1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause 3 * 4 * Copyright (c) 2021 Beckhoff Automation GmbH & Co. KG 5 * Author: Corvin Köhne <c.koehne@beckhoff.com> 6 */ 7 8 #include <sys/types.h> 9 #include <sys/queue.h> 10 11 #include <machine/vmm.h> 12 13 #include <assert.h> 14 #include <err.h> 15 #include <errno.h> 16 #include <stdio.h> 17 #include <stdlib.h> 18 #include <string.h> 19 20 #include "debug.h" 21 #include "e820.h" 22 #include "qemu_fwcfg.h" 23 24 /* 25 * E820 always uses 64 bit entries. Emulation code will use vm_paddr_t since it 26 * works on physical addresses. If vm_paddr_t is larger than uint64_t E820 can't 27 * hold all possible physical addresses and we can get into trouble. 28 */ 29 static_assert(sizeof(vm_paddr_t) <= sizeof(uint64_t), 30 "Unable to represent physical memory by E820 table"); 31 32 #define E820_FWCFG_FILE_NAME "etc/e820" 33 34 #define KB (1024UL) 35 #define MB (1024 * KB) 36 #define GB (1024 * MB) 37 38 /* 39 * Fix E820 memory holes: 40 * [ A0000, C0000) VGA 41 * [ C0000, 100000) ROM 42 */ 43 #define E820_VGA_MEM_BASE 0xA0000 44 #define E820_VGA_MEM_END 0xC0000 45 #define E820_ROM_MEM_BASE 0xC0000 46 #define E820_ROM_MEM_END 0x100000 47 48 struct e820_element { 49 TAILQ_ENTRY(e820_element) chain; 50 uint64_t base; 51 uint64_t end; 52 enum e820_memory_type type; 53 }; 54 static TAILQ_HEAD(e820_table, e820_element) e820_table = TAILQ_HEAD_INITIALIZER( 55 e820_table); 56 57 static struct e820_element * 58 e820_element_alloc(uint64_t base, uint64_t end, enum e820_memory_type type) 59 { 60 struct e820_element *element; 61 62 element = calloc(1, sizeof(*element)); 63 if (element == NULL) { 64 return (NULL); 65 } 66 67 element->base = base; 68 element->end = end; 69 element->type = type; 70 71 return (element); 72 } 73 74 static const char * 75 e820_get_type_name(const enum e820_memory_type type) 76 { 77 switch (type) { 78 case E820_TYPE_MEMORY: 79 return ("RAM"); 80 case E820_TYPE_RESERVED: 81 return ("Reserved"); 82 case E820_TYPE_ACPI: 83 return ("ACPI"); 84 case E820_TYPE_NVS: 85 return ("NVS"); 86 default: 87 return ("Unknown"); 88 } 89 } 90 91 void 92 e820_dump_table(void) 93 { 94 struct e820_element *element; 95 uint64_t i; 96 97 EPRINTLN("E820 map:"); 98 99 i = 0; 100 TAILQ_FOREACH(element, &e820_table, chain) { 101 EPRINTLN(" (%4lu) [%16lx, %16lx] %s", i, 102 element->base, element->end, 103 e820_get_type_name(element->type)); 104 105 ++i; 106 } 107 } 108 109 static struct qemu_fwcfg_item * 110 e820_get_fwcfg_item(void) 111 { 112 struct qemu_fwcfg_item *fwcfg_item; 113 struct e820_element *element; 114 struct e820_entry *entries; 115 int count, i; 116 117 count = 0; 118 TAILQ_FOREACH(element, &e820_table, chain) { 119 ++count; 120 } 121 if (count == 0) { 122 warnx("%s: E820 table empty", __func__); 123 return (NULL); 124 } 125 126 fwcfg_item = calloc(1, sizeof(struct qemu_fwcfg_item)); 127 if (fwcfg_item == NULL) { 128 return (NULL); 129 } 130 131 fwcfg_item->size = count * sizeof(struct e820_entry); 132 fwcfg_item->data = calloc(count, sizeof(struct e820_entry)); 133 if (fwcfg_item->data == NULL) { 134 free(fwcfg_item); 135 return (NULL); 136 } 137 138 i = 0; 139 entries = (struct e820_entry *)fwcfg_item->data; 140 TAILQ_FOREACH(element, &e820_table, chain) { 141 struct e820_entry *entry = &entries[i]; 142 143 entry->base = element->base; 144 entry->length = element->end - element->base; 145 entry->type = element->type; 146 147 ++i; 148 } 149 150 return (fwcfg_item); 151 } 152 153 static int 154 e820_add_entry(const uint64_t base, const uint64_t end, 155 const enum e820_memory_type type) 156 { 157 struct e820_element *new_element; 158 struct e820_element *element; 159 struct e820_element *ram_element; 160 161 assert(end >= base); 162 163 new_element = e820_element_alloc(base, end, type); 164 if (new_element == NULL) { 165 return (ENOMEM); 166 } 167 168 /* 169 * E820 table should always be sorted in ascending order. Therefore, 170 * search for a range whose end is larger than the base parameter. 171 */ 172 TAILQ_FOREACH(element, &e820_table, chain) { 173 if (element->end > base) { 174 break; 175 } 176 } 177 178 /* 179 * System memory requires special handling. 180 */ 181 if (type == E820_TYPE_MEMORY) { 182 /* 183 * base is larger than of any existing element. Add new system 184 * memory at the end of the table. 185 */ 186 if (element == NULL) { 187 TAILQ_INSERT_TAIL(&e820_table, new_element, chain); 188 return (0); 189 } 190 191 /* 192 * System memory shouldn't overlap with any existing element. 193 */ 194 assert(end >= element->base); 195 196 TAILQ_INSERT_BEFORE(element, new_element, chain); 197 198 return (0); 199 } 200 201 /* 202 * If some one tries to allocate a specific address, it could happen, that 203 * this address is not allocatable. Therefore, do some checks. If the 204 * address is not allocatable, don't panic. The user may have a fallback and 205 * tries to allocate another address. This is true for the GVT-d emulation 206 * which tries to reuse the host address of the graphics stolen memory and 207 * falls back to allocating the highest address below 4 GB. 208 */ 209 if (element == NULL || element->type != E820_TYPE_MEMORY || 210 (base < element->base || end > element->end)) 211 return (ENOMEM); 212 213 if (base == element->base) { 214 /* 215 * New element at system memory base boundary. Add new 216 * element before current and adjust the base of the old 217 * element. 218 * 219 * Old table: 220 * [ 0x1000, 0x4000] RAM <-- element 221 * New table: 222 * [ 0x1000, 0x2000] Reserved 223 * [ 0x2000, 0x4000] RAM <-- element 224 */ 225 TAILQ_INSERT_BEFORE(element, new_element, chain); 226 element->base = end; 227 } else if (end == element->end) { 228 /* 229 * New element at system memory end boundary. Add new 230 * element after current and adjust the end of the 231 * current element. 232 * 233 * Old table: 234 * [ 0x1000, 0x4000] RAM <-- element 235 * New table: 236 * [ 0x1000, 0x3000] RAM <-- element 237 * [ 0x3000, 0x4000] Reserved 238 */ 239 TAILQ_INSERT_AFTER(&e820_table, element, new_element, chain); 240 element->end = base; 241 } else { 242 /* 243 * New element inside system memory entry. Split it by 244 * adding a system memory element and the new element 245 * before current. 246 * 247 * Old table: 248 * [ 0x1000, 0x4000] RAM <-- element 249 * New table: 250 * [ 0x1000, 0x2000] RAM 251 * [ 0x2000, 0x3000] Reserved 252 * [ 0x3000, 0x4000] RAM <-- element 253 */ 254 ram_element = e820_element_alloc(element->base, base, 255 E820_TYPE_MEMORY); 256 if (ram_element == NULL) { 257 return (ENOMEM); 258 } 259 TAILQ_INSERT_BEFORE(element, ram_element, chain); 260 TAILQ_INSERT_BEFORE(element, new_element, chain); 261 element->base = end; 262 } 263 264 return (0); 265 } 266 267 static int 268 e820_add_memory_hole(const uint64_t base, const uint64_t end) 269 { 270 struct e820_element *element; 271 struct e820_element *ram_element; 272 273 assert(end >= base); 274 275 /* 276 * E820 table should be always sorted in ascending order. Therefore, 277 * search for an element which end is larger than the base parameter. 278 */ 279 TAILQ_FOREACH(element, &e820_table, chain) { 280 if (element->end > base) { 281 break; 282 } 283 } 284 285 if (element == NULL || end <= element->base) { 286 /* Nothing to do. Hole already exists */ 287 return (0); 288 } 289 290 /* Memory holes are only allowed in system memory */ 291 assert(element->type == E820_TYPE_MEMORY); 292 293 if (base == element->base) { 294 /* 295 * New hole at system memory base boundary. 296 * 297 * Old table: 298 * [ 0x1000, 0x4000] RAM 299 * New table: 300 * [ 0x2000, 0x4000] RAM 301 */ 302 element->base = end; 303 } else if (end == element->end) { 304 /* 305 * New hole at system memory end boundary. 306 * 307 * Old table: 308 * [ 0x1000, 0x4000] RAM 309 * New table: 310 * [ 0x1000, 0x3000] RAM 311 */ 312 element->end = base; 313 } else { 314 /* 315 * New hole inside system memory entry. Split the system memory. 316 * 317 * Old table: 318 * [ 0x1000, 0x4000] RAM <-- element 319 * New table: 320 * [ 0x1000, 0x2000] RAM 321 * [ 0x3000, 0x4000] RAM <-- element 322 */ 323 ram_element = e820_element_alloc(element->base, base, 324 E820_TYPE_MEMORY); 325 if (ram_element == NULL) { 326 return (ENOMEM); 327 } 328 TAILQ_INSERT_BEFORE(element, ram_element, chain); 329 element->base = end; 330 } 331 332 return (0); 333 } 334 335 static uint64_t 336 e820_alloc_highest(const uint64_t max_address, const uint64_t length, 337 const uint64_t alignment, const enum e820_memory_type type) 338 { 339 struct e820_element *element; 340 341 TAILQ_FOREACH_REVERSE(element, &e820_table, e820_table, chain) { 342 uint64_t address, base, end; 343 344 end = MIN(max_address, element->end); 345 base = roundup2(element->base, alignment); 346 347 /* 348 * If end - length == 0, we would allocate memory at address 0. This 349 * address is mostly unusable and we should avoid allocating it. 350 * Therefore, search for another block in that case. 351 */ 352 if (element->type != E820_TYPE_MEMORY || end < base || 353 end - base < length || end - length == 0) { 354 continue; 355 } 356 357 address = rounddown2(end - length, alignment); 358 359 if (e820_add_entry(address, address + length, type) != 0) { 360 return (0); 361 } 362 363 return (address); 364 } 365 366 return (0); 367 } 368 369 static uint64_t 370 e820_alloc_lowest(const uint64_t min_address, const uint64_t length, 371 const uint64_t alignment, const enum e820_memory_type type) 372 { 373 struct e820_element *element; 374 375 TAILQ_FOREACH(element, &e820_table, chain) { 376 uint64_t base, end; 377 378 end = element->end; 379 base = MAX(min_address, roundup2(element->base, alignment)); 380 381 /* 382 * If base == 0, we would allocate memory at address 0. This 383 * address is mostly unusable and we should avoid allocating it. 384 * Therefore, search for another block in that case. 385 */ 386 if (element->type != E820_TYPE_MEMORY || end < base || 387 end - base < length || base == 0) { 388 continue; 389 } 390 391 if (e820_add_entry(base, base + length, type) != 0) { 392 return (0); 393 } 394 395 return (base); 396 } 397 398 return (0); 399 } 400 401 uint64_t 402 e820_alloc(const uint64_t address, const uint64_t length, 403 const uint64_t alignment, const enum e820_memory_type type, 404 const enum e820_allocation_strategy strategy) 405 { 406 assert(powerof2(alignment)); 407 assert((address & (alignment - 1)) == 0); 408 409 switch (strategy) { 410 case E820_ALLOCATE_ANY: 411 /* 412 * Allocate any address. Therefore, ignore the address parameter 413 * and reuse the code path for allocating the lowest address. 414 */ 415 return (e820_alloc_lowest(0, length, alignment, type)); 416 case E820_ALLOCATE_LOWEST: 417 return (e820_alloc_lowest(address, length, alignment, type)); 418 case E820_ALLOCATE_HIGHEST: 419 return (e820_alloc_highest(address, length, alignment, type)); 420 case E820_ALLOCATE_SPECIFIC: 421 if (e820_add_entry(address, address + length, type) != 0) { 422 return (0); 423 } 424 425 return (address); 426 } 427 428 return (0); 429 } 430 431 int 432 e820_init(struct vmctx *const ctx) 433 { 434 uint64_t lowmem_size, highmem_size; 435 int error; 436 437 TAILQ_INIT(&e820_table); 438 439 lowmem_size = vm_get_lowmem_size(ctx); 440 error = e820_add_entry(0, lowmem_size, E820_TYPE_MEMORY); 441 if (error) { 442 warnx("%s: Could not add lowmem", __func__); 443 return (error); 444 } 445 446 highmem_size = vm_get_highmem_size(ctx); 447 if (highmem_size != 0) { 448 error = e820_add_entry(4 * GB, 4 * GB + highmem_size, 449 E820_TYPE_MEMORY); 450 if (error) { 451 warnx("%s: Could not add highmem", __func__); 452 return (error); 453 } 454 } 455 456 error = e820_add_memory_hole(E820_VGA_MEM_BASE, E820_VGA_MEM_END); 457 if (error) { 458 warnx("%s: Could not add VGA memory", __func__); 459 return (error); 460 } 461 462 error = e820_add_memory_hole(E820_ROM_MEM_BASE, E820_ROM_MEM_END); 463 if (error) { 464 warnx("%s: Could not add ROM area", __func__); 465 return (error); 466 } 467 468 return (0); 469 } 470 471 int 472 e820_finalize(void) 473 { 474 struct qemu_fwcfg_item *e820_fwcfg_item; 475 int error; 476 477 e820_fwcfg_item = e820_get_fwcfg_item(); 478 if (e820_fwcfg_item == NULL) { 479 warnx("invalid e820 table"); 480 return (ENOMEM); 481 } 482 error = qemu_fwcfg_add_file("etc/e820", 483 e820_fwcfg_item->size, e820_fwcfg_item->data); 484 if (error != 0) { 485 warnx("could not add qemu fwcfg etc/e820"); 486 free(e820_fwcfg_item->data); 487 free(e820_fwcfg_item); 488 return (error); 489 } 490 free(e820_fwcfg_item); 491 492 return (0); 493 } 494