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