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 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); 93 94 static DEFINE_SPINLOCK(p2m_update_lock); 95 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; 103 104 static inline unsigned p2m_top_index(unsigned long pfn) 105 { 106 BUG_ON(pfn >= MAX_P2M_PFN); 107 return pfn / (P2M_MID_PER_PAGE * P2M_PER_PAGE); 108 } 109 110 static inline unsigned p2m_mid_index(unsigned long pfn) 111 { 112 return (pfn / P2M_PER_PAGE) % P2M_MID_PER_PAGE; 113 } 114 115 static inline unsigned p2m_index(unsigned long pfn) 116 { 117 return pfn % P2M_PER_PAGE; 118 } 119 120 static void p2m_top_mfn_init(unsigned long *top) 121 { 122 unsigned i; 123 124 for (i = 0; i < P2M_TOP_PER_PAGE; i++) 125 top[i] = virt_to_mfn(p2m_mid_missing_mfn); 126 } 127 128 static void p2m_top_mfn_p_init(unsigned long **top) 129 { 130 unsigned i; 131 132 for (i = 0; i < P2M_TOP_PER_PAGE; i++) 133 top[i] = p2m_mid_missing_mfn; 134 } 135 136 static void p2m_mid_mfn_init(unsigned long *mid, unsigned long *leaf) 137 { 138 unsigned i; 139 140 for (i = 0; i < P2M_MID_PER_PAGE; i++) 141 mid[i] = virt_to_mfn(leaf); 142 } 143 144 static void p2m_init(unsigned long *p2m) 145 { 146 unsigned i; 147 148 for (i = 0; i < P2M_PER_PAGE; i++) 149 p2m[i] = INVALID_P2M_ENTRY; 150 } 151 152 static void p2m_init_identity(unsigned long *p2m, unsigned long pfn) 153 { 154 unsigned i; 155 156 for (i = 0; i < P2M_PER_PAGE; i++) 157 p2m[i] = IDENTITY_FRAME(pfn + i); 158 } 159 160 static void * __ref alloc_p2m_page(void) 161 { 162 if (unlikely(!slab_is_available())) 163 return alloc_bootmem_align(PAGE_SIZE, PAGE_SIZE); 164 165 return (void *)__get_free_page(GFP_KERNEL | __GFP_REPEAT); 166 } 167 168 static void __ref free_p2m_page(void *p) 169 { 170 if (unlikely(!slab_is_available())) { 171 free_bootmem((unsigned long)p, PAGE_SIZE); 172 return; 173 } 174 175 free_page((unsigned long)p); 176 } 177 178 /* 179 * Build the parallel p2m_top_mfn and p2m_mid_mfn structures 180 * 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. 184 * 185 * - After resume we're called from within stop_machine, but the mfn 186 * tree should already be completely allocated. 187 */ 188 void __ref xen_build_mfn_list_list(void) 189 { 190 unsigned long pfn, mfn; 191 pte_t *ptep; 192 unsigned int level, topidx, mididx; 193 unsigned long *mid_mfn_p; 194 195 if (xen_feature(XENFEAT_auto_translated_physmap)) 196 return; 197 198 /* 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); 202 203 p2m_top_mfn_p = alloc_p2m_page(); 204 p2m_top_mfn_p_init(p2m_top_mfn_p); 205 206 p2m_top_mfn = alloc_p2m_page(); 207 p2m_top_mfn_init(p2m_top_mfn); 208 } else { 209 /* Reinitialise, mfn's all change after migration */ 210 p2m_mid_mfn_init(p2m_mid_missing_mfn, p2m_missing); 211 } 212 213 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); 217 218 mid_mfn_p = p2m_top_mfn_p[topidx]; 219 ptep = lookup_address((unsigned long)(xen_p2m_addr + pfn), 220 &level); 221 BUG_ON(!ptep || level != PG_LEVEL_4K); 222 mfn = pte_mfn(*ptep); 223 ptep = (pte_t *)((unsigned long)ptep & ~(PAGE_SIZE - 1)); 224 225 /* 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. 228 */ 229 if (ptep == p2m_missing_pte || ptep == p2m_identity_pte) { 230 BUG_ON(mididx); 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; 234 continue; 235 } 236 237 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); 240 241 p2m_top_mfn_p[topidx] = mid_mfn_p; 242 } 243 244 p2m_top_mfn[topidx] = virt_to_mfn(mid_mfn_p); 245 mid_mfn_p[mididx] = mfn; 246 } 247 } 248 249 void xen_setup_mfn_list_list(void) 250 { 251 if (xen_feature(XENFEAT_auto_translated_physmap)) 252 return; 253 254 BUG_ON(HYPERVISOR_shared_info == &xen_dummy_shared_info); 255 256 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; 259 } 260 261 /* Set up p2m_top to point to the domain-builder provided p2m pages */ 262 void __init xen_build_dynamic_phys_to_machine(void) 263 { 264 unsigned long pfn; 265 266 if (xen_feature(XENFEAT_auto_translated_physmap)) 267 return; 268 269 xen_p2m_addr = (unsigned long *)xen_start_info->mfn_list; 270 xen_p2m_size = ALIGN(xen_start_info->nr_pages, P2M_PER_PAGE); 271 272 for (pfn = xen_start_info->nr_pages; pfn < xen_p2m_size; pfn++) 273 xen_p2m_addr[pfn] = INVALID_P2M_ENTRY; 274 275 xen_max_p2m_pfn = xen_p2m_size; 276 } 277 278 #define P2M_TYPE_IDENTITY 0 279 #define P2M_TYPE_MISSING 1 280 #define P2M_TYPE_PFN 2 281 #define P2M_TYPE_UNKNOWN 3 282 283 static int xen_p2m_elem_type(unsigned long pfn) 284 { 285 unsigned long mfn; 286 287 if (pfn >= xen_p2m_size) 288 return P2M_TYPE_IDENTITY; 289 290 mfn = xen_p2m_addr[pfn]; 291 292 if (mfn == INVALID_P2M_ENTRY) 293 return P2M_TYPE_MISSING; 294 295 if (mfn & IDENTITY_FRAME_BIT) 296 return P2M_TYPE_IDENTITY; 297 298 return P2M_TYPE_PFN; 299 } 300 301 static void __init xen_rebuild_p2m_list(unsigned long *p2m) 302 { 303 unsigned int i, chunk; 304 unsigned long pfn; 305 unsigned long *mfns; 306 pte_t *ptep; 307 pmd_t *pmdp; 308 int type; 309 310 p2m_missing = alloc_p2m_page(); 311 p2m_init(p2m_missing); 312 p2m_identity = alloc_p2m_page(); 313 p2m_init(p2m_identity); 314 315 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)); 324 } 325 326 for (pfn = 0; pfn < xen_max_p2m_pfn; pfn += chunk) { 327 /* 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 335 * kernels. 336 */ 337 chunk = (pfn & (P2M_PER_PAGE * P2M_MID_PER_PAGE - 1)) ? 338 P2M_PER_PAGE : P2M_PER_PAGE * P2M_MID_PER_PAGE; 339 340 type = xen_p2m_elem_type(pfn); 341 i = 0; 342 if (type != P2M_TYPE_PFN) 343 for (i = 1; i < chunk; i++) 344 if (xen_p2m_elem_type(pfn + i) != type) 345 break; 346 if (i < chunk) 347 /* Reset to minimal chunk size. */ 348 chunk = P2M_PER_PAGE; 349 350 if (type == P2M_TYPE_PFN || i < chunk) { 351 /* Use initial p2m page contents. */ 352 #ifdef CONFIG_X86_64 353 mfns = alloc_p2m_page(); 354 copy_page(mfns, xen_p2m_addr + pfn); 355 #else 356 mfns = xen_p2m_addr + pfn; 357 #endif 358 ptep = populate_extra_pte((unsigned long)(p2m + pfn)); 359 set_pte(ptep, 360 pfn_pte(PFN_DOWN(__pa(mfns)), PAGE_KERNEL)); 361 continue; 362 } 363 364 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)); 369 set_pte(ptep, 370 pfn_pte(PFN_DOWN(__pa(mfns)), PAGE_KERNEL_RO)); 371 continue; 372 } 373 374 /* 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)); 381 } 382 } 383 } 384 385 void __init xen_vmalloc_p2m_tree(void) 386 { 387 static struct vm_struct vm; 388 389 vm.flags = VM_ALLOC; 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); 394 395 xen_max_p2m_pfn = vm.size / sizeof(unsigned long); 396 397 xen_rebuild_p2m_list(vm.addr); 398 399 xen_p2m_addr = vm.addr; 400 xen_p2m_size = xen_max_p2m_pfn; 401 402 xen_inv_extra_mem(); 403 } 404 405 unsigned long get_phys_to_machine(unsigned long pfn) 406 { 407 pte_t *ptep; 408 unsigned int level; 409 410 if (unlikely(pfn >= xen_p2m_size)) { 411 if (pfn < xen_max_p2m_pfn) 412 return xen_chk_extra_mem(pfn); 413 414 return IDENTITY_FRAME(pfn); 415 } 416 417 ptep = lookup_address((unsigned long)(xen_p2m_addr + pfn), &level); 418 BUG_ON(!ptep || level != PG_LEVEL_4K); 419 420 /* 421 * The INVALID_P2M_ENTRY is filled in both p2m_*identity 422 * and in p2m_*missing, so returning the INVALID_P2M_ENTRY 423 * would be wrong. 424 */ 425 if (pte_pfn(*ptep) == PFN_DOWN(__pa(p2m_identity))) 426 return IDENTITY_FRAME(pfn); 427 428 return xen_p2m_addr[pfn]; 429 } 430 EXPORT_SYMBOL_GPL(get_phys_to_machine); 431 432 /* 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! 437 */ 438 static pte_t *alloc_p2m_pmd(unsigned long addr, pte_t *pte_pg) 439 { 440 pte_t *ptechk; 441 pte_t *pte_newpg[PMDS_PER_MID_PAGE]; 442 pmd_t *pmdp; 443 unsigned int level; 444 unsigned long flags; 445 unsigned long vaddr; 446 int i; 447 448 /* 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(); 451 if (!pte_newpg[i]) { 452 for (i--; i >= 0; i--) 453 free_p2m_page(pte_newpg[i]); 454 455 return NULL; 456 } 457 } 458 459 vaddr = addr & ~(PMD_SIZE * PMDS_PER_MID_PAGE - 1); 460 461 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); 464 465 pmdp = lookup_pmd_address(vaddr); 466 BUG_ON(!pmdp); 467 468 spin_lock_irqsave(&p2m_update_lock, flags); 469 470 ptechk = lookup_address(vaddr, &level); 471 if (ptechk == pte_pg) { 472 set_pmd(pmdp, 473 __pmd(__pa(pte_newpg[i]) | _KERNPG_TABLE)); 474 pte_newpg[i] = NULL; 475 } 476 477 spin_unlock_irqrestore(&p2m_update_lock, flags); 478 479 if (pte_newpg[i]) { 480 paravirt_release_pte(__pa(pte_newpg[i]) >> PAGE_SHIFT); 481 free_p2m_page(pte_newpg[i]); 482 } 483 484 vaddr += PMD_SIZE; 485 } 486 487 return lookup_address(addr, &level); 488 } 489 490 /* 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. 496 */ 497 static bool alloc_p2m(unsigned long pfn) 498 { 499 unsigned topidx, mididx; 500 unsigned long *top_mfn_p, *mid_mfn; 501 pte_t *ptep, *pte_pg; 502 unsigned int level; 503 unsigned long flags; 504 unsigned long addr = (unsigned long)(xen_p2m_addr + pfn); 505 unsigned long p2m_pfn; 506 507 topidx = p2m_top_index(pfn); 508 mididx = p2m_mid_index(pfn); 509 510 ptep = lookup_address(addr, &level); 511 BUG_ON(!ptep || level != PG_LEVEL_4K); 512 pte_pg = (pte_t *)((unsigned long)ptep & ~(PAGE_SIZE - 1)); 513 514 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); 517 if (!ptep) 518 return false; 519 } 520 521 if (p2m_top_mfn) { 522 top_mfn_p = &p2m_top_mfn[topidx]; 523 mid_mfn = ACCESS_ONCE(p2m_top_mfn_p[topidx]); 524 525 BUG_ON(virt_to_mfn(mid_mfn) != *top_mfn_p); 526 527 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; 532 533 mid_mfn = alloc_p2m_page(); 534 if (!mid_mfn) 535 return false; 536 537 p2m_mid_mfn_init(mid_mfn, p2m_missing); 538 539 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); 545 } else { 546 p2m_top_mfn_p[topidx] = mid_mfn; 547 } 548 } 549 } else { 550 mid_mfn = NULL; 551 } 552 553 p2m_pfn = pte_pfn(READ_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 */ 557 unsigned long *p2m; 558 559 p2m = alloc_p2m_page(); 560 if (!p2m) 561 return false; 562 563 if (p2m_pfn == PFN_DOWN(__pa(p2m_missing))) 564 p2m_init(p2m); 565 else 566 p2m_init_identity(p2m, pfn & ~(P2M_PER_PAGE - 1)); 567 568 spin_lock_irqsave(&p2m_update_lock, flags); 569 570 if (pte_pfn(*ptep) == p2m_pfn) { 571 set_pte(ptep, 572 pfn_pte(PFN_DOWN(__pa(p2m)), PAGE_KERNEL)); 573 if (mid_mfn) 574 mid_mfn[mididx] = virt_to_mfn(p2m); 575 p2m = NULL; 576 } 577 578 spin_unlock_irqrestore(&p2m_update_lock, flags); 579 580 if (p2m) 581 free_p2m_page(p2m); 582 } 583 584 return true; 585 } 586 587 unsigned long __init set_phys_range_identity(unsigned long pfn_s, 588 unsigned long pfn_e) 589 { 590 unsigned long pfn; 591 592 if (unlikely(pfn_s >= xen_p2m_size)) 593 return 0; 594 595 if (unlikely(xen_feature(XENFEAT_auto_translated_physmap))) 596 return pfn_e - pfn_s; 597 598 if (pfn_s > pfn_e) 599 return 0; 600 601 if (pfn_e > xen_p2m_size) 602 pfn_e = xen_p2m_size; 603 604 for (pfn = pfn_s; pfn < pfn_e; pfn++) 605 xen_p2m_addr[pfn] = IDENTITY_FRAME(pfn); 606 607 return pfn - pfn_s; 608 } 609 610 bool __set_phys_to_machine(unsigned long pfn, unsigned long mfn) 611 { 612 pte_t *ptep; 613 unsigned int level; 614 615 /* don't track P2M changes in autotranslate guests */ 616 if (unlikely(xen_feature(XENFEAT_auto_translated_physmap))) 617 return true; 618 619 if (unlikely(pfn >= xen_p2m_size)) { 620 BUG_ON(mfn != INVALID_P2M_ENTRY); 621 return true; 622 } 623 624 if (likely(!xen_safe_write_ulong(xen_p2m_addr + pfn, mfn))) 625 return true; 626 627 ptep = lookup_address((unsigned long)(xen_p2m_addr + pfn), &level); 628 BUG_ON(!ptep || level != PG_LEVEL_4K); 629 630 if (pte_pfn(*ptep) == PFN_DOWN(__pa(p2m_missing))) 631 return mfn == INVALID_P2M_ENTRY; 632 633 if (pte_pfn(*ptep) == PFN_DOWN(__pa(p2m_identity))) 634 return mfn == IDENTITY_FRAME(pfn); 635 636 return false; 637 } 638 639 bool set_phys_to_machine(unsigned long pfn, unsigned long mfn) 640 { 641 if (unlikely(!__set_phys_to_machine(pfn, mfn))) { 642 if (!alloc_p2m(pfn)) 643 return false; 644 645 return __set_phys_to_machine(pfn, mfn); 646 } 647 648 return true; 649 } 650 651 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) 654 { 655 int i, ret = 0; 656 pte_t *pte; 657 658 if (xen_feature(XENFEAT_auto_translated_physmap)) 659 return 0; 660 661 if (kmap_ops) { 662 ret = HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, 663 kmap_ops, count); 664 if (ret) 665 goto out; 666 } 667 668 for (i = 0; i < count; i++) { 669 unsigned long mfn, pfn; 670 671 /* Do not add to override if the map failed. */ 672 if (map_ops[i].status) 673 continue; 674 675 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)); 678 mfn = pte_mfn(*pte); 679 } else { 680 mfn = PFN_DOWN(map_ops[i].dev_bus_addr); 681 } 682 pfn = page_to_pfn(pages[i]); 683 684 WARN(pfn_to_mfn(pfn) != INVALID_P2M_ENTRY, "page must be ballooned"); 685 686 if (unlikely(!set_phys_to_machine(pfn, FOREIGN_FRAME(mfn)))) { 687 ret = -ENOMEM; 688 goto out; 689 } 690 } 691 692 out: 693 return ret; 694 } 695 EXPORT_SYMBOL_GPL(set_foreign_p2m_mapping); 696 697 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) 700 { 701 int i, ret = 0; 702 703 if (xen_feature(XENFEAT_auto_translated_physmap)) 704 return 0; 705 706 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]); 709 710 if (mfn == INVALID_P2M_ENTRY || !(mfn & FOREIGN_FRAME_BIT)) { 711 ret = -EINVAL; 712 goto out; 713 } 714 715 set_phys_to_machine(pfn, INVALID_P2M_ENTRY); 716 } 717 if (kunmap_ops) 718 ret = HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, 719 kunmap_ops, count); 720 out: 721 return ret; 722 } 723 EXPORT_SYMBOL_GPL(clear_foreign_p2m_mapping); 724 725 #ifdef CONFIG_XEN_DEBUG_FS 726 #include <linux/debugfs.h> 727 #include "debugfs.h" 728 static int p2m_dump_show(struct seq_file *m, void *v) 729 { 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; 736 int type, prev_type; 737 738 prev_type = xen_p2m_elem_type(0); 739 first_pfn = 0; 740 741 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]); 746 prev_type = type; 747 first_pfn = pfn; 748 } 749 } 750 seq_printf(m, " [0x%lx->0x%lx] %s\n", first_pfn, pfn, 751 type_name[prev_type]); 752 return 0; 753 } 754 755 static int p2m_dump_open(struct inode *inode, struct file *filp) 756 { 757 return single_open(filp, p2m_dump_show, NULL); 758 } 759 760 static const struct file_operations p2m_dump_fops = { 761 .open = p2m_dump_open, 762 .read = seq_read, 763 .llseek = seq_lseek, 764 .release = single_release, 765 }; 766 767 static struct dentry *d_mmu_debug; 768 769 static int __init xen_p2m_debugfs(void) 770 { 771 struct dentry *d_xen = xen_init_debugfs(); 772 773 if (d_xen == NULL) 774 return -ENOMEM; 775 776 d_mmu_debug = debugfs_create_dir("mmu", d_xen); 777 778 debugfs_create_file("p2m", 0600, d_mmu_debug, NULL, &p2m_dump_fops); 779 return 0; 780 } 781 fs_initcall(xen_p2m_debugfs); 782 #endif /* CONFIG_XEN_DEBUG_FS */ 783