1 // SPDX-License-Identifier: GPL-2.0
2
3 /*
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.
7 *
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.
11 *
12 * Xen
13 * |
14 * p2m_top_mfn
15 * / \
16 * p2m_mid_mfn p2m_mid_mfn
17 * / /
18 * p2m p2m p2m ...
19 *
20 * The p2m_mid_mfn pages are mapped by p2m_top_mfn_p.
21 *
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
25 *
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.
29 *
30 * In short, these structures contain the Machine Frame Number (MFN) of the PFN.
31 *
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.
39 *
40 * We also have the possibility of setting 1-1 mappings on certain regions, so
41 * that:
42 * pfn_to_mfn(0xc0000)=0xc0000
43 *
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.
47 *
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).
51 *
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).
57 *
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.
62 */
63
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>
73 #include <linux/acpi.h>
74
75 #include <asm/cache.h>
76 #include <asm/setup.h>
77 #include <linux/uaccess.h>
78
79 #include <asm/xen/page.h>
80 #include <asm/xen/hypercall.h>
81 #include <asm/xen/hypervisor.h>
82 #include <xen/balloon.h>
83 #include <xen/grant_table.h>
84 #include <xen/hvc-console.h>
85
86 #include "xen-ops.h"
87
88 #define P2M_MID_PER_PAGE (PAGE_SIZE / sizeof(unsigned long *))
89 #define P2M_TOP_PER_PAGE (PAGE_SIZE / sizeof(unsigned long **))
90
91 #define MAX_P2M_PFN (P2M_TOP_PER_PAGE * P2M_MID_PER_PAGE * P2M_PER_PAGE)
92
93 #define PMDS_PER_MID_PAGE (P2M_MID_PER_PAGE / PTRS_PER_PTE)
94
95 unsigned long *xen_p2m_addr __read_mostly;
96 EXPORT_SYMBOL_GPL(xen_p2m_addr);
97 unsigned long xen_p2m_size __read_mostly;
98 EXPORT_SYMBOL_GPL(xen_p2m_size);
99 unsigned long xen_max_p2m_pfn __read_mostly;
100 EXPORT_SYMBOL_GPL(xen_max_p2m_pfn);
101
102 #ifdef CONFIG_XEN_MEMORY_HOTPLUG_LIMIT
103 #define P2M_LIMIT CONFIG_XEN_MEMORY_HOTPLUG_LIMIT
104 #else
105 #define P2M_LIMIT 0
106 #endif
107
108 static DEFINE_SPINLOCK(p2m_update_lock);
109
110 static unsigned long *p2m_mid_missing_mfn;
111 static unsigned long *p2m_top_mfn;
112 static unsigned long **p2m_top_mfn_p;
113 static unsigned long *p2m_missing;
114 static unsigned long *p2m_identity;
115 static pte_t *p2m_missing_pte;
116 static pte_t *p2m_identity_pte;
117
118 /*
119 * Hint at last populated PFN.
120 *
121 * Used to set HYPERVISOR_shared_info->arch.max_pfn so the toolstack
122 * can avoid scanning the whole P2M (which may be sized to account for
123 * hotplugged memory).
124 */
125 static unsigned long xen_p2m_last_pfn;
126
127 static inline unsigned p2m_top_index(unsigned long pfn)
128 {
129 BUG_ON(pfn >= MAX_P2M_PFN);
130 return pfn / (P2M_MID_PER_PAGE * P2M_PER_PAGE);
131 }
132
133 static inline unsigned p2m_mid_index(unsigned long pfn)
134 {
135 return (pfn / P2M_PER_PAGE) % P2M_MID_PER_PAGE;
136 }
137
138 static void p2m_top_mfn_init(unsigned long *top)
139 {
140 unsigned i;
141
142 for (i = 0; i < P2M_TOP_PER_PAGE; i++)
143 top[i] = virt_to_mfn(p2m_mid_missing_mfn);
144 }
145
146 static void p2m_top_mfn_p_init(unsigned long **top)
147 {
148 unsigned i;
149
150 for (i = 0; i < P2M_TOP_PER_PAGE; i++)
151 top[i] = p2m_mid_missing_mfn;
152 }
153
154 static void p2m_mid_mfn_init(unsigned long *mid, unsigned long *leaf)
155 {
156 unsigned i;
157
158 for (i = 0; i < P2M_MID_PER_PAGE; i++)
159 mid[i] = virt_to_mfn(leaf);
160 }
161
162 static void p2m_init(unsigned long *p2m)
163 {
164 unsigned i;
165
166 for (i = 0; i < P2M_PER_PAGE; i++)
167 p2m[i] = INVALID_P2M_ENTRY;
168 }
169
170 static void p2m_init_identity(unsigned long *p2m, unsigned long pfn)
171 {
172 unsigned i;
173
174 for (i = 0; i < P2M_PER_PAGE; i++)
175 p2m[i] = IDENTITY_FRAME(pfn + i);
176 }
177
178 static void * __ref alloc_p2m_page(void)
179 {
180 if (unlikely(!slab_is_available())) {
181 void *ptr = memblock_alloc(PAGE_SIZE, PAGE_SIZE);
182
183 if (!ptr)
184 panic("%s: Failed to allocate %lu bytes align=0x%lx\n",
185 __func__, PAGE_SIZE, PAGE_SIZE);
186
187 return ptr;
188 }
189
190 return (void *)__get_free_page(GFP_KERNEL);
191 }
192
193 static void __ref free_p2m_page(void *p)
194 {
195 if (unlikely(!slab_is_available())) {
196 memblock_free(p, PAGE_SIZE);
197 return;
198 }
199
200 free_page((unsigned long)p);
201 }
202
203 /*
204 * Build the parallel p2m_top_mfn and p2m_mid_mfn structures
205 *
206 * This is called both at boot time, and after resuming from suspend:
207 * - At boot time we're called rather early, and must use alloc_bootmem*()
208 * to allocate memory.
209 *
210 * - After resume we're called from within stop_machine, but the mfn
211 * tree should already be completely allocated.
212 */
213 void __ref xen_build_mfn_list_list(void)
214 {
215 unsigned long pfn, mfn;
216 pte_t *ptep;
217 unsigned int level, topidx, mididx;
218 unsigned long *mid_mfn_p;
219
220 if (xen_start_info->flags & SIF_VIRT_P2M_4TOOLS)
221 return;
222
223 /* Pre-initialize p2m_top_mfn to be completely missing */
224 if (p2m_top_mfn == NULL) {
225 p2m_mid_missing_mfn = alloc_p2m_page();
226 p2m_mid_mfn_init(p2m_mid_missing_mfn, p2m_missing);
227
228 p2m_top_mfn_p = alloc_p2m_page();
229 p2m_top_mfn_p_init(p2m_top_mfn_p);
230
231 p2m_top_mfn = alloc_p2m_page();
232 p2m_top_mfn_init(p2m_top_mfn);
233 } else {
234 /* Reinitialise, mfn's all change after migration */
235 p2m_mid_mfn_init(p2m_mid_missing_mfn, p2m_missing);
236 }
237
238 for (pfn = 0; pfn < xen_max_p2m_pfn && pfn < MAX_P2M_PFN;
239 pfn += P2M_PER_PAGE) {
240 topidx = p2m_top_index(pfn);
241 mididx = p2m_mid_index(pfn);
242
243 mid_mfn_p = p2m_top_mfn_p[topidx];
244 ptep = lookup_address((unsigned long)(xen_p2m_addr + pfn),
245 &level);
246 BUG_ON(!ptep || level != PG_LEVEL_4K);
247 mfn = pte_mfn(*ptep);
248 ptep = (pte_t *)((unsigned long)ptep & ~(PAGE_SIZE - 1));
249
250 /* Don't bother allocating any mfn mid levels if
251 * they're just missing, just update the stored mfn,
252 * since all could have changed over a migrate.
253 */
254 if (ptep == p2m_missing_pte || ptep == p2m_identity_pte) {
255 BUG_ON(mididx);
256 BUG_ON(mid_mfn_p != p2m_mid_missing_mfn);
257 p2m_top_mfn[topidx] = virt_to_mfn(p2m_mid_missing_mfn);
258 pfn += (P2M_MID_PER_PAGE - 1) * P2M_PER_PAGE;
259 continue;
260 }
261
262 if (mid_mfn_p == p2m_mid_missing_mfn) {
263 mid_mfn_p = alloc_p2m_page();
264 p2m_mid_mfn_init(mid_mfn_p, p2m_missing);
265
266 p2m_top_mfn_p[topidx] = mid_mfn_p;
267 }
268
269 p2m_top_mfn[topidx] = virt_to_mfn(mid_mfn_p);
270 mid_mfn_p[mididx] = mfn;
271 }
272 }
273
274 void xen_setup_mfn_list_list(void)
275 {
276 BUG_ON(HYPERVISOR_shared_info == &xen_dummy_shared_info);
277
278 if (xen_start_info->flags & SIF_VIRT_P2M_4TOOLS)
279 HYPERVISOR_shared_info->arch.pfn_to_mfn_frame_list_list = ~0UL;
280 else
281 HYPERVISOR_shared_info->arch.pfn_to_mfn_frame_list_list =
282 virt_to_mfn(p2m_top_mfn);
283 HYPERVISOR_shared_info->arch.max_pfn = xen_p2m_last_pfn;
284 HYPERVISOR_shared_info->arch.p2m_generation = 0;
285 HYPERVISOR_shared_info->arch.p2m_vaddr = (unsigned long)xen_p2m_addr;
286 HYPERVISOR_shared_info->arch.p2m_cr3 =
287 xen_pfn_to_cr3(virt_to_mfn(swapper_pg_dir));
288 }
289
290 /* Set up p2m_top to point to the domain-builder provided p2m pages */
291 void __init xen_build_dynamic_phys_to_machine(void)
292 {
293 unsigned long pfn;
294
295 xen_p2m_addr = (unsigned long *)xen_start_info->mfn_list;
296 xen_p2m_size = ALIGN(xen_start_info->nr_pages, P2M_PER_PAGE);
297
298 for (pfn = xen_start_info->nr_pages; pfn < xen_p2m_size; pfn++)
299 xen_p2m_addr[pfn] = INVALID_P2M_ENTRY;
300
301 xen_max_p2m_pfn = xen_p2m_size;
302 }
303
304 #define P2M_TYPE_IDENTITY 0
305 #define P2M_TYPE_MISSING 1
306 #define P2M_TYPE_PFN 2
307 #define P2M_TYPE_UNKNOWN 3
308
309 static int xen_p2m_elem_type(unsigned long pfn)
310 {
311 unsigned long mfn;
312
313 if (pfn >= xen_p2m_size)
314 return P2M_TYPE_IDENTITY;
315
316 mfn = xen_p2m_addr[pfn];
317
318 if (mfn == INVALID_P2M_ENTRY)
319 return P2M_TYPE_MISSING;
320
321 if (mfn & IDENTITY_FRAME_BIT)
322 return P2M_TYPE_IDENTITY;
323
324 return P2M_TYPE_PFN;
325 }
326
327 static void __init xen_rebuild_p2m_list(unsigned long *p2m)
328 {
329 unsigned int i, chunk;
330 unsigned long pfn;
331 unsigned long *mfns;
332 pte_t *ptep;
333 pmd_t *pmdp;
334 int type;
335
336 p2m_missing = alloc_p2m_page();
337 p2m_init(p2m_missing);
338 p2m_identity = alloc_p2m_page();
339 p2m_init(p2m_identity);
340
341 p2m_missing_pte = alloc_p2m_page();
342 paravirt_alloc_pte(&init_mm, __pa(p2m_missing_pte) >> PAGE_SHIFT);
343 p2m_identity_pte = alloc_p2m_page();
344 paravirt_alloc_pte(&init_mm, __pa(p2m_identity_pte) >> PAGE_SHIFT);
345 for (i = 0; i < PTRS_PER_PTE; i++) {
346 set_pte(p2m_missing_pte + i,
347 pfn_pte(PFN_DOWN(__pa(p2m_missing)), PAGE_KERNEL_RO));
348 set_pte(p2m_identity_pte + i,
349 pfn_pte(PFN_DOWN(__pa(p2m_identity)), PAGE_KERNEL_RO));
350 }
351
352 for (pfn = 0; pfn < xen_max_p2m_pfn; pfn += chunk) {
353 /*
354 * Try to map missing/identity PMDs or p2m-pages if possible.
355 * We have to respect the structure of the mfn_list_list
356 * which will be built just afterwards.
357 * Chunk size to test is one p2m page if we are in the middle
358 * of a mfn_list_list mid page and the complete mid page area
359 * if we are at index 0 of the mid page. Please note that a
360 * mid page might cover more than one PMD, e.g. on 32 bit PAE
361 * kernels.
362 */
363 chunk = (pfn & (P2M_PER_PAGE * P2M_MID_PER_PAGE - 1)) ?
364 P2M_PER_PAGE : P2M_PER_PAGE * P2M_MID_PER_PAGE;
365
366 type = xen_p2m_elem_type(pfn);
367 i = 0;
368 if (type != P2M_TYPE_PFN)
369 for (i = 1; i < chunk; i++)
370 if (xen_p2m_elem_type(pfn + i) != type)
371 break;
372 if (i < chunk)
373 /* Reset to minimal chunk size. */
374 chunk = P2M_PER_PAGE;
375
376 if (type == P2M_TYPE_PFN || i < chunk) {
377 /* Use initial p2m page contents. */
378 mfns = alloc_p2m_page();
379 copy_page(mfns, xen_p2m_addr + pfn);
380 ptep = populate_extra_pte((unsigned long)(p2m + pfn));
381 set_pte(ptep,
382 pfn_pte(PFN_DOWN(__pa(mfns)), PAGE_KERNEL));
383 continue;
384 }
385
386 if (chunk == P2M_PER_PAGE) {
387 /* Map complete missing or identity p2m-page. */
388 mfns = (type == P2M_TYPE_MISSING) ?
389 p2m_missing : p2m_identity;
390 ptep = populate_extra_pte((unsigned long)(p2m + pfn));
391 set_pte(ptep,
392 pfn_pte(PFN_DOWN(__pa(mfns)), PAGE_KERNEL_RO));
393 continue;
394 }
395
396 /* Complete missing or identity PMD(s) can be mapped. */
397 ptep = (type == P2M_TYPE_MISSING) ?
398 p2m_missing_pte : p2m_identity_pte;
399 for (i = 0; i < PMDS_PER_MID_PAGE; i++) {
400 pmdp = populate_extra_pmd(
401 (unsigned long)(p2m + pfn) + i * PMD_SIZE);
402 set_pmd(pmdp, __pmd(__pa(ptep) | _KERNPG_TABLE));
403 }
404 }
405 }
406
407 void __init xen_vmalloc_p2m_tree(void)
408 {
409 static struct vm_struct vm;
410 unsigned long p2m_limit;
411
412 xen_p2m_last_pfn = xen_max_p2m_pfn;
413
414 p2m_limit = (phys_addr_t)P2M_LIMIT * 1024 * 1024 * 1024 / PAGE_SIZE;
415 vm.flags = VM_ALLOC;
416 vm.size = ALIGN(sizeof(unsigned long) * max(xen_max_p2m_pfn, p2m_limit),
417 PMD_SIZE * PMDS_PER_MID_PAGE);
418 vm_area_register_early(&vm, PMD_SIZE * PMDS_PER_MID_PAGE);
419 pr_notice("p2m virtual area at %p, size is %lx\n", vm.addr, vm.size);
420
421 xen_max_p2m_pfn = vm.size / sizeof(unsigned long);
422
423 xen_rebuild_p2m_list(vm.addr);
424
425 xen_p2m_addr = vm.addr;
426 xen_p2m_size = xen_max_p2m_pfn;
427
428 xen_inv_extra_mem();
429 }
430
431 unsigned long get_phys_to_machine(unsigned long pfn)
432 {
433 pte_t *ptep;
434 unsigned int level;
435
436 if (unlikely(pfn >= xen_p2m_size)) {
437 if (pfn < xen_max_p2m_pfn)
438 return xen_chk_extra_mem(pfn);
439
440 return IDENTITY_FRAME(pfn);
441 }
442
443 ptep = lookup_address((unsigned long)(xen_p2m_addr + pfn), &level);
444 BUG_ON(!ptep || level != PG_LEVEL_4K);
445
446 /*
447 * The INVALID_P2M_ENTRY is filled in both p2m_*identity
448 * and in p2m_*missing, so returning the INVALID_P2M_ENTRY
449 * would be wrong.
450 */
451 if (pte_pfn(*ptep) == PFN_DOWN(__pa(p2m_identity)))
452 return IDENTITY_FRAME(pfn);
453
454 return xen_p2m_addr[pfn];
455 }
456 EXPORT_SYMBOL_GPL(get_phys_to_machine);
457
458 /*
459 * Allocate new pmd(s). It is checked whether the old pmd is still in place.
460 * If not, nothing is changed. This is okay as the only reason for allocating
461 * a new pmd is to replace p2m_missing_pte or p2m_identity_pte by a individual
462 * pmd.
463 */
464 static pte_t *alloc_p2m_pmd(unsigned long addr, pte_t *pte_pg)
465 {
466 pte_t *ptechk;
467 pte_t *pte_newpg[PMDS_PER_MID_PAGE];
468 pmd_t *pmdp;
469 unsigned int level;
470 unsigned long flags;
471 unsigned long vaddr;
472 int i;
473
474 /* Do all allocations first to bail out in error case. */
475 for (i = 0; i < PMDS_PER_MID_PAGE; i++) {
476 pte_newpg[i] = alloc_p2m_page();
477 if (!pte_newpg[i]) {
478 for (i--; i >= 0; i--)
479 free_p2m_page(pte_newpg[i]);
480
481 return NULL;
482 }
483 }
484
485 vaddr = addr & ~(PMD_SIZE * PMDS_PER_MID_PAGE - 1);
486
487 for (i = 0; i < PMDS_PER_MID_PAGE; i++) {
488 copy_page(pte_newpg[i], pte_pg);
489 paravirt_alloc_pte(&init_mm, __pa(pte_newpg[i]) >> PAGE_SHIFT);
490
491 pmdp = lookup_pmd_address(vaddr);
492 BUG_ON(!pmdp);
493
494 spin_lock_irqsave(&p2m_update_lock, flags);
495
496 ptechk = lookup_address(vaddr, &level);
497 if (ptechk == pte_pg) {
498 HYPERVISOR_shared_info->arch.p2m_generation++;
499 wmb(); /* Tools are synchronizing via p2m_generation. */
500 set_pmd(pmdp,
501 __pmd(__pa(pte_newpg[i]) | _KERNPG_TABLE));
502 wmb(); /* Tools are synchronizing via p2m_generation. */
503 HYPERVISOR_shared_info->arch.p2m_generation++;
504 pte_newpg[i] = NULL;
505 }
506
507 spin_unlock_irqrestore(&p2m_update_lock, flags);
508
509 if (pte_newpg[i]) {
510 paravirt_release_pte(__pa(pte_newpg[i]) >> PAGE_SHIFT);
511 free_p2m_page(pte_newpg[i]);
512 }
513
514 vaddr += PMD_SIZE;
515 }
516
517 return lookup_address(addr, &level);
518 }
519
520 /*
521 * Fully allocate the p2m structure for a given pfn. We need to check
522 * that both the top and mid levels are allocated, and make sure the
523 * parallel mfn tree is kept in sync. We may race with other cpus, so
524 * the new pages are installed with cmpxchg; if we lose the race then
525 * simply free the page we allocated and use the one that's there.
526 */
527 int xen_alloc_p2m_entry(unsigned long pfn)
528 {
529 unsigned topidx;
530 unsigned long *top_mfn_p, *mid_mfn;
531 pte_t *ptep, *pte_pg;
532 unsigned int level;
533 unsigned long flags;
534 unsigned long addr = (unsigned long)(xen_p2m_addr + pfn);
535 unsigned long p2m_pfn;
536
537 ptep = lookup_address(addr, &level);
538 BUG_ON(!ptep || level != PG_LEVEL_4K);
539 pte_pg = (pte_t *)((unsigned long)ptep & ~(PAGE_SIZE - 1));
540
541 if (pte_pg == p2m_missing_pte || pte_pg == p2m_identity_pte) {
542 /* PMD level is missing, allocate a new one */
543 ptep = alloc_p2m_pmd(addr, pte_pg);
544 if (!ptep)
545 return -ENOMEM;
546 }
547
548 if (p2m_top_mfn && pfn < MAX_P2M_PFN) {
549 topidx = p2m_top_index(pfn);
550 top_mfn_p = &p2m_top_mfn[topidx];
551 mid_mfn = READ_ONCE(p2m_top_mfn_p[topidx]);
552
553 BUG_ON(virt_to_mfn(mid_mfn) != *top_mfn_p);
554
555 if (mid_mfn == p2m_mid_missing_mfn) {
556 /* Separately check the mid mfn level */
557 unsigned long missing_mfn;
558 unsigned long mid_mfn_mfn;
559
560 mid_mfn = alloc_p2m_page();
561 if (!mid_mfn)
562 return -ENOMEM;
563
564 p2m_mid_mfn_init(mid_mfn, p2m_missing);
565
566 missing_mfn = virt_to_mfn(p2m_mid_missing_mfn);
567 mid_mfn_mfn = virt_to_mfn(mid_mfn);
568 /* try_cmpxchg() updates missing_mfn on failure. */
569 if (try_cmpxchg(top_mfn_p, &missing_mfn, mid_mfn_mfn)) {
570 p2m_top_mfn_p[topidx] = mid_mfn;
571 } else {
572 free_p2m_page(mid_mfn);
573 mid_mfn = mfn_to_virt(missing_mfn);
574 }
575 }
576 } else {
577 mid_mfn = NULL;
578 }
579
580 p2m_pfn = pte_pfn(READ_ONCE(*ptep));
581 if (p2m_pfn == PFN_DOWN(__pa(p2m_identity)) ||
582 p2m_pfn == PFN_DOWN(__pa(p2m_missing))) {
583 /* p2m leaf page is missing */
584 unsigned long *p2m;
585
586 p2m = alloc_p2m_page();
587 if (!p2m)
588 return -ENOMEM;
589
590 if (p2m_pfn == PFN_DOWN(__pa(p2m_missing)))
591 p2m_init(p2m);
592 else
593 p2m_init_identity(p2m, pfn & ~(P2M_PER_PAGE - 1));
594
595 spin_lock_irqsave(&p2m_update_lock, flags);
596
597 if (pte_pfn(*ptep) == p2m_pfn) {
598 HYPERVISOR_shared_info->arch.p2m_generation++;
599 wmb(); /* Tools are synchronizing via p2m_generation. */
600 set_pte(ptep,
601 pfn_pte(PFN_DOWN(__pa(p2m)), PAGE_KERNEL));
602 wmb(); /* Tools are synchronizing via p2m_generation. */
603 HYPERVISOR_shared_info->arch.p2m_generation++;
604 if (mid_mfn)
605 mid_mfn[p2m_mid_index(pfn)] = virt_to_mfn(p2m);
606 p2m = NULL;
607 }
608
609 spin_unlock_irqrestore(&p2m_update_lock, flags);
610
611 if (p2m)
612 free_p2m_page(p2m);
613 }
614
615 /* Expanded the p2m? */
616 if (pfn >= xen_p2m_last_pfn) {
617 xen_p2m_last_pfn = ALIGN(pfn + 1, P2M_PER_PAGE);
618 HYPERVISOR_shared_info->arch.max_pfn = xen_p2m_last_pfn;
619 }
620
621 return 0;
622 }
623 EXPORT_SYMBOL(xen_alloc_p2m_entry);
624
625 unsigned long __init set_phys_range_identity(unsigned long pfn_s,
626 unsigned long pfn_e)
627 {
628 unsigned long pfn;
629
630 if (unlikely(pfn_s >= xen_p2m_size))
631 return 0;
632
633 if (pfn_s > pfn_e)
634 return 0;
635
636 if (pfn_e > xen_p2m_size)
637 pfn_e = xen_p2m_size;
638
639 for (pfn = pfn_s; pfn < pfn_e; pfn++)
640 xen_p2m_addr[pfn] = IDENTITY_FRAME(pfn);
641
642 return pfn - pfn_s;
643 }
644
645 bool __set_phys_to_machine(unsigned long pfn, unsigned long mfn)
646 {
647 pte_t *ptep;
648 unsigned int level;
649
650 /* Only invalid entries allowed above the highest p2m covered frame. */
651 if (unlikely(pfn >= xen_p2m_size))
652 return mfn == INVALID_P2M_ENTRY;
653
654 /*
655 * The interface requires atomic updates on p2m elements.
656 * xen_safe_write_ulong() is using an atomic store via asm().
657 */
658 if (likely(!xen_safe_write_ulong(xen_p2m_addr + pfn, mfn)))
659 return true;
660
661 ptep = lookup_address((unsigned long)(xen_p2m_addr + pfn), &level);
662 BUG_ON(!ptep || level != PG_LEVEL_4K);
663
664 if (pte_pfn(*ptep) == PFN_DOWN(__pa(p2m_missing)))
665 return mfn == INVALID_P2M_ENTRY;
666
667 if (pte_pfn(*ptep) == PFN_DOWN(__pa(p2m_identity)))
668 return mfn == IDENTITY_FRAME(pfn);
669
670 return false;
671 }
672
673 bool set_phys_to_machine(unsigned long pfn, unsigned long mfn)
674 {
675 if (unlikely(!__set_phys_to_machine(pfn, mfn))) {
676 int ret;
677
678 ret = xen_alloc_p2m_entry(pfn);
679 if (ret < 0)
680 return false;
681
682 return __set_phys_to_machine(pfn, mfn);
683 }
684
685 return true;
686 }
687
688 int set_foreign_p2m_mapping(struct gnttab_map_grant_ref *map_ops,
689 struct gnttab_map_grant_ref *kmap_ops,
690 struct page **pages, unsigned int count)
691 {
692 int i, ret = 0;
693 pte_t *pte;
694
695 if (xen_feature(XENFEAT_auto_translated_physmap))
696 return 0;
697
698 if (kmap_ops) {
699 ret = HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref,
700 kmap_ops, count);
701 if (ret)
702 goto out;
703 }
704
705 for (i = 0; i < count; i++) {
706 unsigned long mfn, pfn;
707 struct gnttab_unmap_grant_ref unmap[2];
708 int rc;
709
710 /* Do not add to override if the map failed. */
711 if (map_ops[i].status != GNTST_okay ||
712 (kmap_ops && kmap_ops[i].status != GNTST_okay))
713 continue;
714
715 if (map_ops[i].flags & GNTMAP_contains_pte) {
716 pte = (pte_t *)(mfn_to_virt(PFN_DOWN(map_ops[i].host_addr)) +
717 (map_ops[i].host_addr & ~PAGE_MASK));
718 mfn = pte_mfn(*pte);
719 } else {
720 mfn = PFN_DOWN(map_ops[i].dev_bus_addr);
721 }
722 pfn = page_to_pfn(pages[i]);
723
724 WARN(pfn_to_mfn(pfn) != INVALID_P2M_ENTRY, "page must be ballooned");
725
726 if (likely(set_phys_to_machine(pfn, FOREIGN_FRAME(mfn))))
727 continue;
728
729 /*
730 * Signal an error for this slot. This in turn requires
731 * immediate unmapping.
732 */
733 map_ops[i].status = GNTST_general_error;
734 unmap[0].host_addr = map_ops[i].host_addr;
735 unmap[0].handle = map_ops[i].handle;
736 map_ops[i].handle = INVALID_GRANT_HANDLE;
737 if (map_ops[i].flags & GNTMAP_device_map)
738 unmap[0].dev_bus_addr = map_ops[i].dev_bus_addr;
739 else
740 unmap[0].dev_bus_addr = 0;
741
742 if (kmap_ops) {
743 kmap_ops[i].status = GNTST_general_error;
744 unmap[1].host_addr = kmap_ops[i].host_addr;
745 unmap[1].handle = kmap_ops[i].handle;
746 kmap_ops[i].handle = INVALID_GRANT_HANDLE;
747 if (kmap_ops[i].flags & GNTMAP_device_map)
748 unmap[1].dev_bus_addr = kmap_ops[i].dev_bus_addr;
749 else
750 unmap[1].dev_bus_addr = 0;
751 }
752
753 /*
754 * Pre-populate both status fields, to be recognizable in
755 * the log message below.
756 */
757 unmap[0].status = 1;
758 unmap[1].status = 1;
759
760 rc = HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref,
761 unmap, 1 + !!kmap_ops);
762 if (rc || unmap[0].status != GNTST_okay ||
763 unmap[1].status != GNTST_okay)
764 pr_err_once("gnttab unmap failed: rc=%d st0=%d st1=%d\n",
765 rc, unmap[0].status, unmap[1].status);
766 }
767
768 out:
769 return ret;
770 }
771
772 int clear_foreign_p2m_mapping(struct gnttab_unmap_grant_ref *unmap_ops,
773 struct gnttab_unmap_grant_ref *kunmap_ops,
774 struct page **pages, unsigned int count)
775 {
776 int i, ret = 0;
777
778 if (xen_feature(XENFEAT_auto_translated_physmap))
779 return 0;
780
781 for (i = 0; i < count; i++) {
782 unsigned long mfn = __pfn_to_mfn(page_to_pfn(pages[i]));
783 unsigned long pfn = page_to_pfn(pages[i]);
784
785 if (mfn != INVALID_P2M_ENTRY && (mfn & FOREIGN_FRAME_BIT))
786 set_phys_to_machine(pfn, INVALID_P2M_ENTRY);
787 else
788 ret = -EINVAL;
789 }
790 if (kunmap_ops)
791 ret = HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref,
792 kunmap_ops, count) ?: ret;
793
794 return ret;
795 }
796
797 /* Remapped non-RAM areas */
798 #define NR_NONRAM_REMAP 4
799 static struct nonram_remap {
800 phys_addr_t maddr;
801 phys_addr_t paddr;
802 size_t size;
803 } xen_nonram_remap[NR_NONRAM_REMAP] __ro_after_init;
804 static unsigned int nr_nonram_remap __ro_after_init;
805
806 /*
807 * Do the real remapping of non-RAM regions as specified in the
808 * xen_nonram_remap[] array.
809 * In case of an error just crash the system.
810 */
811 void __init xen_do_remap_nonram(void)
812 {
813 unsigned int i;
814 unsigned int remapped = 0;
815 const struct nonram_remap *remap = xen_nonram_remap;
816 unsigned long pfn, mfn, end_pfn;
817
818 for (i = 0; i < nr_nonram_remap; i++) {
819 end_pfn = PFN_UP(remap->paddr + remap->size);
820 pfn = PFN_DOWN(remap->paddr);
821 mfn = PFN_DOWN(remap->maddr);
822 while (pfn < end_pfn) {
823 if (!set_phys_to_machine(pfn, mfn))
824 panic("Failed to set p2m mapping for pfn=%lx mfn=%lx\n",
825 pfn, mfn);
826
827 pfn++;
828 mfn++;
829 remapped++;
830 }
831
832 remap++;
833 }
834
835 pr_info("Remapped %u non-RAM page(s)\n", remapped);
836 }
837
838 #ifdef CONFIG_ACPI
839 /*
840 * Xen variant of acpi_os_ioremap() taking potentially remapped non-RAM
841 * regions into account.
842 * Any attempt to map an area crossing a remap boundary will produce a
843 * WARN() splat.
844 * phys is related to remap->maddr on input and will be rebased to remap->paddr.
845 */
846 static void __iomem *xen_acpi_os_ioremap(acpi_physical_address phys,
847 acpi_size size)
848 {
849 unsigned int i;
850 const struct nonram_remap *remap = xen_nonram_remap;
851
852 for (i = 0; i < nr_nonram_remap; i++) {
853 if (phys + size > remap->maddr &&
854 phys < remap->maddr + remap->size) {
855 WARN_ON(phys < remap->maddr ||
856 phys + size > remap->maddr + remap->size);
857 phys += remap->paddr - remap->maddr;
858 break;
859 }
860 }
861
862 return x86_acpi_os_ioremap(phys, size);
863 }
864 #endif /* CONFIG_ACPI */
865
866 /*
867 * Add a new non-RAM remap entry.
868 * In case of no free entry found, just crash the system.
869 */
870 void __init xen_add_remap_nonram(phys_addr_t maddr, phys_addr_t paddr,
871 unsigned long size)
872 {
873 BUG_ON((maddr & ~PAGE_MASK) != (paddr & ~PAGE_MASK));
874
875 if (nr_nonram_remap == NR_NONRAM_REMAP) {
876 xen_raw_console_write("Number of required E820 entry remapping actions exceed maximum value\n");
877 BUG();
878 }
879
880 #ifdef CONFIG_ACPI
881 /* Switch to the Xen acpi_os_ioremap() variant. */
882 if (nr_nonram_remap == 0)
883 acpi_os_ioremap = xen_acpi_os_ioremap;
884 #endif
885
886 xen_nonram_remap[nr_nonram_remap].maddr = maddr;
887 xen_nonram_remap[nr_nonram_remap].paddr = paddr;
888 xen_nonram_remap[nr_nonram_remap].size = size;
889
890 nr_nonram_remap++;
891 }
892
893 #ifdef CONFIG_XEN_DEBUG_FS
894 #include <linux/debugfs.h>
895 static int p2m_dump_show(struct seq_file *m, void *v)
896 {
897 static const char * const type_name[] = {
898 [P2M_TYPE_IDENTITY] = "identity",
899 [P2M_TYPE_MISSING] = "missing",
900 [P2M_TYPE_PFN] = "pfn",
901 [P2M_TYPE_UNKNOWN] = "abnormal"};
902 unsigned long pfn, first_pfn;
903 int type, prev_type;
904
905 prev_type = xen_p2m_elem_type(0);
906 first_pfn = 0;
907
908 for (pfn = 0; pfn < xen_p2m_size; pfn++) {
909 type = xen_p2m_elem_type(pfn);
910 if (type != prev_type) {
911 seq_printf(m, " [0x%lx->0x%lx] %s\n", first_pfn, pfn,
912 type_name[prev_type]);
913 prev_type = type;
914 first_pfn = pfn;
915 }
916 }
917 seq_printf(m, " [0x%lx->0x%lx] %s\n", first_pfn, pfn,
918 type_name[prev_type]);
919 return 0;
920 }
921
922 DEFINE_SHOW_ATTRIBUTE(p2m_dump);
923
924 static struct dentry *d_mmu_debug;
925
926 static int __init xen_p2m_debugfs(void)
927 {
928 struct dentry *d_xen = xen_init_debugfs();
929
930 d_mmu_debug = debugfs_create_dir("mmu", d_xen);
931
932 debugfs_create_file("p2m", 0600, d_mmu_debug, NULL, &p2m_dump_fops);
933 return 0;
934 }
935 fs_initcall(xen_p2m_debugfs);
936 #endif /* CONFIG_XEN_DEBUG_FS */
937
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