1 /* 2 * Machine specific setup for xen 3 * 4 * Jeremy Fitzhardinge <jeremy@xensource.com>, XenSource Inc, 2007 5 */ 6 7 #include <linux/module.h> 8 #include <linux/sched.h> 9 #include <linux/mm.h> 10 #include <linux/pm.h> 11 #include <linux/memblock.h> 12 #include <linux/cpuidle.h> 13 #include <linux/cpufreq.h> 14 15 #include <asm/elf.h> 16 #include <asm/vdso.h> 17 #include <asm/e820.h> 18 #include <asm/setup.h> 19 #include <asm/acpi.h> 20 #include <asm/xen/hypervisor.h> 21 #include <asm/xen/hypercall.h> 22 23 #include <xen/xen.h> 24 #include <xen/page.h> 25 #include <xen/interface/callback.h> 26 #include <xen/interface/memory.h> 27 #include <xen/interface/physdev.h> 28 #include <xen/features.h> 29 #include "xen-ops.h" 30 #include "vdso.h" 31 32 /* These are code, but not functions. Defined in entry.S */ 33 extern const char xen_hypervisor_callback[]; 34 extern const char xen_failsafe_callback[]; 35 extern void xen_sysenter_target(void); 36 extern void xen_syscall_target(void); 37 extern void xen_syscall32_target(void); 38 39 /* Amount of extra memory space we add to the e820 ranges */ 40 struct xen_memory_region xen_extra_mem[XEN_EXTRA_MEM_MAX_REGIONS] __initdata; 41 42 /* Number of pages released from the initial allocation. */ 43 unsigned long xen_released_pages; 44 45 /* 46 * The maximum amount of extra memory compared to the base size. The 47 * main scaling factor is the size of struct page. At extreme ratios 48 * of base:extra, all the base memory can be filled with page 49 * structures for the extra memory, leaving no space for anything 50 * else. 51 * 52 * 10x seems like a reasonable balance between scaling flexibility and 53 * leaving a practically usable system. 54 */ 55 #define EXTRA_MEM_RATIO (10) 56 57 static void __init xen_add_extra_mem(u64 start, u64 size) 58 { 59 unsigned long pfn; 60 int i; 61 62 for (i = 0; i < XEN_EXTRA_MEM_MAX_REGIONS; i++) { 63 /* Add new region. */ 64 if (xen_extra_mem[i].size == 0) { 65 xen_extra_mem[i].start = start; 66 xen_extra_mem[i].size = size; 67 break; 68 } 69 /* Append to existing region. */ 70 if (xen_extra_mem[i].start + xen_extra_mem[i].size == start) { 71 xen_extra_mem[i].size += size; 72 break; 73 } 74 } 75 if (i == XEN_EXTRA_MEM_MAX_REGIONS) 76 printk(KERN_WARNING "Warning: not enough extra memory regions\n"); 77 78 memblock_reserve(start, size); 79 80 xen_max_p2m_pfn = PFN_DOWN(start + size); 81 for (pfn = PFN_DOWN(start); pfn < xen_max_p2m_pfn; pfn++) { 82 unsigned long mfn = pfn_to_mfn(pfn); 83 84 if (WARN(mfn == pfn, "Trying to over-write 1-1 mapping (pfn: %lx)\n", pfn)) 85 continue; 86 WARN(mfn != INVALID_P2M_ENTRY, "Trying to remove %lx which has %lx mfn!\n", 87 pfn, mfn); 88 89 __set_phys_to_machine(pfn, INVALID_P2M_ENTRY); 90 } 91 } 92 93 static unsigned long __init xen_do_chunk(unsigned long start, 94 unsigned long end, bool release) 95 { 96 struct xen_memory_reservation reservation = { 97 .address_bits = 0, 98 .extent_order = 0, 99 .domid = DOMID_SELF 100 }; 101 unsigned long len = 0; 102 unsigned long pfn; 103 int ret; 104 105 for (pfn = start; pfn < end; pfn++) { 106 unsigned long frame; 107 unsigned long mfn = pfn_to_mfn(pfn); 108 109 if (release) { 110 /* Make sure pfn exists to start with */ 111 if (mfn == INVALID_P2M_ENTRY || mfn_to_pfn(mfn) != pfn) 112 continue; 113 frame = mfn; 114 } else { 115 if (mfn != INVALID_P2M_ENTRY) 116 continue; 117 frame = pfn; 118 } 119 set_xen_guest_handle(reservation.extent_start, &frame); 120 reservation.nr_extents = 1; 121 122 ret = HYPERVISOR_memory_op(release ? XENMEM_decrease_reservation : XENMEM_populate_physmap, 123 &reservation); 124 WARN(ret != 1, "Failed to %s pfn %lx err=%d\n", 125 release ? "release" : "populate", pfn, ret); 126 127 if (ret == 1) { 128 if (!early_set_phys_to_machine(pfn, release ? INVALID_P2M_ENTRY : frame)) { 129 if (release) 130 break; 131 set_xen_guest_handle(reservation.extent_start, &frame); 132 reservation.nr_extents = 1; 133 ret = HYPERVISOR_memory_op(XENMEM_decrease_reservation, 134 &reservation); 135 break; 136 } 137 len++; 138 } else 139 break; 140 } 141 if (len) 142 printk(KERN_INFO "%s %lx-%lx pfn range: %lu pages %s\n", 143 release ? "Freeing" : "Populating", 144 start, end, len, 145 release ? "freed" : "added"); 146 147 return len; 148 } 149 150 static unsigned long __init xen_release_chunk(unsigned long start, 151 unsigned long end) 152 { 153 return xen_do_chunk(start, end, true); 154 } 155 156 static unsigned long __init xen_populate_chunk( 157 const struct e820entry *list, size_t map_size, 158 unsigned long max_pfn, unsigned long *last_pfn, 159 unsigned long credits_left) 160 { 161 const struct e820entry *entry; 162 unsigned int i; 163 unsigned long done = 0; 164 unsigned long dest_pfn; 165 166 for (i = 0, entry = list; i < map_size; i++, entry++) { 167 unsigned long s_pfn; 168 unsigned long e_pfn; 169 unsigned long pfns; 170 long capacity; 171 172 if (credits_left <= 0) 173 break; 174 175 if (entry->type != E820_RAM) 176 continue; 177 178 e_pfn = PFN_DOWN(entry->addr + entry->size); 179 180 /* We only care about E820 after the xen_start_info->nr_pages */ 181 if (e_pfn <= max_pfn) 182 continue; 183 184 s_pfn = PFN_UP(entry->addr); 185 /* If the E820 falls within the nr_pages, we want to start 186 * at the nr_pages PFN. 187 * If that would mean going past the E820 entry, skip it 188 */ 189 if (s_pfn <= max_pfn) { 190 capacity = e_pfn - max_pfn; 191 dest_pfn = max_pfn; 192 } else { 193 capacity = e_pfn - s_pfn; 194 dest_pfn = s_pfn; 195 } 196 197 if (credits_left < capacity) 198 capacity = credits_left; 199 200 pfns = xen_do_chunk(dest_pfn, dest_pfn + capacity, false); 201 done += pfns; 202 *last_pfn = (dest_pfn + pfns); 203 if (pfns < capacity) 204 break; 205 credits_left -= pfns; 206 } 207 return done; 208 } 209 210 static void __init xen_set_identity_and_release_chunk( 211 unsigned long start_pfn, unsigned long end_pfn, unsigned long nr_pages, 212 unsigned long *released, unsigned long *identity) 213 { 214 unsigned long pfn; 215 216 /* 217 * If the PFNs are currently mapped, the VA mapping also needs 218 * to be updated to be 1:1. 219 */ 220 for (pfn = start_pfn; pfn <= max_pfn_mapped && pfn < end_pfn; pfn++) 221 (void)HYPERVISOR_update_va_mapping( 222 (unsigned long)__va(pfn << PAGE_SHIFT), 223 mfn_pte(pfn, PAGE_KERNEL_IO), 0); 224 225 if (start_pfn < nr_pages) 226 *released += xen_release_chunk( 227 start_pfn, min(end_pfn, nr_pages)); 228 229 *identity += set_phys_range_identity(start_pfn, end_pfn); 230 } 231 232 static unsigned long __init xen_set_identity_and_release( 233 const struct e820entry *list, size_t map_size, unsigned long nr_pages) 234 { 235 phys_addr_t start = 0; 236 unsigned long released = 0; 237 unsigned long identity = 0; 238 const struct e820entry *entry; 239 int i; 240 241 /* 242 * Combine non-RAM regions and gaps until a RAM region (or the 243 * end of the map) is reached, then set the 1:1 map and 244 * release the pages (if available) in those non-RAM regions. 245 * 246 * The combined non-RAM regions are rounded to a whole number 247 * of pages so any partial pages are accessible via the 1:1 248 * mapping. This is needed for some BIOSes that put (for 249 * example) the DMI tables in a reserved region that begins on 250 * a non-page boundary. 251 */ 252 for (i = 0, entry = list; i < map_size; i++, entry++) { 253 phys_addr_t end = entry->addr + entry->size; 254 if (entry->type == E820_RAM || i == map_size - 1) { 255 unsigned long start_pfn = PFN_DOWN(start); 256 unsigned long end_pfn = PFN_UP(end); 257 258 if (entry->type == E820_RAM) 259 end_pfn = PFN_UP(entry->addr); 260 261 if (start_pfn < end_pfn) 262 xen_set_identity_and_release_chunk( 263 start_pfn, end_pfn, nr_pages, 264 &released, &identity); 265 266 start = end; 267 } 268 } 269 270 if (released) 271 printk(KERN_INFO "Released %lu pages of unused memory\n", released); 272 if (identity) 273 printk(KERN_INFO "Set %ld page(s) to 1-1 mapping\n", identity); 274 275 return released; 276 } 277 278 static unsigned long __init xen_get_max_pages(void) 279 { 280 unsigned long max_pages = MAX_DOMAIN_PAGES; 281 domid_t domid = DOMID_SELF; 282 int ret; 283 284 /* 285 * For the initial domain we use the maximum reservation as 286 * the maximum page. 287 * 288 * For guest domains the current maximum reservation reflects 289 * the current maximum rather than the static maximum. In this 290 * case the e820 map provided to us will cover the static 291 * maximum region. 292 */ 293 if (xen_initial_domain()) { 294 ret = HYPERVISOR_memory_op(XENMEM_maximum_reservation, &domid); 295 if (ret > 0) 296 max_pages = ret; 297 } 298 299 return min(max_pages, MAX_DOMAIN_PAGES); 300 } 301 302 static void xen_align_and_add_e820_region(u64 start, u64 size, int type) 303 { 304 u64 end = start + size; 305 306 /* Align RAM regions to page boundaries. */ 307 if (type == E820_RAM) { 308 start = PAGE_ALIGN(start); 309 end &= ~((u64)PAGE_SIZE - 1); 310 } 311 312 e820_add_region(start, end - start, type); 313 } 314 315 /** 316 * machine_specific_memory_setup - Hook for machine specific memory setup. 317 **/ 318 char * __init xen_memory_setup(void) 319 { 320 static struct e820entry map[E820MAX] __initdata; 321 322 unsigned long max_pfn = xen_start_info->nr_pages; 323 unsigned long long mem_end; 324 int rc; 325 struct xen_memory_map memmap; 326 unsigned long max_pages; 327 unsigned long last_pfn = 0; 328 unsigned long extra_pages = 0; 329 unsigned long populated; 330 int i; 331 int op; 332 333 max_pfn = min(MAX_DOMAIN_PAGES, max_pfn); 334 mem_end = PFN_PHYS(max_pfn); 335 336 memmap.nr_entries = E820MAX; 337 set_xen_guest_handle(memmap.buffer, map); 338 339 op = xen_initial_domain() ? 340 XENMEM_machine_memory_map : 341 XENMEM_memory_map; 342 rc = HYPERVISOR_memory_op(op, &memmap); 343 if (rc == -ENOSYS) { 344 BUG_ON(xen_initial_domain()); 345 memmap.nr_entries = 1; 346 map[0].addr = 0ULL; 347 map[0].size = mem_end; 348 /* 8MB slack (to balance backend allocations). */ 349 map[0].size += 8ULL << 20; 350 map[0].type = E820_RAM; 351 rc = 0; 352 } 353 BUG_ON(rc); 354 355 /* Make sure the Xen-supplied memory map is well-ordered. */ 356 sanitize_e820_map(map, memmap.nr_entries, &memmap.nr_entries); 357 358 max_pages = xen_get_max_pages(); 359 if (max_pages > max_pfn) 360 extra_pages += max_pages - max_pfn; 361 362 /* 363 * Set P2M for all non-RAM pages and E820 gaps to be identity 364 * type PFNs. Any RAM pages that would be made inaccesible by 365 * this are first released. 366 */ 367 xen_released_pages = xen_set_identity_and_release( 368 map, memmap.nr_entries, max_pfn); 369 370 /* 371 * Populate back the non-RAM pages and E820 gaps that had been 372 * released. */ 373 populated = xen_populate_chunk(map, memmap.nr_entries, 374 max_pfn, &last_pfn, xen_released_pages); 375 376 xen_released_pages -= populated; 377 extra_pages += xen_released_pages; 378 379 if (last_pfn > max_pfn) { 380 max_pfn = min(MAX_DOMAIN_PAGES, last_pfn); 381 mem_end = PFN_PHYS(max_pfn); 382 } 383 /* 384 * Clamp the amount of extra memory to a EXTRA_MEM_RATIO 385 * factor the base size. On non-highmem systems, the base 386 * size is the full initial memory allocation; on highmem it 387 * is limited to the max size of lowmem, so that it doesn't 388 * get completely filled. 389 * 390 * In principle there could be a problem in lowmem systems if 391 * the initial memory is also very large with respect to 392 * lowmem, but we won't try to deal with that here. 393 */ 394 extra_pages = min(EXTRA_MEM_RATIO * min(max_pfn, PFN_DOWN(MAXMEM)), 395 extra_pages); 396 i = 0; 397 while (i < memmap.nr_entries) { 398 u64 addr = map[i].addr; 399 u64 size = map[i].size; 400 u32 type = map[i].type; 401 402 if (type == E820_RAM) { 403 if (addr < mem_end) { 404 size = min(size, mem_end - addr); 405 } else if (extra_pages) { 406 size = min(size, (u64)extra_pages * PAGE_SIZE); 407 extra_pages -= size / PAGE_SIZE; 408 xen_add_extra_mem(addr, size); 409 } else 410 type = E820_UNUSABLE; 411 } 412 413 xen_align_and_add_e820_region(addr, size, type); 414 415 map[i].addr += size; 416 map[i].size -= size; 417 if (map[i].size == 0) 418 i++; 419 } 420 421 /* 422 * In domU, the ISA region is normal, usable memory, but we 423 * reserve ISA memory anyway because too many things poke 424 * about in there. 425 */ 426 e820_add_region(ISA_START_ADDRESS, ISA_END_ADDRESS - ISA_START_ADDRESS, 427 E820_RESERVED); 428 429 /* 430 * Reserve Xen bits: 431 * - mfn_list 432 * - xen_start_info 433 * See comment above "struct start_info" in <xen/interface/xen.h> 434 */ 435 memblock_reserve(__pa(xen_start_info->mfn_list), 436 xen_start_info->pt_base - xen_start_info->mfn_list); 437 438 sanitize_e820_map(e820.map, ARRAY_SIZE(e820.map), &e820.nr_map); 439 440 return "Xen"; 441 } 442 443 /* 444 * Set the bit indicating "nosegneg" library variants should be used. 445 * We only need to bother in pure 32-bit mode; compat 32-bit processes 446 * can have un-truncated segments, so wrapping around is allowed. 447 */ 448 static void __init fiddle_vdso(void) 449 { 450 #ifdef CONFIG_X86_32 451 u32 *mask; 452 mask = VDSO32_SYMBOL(&vdso32_int80_start, NOTE_MASK); 453 *mask |= 1 << VDSO_NOTE_NONEGSEG_BIT; 454 mask = VDSO32_SYMBOL(&vdso32_sysenter_start, NOTE_MASK); 455 *mask |= 1 << VDSO_NOTE_NONEGSEG_BIT; 456 #endif 457 } 458 459 static int __cpuinit register_callback(unsigned type, const void *func) 460 { 461 struct callback_register callback = { 462 .type = type, 463 .address = XEN_CALLBACK(__KERNEL_CS, func), 464 .flags = CALLBACKF_mask_events, 465 }; 466 467 return HYPERVISOR_callback_op(CALLBACKOP_register, &callback); 468 } 469 470 void __cpuinit xen_enable_sysenter(void) 471 { 472 int ret; 473 unsigned sysenter_feature; 474 475 #ifdef CONFIG_X86_32 476 sysenter_feature = X86_FEATURE_SEP; 477 #else 478 sysenter_feature = X86_FEATURE_SYSENTER32; 479 #endif 480 481 if (!boot_cpu_has(sysenter_feature)) 482 return; 483 484 ret = register_callback(CALLBACKTYPE_sysenter, xen_sysenter_target); 485 if(ret != 0) 486 setup_clear_cpu_cap(sysenter_feature); 487 } 488 489 void __cpuinit xen_enable_syscall(void) 490 { 491 #ifdef CONFIG_X86_64 492 int ret; 493 494 ret = register_callback(CALLBACKTYPE_syscall, xen_syscall_target); 495 if (ret != 0) { 496 printk(KERN_ERR "Failed to set syscall callback: %d\n", ret); 497 /* Pretty fatal; 64-bit userspace has no other 498 mechanism for syscalls. */ 499 } 500 501 if (boot_cpu_has(X86_FEATURE_SYSCALL32)) { 502 ret = register_callback(CALLBACKTYPE_syscall32, 503 xen_syscall32_target); 504 if (ret != 0) 505 setup_clear_cpu_cap(X86_FEATURE_SYSCALL32); 506 } 507 #endif /* CONFIG_X86_64 */ 508 } 509 510 void __init xen_arch_setup(void) 511 { 512 xen_panic_handler_init(); 513 514 HYPERVISOR_vm_assist(VMASST_CMD_enable, VMASST_TYPE_4gb_segments); 515 HYPERVISOR_vm_assist(VMASST_CMD_enable, VMASST_TYPE_writable_pagetables); 516 517 if (!xen_feature(XENFEAT_auto_translated_physmap)) 518 HYPERVISOR_vm_assist(VMASST_CMD_enable, 519 VMASST_TYPE_pae_extended_cr3); 520 521 if (register_callback(CALLBACKTYPE_event, xen_hypervisor_callback) || 522 register_callback(CALLBACKTYPE_failsafe, xen_failsafe_callback)) 523 BUG(); 524 525 xen_enable_sysenter(); 526 xen_enable_syscall(); 527 528 #ifdef CONFIG_ACPI 529 if (!(xen_start_info->flags & SIF_INITDOMAIN)) { 530 printk(KERN_INFO "ACPI in unprivileged domain disabled\n"); 531 disable_acpi(); 532 } 533 #endif 534 535 memcpy(boot_command_line, xen_start_info->cmd_line, 536 MAX_GUEST_CMDLINE > COMMAND_LINE_SIZE ? 537 COMMAND_LINE_SIZE : MAX_GUEST_CMDLINE); 538 539 /* Set up idle, making sure it calls safe_halt() pvop */ 540 #ifdef CONFIG_X86_32 541 boot_cpu_data.hlt_works_ok = 1; 542 #endif 543 disable_cpuidle(); 544 disable_cpufreq(); 545 WARN_ON(set_pm_idle_to_default()); 546 fiddle_vdso(); 547 } 548