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 "multicalls.h" 83 #include "xen-ops.h" 84 85 #define P2M_MID_PER_PAGE (PAGE_SIZE / sizeof(unsigned long *)) 86 #define P2M_TOP_PER_PAGE (PAGE_SIZE / sizeof(unsigned long **)) 87 88 #define MAX_P2M_PFN (P2M_TOP_PER_PAGE * P2M_MID_PER_PAGE * P2M_PER_PAGE) 89 90 #define PMDS_PER_MID_PAGE (P2M_MID_PER_PAGE / PTRS_PER_PTE) 91 92 unsigned long *xen_p2m_addr __read_mostly; 93 EXPORT_SYMBOL_GPL(xen_p2m_addr); 94 unsigned long xen_p2m_size __read_mostly; 95 EXPORT_SYMBOL_GPL(xen_p2m_size); 96 unsigned long xen_max_p2m_pfn __read_mostly; 97 EXPORT_SYMBOL_GPL(xen_max_p2m_pfn); 98 99 #ifdef CONFIG_XEN_BALLOON_MEMORY_HOTPLUG_LIMIT 100 #define P2M_LIMIT CONFIG_XEN_BALLOON_MEMORY_HOTPLUG_LIMIT 101 #else 102 #define P2M_LIMIT 0 103 #endif 104 105 static DEFINE_SPINLOCK(p2m_update_lock); 106 107 static unsigned long *p2m_mid_missing_mfn; 108 static unsigned long *p2m_top_mfn; 109 static unsigned long **p2m_top_mfn_p; 110 static unsigned long *p2m_missing; 111 static unsigned long *p2m_identity; 112 static pte_t *p2m_missing_pte; 113 static pte_t *p2m_identity_pte; 114 115 /* 116 * Hint at last populated PFN. 117 * 118 * Used to set HYPERVISOR_shared_info->arch.max_pfn so the toolstack 119 * can avoid scanning the whole P2M (which may be sized to account for 120 * hotplugged memory). 121 */ 122 static unsigned long xen_p2m_last_pfn; 123 124 static inline unsigned p2m_top_index(unsigned long pfn) 125 { 126 BUG_ON(pfn >= MAX_P2M_PFN); 127 return pfn / (P2M_MID_PER_PAGE * P2M_PER_PAGE); 128 } 129 130 static inline unsigned p2m_mid_index(unsigned long pfn) 131 { 132 return (pfn / P2M_PER_PAGE) % P2M_MID_PER_PAGE; 133 } 134 135 static inline unsigned p2m_index(unsigned long pfn) 136 { 137 return pfn % P2M_PER_PAGE; 138 } 139 140 static void p2m_top_mfn_init(unsigned long *top) 141 { 142 unsigned i; 143 144 for (i = 0; i < P2M_TOP_PER_PAGE; i++) 145 top[i] = virt_to_mfn(p2m_mid_missing_mfn); 146 } 147 148 static void p2m_top_mfn_p_init(unsigned long **top) 149 { 150 unsigned i; 151 152 for (i = 0; i < P2M_TOP_PER_PAGE; i++) 153 top[i] = p2m_mid_missing_mfn; 154 } 155 156 static void p2m_mid_mfn_init(unsigned long *mid, unsigned long *leaf) 157 { 158 unsigned i; 159 160 for (i = 0; i < P2M_MID_PER_PAGE; i++) 161 mid[i] = virt_to_mfn(leaf); 162 } 163 164 static void p2m_init(unsigned long *p2m) 165 { 166 unsigned i; 167 168 for (i = 0; i < P2M_PER_PAGE; i++) 169 p2m[i] = INVALID_P2M_ENTRY; 170 } 171 172 static void p2m_init_identity(unsigned long *p2m, unsigned long pfn) 173 { 174 unsigned i; 175 176 for (i = 0; i < P2M_PER_PAGE; i++) 177 p2m[i] = IDENTITY_FRAME(pfn + i); 178 } 179 180 static void * __ref alloc_p2m_page(void) 181 { 182 if (unlikely(!slab_is_available())) 183 return alloc_bootmem_align(PAGE_SIZE, PAGE_SIZE); 184 185 return (void *)__get_free_page(GFP_KERNEL); 186 } 187 188 static void __ref free_p2m_page(void *p) 189 { 190 if (unlikely(!slab_is_available())) { 191 free_bootmem((unsigned long)p, PAGE_SIZE); 192 return; 193 } 194 195 free_page((unsigned long)p); 196 } 197 198 /* 199 * Build the parallel p2m_top_mfn and p2m_mid_mfn structures 200 * 201 * This is called both at boot time, and after resuming from suspend: 202 * - At boot time we're called rather early, and must use alloc_bootmem*() 203 * to allocate memory. 204 * 205 * - After resume we're called from within stop_machine, but the mfn 206 * tree should already be completely allocated. 207 */ 208 void __ref xen_build_mfn_list_list(void) 209 { 210 unsigned long pfn, mfn; 211 pte_t *ptep; 212 unsigned int level, topidx, mididx; 213 unsigned long *mid_mfn_p; 214 215 if (xen_feature(XENFEAT_auto_translated_physmap) || 216 xen_start_info->flags & SIF_VIRT_P2M_4TOOLS) 217 return; 218 219 /* Pre-initialize p2m_top_mfn to be completely missing */ 220 if (p2m_top_mfn == NULL) { 221 p2m_mid_missing_mfn = alloc_p2m_page(); 222 p2m_mid_mfn_init(p2m_mid_missing_mfn, p2m_missing); 223 224 p2m_top_mfn_p = alloc_p2m_page(); 225 p2m_top_mfn_p_init(p2m_top_mfn_p); 226 227 p2m_top_mfn = alloc_p2m_page(); 228 p2m_top_mfn_init(p2m_top_mfn); 229 } else { 230 /* Reinitialise, mfn's all change after migration */ 231 p2m_mid_mfn_init(p2m_mid_missing_mfn, p2m_missing); 232 } 233 234 for (pfn = 0; pfn < xen_max_p2m_pfn && pfn < MAX_P2M_PFN; 235 pfn += P2M_PER_PAGE) { 236 topidx = p2m_top_index(pfn); 237 mididx = p2m_mid_index(pfn); 238 239 mid_mfn_p = p2m_top_mfn_p[topidx]; 240 ptep = lookup_address((unsigned long)(xen_p2m_addr + pfn), 241 &level); 242 BUG_ON(!ptep || level != PG_LEVEL_4K); 243 mfn = pte_mfn(*ptep); 244 ptep = (pte_t *)((unsigned long)ptep & ~(PAGE_SIZE - 1)); 245 246 /* Don't bother allocating any mfn mid levels if 247 * they're just missing, just update the stored mfn, 248 * since all could have changed over a migrate. 249 */ 250 if (ptep == p2m_missing_pte || ptep == p2m_identity_pte) { 251 BUG_ON(mididx); 252 BUG_ON(mid_mfn_p != p2m_mid_missing_mfn); 253 p2m_top_mfn[topidx] = virt_to_mfn(p2m_mid_missing_mfn); 254 pfn += (P2M_MID_PER_PAGE - 1) * P2M_PER_PAGE; 255 continue; 256 } 257 258 if (mid_mfn_p == p2m_mid_missing_mfn) { 259 mid_mfn_p = alloc_p2m_page(); 260 p2m_mid_mfn_init(mid_mfn_p, p2m_missing); 261 262 p2m_top_mfn_p[topidx] = mid_mfn_p; 263 } 264 265 p2m_top_mfn[topidx] = virt_to_mfn(mid_mfn_p); 266 mid_mfn_p[mididx] = mfn; 267 } 268 } 269 270 void xen_setup_mfn_list_list(void) 271 { 272 if (xen_feature(XENFEAT_auto_translated_physmap)) 273 return; 274 275 BUG_ON(HYPERVISOR_shared_info == &xen_dummy_shared_info); 276 277 if (xen_start_info->flags & SIF_VIRT_P2M_4TOOLS) 278 HYPERVISOR_shared_info->arch.pfn_to_mfn_frame_list_list = ~0UL; 279 else 280 HYPERVISOR_shared_info->arch.pfn_to_mfn_frame_list_list = 281 virt_to_mfn(p2m_top_mfn); 282 HYPERVISOR_shared_info->arch.max_pfn = xen_p2m_last_pfn; 283 HYPERVISOR_shared_info->arch.p2m_generation = 0; 284 HYPERVISOR_shared_info->arch.p2m_vaddr = (unsigned long)xen_p2m_addr; 285 HYPERVISOR_shared_info->arch.p2m_cr3 = 286 xen_pfn_to_cr3(virt_to_mfn(swapper_pg_dir)); 287 } 288 289 /* Set up p2m_top to point to the domain-builder provided p2m pages */ 290 void __init xen_build_dynamic_phys_to_machine(void) 291 { 292 unsigned long pfn; 293 294 if (xen_feature(XENFEAT_auto_translated_physmap)) 295 return; 296 297 xen_p2m_addr = (unsigned long *)xen_start_info->mfn_list; 298 xen_p2m_size = ALIGN(xen_start_info->nr_pages, P2M_PER_PAGE); 299 300 for (pfn = xen_start_info->nr_pages; pfn < xen_p2m_size; pfn++) 301 xen_p2m_addr[pfn] = INVALID_P2M_ENTRY; 302 303 xen_max_p2m_pfn = xen_p2m_size; 304 } 305 306 #define P2M_TYPE_IDENTITY 0 307 #define P2M_TYPE_MISSING 1 308 #define P2M_TYPE_PFN 2 309 #define P2M_TYPE_UNKNOWN 3 310 311 static int xen_p2m_elem_type(unsigned long pfn) 312 { 313 unsigned long mfn; 314 315 if (pfn >= xen_p2m_size) 316 return P2M_TYPE_IDENTITY; 317 318 mfn = xen_p2m_addr[pfn]; 319 320 if (mfn == INVALID_P2M_ENTRY) 321 return P2M_TYPE_MISSING; 322 323 if (mfn & IDENTITY_FRAME_BIT) 324 return P2M_TYPE_IDENTITY; 325 326 return P2M_TYPE_PFN; 327 } 328 329 static void __init xen_rebuild_p2m_list(unsigned long *p2m) 330 { 331 unsigned int i, chunk; 332 unsigned long pfn; 333 unsigned long *mfns; 334 pte_t *ptep; 335 pmd_t *pmdp; 336 int type; 337 338 p2m_missing = alloc_p2m_page(); 339 p2m_init(p2m_missing); 340 p2m_identity = alloc_p2m_page(); 341 p2m_init(p2m_identity); 342 343 p2m_missing_pte = alloc_p2m_page(); 344 paravirt_alloc_pte(&init_mm, __pa(p2m_missing_pte) >> PAGE_SHIFT); 345 p2m_identity_pte = alloc_p2m_page(); 346 paravirt_alloc_pte(&init_mm, __pa(p2m_identity_pte) >> PAGE_SHIFT); 347 for (i = 0; i < PTRS_PER_PTE; i++) { 348 set_pte(p2m_missing_pte + i, 349 pfn_pte(PFN_DOWN(__pa(p2m_missing)), PAGE_KERNEL_RO)); 350 set_pte(p2m_identity_pte + i, 351 pfn_pte(PFN_DOWN(__pa(p2m_identity)), PAGE_KERNEL_RO)); 352 } 353 354 for (pfn = 0; pfn < xen_max_p2m_pfn; pfn += chunk) { 355 /* 356 * Try to map missing/identity PMDs or p2m-pages if possible. 357 * We have to respect the structure of the mfn_list_list 358 * which will be built just afterwards. 359 * Chunk size to test is one p2m page if we are in the middle 360 * of a mfn_list_list mid page and the complete mid page area 361 * if we are at index 0 of the mid page. Please note that a 362 * mid page might cover more than one PMD, e.g. on 32 bit PAE 363 * kernels. 364 */ 365 chunk = (pfn & (P2M_PER_PAGE * P2M_MID_PER_PAGE - 1)) ? 366 P2M_PER_PAGE : P2M_PER_PAGE * P2M_MID_PER_PAGE; 367 368 type = xen_p2m_elem_type(pfn); 369 i = 0; 370 if (type != P2M_TYPE_PFN) 371 for (i = 1; i < chunk; i++) 372 if (xen_p2m_elem_type(pfn + i) != type) 373 break; 374 if (i < chunk) 375 /* Reset to minimal chunk size. */ 376 chunk = P2M_PER_PAGE; 377 378 if (type == P2M_TYPE_PFN || i < chunk) { 379 /* Use initial p2m page contents. */ 380 #ifdef CONFIG_X86_64 381 mfns = alloc_p2m_page(); 382 copy_page(mfns, xen_p2m_addr + pfn); 383 #else 384 mfns = xen_p2m_addr + pfn; 385 #endif 386 ptep = populate_extra_pte((unsigned long)(p2m + pfn)); 387 set_pte(ptep, 388 pfn_pte(PFN_DOWN(__pa(mfns)), PAGE_KERNEL)); 389 continue; 390 } 391 392 if (chunk == P2M_PER_PAGE) { 393 /* Map complete missing or identity p2m-page. */ 394 mfns = (type == P2M_TYPE_MISSING) ? 395 p2m_missing : p2m_identity; 396 ptep = populate_extra_pte((unsigned long)(p2m + pfn)); 397 set_pte(ptep, 398 pfn_pte(PFN_DOWN(__pa(mfns)), PAGE_KERNEL_RO)); 399 continue; 400 } 401 402 /* Complete missing or identity PMD(s) can be mapped. */ 403 ptep = (type == P2M_TYPE_MISSING) ? 404 p2m_missing_pte : p2m_identity_pte; 405 for (i = 0; i < PMDS_PER_MID_PAGE; i++) { 406 pmdp = populate_extra_pmd( 407 (unsigned long)(p2m + pfn) + i * PMD_SIZE); 408 set_pmd(pmdp, __pmd(__pa(ptep) | _KERNPG_TABLE)); 409 } 410 } 411 } 412 413 void __init xen_vmalloc_p2m_tree(void) 414 { 415 static struct vm_struct vm; 416 unsigned long p2m_limit; 417 418 xen_p2m_last_pfn = xen_max_p2m_pfn; 419 420 p2m_limit = (phys_addr_t)P2M_LIMIT * 1024 * 1024 * 1024 / PAGE_SIZE; 421 vm.flags = VM_ALLOC; 422 vm.size = ALIGN(sizeof(unsigned long) * max(xen_max_p2m_pfn, p2m_limit), 423 PMD_SIZE * PMDS_PER_MID_PAGE); 424 vm_area_register_early(&vm, PMD_SIZE * PMDS_PER_MID_PAGE); 425 pr_notice("p2m virtual area at %p, size is %lx\n", vm.addr, vm.size); 426 427 xen_max_p2m_pfn = vm.size / sizeof(unsigned long); 428 429 xen_rebuild_p2m_list(vm.addr); 430 431 xen_p2m_addr = vm.addr; 432 xen_p2m_size = xen_max_p2m_pfn; 433 434 xen_inv_extra_mem(); 435 } 436 437 unsigned long get_phys_to_machine(unsigned long pfn) 438 { 439 pte_t *ptep; 440 unsigned int level; 441 442 if (unlikely(pfn >= xen_p2m_size)) { 443 if (pfn < xen_max_p2m_pfn) 444 return xen_chk_extra_mem(pfn); 445 446 return IDENTITY_FRAME(pfn); 447 } 448 449 ptep = lookup_address((unsigned long)(xen_p2m_addr + pfn), &level); 450 BUG_ON(!ptep || level != PG_LEVEL_4K); 451 452 /* 453 * The INVALID_P2M_ENTRY is filled in both p2m_*identity 454 * and in p2m_*missing, so returning the INVALID_P2M_ENTRY 455 * would be wrong. 456 */ 457 if (pte_pfn(*ptep) == PFN_DOWN(__pa(p2m_identity))) 458 return IDENTITY_FRAME(pfn); 459 460 return xen_p2m_addr[pfn]; 461 } 462 EXPORT_SYMBOL_GPL(get_phys_to_machine); 463 464 /* 465 * Allocate new pmd(s). It is checked whether the old pmd is still in place. 466 * If not, nothing is changed. This is okay as the only reason for allocating 467 * a new pmd is to replace p2m_missing_pte or p2m_identity_pte by a individual 468 * pmd. In case of PAE/x86-32 there are multiple pmds to allocate! 469 */ 470 static pte_t *alloc_p2m_pmd(unsigned long addr, pte_t *pte_pg) 471 { 472 pte_t *ptechk; 473 pte_t *pte_newpg[PMDS_PER_MID_PAGE]; 474 pmd_t *pmdp; 475 unsigned int level; 476 unsigned long flags; 477 unsigned long vaddr; 478 int i; 479 480 /* Do all allocations first to bail out in error case. */ 481 for (i = 0; i < PMDS_PER_MID_PAGE; i++) { 482 pte_newpg[i] = alloc_p2m_page(); 483 if (!pte_newpg[i]) { 484 for (i--; i >= 0; i--) 485 free_p2m_page(pte_newpg[i]); 486 487 return NULL; 488 } 489 } 490 491 vaddr = addr & ~(PMD_SIZE * PMDS_PER_MID_PAGE - 1); 492 493 for (i = 0; i < PMDS_PER_MID_PAGE; i++) { 494 copy_page(pte_newpg[i], pte_pg); 495 paravirt_alloc_pte(&init_mm, __pa(pte_newpg[i]) >> PAGE_SHIFT); 496 497 pmdp = lookup_pmd_address(vaddr); 498 BUG_ON(!pmdp); 499 500 spin_lock_irqsave(&p2m_update_lock, flags); 501 502 ptechk = lookup_address(vaddr, &level); 503 if (ptechk == pte_pg) { 504 HYPERVISOR_shared_info->arch.p2m_generation++; 505 wmb(); /* Tools are synchronizing via p2m_generation. */ 506 set_pmd(pmdp, 507 __pmd(__pa(pte_newpg[i]) | _KERNPG_TABLE)); 508 wmb(); /* Tools are synchronizing via p2m_generation. */ 509 HYPERVISOR_shared_info->arch.p2m_generation++; 510 pte_newpg[i] = NULL; 511 } 512 513 spin_unlock_irqrestore(&p2m_update_lock, flags); 514 515 if (pte_newpg[i]) { 516 paravirt_release_pte(__pa(pte_newpg[i]) >> PAGE_SHIFT); 517 free_p2m_page(pte_newpg[i]); 518 } 519 520 vaddr += PMD_SIZE; 521 } 522 523 return lookup_address(addr, &level); 524 } 525 526 /* 527 * Fully allocate the p2m structure for a given pfn. We need to check 528 * that both the top and mid levels are allocated, and make sure the 529 * parallel mfn tree is kept in sync. We may race with other cpus, so 530 * the new pages are installed with cmpxchg; if we lose the race then 531 * simply free the page we allocated and use the one that's there. 532 */ 533 int xen_alloc_p2m_entry(unsigned long pfn) 534 { 535 unsigned topidx; 536 unsigned long *top_mfn_p, *mid_mfn; 537 pte_t *ptep, *pte_pg; 538 unsigned int level; 539 unsigned long flags; 540 unsigned long addr = (unsigned long)(xen_p2m_addr + pfn); 541 unsigned long p2m_pfn; 542 543 if (xen_feature(XENFEAT_auto_translated_physmap)) 544 return 0; 545 546 ptep = lookup_address(addr, &level); 547 BUG_ON(!ptep || level != PG_LEVEL_4K); 548 pte_pg = (pte_t *)((unsigned long)ptep & ~(PAGE_SIZE - 1)); 549 550 if (pte_pg == p2m_missing_pte || pte_pg == p2m_identity_pte) { 551 /* PMD level is missing, allocate a new one */ 552 ptep = alloc_p2m_pmd(addr, pte_pg); 553 if (!ptep) 554 return -ENOMEM; 555 } 556 557 if (p2m_top_mfn && pfn < MAX_P2M_PFN) { 558 topidx = p2m_top_index(pfn); 559 top_mfn_p = &p2m_top_mfn[topidx]; 560 mid_mfn = ACCESS_ONCE(p2m_top_mfn_p[topidx]); 561 562 BUG_ON(virt_to_mfn(mid_mfn) != *top_mfn_p); 563 564 if (mid_mfn == p2m_mid_missing_mfn) { 565 /* Separately check the mid mfn level */ 566 unsigned long missing_mfn; 567 unsigned long mid_mfn_mfn; 568 unsigned long old_mfn; 569 570 mid_mfn = alloc_p2m_page(); 571 if (!mid_mfn) 572 return -ENOMEM; 573 574 p2m_mid_mfn_init(mid_mfn, p2m_missing); 575 576 missing_mfn = virt_to_mfn(p2m_mid_missing_mfn); 577 mid_mfn_mfn = virt_to_mfn(mid_mfn); 578 old_mfn = cmpxchg(top_mfn_p, missing_mfn, mid_mfn_mfn); 579 if (old_mfn != missing_mfn) { 580 free_p2m_page(mid_mfn); 581 mid_mfn = mfn_to_virt(old_mfn); 582 } else { 583 p2m_top_mfn_p[topidx] = mid_mfn; 584 } 585 } 586 } else { 587 mid_mfn = NULL; 588 } 589 590 p2m_pfn = pte_pfn(READ_ONCE(*ptep)); 591 if (p2m_pfn == PFN_DOWN(__pa(p2m_identity)) || 592 p2m_pfn == PFN_DOWN(__pa(p2m_missing))) { 593 /* p2m leaf page is missing */ 594 unsigned long *p2m; 595 596 p2m = alloc_p2m_page(); 597 if (!p2m) 598 return -ENOMEM; 599 600 if (p2m_pfn == PFN_DOWN(__pa(p2m_missing))) 601 p2m_init(p2m); 602 else 603 p2m_init_identity(p2m, pfn & ~(P2M_PER_PAGE - 1)); 604 605 spin_lock_irqsave(&p2m_update_lock, flags); 606 607 if (pte_pfn(*ptep) == p2m_pfn) { 608 HYPERVISOR_shared_info->arch.p2m_generation++; 609 wmb(); /* Tools are synchronizing via p2m_generation. */ 610 set_pte(ptep, 611 pfn_pte(PFN_DOWN(__pa(p2m)), PAGE_KERNEL)); 612 wmb(); /* Tools are synchronizing via p2m_generation. */ 613 HYPERVISOR_shared_info->arch.p2m_generation++; 614 if (mid_mfn) 615 mid_mfn[p2m_mid_index(pfn)] = virt_to_mfn(p2m); 616 p2m = NULL; 617 } 618 619 spin_unlock_irqrestore(&p2m_update_lock, flags); 620 621 if (p2m) 622 free_p2m_page(p2m); 623 } 624 625 /* Expanded the p2m? */ 626 if (pfn > xen_p2m_last_pfn) { 627 xen_p2m_last_pfn = pfn; 628 HYPERVISOR_shared_info->arch.max_pfn = xen_p2m_last_pfn; 629 } 630 631 return 0; 632 } 633 EXPORT_SYMBOL(xen_alloc_p2m_entry); 634 635 unsigned long __init set_phys_range_identity(unsigned long pfn_s, 636 unsigned long pfn_e) 637 { 638 unsigned long pfn; 639 640 if (unlikely(pfn_s >= xen_p2m_size)) 641 return 0; 642 643 if (unlikely(xen_feature(XENFEAT_auto_translated_physmap))) 644 return pfn_e - pfn_s; 645 646 if (pfn_s > pfn_e) 647 return 0; 648 649 if (pfn_e > xen_p2m_size) 650 pfn_e = xen_p2m_size; 651 652 for (pfn = pfn_s; pfn < pfn_e; pfn++) 653 xen_p2m_addr[pfn] = IDENTITY_FRAME(pfn); 654 655 return pfn - pfn_s; 656 } 657 658 bool __set_phys_to_machine(unsigned long pfn, unsigned long mfn) 659 { 660 pte_t *ptep; 661 unsigned int level; 662 663 /* don't track P2M changes in autotranslate guests */ 664 if (unlikely(xen_feature(XENFEAT_auto_translated_physmap))) 665 return true; 666 667 if (unlikely(pfn >= xen_p2m_size)) { 668 BUG_ON(mfn != INVALID_P2M_ENTRY); 669 return true; 670 } 671 672 /* 673 * The interface requires atomic updates on p2m elements. 674 * xen_safe_write_ulong() is using __put_user which does an atomic 675 * store via asm(). 676 */ 677 if (likely(!xen_safe_write_ulong(xen_p2m_addr + pfn, mfn))) 678 return true; 679 680 ptep = lookup_address((unsigned long)(xen_p2m_addr + pfn), &level); 681 BUG_ON(!ptep || level != PG_LEVEL_4K); 682 683 if (pte_pfn(*ptep) == PFN_DOWN(__pa(p2m_missing))) 684 return mfn == INVALID_P2M_ENTRY; 685 686 if (pte_pfn(*ptep) == PFN_DOWN(__pa(p2m_identity))) 687 return mfn == IDENTITY_FRAME(pfn); 688 689 return false; 690 } 691 692 bool set_phys_to_machine(unsigned long pfn, unsigned long mfn) 693 { 694 if (unlikely(!__set_phys_to_machine(pfn, mfn))) { 695 int ret; 696 697 ret = xen_alloc_p2m_entry(pfn); 698 if (ret < 0) 699 return false; 700 701 return __set_phys_to_machine(pfn, mfn); 702 } 703 704 return true; 705 } 706 707 int set_foreign_p2m_mapping(struct gnttab_map_grant_ref *map_ops, 708 struct gnttab_map_grant_ref *kmap_ops, 709 struct page **pages, unsigned int count) 710 { 711 int i, ret = 0; 712 pte_t *pte; 713 714 if (xen_feature(XENFEAT_auto_translated_physmap)) 715 return 0; 716 717 if (kmap_ops) { 718 ret = HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, 719 kmap_ops, count); 720 if (ret) 721 goto out; 722 } 723 724 for (i = 0; i < count; i++) { 725 unsigned long mfn, pfn; 726 727 /* Do not add to override if the map failed. */ 728 if (map_ops[i].status) 729 continue; 730 731 if (map_ops[i].flags & GNTMAP_contains_pte) { 732 pte = (pte_t *)(mfn_to_virt(PFN_DOWN(map_ops[i].host_addr)) + 733 (map_ops[i].host_addr & ~PAGE_MASK)); 734 mfn = pte_mfn(*pte); 735 } else { 736 mfn = PFN_DOWN(map_ops[i].dev_bus_addr); 737 } 738 pfn = page_to_pfn(pages[i]); 739 740 WARN(pfn_to_mfn(pfn) != INVALID_P2M_ENTRY, "page must be ballooned"); 741 742 if (unlikely(!set_phys_to_machine(pfn, FOREIGN_FRAME(mfn)))) { 743 ret = -ENOMEM; 744 goto out; 745 } 746 } 747 748 out: 749 return ret; 750 } 751 EXPORT_SYMBOL_GPL(set_foreign_p2m_mapping); 752 753 int clear_foreign_p2m_mapping(struct gnttab_unmap_grant_ref *unmap_ops, 754 struct gnttab_unmap_grant_ref *kunmap_ops, 755 struct page **pages, unsigned int count) 756 { 757 int i, ret = 0; 758 759 if (xen_feature(XENFEAT_auto_translated_physmap)) 760 return 0; 761 762 for (i = 0; i < count; i++) { 763 unsigned long mfn = __pfn_to_mfn(page_to_pfn(pages[i])); 764 unsigned long pfn = page_to_pfn(pages[i]); 765 766 if (mfn == INVALID_P2M_ENTRY || !(mfn & FOREIGN_FRAME_BIT)) { 767 ret = -EINVAL; 768 goto out; 769 } 770 771 set_phys_to_machine(pfn, INVALID_P2M_ENTRY); 772 } 773 if (kunmap_ops) 774 ret = HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, 775 kunmap_ops, count); 776 out: 777 return ret; 778 } 779 EXPORT_SYMBOL_GPL(clear_foreign_p2m_mapping); 780 781 #ifdef CONFIG_XEN_DEBUG_FS 782 #include <linux/debugfs.h> 783 #include "debugfs.h" 784 static int p2m_dump_show(struct seq_file *m, void *v) 785 { 786 static const char * const type_name[] = { 787 [P2M_TYPE_IDENTITY] = "identity", 788 [P2M_TYPE_MISSING] = "missing", 789 [P2M_TYPE_PFN] = "pfn", 790 [P2M_TYPE_UNKNOWN] = "abnormal"}; 791 unsigned long pfn, first_pfn; 792 int type, prev_type; 793 794 prev_type = xen_p2m_elem_type(0); 795 first_pfn = 0; 796 797 for (pfn = 0; pfn < xen_p2m_size; pfn++) { 798 type = xen_p2m_elem_type(pfn); 799 if (type != prev_type) { 800 seq_printf(m, " [0x%lx->0x%lx] %s\n", first_pfn, pfn, 801 type_name[prev_type]); 802 prev_type = type; 803 first_pfn = pfn; 804 } 805 } 806 seq_printf(m, " [0x%lx->0x%lx] %s\n", first_pfn, pfn, 807 type_name[prev_type]); 808 return 0; 809 } 810 811 static int p2m_dump_open(struct inode *inode, struct file *filp) 812 { 813 return single_open(filp, p2m_dump_show, NULL); 814 } 815 816 static const struct file_operations p2m_dump_fops = { 817 .open = p2m_dump_open, 818 .read = seq_read, 819 .llseek = seq_lseek, 820 .release = single_release, 821 }; 822 823 static struct dentry *d_mmu_debug; 824 825 static int __init xen_p2m_debugfs(void) 826 { 827 struct dentry *d_xen = xen_init_debugfs(); 828 829 if (d_xen == NULL) 830 return -ENOMEM; 831 832 d_mmu_debug = debugfs_create_dir("mmu", d_xen); 833 834 debugfs_create_file("p2m", 0600, d_mmu_debug, NULL, &p2m_dump_fops); 835 return 0; 836 } 837 fs_initcall(xen_p2m_debugfs); 838 #endif /* CONFIG_XEN_DEBUG_FS */ 839