arch/x86/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/kprobes.h>
  24 #include <linux/bootmem.h>
  25 #include <linux/module.h>
  26 #include <linux/mm.h>
  27 #include <linux/page-flags.h>
  28 #include <linux/highmem.h>
  29 #include <linux/console.h>
  30
  31 #include <xen/interface/xen.h>
  32 #include <xen/interface/version.h>
  33 #include <xen/interface/physdev.h>
  34 #include <xen/interface/vcpu.h>
  35 #include <xen/features.h>
  36 #include <xen/page.h>
  37 #include <xen/hvc-console.h>
  38
  39 #include <asm/paravirt.h>
  40 #include <asm/apic.h>
  41 #include <asm/page.h>
  42 #include <asm/xen/hypercall.h>
  43 #include <asm/xen/hypervisor.h>
  44 #include <asm/fixmap.h>
  45 #include <asm/processor.h>
  46 #include <asm/proto.h>
  47 #include <asm/msr-index.h>
  48 #include <asm/traps.h>
  49 #include <asm/setup.h>
  50 #include <asm/desc.h>
  51 #include <asm/pgtable.h>
  52 #include <asm/tlbflush.h>
  53 #include <asm/reboot.h>
  54
  55 #include "xen-ops.h"
  56 #include "mmu.h"
  57 #include "multicalls.h"
  58
  59 EXPORT_SYMBOL_GPL(hypercall_page);
  60
  61 DEFINE_PER_CPU(struct vcpu_info *, xen_vcpu);
  62 DEFINE_PER_CPU(struct vcpu_info, xen_vcpu_info);
  63
  64 enum xen_domain_type xen_domain_type = XEN_NATIVE;
  65 EXPORT_SYMBOL_GPL(xen_domain_type);
  66
  67 struct start_info *xen_start_info;
  68 EXPORT_SYMBOL_GPL(xen_start_info);
  69
  70 struct shared_info xen_dummy_shared_info;
  71
  72 void *xen_initial_gdt;
  73
  74 /*
  75  * Point at some empty memory to start with. We map the real shared_info
  76  * page as soon as fixmap is up and running.
  77  */
  78 struct shared_info *HYPERVISOR_shared_info = (void *)&xen_dummy_shared_info;
  79
  80 /*
  81  * Flag to determine whether vcpu info placement is available on all
  82  * VCPUs.  We assume it is to start with, and then set it to zero on
  83  * the first failure.  This is because it can succeed on some VCPUs
  84  * and not others, since it can involve hypervisor memory allocation,
  85  * or because the guest failed to guarantee all the appropriate
  86  * constraints on all VCPUs (ie buffer can't cross a page boundary).
  87  *
  88  * Note that any particular CPU may be using a placed vcpu structure,
  89  * but we can only optimise if the all are.
  90  *
  91  * 0: not available, 1: available
  92  */
  93 static int have_vcpu_info_placement = 1;
  94
  95 static void xen_vcpu_setup(int cpu)
  96 {
  97         struct vcpu_register_vcpu_info info;
  98         int err;
  99         struct vcpu_info *vcpup;
 100
 101         BUG_ON(HYPERVISOR_shared_info == &xen_dummy_shared_info);
 102         per_cpu(xen_vcpu, cpu) = &HYPERVISOR_shared_info->vcpu_info[cpu];
 103
 104         if (!have_vcpu_info_placement)
 105                 return;         /* already tested, not available */
 106
 107         vcpup = &per_cpu(xen_vcpu_info, cpu);
 108
 109         info.mfn = arbitrary_virt_to_mfn(vcpup);
 110         info.offset = offset_in_page(vcpup);
 111
 112         printk(KERN_DEBUG "trying to map vcpu_info %d at %p, mfn %llx, offset %d\n",
 113                cpu, vcpup, info.mfn, info.offset);
 114
 115         /* Check to see if the hypervisor will put the vcpu_info
 116            structure where we want it, which allows direct access via
 117            a percpu-variable. */
 118         err = HYPERVISOR_vcpu_op(VCPUOP_register_vcpu_info, cpu, &info);
 119
 120         if (err) {
 121                 printk(KERN_DEBUG "register_vcpu_info failed: err=%d\n", err);
 122                 have_vcpu_info_placement = 0;
 123         } else {
 124                 /* This cpu is using the registered vcpu info, even if
 125                    later ones fail to. */
 126                 per_cpu(xen_vcpu, cpu) = vcpup;
 127
 128                 printk(KERN_DEBUG "cpu %d using vcpu_info at %p\n",
 129                        cpu, vcpup);
 130         }
 131 }
 132
 133 /*
 134  * On restore, set the vcpu placement up again.
 135  * If it fails, then we're in a bad state, since
 136  * we can't back out from using it...
 137  */
 138 void xen_vcpu_restore(void)
 139 {
 140         if (have_vcpu_info_placement) {
 141                 int cpu;
 142
 143                 for_each_online_cpu(cpu) {
 144                         bool other_cpu = (cpu != smp_processor_id());
 145
 146                         if (other_cpu &&
 147                             HYPERVISOR_vcpu_op(VCPUOP_down, cpu, NULL))
 148                                 BUG();
 149
 150                         xen_vcpu_setup(cpu);
 151
 152                         if (other_cpu &&
 153                             HYPERVISOR_vcpu_op(VCPUOP_up, cpu, NULL))
 154                                 BUG();
 155                 }
 156
 157                 BUG_ON(!have_vcpu_info_placement);
 158         }
 159 }
 160
 161 static void __init xen_banner(void)
 162 {
 163         unsigned version = HYPERVISOR_xen_version(XENVER_version, NULL);
 164         struct xen_extraversion extra;
 165         HYPERVISOR_xen_version(XENVER_extraversion, &extra);
 166
 167         printk(KERN_INFO "Booting paravirtualized kernel on %s\n",
 168                pv_info.name);
 169         printk(KERN_INFO "Xen version: %d.%d%s%s\n",
 170                version >> 16, version & 0xffff, extra.extraversion,
 171                xen_feature(XENFEAT_mmu_pt_update_preserve_ad) ? " (preserve-AD)" : "");
 172 }
 173
 174 static __read_mostly unsigned int cpuid_leaf1_edx_mask = ~0;
 175 static __read_mostly unsigned int cpuid_leaf1_ecx_mask = ~0;
 176
 177 static void xen_cpuid(unsigned int *ax, unsigned int *bx,
 178                       unsigned int *cx, unsigned int *dx)
 179 {
 180         unsigned maskecx = ~0;
 181         unsigned maskedx = ~0;
 182
 183         /*
 184          * Mask out inconvenient features, to try and disable as many
 185          * unsupported kernel subsystems as possible.
 186          */
 187         if (*ax == 1) {
 188                 maskecx = cpuid_leaf1_ecx_mask;
 189                 maskedx = cpuid_leaf1_edx_mask;
 190         }
 191
 192         asm(XEN_EMULATE_PREFIX "cpuid"
 193                 : "=a" (*ax),
 194                   "=b" (*bx),
 195                   "=c" (*cx),
 196                   "=d" (*dx)
 197                 : "0" (*ax), "2" (*cx));
 198
 199         *cx &= maskecx;
 200         *dx &= maskedx;
 201 }
 202
 203 static __init void xen_init_cpuid_mask(void)
 204 {
 205         unsigned int ax, bx, cx, dx;
 206
 207         cpuid_leaf1_edx_mask =
 208                 ~((1 << X86_FEATURE_MCE)  |  /* disable MCE */
 209                   (1 << X86_FEATURE_MCA)  |  /* disable MCA */
 210                   (1 << X86_FEATURE_ACC));   /* thermal monitoring */
 211
 212         if (!xen_initial_domain())
 213                 cpuid_leaf1_edx_mask &=
 214                         ~((1 << X86_FEATURE_APIC) |  /* disable local APIC */
 215                           (1 << X86_FEATURE_ACPI));  /* disable ACPI */
 216
 217         ax = 1;
 218         xen_cpuid(&ax, &bx, &cx, &dx);
 219
 220         /* cpuid claims we support xsave; try enabling it to see what happens */
 221         if (cx & (1 << (X86_FEATURE_XSAVE % 32))) {
 222                 unsigned long cr4;
 223
 224                 set_in_cr4(X86_CR4_OSXSAVE);
 225
 226                 cr4 = read_cr4();
 227
 228                 if ((cr4 & X86_CR4_OSXSAVE) == 0)
 229                         cpuid_leaf1_ecx_mask &= ~(1 << (X86_FEATURE_XSAVE % 32));
 230
 231                 clear_in_cr4(X86_CR4_OSXSAVE);
 232         }
 233 }
 234
 235 static void xen_set_debugreg(int reg, unsigned long val)
 236 {
 237         HYPERVISOR_set_debugreg(reg, val);
 238 }
 239
 240 static unsigned long xen_get_debugreg(int reg)
 241 {
 242         return HYPERVISOR_get_debugreg(reg);
 243 }
 244
 245 static void xen_end_context_switch(struct task_struct *next)
 246 {
 247         xen_mc_flush();
 248         paravirt_end_context_switch(next);
 249 }
 250
 251 static unsigned long xen_store_tr(void)
 252 {
 253         return 0;
 254 }
 255
 256 /*
 257  * Set the page permissions for a particular virtual address.  If the
 258  * address is a vmalloc mapping (or other non-linear mapping), then
 259  * find the linear mapping of the page and also set its protections to
 260  * match.
 261  */
 262 static void set_aliased_prot(void *v, pgprot_t prot)
 263 {
 264         int level;
 265         pte_t *ptep;
 266         pte_t pte;
 267         unsigned long pfn;
 268         struct page *page;
 269
 270         ptep = lookup_address((unsigned long)v, &level);
 271         BUG_ON(ptep == NULL);
 272
 273         pfn = pte_pfn(*ptep);
 274         page = pfn_to_page(pfn);
 275
 276         pte = pfn_pte(pfn, prot);
 277
 278         if (HYPERVISOR_update_va_mapping((unsigned long)v, pte, 0))
 279                 BUG();
 280
 281         if (!PageHighMem(page)) {
 282                 void *av = __va(PFN_PHYS(pfn));
 283
 284                 if (av != v)
 285                         if (HYPERVISOR_update_va_mapping((unsigned long)av, pte, 0))
 286                                 BUG();
 287         } else
 288                 kmap_flush_unused();
 289 }
 290
 291 static void xen_alloc_ldt(struct desc_struct *ldt, unsigned entries)
 292 {
 293         const unsigned entries_per_page = PAGE_SIZE / LDT_ENTRY_SIZE;
 294         int i;
 295
 296         for(i = 0; i < entries; i += entries_per_page)
 297                 set_aliased_prot(ldt + i, PAGE_KERNEL_RO);
 298 }
 299
 300 static void xen_free_ldt(struct desc_struct *ldt, unsigned entries)
 301 {
 302         const unsigned entries_per_page = PAGE_SIZE / LDT_ENTRY_SIZE;
 303         int i;
 304
 305         for(i = 0; i < entries; i += entries_per_page)
 306                 set_aliased_prot(ldt + i, PAGE_KERNEL);
 307 }
 308
 309 static void xen_set_ldt(const void *addr, unsigned entries)
 310 {
 311         struct mmuext_op *op;
 312         struct multicall_space mcs = xen_mc_entry(sizeof(*op));
 313
 314         op = mcs.args;
 315         op->cmd = MMUEXT_SET_LDT;
 316         op->arg1.linear_addr = (unsigned long)addr;
 317         op->arg2.nr_ents = entries;
 318
 319         MULTI_mmuext_op(mcs.mc, op, 1, NULL, DOMID_SELF);
 320
 321         xen_mc_issue(PARAVIRT_LAZY_CPU);
 322 }
 323
 324 static void xen_load_gdt(const struct desc_ptr *dtr)
 325 {
 326         unsigned long va = dtr->address;
 327         unsigned int size = dtr->size + 1;
 328         unsigned pages = (size + PAGE_SIZE - 1) / PAGE_SIZE;
 329         unsigned long frames[pages];
 330         int f;
 331
 332         /* A GDT can be up to 64k in size, which corresponds to 8192
 333            8-byte entries, or 16 4k pages.. */
 334
 335         BUG_ON(size > 65536);
 336         BUG_ON(va & ~PAGE_MASK);
 337
 338         for (f = 0; va < dtr->address + size; va += PAGE_SIZE, f++) {
 339                 int level;
 340                 pte_t *ptep = lookup_address(va, &level);
 341                 unsigned long pfn, mfn;
 342                 void *virt;
 343
 344                 BUG_ON(ptep == NULL);
 345
 346                 pfn = pte_pfn(*ptep);
 347                 mfn = pfn_to_mfn(pfn);
 348                 virt = __va(PFN_PHYS(pfn));
 349
 350                 frames[f] = mfn;
 351
 352                 make_lowmem_page_readonly((void *)va);
 353                 make_lowmem_page_readonly(virt);
 354         }
 355
 356         if (HYPERVISOR_set_gdt(frames, size / sizeof(struct desc_struct)))
 357                 BUG();
 358 }
 359
 360 static void load_TLS_descriptor(struct thread_struct *t,
 361                                 unsigned int cpu, unsigned int i)
 362 {
 363         struct desc_struct *gdt = get_cpu_gdt_table(cpu);
 364         xmaddr_t maddr = arbitrary_virt_to_machine(&gdt[GDT_ENTRY_TLS_MIN+i]);
 365         struct multicall_space mc = __xen_mc_entry(0);
 366
 367         MULTI_update_descriptor(mc.mc, maddr.maddr, t->tls_array[i]);
 368 }
 369
 370 static void xen_load_tls(struct thread_struct *t, unsigned int cpu)
 371 {
 372         /*
 373          * XXX sleazy hack: If we're being called in a lazy-cpu zone
 374          * and lazy gs handling is enabled, it means we're in a
 375          * context switch, and %gs has just been saved.  This means we
 376          * can zero it out to prevent faults on exit from the
 377          * hypervisor if the next process has no %gs.  Either way, it
 378          * has been saved, and the new value will get loaded properly.
 379          * This will go away as soon as Xen has been modified to not
 380          * save/restore %gs for normal hypercalls.
 381          *
 382          * On x86_64, this hack is not used for %gs, because gs points
 383          * to KERNEL_GS_BASE (and uses it for PDA references), so we
 384          * must not zero %gs on x86_64
 385          *
 386          * For x86_64, we need to zero %fs, otherwise we may get an
 387          * exception between the new %fs descriptor being loaded and
 388          * %fs being effectively cleared at __switch_to().
 389          */
 390         if (paravirt_get_lazy_mode() == PARAVIRT_LAZY_CPU) {
 391 #ifdef CONFIG_X86_32
 392                 lazy_load_gs(0);
 393 #else
 394                 loadsegment(fs, 0);
 395 #endif
 396         }
 397
 398         xen_mc_batch();
 399
 400         load_TLS_descriptor(t, cpu, 0);
 401         load_TLS_descriptor(t, cpu, 1);
 402         load_TLS_descriptor(t, cpu, 2);
 403
 404         xen_mc_issue(PARAVIRT_LAZY_CPU);
 405 }
 406
 407 #ifdef CONFIG_X86_64
 408 static void xen_load_gs_index(unsigned int idx)
 409 {
 410         if (HYPERVISOR_set_segment_base(SEGBASE_GS_USER_SEL, idx))
 411                 BUG();
 412 }
 413 #endif
 414
 415 static void xen_write_ldt_entry(struct desc_struct *dt, int entrynum,
 416                                 const void *ptr)
 417 {
 418         xmaddr_t mach_lp = arbitrary_virt_to_machine(&dt[entrynum]);
 419         u64 entry = *(u64 *)ptr;
 420
 421         preempt_disable();
 422
 423         xen_mc_flush();
 424         if (HYPERVISOR_update_descriptor(mach_lp.maddr, entry))
 425                 BUG();
 426
 427         preempt_enable();
 428 }
 429
 430 static int cvt_gate_to_trap(int vector, const gate_desc *val,
 431                             struct trap_info *info)
 432 {
 433         unsigned long addr;
 434
 435         if (val->type != GATE_TRAP && val->type != GATE_INTERRUPT)
 436                 return 0;
 437
 438         info->vector = vector;
 439
 440         addr = gate_offset(*val);
 441 #ifdef CONFIG_X86_64
 442         /*
 443          * Look for known traps using IST, and substitute them
 444          * appropriately.  The debugger ones are the only ones we care
 445          * about.  Xen will handle faults like double_fault and
 446          * machine_check, so we should never see them.  Warn if
 447          * there's an unexpected IST-using fault handler.
 448          */
 449         if (addr == (unsigned long)debug)
 450                 addr = (unsigned long)xen_debug;
 451         else if (addr == (unsigned long)int3)
 452                 addr = (unsigned long)xen_int3;
 453         else if (addr == (unsigned long)stack_segment)
 454                 addr = (unsigned long)xen_stack_segment;
 455         else if (addr == (unsigned long)double_fault ||
 456                  addr == (unsigned long)nmi) {
 457                 /* Don't need to handle these */
 458                 return 0;
 459 #ifdef CONFIG_X86_MCE
 460         } else if (addr == (unsigned long)machine_check) {
 461                 return 0;
 462 #endif
 463         } else {
 464                 /* Some other trap using IST? */
 465                 if (WARN_ON(val->ist != 0))
 466                         return 0;
 467         }
 468 #endif  /* CONFIG_X86_64 */
 469         info->address = addr;
 470
 471         info->cs = gate_segment(*val);
 472         info->flags = val->dpl;
 473         /* interrupt gates clear IF */
 474         if (val->type == GATE_INTERRUPT)
 475                 info->flags |= 1 << 2;
 476
 477         return 1;
 478 }
 479
 480 /* Locations of each CPU's IDT */
 481 static DEFINE_PER_CPU(struct desc_ptr, idt_desc);
 482
 483 /* Set an IDT entry.  If the entry is part of the current IDT, then
 484    also update Xen. */
 485 static void xen_write_idt_entry(gate_desc *dt, int entrynum, const gate_desc *g)
 486 {
 487         unsigned long p = (unsigned long)&dt[entrynum];
 488         unsigned long start, end;
 489
 490         preempt_disable();
 491
 492         start = __get_cpu_var(idt_desc).address;
 493         end = start + __get_cpu_var(idt_desc).size + 1;
 494
 495         xen_mc_flush();
 496
 497         native_write_idt_entry(dt, entrynum, g);
 498
 499         if (p >= start && (p + 8) <= end) {
 500                 struct trap_info info[2];
 501
 502                 info[1].address = 0;
 503
 504                 if (cvt_gate_to_trap(entrynum, g, &info[0]))
 505                         if (HYPERVISOR_set_trap_table(info))
 506                                 BUG();
 507         }
 508
 509         preempt_enable();
 510 }
 511
 512 static void xen_convert_trap_info(const struct desc_ptr *desc,
 513                                   struct trap_info *traps)
 514 {
 515         unsigned in, out, count;
 516
 517         count = (desc->size+1) / sizeof(gate_desc);
 518         BUG_ON(count > 256);
 519
 520         for (in = out = 0; in < count; in++) {
 521                 gate_desc *entry = (gate_desc*)(desc->address) + in;
 522
 523                 if (cvt_gate_to_trap(in, entry, &traps[out]))
 524                         out++;
 525         }
 526         traps[out].address = 0;
 527 }
 528
 529 void xen_copy_trap_info(struct trap_info *traps)
 530 {
 531         const struct desc_ptr *desc = &__get_cpu_var(idt_desc);
 532
 533         xen_convert_trap_info(desc, traps);
 534 }
 535
 536 /* Load a new IDT into Xen.  In principle this can be per-CPU, so we
 537    hold a spinlock to protect the static traps[] array (static because
 538    it avoids allocation, and saves stack space). */
 539 static void xen_load_idt(const struct desc_ptr *desc)
 540 {
 541         static DEFINE_SPINLOCK(lock);
 542         static struct trap_info traps[257];
 543
 544         spin_lock(&lock);
 545
 546         __get_cpu_var(idt_desc) = *desc;
 547
 548         xen_convert_trap_info(desc, traps);
 549
 550         xen_mc_flush();
 551         if (HYPERVISOR_set_trap_table(traps))
 552                 BUG();
 553
 554         spin_unlock(&lock);
 555 }
 556
 557 /* Write a GDT descriptor entry.  Ignore LDT descriptors, since
 558    they're handled differently. */
 559 static void xen_write_gdt_entry(struct desc_struct *dt, int entry,
 560                                 const void *desc, int type)
 561 {
 562         preempt_disable();
 563
 564         switch (type) {
 565         case DESC_LDT:
 566         case DESC_TSS:
 567                 /* ignore */
 568                 break;
 569
 570         default: {
 571                 xmaddr_t maddr = arbitrary_virt_to_machine(&dt[entry]);
 572
 573                 xen_mc_flush();
 574                 if (HYPERVISOR_update_descriptor(maddr.maddr, *(u64 *)desc))
 575                         BUG();
 576         }
 577
 578         }
 579
 580         preempt_enable();
 581 }
 582
 583 static void xen_load_sp0(struct tss_struct *tss,
 584                          struct thread_struct *thread)
 585 {
 586         struct multicall_space mcs = xen_mc_entry(0);
 587         MULTI_stack_switch(mcs.mc, __KERNEL_DS, thread->sp0);
 588         xen_mc_issue(PARAVIRT_LAZY_CPU);
 589 }
 590
 591 static void xen_set_iopl_mask(unsigned mask)
 592 {
 593         struct physdev_set_iopl set_iopl;
 594
 595         /* Force the change at ring 0. */
 596         set_iopl.iopl = (mask == 0) ? 1 : (mask >> 12) & 3;
 597         HYPERVISOR_physdev_op(PHYSDEVOP_set_iopl, &set_iopl);
 598 }
 599
 600 static void xen_io_delay(void)
 601 {
 602 }
 603
 604 #ifdef CONFIG_X86_LOCAL_APIC
 605 static u32 xen_apic_read(u32 reg)
 606 {
 607         return 0;
 608 }
 609
 610 static void xen_apic_write(u32 reg, u32 val)
 611 {
 612         /* Warn to see if there's any stray references */
 613         WARN_ON(1);
 614 }
 615
 616 static u64 xen_apic_icr_read(void)
 617 {
 618         return 0;
 619 }
 620
 621 static void xen_apic_icr_write(u32 low, u32 id)
 622 {
 623         /* Warn to see if there's any stray references */
 624         WARN_ON(1);
 625 }
 626
 627 static void xen_apic_wait_icr_idle(void)
 628 {
 629         return;
 630 }
 631
 632 static u32 xen_safe_apic_wait_icr_idle(void)
 633 {
 634         return 0;
 635 }
 636
 637 static void set_xen_basic_apic_ops(void)
 638 {
 639         apic->read = xen_apic_read;
 640         apic->write = xen_apic_write;
 641         apic->icr_read = xen_apic_icr_read;
 642         apic->icr_write = xen_apic_icr_write;
 643         apic->wait_icr_idle = xen_apic_wait_icr_idle;
 644         apic->safe_wait_icr_idle = xen_safe_apic_wait_icr_idle;
 645 }
 646
 647 #endif
 648
 649
 650 static void xen_clts(void)
 651 {
 652         struct multicall_space mcs;
 653
 654         mcs = xen_mc_entry(0);
 655
 656         MULTI_fpu_taskswitch(mcs.mc, 0);
 657
 658         xen_mc_issue(PARAVIRT_LAZY_CPU);
 659 }
 660
 661 static DEFINE_PER_CPU(unsigned long, xen_cr0_value);
 662
 663 static unsigned long xen_read_cr0(void)
 664 {
 665         unsigned long cr0 = percpu_read(xen_cr0_value);
 666
 667         if (unlikely(cr0 == 0)) {
 668                 cr0 = native_read_cr0();
 669                 percpu_write(xen_cr0_value, cr0);
 670         }
 671
 672         return cr0;
 673 }
 674
 675 static void xen_write_cr0(unsigned long cr0)
 676 {
 677         struct multicall_space mcs;
 678
 679         percpu_write(xen_cr0_value, cr0);
 680
 681         /* Only pay attention to cr0.TS; everything else is
 682            ignored. */
 683         mcs = xen_mc_entry(0);
 684
 685         MULTI_fpu_taskswitch(mcs.mc, (cr0 & X86_CR0_TS) != 0);
 686
 687         xen_mc_issue(PARAVIRT_LAZY_CPU);
 688 }
 689
 690 static void xen_write_cr4(unsigned long cr4)
 691 {
 692         cr4 &= ~X86_CR4_PGE;
 693         cr4 &= ~X86_CR4_PSE;
 694
 695         native_write_cr4(cr4);
 696 }
 697
 698 static int xen_write_msr_safe(unsigned int msr, unsigned low, unsigned high)
 699 {
 700         int ret;
 701
 702         ret = 0;
 703
 704         switch (msr) {
 705 #ifdef CONFIG_X86_64
 706                 unsigned which;
 707                 u64 base;
 708
 709         case MSR_FS_BASE:               which = SEGBASE_FS; goto set;
 710         case MSR_KERNEL_GS_BASE:        which = SEGBASE_GS_USER; goto set;
 711         case MSR_GS_BASE:               which = SEGBASE_GS_KERNEL; goto set;
 712
 713         set:
 714                 base = ((u64)high << 32) | low;
 715                 if (HYPERVISOR_set_segment_base(which, base) != 0)
 716                         ret = -EFAULT;
 717                 break;
 718 #endif
 719
 720         case MSR_STAR:
 721         case MSR_CSTAR:
 722         case MSR_LSTAR:
 723         case MSR_SYSCALL_MASK:
 724         case MSR_IA32_SYSENTER_CS:
 725         case MSR_IA32_SYSENTER_ESP:
 726         case MSR_IA32_SYSENTER_EIP:
 727                 /* Fast syscall setup is all done in hypercalls, so
 728                    these are all ignored.  Stub them out here to stop
 729                    Xen console noise. */
 730                 break;
 731
 732         default:
 733                 ret = native_write_msr_safe(msr, low, high);
 734         }
 735
 736         return ret;
 737 }
 738
 739 void xen_setup_shared_info(void)
 740 {
 741         if (!xen_feature(XENFEAT_auto_translated_physmap)) {
 742                 set_fixmap(FIX_PARAVIRT_BOOTMAP,
 743                            xen_start_info->shared_info);
 744
 745                 HYPERVISOR_shared_info =
 746                         (struct shared_info *)fix_to_virt(FIX_PARAVIRT_BOOTMAP);
 747         } else
 748                 HYPERVISOR_shared_info =
 749                         (struct shared_info *)__va(xen_start_info->shared_info);
 750
 751 #ifndef CONFIG_SMP
 752         /* In UP this is as good a place as any to set up shared info */
 753         xen_setup_vcpu_info_placement();
 754 #endif
 755
 756         xen_setup_mfn_list_list();
 757 }
 758
 759 /* This is called once we have the cpu_possible_map */
 760 void xen_setup_vcpu_info_placement(void)
 761 {
 762         int cpu;
 763
 764         for_each_possible_cpu(cpu)
 765                 xen_vcpu_setup(cpu);
 766
 767         /* xen_vcpu_setup managed to place the vcpu_info within the
 768            percpu area for all cpus, so make use of it */
 769         if (have_vcpu_info_placement) {
 770                 printk(KERN_INFO "Xen: using vcpu_info placement\n");
 771
 772                 pv_irq_ops.save_fl = __PV_IS_CALLEE_SAVE(xen_save_fl_direct);
 773                 pv_irq_ops.restore_fl = __PV_IS_CALLEE_SAVE(xen_restore_fl_direct);
 774                 pv_irq_ops.irq_disable = __PV_IS_CALLEE_SAVE(xen_irq_disable_direct);
 775                 pv_irq_ops.irq_enable = __PV_IS_CALLEE_SAVE(xen_irq_enable_direct);
 776                 pv_mmu_ops.read_cr2 = xen_read_cr2_direct;
 777         }
 778 }
 779
 780 static unsigned xen_patch(u8 type, u16 clobbers, void *insnbuf,
 781                           unsigned long addr, unsigned len)
 782 {
 783         char *start, *end, *reloc;
 784         unsigned ret;
 785
 786         start = end = reloc = NULL;
 787
 788 #define SITE(op, x)                                                     \
 789         case PARAVIRT_PATCH(op.x):                                      \
 790         if (have_vcpu_info_placement) {                                 \
 791                 start = (char *)xen_##x##_direct;                       \
 792                 end = xen_##x##_direct_end;                             \
 793                 reloc = xen_##x##_direct_reloc;                         \
 794         }                                                               \
 795         goto patch_site
 796
 797         switch (type) {
 798                 SITE(pv_irq_ops, irq_enable);
 799                 SITE(pv_irq_ops, irq_disable);
 800                 SITE(pv_irq_ops, save_fl);
 801                 SITE(pv_irq_ops, restore_fl);
 802 #undef SITE
 803
 804         patch_site:
 805                 if (start == NULL || (end-start) > len)
 806                         goto default_patch;
 807
 808                 ret = paravirt_patch_insns(insnbuf, len, start, end);
 809
 810                 /* Note: because reloc is assigned from something that
 811                    appears to be an array, gcc assumes it's non-null,
 812                    but doesn't know its relationship with start and
 813                    end. */
 814                 if (reloc > start && reloc < end) {
 815                         int reloc_off = reloc - start;
 816                         long *relocp = (long *)(insnbuf + reloc_off);
 817                         long delta = start - (char *)addr;
 818
 819                         *relocp += delta;
 820                 }
 821                 break;
 822
 823         default_patch:
 824         default:
 825                 ret = paravirt_patch_default(type, clobbers, insnbuf,
 826                                              addr, len);
 827                 break;
 828         }
 829
 830         return ret;
 831 }
 832
 833 static const struct pv_info xen_info __initdata = {
 834         .paravirt_enabled = 1,
 835         .shared_kernel_pmd = 0,
 836
 837         .name = "Xen",
 838 };
 839
 840 static const struct pv_init_ops xen_init_ops __initdata = {
 841         .patch = xen_patch,
 842
 843         .banner = xen_banner,
 844         .memory_setup = xen_memory_setup,
 845         .arch_setup = xen_arch_setup,
 846         .post_allocator_init = xen_post_allocator_init,
 847 };
 848
 849 static const struct pv_time_ops xen_time_ops __initdata = {
 850         .time_init = xen_time_init,
 851
 852         .set_wallclock = xen_set_wallclock,
 853         .get_wallclock = xen_get_wallclock,
 854         .get_tsc_khz = xen_tsc_khz,
 855         .sched_clock = xen_sched_clock,
 856 };
 857
 858 static const struct pv_cpu_ops xen_cpu_ops __initdata = {
 859         .cpuid = xen_cpuid,
 860
 861         .set_debugreg = xen_set_debugreg,
 862         .get_debugreg = xen_get_debugreg,
 863
 864         .clts = xen_clts,
 865
 866         .read_cr0 = xen_read_cr0,
 867         .write_cr0 = xen_write_cr0,
 868
 869         .read_cr4 = native_read_cr4,
 870         .read_cr4_safe = native_read_cr4_safe,
 871         .write_cr4 = xen_write_cr4,
 872
 873         .wbinvd = native_wbinvd,
 874
 875         .read_msr = native_read_msr_safe,
 876         .write_msr = xen_write_msr_safe,
 877         .read_tsc = native_read_tsc,
 878         .read_pmc = native_read_pmc,
 879
 880         .iret = xen_iret,
 881         .irq_enable_sysexit = xen_sysexit,
 882 #ifdef CONFIG_X86_64
 883         .usergs_sysret32 = xen_sysret32,
 884         .usergs_sysret64 = xen_sysret64,
 885 #endif
 886
 887         .load_tr_desc = paravirt_nop,
 888         .set_ldt = xen_set_ldt,
 889         .load_gdt = xen_load_gdt,
 890         .load_idt = xen_load_idt,
 891         .load_tls = xen_load_tls,
 892 #ifdef CONFIG_X86_64
 893         .load_gs_index = xen_load_gs_index,
 894 #endif
 895
 896         .alloc_ldt = xen_alloc_ldt,
 897         .free_ldt = xen_free_ldt,
 898
 899         .store_gdt = native_store_gdt,
 900         .store_idt = native_store_idt,
 901         .store_tr = xen_store_tr,
 902
 903         .write_ldt_entry = xen_write_ldt_entry,
 904         .write_gdt_entry = xen_write_gdt_entry,
 905         .write_idt_entry = xen_write_idt_entry,
 906         .load_sp0 = xen_load_sp0,
 907
 908         .set_iopl_mask = xen_set_iopl_mask,
 909         .io_delay = xen_io_delay,
 910
 911         /* Xen takes care of %gs when switching to usermode for us */
 912         .swapgs = paravirt_nop,
 913
 914         .start_context_switch = paravirt_start_context_switch,
 915         .end_context_switch = xen_end_context_switch,
 916 };
 917
 918 static const struct pv_apic_ops xen_apic_ops __initdata = {
 919 #ifdef CONFIG_X86_LOCAL_APIC
 920         .setup_boot_clock = paravirt_nop,
 921         .setup_secondary_clock = paravirt_nop,
 922         .startup_ipi_hook = paravirt_nop,
 923 #endif
 924 };
 925
 926 static void xen_reboot(int reason)
 927 {
 928         struct sched_shutdown r = { .reason = reason };
 929
 930 #ifdef CONFIG_SMP
 931         smp_send_stop();
 932 #endif
 933
 934         if (HYPERVISOR_sched_op(SCHEDOP_shutdown, &r))
 935                 BUG();
 936 }
 937
 938 static void xen_restart(char *msg)
 939 {
 940         xen_reboot(SHUTDOWN_reboot);
 941 }
 942
 943 static void xen_emergency_restart(void)
 944 {
 945         xen_reboot(SHUTDOWN_reboot);
 946 }
 947
 948 static void xen_machine_halt(void)
 949 {
 950         xen_reboot(SHUTDOWN_poweroff);
 951 }
 952
 953 static void xen_crash_shutdown(struct pt_regs *regs)
 954 {
 955         xen_reboot(SHUTDOWN_crash);
 956 }
 957
 958 static const struct machine_ops __initdata xen_machine_ops = {
 959         .restart = xen_restart,
 960         .halt = xen_machine_halt,
 961         .power_off = xen_machine_halt,
 962         .shutdown = xen_machine_halt,
 963         .crash_shutdown = xen_crash_shutdown,
 964         .emergency_restart = xen_emergency_restart,
 965 };
 966
 967 /* First C function to be called on Xen boot */
 968 asmlinkage void __init xen_start_kernel(void)
 969 {
 970         pgd_t *pgd;
 971
 972         if (!xen_start_info)
 973                 return;
 974
 975         xen_domain_type = XEN_PV_DOMAIN;
 976
 977         /* Install Xen paravirt ops */
 978         pv_info = xen_info;
 979         pv_init_ops = xen_init_ops;
 980         pv_time_ops = xen_time_ops;
 981         pv_cpu_ops = xen_cpu_ops;
 982         pv_apic_ops = xen_apic_ops;
 983         pv_mmu_ops = xen_mmu_ops;
 984
 985 #ifdef CONFIG_X86_64
 986         /*
 987          * Setup percpu state.  We only need to do this for 64-bit
 988          * because 32-bit already has %fs set properly.
 989          */
 990         load_percpu_segment(0);
 991 #endif
 992
 993         xen_init_irq_ops();
 994         xen_init_cpuid_mask();
 995
 996 #ifdef CONFIG_X86_LOCAL_APIC
 997         /*
 998          * set up the basic apic ops.
 999          */
1000         set_xen_basic_apic_ops();
1001 #endif
1002
1003         xen_setup_features();
1004
1005         if (xen_feature(XENFEAT_mmu_pt_update_preserve_ad)) {
1006                 pv_mmu_ops.ptep_modify_prot_start = xen_ptep_modify_prot_start;
1007                 pv_mmu_ops.ptep_modify_prot_commit = xen_ptep_modify_prot_commit;
1008         }
1009
1010         machine_ops = xen_machine_ops;
1011
1012         /*
1013          * The only reliable way to retain the initial address of the
1014          * percpu gdt_page is to remember it here, so we can go and
1015          * mark it RW later, when the initial percpu area is freed.
1016          */
1017         xen_initial_gdt = &per_cpu(gdt_page, 0);
1018
1019         xen_smp_init();
1020
1021         /* Get mfn list */
1022         if (!xen_feature(XENFEAT_auto_translated_physmap))
1023                 xen_build_dynamic_phys_to_machine();
1024
1025         pgd = (pgd_t *)xen_start_info->pt_base;
1026
1027         /* Prevent unwanted bits from being set in PTEs. */
1028         __supported_pte_mask &= ~_PAGE_GLOBAL;
1029         if (!xen_initial_domain())
1030                 __supported_pte_mask &= ~(_PAGE_PWT | _PAGE_PCD);
1031
1032 #ifdef CONFIG_X86_64
1033         /* Work out if we support NX */
1034         check_efer();
1035 #endif
1036
1037         /* Don't do the full vcpu_info placement stuff until we have a
1038            possible map and a non-dummy shared_info. */
1039         per_cpu(xen_vcpu, 0) = &HYPERVISOR_shared_info->vcpu_info[0];
1040
1041         local_irq_disable();
1042         early_boot_irqs_off();
1043
1044         xen_raw_console_write("mapping kernel into physical memory\n");
1045         pgd = xen_setup_kernel_pagetable(pgd, xen_start_info->nr_pages);
1046
1047         init_mm.pgd = pgd;
1048
1049         /* keep using Xen gdt for now; no urgent need to change it */
1050
1051         pv_info.kernel_rpl = 1;
1052         if (xen_feature(XENFEAT_supervisor_mode_kernel))
1053                 pv_info.kernel_rpl = 0;
1054
1055         /* set the limit of our address space */
1056         xen_reserve_top();
1057
1058 #ifdef CONFIG_X86_32
1059         /* set up basic CPUID stuff */
1060         cpu_detect(&new_cpu_data);
1061         new_cpu_data.hard_math = 1;
1062         new_cpu_data.x86_capability[0] = cpuid_edx(1);
1063 #endif
1064
1065         /* Poke various useful things into boot_params */
1066         boot_params.hdr.type_of_loader = (9 << 4) | 0;
1067         boot_params.hdr.ramdisk_image = xen_start_info->mod_start
1068                 ? __pa(xen_start_info->mod_start) : 0;
1069         boot_params.hdr.ramdisk_size = xen_start_info->mod_len;
1070         boot_params.hdr.cmd_line_ptr = __pa(xen_start_info->cmd_line);
1071
1072         if (!xen_initial_domain()) {
1073                 add_preferred_console("xenboot", 0, NULL);
1074                 add_preferred_console("tty", 0, NULL);
1075                 add_preferred_console("hvc", 0, NULL);
1076         }
1077
1078         xen_raw_console_write("about to get started...\n");
1079
1080         /* Start the world */
1081 #ifdef CONFIG_X86_32
1082         i386_start_kernel();
1083 #else
1084         x86_64_start_reservations((char *)__pa_symbol(&boot_params));
1085 #endif
1086 }