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
  14 #include <asm/elf.h>
  15 #include <asm/vdso.h>
  16 #include <asm/e820.h>
  17 #include <asm/setup.h>
  18 #include <asm/acpi.h>
  19 #include <asm/xen/hypervisor.h>
  20 #include <asm/xen/hypercall.h>
  21
  22 #include <xen/xen.h>
  23 #include <xen/page.h>
  24 #include <xen/interface/callback.h>
  25 #include <xen/interface/memory.h>
  26 #include <xen/interface/physdev.h>
  27 #include <xen/features.h>
  28
  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
  82         for (pfn = PFN_DOWN(start); pfn <= xen_max_p2m_pfn; pfn++)
  83                 __set_phys_to_machine(pfn, INVALID_P2M_ENTRY);
  84 }
  85
  86 static unsigned long __init xen_release_chunk(unsigned long start,
  87                                               unsigned long end)
  88 {
  89         struct xen_memory_reservation reservation = {
  90                 .address_bits = 0,
  91                 .extent_order = 0,
  92                 .domid        = DOMID_SELF
  93         };
  94         unsigned long len = 0;
  95         unsigned long pfn;
  96         int ret;
  97
  98         for(pfn = start; pfn < end; pfn++) {
  99                 unsigned long mfn = pfn_to_mfn(pfn);
 100
 101                 /* Make sure pfn exists to start with */
 102                 if (mfn == INVALID_P2M_ENTRY || mfn_to_pfn(mfn) != pfn)
 103                         continue;
 104
 105                 set_xen_guest_handle(reservation.extent_start, &mfn);
 106                 reservation.nr_extents = 1;
 107
 108                 ret = HYPERVISOR_memory_op(XENMEM_decrease_reservation,
 109                                            &reservation);
 110                 WARN(ret != 1, "Failed to release pfn %lx err=%d\n", pfn, ret);
 111                 if (ret == 1) {
 112                         __set_phys_to_machine(pfn, INVALID_P2M_ENTRY);
 113                         len++;
 114                 }
 115         }
 116         printk(KERN_INFO "Freeing  %lx-%lx pfn range: %lu pages freed\n",
 117                start, end, len);
 118
 119         return len;
 120 }
 121
 122 static unsigned long __init xen_set_identity_and_release(
 123         const struct e820entry *list, size_t map_size, unsigned long nr_pages)
 124 {
 125         phys_addr_t start = 0;
 126         unsigned long released = 0;
 127         unsigned long identity = 0;
 128         const struct e820entry *entry;
 129         int i;
 130
 131         /*
 132          * Combine non-RAM regions and gaps until a RAM region (or the
 133          * end of the map) is reached, then set the 1:1 map and
 134          * release the pages (if available) in those non-RAM regions.
 135          *
 136          * The combined non-RAM regions are rounded to a whole number
 137          * of pages so any partial pages are accessible via the 1:1
 138          * mapping.  This is needed for some BIOSes that put (for
 139          * example) the DMI tables in a reserved region that begins on
 140          * a non-page boundary.
 141          */
 142         for (i = 0, entry = list; i < map_size; i++, entry++) {
 143                 phys_addr_t end = entry->addr + entry->size;
 144
 145                 if (entry->type == E820_RAM || i == map_size - 1) {
 146                         unsigned long start_pfn = PFN_DOWN(start);
 147                         unsigned long end_pfn = PFN_UP(end);
 148
 149                         if (entry->type == E820_RAM)
 150                                 end_pfn = PFN_UP(entry->addr);
 151
 152                         if (start_pfn < end_pfn) {
 153                                 if (start_pfn < nr_pages)
 154                                         released += xen_release_chunk(
 155                                                 start_pfn, min(end_pfn, nr_pages));
 156
 157                                 identity += set_phys_range_identity(
 158                                         start_pfn, end_pfn);
 159                         }
 160                         start = end;
 161                 }
 162         }
 163
 164         printk(KERN_INFO "Released %lu pages of unused memory\n", released);
 165         printk(KERN_INFO "Set %ld page(s) to 1-1 mapping\n", identity);
 166
 167         return released;
 168 }
 169
 170 static unsigned long __init xen_get_max_pages(void)
 171 {
 172         unsigned long max_pages = MAX_DOMAIN_PAGES;
 173         domid_t domid = DOMID_SELF;
 174         int ret;
 175
 176         /*
 177          * For the initial domain we use the maximum reservation as
 178          * the maximum page.
 179          *
 180          * For guest domains the current maximum reservation reflects
 181          * the current maximum rather than the static maximum. In this
 182          * case the e820 map provided to us will cover the static
 183          * maximum region.
 184          */
 185         if (xen_initial_domain()) {
 186                 ret = HYPERVISOR_memory_op(XENMEM_maximum_reservation, &domid);
 187                 if (ret > 0)
 188                         max_pages = ret;
 189         }
 190
 191         return min(max_pages, MAX_DOMAIN_PAGES);
 192 }
 193
 194 static void xen_align_and_add_e820_region(u64 start, u64 size, int type)
 195 {
 196         u64 end = start + size;
 197
 198         /* Align RAM regions to page boundaries. */
 199         if (type == E820_RAM) {
 200                 start = PAGE_ALIGN(start);
 201                 end &= ~((u64)PAGE_SIZE - 1);
 202         }
 203
 204         e820_add_region(start, end - start, type);
 205 }
 206
 207 /**
 208  * machine_specific_memory_setup - Hook for machine specific memory setup.
 209  **/
 210 char * __init xen_memory_setup(void)
 211 {
 212         static struct e820entry map[E820MAX] __initdata;
 213
 214         unsigned long max_pfn = xen_start_info->nr_pages;
 215         unsigned long long mem_end;
 216         int rc;
 217         struct xen_memory_map memmap;
 218         unsigned long max_pages;
 219         unsigned long extra_pages = 0;
 220         int i;
 221         int op;
 222
 223         max_pfn = min(MAX_DOMAIN_PAGES, max_pfn);
 224         mem_end = PFN_PHYS(max_pfn);
 225
 226         memmap.nr_entries = E820MAX;
 227         set_xen_guest_handle(memmap.buffer, map);
 228
 229         op = xen_initial_domain() ?
 230                 XENMEM_machine_memory_map :
 231                 XENMEM_memory_map;
 232         rc = HYPERVISOR_memory_op(op, &memmap);
 233         if (rc == -ENOSYS) {
 234                 BUG_ON(xen_initial_domain());
 235                 memmap.nr_entries = 1;
 236                 map[0].addr = 0ULL;
 237                 map[0].size = mem_end;
 238                 /* 8MB slack (to balance backend allocations). */
 239                 map[0].size += 8ULL << 20;
 240                 map[0].type = E820_RAM;
 241                 rc = 0;
 242         }
 243         BUG_ON(rc);
 244
 245         /* Make sure the Xen-supplied memory map is well-ordered. */
 246         sanitize_e820_map(map, memmap.nr_entries, &memmap.nr_entries);
 247
 248         max_pages = xen_get_max_pages();
 249         if (max_pages > max_pfn)
 250                 extra_pages += max_pages - max_pfn;
 251
 252         /*
 253          * Set P2M for all non-RAM pages and E820 gaps to be identity
 254          * type PFNs.  Any RAM pages that would be made inaccesible by
 255          * this are first released.
 256          */
 257         xen_released_pages = xen_set_identity_and_release(
 258                 map, memmap.nr_entries, max_pfn);
 259         extra_pages += xen_released_pages;
 260
 261         /*
 262          * Clamp the amount of extra memory to a EXTRA_MEM_RATIO
 263          * factor the base size.  On non-highmem systems, the base
 264          * size is the full initial memory allocation; on highmem it
 265          * is limited to the max size of lowmem, so that it doesn't
 266          * get completely filled.
 267          *
 268          * In principle there could be a problem in lowmem systems if
 269          * the initial memory is also very large with respect to
 270          * lowmem, but we won't try to deal with that here.
 271          */
 272         extra_pages = min(EXTRA_MEM_RATIO * min(max_pfn, PFN_DOWN(MAXMEM)),
 273                           extra_pages);
 274
 275         i = 0;
 276         while (i < memmap.nr_entries) {
 277                 u64 addr = map[i].addr;
 278                 u64 size = map[i].size;
 279                 u32 type = map[i].type;
 280
 281                 if (type == E820_RAM) {
 282                         if (addr < mem_end) {
 283                                 size = min(size, mem_end - addr);
 284                         } else if (extra_pages) {
 285                                 size = min(size, (u64)extra_pages * PAGE_SIZE);
 286                                 extra_pages -= size / PAGE_SIZE;
 287                                 xen_add_extra_mem(addr, size);
 288                         } else
 289                                 type = E820_UNUSABLE;
 290                 }
 291
 292                 xen_align_and_add_e820_region(addr, size, type);
 293
 294                 map[i].addr += size;
 295                 map[i].size -= size;
 296                 if (map[i].size == 0)
 297                         i++;
 298         }
 299
 300         /*
 301          * In domU, the ISA region is normal, usable memory, but we
 302          * reserve ISA memory anyway because too many things poke
 303          * about in there.
 304          */
 305         e820_add_region(ISA_START_ADDRESS, ISA_END_ADDRESS - ISA_START_ADDRESS,
 306                         E820_RESERVED);
 307
 308         /*
 309          * Reserve Xen bits:
 310          *  - mfn_list
 311          *  - xen_start_info
 312          * See comment above "struct start_info" in <xen/interface/xen.h>
 313          */
 314         memblock_reserve(__pa(xen_start_info->mfn_list),
 315                          xen_start_info->pt_base - xen_start_info->mfn_list);
 316
 317         sanitize_e820_map(e820.map, ARRAY_SIZE(e820.map), &e820.nr_map);
 318
 319         return "Xen";
 320 }
 321
 322 /*
 323  * Set the bit indicating "nosegneg" library variants should be used.
 324  * We only need to bother in pure 32-bit mode; compat 32-bit processes
 325  * can have un-truncated segments, so wrapping around is allowed.
 326  */
 327 static void __init fiddle_vdso(void)
 328 {
 329 #ifdef CONFIG_X86_32
 330         u32 *mask;
 331         mask = VDSO32_SYMBOL(&vdso32_int80_start, NOTE_MASK);
 332         *mask |= 1 << VDSO_NOTE_NONEGSEG_BIT;
 333         mask = VDSO32_SYMBOL(&vdso32_sysenter_start, NOTE_MASK);
 334         *mask |= 1 << VDSO_NOTE_NONEGSEG_BIT;
 335 #endif
 336 }
 337
 338 static int __cpuinit register_callback(unsigned type, const void *func)
 339 {
 340         struct callback_register callback = {
 341                 .type = type,
 342                 .address = XEN_CALLBACK(__KERNEL_CS, func),
 343                 .flags = CALLBACKF_mask_events,
 344         };
 345
 346         return HYPERVISOR_callback_op(CALLBACKOP_register, &callback);
 347 }
 348
 349 void __cpuinit xen_enable_sysenter(void)
 350 {
 351         int ret;
 352         unsigned sysenter_feature;
 353
 354 #ifdef CONFIG_X86_32
 355         sysenter_feature = X86_FEATURE_SEP;
 356 #else
 357         sysenter_feature = X86_FEATURE_SYSENTER32;
 358 #endif
 359
 360         if (!boot_cpu_has(sysenter_feature))
 361                 return;
 362
 363         ret = register_callback(CALLBACKTYPE_sysenter, xen_sysenter_target);
 364         if(ret != 0)
 365                 setup_clear_cpu_cap(sysenter_feature);
 366 }
 367
 368 void __cpuinit xen_enable_syscall(void)
 369 {
 370 #ifdef CONFIG_X86_64
 371         int ret;
 372
 373         ret = register_callback(CALLBACKTYPE_syscall, xen_syscall_target);
 374         if (ret != 0) {
 375                 printk(KERN_ERR "Failed to set syscall callback: %d\n", ret);
 376                 /* Pretty fatal; 64-bit userspace has no other
 377                    mechanism for syscalls. */
 378         }
 379
 380         if (boot_cpu_has(X86_FEATURE_SYSCALL32)) {
 381                 ret = register_callback(CALLBACKTYPE_syscall32,
 382                                         xen_syscall32_target);
 383                 if (ret != 0)
 384                         setup_clear_cpu_cap(X86_FEATURE_SYSCALL32);
 385         }
 386 #endif /* CONFIG_X86_64 */
 387 }
 388
 389 void __init xen_arch_setup(void)
 390 {
 391         xen_panic_handler_init();
 392
 393         HYPERVISOR_vm_assist(VMASST_CMD_enable, VMASST_TYPE_4gb_segments);
 394         HYPERVISOR_vm_assist(VMASST_CMD_enable, VMASST_TYPE_writable_pagetables);
 395
 396         if (!xen_feature(XENFEAT_auto_translated_physmap))
 397                 HYPERVISOR_vm_assist(VMASST_CMD_enable,
 398                                      VMASST_TYPE_pae_extended_cr3);
 399
 400         if (register_callback(CALLBACKTYPE_event, xen_hypervisor_callback) ||
 401             register_callback(CALLBACKTYPE_failsafe, xen_failsafe_callback))
 402                 BUG();
 403
 404         xen_enable_sysenter();
 405         xen_enable_syscall();
 406
 407 #ifdef CONFIG_ACPI
 408         if (!(xen_start_info->flags & SIF_INITDOMAIN)) {
 409                 printk(KERN_INFO "ACPI in unprivileged domain disabled\n");
 410                 disable_acpi();
 411         }
 412 #endif
 413
 414         memcpy(boot_command_line, xen_start_info->cmd_line,
 415                MAX_GUEST_CMDLINE > COMMAND_LINE_SIZE ?
 416                COMMAND_LINE_SIZE : MAX_GUEST_CMDLINE);
 417
 418         /* Set up idle, making sure it calls safe_halt() pvop */
 419 #ifdef CONFIG_X86_32
 420         boot_cpu_data.hlt_works_ok = 1;
 421 #endif
 422         disable_cpuidle();
 423         boot_option_idle_override = IDLE_HALT;
 424         WARN_ON(set_pm_idle_to_default());
 425         fiddle_vdso();
 426 }