linux/arch/x86/xen/enlighten.c
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   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/console.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#include <xen/hvc-console.h>
  37
  38#include <asm/paravirt.h>
  39#include <asm/page.h>
  40#include <asm/xen/hypercall.h>
  41#include <asm/xen/hypervisor.h>
  42#include <asm/fixmap.h>
  43#include <asm/processor.h>
  44#include <asm/msr-index.h>
  45#include <asm/setup.h>
  46#include <asm/desc.h>
  47#include <asm/pgtable.h>
  48#include <asm/tlbflush.h>
  49#include <asm/reboot.h>
  50
  51#include "xen-ops.h"
  52#include "mmu.h"
  53#include "multicalls.h"
  54
  55EXPORT_SYMBOL_GPL(hypercall_page);
  56
  57DEFINE_PER_CPU(struct vcpu_info *, xen_vcpu);
  58DEFINE_PER_CPU(struct vcpu_info, xen_vcpu_info);
  59
  60/*
  61 * Identity map, in addition to plain kernel map.  This needs to be
  62 * large enough to allocate page table pages to allocate the rest.
  63 * Each page can map 2MB.
  64 */
  65static pte_t level1_ident_pgt[PTRS_PER_PTE * 4] __page_aligned_bss;
  66
  67#ifdef CONFIG_X86_64
  68/* l3 pud for userspace vsyscall mapping */
  69static pud_t level3_user_vsyscall[PTRS_PER_PUD] __page_aligned_bss;
  70#endif /* CONFIG_X86_64 */
  71
  72/*
  73 * Note about cr3 (pagetable base) values:
  74 *
  75 * xen_cr3 contains the current logical cr3 value; it contains the
  76 * last set cr3.  This may not be the current effective cr3, because
  77 * its update may be being lazily deferred.  However, a vcpu looking
  78 * at its own cr3 can use this value knowing that it everything will
  79 * be self-consistent.
  80 *
  81 * xen_current_cr3 contains the actual vcpu cr3; it is set once the
  82 * hypercall to set the vcpu cr3 is complete (so it may be a little
  83 * out of date, but it will never be set early).  If one vcpu is
  84 * looking at another vcpu's cr3 value, it should use this variable.
  85 */
  86DEFINE_PER_CPU(unsigned long, xen_cr3);  /* cr3 stored as physaddr */
  87DEFINE_PER_CPU(unsigned long, xen_current_cr3);  /* actual vcpu cr3 */
  88
  89struct start_info *xen_start_info;
  90EXPORT_SYMBOL_GPL(xen_start_info);
  91
  92struct shared_info xen_dummy_shared_info;
  93
  94/*
  95 * Point at some empty memory to start with. We map the real shared_info
  96 * page as soon as fixmap is up and running.
  97 */
  98struct shared_info *HYPERVISOR_shared_info = (void *)&xen_dummy_shared_info;
  99
 100/*
 101 * Flag to determine whether vcpu info placement is available on all
 102 * VCPUs.  We assume it is to start with, and then set it to zero on
 103 * the first failure.  This is because it can succeed on some VCPUs
 104 * and not others, since it can involve hypervisor memory allocation,
 105 * or because the guest failed to guarantee all the appropriate
 106 * constraints on all VCPUs (ie buffer can't cross a page boundary).
 107 *
 108 * Note that any particular CPU may be using a placed vcpu structure,
 109 * but we can only optimise if the all are.
 110 *
 111 * 0: not available, 1: available
 112 */
 113static int have_vcpu_info_placement = 1;
 114
 115static void xen_vcpu_setup(int cpu)
 116{
 117        struct vcpu_register_vcpu_info info;
 118        int err;
 119        struct vcpu_info *vcpup;
 120
 121        BUG_ON(HYPERVISOR_shared_info == &xen_dummy_shared_info);
 122        per_cpu(xen_vcpu, cpu) = &HYPERVISOR_shared_info->vcpu_info[cpu];
 123
 124        if (!have_vcpu_info_placement)
 125                return;         /* already tested, not available */
 126
 127        vcpup = &per_cpu(xen_vcpu_info, cpu);
 128
 129        info.mfn = virt_to_mfn(vcpup);
 130        info.offset = offset_in_page(vcpup);
 131
 132        printk(KERN_DEBUG "trying to map vcpu_info %d at %p, mfn %llx, offset %d\n",
 133               cpu, vcpup, info.mfn, info.offset);
 134
 135        /* Check to see if the hypervisor will put the vcpu_info
 136           structure where we want it, which allows direct access via
 137           a percpu-variable. */
 138        err = HYPERVISOR_vcpu_op(VCPUOP_register_vcpu_info, cpu, &info);
 139
 140        if (err) {
 141                printk(KERN_DEBUG "register_vcpu_info failed: err=%d\n", err);
 142                have_vcpu_info_placement = 0;
 143        } else {
 144                /* This cpu is using the registered vcpu info, even if
 145                   later ones fail to. */
 146                per_cpu(xen_vcpu, cpu) = vcpup;
 147
 148                printk(KERN_DEBUG "cpu %d using vcpu_info at %p\n",
 149                       cpu, vcpup);
 150        }
 151}
 152
 153/*
 154 * On restore, set the vcpu placement up again.
 155 * If it fails, then we're in a bad state, since
 156 * we can't back out from using it...
 157 */
 158void xen_vcpu_restore(void)
 159{
 160        if (have_vcpu_info_placement) {
 161                int cpu;
 162
 163                for_each_online_cpu(cpu) {
 164                        bool other_cpu = (cpu != smp_processor_id());
 165
 166                        if (other_cpu &&
 167                            HYPERVISOR_vcpu_op(VCPUOP_down, cpu, NULL))
 168                                BUG();
 169
 170                        xen_vcpu_setup(cpu);
 171
 172                        if (other_cpu &&
 173                            HYPERVISOR_vcpu_op(VCPUOP_up, cpu, NULL))
 174                                BUG();
 175                }
 176
 177                BUG_ON(!have_vcpu_info_placement);
 178        }
 179}
 180
 181static void __init xen_banner(void)
 182{
 183        unsigned version = HYPERVISOR_xen_version(XENVER_version, NULL);
 184        struct xen_extraversion extra;
 185        HYPERVISOR_xen_version(XENVER_extraversion, &extra);
 186
 187        printk(KERN_INFO "Booting paravirtualized kernel on %s\n",
 188               pv_info.name);
 189        printk(KERN_INFO "Xen version: %d.%d%s%s\n",
 190               version >> 16, version & 0xffff, extra.extraversion,
 191               xen_feature(XENFEAT_mmu_pt_update_preserve_ad) ? " (preserve-AD)" : "");
 192}
 193
 194static void xen_cpuid(unsigned int *ax, unsigned int *bx,
 195                      unsigned int *cx, unsigned int *dx)
 196{
 197        unsigned maskedx = ~0;
 198
 199        /*
 200         * Mask out inconvenient features, to try and disable as many
 201         * unsupported kernel subsystems as possible.
 202         */
 203        if (*ax == 1)
 204                maskedx = ~((1 << X86_FEATURE_APIC) |  /* disable APIC */
 205                            (1 << X86_FEATURE_ACPI) |  /* disable ACPI */
 206                            (1 << X86_FEATURE_MCE)  |  /* disable MCE */
 207                            (1 << X86_FEATURE_MCA)  |  /* disable MCA */
 208                            (1 << X86_FEATURE_ACC));   /* thermal monitoring */
 209
 210        asm(XEN_EMULATE_PREFIX "cpuid"
 211                : "=a" (*ax),
 212                  "=b" (*bx),
 213                  "=c" (*cx),
 214                  "=d" (*dx)
 215                : "0" (*ax), "2" (*cx));
 216        *dx &= maskedx;
 217}
 218
 219static void xen_set_debugreg(int reg, unsigned long val)
 220{
 221        HYPERVISOR_set_debugreg(reg, val);
 222}
 223
 224static unsigned long xen_get_debugreg(int reg)
 225{
 226        return HYPERVISOR_get_debugreg(reg);
 227}
 228
 229static unsigned long xen_save_fl(void)
 230{
 231        struct vcpu_info *vcpu;
 232        unsigned long flags;
 233
 234        vcpu = x86_read_percpu(xen_vcpu);
 235
 236        /* flag has opposite sense of mask */
 237        flags = !vcpu->evtchn_upcall_mask;
 238
 239        /* convert to IF type flag
 240           -0 -> 0x00000000
 241           -1 -> 0xffffffff
 242        */
 243        return (-flags) & X86_EFLAGS_IF;
 244}
 245
 246static void xen_restore_fl(unsigned long flags)
 247{
 248        struct vcpu_info *vcpu;
 249
 250        /* convert from IF type flag */
 251        flags = !(flags & X86_EFLAGS_IF);
 252
 253        /* There's a one instruction preempt window here.  We need to
 254           make sure we're don't switch CPUs between getting the vcpu
 255           pointer and updating the mask. */
 256        preempt_disable();
 257        vcpu = x86_read_percpu(xen_vcpu);
 258        vcpu->evtchn_upcall_mask = flags;
 259        preempt_enable_no_resched();
 260
 261        /* Doesn't matter if we get preempted here, because any
 262           pending event will get dealt with anyway. */
 263
 264        if (flags == 0) {
 265                preempt_check_resched();
 266                barrier(); /* unmask then check (avoid races) */
 267                if (unlikely(vcpu->evtchn_upcall_pending))
 268                        force_evtchn_callback();
 269        }
 270}
 271
 272static void xen_irq_disable(void)
 273{
 274        /* There's a one instruction preempt window here.  We need to
 275           make sure we're don't switch CPUs between getting the vcpu
 276           pointer and updating the mask. */
 277        preempt_disable();
 278        x86_read_percpu(xen_vcpu)->evtchn_upcall_mask = 1;
 279        preempt_enable_no_resched();
 280}
 281
 282static void xen_irq_enable(void)
 283{
 284        struct vcpu_info *vcpu;
 285
 286        /* We don't need to worry about being preempted here, since
 287           either a) interrupts are disabled, so no preemption, or b)
 288           the caller is confused and is trying to re-enable interrupts
 289           on an indeterminate processor. */
 290
 291        vcpu = x86_read_percpu(xen_vcpu);
 292        vcpu->evtchn_upcall_mask = 0;
 293
 294        /* Doesn't matter if we get preempted here, because any
 295           pending event will get dealt with anyway. */
 296
 297        barrier(); /* unmask then check (avoid races) */
 298        if (unlikely(vcpu->evtchn_upcall_pending))
 299                force_evtchn_callback();
 300}
 301
 302static void xen_safe_halt(void)
 303{
 304        /* Blocking includes an implicit local_irq_enable(). */
 305        if (HYPERVISOR_sched_op(SCHEDOP_block, NULL) != 0)
 306                BUG();
 307}
 308
 309static void xen_halt(void)
 310{
 311        if (irqs_disabled())
 312                HYPERVISOR_vcpu_op(VCPUOP_down, smp_processor_id(), NULL);
 313        else
 314                xen_safe_halt();
 315}
 316
 317static void xen_leave_lazy(void)
 318{
 319        paravirt_leave_lazy(paravirt_get_lazy_mode());
 320        xen_mc_flush();
 321}
 322
 323static unsigned long xen_store_tr(void)
 324{
 325        return 0;
 326}
 327
 328static void xen_set_ldt(const void *addr, unsigned entries)
 329{
 330        struct mmuext_op *op;
 331        struct multicall_space mcs = xen_mc_entry(sizeof(*op));
 332
 333        op = mcs.args;
 334        op->cmd = MMUEXT_SET_LDT;
 335        op->arg1.linear_addr = (unsigned long)addr;
 336        op->arg2.nr_ents = entries;
 337
 338        MULTI_mmuext_op(mcs.mc, op, 1, NULL, DOMID_SELF);
 339
 340        xen_mc_issue(PARAVIRT_LAZY_CPU);
 341}
 342
 343static void xen_load_gdt(const struct desc_ptr *dtr)
 344{
 345        unsigned long *frames;
 346        unsigned long va = dtr->address;
 347        unsigned int size = dtr->size + 1;
 348        unsigned pages = (size + PAGE_SIZE - 1) / PAGE_SIZE;
 349        int f;
 350        struct multicall_space mcs;
 351
 352        /* A GDT can be up to 64k in size, which corresponds to 8192
 353           8-byte entries, or 16 4k pages.. */
 354
 355        BUG_ON(size > 65536);
 356        BUG_ON(va & ~PAGE_MASK);
 357
 358        mcs = xen_mc_entry(sizeof(*frames) * pages);
 359        frames = mcs.args;
 360
 361        for (f = 0; va < dtr->address + size; va += PAGE_SIZE, f++) {
 362                frames[f] = virt_to_mfn(va);
 363                make_lowmem_page_readonly((void *)va);
 364        }
 365
 366        MULTI_set_gdt(mcs.mc, frames, size / sizeof(struct desc_struct));
 367
 368        xen_mc_issue(PARAVIRT_LAZY_CPU);
 369}
 370
 371static void load_TLS_descriptor(struct thread_struct *t,
 372                                unsigned int cpu, unsigned int i)
 373{
 374        struct desc_struct *gdt = get_cpu_gdt_table(cpu);
 375        xmaddr_t maddr = virt_to_machine(&gdt[GDT_ENTRY_TLS_MIN+i]);
 376        struct multicall_space mc = __xen_mc_entry(0);
 377
 378        MULTI_update_descriptor(mc.mc, maddr.maddr, t->tls_array[i]);
 379}
 380
 381static void xen_load_tls(struct thread_struct *t, unsigned int cpu)
 382{
 383        /*
 384         * XXX sleazy hack: If we're being called in a lazy-cpu zone,
 385         * it means we're in a context switch, and %gs has just been
 386         * saved.  This means we can zero it out to prevent faults on
 387         * exit from the hypervisor if the next process has no %gs.
 388         * Either way, it has been saved, and the new value will get
 389         * loaded properly.  This will go away as soon as Xen has been
 390         * modified to not save/restore %gs for normal hypercalls.
 391         *
 392         * On x86_64, this hack is not used for %gs, because gs points
 393         * to KERNEL_GS_BASE (and uses it for PDA references), so we
 394         * must not zero %gs on x86_64
 395         *
 396         * For x86_64, we need to zero %fs, otherwise we may get an
 397         * exception between the new %fs descriptor being loaded and
 398         * %fs being effectively cleared at __switch_to().
 399         */
 400        if (paravirt_get_lazy_mode() == PARAVIRT_LAZY_CPU) {
 401#ifdef CONFIG_X86_32
 402                loadsegment(gs, 0);
 403#else
 404                loadsegment(fs, 0);
 405#endif
 406        }
 407
 408        xen_mc_batch();
 409
 410        load_TLS_descriptor(t, cpu, 0);
 411        load_TLS_descriptor(t, cpu, 1);
 412        load_TLS_descriptor(t, cpu, 2);
 413
 414        xen_mc_issue(PARAVIRT_LAZY_CPU);
 415}
 416
 417#ifdef CONFIG_X86_64
 418static void xen_load_gs_index(unsigned int idx)
 419{
 420        if (HYPERVISOR_set_segment_base(SEGBASE_GS_USER_SEL, idx))
 421                BUG();
 422}
 423#endif
 424
 425static void xen_write_ldt_entry(struct desc_struct *dt, int entrynum,
 426                                const void *ptr)
 427{
 428        unsigned long lp = (unsigned long)&dt[entrynum];
 429        xmaddr_t mach_lp = virt_to_machine(lp);
 430        u64 entry = *(u64 *)ptr;
 431
 432        preempt_disable();
 433
 434        xen_mc_flush();
 435        if (HYPERVISOR_update_descriptor(mach_lp.maddr, entry))
 436                BUG();
 437
 438        preempt_enable();
 439}
 440
 441static int cvt_gate_to_trap(int vector, const gate_desc *val,
 442                            struct trap_info *info)
 443{
 444        if (val->type != 0xf && val->type != 0xe)
 445                return 0;
 446
 447        info->vector = vector;
 448        info->address = gate_offset(*val);
 449        info->cs = gate_segment(*val);
 450        info->flags = val->dpl;
 451        /* interrupt gates clear IF */
 452        if (val->type == 0xe)
 453                info->flags |= 4;
 454
 455        return 1;
 456}
 457
 458/* Locations of each CPU's IDT */
 459static DEFINE_PER_CPU(struct desc_ptr, idt_desc);
 460
 461/* Set an IDT entry.  If the entry is part of the current IDT, then
 462   also update Xen. */
 463static void xen_write_idt_entry(gate_desc *dt, int entrynum, const gate_desc *g)
 464{
 465        unsigned long p = (unsigned long)&dt[entrynum];
 466        unsigned long start, end;
 467
 468        preempt_disable();
 469
 470        start = __get_cpu_var(idt_desc).address;
 471        end = start + __get_cpu_var(idt_desc).size + 1;
 472
 473        xen_mc_flush();
 474
 475        native_write_idt_entry(dt, entrynum, g);
 476
 477        if (p >= start && (p + 8) <= end) {
 478                struct trap_info info[2];
 479
 480                info[1].address = 0;
 481
 482                if (cvt_gate_to_trap(entrynum, g, &info[0]))
 483                        if (HYPERVISOR_set_trap_table(info))
 484                                BUG();
 485        }
 486
 487        preempt_enable();
 488}
 489
 490static void xen_convert_trap_info(const struct desc_ptr *desc,
 491                                  struct trap_info *traps)
 492{
 493        unsigned in, out, count;
 494
 495        count = (desc->size+1) / sizeof(gate_desc);
 496        BUG_ON(count > 256);
 497
 498        for (in = out = 0; in < count; in++) {
 499                gate_desc *entry = (gate_desc*)(desc->address) + in;
 500
 501                if (cvt_gate_to_trap(in, entry, &traps[out]))
 502                        out++;
 503        }
 504        traps[out].address = 0;
 505}
 506
 507void xen_copy_trap_info(struct trap_info *traps)
 508{
 509        const struct desc_ptr *desc = &__get_cpu_var(idt_desc);
 510
 511        xen_convert_trap_info(desc, traps);
 512}
 513
 514/* Load a new IDT into Xen.  In principle this can be per-CPU, so we
 515   hold a spinlock to protect the static traps[] array (static because
 516   it avoids allocation, and saves stack space). */
 517static void xen_load_idt(const struct desc_ptr *desc)
 518{
 519        static DEFINE_SPINLOCK(lock);
 520        static struct trap_info traps[257];
 521
 522        spin_lock(&lock);
 523
 524        __get_cpu_var(idt_desc) = *desc;
 525
 526        xen_convert_trap_info(desc, traps);
 527
 528        xen_mc_flush();
 529        if (HYPERVISOR_set_trap_table(traps))
 530                BUG();
 531
 532        spin_unlock(&lock);
 533}
 534
 535/* Write a GDT descriptor entry.  Ignore LDT descriptors, since
 536   they're handled differently. */
 537static void xen_write_gdt_entry(struct desc_struct *dt, int entry,
 538                                const void *desc, int type)
 539{
 540        preempt_disable();
 541
 542        switch (type) {
 543        case DESC_LDT:
 544        case DESC_TSS:
 545                /* ignore */
 546                break;
 547
 548        default: {
 549                xmaddr_t maddr = virt_to_machine(&dt[entry]);
 550
 551                xen_mc_flush();
 552                if (HYPERVISOR_update_descriptor(maddr.maddr, *(u64 *)desc))
 553                        BUG();
 554        }
 555
 556        }
 557
 558        preempt_enable();
 559}
 560
 561static void xen_load_sp0(struct tss_struct *tss,
 562                          struct thread_struct *thread)
 563{
 564        struct multicall_space mcs = xen_mc_entry(0);
 565        MULTI_stack_switch(mcs.mc, __KERNEL_DS, thread->sp0);
 566        xen_mc_issue(PARAVIRT_LAZY_CPU);
 567}
 568
 569static void xen_set_iopl_mask(unsigned mask)
 570{
 571        struct physdev_set_iopl set_iopl;
 572
 573        /* Force the change at ring 0. */
 574        set_iopl.iopl = (mask == 0) ? 1 : (mask >> 12) & 3;
 575        HYPERVISOR_physdev_op(PHYSDEVOP_set_iopl, &set_iopl);
 576}
 577
 578static void xen_io_delay(void)
 579{
 580}
 581
 582#ifdef CONFIG_X86_LOCAL_APIC
 583static u32 xen_apic_read(unsigned long reg)
 584{
 585        return 0;
 586}
 587
 588static void xen_apic_write(unsigned long reg, u32 val)
 589{
 590        /* Warn to see if there's any stray references */
 591        WARN_ON(1);
 592}
 593#endif
 594
 595static void xen_flush_tlb(void)
 596{
 597        struct mmuext_op *op;
 598        struct multicall_space mcs;
 599
 600        preempt_disable();
 601
 602        mcs = xen_mc_entry(sizeof(*op));
 603
 604        op = mcs.args;
 605        op->cmd = MMUEXT_TLB_FLUSH_LOCAL;
 606        MULTI_mmuext_op(mcs.mc, op, 1, NULL, DOMID_SELF);
 607
 608        xen_mc_issue(PARAVIRT_LAZY_MMU);
 609
 610        preempt_enable();
 611}
 612
 613static void xen_flush_tlb_single(unsigned long addr)
 614{
 615        struct mmuext_op *op;
 616        struct multicall_space mcs;
 617
 618        preempt_disable();
 619
 620        mcs = xen_mc_entry(sizeof(*op));
 621        op = mcs.args;
 622        op->cmd = MMUEXT_INVLPG_LOCAL;
 623        op->arg1.linear_addr = addr & PAGE_MASK;
 624        MULTI_mmuext_op(mcs.mc, op, 1, NULL, DOMID_SELF);
 625
 626        xen_mc_issue(PARAVIRT_LAZY_MMU);
 627
 628        preempt_enable();
 629}
 630
 631static void xen_flush_tlb_others(const cpumask_t *cpus, struct mm_struct *mm,
 632                                 unsigned long va)
 633{
 634        struct {
 635                struct mmuext_op op;
 636                cpumask_t mask;
 637        } *args;
 638        cpumask_t cpumask = *cpus;
 639        struct multicall_space mcs;
 640
 641        /*
 642         * A couple of (to be removed) sanity checks:
 643         *
 644         * - current CPU must not be in mask
 645         * - mask must exist :)
 646         */
 647        BUG_ON(cpus_empty(cpumask));
 648        BUG_ON(cpu_isset(smp_processor_id(), cpumask));
 649        BUG_ON(!mm);
 650
 651        /* If a CPU which we ran on has gone down, OK. */
 652        cpus_and(cpumask, cpumask, cpu_online_map);
 653        if (cpus_empty(cpumask))
 654                return;
 655
 656        mcs = xen_mc_entry(sizeof(*args));
 657        args = mcs.args;
 658        args->mask = cpumask;
 659        args->op.arg2.vcpumask = &args->mask;
 660
 661        if (va == TLB_FLUSH_ALL) {
 662                args->op.cmd = MMUEXT_TLB_FLUSH_MULTI;
 663        } else {
 664                args->op.cmd = MMUEXT_INVLPG_MULTI;
 665                args->op.arg1.linear_addr = va;
 666        }
 667
 668        MULTI_mmuext_op(mcs.mc, &args->op, 1, NULL, DOMID_SELF);
 669
 670        xen_mc_issue(PARAVIRT_LAZY_MMU);
 671}
 672
 673static void xen_clts(void)
 674{
 675        struct multicall_space mcs;
 676
 677        mcs = xen_mc_entry(0);
 678
 679        MULTI_fpu_taskswitch(mcs.mc, 0);
 680
 681        xen_mc_issue(PARAVIRT_LAZY_CPU);
 682}
 683
 684static void xen_write_cr0(unsigned long cr0)
 685{
 686        struct multicall_space mcs;
 687
 688        /* Only pay attention to cr0.TS; everything else is
 689           ignored. */
 690        mcs = xen_mc_entry(0);
 691
 692        MULTI_fpu_taskswitch(mcs.mc, (cr0 & X86_CR0_TS) != 0);
 693
 694        xen_mc_issue(PARAVIRT_LAZY_CPU);
 695}
 696
 697static void xen_write_cr2(unsigned long cr2)
 698{
 699        x86_read_percpu(xen_vcpu)->arch.cr2 = cr2;
 700}
 701
 702static unsigned long xen_read_cr2(void)
 703{
 704        return x86_read_percpu(xen_vcpu)->arch.cr2;
 705}
 706
 707static unsigned long xen_read_cr2_direct(void)
 708{
 709        return x86_read_percpu(xen_vcpu_info.arch.cr2);
 710}
 711
 712static void xen_write_cr4(unsigned long cr4)
 713{
 714        cr4 &= ~X86_CR4_PGE;
 715        cr4 &= ~X86_CR4_PSE;
 716
 717        native_write_cr4(cr4);
 718}
 719
 720static unsigned long xen_read_cr3(void)
 721{
 722        return x86_read_percpu(xen_cr3);
 723}
 724
 725static void set_current_cr3(void *v)
 726{
 727        x86_write_percpu(xen_current_cr3, (unsigned long)v);
 728}
 729
 730static void __xen_write_cr3(bool kernel, unsigned long cr3)
 731{
 732        struct mmuext_op *op;
 733        struct multicall_space mcs;
 734        unsigned long mfn;
 735
 736        if (cr3)
 737                mfn = pfn_to_mfn(PFN_DOWN(cr3));
 738        else
 739                mfn = 0;
 740
 741        WARN_ON(mfn == 0 && kernel);
 742
 743        mcs = __xen_mc_entry(sizeof(*op));
 744
 745        op = mcs.args;
 746        op->cmd = kernel ? MMUEXT_NEW_BASEPTR : MMUEXT_NEW_USER_BASEPTR;
 747        op->arg1.mfn = mfn;
 748
 749        MULTI_mmuext_op(mcs.mc, op, 1, NULL, DOMID_SELF);
 750
 751        if (kernel) {
 752                x86_write_percpu(xen_cr3, cr3);
 753
 754                /* Update xen_current_cr3 once the batch has actually
 755                   been submitted. */
 756                xen_mc_callback(set_current_cr3, (void *)cr3);
 757        }
 758}
 759
 760static void xen_write_cr3(unsigned long cr3)
 761{
 762        BUG_ON(preemptible());
 763
 764        xen_mc_batch();  /* disables interrupts */
 765
 766        /* Update while interrupts are disabled, so its atomic with
 767           respect to ipis */
 768        x86_write_percpu(xen_cr3, cr3);
 769
 770        __xen_write_cr3(true, cr3);
 771
 772#ifdef CONFIG_X86_64
 773        {
 774                pgd_t *user_pgd = xen_get_user_pgd(__va(cr3));
 775                if (user_pgd)
 776                        __xen_write_cr3(false, __pa(user_pgd));
 777                else
 778                        __xen_write_cr3(false, 0);
 779        }
 780#endif
 781
 782        xen_mc_issue(PARAVIRT_LAZY_CPU);  /* interrupts restored */
 783}
 784
 785static int xen_write_msr_safe(unsigned int msr, unsigned low, unsigned high)
 786{
 787        int ret;
 788
 789        ret = 0;
 790
 791        switch(msr) {
 792#ifdef CONFIG_X86_64
 793                unsigned which;
 794                u64 base;
 795
 796        case MSR_FS_BASE:               which = SEGBASE_FS; goto set;
 797        case MSR_KERNEL_GS_BASE:        which = SEGBASE_GS_USER; goto set;
 798        case MSR_GS_BASE:               which = SEGBASE_GS_KERNEL; goto set;
 799
 800        set:
 801                base = ((u64)high << 32) | low;
 802                if (HYPERVISOR_set_segment_base(which, base) != 0)
 803                        ret = -EFAULT;
 804                break;
 805#endif
 806        default:
 807                ret = native_write_msr_safe(msr, low, high);
 808        }
 809
 810        return ret;
 811}
 812
 813/* Early in boot, while setting up the initial pagetable, assume
 814   everything is pinned. */
 815static __init void xen_alloc_pte_init(struct mm_struct *mm, u32 pfn)
 816{
 817#ifdef CONFIG_FLATMEM
 818        BUG_ON(mem_map);        /* should only be used early */
 819#endif
 820        make_lowmem_page_readonly(__va(PFN_PHYS(pfn)));
 821}
 822
 823/* Early release_pte assumes that all pts are pinned, since there's
 824   only init_mm and anything attached to that is pinned. */
 825static void xen_release_pte_init(u32 pfn)
 826{
 827        make_lowmem_page_readwrite(__va(PFN_PHYS(pfn)));
 828}
 829
 830static void pin_pagetable_pfn(unsigned cmd, unsigned long pfn)
 831{
 832        struct mmuext_op op;
 833        op.cmd = cmd;
 834        op.arg1.mfn = pfn_to_mfn(pfn);
 835        if (HYPERVISOR_mmuext_op(&op, 1, NULL, DOMID_SELF))
 836                BUG();
 837}
 838
 839/* This needs to make sure the new pte page is pinned iff its being
 840   attached to a pinned pagetable. */
 841static void xen_alloc_ptpage(struct mm_struct *mm, u32 pfn, unsigned level)
 842{
 843        struct page *page = pfn_to_page(pfn);
 844
 845        if (PagePinned(virt_to_page(mm->pgd))) {
 846                SetPagePinned(page);
 847
 848                if (!PageHighMem(page)) {
 849                        make_lowmem_page_readonly(__va(PFN_PHYS(pfn)));
 850                        if (level == PT_PTE)
 851                                pin_pagetable_pfn(MMUEXT_PIN_L1_TABLE, pfn);
 852                } else
 853                        /* make sure there are no stray mappings of
 854                           this page */
 855                        kmap_flush_unused();
 856        }
 857}
 858
 859static void xen_alloc_pte(struct mm_struct *mm, u32 pfn)
 860{
 861        xen_alloc_ptpage(mm, pfn, PT_PTE);
 862}
 863
 864static void xen_alloc_pmd(struct mm_struct *mm, u32 pfn)
 865{
 866        xen_alloc_ptpage(mm, pfn, PT_PMD);
 867}
 868
 869static int xen_pgd_alloc(struct mm_struct *mm)
 870{
 871        pgd_t *pgd = mm->pgd;
 872        int ret = 0;
 873
 874        BUG_ON(PagePinned(virt_to_page(pgd)));
 875
 876#ifdef CONFIG_X86_64
 877        {
 878                struct page *page = virt_to_page(pgd);
 879                pgd_t *user_pgd;
 880
 881                BUG_ON(page->private != 0);
 882
 883                ret = -ENOMEM;
 884
 885                user_pgd = (pgd_t *)__get_free_page(GFP_KERNEL | __GFP_ZERO);
 886                page->private = (unsigned long)user_pgd;
 887
 888                if (user_pgd != NULL) {
 889                        user_pgd[pgd_index(VSYSCALL_START)] =
 890                                __pgd(__pa(level3_user_vsyscall) | _PAGE_TABLE);
 891                        ret = 0;
 892                }
 893
 894                BUG_ON(PagePinned(virt_to_page(xen_get_user_pgd(pgd))));
 895        }
 896#endif
 897
 898        return ret;
 899}
 900
 901static void xen_pgd_free(struct mm_struct *mm, pgd_t *pgd)
 902{
 903#ifdef CONFIG_X86_64
 904        pgd_t *user_pgd = xen_get_user_pgd(pgd);
 905
 906        if (user_pgd)
 907                free_page((unsigned long)user_pgd);
 908#endif
 909}
 910
 911/* This should never happen until we're OK to use struct page */
 912static void xen_release_ptpage(u32 pfn, unsigned level)
 913{
 914        struct page *page = pfn_to_page(pfn);
 915
 916        if (PagePinned(page)) {
 917                if (!PageHighMem(page)) {
 918                        if (level == PT_PTE)
 919                                pin_pagetable_pfn(MMUEXT_UNPIN_TABLE, pfn);
 920                        make_lowmem_page_readwrite(__va(PFN_PHYS(pfn)));
 921                }
 922                ClearPagePinned(page);
 923        }
 924}
 925
 926static void xen_release_pte(u32 pfn)
 927{
 928        xen_release_ptpage(pfn, PT_PTE);
 929}
 930
 931static void xen_release_pmd(u32 pfn)
 932{
 933        xen_release_ptpage(pfn, PT_PMD);
 934}
 935
 936#if PAGETABLE_LEVELS == 4
 937static void xen_alloc_pud(struct mm_struct *mm, u32 pfn)
 938{
 939        xen_alloc_ptpage(mm, pfn, PT_PUD);
 940}
 941
 942static void xen_release_pud(u32 pfn)
 943{
 944        xen_release_ptpage(pfn, PT_PUD);
 945}
 946#endif
 947
 948#ifdef CONFIG_HIGHPTE
 949static void *xen_kmap_atomic_pte(struct page *page, enum km_type type)
 950{
 951        pgprot_t prot = PAGE_KERNEL;
 952
 953        if (PagePinned(page))
 954                prot = PAGE_KERNEL_RO;
 955
 956        if (0 && PageHighMem(page))
 957                printk("mapping highpte %lx type %d prot %s\n",
 958                       page_to_pfn(page), type,
 959                       (unsigned long)pgprot_val(prot) & _PAGE_RW ? "WRITE" : "READ");
 960
 961        return kmap_atomic_prot(page, type, prot);
 962}
 963#endif
 964
 965static __init pte_t mask_rw_pte(pte_t *ptep, pte_t pte)
 966{
 967        /* If there's an existing pte, then don't allow _PAGE_RW to be set */
 968        if (pte_val_ma(*ptep) & _PAGE_PRESENT)
 969                pte = __pte_ma(((pte_val_ma(*ptep) & _PAGE_RW) | ~_PAGE_RW) &
 970                               pte_val_ma(pte));
 971
 972        return pte;
 973}
 974
 975/* Init-time set_pte while constructing initial pagetables, which
 976   doesn't allow RO pagetable pages to be remapped RW */
 977static __init void xen_set_pte_init(pte_t *ptep, pte_t pte)
 978{
 979        pte = mask_rw_pte(ptep, pte);
 980
 981        xen_set_pte(ptep, pte);
 982}
 983
 984static __init void xen_pagetable_setup_start(pgd_t *base)
 985{
 986}
 987
 988void xen_setup_shared_info(void)
 989{
 990        if (!xen_feature(XENFEAT_auto_translated_physmap)) {
 991                set_fixmap(FIX_PARAVIRT_BOOTMAP,
 992                           xen_start_info->shared_info);
 993
 994                HYPERVISOR_shared_info =
 995                        (struct shared_info *)fix_to_virt(FIX_PARAVIRT_BOOTMAP);
 996        } else
 997                HYPERVISOR_shared_info =
 998                        (struct shared_info *)__va(xen_start_info->shared_info);
 999
1000#ifndef CONFIG_SMP
1001        /* In UP this is as good a place as any to set up shared info */
1002        xen_setup_vcpu_info_placement();
1003#endif
1004
1005        xen_setup_mfn_list_list();
1006}
1007
1008static __init void xen_pagetable_setup_done(pgd_t *base)
1009{
1010        xen_setup_shared_info();
1011}
1012
1013static __init void xen_post_allocator_init(void)
1014{
1015        pv_mmu_ops.set_pte = xen_set_pte;
1016        pv_mmu_ops.set_pmd = xen_set_pmd;
1017        pv_mmu_ops.set_pud = xen_set_pud;
1018#if PAGETABLE_LEVELS == 4
1019        pv_mmu_ops.set_pgd = xen_set_pgd;
1020#endif
1021
1022        /* This will work as long as patching hasn't happened yet
1023           (which it hasn't) */
1024        pv_mmu_ops.alloc_pte = xen_alloc_pte;
1025        pv_mmu_ops.alloc_pmd = xen_alloc_pmd;
1026        pv_mmu_ops.release_pte = xen_release_pte;
1027        pv_mmu_ops.release_pmd = xen_release_pmd;
1028#if PAGETABLE_LEVELS == 4
1029        pv_mmu_ops.alloc_pud = xen_alloc_pud;
1030        pv_mmu_ops.release_pud = xen_release_pud;
1031#endif
1032
1033#ifdef CONFIG_X86_64
1034        SetPagePinned(virt_to_page(level3_user_vsyscall));
1035#endif
1036        xen_mark_init_mm_pinned();
1037}
1038
1039/* This is called once we have the cpu_possible_map */
1040void xen_setup_vcpu_info_placement(void)
1041{
1042        int cpu;
1043
1044        for_each_possible_cpu(cpu)
1045                xen_vcpu_setup(cpu);
1046
1047        /* xen_vcpu_setup managed to place the vcpu_info within the
1048           percpu area for all cpus, so make use of it */
1049#ifdef CONFIG_X86_32
1050        if (have_vcpu_info_placement) {
1051                printk(KERN_INFO "Xen: using vcpu_info placement\n");
1052
1053                pv_irq_ops.save_fl = xen_save_fl_direct;
1054                pv_irq_ops.restore_fl = xen_restore_fl_direct;
1055                pv_irq_ops.irq_disable = xen_irq_disable_direct;
1056                pv_irq_ops.irq_enable = xen_irq_enable_direct;
1057                pv_mmu_ops.read_cr2 = xen_read_cr2_direct;
1058        }
1059#endif
1060}
1061
1062static unsigned xen_patch(u8 type, u16 clobbers, void *insnbuf,
1063                          unsigned long addr, unsigned len)
1064{
1065        char *start, *end, *reloc;
1066        unsigned ret;
1067
1068        start = end = reloc = NULL;
1069
1070#define SITE(op, x)                                                     \
1071        case PARAVIRT_PATCH(op.x):                                      \
1072        if (have_vcpu_info_placement) {                                 \
1073                start = (char *)xen_##x##_direct;                       \
1074                end = xen_##x##_direct_end;                             \
1075                reloc = xen_##x##_direct_reloc;                         \
1076        }                                                               \
1077        goto patch_site
1078
1079        switch (type) {
1080#ifdef CONFIG_X86_32
1081                SITE(pv_irq_ops, irq_enable);
1082                SITE(pv_irq_ops, irq_disable);
1083                SITE(pv_irq_ops, save_fl);
1084                SITE(pv_irq_ops, restore_fl);
1085#endif /* CONFIG_X86_32 */
1086#undef SITE
1087
1088        patch_site:
1089                if (start == NULL || (end-start) > len)
1090                        goto default_patch;
1091
1092                ret = paravirt_patch_insns(insnbuf, len, start, end);
1093
1094                /* Note: because reloc is assigned from something that
1095                   appears to be an array, gcc assumes it's non-null,
1096                   but doesn't know its relationship with start and
1097                   end. */
1098                if (reloc > start && reloc < end) {
1099                        int reloc_off = reloc - start;
1100                        long *relocp = (long *)(insnbuf + reloc_off);
1101                        long delta = start - (char *)addr;
1102
1103                        *relocp += delta;
1104                }
1105                break;
1106
1107        default_patch:
1108        default:
1109                ret = paravirt_patch_default(type, clobbers, insnbuf,
1110                                             addr, len);
1111                break;
1112        }
1113
1114        return ret;
1115}
1116
1117static void xen_set_fixmap(unsigned idx, unsigned long phys, pgprot_t prot)
1118{
1119        pte_t pte;
1120
1121        phys >>= PAGE_SHIFT;
1122
1123        switch (idx) {
1124        case FIX_BTMAP_END ... FIX_BTMAP_BEGIN:
1125#ifdef CONFIG_X86_F00F_BUG
1126        case FIX_F00F_IDT:
1127#endif
1128#ifdef CONFIG_X86_32
1129        case FIX_WP_TEST:
1130        case FIX_VDSO:
1131# ifdef CONFIG_HIGHMEM
1132        case FIX_KMAP_BEGIN ... FIX_KMAP_END:
1133# endif
1134#else
1135        case VSYSCALL_LAST_PAGE ... VSYSCALL_FIRST_PAGE:
1136#endif
1137#ifdef CONFIG_X86_LOCAL_APIC
1138        case FIX_APIC_BASE:     /* maps dummy local APIC */
1139#endif
1140                pte = pfn_pte(phys, prot);
1141                break;
1142
1143        default:
1144                pte = mfn_pte(phys, prot);
1145                break;
1146        }
1147
1148        __native_set_fixmap(idx, pte);
1149
1150#ifdef CONFIG_X86_64
1151        /* Replicate changes to map the vsyscall page into the user
1152           pagetable vsyscall mapping. */
1153        if (idx >= VSYSCALL_LAST_PAGE && idx <= VSYSCALL_FIRST_PAGE) {
1154                unsigned long vaddr = __fix_to_virt(idx);
1155                set_pte_vaddr_pud(level3_user_vsyscall, vaddr, pte);
1156        }
1157#endif
1158}
1159
1160static const struct pv_info xen_info __initdata = {
1161        .paravirt_enabled = 1,
1162        .shared_kernel_pmd = 0,
1163
1164        .name = "Xen",
1165};
1166
1167static const struct pv_init_ops xen_init_ops __initdata = {
1168        .patch = xen_patch,
1169
1170        .banner = xen_banner,
1171        .memory_setup = xen_memory_setup,
1172        .arch_setup = xen_arch_setup,
1173        .post_allocator_init = xen_post_allocator_init,
1174};
1175
1176static const struct pv_time_ops xen_time_ops __initdata = {
1177        .time_init = xen_time_init,
1178
1179        .set_wallclock = xen_set_wallclock,
1180        .get_wallclock = xen_get_wallclock,
1181        .get_tsc_khz = xen_tsc_khz,
1182        .sched_clock = xen_clocksource_read,
1183};
1184
1185static const struct pv_cpu_ops xen_cpu_ops __initdata = {
1186        .cpuid = xen_cpuid,
1187
1188        .set_debugreg = xen_set_debugreg,
1189        .get_debugreg = xen_get_debugreg,
1190
1191        .clts = xen_clts,
1192
1193        .read_cr0 = native_read_cr0,
1194        .write_cr0 = xen_write_cr0,
1195
1196        .read_cr4 = native_read_cr4,
1197        .read_cr4_safe = native_read_cr4_safe,
1198        .write_cr4 = xen_write_cr4,
1199
1200        .wbinvd = native_wbinvd,
1201
1202        .read_msr = native_read_msr_safe,
1203        .write_msr = xen_write_msr_safe,
1204        .read_tsc = native_read_tsc,
1205        .read_pmc = native_read_pmc,
1206
1207        .iret = xen_iret,
1208        .irq_enable_sysexit = xen_sysexit,
1209#ifdef CONFIG_X86_64
1210        .usergs_sysret32 = xen_sysret32,
1211        .usergs_sysret64 = xen_sysret64,
1212#endif
1213
1214        .load_tr_desc = paravirt_nop,
1215        .set_ldt = xen_set_ldt,
1216        .load_gdt = xen_load_gdt,
1217        .load_idt = xen_load_idt,
1218        .load_tls = xen_load_tls,
1219#ifdef CONFIG_X86_64
1220        .load_gs_index = xen_load_gs_index,
1221#endif
1222
1223        .store_gdt = native_store_gdt,
1224        .store_idt = native_store_idt,
1225        .store_tr = xen_store_tr,
1226
1227        .write_ldt_entry = xen_write_ldt_entry,
1228        .write_gdt_entry = xen_write_gdt_entry,
1229        .write_idt_entry = xen_write_idt_entry,
1230        .load_sp0 = xen_load_sp0,
1231
1232        .set_iopl_mask = xen_set_iopl_mask,
1233        .io_delay = xen_io_delay,
1234
1235        /* Xen takes care of %gs when switching to usermode for us */
1236        .swapgs = paravirt_nop,
1237
1238        .lazy_mode = {
1239                .enter = paravirt_enter_lazy_cpu,
1240                .leave = xen_leave_lazy,
1241        },
1242};
1243
1244static void __init __xen_init_IRQ(void)
1245{
1246#ifdef CONFIG_X86_64
1247        int i;
1248
1249        /* Create identity vector->irq map */
1250        for(i = 0; i < NR_VECTORS; i++) {
1251                int cpu;
1252
1253                for_each_possible_cpu(cpu)
1254                        per_cpu(vector_irq, cpu)[i] = i;
1255        }
1256#endif  /* CONFIG_X86_64 */
1257
1258        xen_init_IRQ();
1259}
1260
1261static const struct pv_irq_ops xen_irq_ops __initdata = {
1262        .init_IRQ = __xen_init_IRQ,
1263        .save_fl = xen_save_fl,
1264        .restore_fl = xen_restore_fl,
1265        .irq_disable = xen_irq_disable,
1266        .irq_enable = xen_irq_enable,
1267        .safe_halt = xen_safe_halt,
1268        .halt = xen_halt,
1269#ifdef CONFIG_X86_64
1270        .adjust_exception_frame = xen_adjust_exception_frame,
1271#endif
1272};
1273
1274static const struct pv_apic_ops xen_apic_ops __initdata = {
1275#ifdef CONFIG_X86_LOCAL_APIC
1276        .apic_write = xen_apic_write,
1277        .apic_read = xen_apic_read,
1278        .setup_boot_clock = paravirt_nop,
1279        .setup_secondary_clock = paravirt_nop,
1280        .startup_ipi_hook = paravirt_nop,
1281#endif
1282};
1283
1284static const struct pv_mmu_ops xen_mmu_ops __initdata = {
1285        .pagetable_setup_start = xen_pagetable_setup_start,
1286        .pagetable_setup_done = xen_pagetable_setup_done,
1287
1288        .read_cr2 = xen_read_cr2,
1289        .write_cr2 = xen_write_cr2,
1290
1291        .read_cr3 = xen_read_cr3,
1292        .write_cr3 = xen_write_cr3,
1293
1294        .flush_tlb_user = xen_flush_tlb,
1295        .flush_tlb_kernel = xen_flush_tlb,
1296        .flush_tlb_single = xen_flush_tlb_single,
1297        .flush_tlb_others = xen_flush_tlb_others,
1298
1299        .pte_update = paravirt_nop,
1300        .pte_update_defer = paravirt_nop,
1301
1302        .pgd_alloc = xen_pgd_alloc,
1303        .pgd_free = xen_pgd_free,
1304
1305        .alloc_pte = xen_alloc_pte_init,
1306        .release_pte = xen_release_pte_init,
1307        .alloc_pmd = xen_alloc_pte_init,
1308        .alloc_pmd_clone = paravirt_nop,
1309        .release_pmd = xen_release_pte_init,
1310
1311#ifdef CONFIG_HIGHPTE
1312        .kmap_atomic_pte = xen_kmap_atomic_pte,
1313#endif
1314
1315#ifdef CONFIG_X86_64
1316        .set_pte = xen_set_pte,
1317#else
1318        .set_pte = xen_set_pte_init,
1319#endif
1320        .set_pte_at = xen_set_pte_at,
1321        .set_pmd = xen_set_pmd_hyper,
1322
1323        .ptep_modify_prot_start = __ptep_modify_prot_start,
1324        .ptep_modify_prot_commit = __ptep_modify_prot_commit,
1325
1326        .pte_val = xen_pte_val,
1327        .pte_flags = native_pte_flags,
1328        .pgd_val = xen_pgd_val,
1329
1330        .make_pte = xen_make_pte,
1331        .make_pgd = xen_make_pgd,
1332
1333#ifdef CONFIG_X86_PAE
1334        .set_pte_atomic = xen_set_pte_atomic,
1335        .set_pte_present = xen_set_pte_at,
1336        .pte_clear = xen_pte_clear,
1337        .pmd_clear = xen_pmd_clear,
1338#endif  /* CONFIG_X86_PAE */
1339        .set_pud = xen_set_pud_hyper,
1340
1341        .make_pmd = xen_make_pmd,
1342        .pmd_val = xen_pmd_val,
1343
1344#if PAGETABLE_LEVELS == 4
1345        .pud_val = xen_pud_val,
1346        .make_pud = xen_make_pud,
1347        .set_pgd = xen_set_pgd_hyper,
1348
1349        .alloc_pud = xen_alloc_pte_init,
1350        .release_pud = xen_release_pte_init,
1351#endif  /* PAGETABLE_LEVELS == 4 */
1352
1353        .activate_mm = xen_activate_mm,
1354        .dup_mmap = xen_dup_mmap,
1355        .exit_mmap = xen_exit_mmap,
1356
1357        .lazy_mode = {
1358                .enter = paravirt_enter_lazy_mmu,
1359                .leave = xen_leave_lazy,
1360        },
1361
1362        .set_fixmap = xen_set_fixmap,
1363};
1364
1365static void xen_reboot(int reason)
1366{
1367        struct sched_shutdown r = { .reason = reason };
1368
1369#ifdef CONFIG_SMP
1370        smp_send_stop();
1371#endif
1372
1373        if (HYPERVISOR_sched_op(SCHEDOP_shutdown, &r))
1374                BUG();
1375}
1376
1377static void xen_restart(char *msg)
1378{
1379        xen_reboot(SHUTDOWN_reboot);
1380}
1381
1382static void xen_emergency_restart(void)
1383{
1384        xen_reboot(SHUTDOWN_reboot);
1385}
1386
1387static void xen_machine_halt(void)
1388{
1389        xen_reboot(SHUTDOWN_poweroff);
1390}
1391
1392static void xen_crash_shutdown(struct pt_regs *regs)
1393{
1394        xen_reboot(SHUTDOWN_crash);
1395}
1396
1397static const struct machine_ops __initdata xen_machine_ops = {
1398        .restart = xen_restart,
1399        .halt = xen_machine_halt,
1400        .power_off = xen_machine_halt,
1401        .shutdown = xen_machine_halt,
1402        .crash_shutdown = xen_crash_shutdown,
1403        .emergency_restart = xen_emergency_restart,
1404};
1405
1406
1407static void __init xen_reserve_top(void)
1408{
1409#ifdef CONFIG_X86_32
1410        unsigned long top = HYPERVISOR_VIRT_START;
1411        struct xen_platform_parameters pp;
1412
1413        if (HYPERVISOR_xen_version(XENVER_platform_parameters, &pp) == 0)
1414                top = pp.virt_start;
1415
1416        reserve_top_address(-top);
1417#endif  /* CONFIG_X86_32 */
1418}
1419
1420/*
1421 * Like __va(), but returns address in the kernel mapping (which is
1422 * all we have until the physical memory mapping has been set up.
1423 */
1424static void *__ka(phys_addr_t paddr)
1425{
1426#ifdef CONFIG_X86_64
1427        return (void *)(paddr + __START_KERNEL_map);
1428#else
1429        return __va(paddr);
1430#endif
1431}
1432
1433/* Convert a machine address to physical address */
1434static unsigned long m2p(phys_addr_t maddr)
1435{
1436        phys_addr_t paddr;
1437
1438        maddr &= PTE_PFN_MASK;
1439        paddr = mfn_to_pfn(maddr >> PAGE_SHIFT) << PAGE_SHIFT;
1440
1441        return paddr;
1442}
1443
1444/* Convert a machine address to kernel virtual */
1445static void *m2v(phys_addr_t maddr)
1446{
1447        return __ka(m2p(maddr));
1448}
1449
1450#ifdef CONFIG_X86_64
1451static void walk(pgd_t *pgd, unsigned long addr)
1452{
1453        unsigned l4idx = pgd_index(addr);
1454        unsigned l3idx = pud_index(addr);
1455        unsigned l2idx = pmd_index(addr);
1456        unsigned l1idx = pte_index(addr);
1457        pgd_t l4;
1458        pud_t l3;
1459        pmd_t l2;
1460        pte_t l1;
1461
1462        xen_raw_printk("walk %p, %lx -> %d %d %d %d\n",
1463                       pgd, addr, l4idx, l3idx, l2idx, l1idx);
1464
1465        l4 = pgd[l4idx];
1466        xen_raw_printk("  l4: %016lx\n", l4.pgd);
1467        xen_raw_printk("      %016lx\n", pgd_val(l4));
1468
1469        l3 = ((pud_t *)(m2v(l4.pgd)))[l3idx];
1470        xen_raw_printk("  l3: %016lx\n", l3.pud);
1471        xen_raw_printk("      %016lx\n", pud_val(l3));
1472
1473        l2 = ((pmd_t *)(m2v(l3.pud)))[l2idx];
1474        xen_raw_printk("  l2: %016lx\n", l2.pmd);
1475        xen_raw_printk("      %016lx\n", pmd_val(l2));
1476
1477        l1 = ((pte_t *)(m2v(l2.pmd)))[l1idx];
1478        xen_raw_printk("  l1: %016lx\n", l1.pte);
1479        xen_raw_printk("      %016lx\n", pte_val(l1));
1480}
1481#endif
1482
1483static void set_page_prot(void *addr, pgprot_t prot)
1484{
1485        unsigned long pfn = __pa(addr) >> PAGE_SHIFT;
1486        pte_t pte = pfn_pte(pfn, prot);
1487
1488        xen_raw_printk("addr=%p pfn=%lx mfn=%lx prot=%016llx pte=%016llx\n",
1489                       addr, pfn, get_phys_to_machine(pfn),
1490                       pgprot_val(prot), pte.pte);
1491
1492        if (HYPERVISOR_update_va_mapping((unsigned long)addr, pte, 0))
1493                BUG();
1494}
1495
1496static __init void xen_map_identity_early(pmd_t *pmd, unsigned long max_pfn)
1497{
1498        unsigned pmdidx, pteidx;
1499        unsigned ident_pte;
1500        unsigned long pfn;
1501
1502        ident_pte = 0;
1503        pfn = 0;
1504        for(pmdidx = 0; pmdidx < PTRS_PER_PMD && pfn < max_pfn; pmdidx++) {
1505                pte_t *pte_page;
1506
1507                /* Reuse or allocate a page of ptes */
1508                if (pmd_present(pmd[pmdidx]))
1509                        pte_page = m2v(pmd[pmdidx].pmd);
1510                else {
1511                        /* Check for free pte pages */
1512                        if (ident_pte == ARRAY_SIZE(level1_ident_pgt))
1513                                break;
1514
1515                        pte_page = &level1_ident_pgt[ident_pte];
1516                        ident_pte += PTRS_PER_PTE;
1517
1518                        pmd[pmdidx] = __pmd(__pa(pte_page) | _PAGE_TABLE);
1519                }
1520
1521                /* Install mappings */
1522                for(pteidx = 0; pteidx < PTRS_PER_PTE; pteidx++, pfn++) {
1523                        pte_t pte;
1524
1525                        if (pfn > max_pfn_mapped)
1526                                max_pfn_mapped = pfn;
1527
1528                        if (!pte_none(pte_page[pteidx]))
1529                                continue;
1530
1531                        pte = pfn_pte(pfn, PAGE_KERNEL_EXEC);
1532                        pte_page[pteidx] = pte;
1533                }
1534        }
1535
1536        for(pteidx = 0; pteidx < ident_pte; pteidx += PTRS_PER_PTE)
1537                set_page_prot(&level1_ident_pgt[pteidx], PAGE_KERNEL_RO);
1538
1539        set_page_prot(pmd, PAGE_KERNEL_RO);
1540}
1541
1542#ifdef CONFIG_X86_64
1543static void convert_pfn_mfn(void *v)
1544{
1545        pte_t *pte = v;
1546        int i;
1547
1548        /* All levels are converted the same way, so just treat them
1549           as ptes. */
1550        for(i = 0; i < PTRS_PER_PTE; i++)
1551                pte[i] = xen_make_pte(pte[i].pte);
1552}
1553
1554/*
1555 * Set up the inital kernel pagetable.
1556 *
1557 * We can construct this by grafting the Xen provided pagetable into
1558 * head_64.S's preconstructed pagetables.  We copy the Xen L2's into
1559 * level2_ident_pgt, level2_kernel_pgt and level2_fixmap_pgt.  This
1560 * means that only the kernel has a physical mapping to start with -
1561 * but that's enough to get __va working.  We need to fill in the rest
1562 * of the physical mapping once some sort of allocator has been set
1563 * up.
1564 */
1565static __init pgd_t *xen_setup_kernel_pagetable(pgd_t *pgd, unsigned long max_pfn)
1566{
1567        pud_t *l3;
1568        pmd_t *l2;
1569
1570        /* Zap identity mapping */
1571        init_level4_pgt[0] = __pgd(0);
1572
1573        /* Pre-constructed entries are in pfn, so convert to mfn */
1574        convert_pfn_mfn(init_level4_pgt);
1575        convert_pfn_mfn(level3_ident_pgt);
1576        convert_pfn_mfn(level3_kernel_pgt);
1577
1578        l3 = m2v(pgd[pgd_index(__START_KERNEL_map)].pgd);
1579        l2 = m2v(l3[pud_index(__START_KERNEL_map)].pud);
1580
1581        memcpy(level2_ident_pgt, l2, sizeof(pmd_t) * PTRS_PER_PMD);
1582        memcpy(level2_kernel_pgt, l2, sizeof(pmd_t) * PTRS_PER_PMD);
1583
1584        l3 = m2v(pgd[pgd_index(__START_KERNEL_map + PMD_SIZE)].pgd);
1585        l2 = m2v(l3[pud_index(__START_KERNEL_map + PMD_SIZE)].pud);
1586        memcpy(level2_fixmap_pgt, l2, sizeof(pmd_t) * PTRS_PER_PMD);
1587
1588        /* Set up identity map */
1589        xen_map_identity_early(level2_ident_pgt, max_pfn);
1590
1591        /* Make pagetable pieces RO */
1592        set_page_prot(init_level4_pgt, PAGE_KERNEL_RO);
1593        set_page_prot(level3_ident_pgt, PAGE_KERNEL_RO);
1594        set_page_prot(level3_kernel_pgt, PAGE_KERNEL_RO);
1595        set_page_prot(level3_user_vsyscall, PAGE_KERNEL_RO);
1596        set_page_prot(level2_kernel_pgt, PAGE_KERNEL_RO);
1597        set_page_prot(level2_fixmap_pgt, PAGE_KERNEL_RO);
1598
1599        /* Pin down new L4 */
1600        pin_pagetable_pfn(MMUEXT_PIN_L4_TABLE,
1601                          PFN_DOWN(__pa_symbol(init_level4_pgt)));
1602
1603        /* Unpin Xen-provided one */
1604        pin_pagetable_pfn(MMUEXT_UNPIN_TABLE, PFN_DOWN(__pa(pgd)));
1605
1606        /* Switch over */
1607        pgd = init_level4_pgt;
1608
1609        /*
1610         * At this stage there can be no user pgd, and no page
1611         * structure to attach it to, so make sure we just set kernel
1612         * pgd.
1613         */
1614        xen_mc_batch();
1615        __xen_write_cr3(true, __pa(pgd));
1616        xen_mc_issue(PARAVIRT_LAZY_CPU);
1617
1618        reserve_early(__pa(xen_start_info->pt_base),
1619                      __pa(xen_start_info->pt_base +
1620                           xen_start_info->nr_pt_frames * PAGE_SIZE),
1621                      "XEN PAGETABLES");
1622
1623        return pgd;
1624}
1625#else   /* !CONFIG_X86_64 */
1626static pmd_t level2_kernel_pgt[PTRS_PER_PMD] __page_aligned_bss;
1627
1628static __init pgd_t *xen_setup_kernel_pagetable(pgd_t *pgd, unsigned long max_pfn)
1629{
1630        pmd_t *kernel_pmd;
1631
1632        init_pg_tables_start = __pa(pgd);
1633        init_pg_tables_end = __pa(pgd) + xen_start_info->nr_pt_frames*PAGE_SIZE;
1634        max_pfn_mapped = PFN_DOWN(init_pg_tables_end + 512*1024);
1635
1636        kernel_pmd = m2v(pgd[KERNEL_PGD_BOUNDARY].pgd);
1637        memcpy(level2_kernel_pgt, kernel_pmd, sizeof(pmd_t) * PTRS_PER_PMD);
1638
1639        xen_map_identity_early(level2_kernel_pgt, max_pfn);
1640
1641        memcpy(swapper_pg_dir, pgd, sizeof(pgd_t) * PTRS_PER_PGD);
1642        set_pgd(&swapper_pg_dir[KERNEL_PGD_BOUNDARY],
1643                        __pgd(__pa(level2_kernel_pgt) | _PAGE_PRESENT));
1644
1645        set_page_prot(level2_kernel_pgt, PAGE_KERNEL_RO);
1646        set_page_prot(swapper_pg_dir, PAGE_KERNEL_RO);
1647        set_page_prot(empty_zero_page, PAGE_KERNEL_RO);
1648
1649        pin_pagetable_pfn(MMUEXT_UNPIN_TABLE, PFN_DOWN(__pa(pgd)));
1650
1651        xen_write_cr3(__pa(swapper_pg_dir));
1652
1653        pin_pagetable_pfn(MMUEXT_PIN_L3_TABLE, PFN_DOWN(__pa(swapper_pg_dir)));
1654
1655        return swapper_pg_dir;
1656}
1657#endif  /* CONFIG_X86_64 */
1658
1659/* First C function to be called on Xen boot */
1660asmlinkage void __init xen_start_kernel(void)
1661{
1662        pgd_t *pgd;
1663
1664        if (!xen_start_info)
1665                return;
1666
1667        BUG_ON(memcmp(xen_start_info->magic, "xen-3", 5) != 0);
1668
1669        xen_setup_features();
1670
1671        /* Install Xen paravirt ops */
1672        pv_info = xen_info;
1673        pv_init_ops = xen_init_ops;
1674        pv_time_ops = xen_time_ops;
1675        pv_cpu_ops = xen_cpu_ops;
1676        pv_irq_ops = xen_irq_ops;
1677        pv_apic_ops = xen_apic_ops;
1678        pv_mmu_ops = xen_mmu_ops;
1679
1680        if (xen_feature(XENFEAT_mmu_pt_update_preserve_ad)) {
1681                pv_mmu_ops.ptep_modify_prot_start = xen_ptep_modify_prot_start;
1682                pv_mmu_ops.ptep_modify_prot_commit = xen_ptep_modify_prot_commit;
1683        }
1684
1685        machine_ops = xen_machine_ops;
1686
1687#ifdef CONFIG_X86_64
1688        /* Disable until direct per-cpu data access. */
1689        have_vcpu_info_placement = 0;
1690        x86_64_init_pda();
1691#endif
1692
1693        xen_smp_init();
1694
1695        /* Get mfn list */
1696        if (!xen_feature(XENFEAT_auto_translated_physmap))
1697                xen_build_dynamic_phys_to_machine();
1698
1699        pgd = (pgd_t *)xen_start_info->pt_base;
1700
1701        /* Prevent unwanted bits from being set in PTEs. */
1702        __supported_pte_mask &= ~_PAGE_GLOBAL;
1703        if (!is_initial_xendomain())
1704                __supported_pte_mask &= ~(_PAGE_PWT | _PAGE_PCD);
1705
1706        /* Don't do the full vcpu_info placement stuff until we have a
1707           possible map and a non-dummy shared_info. */
1708        per_cpu(xen_vcpu, 0) = &HYPERVISOR_shared_info->vcpu_info[0];
1709
1710        local_irq_disable();
1711        early_boot_irqs_off();
1712
1713        xen_raw_console_write("mapping kernel into physical memory\n");
1714        pgd = xen_setup_kernel_pagetable(pgd, xen_start_info->nr_pages);
1715
1716        init_mm.pgd = pgd;
1717
1718        /* keep using Xen gdt for now; no urgent need to change it */
1719
1720        pv_info.kernel_rpl = 1;
1721        if (xen_feature(XENFEAT_supervisor_mode_kernel))
1722                pv_info.kernel_rpl = 0;
1723
1724        /* set the limit of our address space */
1725        xen_reserve_top();
1726
1727#ifdef CONFIG_X86_32
1728        /* set up basic CPUID stuff */
1729        cpu_detect(&new_cpu_data);
1730        new_cpu_data.hard_math = 1;
1731        new_cpu_data.x86_capability[0] = cpuid_edx(1);
1732#endif
1733
1734        /* Poke various useful things into boot_params */
1735        boot_params.hdr.type_of_loader = (9 << 4) | 0;
1736        boot_params.hdr.ramdisk_image = xen_start_info->mod_start
1737                ? __pa(xen_start_info->mod_start) : 0;
1738        boot_params.hdr.ramdisk_size = xen_start_info->mod_len;
1739        boot_params.hdr.cmd_line_ptr = __pa(xen_start_info->cmd_line);
1740
1741        if (!is_initial_xendomain()) {
1742                add_preferred_console("xenboot", 0, NULL);
1743                add_preferred_console("tty", 0, NULL);
1744                add_preferred_console("hvc", 0, NULL);
1745        }
1746
1747        xen_raw_console_write("about to get started...\n");
1748
1749#if 0
1750        xen_raw_printk("&boot_params=%p __pa(&boot_params)=%lx __va(__pa(&boot_params))=%lx\n",
1751                       &boot_params, __pa_symbol(&boot_params),
1752                       __va(__pa_symbol(&boot_params)));
1753
1754        walk(pgd, &boot_params);
1755        walk(pgd, __va(__pa(&boot_params)));
1756#endif
1757
1758        /* Start the world */
1759#ifdef CONFIG_X86_32
1760        i386_start_kernel();
1761#else
1762        x86_64_start_reservations((char *)__pa_symbol(&boot_params));
1763#endif
1764}
1765