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 #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 99 100 static DEFINE_SPINLOCK(p2m_update_lock); 101 102 static unsigned long *p2m_mid_missing_mfn; 103 static unsigned long *p2m_top_mfn; 104 static unsigned long **p2m_top_mfn_p; 105 static unsigned long *p2m_missing; 106 static unsigned long *p2m_identity; 107 static pte_t *p2m_missing_pte; 108 static pte_t *p2m_identity_pte; 109 110 static 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 } 115 116 static inline unsigned p2m_mid_index(unsigned long pfn) 117 { 118 return (pfn / P2M_PER_PAGE) % P2M_MID_PER_PAGE; 119 } 120 121 static inline unsigned p2m_index(unsigned long pfn) 122 { 123 return pfn % P2M_PER_PAGE; 124 } 125 126 static 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 } 133 134 static 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 } 141 142 static 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 } 149 150 static 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 } 157 158 static 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 } 165 166 static 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 } 173 174 static 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 */ 194 void __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 } 254 255 void 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 */ 268 void __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 3 288 289 static 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 } 306 307 static 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 } 390 391 void __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 } 412 413 unsigned 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 } 438 EXPORT_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 */ 446 static 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 */ 505 static 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 } 594 595 unsigned 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 } 617 618 bool __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 } 646 647 bool 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 } 658 659 int 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 } 699 700 out: 701 return ret; 702 } 703 EXPORT_SYMBOL_GPL(set_foreign_p2m_mapping); 704 705 int 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); 728 out: 729 return ret; 730 } 731 EXPORT_SYMBOL_GPL(clear_foreign_p2m_mapping); 732 733 #ifdef CONFIG_XEN_DEBUG_FS 734 #include <linux/debugfs.h> 735 #include "debugfs.h" 736 static 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 } 762 763 static int p2m_dump_open(struct inode *inode, struct file *filp) 764 { 765 return single_open(filp, p2m_dump_show, NULL); 766 } 767 768 static 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 }; 774 775 static struct dentry *d_mmu_debug; 776 777 static 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 } 789 fs_initcall(xen_p2m_debugfs); 790 #endif /* CONFIG_XEN_DEBUG_FS */ 791