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 #include <linux/acpi.h> 74 75 #include <asm/cache.h> 76 #include <asm/setup.h> 77 #include <linux/uaccess.h> 78 79 #include <asm/xen/page.h> 80 #include <asm/xen/hypercall.h> 81 #include <asm/xen/hypervisor.h> 82 #include <xen/balloon.h> 83 #include <xen/grant_table.h> 84 #include <xen/hvc-console.h> 85 86 #include "xen-ops.h" 87 88 #define P2M_MID_PER_PAGE (PAGE_SIZE / sizeof(unsigned long *)) 89 #define P2M_TOP_PER_PAGE (PAGE_SIZE / sizeof(unsigned long **)) 90 91 #define MAX_P2M_PFN (P2M_TOP_PER_PAGE * P2M_MID_PER_PAGE * P2M_PER_PAGE) 92 93 #define PMDS_PER_MID_PAGE (P2M_MID_PER_PAGE / PTRS_PER_PTE) 94 95 unsigned long *xen_p2m_addr __read_mostly; 96 EXPORT_SYMBOL_GPL(xen_p2m_addr); 97 unsigned long xen_p2m_size __read_mostly; 98 EXPORT_SYMBOL_GPL(xen_p2m_size); 99 unsigned long xen_max_p2m_pfn __read_mostly; 100 EXPORT_SYMBOL_GPL(xen_max_p2m_pfn); 101 102 #ifdef CONFIG_XEN_MEMORY_HOTPLUG_LIMIT 103 #define P2M_LIMIT CONFIG_XEN_MEMORY_HOTPLUG_LIMIT 104 #else 105 #define P2M_LIMIT 0 106 #endif 107 108 static DEFINE_SPINLOCK(p2m_update_lock); 109 110 static unsigned long *p2m_mid_missing_mfn; 111 static unsigned long *p2m_top_mfn; 112 static unsigned long **p2m_top_mfn_p; 113 static unsigned long *p2m_missing; 114 static unsigned long *p2m_identity; 115 static pte_t *p2m_missing_pte; 116 static pte_t *p2m_identity_pte; 117 118 /* 119 * Hint at last populated PFN. 120 * 121 * Used to set HYPERVISOR_shared_info->arch.max_pfn so the toolstack 122 * can avoid scanning the whole P2M (which may be sized to account for 123 * hotplugged memory). 124 */ 125 static unsigned long xen_p2m_last_pfn; 126 127 static inline unsigned p2m_top_index(unsigned long pfn) 128 { 129 BUG_ON(pfn >= MAX_P2M_PFN); 130 return pfn / (P2M_MID_PER_PAGE * P2M_PER_PAGE); 131 } 132 133 static inline unsigned p2m_mid_index(unsigned long pfn) 134 { 135 return (pfn / P2M_PER_PAGE) % P2M_MID_PER_PAGE; 136 } 137 138 static void p2m_top_mfn_init(unsigned long *top) 139 { 140 unsigned i; 141 142 for (i = 0; i < P2M_TOP_PER_PAGE; i++) 143 top[i] = virt_to_mfn(p2m_mid_missing_mfn); 144 } 145 146 static void p2m_top_mfn_p_init(unsigned long **top) 147 { 148 unsigned i; 149 150 for (i = 0; i < P2M_TOP_PER_PAGE; i++) 151 top[i] = p2m_mid_missing_mfn; 152 } 153 154 static void p2m_mid_mfn_init(unsigned long *mid, unsigned long *leaf) 155 { 156 unsigned i; 157 158 for (i = 0; i < P2M_MID_PER_PAGE; i++) 159 mid[i] = virt_to_mfn(leaf); 160 } 161 162 static void p2m_init(unsigned long *p2m) 163 { 164 unsigned i; 165 166 for (i = 0; i < P2M_PER_PAGE; i++) 167 p2m[i] = INVALID_P2M_ENTRY; 168 } 169 170 static void p2m_init_identity(unsigned long *p2m, unsigned long pfn) 171 { 172 unsigned i; 173 174 for (i = 0; i < P2M_PER_PAGE; i++) 175 p2m[i] = IDENTITY_FRAME(pfn + i); 176 } 177 178 static void * __ref alloc_p2m_page(void) 179 { 180 if (unlikely(!slab_is_available())) { 181 void *ptr = memblock_alloc(PAGE_SIZE, PAGE_SIZE); 182 183 if (!ptr) 184 panic("%s: Failed to allocate %lu bytes align=0x%lx\n", 185 __func__, PAGE_SIZE, PAGE_SIZE); 186 187 return ptr; 188 } 189 190 return (void *)__get_free_page(GFP_KERNEL); 191 } 192 193 static void __ref free_p2m_page(void *p) 194 { 195 if (unlikely(!slab_is_available())) { 196 memblock_free(p, PAGE_SIZE); 197 return; 198 } 199 200 free_page((unsigned long)p); 201 } 202 203 /* 204 * Build the parallel p2m_top_mfn and p2m_mid_mfn structures 205 * 206 * This is called both at boot time, and after resuming from suspend: 207 * - At boot time we're called rather early, and must use alloc_bootmem*() 208 * to allocate memory. 209 * 210 * - After resume we're called from within stop_machine, but the mfn 211 * tree should already be completely allocated. 212 */ 213 void __ref xen_build_mfn_list_list(void) 214 { 215 unsigned long pfn, mfn; 216 pte_t *ptep; 217 unsigned int level, topidx, mididx; 218 unsigned long *mid_mfn_p; 219 220 if (xen_start_info->flags & SIF_VIRT_P2M_4TOOLS) 221 return; 222 223 /* Pre-initialize p2m_top_mfn to be completely missing */ 224 if (p2m_top_mfn == NULL) { 225 p2m_mid_missing_mfn = alloc_p2m_page(); 226 p2m_mid_mfn_init(p2m_mid_missing_mfn, p2m_missing); 227 228 p2m_top_mfn_p = alloc_p2m_page(); 229 p2m_top_mfn_p_init(p2m_top_mfn_p); 230 231 p2m_top_mfn = alloc_p2m_page(); 232 p2m_top_mfn_init(p2m_top_mfn); 233 } else { 234 /* Reinitialise, mfn's all change after migration */ 235 p2m_mid_mfn_init(p2m_mid_missing_mfn, p2m_missing); 236 } 237 238 for (pfn = 0; pfn < xen_max_p2m_pfn && pfn < MAX_P2M_PFN; 239 pfn += P2M_PER_PAGE) { 240 topidx = p2m_top_index(pfn); 241 mididx = p2m_mid_index(pfn); 242 243 mid_mfn_p = p2m_top_mfn_p[topidx]; 244 ptep = lookup_address((unsigned long)(xen_p2m_addr + pfn), 245 &level); 246 BUG_ON(!ptep || level != PG_LEVEL_4K); 247 mfn = pte_mfn(*ptep); 248 ptep = (pte_t *)((unsigned long)ptep & ~(PAGE_SIZE - 1)); 249 250 /* Don't bother allocating any mfn mid levels if 251 * they're just missing, just update the stored mfn, 252 * since all could have changed over a migrate. 253 */ 254 if (ptep == p2m_missing_pte || ptep == p2m_identity_pte) { 255 BUG_ON(mididx); 256 BUG_ON(mid_mfn_p != p2m_mid_missing_mfn); 257 p2m_top_mfn[topidx] = virt_to_mfn(p2m_mid_missing_mfn); 258 pfn += (P2M_MID_PER_PAGE - 1) * P2M_PER_PAGE; 259 continue; 260 } 261 262 if (mid_mfn_p == p2m_mid_missing_mfn) { 263 mid_mfn_p = alloc_p2m_page(); 264 p2m_mid_mfn_init(mid_mfn_p, p2m_missing); 265 266 p2m_top_mfn_p[topidx] = mid_mfn_p; 267 } 268 269 p2m_top_mfn[topidx] = virt_to_mfn(mid_mfn_p); 270 mid_mfn_p[mididx] = mfn; 271 } 272 } 273 274 void xen_setup_mfn_list_list(void) 275 { 276 BUG_ON(HYPERVISOR_shared_info == &xen_dummy_shared_info); 277 278 if (xen_start_info->flags & SIF_VIRT_P2M_4TOOLS) 279 HYPERVISOR_shared_info->arch.pfn_to_mfn_frame_list_list = ~0UL; 280 else 281 HYPERVISOR_shared_info->arch.pfn_to_mfn_frame_list_list = 282 virt_to_mfn(p2m_top_mfn); 283 HYPERVISOR_shared_info->arch.max_pfn = xen_p2m_last_pfn; 284 HYPERVISOR_shared_info->arch.p2m_generation = 0; 285 HYPERVISOR_shared_info->arch.p2m_vaddr = (unsigned long)xen_p2m_addr; 286 HYPERVISOR_shared_info->arch.p2m_cr3 = 287 xen_pfn_to_cr3(virt_to_mfn(swapper_pg_dir)); 288 } 289 290 /* Set up p2m_top to point to the domain-builder provided p2m pages */ 291 void __init xen_build_dynamic_phys_to_machine(void) 292 { 293 unsigned long pfn; 294 295 xen_p2m_addr = (unsigned long *)xen_start_info->mfn_list; 296 xen_p2m_size = ALIGN(xen_start_info->nr_pages, P2M_PER_PAGE); 297 298 for (pfn = xen_start_info->nr_pages; pfn < xen_p2m_size; pfn++) 299 xen_p2m_addr[pfn] = INVALID_P2M_ENTRY; 300 301 xen_max_p2m_pfn = xen_p2m_size; 302 } 303 304 #define P2M_TYPE_IDENTITY 0 305 #define P2M_TYPE_MISSING 1 306 #define P2M_TYPE_PFN 2 307 #define P2M_TYPE_UNKNOWN 3 308 309 static int xen_p2m_elem_type(unsigned long pfn) 310 { 311 unsigned long mfn; 312 313 if (pfn >= xen_p2m_size) 314 return P2M_TYPE_IDENTITY; 315 316 mfn = xen_p2m_addr[pfn]; 317 318 if (mfn == INVALID_P2M_ENTRY) 319 return P2M_TYPE_MISSING; 320 321 if (mfn & IDENTITY_FRAME_BIT) 322 return P2M_TYPE_IDENTITY; 323 324 return P2M_TYPE_PFN; 325 } 326 327 static void __init xen_rebuild_p2m_list(unsigned long *p2m) 328 { 329 unsigned int i, chunk; 330 unsigned long pfn; 331 unsigned long *mfns; 332 pte_t *ptep; 333 pmd_t *pmdp; 334 int type; 335 336 p2m_missing = alloc_p2m_page(); 337 p2m_init(p2m_missing); 338 p2m_identity = alloc_p2m_page(); 339 p2m_init(p2m_identity); 340 341 p2m_missing_pte = alloc_p2m_page(); 342 paravirt_alloc_pte(&init_mm, __pa(p2m_missing_pte) >> PAGE_SHIFT); 343 p2m_identity_pte = alloc_p2m_page(); 344 paravirt_alloc_pte(&init_mm, __pa(p2m_identity_pte) >> PAGE_SHIFT); 345 for (i = 0; i < PTRS_PER_PTE; i++) { 346 set_pte(p2m_missing_pte + i, 347 pfn_pte(PFN_DOWN(__pa(p2m_missing)), PAGE_KERNEL_RO)); 348 set_pte(p2m_identity_pte + i, 349 pfn_pte(PFN_DOWN(__pa(p2m_identity)), PAGE_KERNEL_RO)); 350 } 351 352 for (pfn = 0; pfn < xen_max_p2m_pfn; pfn += chunk) { 353 /* 354 * Try to map missing/identity PMDs or p2m-pages if possible. 355 * We have to respect the structure of the mfn_list_list 356 * which will be built just afterwards. 357 * Chunk size to test is one p2m page if we are in the middle 358 * of a mfn_list_list mid page and the complete mid page area 359 * if we are at index 0 of the mid page. Please note that a 360 * mid page might cover more than one PMD, e.g. on 32 bit PAE 361 * kernels. 362 */ 363 chunk = (pfn & (P2M_PER_PAGE * P2M_MID_PER_PAGE - 1)) ? 364 P2M_PER_PAGE : P2M_PER_PAGE * P2M_MID_PER_PAGE; 365 366 type = xen_p2m_elem_type(pfn); 367 i = 0; 368 if (type != P2M_TYPE_PFN) 369 for (i = 1; i < chunk; i++) 370 if (xen_p2m_elem_type(pfn + i) != type) 371 break; 372 if (i < chunk) 373 /* Reset to minimal chunk size. */ 374 chunk = P2M_PER_PAGE; 375 376 if (type == P2M_TYPE_PFN || i < chunk) { 377 /* Use initial p2m page contents. */ 378 mfns = alloc_p2m_page(); 379 copy_page(mfns, xen_p2m_addr + pfn); 380 ptep = populate_extra_pte((unsigned long)(p2m + pfn)); 381 set_pte(ptep, 382 pfn_pte(PFN_DOWN(__pa(mfns)), PAGE_KERNEL)); 383 continue; 384 } 385 386 if (chunk == P2M_PER_PAGE) { 387 /* Map complete missing or identity p2m-page. */ 388 mfns = (type == P2M_TYPE_MISSING) ? 389 p2m_missing : p2m_identity; 390 ptep = populate_extra_pte((unsigned long)(p2m + pfn)); 391 set_pte(ptep, 392 pfn_pte(PFN_DOWN(__pa(mfns)), PAGE_KERNEL_RO)); 393 continue; 394 } 395 396 /* Complete missing or identity PMD(s) can be mapped. */ 397 ptep = (type == P2M_TYPE_MISSING) ? 398 p2m_missing_pte : p2m_identity_pte; 399 for (i = 0; i < PMDS_PER_MID_PAGE; i++) { 400 pmdp = populate_extra_pmd( 401 (unsigned long)(p2m + pfn) + i * PMD_SIZE); 402 set_pmd(pmdp, __pmd(__pa(ptep) | _KERNPG_TABLE)); 403 } 404 } 405 } 406 407 void __init xen_vmalloc_p2m_tree(void) 408 { 409 static struct vm_struct vm; 410 unsigned long p2m_limit; 411 412 xen_p2m_last_pfn = xen_max_p2m_pfn; 413 414 p2m_limit = (phys_addr_t)P2M_LIMIT * 1024 * 1024 * 1024 / PAGE_SIZE; 415 vm.flags = VM_ALLOC; 416 vm.size = ALIGN(sizeof(unsigned long) * max(xen_max_p2m_pfn, p2m_limit), 417 PMD_SIZE * PMDS_PER_MID_PAGE); 418 vm_area_register_early(&vm, PMD_SIZE * PMDS_PER_MID_PAGE); 419 pr_notice("p2m virtual area at %p, size is %lx\n", vm.addr, vm.size); 420 421 xen_max_p2m_pfn = vm.size / sizeof(unsigned long); 422 423 xen_rebuild_p2m_list(vm.addr); 424 425 xen_p2m_addr = vm.addr; 426 xen_p2m_size = xen_max_p2m_pfn; 427 428 xen_inv_extra_mem(); 429 } 430 431 unsigned long get_phys_to_machine(unsigned long pfn) 432 { 433 pte_t *ptep; 434 unsigned int level; 435 436 if (unlikely(pfn >= xen_p2m_size)) { 437 if (pfn < xen_max_p2m_pfn) 438 return xen_chk_extra_mem(pfn); 439 440 return IDENTITY_FRAME(pfn); 441 } 442 443 ptep = lookup_address((unsigned long)(xen_p2m_addr + pfn), &level); 444 BUG_ON(!ptep || level != PG_LEVEL_4K); 445 446 /* 447 * The INVALID_P2M_ENTRY is filled in both p2m_*identity 448 * and in p2m_*missing, so returning the INVALID_P2M_ENTRY 449 * would be wrong. 450 */ 451 if (pte_pfn(*ptep) == PFN_DOWN(__pa(p2m_identity))) 452 return IDENTITY_FRAME(pfn); 453 454 return xen_p2m_addr[pfn]; 455 } 456 EXPORT_SYMBOL_GPL(get_phys_to_machine); 457 458 /* 459 * Allocate new pmd(s). It is checked whether the old pmd is still in place. 460 * If not, nothing is changed. This is okay as the only reason for allocating 461 * a new pmd is to replace p2m_missing_pte or p2m_identity_pte by a individual 462 * pmd. 463 */ 464 static pte_t *alloc_p2m_pmd(unsigned long addr, pte_t *pte_pg) 465 { 466 pte_t *ptechk; 467 pte_t *pte_newpg[PMDS_PER_MID_PAGE]; 468 pmd_t *pmdp; 469 unsigned int level; 470 unsigned long flags; 471 unsigned long vaddr; 472 int i; 473 474 /* Do all allocations first to bail out in error case. */ 475 for (i = 0; i < PMDS_PER_MID_PAGE; i++) { 476 pte_newpg[i] = alloc_p2m_page(); 477 if (!pte_newpg[i]) { 478 for (i--; i >= 0; i--) 479 free_p2m_page(pte_newpg[i]); 480 481 return NULL; 482 } 483 } 484 485 vaddr = addr & ~(PMD_SIZE * PMDS_PER_MID_PAGE - 1); 486 487 for (i = 0; i < PMDS_PER_MID_PAGE; i++) { 488 copy_page(pte_newpg[i], pte_pg); 489 paravirt_alloc_pte(&init_mm, __pa(pte_newpg[i]) >> PAGE_SHIFT); 490 491 pmdp = lookup_pmd_address(vaddr); 492 BUG_ON(!pmdp); 493 494 spin_lock_irqsave(&p2m_update_lock, flags); 495 496 ptechk = lookup_address(vaddr, &level); 497 if (ptechk == pte_pg) { 498 HYPERVISOR_shared_info->arch.p2m_generation++; 499 wmb(); /* Tools are synchronizing via p2m_generation. */ 500 set_pmd(pmdp, 501 __pmd(__pa(pte_newpg[i]) | _KERNPG_TABLE)); 502 wmb(); /* Tools are synchronizing via p2m_generation. */ 503 HYPERVISOR_shared_info->arch.p2m_generation++; 504 pte_newpg[i] = NULL; 505 } 506 507 spin_unlock_irqrestore(&p2m_update_lock, flags); 508 509 if (pte_newpg[i]) { 510 paravirt_release_pte(__pa(pte_newpg[i]) >> PAGE_SHIFT); 511 free_p2m_page(pte_newpg[i]); 512 } 513 514 vaddr += PMD_SIZE; 515 } 516 517 return lookup_address(addr, &level); 518 } 519 520 /* 521 * Fully allocate the p2m structure for a given pfn. We need to check 522 * that both the top and mid levels are allocated, and make sure the 523 * parallel mfn tree is kept in sync. We may race with other cpus, so 524 * the new pages are installed with cmpxchg; if we lose the race then 525 * simply free the page we allocated and use the one that's there. 526 */ 527 int xen_alloc_p2m_entry(unsigned long pfn) 528 { 529 unsigned topidx; 530 unsigned long *top_mfn_p, *mid_mfn; 531 pte_t *ptep, *pte_pg; 532 unsigned int level; 533 unsigned long flags; 534 unsigned long addr = (unsigned long)(xen_p2m_addr + pfn); 535 unsigned long p2m_pfn; 536 537 ptep = lookup_address(addr, &level); 538 BUG_ON(!ptep || level != PG_LEVEL_4K); 539 pte_pg = (pte_t *)((unsigned long)ptep & ~(PAGE_SIZE - 1)); 540 541 if (pte_pg == p2m_missing_pte || pte_pg == p2m_identity_pte) { 542 /* PMD level is missing, allocate a new one */ 543 ptep = alloc_p2m_pmd(addr, pte_pg); 544 if (!ptep) 545 return -ENOMEM; 546 } 547 548 if (p2m_top_mfn && pfn < MAX_P2M_PFN) { 549 topidx = p2m_top_index(pfn); 550 top_mfn_p = &p2m_top_mfn[topidx]; 551 mid_mfn = READ_ONCE(p2m_top_mfn_p[topidx]); 552 553 BUG_ON(virt_to_mfn(mid_mfn) != *top_mfn_p); 554 555 if (mid_mfn == p2m_mid_missing_mfn) { 556 /* Separately check the mid mfn level */ 557 unsigned long missing_mfn; 558 unsigned long mid_mfn_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 /* try_cmpxchg() updates missing_mfn on failure. */ 569 if (try_cmpxchg(top_mfn_p, &missing_mfn, mid_mfn_mfn)) { 570 p2m_top_mfn_p[topidx] = mid_mfn; 571 } else { 572 free_p2m_page(mid_mfn); 573 mid_mfn = mfn_to_virt(missing_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 = ALIGN(pfn + 1, P2M_PER_PAGE); 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 /* Only invalid entries allowed above the highest p2m covered frame. */ 651 if (unlikely(pfn >= xen_p2m_size)) 652 return mfn == INVALID_P2M_ENTRY; 653 654 /* 655 * The interface requires atomic updates on p2m elements. 656 * xen_safe_write_ulong() is using an atomic store via asm(). 657 */ 658 if (likely(!xen_safe_write_ulong(xen_p2m_addr + pfn, mfn))) 659 return true; 660 661 ptep = lookup_address((unsigned long)(xen_p2m_addr + pfn), &level); 662 BUG_ON(!ptep || level != PG_LEVEL_4K); 663 664 if (pte_pfn(*ptep) == PFN_DOWN(__pa(p2m_missing))) 665 return mfn == INVALID_P2M_ENTRY; 666 667 if (pte_pfn(*ptep) == PFN_DOWN(__pa(p2m_identity))) 668 return mfn == IDENTITY_FRAME(pfn); 669 670 return false; 671 } 672 673 bool set_phys_to_machine(unsigned long pfn, unsigned long mfn) 674 { 675 if (unlikely(!__set_phys_to_machine(pfn, mfn))) { 676 int ret; 677 678 ret = xen_alloc_p2m_entry(pfn); 679 if (ret < 0) 680 return false; 681 682 return __set_phys_to_machine(pfn, mfn); 683 } 684 685 return true; 686 } 687 688 int set_foreign_p2m_mapping(struct gnttab_map_grant_ref *map_ops, 689 struct gnttab_map_grant_ref *kmap_ops, 690 struct page **pages, unsigned int count) 691 { 692 int i, ret = 0; 693 pte_t *pte; 694 695 if (xen_feature(XENFEAT_auto_translated_physmap)) 696 return 0; 697 698 if (kmap_ops) { 699 ret = HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, 700 kmap_ops, count); 701 if (ret) 702 goto out; 703 } 704 705 for (i = 0; i < count; i++) { 706 unsigned long mfn, pfn; 707 struct gnttab_unmap_grant_ref unmap[2]; 708 int rc; 709 710 /* Do not add to override if the map failed. */ 711 if (map_ops[i].status != GNTST_okay || 712 (kmap_ops && kmap_ops[i].status != GNTST_okay)) 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 (likely(set_phys_to_machine(pfn, FOREIGN_FRAME(mfn)))) 727 continue; 728 729 /* 730 * Signal an error for this slot. This in turn requires 731 * immediate unmapping. 732 */ 733 map_ops[i].status = GNTST_general_error; 734 unmap[0].host_addr = map_ops[i].host_addr; 735 unmap[0].handle = map_ops[i].handle; 736 map_ops[i].handle = INVALID_GRANT_HANDLE; 737 if (map_ops[i].flags & GNTMAP_device_map) 738 unmap[0].dev_bus_addr = map_ops[i].dev_bus_addr; 739 else 740 unmap[0].dev_bus_addr = 0; 741 742 if (kmap_ops) { 743 kmap_ops[i].status = GNTST_general_error; 744 unmap[1].host_addr = kmap_ops[i].host_addr; 745 unmap[1].handle = kmap_ops[i].handle; 746 kmap_ops[i].handle = INVALID_GRANT_HANDLE; 747 if (kmap_ops[i].flags & GNTMAP_device_map) 748 unmap[1].dev_bus_addr = kmap_ops[i].dev_bus_addr; 749 else 750 unmap[1].dev_bus_addr = 0; 751 } 752 753 /* 754 * Pre-populate both status fields, to be recognizable in 755 * the log message below. 756 */ 757 unmap[0].status = 1; 758 unmap[1].status = 1; 759 760 rc = HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, 761 unmap, 1 + !!kmap_ops); 762 if (rc || unmap[0].status != GNTST_okay || 763 unmap[1].status != GNTST_okay) 764 pr_err_once("gnttab unmap failed: rc=%d st0=%d st1=%d\n", 765 rc, unmap[0].status, unmap[1].status); 766 } 767 768 out: 769 return ret; 770 } 771 772 int clear_foreign_p2m_mapping(struct gnttab_unmap_grant_ref *unmap_ops, 773 struct gnttab_unmap_grant_ref *kunmap_ops, 774 struct page **pages, unsigned int count) 775 { 776 int i, ret = 0; 777 778 if (xen_feature(XENFEAT_auto_translated_physmap)) 779 return 0; 780 781 for (i = 0; i < count; i++) { 782 unsigned long mfn = __pfn_to_mfn(page_to_pfn(pages[i])); 783 unsigned long pfn = page_to_pfn(pages[i]); 784 785 if (mfn != INVALID_P2M_ENTRY && (mfn & FOREIGN_FRAME_BIT)) 786 set_phys_to_machine(pfn, INVALID_P2M_ENTRY); 787 else 788 ret = -EINVAL; 789 } 790 if (kunmap_ops) 791 ret = HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, 792 kunmap_ops, count) ?: ret; 793 794 return ret; 795 } 796 797 /* Remapped non-RAM areas */ 798 #define NR_NONRAM_REMAP 4 799 static struct nonram_remap { 800 phys_addr_t maddr; 801 phys_addr_t paddr; 802 size_t size; 803 } xen_nonram_remap[NR_NONRAM_REMAP] __ro_after_init; 804 static unsigned int nr_nonram_remap __ro_after_init; 805 806 /* 807 * Do the real remapping of non-RAM regions as specified in the 808 * xen_nonram_remap[] array. 809 * In case of an error just crash the system. 810 */ 811 void __init xen_do_remap_nonram(void) 812 { 813 unsigned int i; 814 unsigned int remapped = 0; 815 const struct nonram_remap *remap = xen_nonram_remap; 816 unsigned long pfn, mfn, end_pfn; 817 818 for (i = 0; i < nr_nonram_remap; i++) { 819 end_pfn = PFN_UP(remap->paddr + remap->size); 820 pfn = PFN_DOWN(remap->paddr); 821 mfn = PFN_DOWN(remap->maddr); 822 while (pfn < end_pfn) { 823 if (!set_phys_to_machine(pfn, mfn)) 824 panic("Failed to set p2m mapping for pfn=%lx mfn=%lx\n", 825 pfn, mfn); 826 827 pfn++; 828 mfn++; 829 remapped++; 830 } 831 832 remap++; 833 } 834 835 pr_info("Remapped %u non-RAM page(s)\n", remapped); 836 } 837 838 #ifdef CONFIG_ACPI 839 /* 840 * Xen variant of acpi_os_ioremap() taking potentially remapped non-RAM 841 * regions into account. 842 * Any attempt to map an area crossing a remap boundary will produce a 843 * WARN() splat. 844 * phys is related to remap->maddr on input and will be rebased to remap->paddr. 845 */ 846 static void __iomem *xen_acpi_os_ioremap(acpi_physical_address phys, 847 acpi_size size) 848 { 849 unsigned int i; 850 const struct nonram_remap *remap = xen_nonram_remap; 851 852 for (i = 0; i < nr_nonram_remap; i++) { 853 if (phys + size > remap->maddr && 854 phys < remap->maddr + remap->size) { 855 WARN_ON(phys < remap->maddr || 856 phys + size > remap->maddr + remap->size); 857 phys += remap->paddr - remap->maddr; 858 break; 859 } 860 } 861 862 return x86_acpi_os_ioremap(phys, size); 863 } 864 #endif /* CONFIG_ACPI */ 865 866 /* 867 * Add a new non-RAM remap entry. 868 * In case of no free entry found, just crash the system. 869 */ 870 void __init xen_add_remap_nonram(phys_addr_t maddr, phys_addr_t paddr, 871 unsigned long size) 872 { 873 BUG_ON((maddr & ~PAGE_MASK) != (paddr & ~PAGE_MASK)); 874 875 if (nr_nonram_remap == NR_NONRAM_REMAP) { 876 xen_raw_console_write("Number of required E820 entry remapping actions exceed maximum value\n"); 877 BUG(); 878 } 879 880 #ifdef CONFIG_ACPI 881 /* Switch to the Xen acpi_os_ioremap() variant. */ 882 if (nr_nonram_remap == 0) 883 acpi_os_ioremap = xen_acpi_os_ioremap; 884 #endif 885 886 xen_nonram_remap[nr_nonram_remap].maddr = maddr; 887 xen_nonram_remap[nr_nonram_remap].paddr = paddr; 888 xen_nonram_remap[nr_nonram_remap].size = size; 889 890 nr_nonram_remap++; 891 } 892 893 #ifdef CONFIG_XEN_DEBUG_FS 894 #include <linux/debugfs.h> 895 static int p2m_dump_show(struct seq_file *m, void *v) 896 { 897 static const char * const type_name[] = { 898 [P2M_TYPE_IDENTITY] = "identity", 899 [P2M_TYPE_MISSING] = "missing", 900 [P2M_TYPE_PFN] = "pfn", 901 [P2M_TYPE_UNKNOWN] = "abnormal"}; 902 unsigned long pfn, first_pfn; 903 int type, prev_type; 904 905 prev_type = xen_p2m_elem_type(0); 906 first_pfn = 0; 907 908 for (pfn = 0; pfn < xen_p2m_size; pfn++) { 909 type = xen_p2m_elem_type(pfn); 910 if (type != prev_type) { 911 seq_printf(m, " [0x%lx->0x%lx] %s\n", first_pfn, pfn, 912 type_name[prev_type]); 913 prev_type = type; 914 first_pfn = pfn; 915 } 916 } 917 seq_printf(m, " [0x%lx->0x%lx] %s\n", first_pfn, pfn, 918 type_name[prev_type]); 919 return 0; 920 } 921 922 DEFINE_SHOW_ATTRIBUTE(p2m_dump); 923 924 static struct dentry *d_mmu_debug; 925 926 static int __init xen_p2m_debugfs(void) 927 { 928 struct dentry *d_xen = xen_init_debugfs(); 929 930 d_mmu_debug = debugfs_create_dir("mmu", d_xen); 931 932 debugfs_create_file("p2m", 0600, d_mmu_debug, NULL, &p2m_dump_fops); 933 return 0; 934 } 935 fs_initcall(xen_p2m_debugfs); 936 #endif /* CONFIG_XEN_DEBUG_FS */ 937