;
423 vm.size = ALIGN(sizeof(unsigned long) * max(xen_max_p2m_pfn, p2m_limit),
424 PMD_SIZE * PMDS_PER_MID_PAGE);
425 vm_area_register_early(&vm, PMD_SIZE * PMDS_PER_MID_PAGE);
426 pr_notice("p2m virtual area at %p, size is %lx\n", vm.addr, vm.size);
428 xen_max_p2m_pfn = vm.size / sizeof(unsigned long);
430 xen_rebuild_p2m_list(vm.addr);
432 xen_p2m_addr = vm.addr;
433 xen_p2m_size = xen_max_p2m_pfn;
438 unsigned long get_phys_to_machine(unsigned long pfn)
443 if (unlikely(pfn >= xen_p2m_size)) {
444 if (pfn < xen_max_p2m_pfn)
445 return xen_chk_extra_mem(pfn);
447 return IDENTITY_FRAME(pfn);
450 ptep = lookup_address((unsigned long)(xen_p2m_addr + pfn), &level);
451 BUG_ON(!ptep || level != PG_LEVEL_4K);
454 * The INVALID_P2M_ENTRY is filled in both p2m_*identity
455 * and in p2m_*missing, so returning the INVALID_P2M_ENTRY
458 if (pte_pfn(*ptep) == PFN_DOWN(__pa(p2m_identity)))
459 return IDENTITY_FRAME(pfn);
461 return xen_p2m_addr[pfn];
463 EXPORT_SYMBOL_GPL(get_phys_to_machine);
466 * Allocate new pmd(s). It is checked whether the old pmd is still in place.
467 * If not, nothing is changed. This is okay as the only reason for allocating
468 * a new pmd is to replace p2m_missing_pte or p2m_identity_pte by a individual
471 static pte_t *alloc_p2m_pmd(unsigned long addr, pte_t *pte_pg)
474 pte_t *pte_newpg[PMDS_PER_MID_PAGE];
481 /* Do all allocations first to bail out in error case. */
482 for (i = 0; i < PMDS_PER_MID_PAGE; i++) {
483 pte_newpg[i] = alloc_p2m_page();
485 for (i--; i >= 0; i--)
486 free_p2m_page(pte_newpg[i]);
492 vaddr = addr & ~(PMD_SIZE * PMDS_PER_MID_PAGE - 1);
494 for (i = 0; i < PMDS_PER_MID_PAGE; i++) {
495 copy_page(pte_newpg[i], pte_pg);
496 paravirt_alloc_pte(&init_mm, __pa(pte_newpg[i]) >> PAGE_SHIFT);
498 pmdp = lookup_pmd_address(vaddr);
501 spin_lock_irqsave(&p2m_update_lock, flags);
503 ptechk = lookup_address(vaddr, &level);
504 if (ptechk == pte_pg) {
505 HYPERVISOR_shared_info->arch.p2m_generation++;
506 wmb(); /* Tools are synchronizing via p2m_generation. */
508 __pmd(__pa(pte_newpg[i]) | _KERNPG_TABLE));
509 wmb(); /* Tools are synchronizing via p2m_generation. */
510 HYPERVISOR_shared_info->arch.p2m_generation++;
514 spin_unlock_irqrestore(&p2m_update_lock, flags);
517 paravirt_release_pte(__pa(pte_newpg[i]) >> PAGE_SHIFT);
518 free_p2m_page(pte_newpg[i]);
524 return lookup_address(addr, &level);
528 * Fully allocate the p2m structure for a given pfn. We need to check
529 * that both the top and mid levels are allocated, and make sure the
530 * parallel mfn tree is kept in sync. We may race with other cpus, so
531 * the new pages are installed with cmpxchg; if we lose the race then
532 * simply free the page we allocated and use the one that's there.
534 int xen_alloc_p2m_entry(unsigned long pfn)
537 unsigned long *top_mfn_p, *mid_mfn;
538 pte_t *ptep, *pte_pg;
541 unsigned long addr = (unsigned long)(xen_p2m_addr + pfn);
542 unsigned long p2m_pfn;
544 ptep = lookup_address(addr, &level);
545 BUG_ON(!ptep || level != PG_LEVEL_4K);
546 pte_pg = (pte_t *)((unsigned long)ptep & ~(PAGE_SIZE - 1));
548 if (pte_pg == p2m_missing_pte || pte_pg == p2m_identity_pte) {
549 /* PMD level is missing, allocate a new one */
550 ptep = alloc_p2m_pmd(addr, pte_pg);
555 if (p2m_top_mfn && pfn < MAX_P2M_PFN) {
556 topidx = p2m_top_index(pfn);
557 top_mfn_p = &p2m_top_mfn[topidx];
558 mid_mfn = READ_ONCE(p2m_top_mfn_p[topidx]);
560 BUG_ON(virt_to_mfn(mid_mfn) != *top_mfn_p);
562 if (mid_mfn == p2m_mid_missing_mfn) {
563 /* Separately check the mid mfn level */
564 unsigned long missing_mfn;
565 unsigned long mid_mfn_mfn;
566 unsigned long old_mfn;
568 mid_mfn = alloc_p2m_page();
572 p2m_mid_mfn_init(mid_mfn, p2m_missing);
574 missing_mfn = virt_to_mfn(p2m_mid_missing_mfn);
575 mid_mfn_mfn = virt_to_mfn(mid_mfn);
576 old_mfn = cmpxchg(top_mfn_p, missing_mfn, mid_mfn_mfn);
577 if (old_mfn != missing_mfn) {
578 free_p2m_page(mid_mfn);
579 mid_mfn = mfn_to_virt(old_mfn);
581 p2m_top_mfn_p[topidx] = mid_mfn;
588 p2m_pfn = pte_pfn(READ_ONCE(*ptep));
589 if (p2m_pfn == PFN_DOWN(__pa(p2m_identity)) ||
590 p2m_pfn == PFN_DOWN(__pa(p2m_missing))) {
591 /* p2m leaf page is missing */
594 p2m = alloc_p2m_page();
598 if (p2m_pfn == PFN_DOWN(__pa(p2m_missing)))
601 p2m_init_identity(p2m, pfn & ~(P2M_PER_PAGE - 1));
603 spin_lock_irqsave(&p2m_update_lock, flags);
605 if (pte_pfn(*ptep) == p2m_pfn) {
606 HYPERVISOR_shared_info->arch.p2m_generation++;
607 wmb(); /* Tools are synchronizing via p2m_generation. */
609 pfn_pte(PFN_DOWN(__pa(p2m)), PAGE_KERNEL));
610 wmb(); /* Tools are synchronizing via p2m_generation. */
611 HYPERVISOR_shared_info->arch.p2m_generation++;
613 mid_mfn[p2m_mid_index(pfn)] = virt_to_mfn(p2m);
617 spin_unlock_irqrestore(&p2m_update_lock, flags);
623 /* Expanded the p2m? */
624 if (pfn > xen_p2m_last_pfn) {
625 xen_p2m_last_pfn = pfn;
626 HYPERVISOR_shared_info->arch.max_pfn = xen_p2m_last_pfn;
631 EXPORT_SYMBOL(xen_alloc_p2m_entry);
633 unsigned long __init set_phys_range_identity(unsigned long pfn_s,
638 if (unlikely(pfn_s >= xen_p2m_size))
644 if (pfn_e > xen_p2m_size)
645 pfn_e = xen_p2m_size;
647 for (pfn = pfn_s; pfn < pfn_e; pfn++)
648 xen_p2m_addr[pfn] = IDENTITY_FRAME(pfn);
653 bool __set_phys_to_machine(unsigned long pfn, unsigned long mfn)
658 /* Only invalid entries allowed above the highest p2m covered frame. */
659 if (unlikely(pfn >= xen_p2m_size))
660 return mfn == INVALID_P2M_ENTRY;
663 * The interface requires atomic updates on p2m elements.
664 * xen_safe_write_ulong() is using an atomic store via asm().
666 if (likely(!xen_safe_write_ulong(xen_p2m_addr + pfn, mfn)))
669 ptep = lookup_address((unsigned long)(xen_p2m_addr + pfn), &level);
670 BUG_ON(!ptep || level != PG_LEVEL_4K);
672 if (pte_pfn(*ptep) == PFN_DOWN(__pa(p2m_missing)))
673 return mfn == INVALID_P2M_ENTRY;
675 if (pte_pfn(*ptep) == PFN_DOWN(__pa(p2m_identity)))
676 return mfn == IDENTITY_FRAME(pfn);
681 bool set_phys_to_machine(unsigned long pfn, unsigned long mfn)
683 if (unlikely(!__set_phys_to_machine(pfn, mfn))) {
686 ret = xen_alloc_p2m_entry(pfn);
690 return __set_phys_to_machine(pfn, mfn);
696 int set_foreign_p2m_mapping(struct gnttab_map_grant_ref *map_ops,
697 struct gnttab_map_grant_ref *kmap_ops,
698 struct page **pages, unsigned int count)
703 if (xen_feature(XENFEAT_auto_translated_physmap))
707 ret = HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref,
713 for (i = 0; i < count; i++) {
714 unsigned long mfn, pfn;
715 struct gnttab_unmap_grant_ref unmap[2];
718 /* Do not add to override if the map failed. */
719 if (map_ops[i].status != GNTST_okay ||
720 (kmap_ops && kmap_ops[i].status != GNTST_okay))
723 if (map_ops[i].flags & GNTMAP_contains_pte) {
724 pte = (pte_t *)(mfn_to_virt(PFN_DOWN(map_ops[i].host_addr)) +
725 (map_ops[i].host_addr & ~PAGE_MASK));
728 mfn = PFN_DOWN(map_ops[i].dev_bus_addr);
730 pfn = page_to_pfn(pages[i]);
732 WARN(pfn_to_mfn(pfn) != INVALID_P2M_ENTRY, "page must be ballooned");
734 if (likely(set_phys_to_machine(pfn, FOREIGN_FRAME(mfn))))
738 * Signal an error for this slot. This in turn requires
739 * immediate unmapping.
741 map_ops[i].status = GNTST_general_error;
742 unmap[0].host_addr = map_ops[i].host_addr,
743 unmap[0].handle = map_ops[i].handle;
744 map_ops[i].handle = ~0;
745 if (map_ops[i].flags & GNTMAP_device_map)
746 unmap[0].dev_bus_addr = map_ops[i].dev_bus_addr;
748 unmap[0].dev_bus_addr = 0;
751 kmap_ops[i].status = GNTST_general_error;
752 unmap[1].host_addr = kmap_ops[i].host_addr,
753 unmap[1].handle = kmap_ops[i].handle;
754 kmap_ops[i].handle = ~0;
755 if (kmap_ops[i].flags & GNTMAP_device_map)
756 unmap[1].dev_bus_addr = kmap_ops[i].dev_bus_addr;
758 unmap[1].dev_bus_addr = 0;
762 * Pre-populate both status fields, to be recognizable in
763 * the log message below.
768 rc = HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref,
769 unmap, 1 + !!kmap_ops);
770 if (rc || unmap[0].status != GNTST_okay ||
771 unmap[1].status != GNTST_okay)
772 pr_err_once("gnttab unmap failed: rc=%d st0=%d st1=%d\n",
773 rc, unmap[0].status, unmap[1].status);
780 int clear_foreign_p2m_mapping(struct gnttab_unmap_grant_ref *unmap_ops,
781 struct gnttab_unmap_grant_ref *kunmap_ops,
782 struct page **pages, unsigned int count)
786 if (xen_feature(XENFEAT_auto_translated_physmap))
789 for (i = 0; i < count; i++) {
790 unsigned long mfn = __pfn_to_mfn(page_to_pfn(pages[i]));
791 unsigned long pfn = page_to_pfn(pages[i]);
793 if (mfn != INVALID_P2M_ENTRY && (mfn & FOREIGN_FRAME_BIT))
794 set_phys_to_machine(pfn, INVALID_P2M_ENTRY);
799 ret = HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref,
800 kunmap_ops, count) ?: ret;
805 #ifdef CONFIG_XEN_DEBUG_FS
806 #include <linux/debugfs.h>
808 static int p2m_dump_show(struct seq_file *m, void *v)
810 static const char * const type_name[] = {
811 [P2M_TYPE_IDENTITY] = "identity",
812 [P2M_TYPE_MISSING] = "missing",
813 [P2M_TYPE_PFN] = "pfn",
814 [P2M_TYPE_UNKNOWN] = "abnormal"};
815 unsigned long pfn, first_pfn;
818 prev_type = xen_p2m_elem_type(0);
821 for (pfn = 0; pfn < xen_p2m_size; pfn++) {
822 type = xen_p2m_elem_type(pfn);
823 if (type != prev_type) {
824 seq_printf(m, " [0x%lx->0x%lx] %s\n", first_pfn, pfn,
825 type_name[prev_type]);
830 seq_printf(m, " [0x%lx->0x%lx] %s\n", first_pfn, pfn,
831 type_name[prev_type]);
835 DEFINE_SHOW_ATTRIBUTE(p2m_dump);
837 static struct dentry *d_mmu_debug;
839 static int __init xen_p2m_debugfs(void)
841 struct dentry *d_xen = xen_init_debugfs();
843 d_mmu_debug = debugfs_create_dir("mmu", d_xen);
845 debugfs_create_file("p2m", 0600, d_mmu_debug, NULL, &p2m_dump_fops);
848 fs_initcall(xen_p2m_debugfs);
849 #endif /* CONFIG_XEN_DEBUG_FS */