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/features.h>
  34#include <xen/page.h>
  35#include <xen/hvc-console.h>
  36
  37#include <asm/paravirt.h>
  38#include <asm/apic.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
  60enum xen_domain_type xen_domain_type = XEN_NATIVE;
  61EXPORT_SYMBOL_GPL(xen_domain_type);
  62
  63/*
  64 * Identity map, in addition to plain kernel map.  This needs to be
  65 * large enough to allocate page table pages to allocate the rest.
  66 * Each page can map 2MB.
  67 */
  68static pte_t level1_ident_pgt[PTRS_PER_PTE * 4] __page_aligned_bss;
  69
  70#ifdef CONFIG_X86_64
  71/* l3 pud for userspace vsyscall mapping */
  72static pud_t level3_user_vsyscall[PTRS_PER_PUD] __page_aligned_bss;
  73#endif /* CONFIG_X86_64 */
  74
  75/*
  76 * Note about cr3 (pagetable base) values:
  77 *
  78 * xen_cr3 contains the current logical cr3 value; it contains the
  79 * last set cr3.  This may not be the current effective cr3, because
  80 * its update may be being lazily deferred.  However, a vcpu looking
  81 * at its own cr3 can use this value knowing that it everything will
  82 * be self-consistent.
  83 *
  84 * xen_current_cr3 contains the actual vcpu cr3; it is set once the
  85 * hypercall to set the vcpu cr3 is complete (so it may be a little
  86 * out of date, but it will never be set early).  If one vcpu is
  87 * looking at another vcpu's cr3 value, it should use this variable.
  88 */
  89DEFINE_PER_CPU(unsigned long, xen_cr3);  /* cr3 stored as physaddr */
  90DEFINE_PER_CPU(unsigned long, xen_current_cr3);  /* actual vcpu cr3 */
  91
  92struct start_info *xen_start_info;
  93EXPORT_SYMBOL_GPL(xen_start_info);
  94
  95struct shared_info xen_dummy_shared_info;
  96
  97/*
  98 * Point at some empty memory to start with. We map the real shared_info
  99 * page as soon as fixmap is up and running.
 100 */
 101struct shared_info *HYPERVISOR_shared_info = (void *)&xen_dummy_shared_info;
 102
 103/*
 104 * Flag to determine whether vcpu info placement is available on all
 105 * VCPUs.  We assume it is to start with, and then set it to zero on
 106 * the first failure.  This is because it can succeed on some VCPUs
 107 * and not others, since it can involve hypervisor memory allocation,
 108 * or because the guest failed to guarantee all the appropriate
 109 * constraints on all VCPUs (ie buffer can't cross a page boundary).
 110 *
 111 * Note that any particular CPU may be using a placed vcpu structure,
 112 * but we can only optimise if the all are.
 113 *
 114 * 0: not available, 1: available
 115 */
 116static int have_vcpu_info_placement =
 117#ifdef CONFIG_X86_32
 118        1
 119#else
 120        0
 121#endif
 122        ;
 123
 124
 125static void xen_vcpu_setup(int cpu)
 126{
 127        struct vcpu_register_vcpu_info info;
 128        int err;
 129        struct vcpu_info *vcpup;
 130
 131        BUG_ON(HYPERVISOR_shared_info == &xen_dummy_shared_info);
 132        per_cpu(xen_vcpu, cpu) = &HYPERVISOR_shared_info->vcpu_info[cpu];
 133
 134        if (!have_vcpu_info_placement)
 135                return;         /* already tested, not available */
 136
 137        vcpup = &per_cpu(xen_vcpu_info, cpu);
 138
 139        info.mfn = virt_to_mfn(vcpup);
 140        info.offset = offset_in_page(vcpup);
 141
 142        printk(KERN_DEBUG "trying to map vcpu_info %d at %p, mfn %llx, offset %d\n",
 143               cpu, vcpup, info.mfn, info.offset);
 144
 145        /* Check to see if the hypervisor will put the vcpu_info
 146           structure where we want it, which allows direct access via
 147           a percpu-variable. */
 148        err = HYPERVISOR_vcpu_op(VCPUOP_register_vcpu_info, cpu, &info);
 149
 150        if (err) {
 151                printk(KERN_DEBUG "register_vcpu_info failed: err=%d\n", err);
 152                have_vcpu_info_placement = 0;
 153        } else {
 154                /* This cpu is using the registered vcpu info, even if
 155                   later ones fail to. */
 156                per_cpu(xen_vcpu, cpu) = vcpup;
 157
 158                printk(KERN_DEBUG "cpu %d using vcpu_info at %p\n",
 159                       cpu, vcpup);
 160        }
 161}
 162
 163/*
 164 * On restore, set the vcpu placement up again.
 165 * If it fails, then we're in a bad state, since
 166 * we can't back out from using it...
 167 */
 168void xen_vcpu_restore(void)
 169{
 170        if (have_vcpu_info_placement) {
 171                int cpu;
 172
 173                for_each_online_cpu(cpu) {
 174                        bool other_cpu = (cpu != smp_processor_id());
 175
 176                        if (other_cpu &&
 177                            HYPERVISOR_vcpu_op(VCPUOP_down, cpu, NULL))
 178                                BUG();
 179
 180                        xen_vcpu_setup(cpu);
 181
 182                        if (other_cpu &&
 183                            HYPERVISOR_vcpu_op(VCPUOP_up, cpu, NULL))
 184                                BUG();
 185                }
 186
 187                BUG_ON(!have_vcpu_info_placement);
 188        }
 189}
 190
 191static void __init xen_banner(void)
 192{
 193        unsigned version = HYPERVISOR_xen_version(XENVER_version, NULL);
 194        struct xen_extraversion extra;
 195        HYPERVISOR_xen_version(XENVER_extraversion, &extra);
 196
 197        printk(KERN_INFO "Booting paravirtualized kernel on %s\n",
 198               pv_info.name);
 199        printk(KERN_INFO "Xen version: %d.%d%s%s\n",
 200               version >> 16, version & 0xffff, extra.extraversion,
 201               xen_feature(XENFEAT_mmu_pt_update_preserve_ad) ? " (preserve-AD)" : "");
 202}
 203
 204static void xen_cpuid(unsigned int *ax, unsigned int *bx,
 205                      unsigned int *cx, unsigned int *dx)
 206{
 207        unsigned maskedx = ~0;
 208
 209        /*
 210         * Mask out inconvenient features, to try and disable as many
 211         * unsupported kernel subsystems as possible.
 212         */
 213        if (*ax == 1)
 214                maskedx = ~((1 << X86_FEATURE_APIC) |  /* disable APIC */
 215                            (1 << X86_FEATURE_ACPI) |  /* disable ACPI */
 216                            (1 << X86_FEATURE_MCE)  |  /* disable MCE */
 217                            (1 << X86_FEATURE_MCA)  |  /* disable MCA */
 218                            (1 << X86_FEATURE_ACC));   /* thermal monitoring */
 219
 220        asm(XEN_EMULATE_PREFIX "cpuid"
 221                : "=a" (*ax),
 222                  "=b" (*bx),
 223                  "=c" (*cx),
 224                  "=d" (*dx)
 225                : "0" (*ax), "2" (*cx));
 226        *dx &= maskedx;
 227}
 228
 229static void xen_set_debugreg(int reg, unsigned long val)
 230{
 231        HYPERVISOR_set_debugreg(reg, val);
 232}
 233
 234static unsigned long xen_get_debugreg(int reg)
 235{
 236        return HYPERVISOR_get_debugreg(reg);
 237}
 238
 239static void xen_leave_lazy(void)
 240{
 241        paravirt_leave_lazy(paravirt_get_lazy_mode());
 242        xen_mc_flush();
 243}
 244
 245static unsigned long xen_store_tr(void)
 246{
 247        return 0;
 248}
 249
 250/*
 251 * Set the page permissions for a particular virtual address.  If the
 252 * address is a vmalloc mapping (or other non-linear mapping), then
 253 * find the linear mapping of the page and also set its protections to
 254 * match.
 255 */
 256static void set_aliased_prot(void *v, pgprot_t prot)
 257{
 258        int level;
 259        pte_t *ptep;
 260        pte_t pte;
 261        unsigned long pfn;
 262        struct page *page;
 263
 264        ptep = lookup_address((unsigned long)v, &level);
 265        BUG_ON(ptep == NULL);
 266
 267        pfn = pte_pfn(*ptep);
 268        page = pfn_to_page(pfn);
 269
 270        pte = pfn_pte(pfn, prot);
 271
 272        if (HYPERVISOR_update_va_mapping((unsigned long)v, pte, 0))
 273                BUG();
 274
 275        if (!PageHighMem(page)) {
 276                void *av = __va(PFN_PHYS(pfn));
 277
 278                if (av != v)
 279                        if (HYPERVISOR_update_va_mapping((unsigned long)av, pte, 0))
 280                                BUG();
 281        } else
 282                kmap_flush_unused();
 283}
 284
 285static void xen_alloc_ldt(struct desc_struct *ldt, unsigned entries)
 286{
 287        const unsigned entries_per_page = PAGE_SIZE / LDT_ENTRY_SIZE;
 288        int i;
 289
 290        for(i = 0; i < entries; i += entries_per_page)
 291                set_aliased_prot(ldt + i, PAGE_KERNEL_RO);
 292}
 293
 294static void xen_free_ldt(struct desc_struct *ldt, unsigned entries)
 295{
 296        const unsigned entries_per_page = PAGE_SIZE / LDT_ENTRY_SIZE;
 297        int i;
 298
 299        for(i = 0; i < entries; i += entries_per_page)
 300                set_aliased_prot(ldt + i, PAGE_KERNEL);
 301}
 302
 303static void xen_set_ldt(const void *addr, unsigned entries)
 304{
 305        struct mmuext_op *op;
 306        struct multicall_space mcs = xen_mc_entry(sizeof(*op));
 307
 308        op = mcs.args;
 309        op->cmd = MMUEXT_SET_LDT;
 310        op->arg1.linear_addr = (unsigned long)addr;
 311        op->arg2.nr_ents = entries;
 312
 313        MULTI_mmuext_op(mcs.mc, op, 1, NULL, DOMID_SELF);
 314
 315        xen_mc_issue(PARAVIRT_LAZY_CPU);
 316}
 317
 318static void xen_load_gdt(const struct desc_ptr *dtr)
 319{
 320        unsigned long *frames;
 321        unsigned long va = dtr->address;
 322        unsigned int size = dtr->size + 1;
 323        unsigned pages = (size + PAGE_SIZE - 1) / PAGE_SIZE;
 324        int f;
 325        struct multicall_space mcs;
 326
 327        /* A GDT can be up to 64k in size, which corresponds to 8192
 328           8-byte entries, or 16 4k pages.. */
 329
 330        BUG_ON(size > 65536);
 331        BUG_ON(va & ~PAGE_MASK);
 332
 333        mcs = xen_mc_entry(sizeof(*frames) * pages);
 334        frames = mcs.args;
 335
 336        for (f = 0; va < dtr->address + size; va += PAGE_SIZE, f++) {
 337                frames[f] = virt_to_mfn(va);
 338                make_lowmem_page_readonly((void *)va);
 339        }
 340
 341        MULTI_set_gdt(mcs.mc, frames, size / sizeof(struct desc_struct));
 342
 343        xen_mc_issue(PARAVIRT_LAZY_CPU);
 344}
 345
 346static void load_TLS_descriptor(struct thread_struct *t,
 347                                unsigned int cpu, unsigned int i)
 348{
 349        struct desc_struct *gdt = get_cpu_gdt_table(cpu);
 350        xmaddr_t maddr = virt_to_machine(&gdt[GDT_ENTRY_TLS_MIN+i]);
 351        struct multicall_space mc = __xen_mc_entry(0);
 352
 353        MULTI_update_descriptor(mc.mc, maddr.maddr, t->tls_array[i]);
 354}
 355
 356static void xen_load_tls(struct thread_struct *t, unsigned int cpu)
 357{
 358        /*
 359         * XXX sleazy hack: If we're being called in a lazy-cpu zone,
 360         * it means we're in a context switch, and %gs has just been
 361         * saved.  This means we can zero it out to prevent faults on
 362         * exit from the hypervisor if the next process has no %gs.
 363         * Either way, it has been saved, and the new value will get
 364         * loaded properly.  This will go away as soon as Xen has been
 365         * modified to not save/restore %gs for normal hypercalls.
 366         *
 367         * On x86_64, this hack is not used for %gs, because gs points
 368         * to KERNEL_GS_BASE (and uses it for PDA references), so we
 369         * must not zero %gs on x86_64
 370         *
 371         * For x86_64, we need to zero %fs, otherwise we may get an
 372         * exception between the new %fs descriptor being loaded and
 373         * %fs being effectively cleared at __switch_to().
 374         */
 375        if (paravirt_get_lazy_mode() == PARAVIRT_LAZY_CPU) {
 376#ifdef CONFIG_X86_32
 377                loadsegment(gs, 0);
 378#else
 379                loadsegment(fs, 0);
 380#endif
 381        }
 382
 383        xen_mc_batch();
 384
 385        load_TLS_descriptor(t, cpu, 0);
 386        load_TLS_descriptor(t, cpu, 1);
 387        load_TLS_descriptor(t, cpu, 2);
 388
 389        xen_mc_issue(PARAVIRT_LAZY_CPU);
 390}
 391
 392#ifdef CONFIG_X86_64
 393static void xen_load_gs_index(unsigned int idx)
 394{
 395        if (HYPERVISOR_set_segment_base(SEGBASE_GS_USER_SEL, idx))
 396                BUG();
 397}
 398#endif
 399
 400static void xen_write_ldt_entry(struct desc_struct *dt, int entrynum,
 401                                const void *ptr)
 402{
 403        xmaddr_t mach_lp = arbitrary_virt_to_machine(&dt[entrynum]);
 404        u64 entry = *(u64 *)ptr;
 405
 406        preempt_disable();
 407
 408        xen_mc_flush();
 409        if (HYPERVISOR_update_descriptor(mach_lp.maddr, entry))
 410                BUG();
 411
 412        preempt_enable();
 413}
 414
 415static int cvt_gate_to_trap(int vector, const gate_desc *val,
 416                            struct trap_info *info)
 417{
 418        if (val->type != 0xf && val->type != 0xe)
 419                return 0;
 420
 421        info->vector = vector;
 422        info->address = gate_offset(*val);
 423        info->cs = gate_segment(*val);
 424        info->flags = val->dpl;
 425        /* interrupt gates clear IF */
 426        if (val->type == 0xe)
 427                info->flags |= 4;
 428
 429        return 1;
 430}
 431
 432/* Locations of each CPU's IDT */
 433static DEFINE_PER_CPU(struct desc_ptr, idt_desc);
 434
 435/* Set an IDT entry.  If the entry is part of the current IDT, then
 436   also update Xen. */
 437static void xen_write_idt_entry(gate_desc *dt, int entrynum, const gate_desc *g)
 438{
 439        unsigned long p = (unsigned long)&dt[entrynum];
 440        unsigned long start, end;
 441
 442        preempt_disable();
 443
 444        start = __get_cpu_var(idt_desc).address;
 445        end = start + __get_cpu_var(idt_desc).size + 1;
 446
 447        xen_mc_flush();
 448
 449        native_write_idt_entry(dt, entrynum, g);
 450
 451        if (p >= start && (p + 8) <= end) {
 452                struct trap_info info[2];
 453
 454                info[1].address = 0;
 455
 456                if (cvt_gate_to_trap(entrynum, g, &info[0]))
 457                        if (HYPERVISOR_set_trap_table(info))
 458                                BUG();
 459        }
 460
 461        preempt_enable();
 462}
 463
 464static void xen_convert_trap_info(const struct desc_ptr *desc,
 465                                  struct trap_info *traps)
 466{
 467        unsigned in, out, count;
 468
 469        count = (desc->size+1) / sizeof(gate_desc);
 470        BUG_ON(count > 256);
 471
 472        for (in = out = 0; in < count; in++) {
 473                gate_desc *entry = (gate_desc*)(desc->address) + in;
 474
 475                if (cvt_gate_to_trap(in, entry, &traps[out]))
 476                        out++;
 477        }
 478        traps[out].address = 0;
 479}
 480
 481void xen_copy_trap_info(struct trap_info *traps)
 482{
 483        const struct desc_ptr *desc = &__get_cpu_var(idt_desc);
 484
 485        xen_convert_trap_info(desc, traps);
 486}
 487
 488/* Load a new IDT into Xen.  In principle this can be per-CPU, so we
 489   hold a spinlock to protect the static traps[] array (static because
 490   it avoids allocation, and saves stack space). */
 491static void xen_load_idt(const struct desc_ptr *desc)
 492{
 493        static DEFINE_SPINLOCK(lock);
 494        static struct trap_info traps[257];
 495
 496        spin_lock(&lock);
 497
 498        __get_cpu_var(idt_desc) = *desc;
 499
 500        xen_convert_trap_info(desc, traps);
 501
 502        xen_mc_flush();
 503        if (HYPERVISOR_set_trap_table(traps))
 504                BUG();
 505
 506        spin_unlock(&lock);
 507}
 508
 509/* Write a GDT descriptor entry.  Ignore LDT descriptors, since
 510   they're handled differently. */
 511static void xen_write_gdt_entry(struct desc_struct *dt, int entry,
 512                                const void *desc, int type)
 513{
 514        preempt_disable();
 515
 516        switch (type) {
 517        case DESC_LDT:
 518        case DESC_TSS:
 519                /* ignore */
 520                break;
 521
 522        default: {
 523                xmaddr_t maddr = virt_to_machine(&dt[entry]);
 524
 525                xen_mc_flush();
 526                if (HYPERVISOR_update_descriptor(maddr.maddr, *(u64 *)desc))
 527                        BUG();
 528        }
 529
 530        }
 531
 532        preempt_enable();
 533}
 534
 535static void xen_load_sp0(struct tss_struct *tss,
 536                         struct thread_struct *thread)
 537{
 538        struct multicall_space mcs = xen_mc_entry(0);
 539        MULTI_stack_switch(mcs.mc, __KERNEL_DS, thread->sp0);
 540        xen_mc_issue(PARAVIRT_LAZY_CPU);
 541}
 542
 543static void xen_set_iopl_mask(unsigned mask)
 544{
 545        struct physdev_set_iopl set_iopl;
 546
 547        /* Force the change at ring 0. */
 548        set_iopl.iopl = (mask == 0) ? 1 : (mask >> 12) & 3;
 549        HYPERVISOR_physdev_op(PHYSDEVOP_set_iopl, &set_iopl);
 550}
 551
 552static void xen_io_delay(void)
 553{
 554}
 555
 556#ifdef CONFIG_X86_LOCAL_APIC
 557static u32 xen_apic_read(u32 reg)
 558{
 559        return 0;
 560}
 561
 562static void xen_apic_write(u32 reg, u32 val)
 563{
 564        /* Warn to see if there's any stray references */
 565        WARN_ON(1);
 566}
 567
 568static u64 xen_apic_icr_read(void)
 569{
 570        return 0;
 571}
 572
 573static void xen_apic_icr_write(u32 low, u32 id)
 574{
 575        /* Warn to see if there's any stray references */
 576        WARN_ON(1);
 577}
 578
 579static void xen_apic_wait_icr_idle(void)
 580{
 581        return;
 582}
 583
 584static u32 xen_safe_apic_wait_icr_idle(void)
 585{
 586        return 0;
 587}
 588
 589static struct apic_ops xen_basic_apic_ops = {
 590        .read = xen_apic_read,
 591        .write = xen_apic_write,
 592        .icr_read = xen_apic_icr_read,
 593        .icr_write = xen_apic_icr_write,
 594        .wait_icr_idle = xen_apic_wait_icr_idle,
 595        .safe_wait_icr_idle = xen_safe_apic_wait_icr_idle,
 596};
 597
 598#endif
 599
 600static void xen_flush_tlb(void)
 601{
 602        struct mmuext_op *op;
 603        struct multicall_space mcs;
 604
 605        preempt_disable();
 606
 607        mcs = xen_mc_entry(sizeof(*op));
 608
 609        op = mcs.args;
 610        op->cmd = MMUEXT_TLB_FLUSH_LOCAL;
 611        MULTI_mmuext_op(mcs.mc, op, 1, NULL, DOMID_SELF);
 612
 613        xen_mc_issue(PARAVIRT_LAZY_MMU);
 614
 615        preempt_enable();
 616}
 617
 618static void xen_flush_tlb_single(unsigned long addr)
 619{
 620        struct mmuext_op *op;
 621        struct multicall_space mcs;
 622
 623        preempt_disable();
 624
 625        mcs = xen_mc_entry(sizeof(*op));
 626        op = mcs.args;
 627        op->cmd = MMUEXT_INVLPG_LOCAL;
 628        op->arg1.linear_addr = addr & PAGE_MASK;
 629        MULTI_mmuext_op(mcs.mc, op, 1, NULL, DOMID_SELF);
 630
 631        xen_mc_issue(PARAVIRT_LAZY_MMU);
 632
 633        preempt_enable();
 634}
 635
 636static void xen_flush_tlb_others(const cpumask_t *cpus, struct mm_struct *mm,
 637                                 unsigned long va)
 638{
 639        struct {
 640                struct mmuext_op op;
 641                cpumask_t mask;
 642        } *args;
 643        cpumask_t cpumask = *cpus;
 644        struct multicall_space mcs;
 645
 646        /*
 647         * A couple of (to be removed) sanity checks:
 648         *
 649         * - current CPU must not be in mask
 650         * - mask must exist :)
 651         */
 652        BUG_ON(cpus_empty(cpumask));
 653        BUG_ON(cpu_isset(smp_processor_id(), cpumask));
 654        BUG_ON(!mm);
 655
 656        /* If a CPU which we ran on has gone down, OK. */
 657        cpus_and(cpumask, cpumask, cpu_online_map);
 658        if (cpus_empty(cpumask))
 659                return;
 660
 661        mcs = xen_mc_entry(sizeof(*args));
 662        args = mcs.args;
 663        args->mask = cpumask;
 664        args->op.arg2.vcpumask = &args->mask;
 665
 666        if (va == TLB_FLUSH_ALL) {
 667                args->op.cmd = MMUEXT_TLB_FLUSH_MULTI;
 668        } else {
 669                args->op.cmd = MMUEXT_INVLPG_MULTI;
 670                args->op.arg1.linear_addr = va;
 671        }
 672
 673        MULTI_mmuext_op(mcs.mc, &args->op, 1, NULL, DOMID_SELF);
 674
 675        xen_mc_issue(PARAVIRT_LAZY_MMU);
 676}
 677
 678static void xen_clts(void)
 679{
 680        struct multicall_space mcs;
 681
 682        mcs = xen_mc_entry(0);
 683
 684        MULTI_fpu_taskswitch(mcs.mc, 0);
 685
 686        xen_mc_issue(PARAVIRT_LAZY_CPU);
 687}
 688
 689static void xen_write_cr0(unsigned long cr0)
 690{
 691        struct multicall_space mcs;
 692
 693        /* Only pay attention to cr0.TS; everything else is
 694           ignored. */
 695        mcs = xen_mc_entry(0);
 696
 697        MULTI_fpu_taskswitch(mcs.mc, (cr0 & X86_CR0_TS) != 0);
 698
 699        xen_mc_issue(PARAVIRT_LAZY_CPU);
 700}
 701
 702static void xen_write_cr2(unsigned long cr2)
 703{
 704        x86_read_percpu(xen_vcpu)->arch.cr2 = cr2;
 705}
 706
 707static unsigned long xen_read_cr2(void)
 708{
 709        return x86_read_percpu(xen_vcpu)->arch.cr2;
 710}
 711
 712static unsigned long xen_read_cr2_direct(void)
 713{
 714        return x86_read_percpu(xen_vcpu_info.arch.cr2);
 715}
 716
 717static void xen_write_cr4(unsigned long cr4)
 718{
 719        cr4 &= ~X86_CR4_PGE;
 720        cr4 &= ~X86_CR4_PSE;
 721
 722        native_write_cr4(cr4);
 723}
 724
 725static unsigned long xen_read_cr3(void)
 726{
 727        return x86_read_percpu(xen_cr3);
 728}
 729
 730static void set_current_cr3(void *v)
 731{
 732        x86_write_percpu(xen_current_cr3, (unsigned long)v);
 733}
 734
 735static void __xen_write_cr3(bool kernel, unsigned long cr3)
 736{
 737        struct mmuext_op *op;
 738        struct multicall_space mcs;
 739        unsigned long mfn;
 740
 741        if (cr3)
 742                mfn = pfn_to_mfn(PFN_DOWN(cr3));
 743        else
 744                mfn = 0;
 745
 746        WARN_ON(mfn == 0 && kernel);
 747
 748        mcs = __xen_mc_entry(sizeof(*op));
 749
 750        op = mcs.args;
 751        op->cmd = kernel ? MMUEXT_NEW_BASEPTR : MMUEXT_NEW_USER_BASEPTR;
 752        op->arg1.mfn = mfn;
 753
 754        MULTI_mmuext_op(mcs.mc, op, 1, NULL, DOMID_SELF);
 755
 756        if (kernel) {
 757                x86_write_percpu(xen_cr3, cr3);
 758
 759                /* Update xen_current_cr3 once the batch has actually
 760                   been submitted. */
 761                xen_mc_callback(set_current_cr3, (void *)cr3);
 762        }
 763}
 764
 765static void xen_write_cr3(unsigned long cr3)
 766{
 767        BUG_ON(preemptible());
 768
 769        xen_mc_batch();  /* disables interrupts */
 770
 771        /* Update while interrupts are disabled, so its atomic with
 772           respect to ipis */
 773        x86_write_percpu(xen_cr3, cr3);
 774
 775        __xen_write_cr3(true, cr3);
 776
 777#ifdef CONFIG_X86_64
 778        {
 779                pgd_t *user_pgd = xen_get_user_pgd(__va(cr3));
 780                if (user_pgd)
 781                        __xen_write_cr3(false, __pa(user_pgd));
 782                else
 783                        __xen_write_cr3(false, 0);
 784        }
 785#endif
 786
 787        xen_mc_issue(PARAVIRT_LAZY_CPU);  /* interrupts restored */
 788}
 789
 790static int xen_write_msr_safe(unsigned int msr, unsigned low, unsigned high)
 791{
 792        int ret;
 793
 794        ret = 0;
 795
 796        switch(msr) {
 797#ifdef CONFIG_X86_64
 798                unsigned which;
 799                u64 base;
 800
 801        case MSR_FS_BASE:               which = SEGBASE_FS; goto set;
 802        case MSR_KERNEL_GS_BASE:        which = SEGBASE_GS_USER; goto set;
 803        case MSR_GS_BASE:               which = SEGBASE_GS_KERNEL; goto set;
 804
 805        set:
 806                base = ((u64)high << 32) | low;
 807                if (HYPERVISOR_set_segment_base(which, base) != 0)
 808                        ret = -EFAULT;
 809                break;
 810#endif
 811
 812        case MSR_STAR:
 813        case MSR_CSTAR:
 814        case MSR_LSTAR:
 815        case MSR_SYSCALL_MASK:
 816        case MSR_IA32_SYSENTER_CS:
 817        case MSR_IA32_SYSENTER_ESP:
 818        case MSR_IA32_SYSENTER_EIP:
 819                /* Fast syscall setup is all done in hypercalls, so
 820                   these are all ignored.  Stub them out here to stop
 821                   Xen console noise. */
 822                break;
 823
 824        default:
 825                ret = native_write_msr_safe(msr, low, high);
 826        }
 827
 828        return ret;
 829}
 830
 831/* Early in boot, while setting up the initial pagetable, assume
 832   everything is pinned. */
 833static __init void xen_alloc_pte_init(struct mm_struct *mm, unsigned long pfn)
 834{
 835#ifdef CONFIG_FLATMEM
 836        BUG_ON(mem_map);        /* should only be used early */
 837#endif
 838        make_lowmem_page_readonly(__va(PFN_PHYS(pfn)));
 839}
 840
 841/* Early release_pte assumes that all pts are pinned, since there's
 842   only init_mm and anything attached to that is pinned. */
 843static void xen_release_pte_init(unsigned long pfn)
 844{
 845        make_lowmem_page_readwrite(__va(PFN_PHYS(pfn)));
 846}
 847
 848static void pin_pagetable_pfn(unsigned cmd, unsigned long pfn)
 849{
 850        struct mmuext_op op;
 851        op.cmd = cmd;
 852        op.arg1.mfn = pfn_to_mfn(pfn);
 853        if (HYPERVISOR_mmuext_op(&op, 1, NULL, DOMID_SELF))
 854                BUG();
 855}
 856
 857/* This needs to make sure the new pte page is pinned iff its being
 858   attached to a pinned pagetable. */
 859static void xen_alloc_ptpage(struct mm_struct *mm, unsigned long pfn, unsigned level)
 860{
 861        struct page *page = pfn_to_page(pfn);
 862
 863        if (PagePinned(virt_to_page(mm->pgd))) {
 864                SetPagePinned(page);
 865
 866                vm_unmap_aliases();
 867                if (!PageHighMem(page)) {
 868                        make_lowmem_page_readonly(__va(PFN_PHYS((unsigned long)pfn)));
 869                        if (level == PT_PTE && USE_SPLIT_PTLOCKS)
 870                                pin_pagetable_pfn(MMUEXT_PIN_L1_TABLE, pfn);
 871                } else {
 872                        /* make sure there are no stray mappings of
 873                           this page */
 874                        kmap_flush_unused();
 875                }
 876        }
 877}
 878
 879static void xen_alloc_pte(struct mm_struct *mm, unsigned long pfn)
 880{
 881        xen_alloc_ptpage(mm, pfn, PT_PTE);
 882}
 883
 884static void xen_alloc_pmd(struct mm_struct *mm, unsigned long pfn)
 885{
 886        xen_alloc_ptpage(mm, pfn, PT_PMD);
 887}
 888
 889static int xen_pgd_alloc(struct mm_struct *mm)
 890{
 891        pgd_t *pgd = mm->pgd;
 892        int ret = 0;
 893
 894        BUG_ON(PagePinned(virt_to_page(pgd)));
 895
 896#ifdef CONFIG_X86_64
 897        {
 898                struct page *page = virt_to_page(pgd);
 899                pgd_t *user_pgd;
 900
 901                BUG_ON(page->private != 0);
 902
 903                ret = -ENOMEM;
 904
 905                user_pgd = (pgd_t *)__get_free_page(GFP_KERNEL | __GFP_ZERO);
 906                page->private = (unsigned long)user_pgd;
 907
 908                if (user_pgd != NULL) {
 909                        user_pgd[pgd_index(VSYSCALL_START)] =
 910                                __pgd(__pa(level3_user_vsyscall) | _PAGE_TABLE);
 911                        ret = 0;
 912                }
 913
 914                BUG_ON(PagePinned(virt_to_page(xen_get_user_pgd(pgd))));
 915        }
 916#endif
 917
 918        return ret;
 919}
 920
 921static void xen_pgd_free(struct mm_struct *mm, pgd_t *pgd)
 922{
 923#ifdef CONFIG_X86_64
 924        pgd_t *user_pgd = xen_get_user_pgd(pgd);
 925
 926        if (user_pgd)
 927                free_page((unsigned long)user_pgd);
 928#endif
 929}
 930
 931/* This should never happen until we're OK to use struct page */
 932static void xen_release_ptpage(unsigned long pfn, unsigned level)
 933{
 934        struct page *page = pfn_to_page(pfn);
 935
 936        if (PagePinned(page)) {
 937                if (!PageHighMem(page)) {
 938                        if (level == PT_PTE && USE_SPLIT_PTLOCKS)
 939                                pin_pagetable_pfn(MMUEXT_UNPIN_TABLE, pfn);
 940                        make_lowmem_page_readwrite(__va(PFN_PHYS(pfn)));
 941                }
 942                ClearPagePinned(page);
 943        }
 944}
 945
 946static void xen_release_pte(unsigned long pfn)
 947{
 948        xen_release_ptpage(pfn, PT_PTE);
 949}
 950
 951static void xen_release_pmd(unsigned long pfn)
 952{
 953        xen_release_ptpage(pfn, PT_PMD);
 954}
 955
 956#if PAGETABLE_LEVELS == 4
 957static void xen_alloc_pud(struct mm_struct *mm, unsigned long pfn)
 958{
 959        xen_alloc_ptpage(mm, pfn, PT_PUD);
 960}
 961
 962static void xen_release_pud(unsigned long pfn)
 963{
 964        xen_release_ptpage(pfn, PT_PUD);
 965}
 966#endif
 967
 968#ifdef CONFIG_HIGHPTE
 969static void *xen_kmap_atomic_pte(struct page *page, enum km_type type)
 970{
 971        pgprot_t prot = PAGE_KERNEL;
 972
 973        if (PagePinned(page))
 974                prot = PAGE_KERNEL_RO;
 975
 976        if (0 && PageHighMem(page))
 977                printk("mapping highpte %lx type %d prot %s\n",
 978                       page_to_pfn(page), type,
 979                       (unsigned long)pgprot_val(prot) & _PAGE_RW ? "WRITE" : "READ");
 980
 981        return kmap_atomic_prot(page, type, prot);
 982}
 983#endif
 984
 985#ifdef CONFIG_X86_32
 986static __init pte_t mask_rw_pte(pte_t *ptep, pte_t pte)
 987{
 988        /* If there's an existing pte, then don't allow _PAGE_RW to be set */
 989        if (pte_val_ma(*ptep) & _PAGE_PRESENT)
 990                pte = __pte_ma(((pte_val_ma(*ptep) & _PAGE_RW) | ~_PAGE_RW) &
 991                               pte_val_ma(pte));
 992
 993        return pte;
 994}
 995
 996/* Init-time set_pte while constructing initial pagetables, which
 997   doesn't allow RO pagetable pages to be remapped RW */
 998static __init void xen_set_pte_init(pte_t *ptep, pte_t pte)
 999{
1000        pte = mask_rw_pte(ptep, pte);
1001
1002        xen_set_pte(ptep, pte);
1003}
1004#endif
1005
1006static __init void xen_pagetable_setup_start(pgd_t *base)
1007{
1008}
1009
1010void xen_setup_shared_info(void)
1011{
1012        if (!xen_feature(XENFEAT_auto_translated_physmap)) {
1013                set_fixmap(FIX_PARAVIRT_BOOTMAP,
1014                           xen_start_info->shared_info);
1015
1016                HYPERVISOR_shared_info =
1017                        (struct shared_info *)fix_to_virt(FIX_PARAVIRT_BOOTMAP);
1018        } else
1019                HYPERVISOR_shared_info =
1020                        (struct shared_info *)__va(xen_start_info->shared_info);
1021
1022#ifndef CONFIG_SMP
1023        /* In UP this is as good a place as any to set up shared info */
1024        xen_setup_vcpu_info_placement();
1025#endif
1026
1027        xen_setup_mfn_list_list();
1028}
1029
1030static __init void xen_pagetable_setup_done(pgd_t *base)
1031{
1032        xen_setup_shared_info();
1033}
1034
1035static __init void xen_post_allocator_init(void)
1036{
1037        pv_mmu_ops.set_pte = xen_set_pte;
1038        pv_mmu_ops.set_pmd = xen_set_pmd;
1039        pv_mmu_ops.set_pud = xen_set_pud;
1040#if PAGETABLE_LEVELS == 4
1041        pv_mmu_ops.set_pgd = xen_set_pgd;
1042#endif
1043
1044        /* This will work as long as patching hasn't happened yet
1045           (which it hasn't) */
1046        pv_mmu_ops.alloc_pte = xen_alloc_pte;
1047        pv_mmu_ops.alloc_pmd = xen_alloc_pmd;
1048        pv_mmu_ops.release_pte = xen_release_pte;
1049        pv_mmu_ops.release_pmd = xen_release_pmd;
1050#if PAGETABLE_LEVELS == 4
1051        pv_mmu_ops.alloc_pud = xen_alloc_pud;
1052        pv_mmu_ops.release_pud = xen_release_pud;
1053#endif
1054
1055#ifdef CONFIG_X86_64
1056        SetPagePinned(virt_to_page(level3_user_vsyscall));
1057#endif
1058        xen_mark_init_mm_pinned();
1059}
1060
1061/* This is called once we have the cpu_possible_map */
1062void xen_setup_vcpu_info_placement(void)
1063{
1064        int cpu;
1065
1066        for_each_possible_cpu(cpu)
1067                xen_vcpu_setup(cpu);
1068
1069        /* xen_vcpu_setup managed to place the vcpu_info within the
1070           percpu area for all cpus, so make use of it */
1071        if (have_vcpu_info_placement) {
1072                printk(KERN_INFO "Xen: using vcpu_info placement\n");
1073
1074                pv_irq_ops.save_fl = xen_save_fl_direct;
1075                pv_irq_ops.restore_fl = xen_restore_fl_direct;
1076                pv_irq_ops.irq_disable = xen_irq_disable_direct;
1077                pv_irq_ops.irq_enable = xen_irq_enable_direct;
1078                pv_mmu_ops.read_cr2 = xen_read_cr2_direct;
1079        }
1080}
1081
1082static unsigned xen_patch(u8 type, u16 clobbers, void *insnbuf,
1083                          unsigned long addr, unsigned len)
1084{
1085        char *start, *end, *reloc;
1086        unsigned ret;
1087
1088        start = end = reloc = NULL;
1089
1090#define SITE(op, x)                                                     \
1091        case PARAVIRT_PATCH(op.x):                                      \
1092        if (have_vcpu_info_placement) {                                 \
1093                start = (char *)xen_##x##_direct;                       \
1094                end = xen_##x##_direct_end;                             \
1095                reloc = xen_##x##_direct_reloc;                         \
1096        }                                                               \
1097        goto patch_site
1098
1099        switch (type) {
1100                SITE(pv_irq_ops, irq_enable);
1101                SITE(pv_irq_ops, irq_disable);
1102                SITE(pv_irq_ops, save_fl);
1103                SITE(pv_irq_ops, restore_fl);
1104#undef SITE
1105
1106        patch_site:
1107                if (start == NULL || (end-start) > len)
1108                        goto default_patch;
1109
1110                ret = paravirt_patch_insns(insnbuf, len, start, end);
1111
1112                /* Note: because reloc is assigned from something that
1113                   appears to be an array, gcc assumes it's non-null,
1114                   but doesn't know its relationship with start and
1115                   end. */
1116                if (reloc > start && reloc < end) {
1117                        int reloc_off = reloc - start;
1118                        long *relocp = (long *)(insnbuf + reloc_off);
1119                        long delta = start - (char *)addr;
1120
1121                        *relocp += delta;
1122                }
1123                break;
1124
1125        default_patch:
1126        default:
1127                ret = paravirt_patch_default(type, clobbers, insnbuf,
1128                                             addr, len);
1129                break;
1130        }
1131
1132        return ret;
1133}
1134
1135static void xen_set_fixmap(unsigned idx, unsigned long phys, pgprot_t prot)
1136{
1137        pte_t pte;
1138
1139        phys >>= PAGE_SHIFT;
1140
1141        switch (idx) {
1142        case FIX_BTMAP_END ... FIX_BTMAP_BEGIN:
1143#ifdef CONFIG_X86_F00F_BUG
1144        case FIX_F00F_IDT:
1145#endif
1146#ifdef CONFIG_X86_32
1147        case FIX_WP_TEST:
1148        case FIX_VDSO:
1149# ifdef CONFIG_HIGHMEM
1150        case FIX_KMAP_BEGIN ... FIX_KMAP_END:
1151# endif
1152#else
1153        case VSYSCALL_LAST_PAGE ... VSYSCALL_FIRST_PAGE:
1154#endif
1155#ifdef CONFIG_X86_LOCAL_APIC
1156        case FIX_APIC_BASE:     /* maps dummy local APIC */
1157#endif
1158                pte = pfn_pte(phys, prot);
1159                break;
1160
1161        default:
1162                pte = mfn_pte(phys, prot);
1163                break;
1164        }
1165
1166        __native_set_fixmap(idx, pte);
1167
1168#ifdef CONFIG_X86_64
1169        /* Replicate changes to map the vsyscall page into the user
1170           pagetable vsyscall mapping. */
1171        if (idx >= VSYSCALL_LAST_PAGE && idx <= VSYSCALL_FIRST_PAGE) {
1172                unsigned long vaddr = __fix_to_virt(idx);
1173                set_pte_vaddr_pud(level3_user_vsyscall, vaddr, pte);
1174        }
1175#endif
1176}
1177
1178static const struct pv_info xen_info __initdata = {
1179        .paravirt_enabled = 1,
1180        .shared_kernel_pmd = 0,
1181
1182        .name = "Xen",
1183};
1184
1185static const struct pv_init_ops xen_init_ops __initdata = {
1186        .patch = xen_patch,
1187
1188        .banner = xen_banner,
1189        .memory_setup = xen_memory_setup,
1190        .arch_setup = xen_arch_setup,
1191        .post_allocator_init = xen_post_allocator_init,
1192};
1193
1194static const struct pv_time_ops xen_time_ops __initdata = {
1195        .time_init = xen_time_init,
1196
1197        .set_wallclock = xen_set_wallclock,
1198        .get_wallclock = xen_get_wallclock,
1199        .get_tsc_khz = xen_tsc_khz,
1200        .sched_clock = xen_sched_clock,
1201};
1202
1203static const struct pv_cpu_ops xen_cpu_ops __initdata = {
1204        .cpuid = xen_cpuid,
1205
1206        .set_debugreg = xen_set_debugreg,
1207        .get_debugreg = xen_get_debugreg,
1208
1209        .clts = xen_clts,
1210
1211        .read_cr0 = native_read_cr0,
1212        .write_cr0 = xen_write_cr0,
1213
1214        .read_cr4 = native_read_cr4,
1215        .read_cr4_safe = native_read_cr4_safe,
1216        .write_cr4 = xen_write_cr4,
1217
1218        .wbinvd = native_wbinvd,
1219
1220        .read_msr = native_read_msr_safe,
1221        .write_msr = xen_write_msr_safe,
1222        .read_tsc = native_read_tsc,
1223        .read_pmc = native_read_pmc,
1224
1225        .iret = xen_iret,
1226        .irq_enable_sysexit = xen_sysexit,
1227#ifdef CONFIG_X86_64
1228        .usergs_sysret32 = xen_sysret32,
1229        .usergs_sysret64 = xen_sysret64,
1230#endif
1231
1232        .load_tr_desc = paravirt_nop,
1233        .set_ldt = xen_set_ldt,
1234        .load_gdt = xen_load_gdt,
1235        .load_idt = xen_load_idt,
1236        .load_tls = xen_load_tls,
1237#ifdef CONFIG_X86_64
1238        .load_gs_index = xen_load_gs_index,
1239#endif
1240
1241        .alloc_ldt = xen_alloc_ldt,
1242        .free_ldt = xen_free_ldt,
1243
1244        .store_gdt = native_store_gdt,
1245        .store_idt = native_store_idt,
1246        .store_tr = xen_store_tr,
1247
1248        .write_ldt_entry = xen_write_ldt_entry,
1249        .write_gdt_entry = xen_write_gdt_entry,
1250        .write_idt_entry = xen_write_idt_entry,
1251        .load_sp0 = xen_load_sp0,
1252
1253        .set_iopl_mask = xen_set_iopl_mask,
1254        .io_delay = xen_io_delay,
1255
1256        /* Xen takes care of %gs when switching to usermode for us */
1257        .swapgs = paravirt_nop,
1258
1259        .lazy_mode = {
1260                .enter = paravirt_enter_lazy_cpu,
1261                .leave = xen_leave_lazy,
1262        },
1263};
1264
1265static const struct pv_apic_ops xen_apic_ops __initdata = {
1266#ifdef CONFIG_X86_LOCAL_APIC
1267        .setup_boot_clock = paravirt_nop,
1268        .setup_secondary_clock = paravirt_nop,
1269        .startup_ipi_hook = paravirt_nop,
1270#endif
1271};
1272
1273static const struct pv_mmu_ops xen_mmu_ops __initdata = {
1274        .pagetable_setup_start = xen_pagetable_setup_start,
1275        .pagetable_setup_done = xen_pagetable_setup_done,
1276
1277        .read_cr2 = xen_read_cr2,
1278        .write_cr2 = xen_write_cr2,
1279
1280        .read_cr3 = xen_read_cr3,
1281        .write_cr3 = xen_write_cr3,
1282
1283        .flush_tlb_user = xen_flush_tlb,
1284        .flush_tlb_kernel = xen_flush_tlb,
1285        .flush_tlb_single = xen_flush_tlb_single,
1286        .flush_tlb_others = xen_flush_tlb_others,
1287
1288        .pte_update = paravirt_nop,
1289        .pte_update_defer = paravirt_nop,
1290
1291        .pgd_alloc = xen_pgd_alloc,
1292        .pgd_free = xen_pgd_free,
1293
1294        .alloc_pte = xen_alloc_pte_init,
1295        .release_pte = xen_release_pte_init,
1296        .alloc_pmd = xen_alloc_pte_init,
1297        .alloc_pmd_clone = paravirt_nop,
1298        .release_pmd = xen_release_pte_init,
1299
1300#ifdef CONFIG_HIGHPTE
1301        .kmap_atomic_pte = xen_kmap_atomic_pte,
1302#endif
1303
1304#ifdef CONFIG_X86_64
1305        .set_pte = xen_set_pte,
1306#else
1307        .set_pte = xen_set_pte_init,
1308#endif
1309        .set_pte_at = xen_set_pte_at,
1310        .set_pmd = xen_set_pmd_hyper,
1311
1312        .ptep_modify_prot_start = __ptep_modify_prot_start,
1313        .ptep_modify_prot_commit = __ptep_modify_prot_commit,
1314
1315        .pte_val = xen_pte_val,
1316        .pte_flags = native_pte_flags,
1317        .pgd_val = xen_pgd_val,
1318
1319        .make_pte = xen_make_pte,
1320        .make_pgd = xen_make_pgd,
1321
1322#ifdef CONFIG_X86_PAE
1323        .set_pte_atomic = xen_set_pte_atomic,
1324        .set_pte_present = xen_set_pte_at,
1325        .pte_clear = xen_pte_clear,
1326        .pmd_clear = xen_pmd_clear,
1327#endif  /* CONFIG_X86_PAE */
1328        .set_pud = xen_set_pud_hyper,
1329
1330        .make_pmd = xen_make_pmd,
1331        .pmd_val = xen_pmd_val,
1332
1333#if PAGETABLE_LEVELS == 4
1334        .pud_val = xen_pud_val,
1335        .make_pud = xen_make_pud,
1336        .set_pgd = xen_set_pgd_hyper,
1337
1338        .alloc_pud = xen_alloc_pte_init,
1339        .release_pud = xen_release_pte_init,
1340#endif  /* PAGETABLE_LEVELS == 4 */
1341
1342        .activate_mm = xen_activate_mm,
1343        .dup_mmap = xen_dup_mmap,
1344        .exit_mmap = xen_exit_mmap,
1345
1346        .lazy_mode = {
1347                .enter = paravirt_enter_lazy_mmu,
1348                .leave = xen_leave_lazy,
1349        },
1350
1351        .set_fixmap = xen_set_fixmap,
1352};
1353
1354static void xen_reboot(int reason)
1355{
1356        struct sched_shutdown r = { .reason = reason };
1357
1358#ifdef CONFIG_SMP
1359        smp_send_stop();
1360#endif
1361
1362        if (HYPERVISOR_sched_op(SCHEDOP_shutdown, &r))
1363                BUG();
1364}
1365
1366static void xen_restart(char *msg)
1367{
1368        xen_reboot(SHUTDOWN_reboot);
1369}
1370
1371static void xen_emergency_restart(void)
1372{
1373        xen_reboot(SHUTDOWN_reboot);
1374}
1375
1376static void xen_machine_halt(void)
1377{
1378        xen_reboot(SHUTDOWN_poweroff);
1379}
1380
1381static void xen_crash_shutdown(struct pt_regs *regs)
1382{
1383        xen_reboot(SHUTDOWN_crash);
1384}
1385
1386static const struct machine_ops __initdata xen_machine_ops = {
1387        .restart = xen_restart,
1388        .halt = xen_machine_halt,
1389        .power_off = xen_machine_halt,
1390        .shutdown = xen_machine_halt,
1391        .crash_shutdown = xen_crash_shutdown,
1392        .emergency_restart = xen_emergency_restart,
1393};
1394
1395
1396static void __init xen_reserve_top(void)
1397{
1398#ifdef CONFIG_X86_32
1399        unsigned long top = HYPERVISOR_VIRT_START;
1400        struct xen_platform_parameters pp;
1401
1402        if (HYPERVISOR_xen_version(XENVER_platform_parameters, &pp) == 0)
1403                top = pp.virt_start;
1404
1405        reserve_top_address(-top);
1406#endif  /* CONFIG_X86_32 */
1407}
1408
1409/*
1410 * Like __va(), but returns address in the kernel mapping (which is
1411 * all we have until the physical memory mapping has been set up.
1412 */
1413static void *__ka(phys_addr_t paddr)
1414{
1415#ifdef CONFIG_X86_64
1416        return (void *)(paddr + __START_KERNEL_map);
1417#else
1418        return __va(paddr);
1419#endif
1420}
1421
1422/* Convert a machine address to physical address */
1423static unsigned long m2p(phys_addr_t maddr)
1424{
1425        phys_addr_t paddr;
1426
1427        maddr &= PTE_PFN_MASK;
1428        paddr = mfn_to_pfn(maddr >> PAGE_SHIFT) << PAGE_SHIFT;
1429
1430        return paddr;
1431}
1432
1433/* Convert a machine address to kernel virtual */
1434static void *m2v(phys_addr_t maddr)
1435{
1436        return __ka(m2p(maddr));
1437}
1438
1439static void set_page_prot(void *addr, pgprot_t prot)
1440{
1441        unsigned long pfn = __pa(addr) >> PAGE_SHIFT;
1442        pte_t pte = pfn_pte(pfn, prot);
1443
1444        if (HYPERVISOR_update_va_mapping((unsigned long)addr, pte, 0))
1445                BUG();
1446}
1447
1448static __init void xen_map_identity_early(pmd_t *pmd, unsigned long max_pfn)
1449{
1450        unsigned pmdidx, pteidx;
1451        unsigned ident_pte;
1452        unsigned long pfn;
1453
1454        ident_pte = 0;
1455        pfn = 0;
1456        for(pmdidx = 0; pmdidx < PTRS_PER_PMD && pfn < max_pfn; pmdidx++) {
1457                pte_t *pte_page;
1458
1459                /* Reuse or allocate a page of ptes */
1460                if (pmd_present(pmd[pmdidx]))
1461                        pte_page = m2v(pmd[pmdidx].pmd);
1462                else {
1463                        /* Check for free pte pages */
1464                        if (ident_pte == ARRAY_SIZE(level1_ident_pgt))
1465                                break;
1466
1467                        pte_page = &level1_ident_pgt[ident_pte];
1468                        ident_pte += PTRS_PER_PTE;
1469
1470                        pmd[pmdidx] = __pmd(__pa(pte_page) | _PAGE_TABLE);
1471                }
1472
1473                /* Install mappings */
1474                for(pteidx = 0; pteidx < PTRS_PER_PTE; pteidx++, pfn++) {
1475                        pte_t pte;
1476
1477                        if (pfn > max_pfn_mapped)
1478                                max_pfn_mapped = pfn;
1479
1480                        if (!pte_none(pte_page[pteidx]))
1481                                continue;
1482
1483                        pte = pfn_pte(pfn, PAGE_KERNEL_EXEC);
1484                        pte_page[pteidx] = pte;
1485                }
1486        }
1487
1488        for(pteidx = 0; pteidx < ident_pte; pteidx += PTRS_PER_PTE)
1489                set_page_prot(&level1_ident_pgt[pteidx], PAGE_KERNEL_RO);
1490
1491        set_page_prot(pmd, PAGE_KERNEL_RO);
1492}
1493
1494#ifdef CONFIG_X86_64
1495static void convert_pfn_mfn(void *v)
1496{
1497        pte_t *pte = v;
1498        int i;
1499
1500        /* All levels are converted the same way, so just treat them
1501           as ptes. */
1502        for(i = 0; i < PTRS_PER_PTE; i++)
1503                pte[i] = xen_make_pte(pte[i].pte);
1504}
1505
1506/*
1507 * Set up the inital kernel pagetable.
1508 *
1509 * We can construct this by grafting the Xen provided pagetable into
1510 * head_64.S's preconstructed pagetables.  We copy the Xen L2's into
1511 * level2_ident_pgt, level2_kernel_pgt and level2_fixmap_pgt.  This
1512 * means that only the kernel has a physical mapping to start with -
1513 * but that's enough to get __va working.  We need to fill in the rest
1514 * of the physical mapping once some sort of allocator has been set
1515 * up.
1516 */
1517static __init pgd_t *xen_setup_kernel_pagetable(pgd_t *pgd, unsigned long max_pfn)
1518{
1519        pud_t *l3;
1520        pmd_t *l2;
1521
1522        /* Zap identity mapping */
1523        init_level4_pgt[0] = __pgd(0);
1524
1525        /* Pre-constructed entries are in pfn, so convert to mfn */
1526        convert_pfn_mfn(init_level4_pgt);
1527        convert_pfn_mfn(level3_ident_pgt);
1528        convert_pfn_mfn(level3_kernel_pgt);
1529
1530        l3 = m2v(pgd[pgd_index(__START_KERNEL_map)].pgd);
1531        l2 = m2v(l3[pud_index(__START_KERNEL_map)].pud);
1532
1533        memcpy(level2_ident_pgt, l2, sizeof(pmd_t) * PTRS_PER_PMD);
1534        memcpy(level2_kernel_pgt, l2, sizeof(pmd_t) * PTRS_PER_PMD);
1535
1536        l3 = m2v(pgd[pgd_index(__START_KERNEL_map + PMD_SIZE)].pgd);
1537        l2 = m2v(l3[pud_index(__START_KERNEL_map + PMD_SIZE)].pud);
1538        memcpy(level2_fixmap_pgt, l2, sizeof(pmd_t) * PTRS_PER_PMD);
1539
1540        /* Set up identity map */
1541        xen_map_identity_early(level2_ident_pgt, max_pfn);
1542
1543        /* Make pagetable pieces RO */
1544        set_page_prot(init_level4_pgt, PAGE_KERNEL_RO);
1545        set_page_prot(level3_ident_pgt, PAGE_KERNEL_RO);
1546        set_page_prot(level3_kernel_pgt, PAGE_KERNEL_RO);
1547        set_page_prot(level3_user_vsyscall, PAGE_KERNEL_RO);
1548        set_page_prot(level2_kernel_pgt, PAGE_KERNEL_RO);
1549        set_page_prot(level2_fixmap_pgt, PAGE_KERNEL_RO);
1550
1551        /* Pin down new L4 */
1552        pin_pagetable_pfn(MMUEXT_PIN_L4_TABLE,
1553                          PFN_DOWN(__pa_symbol(init_level4_pgt)));
1554
1555        /* Unpin Xen-provided one */
1556        pin_pagetable_pfn(MMUEXT_UNPIN_TABLE, PFN_DOWN(__pa(pgd)));
1557
1558        /* Switch over */
1559        pgd = init_level4_pgt;
1560
1561        /*
1562         * At this stage there can be no user pgd, and no page
1563         * structure to attach it to, so make sure we just set kernel
1564         * pgd.
1565         */
1566        xen_mc_batch();
1567        __xen_write_cr3(true, __pa(pgd));
1568        xen_mc_issue(PARAVIRT_LAZY_CPU);
1569
1570        reserve_early(__pa(xen_start_info->pt_base),
1571                      __pa(xen_start_info->pt_base +
1572                           xen_start_info->nr_pt_frames * PAGE_SIZE),
1573                      "XEN PAGETABLES");
1574
1575        return pgd;
1576}
1577#else   /* !CONFIG_X86_64 */
1578static pmd_t level2_kernel_pgt[PTRS_PER_PMD] __page_aligned_bss;
1579
1580static __init pgd_t *xen_setup_kernel_pagetable(pgd_t *pgd, unsigned long max_pfn)
1581{
1582        pmd_t *kernel_pmd;
1583
1584        init_pg_tables_start = __pa(pgd);
1585        init_pg_tables_end = __pa(pgd) + xen_start_info->nr_pt_frames*PAGE_SIZE;
1586        max_pfn_mapped = PFN_DOWN(init_pg_tables_end + 512*1024);
1587
1588        kernel_pmd = m2v(pgd[KERNEL_PGD_BOUNDARY].pgd);
1589        memcpy(level2_kernel_pgt, kernel_pmd, sizeof(pmd_t) * PTRS_PER_PMD);
1590
1591        xen_map_identity_early(level2_kernel_pgt, max_pfn);
1592
1593        memcpy(swapper_pg_dir, pgd, sizeof(pgd_t) * PTRS_PER_PGD);
1594        set_pgd(&swapper_pg_dir[KERNEL_PGD_BOUNDARY],
1595                        __pgd(__pa(level2_kernel_pgt) | _PAGE_PRESENT));
1596
1597        set_page_prot(level2_kernel_pgt, PAGE_KERNEL_RO);
1598        set_page_prot(swapper_pg_dir, PAGE_KERNEL_RO);
1599        set_page_prot(empty_zero_page, PAGE_KERNEL_RO);
1600
1601        pin_pagetable_pfn(MMUEXT_UNPIN_TABLE, PFN_DOWN(__pa(pgd)));
1602
1603        xen_write_cr3(__pa(swapper_pg_dir));
1604
1605        pin_pagetable_pfn(MMUEXT_PIN_L3_TABLE, PFN_DOWN(__pa(swapper_pg_dir)));
1606
1607        return swapper_pg_dir;
1608}
1609#endif  /* CONFIG_X86_64 */
1610
1611/* First C function to be called on Xen boot */
1612asmlinkage void __init xen_start_kernel(void)
1613{
1614        pgd_t *pgd;
1615
1616        if (!xen_start_info)
1617                return;
1618
1619        xen_domain_type = XEN_PV_DOMAIN;
1620
1621        BUG_ON(memcmp(xen_start_info->magic, "xen-3", 5) != 0);
1622
1623        xen_setup_features();
1624
1625        /* Install Xen paravirt ops */
1626        pv_info = xen_info;
1627        pv_init_ops = xen_init_ops;
1628        pv_time_ops = xen_time_ops;
1629        pv_cpu_ops = xen_cpu_ops;
1630        pv_apic_ops = xen_apic_ops;
1631        pv_mmu_ops = xen_mmu_ops;
1632
1633        xen_init_irq_ops();
1634
1635#ifdef CONFIG_X86_LOCAL_APIC
1636        /*
1637         * set up the basic apic ops.
1638         */
1639        apic_ops = &xen_basic_apic_ops;
1640#endif
1641
1642        if (xen_feature(XENFEAT_mmu_pt_update_preserve_ad)) {
1643                pv_mmu_ops.ptep_modify_prot_start = xen_ptep_modify_prot_start;
1644                pv_mmu_ops.ptep_modify_prot_commit = xen_ptep_modify_prot_commit;
1645        }
1646
1647        machine_ops = xen_machine_ops;
1648
1649#ifdef CONFIG_X86_64
1650        /* Disable until direct per-cpu data access. */
1651        have_vcpu_info_placement = 0;
1652        x86_64_init_pda();
1653#endif
1654
1655        xen_smp_init();
1656
1657        /* Get mfn list */
1658        if (!xen_feature(XENFEAT_auto_translated_physmap))
1659                xen_build_dynamic_phys_to_machine();
1660
1661        pgd = (pgd_t *)xen_start_info->pt_base;
1662
1663        /* Prevent unwanted bits from being set in PTEs. */
1664        __supported_pte_mask &= ~_PAGE_GLOBAL;
1665        if (!xen_initial_domain())
1666                __supported_pte_mask &= ~(_PAGE_PWT | _PAGE_PCD);
1667
1668        /* Don't do the full vcpu_info placement stuff until we have a
1669           possible map and a non-dummy shared_info. */
1670        per_cpu(xen_vcpu, 0) = &HYPERVISOR_shared_info->vcpu_info[0];
1671
1672        xen_raw_console_write("mapping kernel into physical memory\n");
1673        pgd = xen_setup_kernel_pagetable(pgd, xen_start_info->nr_pages);
1674
1675        init_mm.pgd = pgd;
1676
1677        /* keep using Xen gdt for now; no urgent need to change it */
1678
1679        pv_info.kernel_rpl = 1;
1680        if (xen_feature(XENFEAT_supervisor_mode_kernel))
1681                pv_info.kernel_rpl = 0;
1682
1683        /* set the limit of our address space */
1684        xen_reserve_top();
1685
1686#ifdef CONFIG_X86_32
1687        /* set up basic CPUID stuff */
1688        cpu_detect(&new_cpu_data);
1689        new_cpu_data.hard_math = 1;
1690        new_cpu_data.x86_capability[0] = cpuid_edx(1);
1691#endif
1692
1693        /* Poke various useful things into boot_params */
1694        boot_params.hdr.type_of_loader = (9 << 4) | 0;
1695        boot_params.hdr.ramdisk_image = xen_start_info->mod_start
1696                ? __pa(xen_start_info->mod_start) : 0;
1697        boot_params.hdr.ramdisk_size = xen_start_info->mod_len;
1698        boot_params.hdr.cmd_line_ptr = __pa(xen_start_info->cmd_line);
1699
1700        if (!xen_initial_domain()) {
1701                add_preferred_console("xenboot", 0, NULL);
1702                add_preferred_console("tty", 0, NULL);
1703                add_preferred_console("hvc", 0, NULL);
1704        }
1705
1706        xen_raw_console_write("about to get started...\n");
1707
1708        /* Start the world */
1709#ifdef CONFIG_X86_32
1710        i386_start_kernel();
1711#else
1712        x86_64_start_reservations((char *)__pa_symbol(&boot_params));
1713#endif
1714}
1715