arch/x86/xen/setup.c

   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 }