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/numa.h>
  21 #include <asm/xen/hypervisor.h>
  22 #include <asm/xen/hypercall.h>
  23
  24 #include <xen/xen.h>
  25 #include <xen/page.h>
  26 #include <xen/interface/callback.h>
  27 #include <xen/interface/memory.h>
  28 #include <xen/interface/physdev.h>
  29 #include <xen/features.h>
  30 #include "xen-ops.h"
  31 #include "vdso.h"
  32
  33 /* These are code, but not functions.  Defined in entry.S */
  34 extern const char xen_hypervisor_callback[];
  35 extern const char xen_failsafe_callback[];
  36 extern void xen_sysenter_target(void);
  37 extern void xen_syscall_target(void);
  38 extern void xen_syscall32_target(void);
  39
  40 /* Amount of extra memory space we add to the e820 ranges */
  41 struct xen_memory_region xen_extra_mem[XEN_EXTRA_MEM_MAX_REGIONS] __initdata;
  42
  43 /* Number of pages released from the initial allocation. */
  44 unsigned long xen_released_pages;
  45
  46 /*
  47  * The maximum amount of extra memory compared to the base size.  The
  48  * main scaling factor is the size of struct page.  At extreme ratios
  49  * of base:extra, all the base memory can be filled with page
  50  * structures for the extra memory, leaving no space for anything
  51  * else.
  52  *
  53  * 10x seems like a reasonable balance between scaling flexibility and
  54  * leaving a practically usable system.
  55  */
  56 #define EXTRA_MEM_RATIO         (10)
  57
  58 static void __init xen_add_extra_mem(u64 start, u64 size)
  59 {
  60         unsigned long pfn;
  61         int i;
  62
  63         for (i = 0; i < XEN_EXTRA_MEM_MAX_REGIONS; i++) {
  64                 /* Add new region. */
  65                 if (xen_extra_mem[i].size == 0) {
  66                         xen_extra_mem[i].start = start;
  67                         xen_extra_mem[i].size  = size;
  68                         break;
  69                 }
  70                 /* Append to existing region. */
  71                 if (xen_extra_mem[i].start + xen_extra_mem[i].size == start) {
  72                         xen_extra_mem[i].size += size;
  73                         break;
  74                 }
  75         }
  76         if (i == XEN_EXTRA_MEM_MAX_REGIONS)
  77                 printk(KERN_WARNING "Warning: not enough extra memory regions\n");
  78
  79         memblock_reserve(start, size);
  80
  81         xen_max_p2m_pfn = PFN_DOWN(start + size);
  82         for (pfn = PFN_DOWN(start); pfn < xen_max_p2m_pfn; pfn++) {
  83                 unsigned long mfn = pfn_to_mfn(pfn);
  84
  85                 if (WARN(mfn == pfn, "Trying to over-write 1-1 mapping (pfn: %lx)\n", pfn))
  86                         continue;
  87                 WARN(mfn != INVALID_P2M_ENTRY, "Trying to remove %lx which has %lx mfn!\n",
  88                         pfn, mfn);
  89
  90                 __set_phys_to_machine(pfn, INVALID_P2M_ENTRY);
  91         }
  92 }
  93
  94 static unsigned long __init xen_do_chunk(unsigned long start,
  95                                          unsigned long end, bool release)
  96 {
  97         struct xen_memory_reservation reservation = {
  98                 .address_bits = 0,
  99                 .extent_order = 0,
 100                 .domid        = DOMID_SELF
 101         };
 102         unsigned long len = 0;
 103         unsigned long pfn;
 104         int ret;
 105
 106         for (pfn = start; pfn < end; pfn++) {
 107                 unsigned long frame;
 108                 unsigned long mfn = pfn_to_mfn(pfn);
 109
 110                 if (release) {
 111                         /* Make sure pfn exists to start with */
 112                         if (mfn == INVALID_P2M_ENTRY || mfn_to_pfn(mfn) != pfn)
 113                                 continue;
 114                         frame = mfn;
 115                 } else {
 116                         if (mfn != INVALID_P2M_ENTRY)
 117                                 continue;
 118                         frame = pfn;
 119                 }
 120                 set_xen_guest_handle(reservation.extent_start, &frame);
 121                 reservation.nr_extents = 1;
 122
 123                 ret = HYPERVISOR_memory_op(release ? XENMEM_decrease_reservation : XENMEM_populate_physmap,
 124                                            &reservation);
 125                 WARN(ret != 1, "Failed to %s pfn %lx err=%d\n",
 126                      release ? "release" : "populate", pfn, ret);
 127
 128                 if (ret == 1) {
 129                         if (!early_set_phys_to_machine(pfn, release ? INVALID_P2M_ENTRY : frame)) {
 130                                 if (release)
 131                                         break;
 132                                 set_xen_guest_handle(reservation.extent_start, &frame);
 133                                 reservation.nr_extents = 1;
 134                                 ret = HYPERVISOR_memory_op(XENMEM_decrease_reservation,
 135                                                            &reservation);
 136                                 break;
 137                         }
 138                         len++;
 139                 } else
 140                         break;
 141         }
 142         if (len)
 143                 printk(KERN_INFO "%s %lx-%lx pfn range: %lu pages %s\n",
 144                        release ? "Freeing" : "Populating",
 145                        start, end, len,
 146                        release ? "freed" : "added");
 147
 148         return len;
 149 }
 150
 151 static unsigned long __init xen_release_chunk(unsigned long start,
 152                                               unsigned long end)
 153 {
 154         return xen_do_chunk(start, end, true);
 155 }
 156
 157 static unsigned long __init xen_populate_chunk(
 158         const struct e820entry *list, size_t map_size,
 159         unsigned long max_pfn, unsigned long *last_pfn,
 160         unsigned long credits_left)
 161 {
 162         const struct e820entry *entry;
 163         unsigned int i;
 164         unsigned long done = 0;
 165         unsigned long dest_pfn;
 166
 167         for (i = 0, entry = list; i < map_size; i++, entry++) {
 168                 unsigned long s_pfn;
 169                 unsigned long e_pfn;
 170                 unsigned long pfns;
 171                 long capacity;
 172
 173                 if (credits_left <= 0)
 174                         break;
 175
 176                 if (entry->type != E820_RAM)
 177                         continue;
 178
 179                 e_pfn = PFN_DOWN(entry->addr + entry->size);
 180
 181                 /* We only care about E820 after the xen_start_info->nr_pages */
 182                 if (e_pfn <= max_pfn)
 183                         continue;
 184
 185                 s_pfn = PFN_UP(entry->addr);
 186                 /* If the E820 falls within the nr_pages, we want to start
 187                  * at the nr_pages PFN.
 188                  * If that would mean going past the E820 entry, skip it
 189                  */
 190                 if (s_pfn <= max_pfn) {
 191                         capacity = e_pfn - max_pfn;
 192                         dest_pfn = max_pfn;
 193                 } else {
 194                         capacity = e_pfn - s_pfn;
 195                         dest_pfn = s_pfn;
 196                 }
 197
 198                 if (credits_left < capacity)
 199                         capacity = credits_left;
 200
 201                 pfns = xen_do_chunk(dest_pfn, dest_pfn + capacity, false);
 202                 done += pfns;
 203                 *last_pfn = (dest_pfn + pfns);
 204                 if (pfns < capacity)
 205                         break;
 206                 credits_left -= pfns;
 207         }
 208         return done;
 209 }
 210
 211 static void __init xen_set_identity_and_release_chunk(
 212         unsigned long start_pfn, unsigned long end_pfn, unsigned long nr_pages,
 213         unsigned long *released, unsigned long *identity)
 214 {
 215         unsigned long pfn;
 216
 217         /*
 218          * If the PFNs are currently mapped, the VA mapping also needs
 219          * to be updated to be 1:1.
 220          */
 221         for (pfn = start_pfn; pfn <= max_pfn_mapped && pfn < end_pfn; pfn++)
 222                 (void)HYPERVISOR_update_va_mapping(
 223                         (unsigned long)__va(pfn << PAGE_SHIFT),
 224                         mfn_pte(pfn, PAGE_KERNEL_IO), 0);
 225
 226         if (start_pfn < nr_pages)
 227                 *released += xen_release_chunk(
 228                         start_pfn, min(end_pfn, nr_pages));
 229
 230         *identity += set_phys_range_identity(start_pfn, end_pfn);
 231 }
 232
 233 static unsigned long __init xen_set_identity_and_release(
 234         const struct e820entry *list, size_t map_size, unsigned long nr_pages)
 235 {
 236         phys_addr_t start = 0;
 237         unsigned long released = 0;
 238         unsigned long identity = 0;
 239         const struct e820entry *entry;
 240         int i;
 241
 242         /*
 243          * Combine non-RAM regions and gaps until a RAM region (or the
 244          * end of the map) is reached, then set the 1:1 map and
 245          * release the pages (if available) in those non-RAM regions.
 246          *
 247          * The combined non-RAM regions are rounded to a whole number
 248          * of pages so any partial pages are accessible via the 1:1
 249          * mapping.  This is needed for some BIOSes that put (for
 250          * example) the DMI tables in a reserved region that begins on
 251          * a non-page boundary.
 252          */
 253         for (i = 0, entry = list; i < map_size; i++, entry++) {
 254                 phys_addr_t end = entry->addr + entry->size;
 255                 if (entry->type == E820_RAM || i == map_size - 1) {
 256                         unsigned long start_pfn = PFN_DOWN(start);
 257                         unsigned long end_pfn = PFN_UP(end);
 258
 259                         if (entry->type == E820_RAM)
 260                                 end_pfn = PFN_UP(entry->addr);
 261
 262                         if (start_pfn < end_pfn)
 263                                 xen_set_identity_and_release_chunk(
 264                                         start_pfn, end_pfn, nr_pages,
 265                                         &released, &identity);
 266
 267                         start = end;
 268                 }
 269         }
 270
 271         if (released)
 272                 printk(KERN_INFO "Released %lu pages of unused memory\n", released);
 273         if (identity)
 274                 printk(KERN_INFO "Set %ld page(s) to 1-1 mapping\n", identity);
 275
 276         return released;
 277 }
 278
 279 static unsigned long __init xen_get_max_pages(void)
 280 {
 281         unsigned long max_pages = MAX_DOMAIN_PAGES;
 282         domid_t domid = DOMID_SELF;
 283         int ret;
 284
 285         /*
 286          * For the initial domain we use the maximum reservation as
 287          * the maximum page.
 288          *
 289          * For guest domains the current maximum reservation reflects
 290          * the current maximum rather than the static maximum. In this
 291          * case the e820 map provided to us will cover the static
 292          * maximum region.
 293          */
 294         if (xen_initial_domain()) {
 295                 ret = HYPERVISOR_memory_op(XENMEM_maximum_reservation, &domid);
 296                 if (ret > 0)
 297                         max_pages = ret;
 298         }
 299
 300         return min(max_pages, MAX_DOMAIN_PAGES);
 301 }
 302
 303 static void xen_align_and_add_e820_region(u64 start, u64 size, int type)
 304 {
 305         u64 end = start + size;
 306
 307         /* Align RAM regions to page boundaries. */
 308         if (type == E820_RAM) {
 309                 start = PAGE_ALIGN(start);
 310                 end &= ~((u64)PAGE_SIZE - 1);
 311         }
 312
 313         e820_add_region(start, end - start, type);
 314 }
 315
 316 /**
 317  * machine_specific_memory_setup - Hook for machine specific memory setup.
 318  **/
 319 char * __init xen_memory_setup(void)
 320 {
 321         static struct e820entry map[E820MAX] __initdata;
 322
 323         unsigned long max_pfn = xen_start_info->nr_pages;
 324         unsigned long long mem_end;
 325         int rc;
 326         struct xen_memory_map memmap;
 327         unsigned long max_pages;
 328         unsigned long last_pfn = 0;
 329         unsigned long extra_pages = 0;
 330         unsigned long populated;
 331         int i;
 332         int op;
 333
 334         max_pfn = min(MAX_DOMAIN_PAGES, max_pfn);
 335         mem_end = PFN_PHYS(max_pfn);
 336
 337         memmap.nr_entries = E820MAX;
 338         set_xen_guest_handle(memmap.buffer, map);
 339
 340         op = xen_initial_domain() ?
 341                 XENMEM_machine_memory_map :
 342                 XENMEM_memory_map;
 343         rc = HYPERVISOR_memory_op(op, &memmap);
 344         if (rc == -ENOSYS) {
 345                 BUG_ON(xen_initial_domain());
 346                 memmap.nr_entries = 1;
 347                 map[0].addr = 0ULL;
 348                 map[0].size = mem_end;
 349                 /* 8MB slack (to balance backend allocations). */
 350                 map[0].size += 8ULL << 20;
 351                 map[0].type = E820_RAM;
 352                 rc = 0;
 353         }
 354         BUG_ON(rc);
 355
 356         /* Make sure the Xen-supplied memory map is well-ordered. */
 357         sanitize_e820_map(map, memmap.nr_entries, &memmap.nr_entries);
 358
 359         max_pages = xen_get_max_pages();
 360         if (max_pages > max_pfn)
 361                 extra_pages += max_pages - max_pfn;
 362
 363         /*
 364          * Set P2M for all non-RAM pages and E820 gaps to be identity
 365          * type PFNs.  Any RAM pages that would be made inaccesible by
 366          * this are first released.
 367          */
 368         xen_released_pages = xen_set_identity_and_release(
 369                 map, memmap.nr_entries, max_pfn);
 370
 371         /*
 372          * Populate back the non-RAM pages and E820 gaps that had been
 373          * released. */
 374         populated = xen_populate_chunk(map, memmap.nr_entries,
 375                         max_pfn, &last_pfn, xen_released_pages);
 376
 377         xen_released_pages -= populated;
 378         extra_pages += xen_released_pages;
 379
 380         if (last_pfn > max_pfn) {
 381                 max_pfn = min(MAX_DOMAIN_PAGES, last_pfn);
 382                 mem_end = PFN_PHYS(max_pfn);
 383         }
 384         /*
 385          * Clamp the amount of extra memory to a EXTRA_MEM_RATIO
 386          * factor the base size.  On non-highmem systems, the base
 387          * size is the full initial memory allocation; on highmem it
 388          * is limited to the max size of lowmem, so that it doesn't
 389          * get completely filled.
 390          *
 391          * In principle there could be a problem in lowmem systems if
 392          * the initial memory is also very large with respect to
 393          * lowmem, but we won't try to deal with that here.
 394          */
 395         extra_pages = min(EXTRA_MEM_RATIO * min(max_pfn, PFN_DOWN(MAXMEM)),
 396                           extra_pages);
 397         i = 0;
 398         while (i < memmap.nr_entries) {
 399                 u64 addr = map[i].addr;
 400                 u64 size = map[i].size;
 401                 u32 type = map[i].type;
 402
 403                 if (type == E820_RAM) {
 404                         if (addr < mem_end) {
 405                                 size = min(size, mem_end - addr);
 406                         } else if (extra_pages) {
 407                                 size = min(size, (u64)extra_pages * PAGE_SIZE);
 408                                 extra_pages -= size / PAGE_SIZE;
 409                                 xen_add_extra_mem(addr, size);
 410                         } else
 411                                 type = E820_UNUSABLE;
 412                 }
 413
 414                 xen_align_and_add_e820_region(addr, size, type);
 415
 416                 map[i].addr += size;
 417                 map[i].size -= size;
 418                 if (map[i].size == 0)
 419                         i++;
 420         }
 421
 422         /*
 423          * In domU, the ISA region is normal, usable memory, but we
 424          * reserve ISA memory anyway because too many things poke
 425          * about in there.
 426          */
 427         e820_add_region(ISA_START_ADDRESS, ISA_END_ADDRESS - ISA_START_ADDRESS,
 428                         E820_RESERVED);
 429
 430         /*
 431          * Reserve Xen bits:
 432          *  - mfn_list
 433          *  - xen_start_info
 434          * See comment above "struct start_info" in <xen/interface/xen.h>
 435          * We tried to make the the memblock_reserve more selective so
 436          * that it would be clear what region is reserved. Sadly we ran
 437          * in the problem wherein on a 64-bit hypervisor with a 32-bit
 438          * initial domain, the pt_base has the cr3 value which is not
 439          * neccessarily where the pagetable starts! As Jan put it: "
 440          * Actually, the adjustment turns out to be correct: The page
 441          * tables for a 32-on-64 dom0 get allocated in the order "first L1",
 442          * "first L2", "first L3", so the offset to the page table base is
 443          * indeed 2. When reading xen/include/public/xen.h's comment
 444          * very strictly, this is not a violation (since there nothing is said
 445          * that the first thing in the page table space is pointed to by
 446          * pt_base; I admit that this seems to be implied though, namely
 447          * do I think that it is implied that the page table space is the
 448          * range [pt_base, pt_base + nt_pt_frames), whereas that
 449          * range here indeed is [pt_base - 2, pt_base - 2 + nt_pt_frames),
 450          * which - without a priori knowledge - the kernel would have
 451          * difficulty to figure out)." - so lets just fall back to the
 452          * easy way and reserve the whole region.
 453          */
 454         memblock_reserve(__pa(xen_start_info->mfn_list),
 455                          xen_start_info->pt_base - xen_start_info->mfn_list);
 456
 457         sanitize_e820_map(e820.map, ARRAY_SIZE(e820.map), &e820.nr_map);
 458
 459         return "Xen";
 460 }
 461
 462 /*
 463  * Set the bit indicating "nosegneg" library variants should be used.
 464  * We only need to bother in pure 32-bit mode; compat 32-bit processes
 465  * can have un-truncated segments, so wrapping around is allowed.
 466  */
 467 static void __init fiddle_vdso(void)
 468 {
 469 #ifdef CONFIG_X86_32
 470         u32 *mask;
 471         mask = VDSO32_SYMBOL(&vdso32_int80_start, NOTE_MASK);
 472         *mask |= 1 << VDSO_NOTE_NONEGSEG_BIT;
 473         mask = VDSO32_SYMBOL(&vdso32_sysenter_start, NOTE_MASK);
 474         *mask |= 1 << VDSO_NOTE_NONEGSEG_BIT;
 475 #endif
 476 }
 477
 478 static int __cpuinit register_callback(unsigned type, const void *func)
 479 {
 480         struct callback_register callback = {
 481                 .type = type,
 482                 .address = XEN_CALLBACK(__KERNEL_CS, func),
 483                 .flags = CALLBACKF_mask_events,
 484         };
 485
 486         return HYPERVISOR_callback_op(CALLBACKOP_register, &callback);
 487 }
 488
 489 void __cpuinit xen_enable_sysenter(void)
 490 {
 491         int ret;
 492         unsigned sysenter_feature;
 493
 494 #ifdef CONFIG_X86_32
 495         sysenter_feature = X86_FEATURE_SEP;
 496 #else
 497         sysenter_feature = X86_FEATURE_SYSENTER32;
 498 #endif
 499
 500         if (!boot_cpu_has(sysenter_feature))
 501                 return;
 502
 503         ret = register_callback(CALLBACKTYPE_sysenter, xen_sysenter_target);
 504         if(ret != 0)
 505                 setup_clear_cpu_cap(sysenter_feature);
 506 }
 507
 508 void __cpuinit xen_enable_syscall(void)
 509 {
 510 #ifdef CONFIG_X86_64
 511         int ret;
 512
 513         ret = register_callback(CALLBACKTYPE_syscall, xen_syscall_target);
 514         if (ret != 0) {
 515                 printk(KERN_ERR "Failed to set syscall callback: %d\n", ret);
 516                 /* Pretty fatal; 64-bit userspace has no other
 517                    mechanism for syscalls. */
 518         }
 519
 520         if (boot_cpu_has(X86_FEATURE_SYSCALL32)) {
 521                 ret = register_callback(CALLBACKTYPE_syscall32,
 522                                         xen_syscall32_target);
 523                 if (ret != 0)
 524                         setup_clear_cpu_cap(X86_FEATURE_SYSCALL32);
 525         }
 526 #endif /* CONFIG_X86_64 */
 527 }
 528
 529 void __init xen_arch_setup(void)
 530 {
 531         xen_panic_handler_init();
 532
 533         HYPERVISOR_vm_assist(VMASST_CMD_enable, VMASST_TYPE_4gb_segments);
 534         HYPERVISOR_vm_assist(VMASST_CMD_enable, VMASST_TYPE_writable_pagetables);
 535
 536         if (!xen_feature(XENFEAT_auto_translated_physmap))
 537                 HYPERVISOR_vm_assist(VMASST_CMD_enable,
 538                                      VMASST_TYPE_pae_extended_cr3);
 539
 540         if (register_callback(CALLBACKTYPE_event, xen_hypervisor_callback) ||
 541             register_callback(CALLBACKTYPE_failsafe, xen_failsafe_callback))
 542                 BUG();
 543
 544         xen_enable_sysenter();
 545         xen_enable_syscall();
 546
 547 #ifdef CONFIG_ACPI
 548         if (!(xen_start_info->flags & SIF_INITDOMAIN)) {
 549                 printk(KERN_INFO "ACPI in unprivileged domain disabled\n");
 550                 disable_acpi();
 551         }
 552 #endif
 553
 554         memcpy(boot_command_line, xen_start_info->cmd_line,
 555                MAX_GUEST_CMDLINE > COMMAND_LINE_SIZE ?
 556                COMMAND_LINE_SIZE : MAX_GUEST_CMDLINE);
 557
 558         /* Set up idle, making sure it calls safe_halt() pvop */
 559 #ifdef CONFIG_X86_32
 560         boot_cpu_data.hlt_works_ok = 1;
 561 #endif
 562         disable_cpuidle();
 563         disable_cpufreq();
 564         WARN_ON(set_pm_idle_to_default());
 565         fiddle_vdso();
 566 #ifdef CONFIG_NUMA
 567         numa_off = 1;
 568 #endif
 569 }