1 // SPDX-License-Identifier: GPL-2.0 2 3 /* 4 * Xen leaves the responsibility for maintaining p2m mappings to the 5 * guests themselves, but it must also access and update the p2m array 6 * during suspend/resume when all the pages are reallocated. 7 * 8 * The logical flat p2m table is mapped to a linear kernel memory area. 9 * For accesses by Xen a three-level tree linked via mfns only is set up to 10 * allow the address space to be sparse. 11 * 12 * Xen 13 * | 14 * p2m_top_mfn 15 * / \ 16 * p2m_mid_mfn p2m_mid_mfn 17 * / / 18 * p2m p2m p2m ... 19 * 20 * The p2m_mid_mfn pages are mapped by p2m_top_mfn_p. 21 * 22 * The p2m_top_mfn level is limited to 1 page, so the maximum representable 23 * pseudo-physical address space is: 24 * P2M_TOP_PER_PAGE * P2M_MID_PER_PAGE * P2M_PER_PAGE pages 25 * 26 * P2M_PER_PAGE depends on the architecture, as a mfn is always 27 * unsigned long (8 bytes on 64-bit, 4 bytes on 32), leading to 28 * 512 and 1024 entries respectively. 29 * 30 * In short, these structures contain the Machine Frame Number (MFN) of the PFN. 31 * 32 * However not all entries are filled with MFNs. Specifically for all other 33 * leaf entries, or for the top root, or middle one, for which there is a void 34 * entry, we assume it is "missing". So (for example) 35 * pfn_to_mfn(0x90909090)=INVALID_P2M_ENTRY. 36 * We have a dedicated page p2m_missing with all entries being 37 * INVALID_P2M_ENTRY. This page may be referenced multiple times in the p2m 38 * list/tree in case there are multiple areas with P2M_PER_PAGE invalid pfns. 39 * 40 * We also have the possibility of setting 1-1 mappings on certain regions, so 41 * that: 42 * pfn_to_mfn(0xc0000)=0xc0000 43 * 44 * The benefit of this is, that we can assume for non-RAM regions (think 45 * PCI BARs, or ACPI spaces), we can create mappings easily because we 46 * get the PFN value to match the MFN. 47 * 48 * For this to work efficiently we have one new page p2m_identity. All entries 49 * in p2m_identity are set to INVALID_P2M_ENTRY type (Xen toolstack only 50 * recognizes that and MFNs, no other fancy value). 51 * 52 * On lookup we spot that the entry points to p2m_identity and return the 53 * identity value instead of dereferencing and returning INVALID_P2M_ENTRY. 54 * If the entry points to an allocated page, we just proceed as before and 55 * return the PFN. If the PFN has IDENTITY_FRAME_BIT set we unmask that in 56 * appropriate functions (pfn_to_mfn). 57 * 58 * The reason for having the IDENTITY_FRAME_BIT instead of just returning the 59 * PFN is that we could find ourselves where pfn_to_mfn(pfn)==pfn for a 60 * non-identity pfn. To protect ourselves against we elect to set (and get) the 61 * IDENTITY_FRAME_BIT on all identity mapped PFNs. 62 */ 63 64 #include <linux/init.h> 65 #include <linux/export.h> 66 #include <linux/list.h> 67 #include <linux/hash.h> 68 #include <linux/sched.h> 69 #include <linux/seq_file.h> 70 #include <linux/memblock.h> 71 #include <linux/slab.h> 72 #include <linux/vmalloc.h> 73 74 #include <asm/cache.h> 75 #include <asm/setup.h> 76 #include <linux/uaccess.h> 77 78 #include <asm/xen/page.h> 79 #include <asm/xen/hypercall.h> 80 #include <asm/xen/hypervisor.h> 81 #include <xen/balloon.h> 82 #include <xen/grant_table.h> 83 84 #include "multicalls.h" 85 #include "xen-ops.h" 86 87 #define P2M_MID_PER_PAGE (PAGE_SIZE / sizeof(unsigned long *)) 88 #define P2M_TOP_PER_PAGE (PAGE_SIZE / sizeof(unsigned long **)) 89 90 #define MAX_P2M_PFN (P2M_TOP_PER_PAGE * P2M_MID_PER_PAGE * P2M_PER_PAGE) 91 92 #define PMDS_PER_MID_PAGE (P2M_MID_PER_PAGE / PTRS_PER_PTE) 93 94 unsigned long *xen_p2m_addr __read_mostly; 95 EXPORT_SYMBOL_GPL(xen_p2m_addr); 96 unsigned long xen_p2m_size __read_mostly; 97 EXPORT_SYMBOL_GPL(xen_p2m_size); 98 unsigned long xen_max_p2m_pfn __read_mostly; 99 EXPORT_SYMBOL_GPL(xen_max_p2m_pfn); 100 101 #ifdef CONFIG_XEN_BALLOON_MEMORY_HOTPLUG_LIMIT 102 #define P2M_LIMIT CONFIG_XEN_BALLOON_MEMORY_HOTPLUG_LIMIT 103 #else 104 #define P2M_LIMIT 0 105 #endif 106 107 static DEFINE_SPINLOCK(p2m_update_lock); 108 109 static unsigned long *p2m_mid_missing_mfn; 110 static unsigned long *p2m_top_mfn; 111 static unsigned long **p2m_top_mfn_p; 112 static unsigned long *p2m_missing; 113 static unsigned long *p2m_identity; 114 static pte_t *p2m_missing_pte; 115 static pte_t *p2m_identity_pte; 116 117 /* 118 * Hint at last populated PFN. 119 * 120 * Used to set HYPERVISOR_shared_info->arch.max_pfn so the toolstack 121 * can avoid scanning the whole P2M (which may be sized to account for 122 * hotplugged memory). 123 */ 124 static unsigned long xen_p2m_last_pfn; 125 126 static inline unsigned p2m_top_index(unsigned long pfn) 127 { 128 BUG_ON(pfn >= MAX_P2M_PFN); 129 return pfn / (P2M_MID_PER_PAGE * P2M_PER_PAGE); 130 } 131 132 static inline unsigned p2m_mid_index(unsigned long pfn) 133 { 134 return (pfn / P2M_PER_PAGE) % P2M_MID_PER_PAGE; 135 } 136 137 static inline unsigned p2m_index(unsigned long pfn) 138 { 139 return pfn % P2M_PER_PAGE; 140 } 141 142 static void p2m_top_mfn_init(unsigned long *top) 143 { 144 unsigned i; 145 146 for (i = 0; i < P2M_TOP_PER_PAGE; i++) 147 top[i] = virt_to_mfn(p2m_mid_missing_mfn); 148 } 149 150 static void p2m_top_mfn_p_init(unsigned long **top) 151 { 152 unsigned i; 153 154 for (i = 0; i < P2M_TOP_PER_PAGE; i++) 155 top[i] = p2m_mid_missing_mfn; 156 } 157 158 static void p2m_mid_mfn_init(unsigned long *mid, unsigned long *leaf) 159 { 160 unsigned i; 161 162 for (i = 0; i < P2M_MID_PER_PAGE; i++) 163 mid[i] = virt_to_mfn(leaf); 164 } 165 166 static void p2m_init(unsigned long *p2m) 167 { 168 unsigned i; 169 170 for (i = 0; i < P2M_PER_PAGE; i++) 171 p2m[i] = INVALID_P2M_ENTRY; 172 } 173 174 static void p2m_init_identity(unsigned long *p2m, unsigned long pfn) 175 { 176 unsigned i; 177 178 for (i = 0; i < P2M_PER_PAGE; i++) 179 p2m[i] = IDENTITY_FRAME(pfn + i); 180 } 181 182 static void * __ref alloc_p2m_page(void) 183 { 184 if (unlikely(!slab_is_available())) 185 return memblock_alloc(PAGE_SIZE, PAGE_SIZE); 186 187 return (void *)__get_free_page(GFP_KERNEL); 188 } 189 190 static void __ref free_p2m_page(void *p) 191 { 192 if (unlikely(!slab_is_available())) { 193 memblock_free((unsigned long)p, PAGE_SIZE); 194 return; 195 } 196 197 free_page((unsigned long)p); 198 } 199 200 /* 201 * Build the parallel p2m_top_mfn and p2m_mid_mfn structures 202 * 203 * This is called both at boot time, and after resuming from suspend: 204 * - At boot time we're called rather early, and must use alloc_bootmem*() 205 * to allocate memory. 206 * 207 * - After resume we're called from within stop_machine, but the mfn 208 * tree should already be completely allocated. 209 */ 210 void __ref xen_build_mfn_list_list(void) 211 { 212 unsigned long pfn, mfn; 213 pte_t *ptep; 214 unsigned int level, topidx, mididx; 215 unsigned long *mid_mfn_p; 216 217 if (xen_start_info->flags & SIF_VIRT_P2M_4TOOLS) 218 return; 219 220 /* Pre-initialize p2m_top_mfn to be completely missing */ 221 if (p2m_top_mfn == NULL) { 222 p2m_mid_missing_mfn = alloc_p2m_page(); 223 p2m_mid_mfn_init(p2m_mid_missing_mfn, p2m_missing); 224 225 p2m_top_mfn_p = alloc_p2m_page(); 226 p2m_top_mfn_p_init(p2m_top_mfn_p); 227 228 p2m_top_mfn = alloc_p2m_page(); 229 p2m_top_mfn_init(p2m_top_mfn); 230 } else { 231 /* Reinitialise, mfn's all change after migration */ 232 p2m_mid_mfn_init(p2m_mid_missing_mfn, p2m_missing); 233 } 234 235 for (pfn = 0; pfn < xen_max_p2m_pfn && pfn < MAX_P2M_PFN; 236 pfn += P2M_PER_PAGE) { 237 topidx = p2m_top_index(pfn); 238 mididx = p2m_mid_index(pfn); 239 240 mid_mfn_p = p2m_top_mfn_p[topidx]; 241 ptep = lookup_address((unsigned long)(xen_p2m_addr + pfn), 242 &level); 243 BUG_ON(!ptep || level != PG_LEVEL_4K); 244 mfn = pte_mfn(*ptep); 245 ptep = (pte_t *)((unsigned long)ptep & ~(PAGE_SIZE - 1)); 246 247 /* Don't bother allocating any mfn mid levels if 248 * they're just missing, just update the stored mfn, 249 * since all could have changed over a migrate. 250 */ 251 if (ptep == p2m_missing_pte || ptep == p2m_identity_pte) { 252 BUG_ON(mididx); 253 BUG_ON(mid_mfn_p != p2m_mid_missing_mfn); 254 p2m_top_mfn[topidx] = virt_to_mfn(p2m_mid_missing_mfn); 255 pfn += (P2M_MID_PER_PAGE - 1) * P2M_PER_PAGE; 256 continue; 257 } 258 259 if (mid_mfn_p == p2m_mid_missing_mfn) { 260 mid_mfn_p = alloc_p2m_page(); 261 p2m_mid_mfn_init(mid_mfn_p, p2m_missing); 262 263 p2m_top_mfn_p[topidx] = mid_mfn_p; 264 } 265 266 p2m_top_mfn[topidx] = virt_to_mfn(mid_mfn_p); 267 mid_mfn_p[mididx] = mfn; 268 } 269 } 270 271 void xen_setup_mfn_list_list(void) 272 { 273 BUG_ON(HYPERVISOR_shared_info == &xen_dummy_shared_info); 274 275 if (xen_start_info->flags & SIF_VIRT_P2M_4TOOLS) 276 HYPERVISOR_shared_info->arch.pfn_to_mfn_frame_list_list = ~0UL; 277 else 278 HYPERVISOR_shared_info->arch.pfn_to_mfn_frame_list_list = 279 virt_to_mfn(p2m_top_mfn); 280 HYPERVISOR_shared_info->arch.max_pfn = xen_p2m_last_pfn; 281 HYPERVISOR_shared_info->arch.p2m_generation = 0; 282 HYPERVISOR_shared_info->arch.p2m_vaddr = (unsigned long)xen_p2m_addr; 283 HYPERVISOR_shared_info->arch.p2m_cr3 = 284 xen_pfn_to_cr3(virt_to_mfn(swapper_pg_dir)); 285 } 286 287 /* Set up p2m_top to point to the domain-builder provided p2m pages */ 288 void __init xen_build_dynamic_phys_to_machine(void) 289 { 290 unsigned long pfn; 291 292 xen_p2m_addr = (unsigned long *)xen_start_info->mfn_list; 293 xen_p2m_size = ALIGN(xen_start_info->nr_pages, P2M_PER_PAGE); 294 295 for (pfn = xen_start_info->nr_pages; pfn < xen_p2m_size; pfn++) 296 xen_p2m_addr[pfn] = INVALID_P2M_ENTRY; 297 298 xen_max_p2m_pfn = xen_p2m_size; 299 } 300 301 #define P2M_TYPE_IDENTITY 0 302 #define P2M_TYPE_MISSING 1 303 #define P2M_TYPE_PFN 2 304 #define P2M_TYPE_UNKNOWN 3 305 306 static int xen_p2m_elem_type(unsigned long pfn) 307 { 308 unsigned long mfn; 309 310 if (pfn >= xen_p2m_size) 311 return P2M_TYPE_IDENTITY; 312 313 mfn = xen_p2m_addr[pfn]; 314 315 if (mfn == INVALID_P2M_ENTRY) 316 return P2M_TYPE_MISSING; 317 318 if (mfn & IDENTITY_FRAME_BIT) 319 return P2M_TYPE_IDENTITY; 320 321 return P2M_TYPE_PFN; 322 } 323 324 static void __init xen_rebuild_p2m_list(unsigned long *p2m) 325 { 326 unsigned int i, chunk; 327 unsigned long pfn; 328 unsigned long *mfns; 329 pte_t *ptep; 330 pmd_t *pmdp; 331 int type; 332 333 p2m_missing = alloc_p2m_page(); 334 p2m_init(p2m_missing); 335 p2m_identity = alloc_p2m_page(); 336 p2m_init(p2m_identity); 337 338 p2m_missing_pte = alloc_p2m_page(); 339 paravirt_alloc_pte(&init_mm, __pa(p2m_missing_pte) >> PAGE_SHIFT); 340 p2m_identity_pte = alloc_p2m_page(); 341 paravirt_alloc_pte(&init_mm, __pa(p2m_identity_pte) >> PAGE_SHIFT); 342 for (i = 0; i < PTRS_PER_PTE; i++) { 343 set_pte(p2m_missing_pte + i, 344 pfn_pte(PFN_DOWN(__pa(p2m_missing)), PAGE_KERNEL_RO)); 345 set_pte(p2m_identity_pte + i, 346 pfn_pte(PFN_DOWN(__pa(p2m_identity)), PAGE_KERNEL_RO)); 347 } 348 349 for (pfn = 0; pfn < xen_max_p2m_pfn; pfn += chunk) { 350 /* 351 * Try to map missing/identity PMDs or p2m-pages if possible. 352 * We have to respect the structure of the mfn_list_list 353 * which will be built just afterwards. 354 * Chunk size to test is one p2m page if we are in the middle 355 * of a mfn_list_list mid page and the complete mid page area 356 * if we are at index 0 of the mid page. Please note that a 357 * mid page might cover more than one PMD, e.g. on 32 bit PAE 358 * kernels. 359 */ 360 chunk = (pfn & (P2M_PER_PAGE * P2M_MID_PER_PAGE - 1)) ? 361 P2M_PER_PAGE : P2M_PER_PAGE * P2M_MID_PER_PAGE; 362 363 type = xen_p2m_elem_type(pfn); 364 i = 0; 365 if (type != P2M_TYPE_PFN) 366 for (i = 1; i < chunk; i++) 367 if (xen_p2m_elem_type(pfn + i) != type) 368 break; 369 if (i < chunk) 370 /* Reset to minimal chunk size. */ 371 chunk = P2M_PER_PAGE; 372 373 if (type == P2M_TYPE_PFN || i < chunk) { 374 /* Use initial p2m page contents. */ 375 #ifdef CONFIG_X86_64 376 mfns = alloc_p2m_page(); 377 copy_page(mfns, xen_p2m_addr + pfn); 378 #else 379 mfns = xen_p2m_addr + pfn; 380 #endif 381 ptep = populate_extra_pte((unsigned long)(p2m + pfn)); 382 set_pte(ptep, 383 pfn_pte(PFN_DOWN(__pa(mfns)), PAGE_KERNEL)); 384 continue; 385 } 386 387 if (chunk == P2M_PER_PAGE) { 388 /* Map complete missing or identity p2m-page. */ 389 mfns = (type == P2M_TYPE_MISSING) ? 390 p2m_missing : p2m_identity; 391 ptep = populate_extra_pte((unsigned long)(p2m + pfn)); 392 set_pte(ptep, 393 pfn_pte(PFN_DOWN(__pa(mfns)), PAGE_KERNEL_RO)); 394 continue; 395 } 396 397 /* Complete missing or identity PMD(s) can be mapped. */ 398 ptep = (type == P2M_TYPE_MISSING) ? 399 p2m_missing_pte : p2m_identity_pte; 400 for (i = 0; i < PMDS_PER_MID_PAGE; i++) { 401 pmdp = populate_extra_pmd( 402 (unsigned long)(p2m + pfn) + i * PMD_SIZE); 403 set_pmd(pmdp, __pmd(__pa(ptep) | _KERNPG_TABLE)); 404 } 405 } 406 } 407 408 void __init xen_vmalloc_p2m_tree(void) 409 { 410 static struct vm_struct vm; 411 unsigned long p2m_limit; 412 413 xen_p2m_last_pfn = xen_max_p2m_pfn; 414 415 p2m_limit = (phys_addr_t)P2M_LIMIT * 1024 * 1024 * 1024 / PAGE_SIZE; 416 vm.flags = VM_ALLOC; 417 vm.size = ALIGN(sizeof(unsigned long) * max(xen_max_p2m_pfn, p2m_limit), 418 PMD_SIZE * PMDS_PER_MID_PAGE); 419 vm_area_register_early(&vm, PMD_SIZE * PMDS_PER_MID_PAGE); 420 pr_notice("p2m virtual area at %p, size is %lx\n", vm.addr, vm.size); 421 422 xen_max_p2m_pfn = vm.size / sizeof(unsigned long); 423 424 xen_rebuild_p2m_list(vm.addr); 425 426 xen_p2m_addr = vm.addr; 427 xen_p2m_size = xen_max_p2m_pfn; 428 429 xen_inv_extra_mem(); 430 } 431 432 unsigned long get_phys_to_machine(unsigned long pfn) 433 { 434 pte_t *ptep; 435 unsigned int level; 436 437 if (unlikely(pfn >= xen_p2m_size)) { 438 if (pfn < xen_max_p2m_pfn) 439 return xen_chk_extra_mem(pfn); 440 441 return IDENTITY_FRAME(pfn); 442 } 443 444 ptep = lookup_address((unsigned long)(xen_p2m_addr + pfn), &level); 445 BUG_ON(!ptep || level != PG_LEVEL_4K); 446 447 /* 448 * The INVALID_P2M_ENTRY is filled in both p2m_*identity 449 * and in p2m_*missing, so returning the INVALID_P2M_ENTRY 450 * would be wrong. 451 */ 452 if (pte_pfn(*ptep) == PFN_DOWN(__pa(p2m_identity))) 453 return IDENTITY_FRAME(pfn); 454 455 return xen_p2m_addr[pfn]; 456 } 457 EXPORT_SYMBOL_GPL(get_phys_to_machine); 458 459 /* 460 * Allocate new pmd(s). It is checked whether the old pmd is still in place. 461 * If not, nothing is changed. This is okay as the only reason for allocating 462 * a new pmd is to replace p2m_missing_pte or p2m_identity_pte by a individual 463 * pmd. In case of PAE/x86-32 there are multiple pmds to allocate! 464 */ 465 static pte_t *alloc_p2m_pmd(unsigned long addr, pte_t *pte_pg) 466 { 467 pte_t *ptechk; 468 pte_t *pte_newpg[PMDS_PER_MID_PAGE]; 469 pmd_t *pmdp; 470 unsigned int level; 471 unsigned long flags; 472 unsigned long vaddr; 473 int i; 474 475 /* Do all allocations first to bail out in error case. */ 476 for (i = 0; i < PMDS_PER_MID_PAGE; i++) { 477 pte_newpg[i] = alloc_p2m_page(); 478 if (!pte_newpg[i]) { 479 for (i--; i >= 0; i--) 480 free_p2m_page(pte_newpg[i]); 481 482 return NULL; 483 } 484 } 485 486 vaddr = addr & ~(PMD_SIZE * PMDS_PER_MID_PAGE - 1); 487 488 for (i = 0; i < PMDS_PER_MID_PAGE; i++) { 489 copy_page(pte_newpg[i], pte_pg); 490 paravirt_alloc_pte(&init_mm, __pa(pte_newpg[i]) >> PAGE_SHIFT); 491 492 pmdp = lookup_pmd_address(vaddr); 493 BUG_ON(!pmdp); 494 495 spin_lock_irqsave(&p2m_update_lock, flags); 496 497 ptechk = lookup_address(vaddr, &level); 498 if (ptechk == pte_pg) { 499 HYPERVISOR_shared_info->arch.p2m_generation++; 500 wmb(); /* Tools are synchronizing via p2m_generation. */ 501 set_pmd(pmdp, 502 __pmd(__pa(pte_newpg[i]) | _KERNPG_TABLE)); 503 wmb(); /* Tools are synchronizing via p2m_generation. */ 504 HYPERVISOR_shared_info->arch.p2m_generation++; 505 pte_newpg[i] = NULL; 506 } 507 508 spin_unlock_irqrestore(&p2m_update_lock, flags); 509 510 if (pte_newpg[i]) { 511 paravirt_release_pte(__pa(pte_newpg[i]) >> PAGE_SHIFT); 512 free_p2m_page(pte_newpg[i]); 513 } 514 515 vaddr += PMD_SIZE; 516 } 517 518 return lookup_address(addr, &level); 519 } 520 521 /* 522 * Fully allocate the p2m structure for a given pfn. We need to check 523 * that both the top and mid levels are allocated, and make sure the 524 * parallel mfn tree is kept in sync. We may race with other cpus, so 525 * the new pages are installed with cmpxchg; if we lose the race then 526 * simply free the page we allocated and use the one that's there. 527 */ 528 int xen_alloc_p2m_entry(unsigned long pfn) 529 { 530 unsigned topidx; 531 unsigned long *top_mfn_p, *mid_mfn; 532 pte_t *ptep, *pte_pg; 533 unsigned int level; 534 unsigned long flags; 535 unsigned long addr = (unsigned long)(xen_p2m_addr + pfn); 536 unsigned long p2m_pfn; 537 538 ptep = lookup_address(addr, &level); 539 BUG_ON(!ptep || level != PG_LEVEL_4K); 540 pte_pg = (pte_t *)((unsigned long)ptep & ~(PAGE_SIZE - 1)); 541 542 if (pte_pg == p2m_missing_pte || pte_pg == p2m_identity_pte) { 543 /* PMD level is missing, allocate a new one */ 544 ptep = alloc_p2m_pmd(addr, pte_pg); 545 if (!ptep) 546 return -ENOMEM; 547 } 548 549 if (p2m_top_mfn && pfn < MAX_P2M_PFN) { 550 topidx = p2m_top_index(pfn); 551 top_mfn_p = &p2m_top_mfn[topidx]; 552 mid_mfn = READ_ONCE(p2m_top_mfn_p[topidx]); 553 554 BUG_ON(virt_to_mfn(mid_mfn) != *top_mfn_p); 555 556 if (mid_mfn == p2m_mid_missing_mfn) { 557 /* Separately check the mid mfn level */ 558 unsigned long missing_mfn; 559 unsigned long mid_mfn_mfn; 560 unsigned long old_mfn; 561 562 mid_mfn = alloc_p2m_page(); 563 if (!mid_mfn) 564 return -ENOMEM; 565 566 p2m_mid_mfn_init(mid_mfn, p2m_missing); 567 568 missing_mfn = virt_to_mfn(p2m_mid_missing_mfn); 569 mid_mfn_mfn = virt_to_mfn(mid_mfn); 570 old_mfn = cmpxchg(top_mfn_p, missing_mfn, mid_mfn_mfn); 571 if (old_mfn != missing_mfn) { 572 free_p2m_page(mid_mfn); 573 mid_mfn = mfn_to_virt(old_mfn); 574 } else { 575 p2m_top_mfn_p[topidx] = mid_mfn; 576 } 577 } 578 } else { 579 mid_mfn = NULL; 580 } 581 582 p2m_pfn = pte_pfn(READ_ONCE(*ptep)); 583 if (p2m_pfn == PFN_DOWN(__pa(p2m_identity)) || 584 p2m_pfn == PFN_DOWN(__pa(p2m_missing))) { 585 /* p2m leaf page is missing */ 586 unsigned long *p2m; 587 588 p2m = alloc_p2m_page(); 589 if (!p2m) 590 return -ENOMEM; 591 592 if (p2m_pfn == PFN_DOWN(__pa(p2m_missing))) 593 p2m_init(p2m); 594 else 595 p2m_init_identity(p2m, pfn & ~(P2M_PER_PAGE - 1)); 596 597 spin_lock_irqsave(&p2m_update_lock, flags); 598 599 if (pte_pfn(*ptep) == p2m_pfn) { 600 HYPERVISOR_shared_info->arch.p2m_generation++; 601 wmb(); /* Tools are synchronizing via p2m_generation. */ 602 set_pte(ptep, 603 pfn_pte(PFN_DOWN(__pa(p2m)), PAGE_KERNEL)); 604 wmb(); /* Tools are synchronizing via p2m_generation. */ 605 HYPERVISOR_shared_info->arch.p2m_generation++; 606 if (mid_mfn) 607 mid_mfn[p2m_mid_index(pfn)] = virt_to_mfn(p2m); 608 p2m = NULL; 609 } 610 611 spin_unlock_irqrestore(&p2m_update_lock, flags); 612 613 if (p2m) 614 free_p2m_page(p2m); 615 } 616 617 /* Expanded the p2m? */ 618 if (pfn > xen_p2m_last_pfn) { 619 xen_p2m_last_pfn = pfn; 620 HYPERVISOR_shared_info->arch.max_pfn = xen_p2m_last_pfn; 621 } 622 623 return 0; 624 } 625 EXPORT_SYMBOL(xen_alloc_p2m_entry); 626 627 unsigned long __init set_phys_range_identity(unsigned long pfn_s, 628 unsigned long pfn_e) 629 { 630 unsigned long pfn; 631 632 if (unlikely(pfn_s >= xen_p2m_size)) 633 return 0; 634 635 if (pfn_s > pfn_e) 636 return 0; 637 638 if (pfn_e > xen_p2m_size) 639 pfn_e = xen_p2m_size; 640 641 for (pfn = pfn_s; pfn < pfn_e; pfn++) 642 xen_p2m_addr[pfn] = IDENTITY_FRAME(pfn); 643 644 return pfn - pfn_s; 645 } 646 647 bool __set_phys_to_machine(unsigned long pfn, unsigned long mfn) 648 { 649 pte_t *ptep; 650 unsigned int level; 651 652 if (unlikely(pfn >= xen_p2m_size)) { 653 BUG_ON(mfn != INVALID_P2M_ENTRY); 654 return true; 655 } 656 657 /* 658 * The interface requires atomic updates on p2m elements. 659 * xen_safe_write_ulong() is using an atomic store via asm(). 660 */ 661 if (likely(!xen_safe_write_ulong(xen_p2m_addr + pfn, mfn))) 662 return true; 663 664 ptep = lookup_address((unsigned long)(xen_p2m_addr + pfn), &level); 665 BUG_ON(!ptep || level != PG_LEVEL_4K); 666 667 if (pte_pfn(*ptep) == PFN_DOWN(__pa(p2m_missing))) 668 return mfn == INVALID_P2M_ENTRY; 669 670 if (pte_pfn(*ptep) == PFN_DOWN(__pa(p2m_identity))) 671 return mfn == IDENTITY_FRAME(pfn); 672 673 return false; 674 } 675 676 bool set_phys_to_machine(unsigned long pfn, unsigned long mfn) 677 { 678 if (unlikely(!__set_phys_to_machine(pfn, mfn))) { 679 int ret; 680 681 ret = xen_alloc_p2m_entry(pfn); 682 if (ret < 0) 683 return false; 684 685 return __set_phys_to_machine(pfn, mfn); 686 } 687 688 return true; 689 } 690 691 int set_foreign_p2m_mapping(struct gnttab_map_grant_ref *map_ops, 692 struct gnttab_map_grant_ref *kmap_ops, 693 struct page **pages, unsigned int count) 694 { 695 int i, ret = 0; 696 pte_t *pte; 697 698 if (xen_feature(XENFEAT_auto_translated_physmap)) 699 return 0; 700 701 if (kmap_ops) { 702 ret = HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, 703 kmap_ops, count); 704 if (ret) 705 goto out; 706 } 707 708 for (i = 0; i < count; i++) { 709 unsigned long mfn, pfn; 710 711 /* Do not add to override if the map failed. */ 712 if (map_ops[i].status) 713 continue; 714 715 if (map_ops[i].flags & GNTMAP_contains_pte) { 716 pte = (pte_t *)(mfn_to_virt(PFN_DOWN(map_ops[i].host_addr)) + 717 (map_ops[i].host_addr & ~PAGE_MASK)); 718 mfn = pte_mfn(*pte); 719 } else { 720 mfn = PFN_DOWN(map_ops[i].dev_bus_addr); 721 } 722 pfn = page_to_pfn(pages[i]); 723 724 WARN(pfn_to_mfn(pfn) != INVALID_P2M_ENTRY, "page must be ballooned"); 725 726 if (unlikely(!set_phys_to_machine(pfn, FOREIGN_FRAME(mfn)))) { 727 ret = -ENOMEM; 728 goto out; 729 } 730 } 731 732 out: 733 return ret; 734 } 735 EXPORT_SYMBOL_GPL(set_foreign_p2m_mapping); 736 737 int clear_foreign_p2m_mapping(struct gnttab_unmap_grant_ref *unmap_ops, 738 struct gnttab_unmap_grant_ref *kunmap_ops, 739 struct page **pages, unsigned int count) 740 { 741 int i, ret = 0; 742 743 if (xen_feature(XENFEAT_auto_translated_physmap)) 744 return 0; 745 746 for (i = 0; i < count; i++) { 747 unsigned long mfn = __pfn_to_mfn(page_to_pfn(pages[i])); 748 unsigned long pfn = page_to_pfn(pages[i]); 749 750 if (mfn == INVALID_P2M_ENTRY || !(mfn & FOREIGN_FRAME_BIT)) { 751 ret = -EINVAL; 752 goto out; 753 } 754 755 set_phys_to_machine(pfn, INVALID_P2M_ENTRY); 756 } 757 if (kunmap_ops) 758 ret = HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, 759 kunmap_ops, count); 760 out: 761 return ret; 762 } 763 EXPORT_SYMBOL_GPL(clear_foreign_p2m_mapping); 764 765 #ifdef CONFIG_XEN_DEBUG_FS 766 #include <linux/debugfs.h> 767 #include "debugfs.h" 768 static int p2m_dump_show(struct seq_file *m, void *v) 769 { 770 static const char * const type_name[] = { 771 [P2M_TYPE_IDENTITY] = "identity", 772 [P2M_TYPE_MISSING] = "missing", 773 [P2M_TYPE_PFN] = "pfn", 774 [P2M_TYPE_UNKNOWN] = "abnormal"}; 775 unsigned long pfn, first_pfn; 776 int type, prev_type; 777 778 prev_type = xen_p2m_elem_type(0); 779 first_pfn = 0; 780 781 for (pfn = 0; pfn < xen_p2m_size; pfn++) { 782 type = xen_p2m_elem_type(pfn); 783 if (type != prev_type) { 784 seq_printf(m, " [0x%lx->0x%lx] %s\n", first_pfn, pfn, 785 type_name[prev_type]); 786 prev_type = type; 787 first_pfn = pfn; 788 } 789 } 790 seq_printf(m, " [0x%lx->0x%lx] %s\n", first_pfn, pfn, 791 type_name[prev_type]); 792 return 0; 793 } 794 795 static int p2m_dump_open(struct inode *inode, struct file *filp) 796 { 797 return single_open(filp, p2m_dump_show, NULL); 798 } 799 800 static const struct file_operations p2m_dump_fops = { 801 .open = p2m_dump_open, 802 .read = seq_read, 803 .llseek = seq_lseek, 804 .release = single_release, 805 }; 806 807 static struct dentry *d_mmu_debug; 808 809 static int __init xen_p2m_debugfs(void) 810 { 811 struct dentry *d_xen = xen_init_debugfs(); 812 813 if (d_xen == NULL) 814 return -ENOMEM; 815 816 d_mmu_debug = debugfs_create_dir("mmu", d_xen); 817 818 debugfs_create_file("p2m", 0600, d_mmu_debug, NULL, &p2m_dump_fops); 819 return 0; 820 } 821 fs_initcall(xen_p2m_debugfs); 822 #endif /* CONFIG_XEN_DEBUG_FS */ 823