arch/i386/xen/enlighten.c

   1 /*
   2  * Core of Xen paravirt_ops implementation.
   3  *
   4  * This file contains the xen_paravirt_ops structure itself, and the
   5  * implementations for:
   6  * - privileged instructions
   7  * - interrupt flags
   8  * - segment operations
   9  * - booting and setup
  10  *
  11  * Jeremy Fitzhardinge <jeremy@xensource.com>, XenSource Inc, 2007
  12  */
  13
  14 #include <linux/kernel.h>
  15 #include <linux/init.h>
  16 #include <linux/smp.h>
  17 #include <linux/preempt.h>
  18 #include <linux/hardirq.h>
  19 #include <linux/percpu.h>
  20 #include <linux/delay.h>
  21 #include <linux/start_kernel.h>
  22 #include <linux/sched.h>
  23 #include <linux/bootmem.h>
  24 #include <linux/module.h>
  25 #include <linux/mm.h>
  26 #include <linux/page-flags.h>
  27 #include <linux/highmem.h>
  28 #include <linux/smp.h>
  29
  30 #include <xen/interface/xen.h>
  31 #include <xen/interface/physdev.h>
  32 #include <xen/interface/vcpu.h>
  33 #include <xen/interface/sched.h>
  34 #include <xen/features.h>
  35 #include <xen/page.h>
  36
  37 #include <asm/paravirt.h>
  38 #include <asm/page.h>
  39 #include <asm/xen/hypercall.h>
  40 #include <asm/xen/hypervisor.h>
  41 #include <asm/fixmap.h>
  42 #include <asm/processor.h>
  43 #include <asm/setup.h>
  44 #include <asm/desc.h>
  45 #include <asm/pgtable.h>
  46 #include <asm/tlbflush.h>
  47 #include <asm/reboot.h>
  48
  49 #include "xen-ops.h"
  50 #include "mmu.h"
  51 #include "multicalls.h"
  52
  53 EXPORT_SYMBOL_GPL(hypercall_page);
  54
  55 DEFINE_PER_CPU(enum paravirt_lazy_mode, xen_lazy_mode);
  56
  57 DEFINE_PER_CPU(struct vcpu_info *, xen_vcpu);
  58 DEFINE_PER_CPU(struct vcpu_info, xen_vcpu_info);
  59 DEFINE_PER_CPU(unsigned long, xen_cr3);
  60
  61 struct start_info *xen_start_info;
  62 EXPORT_SYMBOL_GPL(xen_start_info);
  63
  64 void xen_vcpu_setup(int cpu)
  65 {
  66         per_cpu(xen_vcpu, cpu) = &HYPERVISOR_shared_info->vcpu_info[cpu];
  67 }
  68
  69 static void __init xen_banner(void)
  70 {
  71         printk(KERN_INFO "Booting paravirtualized kernel on %s\n",
  72                paravirt_ops.name);
  73         printk(KERN_INFO "Hypervisor signature: %s\n", xen_start_info->magic);
  74 }
  75
  76 static void xen_cpuid(unsigned int *eax, unsigned int *ebx,
  77                       unsigned int *ecx, unsigned int *edx)
  78 {
  79         unsigned maskedx = ~0;
  80
  81         /*
  82          * Mask out inconvenient features, to try and disable as many
  83          * unsupported kernel subsystems as possible.
  84          */
  85         if (*eax == 1)
  86                 maskedx = ~((1 << X86_FEATURE_APIC) |  /* disable APIC */
  87                             (1 << X86_FEATURE_ACPI) |  /* disable ACPI */
  88                             (1 << X86_FEATURE_ACC));   /* thermal monitoring */
  89
  90         asm(XEN_EMULATE_PREFIX "cpuid"
  91                 : "=a" (*eax),
  92                   "=b" (*ebx),
  93                   "=c" (*ecx),
  94                   "=d" (*edx)
  95                 : "0" (*eax), "2" (*ecx));
  96         *edx &= maskedx;
  97 }
  98
  99 static void xen_set_debugreg(int reg, unsigned long val)
 100 {
 101         HYPERVISOR_set_debugreg(reg, val);
 102 }
 103
 104 static unsigned long xen_get_debugreg(int reg)
 105 {
 106         return HYPERVISOR_get_debugreg(reg);
 107 }
 108
 109 static unsigned long xen_save_fl(void)
 110 {
 111         struct vcpu_info *vcpu;
 112         unsigned long flags;
 113
 114         vcpu = x86_read_percpu(xen_vcpu);
 115
 116         /* flag has opposite sense of mask */
 117         flags = !vcpu->evtchn_upcall_mask;
 118
 119         /* convert to IF type flag
 120            -0 -> 0x00000000
 121            -1 -> 0xffffffff
 122         */
 123         return (-flags) & X86_EFLAGS_IF;
 124 }
 125
 126 static void xen_restore_fl(unsigned long flags)
 127 {
 128         struct vcpu_info *vcpu;
 129
 130         /* convert from IF type flag */
 131         flags = !(flags & X86_EFLAGS_IF);
 132
 133         /* There's a one instruction preempt window here.  We need to
 134            make sure we're don't switch CPUs between getting the vcpu
 135            pointer and updating the mask. */
 136         preempt_disable();
 137         vcpu = x86_read_percpu(xen_vcpu);
 138         vcpu->evtchn_upcall_mask = flags;
 139         preempt_enable_no_resched();
 140
 141         /* Doesn't matter if we get preempted here, because any
 142            pending event will get dealt with anyway. */
 143
 144         if (flags == 0) {
 145                 preempt_check_resched();
 146                 barrier(); /* unmask then check (avoid races) */
 147                 if (unlikely(vcpu->evtchn_upcall_pending))
 148                         force_evtchn_callback();
 149         }
 150 }
 151
 152 static void xen_irq_disable(void)
 153 {
 154         /* There's a one instruction preempt window here.  We need to
 155            make sure we're don't switch CPUs between getting the vcpu
 156            pointer and updating the mask. */
 157         preempt_disable();
 158         x86_read_percpu(xen_vcpu)->evtchn_upcall_mask = 1;
 159         preempt_enable_no_resched();
 160 }
 161
 162 static void xen_irq_enable(void)
 163 {
 164         struct vcpu_info *vcpu;
 165
 166         /* There's a one instruction preempt window here.  We need to
 167            make sure we're don't switch CPUs between getting the vcpu
 168            pointer and updating the mask. */
 169         preempt_disable();
 170         vcpu = x86_read_percpu(xen_vcpu);
 171         vcpu->evtchn_upcall_mask = 0;
 172         preempt_enable_no_resched();
 173
 174         /* Doesn't matter if we get preempted here, because any
 175            pending event will get dealt with anyway. */
 176
 177         barrier(); /* unmask then check (avoid races) */
 178         if (unlikely(vcpu->evtchn_upcall_pending))
 179                 force_evtchn_callback();
 180 }
 181
 182 static void xen_safe_halt(void)
 183 {
 184         /* Blocking includes an implicit local_irq_enable(). */
 185         if (HYPERVISOR_sched_op(SCHEDOP_block, 0) != 0)
 186                 BUG();
 187 }
 188
 189 static void xen_halt(void)
 190 {
 191         if (irqs_disabled())
 192                 HYPERVISOR_vcpu_op(VCPUOP_down, smp_processor_id(), NULL);
 193         else
 194                 xen_safe_halt();
 195 }
 196
 197 static void xen_set_lazy_mode(enum paravirt_lazy_mode mode)
 198 {
 199         BUG_ON(preemptible());
 200
 201         switch (mode) {
 202         case PARAVIRT_LAZY_NONE:
 203                 BUG_ON(x86_read_percpu(xen_lazy_mode) == PARAVIRT_LAZY_NONE);
 204                 break;
 205
 206         case PARAVIRT_LAZY_MMU:
 207         case PARAVIRT_LAZY_CPU:
 208                 BUG_ON(x86_read_percpu(xen_lazy_mode) != PARAVIRT_LAZY_NONE);
 209                 break;
 210
 211         case PARAVIRT_LAZY_FLUSH:
 212                 /* flush if necessary, but don't change state */
 213                 if (x86_read_percpu(xen_lazy_mode) != PARAVIRT_LAZY_NONE)
 214                         xen_mc_flush();
 215                 return;
 216         }
 217
 218         xen_mc_flush();
 219         x86_write_percpu(xen_lazy_mode, mode);
 220 }
 221
 222 static unsigned long xen_store_tr(void)
 223 {
 224         return 0;
 225 }
 226
 227 static void xen_set_ldt(const void *addr, unsigned entries)
 228 {
 229         unsigned long linear_addr = (unsigned long)addr;
 230         struct mmuext_op *op;
 231         struct multicall_space mcs = xen_mc_entry(sizeof(*op));
 232
 233         op = mcs.args;
 234         op->cmd = MMUEXT_SET_LDT;
 235         if (linear_addr) {
 236                 /* ldt my be vmalloced, use arbitrary_virt_to_machine */
 237                 xmaddr_t maddr;
 238                 maddr = arbitrary_virt_to_machine((unsigned long)addr);
 239                 linear_addr = (unsigned long)maddr.maddr;
 240         }
 241         op->arg1.linear_addr = linear_addr;
 242         op->arg2.nr_ents = entries;
 243
 244         MULTI_mmuext_op(mcs.mc, op, 1, NULL, DOMID_SELF);
 245
 246         xen_mc_issue(PARAVIRT_LAZY_CPU);
 247 }
 248
 249 static void xen_load_gdt(const struct Xgt_desc_struct *dtr)
 250 {
 251         unsigned long *frames;
 252         unsigned long va = dtr->address;
 253         unsigned int size = dtr->size + 1;
 254         unsigned pages = (size + PAGE_SIZE - 1) / PAGE_SIZE;
 255         int f;
 256         struct multicall_space mcs;
 257
 258         /* A GDT can be up to 64k in size, which corresponds to 8192
 259            8-byte entries, or 16 4k pages.. */
 260
 261         BUG_ON(size > 65536);
 262         BUG_ON(va & ~PAGE_MASK);
 263
 264         mcs = xen_mc_entry(sizeof(*frames) * pages);
 265         frames = mcs.args;
 266
 267         for (f = 0; va < dtr->address + size; va += PAGE_SIZE, f++) {
 268                 frames[f] = virt_to_mfn(va);
 269                 make_lowmem_page_readonly((void *)va);
 270         }
 271
 272         MULTI_set_gdt(mcs.mc, frames, size / sizeof(struct desc_struct));
 273
 274         xen_mc_issue(PARAVIRT_LAZY_CPU);
 275 }
 276
 277 static void load_TLS_descriptor(struct thread_struct *t,
 278                                 unsigned int cpu, unsigned int i)
 279 {
 280         struct desc_struct *gdt = get_cpu_gdt_table(cpu);
 281         xmaddr_t maddr = virt_to_machine(&gdt[GDT_ENTRY_TLS_MIN+i]);
 282         struct multicall_space mc = __xen_mc_entry(0);
 283
 284         MULTI_update_descriptor(mc.mc, maddr.maddr, t->tls_array[i]);
 285 }
 286
 287 static void xen_load_tls(struct thread_struct *t, unsigned int cpu)
 288 {
 289         xen_mc_batch();
 290
 291         load_TLS_descriptor(t, cpu, 0);
 292         load_TLS_descriptor(t, cpu, 1);
 293         load_TLS_descriptor(t, cpu, 2);
 294
 295         xen_mc_issue(PARAVIRT_LAZY_CPU);
 296
 297         /*
 298          * XXX sleazy hack: If we're being called in a lazy-cpu zone,
 299          * it means we're in a context switch, and %gs has just been
 300          * saved.  This means we can zero it out to prevent faults on
 301          * exit from the hypervisor if the next process has no %gs.
 302          * Either way, it has been saved, and the new value will get
 303          * loaded properly.  This will go away as soon as Xen has been
 304          * modified to not save/restore %gs for normal hypercalls.
 305          */
 306         if (xen_get_lazy_mode() == PARAVIRT_LAZY_CPU)
 307                 loadsegment(gs, 0);
 308 }
 309
 310 static void xen_write_ldt_entry(struct desc_struct *dt, int entrynum,
 311                                 u32 low, u32 high)
 312 {
 313         unsigned long lp = (unsigned long)&dt[entrynum];
 314         xmaddr_t mach_lp = virt_to_machine(lp);
 315         u64 entry = (u64)high << 32 | low;
 316
 317         preempt_disable();
 318
 319         xen_mc_flush();
 320         if (HYPERVISOR_update_descriptor(mach_lp.maddr, entry))
 321                 BUG();
 322
 323         preempt_enable();
 324 }
 325
 326 static int cvt_gate_to_trap(int vector, u32 low, u32 high,
 327                             struct trap_info *info)
 328 {
 329         u8 type, dpl;
 330
 331         type = (high >> 8) & 0x1f;
 332         dpl = (high >> 13) & 3;
 333
 334         if (type != 0xf && type != 0xe)
 335                 return 0;
 336
 337         info->vector = vector;
 338         info->address = (high & 0xffff0000) | (low & 0x0000ffff);
 339         info->cs = low >> 16;
 340         info->flags = dpl;
 341         /* interrupt gates clear IF */
 342         if (type == 0xe)
 343                 info->flags |= 4;
 344
 345         return 1;
 346 }
 347
 348 /* Locations of each CPU's IDT */
 349 static DEFINE_PER_CPU(struct Xgt_desc_struct, idt_desc);
 350
 351 /* Set an IDT entry.  If the entry is part of the current IDT, then
 352    also update Xen. */
 353 static void xen_write_idt_entry(struct desc_struct *dt, int entrynum,
 354                                 u32 low, u32 high)
 355 {
 356         unsigned long p = (unsigned long)&dt[entrynum];
 357         unsigned long start, end;
 358
 359         preempt_disable();
 360
 361         start = __get_cpu_var(idt_desc).address;
 362         end = start + __get_cpu_var(idt_desc).size + 1;
 363
 364         xen_mc_flush();
 365
 366         write_dt_entry(dt, entrynum, low, high);
 367
 368         if (p >= start && (p + 8) <= end) {
 369                 struct trap_info info[2];
 370
 371                 info[1].address = 0;
 372
 373                 if (cvt_gate_to_trap(entrynum, low, high, &info[0]))
 374                         if (HYPERVISOR_set_trap_table(info))
 375                                 BUG();
 376         }
 377
 378         preempt_enable();
 379 }
 380
 381 static void xen_convert_trap_info(const struct Xgt_desc_struct *desc,
 382                                   struct trap_info *traps)
 383 {
 384         unsigned in, out, count;
 385
 386         count = (desc->size+1) / 8;
 387         BUG_ON(count > 256);
 388
 389         for (in = out = 0; in < count; in++) {
 390                 const u32 *entry = (u32 *)(desc->address + in * 8);
 391
 392                 if (cvt_gate_to_trap(in, entry[0], entry[1], &traps[out]))
 393                         out++;
 394         }
 395         traps[out].address = 0;
 396 }
 397
 398 void xen_copy_trap_info(struct trap_info *traps)
 399 {
 400         const struct Xgt_desc_struct *desc = &__get_cpu_var(idt_desc);
 401
 402         xen_convert_trap_info(desc, traps);
 403 }
 404
 405 /* Load a new IDT into Xen.  In principle this can be per-CPU, so we
 406    hold a spinlock to protect the static traps[] array (static because
 407    it avoids allocation, and saves stack space). */
 408 static void xen_load_idt(const struct Xgt_desc_struct *desc)
 409 {
 410         static DEFINE_SPINLOCK(lock);
 411         static struct trap_info traps[257];
 412
 413         spin_lock(&lock);
 414
 415         __get_cpu_var(idt_desc) = *desc;
 416
 417         xen_convert_trap_info(desc, traps);
 418
 419         xen_mc_flush();
 420         if (HYPERVISOR_set_trap_table(traps))
 421                 BUG();
 422
 423         spin_unlock(&lock);
 424 }
 425
 426 /* Write a GDT descriptor entry.  Ignore LDT descriptors, since
 427    they're handled differently. */
 428 static void xen_write_gdt_entry(struct desc_struct *dt, int entry,
 429                                 u32 low, u32 high)
 430 {
 431         preempt_disable();
 432
 433         switch ((high >> 8) & 0xff) {
 434         case DESCTYPE_LDT:
 435         case DESCTYPE_TSS:
 436                 /* ignore */
 437                 break;
 438
 439         default: {
 440                 xmaddr_t maddr = virt_to_machine(&dt[entry]);
 441                 u64 desc = (u64)high << 32 | low;
 442
 443                 xen_mc_flush();
 444                 if (HYPERVISOR_update_descriptor(maddr.maddr, desc))
 445                         BUG();
 446         }
 447
 448         }
 449
 450         preempt_enable();
 451 }
 452
 453 static void xen_load_esp0(struct tss_struct *tss,
 454                           struct thread_struct *thread)
 455 {
 456         struct multicall_space mcs = xen_mc_entry(0);
 457         MULTI_stack_switch(mcs.mc, __KERNEL_DS, thread->esp0);
 458         xen_mc_issue(PARAVIRT_LAZY_CPU);
 459 }
 460
 461 static void xen_set_iopl_mask(unsigned mask)
 462 {
 463         struct physdev_set_iopl set_iopl;
 464
 465         /* Force the change at ring 0. */
 466         set_iopl.iopl = (mask == 0) ? 1 : (mask >> 12) & 3;
 467         HYPERVISOR_physdev_op(PHYSDEVOP_set_iopl, &set_iopl);
 468 }
 469
 470 static void xen_io_delay(void)
 471 {
 472 }
 473
 474 #ifdef CONFIG_X86_LOCAL_APIC
 475 static unsigned long xen_apic_read(unsigned long reg)
 476 {
 477         return 0;
 478 }
 479
 480 static void xen_apic_write(unsigned long reg, unsigned long val)
 481 {
 482         /* Warn to see if there's any stray references */
 483         WARN_ON(1);
 484 }
 485 #endif
 486
 487 static void xen_flush_tlb(void)
 488 {
 489         struct mmuext_op *op;
 490         struct multicall_space mcs = xen_mc_entry(sizeof(*op));
 491
 492         op = mcs.args;
 493         op->cmd = MMUEXT_TLB_FLUSH_LOCAL;
 494         MULTI_mmuext_op(mcs.mc, op, 1, NULL, DOMID_SELF);
 495
 496         xen_mc_issue(PARAVIRT_LAZY_MMU);
 497 }
 498
 499 static void xen_flush_tlb_single(unsigned long addr)
 500 {
 501         struct mmuext_op *op;
 502         struct multicall_space mcs = xen_mc_entry(sizeof(*op));
 503
 504         op = mcs.args;
 505         op->cmd = MMUEXT_INVLPG_LOCAL;
 506         op->arg1.linear_addr = addr & PAGE_MASK;
 507         MULTI_mmuext_op(mcs.mc, op, 1, NULL, DOMID_SELF);
 508
 509         xen_mc_issue(PARAVIRT_LAZY_MMU);
 510 }
 511
 512 static void xen_flush_tlb_others(const cpumask_t *cpus, struct mm_struct *mm,
 513                                  unsigned long va)
 514 {
 515         struct {
 516                 struct mmuext_op op;
 517                 cpumask_t mask;
 518         } *args;
 519         cpumask_t cpumask = *cpus;
 520         struct multicall_space mcs;
 521
 522         /*
 523          * A couple of (to be removed) sanity checks:
 524          *
 525          * - current CPU must not be in mask
 526          * - mask must exist :)
 527          */
 528         BUG_ON(cpus_empty(cpumask));
 529         BUG_ON(cpu_isset(smp_processor_id(), cpumask));
 530         BUG_ON(!mm);
 531
 532         /* If a CPU which we ran on has gone down, OK. */
 533         cpus_and(cpumask, cpumask, cpu_online_map);
 534         if (cpus_empty(cpumask))
 535                 return;
 536
 537         mcs = xen_mc_entry(sizeof(*args));
 538         args = mcs.args;
 539         args->mask = cpumask;
 540         args->op.arg2.vcpumask = &args->mask;
 541
 542         if (va == TLB_FLUSH_ALL) {
 543                 args->op.cmd = MMUEXT_TLB_FLUSH_MULTI;
 544         } else {
 545                 args->op.cmd = MMUEXT_INVLPG_MULTI;
 546                 args->op.arg1.linear_addr = va;
 547         }
 548
 549         MULTI_mmuext_op(mcs.mc, &args->op, 1, NULL, DOMID_SELF);
 550
 551         xen_mc_issue(PARAVIRT_LAZY_MMU);
 552 }
 553
 554 static unsigned long xen_read_cr2(void)
 555 {
 556         return x86_read_percpu(xen_vcpu)->arch.cr2;
 557 }
 558
 559 static void xen_write_cr4(unsigned long cr4)
 560 {
 561         /* never allow TSC to be disabled */
 562         native_write_cr4(cr4 & ~X86_CR4_TSD);
 563 }
 564
 565 static unsigned long xen_read_cr3(void)
 566 {
 567         return x86_read_percpu(xen_cr3);
 568 }
 569
 570 static void xen_write_cr3(unsigned long cr3)
 571 {
 572         BUG_ON(preemptible());
 573
 574         if (cr3 == x86_read_percpu(xen_cr3)) {
 575                 /* just a simple tlb flush */
 576                 xen_flush_tlb();
 577                 return;
 578         }
 579
 580         x86_write_percpu(xen_cr3, cr3);
 581
 582
 583         {
 584                 struct mmuext_op *op;
 585                 struct multicall_space mcs = xen_mc_entry(sizeof(*op));
 586                 unsigned long mfn = pfn_to_mfn(PFN_DOWN(cr3));
 587
 588                 op = mcs.args;
 589                 op->cmd = MMUEXT_NEW_BASEPTR;
 590                 op->arg1.mfn = mfn;
 591
 592                 MULTI_mmuext_op(mcs.mc, op, 1, NULL, DOMID_SELF);
 593
 594                 xen_mc_issue(PARAVIRT_LAZY_CPU);
 595         }
 596 }
 597
 598 /* Early in boot, while setting up the initial pagetable, assume
 599    everything is pinned. */
 600 static __init void xen_alloc_pt_init(struct mm_struct *mm, u32 pfn)
 601 {
 602         BUG_ON(mem_map);        /* should only be used early */
 603         make_lowmem_page_readonly(__va(PFN_PHYS(pfn)));
 604 }
 605
 606 /* This needs to make sure the new pte page is pinned iff its being
 607    attached to a pinned pagetable. */
 608 static void xen_alloc_pt(struct mm_struct *mm, u32 pfn)
 609 {
 610         struct page *page = pfn_to_page(pfn);
 611
 612         if (PagePinned(virt_to_page(mm->pgd))) {
 613                 SetPagePinned(page);
 614
 615                 if (!PageHighMem(page))
 616                         make_lowmem_page_readonly(__va(PFN_PHYS(pfn)));
 617                 else
 618                         /* make sure there are no stray mappings of
 619                            this page */
 620                         kmap_flush_unused();
 621         }
 622 }
 623
 624 /* This should never happen until we're OK to use struct page */
 625 static void xen_release_pt(u32 pfn)
 626 {
 627         struct page *page = pfn_to_page(pfn);
 628
 629         if (PagePinned(page)) {
 630                 if (!PageHighMem(page))
 631                         make_lowmem_page_readwrite(__va(PFN_PHYS(pfn)));
 632         }
 633 }
 634
 635 #ifdef CONFIG_HIGHPTE
 636 static void *xen_kmap_atomic_pte(struct page *page, enum km_type type)
 637 {
 638         pgprot_t prot = PAGE_KERNEL;
 639
 640         if (PagePinned(page))
 641                 prot = PAGE_KERNEL_RO;
 642
 643         if (0 && PageHighMem(page))
 644                 printk("mapping highpte %lx type %d prot %s\n",
 645                        page_to_pfn(page), type,
 646                        (unsigned long)pgprot_val(prot) & _PAGE_RW ? "WRITE" : "READ");
 647
 648         return kmap_atomic_prot(page, type, prot);
 649 }
 650 #endif
 651
 652 static __init pte_t mask_rw_pte(pte_t *ptep, pte_t pte)
 653 {
 654         /* If there's an existing pte, then don't allow _PAGE_RW to be set */
 655         if (pte_val_ma(*ptep) & _PAGE_PRESENT)
 656                 pte = __pte_ma(((pte_val_ma(*ptep) & _PAGE_RW) | ~_PAGE_RW) &
 657                                pte_val_ma(pte));
 658
 659         return pte;
 660 }
 661
 662 /* Init-time set_pte while constructing initial pagetables, which
 663    doesn't allow RO pagetable pages to be remapped RW */
 664 static __init void xen_set_pte_init(pte_t *ptep, pte_t pte)
 665 {
 666         pte = mask_rw_pte(ptep, pte);
 667
 668         xen_set_pte(ptep, pte);
 669 }
 670
 671 static __init void xen_pagetable_setup_start(pgd_t *base)
 672 {
 673         pgd_t *xen_pgd = (pgd_t *)xen_start_info->pt_base;
 674
 675         /* special set_pte for pagetable initialization */
 676         paravirt_ops.set_pte = xen_set_pte_init;
 677
 678         init_mm.pgd = base;
 679         /*
 680          * copy top-level of Xen-supplied pagetable into place.  For
 681          * !PAE we can use this as-is, but for PAE it is a stand-in
 682          * while we copy the pmd pages.
 683          */
 684         memcpy(base, xen_pgd, PTRS_PER_PGD * sizeof(pgd_t));
 685
 686         if (PTRS_PER_PMD > 1) {
 687                 int i;
 688                 /*
 689                  * For PAE, need to allocate new pmds, rather than
 690                  * share Xen's, since Xen doesn't like pmd's being
 691                  * shared between address spaces.
 692                  */
 693                 for (i = 0; i < PTRS_PER_PGD; i++) {
 694                         if (pgd_val_ma(xen_pgd[i]) & _PAGE_PRESENT) {
 695                                 pmd_t *pmd = (pmd_t *)alloc_bootmem_low_pages(PAGE_SIZE);
 696
 697                                 memcpy(pmd, (void *)pgd_page_vaddr(xen_pgd[i]),
 698                                        PAGE_SIZE);
 699
 700                                 make_lowmem_page_readonly(pmd);
 701
 702                                 set_pgd(&base[i], __pgd(1 + __pa(pmd)));
 703                         } else
 704                                 pgd_clear(&base[i]);
 705                 }
 706         }
 707
 708         /* make sure zero_page is mapped RO so we can use it in pagetables */
 709         make_lowmem_page_readonly(empty_zero_page);
 710         make_lowmem_page_readonly(base);
 711         /*
 712          * Switch to new pagetable.  This is done before
 713          * pagetable_init has done anything so that the new pages
 714          * added to the table can be prepared properly for Xen.
 715          */
 716         xen_write_cr3(__pa(base));
 717 }
 718
 719 static __init void xen_pagetable_setup_done(pgd_t *base)
 720 {
 721         /* This will work as long as patching hasn't happened yet
 722            (which it hasn't) */
 723         paravirt_ops.alloc_pt = xen_alloc_pt;
 724         paravirt_ops.set_pte = xen_set_pte;
 725
 726         if (!xen_feature(XENFEAT_auto_translated_physmap)) {
 727                 /*
 728                  * Create a mapping for the shared info page.
 729                  * Should be set_fixmap(), but shared_info is a machine
 730                  * address with no corresponding pseudo-phys address.
 731                  */
 732                 set_pte_mfn(fix_to_virt(FIX_PARAVIRT_BOOTMAP),
 733                             PFN_DOWN(xen_start_info->shared_info),
 734                             PAGE_KERNEL);
 735
 736                 HYPERVISOR_shared_info =
 737                         (struct shared_info *)fix_to_virt(FIX_PARAVIRT_BOOTMAP);
 738
 739         } else
 740                 HYPERVISOR_shared_info =
 741                         (struct shared_info *)__va(xen_start_info->shared_info);
 742
 743         /* Actually pin the pagetable down, but we can't set PG_pinned
 744            yet because the page structures don't exist yet. */
 745         {
 746                 struct mmuext_op op;
 747 #ifdef CONFIG_X86_PAE
 748                 op.cmd = MMUEXT_PIN_L3_TABLE;
 749 #else
 750                 op.cmd = MMUEXT_PIN_L3_TABLE;
 751 #endif
 752                 op.arg1.mfn = pfn_to_mfn(PFN_DOWN(__pa(base)));
 753                 if (HYPERVISOR_mmuext_op(&op, 1, NULL, DOMID_SELF))
 754                         BUG();
 755         }
 756
 757         xen_vcpu_setup(smp_processor_id());
 758 }
 759
 760 static const struct paravirt_ops xen_paravirt_ops __initdata = {
 761         .paravirt_enabled = 1,
 762         .shared_kernel_pmd = 0,
 763
 764         .name = "Xen",
 765         .banner = xen_banner,
 766
 767         .patch = paravirt_patch_default,
 768
 769         .memory_setup = xen_memory_setup,
 770         .arch_setup = xen_arch_setup,
 771         .init_IRQ = xen_init_IRQ,
 772         .post_allocator_init = xen_mark_init_mm_pinned,
 773
 774         .time_init = xen_time_init,
 775         .set_wallclock = xen_set_wallclock,
 776         .get_wallclock = xen_get_wallclock,
 777         .get_cpu_khz = xen_cpu_khz,
 778         .sched_clock = xen_sched_clock,
 779
 780         .cpuid = xen_cpuid,
 781
 782         .set_debugreg = xen_set_debugreg,
 783         .get_debugreg = xen_get_debugreg,
 784
 785         .clts = native_clts,
 786
 787         .read_cr0 = native_read_cr0,
 788         .write_cr0 = native_write_cr0,
 789
 790         .read_cr2 = xen_read_cr2,
 791         .write_cr2 = native_write_cr2,
 792
 793         .read_cr3 = xen_read_cr3,
 794         .write_cr3 = xen_write_cr3,
 795
 796         .read_cr4 = native_read_cr4,
 797         .read_cr4_safe = native_read_cr4_safe,
 798         .write_cr4 = xen_write_cr4,
 799
 800         .save_fl = xen_save_fl,
 801         .restore_fl = xen_restore_fl,
 802         .irq_disable = xen_irq_disable,
 803         .irq_enable = xen_irq_enable,
 804         .safe_halt = xen_safe_halt,
 805         .halt = xen_halt,
 806         .wbinvd = native_wbinvd,
 807
 808         .read_msr = native_read_msr_safe,
 809         .write_msr = native_write_msr_safe,
 810         .read_tsc = native_read_tsc,
 811         .read_pmc = native_read_pmc,
 812
 813         .iret = (void *)&hypercall_page[__HYPERVISOR_iret],
 814         .irq_enable_sysexit = NULL,  /* never called */
 815
 816         .load_tr_desc = paravirt_nop,
 817         .set_ldt = xen_set_ldt,
 818         .load_gdt = xen_load_gdt,
 819         .load_idt = xen_load_idt,
 820         .load_tls = xen_load_tls,
 821
 822         .store_gdt = native_store_gdt,
 823         .store_idt = native_store_idt,
 824         .store_tr = xen_store_tr,
 825
 826         .write_ldt_entry = xen_write_ldt_entry,
 827         .write_gdt_entry = xen_write_gdt_entry,
 828         .write_idt_entry = xen_write_idt_entry,
 829         .load_esp0 = xen_load_esp0,
 830
 831         .set_iopl_mask = xen_set_iopl_mask,
 832         .io_delay = xen_io_delay,
 833
 834 #ifdef CONFIG_X86_LOCAL_APIC
 835         .apic_write = xen_apic_write,
 836         .apic_write_atomic = xen_apic_write,
 837         .apic_read = xen_apic_read,
 838         .setup_boot_clock = paravirt_nop,
 839         .setup_secondary_clock = paravirt_nop,
 840         .startup_ipi_hook = paravirt_nop,
 841 #endif
 842
 843         .flush_tlb_user = xen_flush_tlb,
 844         .flush_tlb_kernel = xen_flush_tlb,
 845         .flush_tlb_single = xen_flush_tlb_single,
 846         .flush_tlb_others = xen_flush_tlb_others,
 847
 848         .pte_update = paravirt_nop,
 849         .pte_update_defer = paravirt_nop,
 850
 851         .pagetable_setup_start = xen_pagetable_setup_start,
 852         .pagetable_setup_done = xen_pagetable_setup_done,
 853
 854         .alloc_pt = xen_alloc_pt_init,
 855         .release_pt = xen_release_pt,
 856         .alloc_pd = paravirt_nop,
 857         .alloc_pd_clone = paravirt_nop,
 858         .release_pd = paravirt_nop,
 859
 860 #ifdef CONFIG_HIGHPTE
 861         .kmap_atomic_pte = xen_kmap_atomic_pte,
 862 #endif
 863
 864         .set_pte = NULL,        /* see xen_pagetable_setup_* */
 865         .set_pte_at = xen_set_pte_at,
 866         .set_pmd = xen_set_pmd,
 867
 868         .pte_val = xen_pte_val,
 869         .pgd_val = xen_pgd_val,
 870
 871         .make_pte = xen_make_pte,
 872         .make_pgd = xen_make_pgd,
 873
 874 #ifdef CONFIG_X86_PAE
 875         .set_pte_atomic = xen_set_pte_atomic,
 876         .set_pte_present = xen_set_pte_at,
 877         .set_pud = xen_set_pud,
 878         .pte_clear = xen_pte_clear,
 879         .pmd_clear = xen_pmd_clear,
 880
 881         .make_pmd = xen_make_pmd,
 882         .pmd_val = xen_pmd_val,
 883 #endif  /* PAE */
 884
 885         .activate_mm = xen_activate_mm,
 886         .dup_mmap = xen_dup_mmap,
 887         .exit_mmap = xen_exit_mmap,
 888
 889         .set_lazy_mode = xen_set_lazy_mode,
 890 };
 891
 892 #ifdef CONFIG_SMP
 893 static const struct smp_ops xen_smp_ops __initdata = {
 894         .smp_prepare_boot_cpu = xen_smp_prepare_boot_cpu,
 895         .smp_prepare_cpus = xen_smp_prepare_cpus,
 896         .cpu_up = xen_cpu_up,
 897         .smp_cpus_done = xen_smp_cpus_done,
 898
 899         .smp_send_stop = xen_smp_send_stop,
 900         .smp_send_reschedule = xen_smp_send_reschedule,
 901         .smp_call_function_mask = xen_smp_call_function_mask,
 902 };
 903 #endif  /* CONFIG_SMP */
 904
 905 static void xen_reboot(int reason)
 906 {
 907 #ifdef CONFIG_SMP
 908         smp_send_stop();
 909 #endif
 910
 911         if (HYPERVISOR_sched_op(SCHEDOP_shutdown, reason))
 912                 BUG();
 913 }
 914
 915 static void xen_restart(char *msg)
 916 {
 917         xen_reboot(SHUTDOWN_reboot);
 918 }
 919
 920 static void xen_emergency_restart(void)
 921 {
 922         xen_reboot(SHUTDOWN_reboot);
 923 }
 924
 925 static void xen_machine_halt(void)
 926 {
 927         xen_reboot(SHUTDOWN_poweroff);
 928 }
 929
 930 static void xen_crash_shutdown(struct pt_regs *regs)
 931 {
 932         xen_reboot(SHUTDOWN_crash);
 933 }
 934
 935 static const struct machine_ops __initdata xen_machine_ops = {
 936         .restart = xen_restart,
 937         .halt = xen_machine_halt,
 938         .power_off = xen_machine_halt,
 939         .shutdown = xen_machine_halt,
 940         .crash_shutdown = xen_crash_shutdown,
 941         .emergency_restart = xen_emergency_restart,
 942 };
 943
 944 /* First C function to be called on Xen boot */
 945 asmlinkage void __init xen_start_kernel(void)
 946 {
 947         pgd_t *pgd;
 948
 949         if (!xen_start_info)
 950                 return;
 951
 952         BUG_ON(memcmp(xen_start_info->magic, "xen-3.0", 7) != 0);
 953
 954         /* Install Xen paravirt ops */
 955         paravirt_ops = xen_paravirt_ops;
 956         machine_ops = xen_machine_ops;
 957
 958 #ifdef CONFIG_SMP
 959         smp_ops = xen_smp_ops;
 960 #endif
 961
 962         xen_setup_features();
 963
 964         /* Get mfn list */
 965         if (!xen_feature(XENFEAT_auto_translated_physmap))
 966                 phys_to_machine_mapping = (unsigned long *)xen_start_info->mfn_list;
 967
 968         pgd = (pgd_t *)xen_start_info->pt_base;
 969
 970         init_pg_tables_end = __pa(pgd) + xen_start_info->nr_pt_frames*PAGE_SIZE;
 971
 972         init_mm.pgd = pgd; /* use the Xen pagetables to start */
 973
 974         /* keep using Xen gdt for now; no urgent need to change it */
 975
 976         x86_write_percpu(xen_cr3, __pa(pgd));
 977         xen_vcpu_setup(0);
 978
 979         paravirt_ops.kernel_rpl = 1;
 980         if (xen_feature(XENFEAT_supervisor_mode_kernel))
 981                 paravirt_ops.kernel_rpl = 0;
 982
 983         /* set the limit of our address space */
 984         reserve_top_address(-HYPERVISOR_VIRT_START + 2 * PAGE_SIZE);
 985
 986         /* set up basic CPUID stuff */
 987         cpu_detect(&new_cpu_data);
 988         new_cpu_data.hard_math = 1;
 989         new_cpu_data.x86_capability[0] = cpuid_edx(1);
 990
 991         /* Poke various useful things into boot_params */
 992         LOADER_TYPE = (9 << 4) | 0;
 993         INITRD_START = xen_start_info->mod_start ? __pa(xen_start_info->mod_start) : 0;
 994         INITRD_SIZE = xen_start_info->mod_len;
 995
 996         /* Start the world */
 997         start_kernel();
 998 }