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 static inline unsigned p2m_top_index(unsigned long pfn) 116 { 117 BUG_ON(pfn >= MAX_P2M_PFN); 118 return pfn / (P2M_MID_PER_PAGE * P2M_PER_PAGE); 119 } 120 121 static inline unsigned p2m_mid_index(unsigned long pfn) 122 { 123 return (pfn / P2M_PER_PAGE) % P2M_MID_PER_PAGE; 124 } 125 126 static inline unsigned p2m_index(unsigned long pfn) 127 { 128 return pfn % P2M_PER_PAGE; 129 } 130 131 static void p2m_top_mfn_init(unsigned long *top) 132 { 133 unsigned i; 134 135 for (i = 0; i < P2M_TOP_PER_PAGE; i++) 136 top[i] = virt_to_mfn(p2m_mid_missing_mfn); 137 } 138 139 static void p2m_top_mfn_p_init(unsigned long **top) 140 { 141 unsigned i; 142 143 for (i = 0; i < P2M_TOP_PER_PAGE; i++) 144 top[i] = p2m_mid_missing_mfn; 145 } 146 147 static void p2m_mid_mfn_init(unsigned long *mid, unsigned long *leaf) 148 { 149 unsigned i; 150 151 for (i = 0; i < P2M_MID_PER_PAGE; i++) 152 mid[i] = virt_to_mfn(leaf); 153 } 154 155 static void p2m_init(unsigned long *p2m) 156 { 157 unsigned i; 158 159 for (i = 0; i < P2M_PER_PAGE; i++) 160 p2m[i] = INVALID_P2M_ENTRY; 161 } 162 163 static void p2m_init_identity(unsigned long *p2m, unsigned long pfn) 164 { 165 unsigned i; 166 167 for (i = 0; i < P2M_PER_PAGE; i++) 168 p2m[i] = IDENTITY_FRAME(pfn + i); 169 } 170 171 static void * __ref alloc_p2m_page(void) 172 { 173 if (unlikely(!slab_is_available())) 174 return alloc_bootmem_align(PAGE_SIZE, PAGE_SIZE); 175 176 return (void *)__get_free_page(GFP_KERNEL | __GFP_REPEAT); 177 } 178 179 static void __ref free_p2m_page(void *p) 180 { 181 if (unlikely(!slab_is_available())) { 182 free_bootmem((unsigned long)p, PAGE_SIZE); 183 return; 184 } 185 186 free_page((unsigned long)p); 187 } 188 189 /* 190 * Build the parallel p2m_top_mfn and p2m_mid_mfn structures 191 * 192 * This is called both at boot time, and after resuming from suspend: 193 * - At boot time we're called rather early, and must use alloc_bootmem*() 194 * to allocate memory. 195 * 196 * - After resume we're called from within stop_machine, but the mfn 197 * tree should already be completely allocated. 198 */ 199 void __ref xen_build_mfn_list_list(void) 200 { 201 unsigned long pfn, mfn; 202 pte_t *ptep; 203 unsigned int level, topidx, mididx; 204 unsigned long *mid_mfn_p; 205 206 if (xen_feature(XENFEAT_auto_translated_physmap) || 207 xen_start_info->flags & SIF_VIRT_P2M_4TOOLS) 208 return; 209 210 /* Pre-initialize p2m_top_mfn to be completely missing */ 211 if (p2m_top_mfn == NULL) { 212 p2m_mid_missing_mfn = alloc_p2m_page(); 213 p2m_mid_mfn_init(p2m_mid_missing_mfn, p2m_missing); 214 215 p2m_top_mfn_p = alloc_p2m_page(); 216 p2m_top_mfn_p_init(p2m_top_mfn_p); 217 218 p2m_top_mfn = alloc_p2m_page(); 219 p2m_top_mfn_init(p2m_top_mfn); 220 } else { 221 /* Reinitialise, mfn's all change after migration */ 222 p2m_mid_mfn_init(p2m_mid_missing_mfn, p2m_missing); 223 } 224 225 for (pfn = 0; pfn < xen_max_p2m_pfn && pfn < MAX_P2M_PFN; 226 pfn += P2M_PER_PAGE) { 227 topidx = p2m_top_index(pfn); 228 mididx = p2m_mid_index(pfn); 229 230 mid_mfn_p = p2m_top_mfn_p[topidx]; 231 ptep = lookup_address((unsigned long)(xen_p2m_addr + pfn), 232 &level); 233 BUG_ON(!ptep || level != PG_LEVEL_4K); 234 mfn = pte_mfn(*ptep); 235 ptep = (pte_t *)((unsigned long)ptep & ~(PAGE_SIZE - 1)); 236 237 /* Don't bother allocating any mfn mid levels if 238 * they're just missing, just update the stored mfn, 239 * since all could have changed over a migrate. 240 */ 241 if (ptep == p2m_missing_pte || ptep == p2m_identity_pte) { 242 BUG_ON(mididx); 243 BUG_ON(mid_mfn_p != p2m_mid_missing_mfn); 244 p2m_top_mfn[topidx] = virt_to_mfn(p2m_mid_missing_mfn); 245 pfn += (P2M_MID_PER_PAGE - 1) * P2M_PER_PAGE; 246 continue; 247 } 248 249 if (mid_mfn_p == p2m_mid_missing_mfn) { 250 mid_mfn_p = alloc_p2m_page(); 251 p2m_mid_mfn_init(mid_mfn_p, p2m_missing); 252 253 p2m_top_mfn_p[topidx] = mid_mfn_p; 254 } 255 256 p2m_top_mfn[topidx] = virt_to_mfn(mid_mfn_p); 257 mid_mfn_p[mididx] = mfn; 258 } 259 } 260 261 void xen_setup_mfn_list_list(void) 262 { 263 if (xen_feature(XENFEAT_auto_translated_physmap)) 264 return; 265 266 BUG_ON(HYPERVISOR_shared_info == &xen_dummy_shared_info); 267 268 if (xen_start_info->flags & SIF_VIRT_P2M_4TOOLS) 269 HYPERVISOR_shared_info->arch.pfn_to_mfn_frame_list_list = ~0UL; 270 else 271 HYPERVISOR_shared_info->arch.pfn_to_mfn_frame_list_list = 272 virt_to_mfn(p2m_top_mfn); 273 HYPERVISOR_shared_info->arch.max_pfn = xen_max_p2m_pfn; 274 HYPERVISOR_shared_info->arch.p2m_generation = 0; 275 HYPERVISOR_shared_info->arch.p2m_vaddr = (unsigned long)xen_p2m_addr; 276 HYPERVISOR_shared_info->arch.p2m_cr3 = 277 xen_pfn_to_cr3(virt_to_mfn(swapper_pg_dir)); 278 } 279 280 /* Set up p2m_top to point to the domain-builder provided p2m pages */ 281 void __init xen_build_dynamic_phys_to_machine(void) 282 { 283 unsigned long pfn; 284 285 if (xen_feature(XENFEAT_auto_translated_physmap)) 286 return; 287 288 xen_p2m_addr = (unsigned long *)xen_start_info->mfn_list; 289 xen_p2m_size = ALIGN(xen_start_info->nr_pages, P2M_PER_PAGE); 290 291 for (pfn = xen_start_info->nr_pages; pfn < xen_p2m_size; pfn++) 292 xen_p2m_addr[pfn] = INVALID_P2M_ENTRY; 293 294 xen_max_p2m_pfn = xen_p2m_size; 295 } 296 297 #define P2M_TYPE_IDENTITY 0 298 #define P2M_TYPE_MISSING 1 299 #define P2M_TYPE_PFN 2 300 #define P2M_TYPE_UNKNOWN 3 301 302 static int xen_p2m_elem_type(unsigned long pfn) 303 { 304 unsigned long mfn; 305 306 if (pfn >= xen_p2m_size) 307 return P2M_TYPE_IDENTITY; 308 309 mfn = xen_p2m_addr[pfn]; 310 311 if (mfn == INVALID_P2M_ENTRY) 312 return P2M_TYPE_MISSING; 313 314 if (mfn & IDENTITY_FRAME_BIT) 315 return P2M_TYPE_IDENTITY; 316 317 return P2M_TYPE_PFN; 318 } 319 320 static void __init xen_rebuild_p2m_list(unsigned long *p2m) 321 { 322 unsigned int i, chunk; 323 unsigned long pfn; 324 unsigned long *mfns; 325 pte_t *ptep; 326 pmd_t *pmdp; 327 int type; 328 329 p2m_missing = alloc_p2m_page(); 330 p2m_init(p2m_missing); 331 p2m_identity = alloc_p2m_page(); 332 p2m_init(p2m_identity); 333 334 p2m_missing_pte = alloc_p2m_page(); 335 paravirt_alloc_pte(&init_mm, __pa(p2m_missing_pte) >> PAGE_SHIFT); 336 p2m_identity_pte = alloc_p2m_page(); 337 paravirt_alloc_pte(&init_mm, __pa(p2m_identity_pte) >> PAGE_SHIFT); 338 for (i = 0; i < PTRS_PER_PTE; i++) { 339 set_pte(p2m_missing_pte + i, 340 pfn_pte(PFN_DOWN(__pa(p2m_missing)), PAGE_KERNEL_RO)); 341 set_pte(p2m_identity_pte + i, 342 pfn_pte(PFN_DOWN(__pa(p2m_identity)), PAGE_KERNEL_RO)); 343 } 344 345 for (pfn = 0; pfn < xen_max_p2m_pfn; pfn += chunk) { 346 /* 347 * Try to map missing/identity PMDs or p2m-pages if possible. 348 * We have to respect the structure of the mfn_list_list 349 * which will be built just afterwards. 350 * Chunk size to test is one p2m page if we are in the middle 351 * of a mfn_list_list mid page and the complete mid page area 352 * if we are at index 0 of the mid page. Please note that a 353 * mid page might cover more than one PMD, e.g. on 32 bit PAE 354 * kernels. 355 */ 356 chunk = (pfn & (P2M_PER_PAGE * P2M_MID_PER_PAGE - 1)) ? 357 P2M_PER_PAGE : P2M_PER_PAGE * P2M_MID_PER_PAGE; 358 359 type = xen_p2m_elem_type(pfn); 360 i = 0; 361 if (type != P2M_TYPE_PFN) 362 for (i = 1; i < chunk; i++) 363 if (xen_p2m_elem_type(pfn + i) != type) 364 break; 365 if (i < chunk) 366 /* Reset to minimal chunk size. */ 367 chunk = P2M_PER_PAGE; 368 369 if (type == P2M_TYPE_PFN || i < chunk) { 370 /* Use initial p2m page contents. */ 371 #ifdef CONFIG_X86_64 372 mfns = alloc_p2m_page(); 373 copy_page(mfns, xen_p2m_addr + pfn); 374 #else 375 mfns = xen_p2m_addr + pfn; 376 #endif 377 ptep = populate_extra_pte((unsigned long)(p2m + pfn)); 378 set_pte(ptep, 379 pfn_pte(PFN_DOWN(__pa(mfns)), PAGE_KERNEL)); 380 continue; 381 } 382 383 if (chunk == P2M_PER_PAGE) { 384 /* Map complete missing or identity p2m-page. */ 385 mfns = (type == P2M_TYPE_MISSING) ? 386 p2m_missing : p2m_identity; 387 ptep = populate_extra_pte((unsigned long)(p2m + pfn)); 388 set_pte(ptep, 389 pfn_pte(PFN_DOWN(__pa(mfns)), PAGE_KERNEL_RO)); 390 continue; 391 } 392 393 /* Complete missing or identity PMD(s) can be mapped. */ 394 ptep = (type == P2M_TYPE_MISSING) ? 395 p2m_missing_pte : p2m_identity_pte; 396 for (i = 0; i < PMDS_PER_MID_PAGE; i++) { 397 pmdp = populate_extra_pmd( 398 (unsigned long)(p2m + pfn) + i * PMD_SIZE); 399 set_pmd(pmdp, __pmd(__pa(ptep) | _KERNPG_TABLE)); 400 } 401 } 402 } 403 404 void __init xen_vmalloc_p2m_tree(void) 405 { 406 static struct vm_struct vm; 407 unsigned long p2m_limit; 408 409 p2m_limit = (phys_addr_t)P2M_LIMIT * 1024 * 1024 * 1024 / PAGE_SIZE; 410 vm.flags = VM_ALLOC; 411 vm.size = ALIGN(sizeof(unsigned long) * max(xen_max_p2m_pfn, p2m_limit), 412 PMD_SIZE * PMDS_PER_MID_PAGE); 413 vm_area_register_early(&vm, PMD_SIZE * PMDS_PER_MID_PAGE); 414 pr_notice("p2m virtual area at %p, size is %lx\n", vm.addr, vm.size); 415 416 xen_max_p2m_pfn = vm.size / sizeof(unsigned long); 417 418 xen_rebuild_p2m_list(vm.addr); 419 420 xen_p2m_addr = vm.addr; 421 xen_p2m_size = xen_max_p2m_pfn; 422 423 xen_inv_extra_mem(); 424 } 425 426 unsigned long get_phys_to_machine(unsigned long pfn) 427 { 428 pte_t *ptep; 429 unsigned int level; 430 431 if (unlikely(pfn >= xen_p2m_size)) { 432 if (pfn < xen_max_p2m_pfn) 433 return xen_chk_extra_mem(pfn); 434 435 return IDENTITY_FRAME(pfn); 436 } 437 438 ptep = lookup_address((unsigned long)(xen_p2m_addr + pfn), &level); 439 BUG_ON(!ptep || level != PG_LEVEL_4K); 440 441 /* 442 * The INVALID_P2M_ENTRY is filled in both p2m_*identity 443 * and in p2m_*missing, so returning the INVALID_P2M_ENTRY 444 * would be wrong. 445 */ 446 if (pte_pfn(*ptep) == PFN_DOWN(__pa(p2m_identity))) 447 return IDENTITY_FRAME(pfn); 448 449 return xen_p2m_addr[pfn]; 450 } 451 EXPORT_SYMBOL_GPL(get_phys_to_machine); 452 453 /* 454 * Allocate new pmd(s). It is checked whether the old pmd is still in place. 455 * If not, nothing is changed. This is okay as the only reason for allocating 456 * a new pmd is to replace p2m_missing_pte or p2m_identity_pte by a individual 457 * pmd. In case of PAE/x86-32 there are multiple pmds to allocate! 458 */ 459 static pte_t *alloc_p2m_pmd(unsigned long addr, pte_t *pte_pg) 460 { 461 pte_t *ptechk; 462 pte_t *pte_newpg[PMDS_PER_MID_PAGE]; 463 pmd_t *pmdp; 464 unsigned int level; 465 unsigned long flags; 466 unsigned long vaddr; 467 int i; 468 469 /* Do all allocations first to bail out in error case. */ 470 for (i = 0; i < PMDS_PER_MID_PAGE; i++) { 471 pte_newpg[i] = alloc_p2m_page(); 472 if (!pte_newpg[i]) { 473 for (i--; i >= 0; i--) 474 free_p2m_page(pte_newpg[i]); 475 476 return NULL; 477 } 478 } 479 480 vaddr = addr & ~(PMD_SIZE * PMDS_PER_MID_PAGE - 1); 481 482 for (i = 0; i < PMDS_PER_MID_PAGE; i++) { 483 copy_page(pte_newpg[i], pte_pg); 484 paravirt_alloc_pte(&init_mm, __pa(pte_newpg[i]) >> PAGE_SHIFT); 485 486 pmdp = lookup_pmd_address(vaddr); 487 BUG_ON(!pmdp); 488 489 spin_lock_irqsave(&p2m_update_lock, flags); 490 491 ptechk = lookup_address(vaddr, &level); 492 if (ptechk == pte_pg) { 493 HYPERVISOR_shared_info->arch.p2m_generation++; 494 wmb(); /* Tools are synchronizing via p2m_generation. */ 495 set_pmd(pmdp, 496 __pmd(__pa(pte_newpg[i]) | _KERNPG_TABLE)); 497 wmb(); /* Tools are synchronizing via p2m_generation. */ 498 HYPERVISOR_shared_info->arch.p2m_generation++; 499 pte_newpg[i] = NULL; 500 } 501 502 spin_unlock_irqrestore(&p2m_update_lock, flags); 503 504 if (pte_newpg[i]) { 505 paravirt_release_pte(__pa(pte_newpg[i]) >> PAGE_SHIFT); 506 free_p2m_page(pte_newpg[i]); 507 } 508 509 vaddr += PMD_SIZE; 510 } 511 512 return lookup_address(addr, &level); 513 } 514 515 /* 516 * Fully allocate the p2m structure for a given pfn. We need to check 517 * that both the top and mid levels are allocated, and make sure the 518 * parallel mfn tree is kept in sync. We may race with other cpus, so 519 * the new pages are installed with cmpxchg; if we lose the race then 520 * simply free the page we allocated and use the one that's there. 521 */ 522 static bool alloc_p2m(unsigned long pfn) 523 { 524 unsigned topidx; 525 unsigned long *top_mfn_p, *mid_mfn; 526 pte_t *ptep, *pte_pg; 527 unsigned int level; 528 unsigned long flags; 529 unsigned long addr = (unsigned long)(xen_p2m_addr + pfn); 530 unsigned long p2m_pfn; 531 532 ptep = lookup_address(addr, &level); 533 BUG_ON(!ptep || level != PG_LEVEL_4K); 534 pte_pg = (pte_t *)((unsigned long)ptep & ~(PAGE_SIZE - 1)); 535 536 if (pte_pg == p2m_missing_pte || pte_pg == p2m_identity_pte) { 537 /* PMD level is missing, allocate a new one */ 538 ptep = alloc_p2m_pmd(addr, pte_pg); 539 if (!ptep) 540 return false; 541 } 542 543 if (p2m_top_mfn && pfn < MAX_P2M_PFN) { 544 topidx = p2m_top_index(pfn); 545 top_mfn_p = &p2m_top_mfn[topidx]; 546 mid_mfn = ACCESS_ONCE(p2m_top_mfn_p[topidx]); 547 548 BUG_ON(virt_to_mfn(mid_mfn) != *top_mfn_p); 549 550 if (mid_mfn == p2m_mid_missing_mfn) { 551 /* Separately check the mid mfn level */ 552 unsigned long missing_mfn; 553 unsigned long mid_mfn_mfn; 554 unsigned long old_mfn; 555 556 mid_mfn = alloc_p2m_page(); 557 if (!mid_mfn) 558 return false; 559 560 p2m_mid_mfn_init(mid_mfn, p2m_missing); 561 562 missing_mfn = virt_to_mfn(p2m_mid_missing_mfn); 563 mid_mfn_mfn = virt_to_mfn(mid_mfn); 564 old_mfn = cmpxchg(top_mfn_p, missing_mfn, mid_mfn_mfn); 565 if (old_mfn != missing_mfn) { 566 free_p2m_page(mid_mfn); 567 mid_mfn = mfn_to_virt(old_mfn); 568 } else { 569 p2m_top_mfn_p[topidx] = mid_mfn; 570 } 571 } 572 } else { 573 mid_mfn = NULL; 574 } 575 576 p2m_pfn = pte_pfn(READ_ONCE(*ptep)); 577 if (p2m_pfn == PFN_DOWN(__pa(p2m_identity)) || 578 p2m_pfn == PFN_DOWN(__pa(p2m_missing))) { 579 /* p2m leaf page is missing */ 580 unsigned long *p2m; 581 582 p2m = alloc_p2m_page(); 583 if (!p2m) 584 return false; 585 586 if (p2m_pfn == PFN_DOWN(__pa(p2m_missing))) 587 p2m_init(p2m); 588 else 589 p2m_init_identity(p2m, pfn & ~(P2M_PER_PAGE - 1)); 590 591 spin_lock_irqsave(&p2m_update_lock, flags); 592 593 if (pte_pfn(*ptep) == p2m_pfn) { 594 HYPERVISOR_shared_info->arch.p2m_generation++; 595 wmb(); /* Tools are synchronizing via p2m_generation. */ 596 set_pte(ptep, 597 pfn_pte(PFN_DOWN(__pa(p2m)), PAGE_KERNEL)); 598 wmb(); /* Tools are synchronizing via p2m_generation. */ 599 HYPERVISOR_shared_info->arch.p2m_generation++; 600 if (mid_mfn) 601 mid_mfn[p2m_mid_index(pfn)] = virt_to_mfn(p2m); 602 p2m = NULL; 603 } 604 605 spin_unlock_irqrestore(&p2m_update_lock, flags); 606 607 if (p2m) 608 free_p2m_page(p2m); 609 } 610 611 return true; 612 } 613 614 unsigned long __init set_phys_range_identity(unsigned long pfn_s, 615 unsigned long pfn_e) 616 { 617 unsigned long pfn; 618 619 if (unlikely(pfn_s >= xen_p2m_size)) 620 return 0; 621 622 if (unlikely(xen_feature(XENFEAT_auto_translated_physmap))) 623 return pfn_e - pfn_s; 624 625 if (pfn_s > pfn_e) 626 return 0; 627 628 if (pfn_e > xen_p2m_size) 629 pfn_e = xen_p2m_size; 630 631 for (pfn = pfn_s; pfn < pfn_e; pfn++) 632 xen_p2m_addr[pfn] = IDENTITY_FRAME(pfn); 633 634 return pfn - pfn_s; 635 } 636 637 bool __set_phys_to_machine(unsigned long pfn, unsigned long mfn) 638 { 639 pte_t *ptep; 640 unsigned int level; 641 642 /* don't track P2M changes in autotranslate guests */ 643 if (unlikely(xen_feature(XENFEAT_auto_translated_physmap))) 644 return true; 645 646 if (unlikely(pfn >= xen_p2m_size)) { 647 BUG_ON(mfn != INVALID_P2M_ENTRY); 648 return true; 649 } 650 651 /* 652 * The interface requires atomic updates on p2m elements. 653 * xen_safe_write_ulong() is using __put_user which does an atomic 654 * store via asm(). 655 */ 656 if (likely(!xen_safe_write_ulong(xen_p2m_addr + pfn, mfn))) 657 return true; 658 659 ptep = lookup_address((unsigned long)(xen_p2m_addr + pfn), &level); 660 BUG_ON(!ptep || level != PG_LEVEL_4K); 661 662 if (pte_pfn(*ptep) == PFN_DOWN(__pa(p2m_missing))) 663 return mfn == INVALID_P2M_ENTRY; 664 665 if (pte_pfn(*ptep) == PFN_DOWN(__pa(p2m_identity))) 666 return mfn == IDENTITY_FRAME(pfn); 667 668 return false; 669 } 670 671 bool set_phys_to_machine(unsigned long pfn, unsigned long mfn) 672 { 673 if (unlikely(!__set_phys_to_machine(pfn, mfn))) { 674 if (!alloc_p2m(pfn)) 675 return false; 676 677 return __set_phys_to_machine(pfn, mfn); 678 } 679 680 return true; 681 } 682 683 int set_foreign_p2m_mapping(struct gnttab_map_grant_ref *map_ops, 684 struct gnttab_map_grant_ref *kmap_ops, 685 struct page **pages, unsigned int count) 686 { 687 int i, ret = 0; 688 pte_t *pte; 689 690 if (xen_feature(XENFEAT_auto_translated_physmap)) 691 return 0; 692 693 if (kmap_ops) { 694 ret = HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, 695 kmap_ops, count); 696 if (ret) 697 goto out; 698 } 699 700 for (i = 0; i < count; i++) { 701 unsigned long mfn, pfn; 702 703 /* Do not add to override if the map failed. */ 704 if (map_ops[i].status) 705 continue; 706 707 if (map_ops[i].flags & GNTMAP_contains_pte) { 708 pte = (pte_t *)(mfn_to_virt(PFN_DOWN(map_ops[i].host_addr)) + 709 (map_ops[i].host_addr & ~PAGE_MASK)); 710 mfn = pte_mfn(*pte); 711 } else { 712 mfn = PFN_DOWN(map_ops[i].dev_bus_addr); 713 } 714 pfn = page_to_pfn(pages[i]); 715 716 WARN(pfn_to_mfn(pfn) != INVALID_P2M_ENTRY, "page must be ballooned"); 717 718 if (unlikely(!set_phys_to_machine(pfn, FOREIGN_FRAME(mfn)))) { 719 ret = -ENOMEM; 720 goto out; 721 } 722 } 723 724 out: 725 return ret; 726 } 727 EXPORT_SYMBOL_GPL(set_foreign_p2m_mapping); 728 729 int clear_foreign_p2m_mapping(struct gnttab_unmap_grant_ref *unmap_ops, 730 struct gnttab_unmap_grant_ref *kunmap_ops, 731 struct page **pages, unsigned int count) 732 { 733 int i, ret = 0; 734 735 if (xen_feature(XENFEAT_auto_translated_physmap)) 736 return 0; 737 738 for (i = 0; i < count; i++) { 739 unsigned long mfn = __pfn_to_mfn(page_to_pfn(pages[i])); 740 unsigned long pfn = page_to_pfn(pages[i]); 741 742 if (mfn == INVALID_P2M_ENTRY || !(mfn & FOREIGN_FRAME_BIT)) { 743 ret = -EINVAL; 744 goto out; 745 } 746 747 set_phys_to_machine(pfn, INVALID_P2M_ENTRY); 748 } 749 if (kunmap_ops) 750 ret = HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, 751 kunmap_ops, count); 752 out: 753 return ret; 754 } 755 EXPORT_SYMBOL_GPL(clear_foreign_p2m_mapping); 756 757 #ifdef CONFIG_XEN_DEBUG_FS 758 #include <linux/debugfs.h> 759 #include "debugfs.h" 760 static int p2m_dump_show(struct seq_file *m, void *v) 761 { 762 static const char * const type_name[] = { 763 [P2M_TYPE_IDENTITY] = "identity", 764 [P2M_TYPE_MISSING] = "missing", 765 [P2M_TYPE_PFN] = "pfn", 766 [P2M_TYPE_UNKNOWN] = "abnormal"}; 767 unsigned long pfn, first_pfn; 768 int type, prev_type; 769 770 prev_type = xen_p2m_elem_type(0); 771 first_pfn = 0; 772 773 for (pfn = 0; pfn < xen_p2m_size; pfn++) { 774 type = xen_p2m_elem_type(pfn); 775 if (type != prev_type) { 776 seq_printf(m, " [0x%lx->0x%lx] %s\n", first_pfn, pfn, 777 type_name[prev_type]); 778 prev_type = type; 779 first_pfn = pfn; 780 } 781 } 782 seq_printf(m, " [0x%lx->0x%lx] %s\n", first_pfn, pfn, 783 type_name[prev_type]); 784 return 0; 785 } 786 787 static int p2m_dump_open(struct inode *inode, struct file *filp) 788 { 789 return single_open(filp, p2m_dump_show, NULL); 790 } 791 792 static const struct file_operations p2m_dump_fops = { 793 .open = p2m_dump_open, 794 .read = seq_read, 795 .llseek = seq_lseek, 796 .release = single_release, 797 }; 798 799 static struct dentry *d_mmu_debug; 800 801 static int __init xen_p2m_debugfs(void) 802 { 803 struct dentry *d_xen = xen_init_debugfs(); 804 805 if (d_xen == NULL) 806 return -ENOMEM; 807 808 d_mmu_debug = debugfs_create_dir("mmu", d_xen); 809 810 debugfs_create_file("p2m", 0600, d_mmu_debug, NULL, &p2m_dump_fops); 811 return 0; 812 } 813 fs_initcall(xen_p2m_debugfs); 814 #endif /* CONFIG_XEN_DEBUG_FS */ 815