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 #include <linux/vmalloc.h> 71 72 #include <asm/cache.h> 73 #include <asm/setup.h> 74 #include <asm/uaccess.h> 75 76 #include <asm/xen/page.h> 77 #include <asm/xen/hypercall.h> 78 #include <asm/xen/hypervisor.h> 79 #include <xen/balloon.h> 80 #include <xen/grant_table.h> 81 82 #include "p2m.h" 83 #include "multicalls.h" 84 #include "xen-ops.h" 85 86 #define PMDS_PER_MID_PAGE (P2M_MID_PER_PAGE / PTRS_PER_PTE) 87 88 unsigned long *xen_p2m_addr __read_mostly; 89 EXPORT_SYMBOL_GPL(xen_p2m_addr); 90 unsigned long xen_p2m_size __read_mostly; 91 EXPORT_SYMBOL_GPL(xen_p2m_size); 92 unsigned long xen_max_p2m_pfn __read_mostly; 93 EXPORT_SYMBOL_GPL(xen_max_p2m_pfn); 94 95 #ifdef CONFIG_XEN_BALLOON_MEMORY_HOTPLUG_LIMIT 96 #define P2M_LIMIT CONFIG_XEN_BALLOON_MEMORY_HOTPLUG_LIMIT 97 #else 98 #define P2M_LIMIT 0 99 #endif 100 101 static DEFINE_SPINLOCK(p2m_update_lock); 102 103 static unsigned long *p2m_mid_missing_mfn; 104 static unsigned long *p2m_top_mfn; 105 static unsigned long **p2m_top_mfn_p; 106 static unsigned long *p2m_missing; 107 static unsigned long *p2m_identity; 108 static pte_t *p2m_missing_pte; 109 static pte_t *p2m_identity_pte; 110 111 static inline unsigned p2m_top_index(unsigned long pfn) 112 { 113 BUG_ON(pfn >= MAX_P2M_PFN); 114 return pfn / (P2M_MID_PER_PAGE * P2M_PER_PAGE); 115 } 116 117 static inline unsigned p2m_mid_index(unsigned long pfn) 118 { 119 return (pfn / P2M_PER_PAGE) % P2M_MID_PER_PAGE; 120 } 121 122 static inline unsigned p2m_index(unsigned long pfn) 123 { 124 return pfn % P2M_PER_PAGE; 125 } 126 127 static void p2m_top_mfn_init(unsigned long *top) 128 { 129 unsigned i; 130 131 for (i = 0; i < P2M_TOP_PER_PAGE; i++) 132 top[i] = virt_to_mfn(p2m_mid_missing_mfn); 133 } 134 135 static void p2m_top_mfn_p_init(unsigned long **top) 136 { 137 unsigned i; 138 139 for (i = 0; i < P2M_TOP_PER_PAGE; i++) 140 top[i] = p2m_mid_missing_mfn; 141 } 142 143 static void p2m_mid_mfn_init(unsigned long *mid, unsigned long *leaf) 144 { 145 unsigned i; 146 147 for (i = 0; i < P2M_MID_PER_PAGE; i++) 148 mid[i] = virt_to_mfn(leaf); 149 } 150 151 static void p2m_init(unsigned long *p2m) 152 { 153 unsigned i; 154 155 for (i = 0; i < P2M_PER_PAGE; i++) 156 p2m[i] = INVALID_P2M_ENTRY; 157 } 158 159 static void p2m_init_identity(unsigned long *p2m, unsigned long pfn) 160 { 161 unsigned i; 162 163 for (i = 0; i < P2M_PER_PAGE; i++) 164 p2m[i] = IDENTITY_FRAME(pfn + i); 165 } 166 167 static void * __ref alloc_p2m_page(void) 168 { 169 if (unlikely(!slab_is_available())) 170 return alloc_bootmem_align(PAGE_SIZE, PAGE_SIZE); 171 172 return (void *)__get_free_page(GFP_KERNEL | __GFP_REPEAT); 173 } 174 175 static void __ref free_p2m_page(void *p) 176 { 177 if (unlikely(!slab_is_available())) { 178 free_bootmem((unsigned long)p, PAGE_SIZE); 179 return; 180 } 181 182 free_page((unsigned long)p); 183 } 184 185 /* 186 * Build the parallel p2m_top_mfn and p2m_mid_mfn structures 187 * 188 * This is called both at boot time, and after resuming from suspend: 189 * - At boot time we're called rather early, and must use alloc_bootmem*() 190 * to allocate memory. 191 * 192 * - After resume we're called from within stop_machine, but the mfn 193 * tree should already be completely allocated. 194 */ 195 void __ref xen_build_mfn_list_list(void) 196 { 197 unsigned long pfn, mfn; 198 pte_t *ptep; 199 unsigned int level, topidx, mididx; 200 unsigned long *mid_mfn_p; 201 202 if (xen_feature(XENFEAT_auto_translated_physmap)) 203 return; 204 205 /* Pre-initialize p2m_top_mfn to be completely missing */ 206 if (p2m_top_mfn == NULL) { 207 p2m_mid_missing_mfn = alloc_p2m_page(); 208 p2m_mid_mfn_init(p2m_mid_missing_mfn, p2m_missing); 209 210 p2m_top_mfn_p = alloc_p2m_page(); 211 p2m_top_mfn_p_init(p2m_top_mfn_p); 212 213 p2m_top_mfn = alloc_p2m_page(); 214 p2m_top_mfn_init(p2m_top_mfn); 215 } else { 216 /* Reinitialise, mfn's all change after migration */ 217 p2m_mid_mfn_init(p2m_mid_missing_mfn, p2m_missing); 218 } 219 220 for (pfn = 0; pfn < xen_max_p2m_pfn && pfn < MAX_P2M_PFN; 221 pfn += P2M_PER_PAGE) { 222 topidx = p2m_top_index(pfn); 223 mididx = p2m_mid_index(pfn); 224 225 mid_mfn_p = p2m_top_mfn_p[topidx]; 226 ptep = lookup_address((unsigned long)(xen_p2m_addr + pfn), 227 &level); 228 BUG_ON(!ptep || level != PG_LEVEL_4K); 229 mfn = pte_mfn(*ptep); 230 ptep = (pte_t *)((unsigned long)ptep & ~(PAGE_SIZE - 1)); 231 232 /* Don't bother allocating any mfn mid levels if 233 * they're just missing, just update the stored mfn, 234 * since all could have changed over a migrate. 235 */ 236 if (ptep == p2m_missing_pte || ptep == p2m_identity_pte) { 237 BUG_ON(mididx); 238 BUG_ON(mid_mfn_p != p2m_mid_missing_mfn); 239 p2m_top_mfn[topidx] = virt_to_mfn(p2m_mid_missing_mfn); 240 pfn += (P2M_MID_PER_PAGE - 1) * P2M_PER_PAGE; 241 continue; 242 } 243 244 if (mid_mfn_p == p2m_mid_missing_mfn) { 245 mid_mfn_p = alloc_p2m_page(); 246 p2m_mid_mfn_init(mid_mfn_p, p2m_missing); 247 248 p2m_top_mfn_p[topidx] = mid_mfn_p; 249 } 250 251 p2m_top_mfn[topidx] = virt_to_mfn(mid_mfn_p); 252 mid_mfn_p[mididx] = mfn; 253 } 254 } 255 256 void xen_setup_mfn_list_list(void) 257 { 258 if (xen_feature(XENFEAT_auto_translated_physmap)) 259 return; 260 261 BUG_ON(HYPERVISOR_shared_info == &xen_dummy_shared_info); 262 263 HYPERVISOR_shared_info->arch.pfn_to_mfn_frame_list_list = 264 virt_to_mfn(p2m_top_mfn); 265 HYPERVISOR_shared_info->arch.max_pfn = xen_max_p2m_pfn; 266 } 267 268 /* Set up p2m_top to point to the domain-builder provided p2m pages */ 269 void __init xen_build_dynamic_phys_to_machine(void) 270 { 271 unsigned long pfn; 272 273 if (xen_feature(XENFEAT_auto_translated_physmap)) 274 return; 275 276 xen_p2m_addr = (unsigned long *)xen_start_info->mfn_list; 277 xen_p2m_size = ALIGN(xen_start_info->nr_pages, P2M_PER_PAGE); 278 279 for (pfn = xen_start_info->nr_pages; pfn < xen_p2m_size; pfn++) 280 xen_p2m_addr[pfn] = INVALID_P2M_ENTRY; 281 282 xen_max_p2m_pfn = xen_p2m_size; 283 } 284 285 #define P2M_TYPE_IDENTITY 0 286 #define P2M_TYPE_MISSING 1 287 #define P2M_TYPE_PFN 2 288 #define P2M_TYPE_UNKNOWN 3 289 290 static int xen_p2m_elem_type(unsigned long pfn) 291 { 292 unsigned long mfn; 293 294 if (pfn >= xen_p2m_size) 295 return P2M_TYPE_IDENTITY; 296 297 mfn = xen_p2m_addr[pfn]; 298 299 if (mfn == INVALID_P2M_ENTRY) 300 return P2M_TYPE_MISSING; 301 302 if (mfn & IDENTITY_FRAME_BIT) 303 return P2M_TYPE_IDENTITY; 304 305 return P2M_TYPE_PFN; 306 } 307 308 static void __init xen_rebuild_p2m_list(unsigned long *p2m) 309 { 310 unsigned int i, chunk; 311 unsigned long pfn; 312 unsigned long *mfns; 313 pte_t *ptep; 314 pmd_t *pmdp; 315 int type; 316 317 p2m_missing = alloc_p2m_page(); 318 p2m_init(p2m_missing); 319 p2m_identity = alloc_p2m_page(); 320 p2m_init(p2m_identity); 321 322 p2m_missing_pte = alloc_p2m_page(); 323 paravirt_alloc_pte(&init_mm, __pa(p2m_missing_pte) >> PAGE_SHIFT); 324 p2m_identity_pte = alloc_p2m_page(); 325 paravirt_alloc_pte(&init_mm, __pa(p2m_identity_pte) >> PAGE_SHIFT); 326 for (i = 0; i < PTRS_PER_PTE; i++) { 327 set_pte(p2m_missing_pte + i, 328 pfn_pte(PFN_DOWN(__pa(p2m_missing)), PAGE_KERNEL_RO)); 329 set_pte(p2m_identity_pte + i, 330 pfn_pte(PFN_DOWN(__pa(p2m_identity)), PAGE_KERNEL_RO)); 331 } 332 333 for (pfn = 0; pfn < xen_max_p2m_pfn; pfn += chunk) { 334 /* 335 * Try to map missing/identity PMDs or p2m-pages if possible. 336 * We have to respect the structure of the mfn_list_list 337 * which will be built just afterwards. 338 * Chunk size to test is one p2m page if we are in the middle 339 * of a mfn_list_list mid page and the complete mid page area 340 * if we are at index 0 of the mid page. Please note that a 341 * mid page might cover more than one PMD, e.g. on 32 bit PAE 342 * kernels. 343 */ 344 chunk = (pfn & (P2M_PER_PAGE * P2M_MID_PER_PAGE - 1)) ? 345 P2M_PER_PAGE : P2M_PER_PAGE * P2M_MID_PER_PAGE; 346 347 type = xen_p2m_elem_type(pfn); 348 i = 0; 349 if (type != P2M_TYPE_PFN) 350 for (i = 1; i < chunk; i++) 351 if (xen_p2m_elem_type(pfn + i) != type) 352 break; 353 if (i < chunk) 354 /* Reset to minimal chunk size. */ 355 chunk = P2M_PER_PAGE; 356 357 if (type == P2M_TYPE_PFN || i < chunk) { 358 /* Use initial p2m page contents. */ 359 #ifdef CONFIG_X86_64 360 mfns = alloc_p2m_page(); 361 copy_page(mfns, xen_p2m_addr + pfn); 362 #else 363 mfns = xen_p2m_addr + pfn; 364 #endif 365 ptep = populate_extra_pte((unsigned long)(p2m + pfn)); 366 set_pte(ptep, 367 pfn_pte(PFN_DOWN(__pa(mfns)), PAGE_KERNEL)); 368 continue; 369 } 370 371 if (chunk == P2M_PER_PAGE) { 372 /* Map complete missing or identity p2m-page. */ 373 mfns = (type == P2M_TYPE_MISSING) ? 374 p2m_missing : p2m_identity; 375 ptep = populate_extra_pte((unsigned long)(p2m + pfn)); 376 set_pte(ptep, 377 pfn_pte(PFN_DOWN(__pa(mfns)), PAGE_KERNEL_RO)); 378 continue; 379 } 380 381 /* Complete missing or identity PMD(s) can be mapped. */ 382 ptep = (type == P2M_TYPE_MISSING) ? 383 p2m_missing_pte : p2m_identity_pte; 384 for (i = 0; i < PMDS_PER_MID_PAGE; i++) { 385 pmdp = populate_extra_pmd( 386 (unsigned long)(p2m + pfn) + i * PMD_SIZE); 387 set_pmd(pmdp, __pmd(__pa(ptep) | _KERNPG_TABLE)); 388 } 389 } 390 } 391 392 void __init xen_vmalloc_p2m_tree(void) 393 { 394 static struct vm_struct vm; 395 unsigned long p2m_limit; 396 397 p2m_limit = (phys_addr_t)P2M_LIMIT * 1024 * 1024 * 1024 / PAGE_SIZE; 398 vm.flags = VM_ALLOC; 399 vm.size = ALIGN(sizeof(unsigned long) * max(xen_max_p2m_pfn, p2m_limit), 400 PMD_SIZE * PMDS_PER_MID_PAGE); 401 vm_area_register_early(&vm, PMD_SIZE * PMDS_PER_MID_PAGE); 402 pr_notice("p2m virtual area at %p, size is %lx\n", vm.addr, vm.size); 403 404 xen_max_p2m_pfn = vm.size / sizeof(unsigned long); 405 406 xen_rebuild_p2m_list(vm.addr); 407 408 xen_p2m_addr = vm.addr; 409 xen_p2m_size = xen_max_p2m_pfn; 410 411 xen_inv_extra_mem(); 412 } 413 414 unsigned long get_phys_to_machine(unsigned long pfn) 415 { 416 pte_t *ptep; 417 unsigned int level; 418 419 if (unlikely(pfn >= xen_p2m_size)) { 420 if (pfn < xen_max_p2m_pfn) 421 return xen_chk_extra_mem(pfn); 422 423 return IDENTITY_FRAME(pfn); 424 } 425 426 ptep = lookup_address((unsigned long)(xen_p2m_addr + pfn), &level); 427 BUG_ON(!ptep || level != PG_LEVEL_4K); 428 429 /* 430 * The INVALID_P2M_ENTRY is filled in both p2m_*identity 431 * and in p2m_*missing, so returning the INVALID_P2M_ENTRY 432 * would be wrong. 433 */ 434 if (pte_pfn(*ptep) == PFN_DOWN(__pa(p2m_identity))) 435 return IDENTITY_FRAME(pfn); 436 437 return xen_p2m_addr[pfn]; 438 } 439 EXPORT_SYMBOL_GPL(get_phys_to_machine); 440 441 /* 442 * Allocate new pmd(s). It is checked whether the old pmd is still in place. 443 * If not, nothing is changed. This is okay as the only reason for allocating 444 * a new pmd is to replace p2m_missing_pte or p2m_identity_pte by a individual 445 * pmd. In case of PAE/x86-32 there are multiple pmds to allocate! 446 */ 447 static pte_t *alloc_p2m_pmd(unsigned long addr, pte_t *pte_pg) 448 { 449 pte_t *ptechk; 450 pte_t *pte_newpg[PMDS_PER_MID_PAGE]; 451 pmd_t *pmdp; 452 unsigned int level; 453 unsigned long flags; 454 unsigned long vaddr; 455 int i; 456 457 /* Do all allocations first to bail out in error case. */ 458 for (i = 0; i < PMDS_PER_MID_PAGE; i++) { 459 pte_newpg[i] = alloc_p2m_page(); 460 if (!pte_newpg[i]) { 461 for (i--; i >= 0; i--) 462 free_p2m_page(pte_newpg[i]); 463 464 return NULL; 465 } 466 } 467 468 vaddr = addr & ~(PMD_SIZE * PMDS_PER_MID_PAGE - 1); 469 470 for (i = 0; i < PMDS_PER_MID_PAGE; i++) { 471 copy_page(pte_newpg[i], pte_pg); 472 paravirt_alloc_pte(&init_mm, __pa(pte_newpg[i]) >> PAGE_SHIFT); 473 474 pmdp = lookup_pmd_address(vaddr); 475 BUG_ON(!pmdp); 476 477 spin_lock_irqsave(&p2m_update_lock, flags); 478 479 ptechk = lookup_address(vaddr, &level); 480 if (ptechk == pte_pg) { 481 set_pmd(pmdp, 482 __pmd(__pa(pte_newpg[i]) | _KERNPG_TABLE)); 483 pte_newpg[i] = NULL; 484 } 485 486 spin_unlock_irqrestore(&p2m_update_lock, flags); 487 488 if (pte_newpg[i]) { 489 paravirt_release_pte(__pa(pte_newpg[i]) >> PAGE_SHIFT); 490 free_p2m_page(pte_newpg[i]); 491 } 492 493 vaddr += PMD_SIZE; 494 } 495 496 return lookup_address(addr, &level); 497 } 498 499 /* 500 * Fully allocate the p2m structure for a given pfn. We need to check 501 * that both the top and mid levels are allocated, and make sure the 502 * parallel mfn tree is kept in sync. We may race with other cpus, so 503 * the new pages are installed with cmpxchg; if we lose the race then 504 * simply free the page we allocated and use the one that's there. 505 */ 506 static bool alloc_p2m(unsigned long pfn) 507 { 508 unsigned topidx, mididx; 509 unsigned long *top_mfn_p, *mid_mfn; 510 pte_t *ptep, *pte_pg; 511 unsigned int level; 512 unsigned long flags; 513 unsigned long addr = (unsigned long)(xen_p2m_addr + pfn); 514 unsigned long p2m_pfn; 515 516 topidx = p2m_top_index(pfn); 517 mididx = p2m_mid_index(pfn); 518 519 ptep = lookup_address(addr, &level); 520 BUG_ON(!ptep || level != PG_LEVEL_4K); 521 pte_pg = (pte_t *)((unsigned long)ptep & ~(PAGE_SIZE - 1)); 522 523 if (pte_pg == p2m_missing_pte || pte_pg == p2m_identity_pte) { 524 /* PMD level is missing, allocate a new one */ 525 ptep = alloc_p2m_pmd(addr, pte_pg); 526 if (!ptep) 527 return false; 528 } 529 530 if (p2m_top_mfn) { 531 top_mfn_p = &p2m_top_mfn[topidx]; 532 mid_mfn = ACCESS_ONCE(p2m_top_mfn_p[topidx]); 533 534 BUG_ON(virt_to_mfn(mid_mfn) != *top_mfn_p); 535 536 if (mid_mfn == p2m_mid_missing_mfn) { 537 /* Separately check the mid mfn level */ 538 unsigned long missing_mfn; 539 unsigned long mid_mfn_mfn; 540 unsigned long old_mfn; 541 542 mid_mfn = alloc_p2m_page(); 543 if (!mid_mfn) 544 return false; 545 546 p2m_mid_mfn_init(mid_mfn, p2m_missing); 547 548 missing_mfn = virt_to_mfn(p2m_mid_missing_mfn); 549 mid_mfn_mfn = virt_to_mfn(mid_mfn); 550 old_mfn = cmpxchg(top_mfn_p, missing_mfn, mid_mfn_mfn); 551 if (old_mfn != missing_mfn) { 552 free_p2m_page(mid_mfn); 553 mid_mfn = mfn_to_virt(old_mfn); 554 } else { 555 p2m_top_mfn_p[topidx] = mid_mfn; 556 } 557 } 558 } else { 559 mid_mfn = NULL; 560 } 561 562 p2m_pfn = pte_pfn(READ_ONCE(*ptep)); 563 if (p2m_pfn == PFN_DOWN(__pa(p2m_identity)) || 564 p2m_pfn == PFN_DOWN(__pa(p2m_missing))) { 565 /* p2m leaf page is missing */ 566 unsigned long *p2m; 567 568 p2m = alloc_p2m_page(); 569 if (!p2m) 570 return false; 571 572 if (p2m_pfn == PFN_DOWN(__pa(p2m_missing))) 573 p2m_init(p2m); 574 else 575 p2m_init_identity(p2m, pfn & ~(P2M_PER_PAGE - 1)); 576 577 spin_lock_irqsave(&p2m_update_lock, flags); 578 579 if (pte_pfn(*ptep) == p2m_pfn) { 580 set_pte(ptep, 581 pfn_pte(PFN_DOWN(__pa(p2m)), PAGE_KERNEL)); 582 if (mid_mfn) 583 mid_mfn[mididx] = virt_to_mfn(p2m); 584 p2m = NULL; 585 } 586 587 spin_unlock_irqrestore(&p2m_update_lock, flags); 588 589 if (p2m) 590 free_p2m_page(p2m); 591 } 592 593 return true; 594 } 595 596 unsigned long __init set_phys_range_identity(unsigned long pfn_s, 597 unsigned long pfn_e) 598 { 599 unsigned long pfn; 600 601 if (unlikely(pfn_s >= xen_p2m_size)) 602 return 0; 603 604 if (unlikely(xen_feature(XENFEAT_auto_translated_physmap))) 605 return pfn_e - pfn_s; 606 607 if (pfn_s > pfn_e) 608 return 0; 609 610 if (pfn_e > xen_p2m_size) 611 pfn_e = xen_p2m_size; 612 613 for (pfn = pfn_s; pfn < pfn_e; pfn++) 614 xen_p2m_addr[pfn] = IDENTITY_FRAME(pfn); 615 616 return pfn - pfn_s; 617 } 618 619 bool __set_phys_to_machine(unsigned long pfn, unsigned long mfn) 620 { 621 pte_t *ptep; 622 unsigned int level; 623 624 /* don't track P2M changes in autotranslate guests */ 625 if (unlikely(xen_feature(XENFEAT_auto_translated_physmap))) 626 return true; 627 628 if (unlikely(pfn >= xen_p2m_size)) { 629 BUG_ON(mfn != INVALID_P2M_ENTRY); 630 return true; 631 } 632 633 if (likely(!xen_safe_write_ulong(xen_p2m_addr + pfn, mfn))) 634 return true; 635 636 ptep = lookup_address((unsigned long)(xen_p2m_addr + pfn), &level); 637 BUG_ON(!ptep || level != PG_LEVEL_4K); 638 639 if (pte_pfn(*ptep) == PFN_DOWN(__pa(p2m_missing))) 640 return mfn == INVALID_P2M_ENTRY; 641 642 if (pte_pfn(*ptep) == PFN_DOWN(__pa(p2m_identity))) 643 return mfn == IDENTITY_FRAME(pfn); 644 645 return false; 646 } 647 648 bool set_phys_to_machine(unsigned long pfn, unsigned long mfn) 649 { 650 if (unlikely(!__set_phys_to_machine(pfn, mfn))) { 651 if (!alloc_p2m(pfn)) 652 return false; 653 654 return __set_phys_to_machine(pfn, mfn); 655 } 656 657 return true; 658 } 659 660 int set_foreign_p2m_mapping(struct gnttab_map_grant_ref *map_ops, 661 struct gnttab_map_grant_ref *kmap_ops, 662 struct page **pages, unsigned int count) 663 { 664 int i, ret = 0; 665 pte_t *pte; 666 667 if (xen_feature(XENFEAT_auto_translated_physmap)) 668 return 0; 669 670 if (kmap_ops) { 671 ret = HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, 672 kmap_ops, count); 673 if (ret) 674 goto out; 675 } 676 677 for (i = 0; i < count; i++) { 678 unsigned long mfn, pfn; 679 680 /* Do not add to override if the map failed. */ 681 if (map_ops[i].status) 682 continue; 683 684 if (map_ops[i].flags & GNTMAP_contains_pte) { 685 pte = (pte_t *)(mfn_to_virt(PFN_DOWN(map_ops[i].host_addr)) + 686 (map_ops[i].host_addr & ~PAGE_MASK)); 687 mfn = pte_mfn(*pte); 688 } else { 689 mfn = PFN_DOWN(map_ops[i].dev_bus_addr); 690 } 691 pfn = page_to_pfn(pages[i]); 692 693 WARN(pfn_to_mfn(pfn) != INVALID_P2M_ENTRY, "page must be ballooned"); 694 695 if (unlikely(!set_phys_to_machine(pfn, FOREIGN_FRAME(mfn)))) { 696 ret = -ENOMEM; 697 goto out; 698 } 699 } 700 701 out: 702 return ret; 703 } 704 EXPORT_SYMBOL_GPL(set_foreign_p2m_mapping); 705 706 int clear_foreign_p2m_mapping(struct gnttab_unmap_grant_ref *unmap_ops, 707 struct gnttab_unmap_grant_ref *kunmap_ops, 708 struct page **pages, unsigned int count) 709 { 710 int i, ret = 0; 711 712 if (xen_feature(XENFEAT_auto_translated_physmap)) 713 return 0; 714 715 for (i = 0; i < count; i++) { 716 unsigned long mfn = __pfn_to_mfn(page_to_pfn(pages[i])); 717 unsigned long pfn = page_to_pfn(pages[i]); 718 719 if (mfn == INVALID_P2M_ENTRY || !(mfn & FOREIGN_FRAME_BIT)) { 720 ret = -EINVAL; 721 goto out; 722 } 723 724 set_phys_to_machine(pfn, INVALID_P2M_ENTRY); 725 } 726 if (kunmap_ops) 727 ret = HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, 728 kunmap_ops, count); 729 out: 730 return ret; 731 } 732 EXPORT_SYMBOL_GPL(clear_foreign_p2m_mapping); 733 734 #ifdef CONFIG_XEN_DEBUG_FS 735 #include <linux/debugfs.h> 736 #include "debugfs.h" 737 static int p2m_dump_show(struct seq_file *m, void *v) 738 { 739 static const char * const type_name[] = { 740 [P2M_TYPE_IDENTITY] = "identity", 741 [P2M_TYPE_MISSING] = "missing", 742 [P2M_TYPE_PFN] = "pfn", 743 [P2M_TYPE_UNKNOWN] = "abnormal"}; 744 unsigned long pfn, first_pfn; 745 int type, prev_type; 746 747 prev_type = xen_p2m_elem_type(0); 748 first_pfn = 0; 749 750 for (pfn = 0; pfn < xen_p2m_size; pfn++) { 751 type = xen_p2m_elem_type(pfn); 752 if (type != prev_type) { 753 seq_printf(m, " [0x%lx->0x%lx] %s\n", first_pfn, pfn, 754 type_name[prev_type]); 755 prev_type = type; 756 first_pfn = pfn; 757 } 758 } 759 seq_printf(m, " [0x%lx->0x%lx] %s\n", first_pfn, pfn, 760 type_name[prev_type]); 761 return 0; 762 } 763 764 static int p2m_dump_open(struct inode *inode, struct file *filp) 765 { 766 return single_open(filp, p2m_dump_show, NULL); 767 } 768 769 static const struct file_operations p2m_dump_fops = { 770 .open = p2m_dump_open, 771 .read = seq_read, 772 .llseek = seq_lseek, 773 .release = single_release, 774 }; 775 776 static struct dentry *d_mmu_debug; 777 778 static int __init xen_p2m_debugfs(void) 779 { 780 struct dentry *d_xen = xen_init_debugfs(); 781 782 if (d_xen == NULL) 783 return -ENOMEM; 784 785 d_mmu_debug = debugfs_create_dir("mmu", d_xen); 786 787 debugfs_create_file("p2m", 0600, d_mmu_debug, NULL, &p2m_dump_fops); 788 return 0; 789 } 790 fs_initcall(xen_p2m_debugfs); 791 #endif /* CONFIG_XEN_DEBUG_FS */ 792