linux/arch/x86/xen/mmu_pv.c
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   1// SPDX-License-Identifier: GPL-2.0
   2
   3/*
   4 * Xen mmu operations
   5 *
   6 * This file contains the various mmu fetch and update operations.
   7 * The most important job they must perform is the mapping between the
   8 * domain's pfn and the overall machine mfns.
   9 *
  10 * Xen allows guests to directly update the pagetable, in a controlled
  11 * fashion.  In other words, the guest modifies the same pagetable
  12 * that the CPU actually uses, which eliminates the overhead of having
  13 * a separate shadow pagetable.
  14 *
  15 * In order to allow this, it falls on the guest domain to map its
  16 * notion of a "physical" pfn - which is just a domain-local linear
  17 * address - into a real "machine address" which the CPU's MMU can
  18 * use.
  19 *
  20 * A pgd_t/pmd_t/pte_t will typically contain an mfn, and so can be
  21 * inserted directly into the pagetable.  When creating a new
  22 * pte/pmd/pgd, it converts the passed pfn into an mfn.  Conversely,
  23 * when reading the content back with __(pgd|pmd|pte)_val, it converts
  24 * the mfn back into a pfn.
  25 *
  26 * The other constraint is that all pages which make up a pagetable
  27 * must be mapped read-only in the guest.  This prevents uncontrolled
  28 * guest updates to the pagetable.  Xen strictly enforces this, and
  29 * will disallow any pagetable update which will end up mapping a
  30 * pagetable page RW, and will disallow using any writable page as a
  31 * pagetable.
  32 *
  33 * Naively, when loading %cr3 with the base of a new pagetable, Xen
  34 * would need to validate the whole pagetable before going on.
  35 * Naturally, this is quite slow.  The solution is to "pin" a
  36 * pagetable, which enforces all the constraints on the pagetable even
  37 * when it is not actively in use.  This menas that Xen can be assured
  38 * that it is still valid when you do load it into %cr3, and doesn't
  39 * need to revalidate it.
  40 *
  41 * Jeremy Fitzhardinge <jeremy@xensource.com>, XenSource Inc, 2007
  42 */
  43#include <linux/sched/mm.h>
  44#include <linux/highmem.h>
  45#include <linux/debugfs.h>
  46#include <linux/bug.h>
  47#include <linux/vmalloc.h>
  48#include <linux/export.h>
  49#include <linux/init.h>
  50#include <linux/gfp.h>
  51#include <linux/memblock.h>
  52#include <linux/seq_file.h>
  53#include <linux/crash_dump.h>
  54#ifdef CONFIG_KEXEC_CORE
  55#include <linux/kexec.h>
  56#endif
  57
  58#include <trace/events/xen.h>
  59
  60#include <asm/pgtable.h>
  61#include <asm/tlbflush.h>
  62#include <asm/fixmap.h>
  63#include <asm/mmu_context.h>
  64#include <asm/setup.h>
  65#include <asm/paravirt.h>
  66#include <asm/e820/api.h>
  67#include <asm/linkage.h>
  68#include <asm/page.h>
  69#include <asm/init.h>
  70#include <asm/pat.h>
  71#include <asm/smp.h>
  72#include <asm/tlb.h>
  73
  74#include <asm/xen/hypercall.h>
  75#include <asm/xen/hypervisor.h>
  76
  77#include <xen/xen.h>
  78#include <xen/page.h>
  79#include <xen/interface/xen.h>
  80#include <xen/interface/hvm/hvm_op.h>
  81#include <xen/interface/version.h>
  82#include <xen/interface/memory.h>
  83#include <xen/hvc-console.h>
  84
  85#include "multicalls.h"
  86#include "mmu.h"
  87#include "debugfs.h"
  88
  89#ifdef CONFIG_X86_32
  90/*
  91 * Identity map, in addition to plain kernel map.  This needs to be
  92 * large enough to allocate page table pages to allocate the rest.
  93 * Each page can map 2MB.
  94 */
  95#define LEVEL1_IDENT_ENTRIES    (PTRS_PER_PTE * 4)
  96static RESERVE_BRK_ARRAY(pte_t, level1_ident_pgt, LEVEL1_IDENT_ENTRIES);
  97#endif
  98#ifdef CONFIG_X86_64
  99/* l3 pud for userspace vsyscall mapping */
 100static pud_t level3_user_vsyscall[PTRS_PER_PUD] __page_aligned_bss;
 101#endif /* CONFIG_X86_64 */
 102
 103/*
 104 * Protects atomic reservation decrease/increase against concurrent increases.
 105 * Also protects non-atomic updates of current_pages and balloon lists.
 106 */
 107static DEFINE_SPINLOCK(xen_reservation_lock);
 108
 109/*
 110 * Note about cr3 (pagetable base) values:
 111 *
 112 * xen_cr3 contains the current logical cr3 value; it contains the
 113 * last set cr3.  This may not be the current effective cr3, because
 114 * its update may be being lazily deferred.  However, a vcpu looking
 115 * at its own cr3 can use this value knowing that it everything will
 116 * be self-consistent.
 117 *
 118 * xen_current_cr3 contains the actual vcpu cr3; it is set once the
 119 * hypercall to set the vcpu cr3 is complete (so it may be a little
 120 * out of date, but it will never be set early).  If one vcpu is
 121 * looking at another vcpu's cr3 value, it should use this variable.
 122 */
 123DEFINE_PER_CPU(unsigned long, xen_cr3);  /* cr3 stored as physaddr */
 124DEFINE_PER_CPU(unsigned long, xen_current_cr3);  /* actual vcpu cr3 */
 125
 126static phys_addr_t xen_pt_base, xen_pt_size __initdata;
 127
 128static DEFINE_STATIC_KEY_FALSE(xen_struct_pages_ready);
 129
 130/*
 131 * Just beyond the highest usermode address.  STACK_TOP_MAX has a
 132 * redzone above it, so round it up to a PGD boundary.
 133 */
 134#define USER_LIMIT      ((STACK_TOP_MAX + PGDIR_SIZE - 1) & PGDIR_MASK)
 135
 136void make_lowmem_page_readonly(void *vaddr)
 137{
 138        pte_t *pte, ptev;
 139        unsigned long address = (unsigned long)vaddr;
 140        unsigned int level;
 141
 142        pte = lookup_address(address, &level);
 143        if (pte == NULL)
 144                return;         /* vaddr missing */
 145
 146        ptev = pte_wrprotect(*pte);
 147
 148        if (HYPERVISOR_update_va_mapping(address, ptev, 0))
 149                BUG();
 150}
 151
 152void make_lowmem_page_readwrite(void *vaddr)
 153{
 154        pte_t *pte, ptev;
 155        unsigned long address = (unsigned long)vaddr;
 156        unsigned int level;
 157
 158        pte = lookup_address(address, &level);
 159        if (pte == NULL)
 160                return;         /* vaddr missing */
 161
 162        ptev = pte_mkwrite(*pte);
 163
 164        if (HYPERVISOR_update_va_mapping(address, ptev, 0))
 165                BUG();
 166}
 167
 168
 169/*
 170 * During early boot all page table pages are pinned, but we do not have struct
 171 * pages, so return true until struct pages are ready.
 172 */
 173static bool xen_page_pinned(void *ptr)
 174{
 175        if (static_branch_likely(&xen_struct_pages_ready)) {
 176                struct page *page = virt_to_page(ptr);
 177
 178                return PagePinned(page);
 179        }
 180        return true;
 181}
 182
 183static void xen_extend_mmu_update(const struct mmu_update *update)
 184{
 185        struct multicall_space mcs;
 186        struct mmu_update *u;
 187
 188        mcs = xen_mc_extend_args(__HYPERVISOR_mmu_update, sizeof(*u));
 189
 190        if (mcs.mc != NULL) {
 191                mcs.mc->args[1]++;
 192        } else {
 193                mcs = __xen_mc_entry(sizeof(*u));
 194                MULTI_mmu_update(mcs.mc, mcs.args, 1, NULL, DOMID_SELF);
 195        }
 196
 197        u = mcs.args;
 198        *u = *update;
 199}
 200
 201static void xen_extend_mmuext_op(const struct mmuext_op *op)
 202{
 203        struct multicall_space mcs;
 204        struct mmuext_op *u;
 205
 206        mcs = xen_mc_extend_args(__HYPERVISOR_mmuext_op, sizeof(*u));
 207
 208        if (mcs.mc != NULL) {
 209                mcs.mc->args[1]++;
 210        } else {
 211                mcs = __xen_mc_entry(sizeof(*u));
 212                MULTI_mmuext_op(mcs.mc, mcs.args, 1, NULL, DOMID_SELF);
 213        }
 214
 215        u = mcs.args;
 216        *u = *op;
 217}
 218
 219static void xen_set_pmd_hyper(pmd_t *ptr, pmd_t val)
 220{
 221        struct mmu_update u;
 222
 223        preempt_disable();
 224
 225        xen_mc_batch();
 226
 227        /* ptr may be ioremapped for 64-bit pagetable setup */
 228        u.ptr = arbitrary_virt_to_machine(ptr).maddr;
 229        u.val = pmd_val_ma(val);
 230        xen_extend_mmu_update(&u);
 231
 232        xen_mc_issue(PARAVIRT_LAZY_MMU);
 233
 234        preempt_enable();
 235}
 236
 237static void xen_set_pmd(pmd_t *ptr, pmd_t val)
 238{
 239        trace_xen_mmu_set_pmd(ptr, val);
 240
 241        /* If page is not pinned, we can just update the entry
 242           directly */
 243        if (!xen_page_pinned(ptr)) {
 244                *ptr = val;
 245                return;
 246        }
 247
 248        xen_set_pmd_hyper(ptr, val);
 249}
 250
 251/*
 252 * Associate a virtual page frame with a given physical page frame
 253 * and protection flags for that frame.
 254 */
 255void set_pte_mfn(unsigned long vaddr, unsigned long mfn, pgprot_t flags)
 256{
 257        set_pte_vaddr(vaddr, mfn_pte(mfn, flags));
 258}
 259
 260static bool xen_batched_set_pte(pte_t *ptep, pte_t pteval)
 261{
 262        struct mmu_update u;
 263
 264        if (paravirt_get_lazy_mode() != PARAVIRT_LAZY_MMU)
 265                return false;
 266
 267        xen_mc_batch();
 268
 269        u.ptr = virt_to_machine(ptep).maddr | MMU_NORMAL_PT_UPDATE;
 270        u.val = pte_val_ma(pteval);
 271        xen_extend_mmu_update(&u);
 272
 273        xen_mc_issue(PARAVIRT_LAZY_MMU);
 274
 275        return true;
 276}
 277
 278static inline void __xen_set_pte(pte_t *ptep, pte_t pteval)
 279{
 280        if (!xen_batched_set_pte(ptep, pteval)) {
 281                /*
 282                 * Could call native_set_pte() here and trap and
 283                 * emulate the PTE write but with 32-bit guests this
 284                 * needs two traps (one for each of the two 32-bit
 285                 * words in the PTE) so do one hypercall directly
 286                 * instead.
 287                 */
 288                struct mmu_update u;
 289
 290                u.ptr = virt_to_machine(ptep).maddr | MMU_NORMAL_PT_UPDATE;
 291                u.val = pte_val_ma(pteval);
 292                HYPERVISOR_mmu_update(&u, 1, NULL, DOMID_SELF);
 293        }
 294}
 295
 296static void xen_set_pte(pte_t *ptep, pte_t pteval)
 297{
 298        trace_xen_mmu_set_pte(ptep, pteval);
 299        __xen_set_pte(ptep, pteval);
 300}
 301
 302static void xen_set_pte_at(struct mm_struct *mm, unsigned long addr,
 303                    pte_t *ptep, pte_t pteval)
 304{
 305        trace_xen_mmu_set_pte_at(mm, addr, ptep, pteval);
 306        __xen_set_pte(ptep, pteval);
 307}
 308
 309pte_t xen_ptep_modify_prot_start(struct vm_area_struct *vma,
 310                                 unsigned long addr, pte_t *ptep)
 311{
 312        /* Just return the pte as-is.  We preserve the bits on commit */
 313        trace_xen_mmu_ptep_modify_prot_start(vma->vm_mm, addr, ptep, *ptep);
 314        return *ptep;
 315}
 316
 317void xen_ptep_modify_prot_commit(struct vm_area_struct *vma, unsigned long addr,
 318                                 pte_t *ptep, pte_t pte)
 319{
 320        struct mmu_update u;
 321
 322        trace_xen_mmu_ptep_modify_prot_commit(vma->vm_mm, addr, ptep, pte);
 323        xen_mc_batch();
 324
 325        u.ptr = virt_to_machine(ptep).maddr | MMU_PT_UPDATE_PRESERVE_AD;
 326        u.val = pte_val_ma(pte);
 327        xen_extend_mmu_update(&u);
 328
 329        xen_mc_issue(PARAVIRT_LAZY_MMU);
 330}
 331
 332/* Assume pteval_t is equivalent to all the other *val_t types. */
 333static pteval_t pte_mfn_to_pfn(pteval_t val)
 334{
 335        if (val & _PAGE_PRESENT) {
 336                unsigned long mfn = (val & XEN_PTE_MFN_MASK) >> PAGE_SHIFT;
 337                unsigned long pfn = mfn_to_pfn(mfn);
 338
 339                pteval_t flags = val & PTE_FLAGS_MASK;
 340                if (unlikely(pfn == ~0))
 341                        val = flags & ~_PAGE_PRESENT;
 342                else
 343                        val = ((pteval_t)pfn << PAGE_SHIFT) | flags;
 344        }
 345
 346        return val;
 347}
 348
 349static pteval_t pte_pfn_to_mfn(pteval_t val)
 350{
 351        if (val & _PAGE_PRESENT) {
 352                unsigned long pfn = (val & PTE_PFN_MASK) >> PAGE_SHIFT;
 353                pteval_t flags = val & PTE_FLAGS_MASK;
 354                unsigned long mfn;
 355
 356                mfn = __pfn_to_mfn(pfn);
 357
 358                /*
 359                 * If there's no mfn for the pfn, then just create an
 360                 * empty non-present pte.  Unfortunately this loses
 361                 * information about the original pfn, so
 362                 * pte_mfn_to_pfn is asymmetric.
 363                 */
 364                if (unlikely(mfn == INVALID_P2M_ENTRY)) {
 365                        mfn = 0;
 366                        flags = 0;
 367                } else
 368                        mfn &= ~(FOREIGN_FRAME_BIT | IDENTITY_FRAME_BIT);
 369                val = ((pteval_t)mfn << PAGE_SHIFT) | flags;
 370        }
 371
 372        return val;
 373}
 374
 375__visible pteval_t xen_pte_val(pte_t pte)
 376{
 377        pteval_t pteval = pte.pte;
 378
 379        return pte_mfn_to_pfn(pteval);
 380}
 381PV_CALLEE_SAVE_REGS_THUNK(xen_pte_val);
 382
 383__visible pgdval_t xen_pgd_val(pgd_t pgd)
 384{
 385        return pte_mfn_to_pfn(pgd.pgd);
 386}
 387PV_CALLEE_SAVE_REGS_THUNK(xen_pgd_val);
 388
 389__visible pte_t xen_make_pte(pteval_t pte)
 390{
 391        pte = pte_pfn_to_mfn(pte);
 392
 393        return native_make_pte(pte);
 394}
 395PV_CALLEE_SAVE_REGS_THUNK(xen_make_pte);
 396
 397__visible pgd_t xen_make_pgd(pgdval_t pgd)
 398{
 399        pgd = pte_pfn_to_mfn(pgd);
 400        return native_make_pgd(pgd);
 401}
 402PV_CALLEE_SAVE_REGS_THUNK(xen_make_pgd);
 403
 404__visible pmdval_t xen_pmd_val(pmd_t pmd)
 405{
 406        return pte_mfn_to_pfn(pmd.pmd);
 407}
 408PV_CALLEE_SAVE_REGS_THUNK(xen_pmd_val);
 409
 410static void xen_set_pud_hyper(pud_t *ptr, pud_t val)
 411{
 412        struct mmu_update u;
 413
 414        preempt_disable();
 415
 416        xen_mc_batch();
 417
 418        /* ptr may be ioremapped for 64-bit pagetable setup */
 419        u.ptr = arbitrary_virt_to_machine(ptr).maddr;
 420        u.val = pud_val_ma(val);
 421        xen_extend_mmu_update(&u);
 422
 423        xen_mc_issue(PARAVIRT_LAZY_MMU);
 424
 425        preempt_enable();
 426}
 427
 428static void xen_set_pud(pud_t *ptr, pud_t val)
 429{
 430        trace_xen_mmu_set_pud(ptr, val);
 431
 432        /* If page is not pinned, we can just update the entry
 433           directly */
 434        if (!xen_page_pinned(ptr)) {
 435                *ptr = val;
 436                return;
 437        }
 438
 439        xen_set_pud_hyper(ptr, val);
 440}
 441
 442#ifdef CONFIG_X86_PAE
 443static void xen_set_pte_atomic(pte_t *ptep, pte_t pte)
 444{
 445        trace_xen_mmu_set_pte_atomic(ptep, pte);
 446        __xen_set_pte(ptep, pte);
 447}
 448
 449static void xen_pte_clear(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
 450{
 451        trace_xen_mmu_pte_clear(mm, addr, ptep);
 452        __xen_set_pte(ptep, native_make_pte(0));
 453}
 454
 455static void xen_pmd_clear(pmd_t *pmdp)
 456{
 457        trace_xen_mmu_pmd_clear(pmdp);
 458        set_pmd(pmdp, __pmd(0));
 459}
 460#endif  /* CONFIG_X86_PAE */
 461
 462__visible pmd_t xen_make_pmd(pmdval_t pmd)
 463{
 464        pmd = pte_pfn_to_mfn(pmd);
 465        return native_make_pmd(pmd);
 466}
 467PV_CALLEE_SAVE_REGS_THUNK(xen_make_pmd);
 468
 469#ifdef CONFIG_X86_64
 470__visible pudval_t xen_pud_val(pud_t pud)
 471{
 472        return pte_mfn_to_pfn(pud.pud);
 473}
 474PV_CALLEE_SAVE_REGS_THUNK(xen_pud_val);
 475
 476__visible pud_t xen_make_pud(pudval_t pud)
 477{
 478        pud = pte_pfn_to_mfn(pud);
 479
 480        return native_make_pud(pud);
 481}
 482PV_CALLEE_SAVE_REGS_THUNK(xen_make_pud);
 483
 484static pgd_t *xen_get_user_pgd(pgd_t *pgd)
 485{
 486        pgd_t *pgd_page = (pgd_t *)(((unsigned long)pgd) & PAGE_MASK);
 487        unsigned offset = pgd - pgd_page;
 488        pgd_t *user_ptr = NULL;
 489
 490        if (offset < pgd_index(USER_LIMIT)) {
 491                struct page *page = virt_to_page(pgd_page);
 492                user_ptr = (pgd_t *)page->private;
 493                if (user_ptr)
 494                        user_ptr += offset;
 495        }
 496
 497        return user_ptr;
 498}
 499
 500static void __xen_set_p4d_hyper(p4d_t *ptr, p4d_t val)
 501{
 502        struct mmu_update u;
 503
 504        u.ptr = virt_to_machine(ptr).maddr;
 505        u.val = p4d_val_ma(val);
 506        xen_extend_mmu_update(&u);
 507}
 508
 509/*
 510 * Raw hypercall-based set_p4d, intended for in early boot before
 511 * there's a page structure.  This implies:
 512 *  1. The only existing pagetable is the kernel's
 513 *  2. It is always pinned
 514 *  3. It has no user pagetable attached to it
 515 */
 516static void __init xen_set_p4d_hyper(p4d_t *ptr, p4d_t val)
 517{
 518        preempt_disable();
 519
 520        xen_mc_batch();
 521
 522        __xen_set_p4d_hyper(ptr, val);
 523
 524        xen_mc_issue(PARAVIRT_LAZY_MMU);
 525
 526        preempt_enable();
 527}
 528
 529static void xen_set_p4d(p4d_t *ptr, p4d_t val)
 530{
 531        pgd_t *user_ptr = xen_get_user_pgd((pgd_t *)ptr);
 532        pgd_t pgd_val;
 533
 534        trace_xen_mmu_set_p4d(ptr, (p4d_t *)user_ptr, val);
 535
 536        /* If page is not pinned, we can just update the entry
 537           directly */
 538        if (!xen_page_pinned(ptr)) {
 539                *ptr = val;
 540                if (user_ptr) {
 541                        WARN_ON(xen_page_pinned(user_ptr));
 542                        pgd_val.pgd = p4d_val_ma(val);
 543                        *user_ptr = pgd_val;
 544                }
 545                return;
 546        }
 547
 548        /* If it's pinned, then we can at least batch the kernel and
 549           user updates together. */
 550        xen_mc_batch();
 551
 552        __xen_set_p4d_hyper(ptr, val);
 553        if (user_ptr)
 554                __xen_set_p4d_hyper((p4d_t *)user_ptr, val);
 555
 556        xen_mc_issue(PARAVIRT_LAZY_MMU);
 557}
 558
 559#if CONFIG_PGTABLE_LEVELS >= 5
 560__visible p4dval_t xen_p4d_val(p4d_t p4d)
 561{
 562        return pte_mfn_to_pfn(p4d.p4d);
 563}
 564PV_CALLEE_SAVE_REGS_THUNK(xen_p4d_val);
 565
 566__visible p4d_t xen_make_p4d(p4dval_t p4d)
 567{
 568        p4d = pte_pfn_to_mfn(p4d);
 569
 570        return native_make_p4d(p4d);
 571}
 572PV_CALLEE_SAVE_REGS_THUNK(xen_make_p4d);
 573#endif  /* CONFIG_PGTABLE_LEVELS >= 5 */
 574#endif  /* CONFIG_X86_64 */
 575
 576static int xen_pmd_walk(struct mm_struct *mm, pmd_t *pmd,
 577                int (*func)(struct mm_struct *mm, struct page *, enum pt_level),
 578                bool last, unsigned long limit)
 579{
 580        int i, nr, flush = 0;
 581
 582        nr = last ? pmd_index(limit) + 1 : PTRS_PER_PMD;
 583        for (i = 0; i < nr; i++) {
 584                if (!pmd_none(pmd[i]))
 585                        flush |= (*func)(mm, pmd_page(pmd[i]), PT_PTE);
 586        }
 587        return flush;
 588}
 589
 590static int xen_pud_walk(struct mm_struct *mm, pud_t *pud,
 591                int (*func)(struct mm_struct *mm, struct page *, enum pt_level),
 592                bool last, unsigned long limit)
 593{
 594        int i, nr, flush = 0;
 595
 596        nr = last ? pud_index(limit) + 1 : PTRS_PER_PUD;
 597        for (i = 0; i < nr; i++) {
 598                pmd_t *pmd;
 599
 600                if (pud_none(pud[i]))
 601                        continue;
 602
 603                pmd = pmd_offset(&pud[i], 0);
 604                if (PTRS_PER_PMD > 1)
 605                        flush |= (*func)(mm, virt_to_page(pmd), PT_PMD);
 606                flush |= xen_pmd_walk(mm, pmd, func,
 607                                last && i == nr - 1, limit);
 608        }
 609        return flush;
 610}
 611
 612static int xen_p4d_walk(struct mm_struct *mm, p4d_t *p4d,
 613                int (*func)(struct mm_struct *mm, struct page *, enum pt_level),
 614                bool last, unsigned long limit)
 615{
 616        int flush = 0;
 617        pud_t *pud;
 618
 619
 620        if (p4d_none(*p4d))
 621                return flush;
 622
 623        pud = pud_offset(p4d, 0);
 624        if (PTRS_PER_PUD > 1)
 625                flush |= (*func)(mm, virt_to_page(pud), PT_PUD);
 626        flush |= xen_pud_walk(mm, pud, func, last, limit);
 627        return flush;
 628}
 629
 630/*
 631 * (Yet another) pagetable walker.  This one is intended for pinning a
 632 * pagetable.  This means that it walks a pagetable and calls the
 633 * callback function on each page it finds making up the page table,
 634 * at every level.  It walks the entire pagetable, but it only bothers
 635 * pinning pte pages which are below limit.  In the normal case this
 636 * will be STACK_TOP_MAX, but at boot we need to pin up to
 637 * FIXADDR_TOP.
 638 *
 639 * For 32-bit the important bit is that we don't pin beyond there,
 640 * because then we start getting into Xen's ptes.
 641 *
 642 * For 64-bit, we must skip the Xen hole in the middle of the address
 643 * space, just after the big x86-64 virtual hole.
 644 */
 645static int __xen_pgd_walk(struct mm_struct *mm, pgd_t *pgd,
 646                          int (*func)(struct mm_struct *mm, struct page *,
 647                                      enum pt_level),
 648                          unsigned long limit)
 649{
 650        int i, nr, flush = 0;
 651        unsigned hole_low = 0, hole_high = 0;
 652
 653        /* The limit is the last byte to be touched */
 654        limit--;
 655        BUG_ON(limit >= FIXADDR_TOP);
 656
 657#ifdef CONFIG_X86_64
 658        /*
 659         * 64-bit has a great big hole in the middle of the address
 660         * space, which contains the Xen mappings.
 661         */
 662        hole_low = pgd_index(GUARD_HOLE_BASE_ADDR);
 663        hole_high = pgd_index(GUARD_HOLE_END_ADDR);
 664#endif
 665
 666        nr = pgd_index(limit) + 1;
 667        for (i = 0; i < nr; i++) {
 668                p4d_t *p4d;
 669
 670                if (i >= hole_low && i < hole_high)
 671                        continue;
 672
 673                if (pgd_none(pgd[i]))
 674                        continue;
 675
 676                p4d = p4d_offset(&pgd[i], 0);
 677                flush |= xen_p4d_walk(mm, p4d, func, i == nr - 1, limit);
 678        }
 679
 680        /* Do the top level last, so that the callbacks can use it as
 681           a cue to do final things like tlb flushes. */
 682        flush |= (*func)(mm, virt_to_page(pgd), PT_PGD);
 683
 684        return flush;
 685}
 686
 687static int xen_pgd_walk(struct mm_struct *mm,
 688                        int (*func)(struct mm_struct *mm, struct page *,
 689                                    enum pt_level),
 690                        unsigned long limit)
 691{
 692        return __xen_pgd_walk(mm, mm->pgd, func, limit);
 693}
 694
 695/* If we're using split pte locks, then take the page's lock and
 696   return a pointer to it.  Otherwise return NULL. */
 697static spinlock_t *xen_pte_lock(struct page *page, struct mm_struct *mm)
 698{
 699        spinlock_t *ptl = NULL;
 700
 701#if USE_SPLIT_PTE_PTLOCKS
 702        ptl = ptlock_ptr(page);
 703        spin_lock_nest_lock(ptl, &mm->page_table_lock);
 704#endif
 705
 706        return ptl;
 707}
 708
 709static void xen_pte_unlock(void *v)
 710{
 711        spinlock_t *ptl = v;
 712        spin_unlock(ptl);
 713}
 714
 715static void xen_do_pin(unsigned level, unsigned long pfn)
 716{
 717        struct mmuext_op op;
 718
 719        op.cmd = level;
 720        op.arg1.mfn = pfn_to_mfn(pfn);
 721
 722        xen_extend_mmuext_op(&op);
 723}
 724
 725static int xen_pin_page(struct mm_struct *mm, struct page *page,
 726                        enum pt_level level)
 727{
 728        unsigned pgfl = TestSetPagePinned(page);
 729        int flush;
 730
 731        if (pgfl)
 732                flush = 0;              /* already pinned */
 733        else if (PageHighMem(page))
 734                /* kmaps need flushing if we found an unpinned
 735                   highpage */
 736                flush = 1;
 737        else {
 738                void *pt = lowmem_page_address(page);
 739                unsigned long pfn = page_to_pfn(page);
 740                struct multicall_space mcs = __xen_mc_entry(0);
 741                spinlock_t *ptl;
 742
 743                flush = 0;
 744
 745                /*
 746                 * We need to hold the pagetable lock between the time
 747                 * we make the pagetable RO and when we actually pin
 748                 * it.  If we don't, then other users may come in and
 749                 * attempt to update the pagetable by writing it,
 750                 * which will fail because the memory is RO but not
 751                 * pinned, so Xen won't do the trap'n'emulate.
 752                 *
 753                 * If we're using split pte locks, we can't hold the
 754                 * entire pagetable's worth of locks during the
 755                 * traverse, because we may wrap the preempt count (8
 756                 * bits).  The solution is to mark RO and pin each PTE
 757                 * page while holding the lock.  This means the number
 758                 * of locks we end up holding is never more than a
 759                 * batch size (~32 entries, at present).
 760                 *
 761                 * If we're not using split pte locks, we needn't pin
 762                 * the PTE pages independently, because we're
 763                 * protected by the overall pagetable lock.
 764                 */
 765                ptl = NULL;
 766                if (level == PT_PTE)
 767                        ptl = xen_pte_lock(page, mm);
 768
 769                MULTI_update_va_mapping(mcs.mc, (unsigned long)pt,
 770                                        pfn_pte(pfn, PAGE_KERNEL_RO),
 771                                        level == PT_PGD ? UVMF_TLB_FLUSH : 0);
 772
 773                if (ptl) {
 774                        xen_do_pin(MMUEXT_PIN_L1_TABLE, pfn);
 775
 776                        /* Queue a deferred unlock for when this batch
 777                           is completed. */
 778                        xen_mc_callback(xen_pte_unlock, ptl);
 779                }
 780        }
 781
 782        return flush;
 783}
 784
 785/* This is called just after a mm has been created, but it has not
 786   been used yet.  We need to make sure that its pagetable is all
 787   read-only, and can be pinned. */
 788static void __xen_pgd_pin(struct mm_struct *mm, pgd_t *pgd)
 789{
 790        trace_xen_mmu_pgd_pin(mm, pgd);
 791
 792        xen_mc_batch();
 793
 794        if (__xen_pgd_walk(mm, pgd, xen_pin_page, USER_LIMIT)) {
 795                /* re-enable interrupts for flushing */
 796                xen_mc_issue(0);
 797
 798                kmap_flush_unused();
 799
 800                xen_mc_batch();
 801        }
 802
 803#ifdef CONFIG_X86_64
 804        {
 805                pgd_t *user_pgd = xen_get_user_pgd(pgd);
 806
 807                xen_do_pin(MMUEXT_PIN_L4_TABLE, PFN_DOWN(__pa(pgd)));
 808
 809                if (user_pgd) {
 810                        xen_pin_page(mm, virt_to_page(user_pgd), PT_PGD);
 811                        xen_do_pin(MMUEXT_PIN_L4_TABLE,
 812                                   PFN_DOWN(__pa(user_pgd)));
 813                }
 814        }
 815#else /* CONFIG_X86_32 */
 816#ifdef CONFIG_X86_PAE
 817        /* Need to make sure unshared kernel PMD is pinnable */
 818        xen_pin_page(mm, pgd_page(pgd[pgd_index(TASK_SIZE)]),
 819                     PT_PMD);
 820#endif
 821        xen_do_pin(MMUEXT_PIN_L3_TABLE, PFN_DOWN(__pa(pgd)));
 822#endif /* CONFIG_X86_64 */
 823        xen_mc_issue(0);
 824}
 825
 826static void xen_pgd_pin(struct mm_struct *mm)
 827{
 828        __xen_pgd_pin(mm, mm->pgd);
 829}
 830
 831/*
 832 * On save, we need to pin all pagetables to make sure they get their
 833 * mfns turned into pfns.  Search the list for any unpinned pgds and pin
 834 * them (unpinned pgds are not currently in use, probably because the
 835 * process is under construction or destruction).
 836 *
 837 * Expected to be called in stop_machine() ("equivalent to taking
 838 * every spinlock in the system"), so the locking doesn't really
 839 * matter all that much.
 840 */
 841void xen_mm_pin_all(void)
 842{
 843        struct page *page;
 844
 845        spin_lock(&pgd_lock);
 846
 847        list_for_each_entry(page, &pgd_list, lru) {
 848                if (!PagePinned(page)) {
 849                        __xen_pgd_pin(&init_mm, (pgd_t *)page_address(page));
 850                        SetPageSavePinned(page);
 851                }
 852        }
 853
 854        spin_unlock(&pgd_lock);
 855}
 856
 857static int __init xen_mark_pinned(struct mm_struct *mm, struct page *page,
 858                                  enum pt_level level)
 859{
 860        SetPagePinned(page);
 861        return 0;
 862}
 863
 864/*
 865 * The init_mm pagetable is really pinned as soon as its created, but
 866 * that's before we have page structures to store the bits.  So do all
 867 * the book-keeping now once struct pages for allocated pages are
 868 * initialized. This happens only after memblock_free_all() is called.
 869 */
 870static void __init xen_after_bootmem(void)
 871{
 872        static_branch_enable(&xen_struct_pages_ready);
 873#ifdef CONFIG_X86_64
 874        SetPagePinned(virt_to_page(level3_user_vsyscall));
 875#endif
 876        xen_pgd_walk(&init_mm, xen_mark_pinned, FIXADDR_TOP);
 877}
 878
 879static int xen_unpin_page(struct mm_struct *mm, struct page *page,
 880                          enum pt_level level)
 881{
 882        unsigned pgfl = TestClearPagePinned(page);
 883
 884        if (pgfl && !PageHighMem(page)) {
 885                void *pt = lowmem_page_address(page);
 886                unsigned long pfn = page_to_pfn(page);
 887                spinlock_t *ptl = NULL;
 888                struct multicall_space mcs;
 889
 890                /*
 891                 * Do the converse to pin_page.  If we're using split
 892                 * pte locks, we must be holding the lock for while
 893                 * the pte page is unpinned but still RO to prevent
 894                 * concurrent updates from seeing it in this
 895                 * partially-pinned state.
 896                 */
 897                if (level == PT_PTE) {
 898                        ptl = xen_pte_lock(page, mm);
 899
 900                        if (ptl)
 901                                xen_do_pin(MMUEXT_UNPIN_TABLE, pfn);
 902                }
 903
 904                mcs = __xen_mc_entry(0);
 905
 906                MULTI_update_va_mapping(mcs.mc, (unsigned long)pt,
 907                                        pfn_pte(pfn, PAGE_KERNEL),
 908                                        level == PT_PGD ? UVMF_TLB_FLUSH : 0);
 909
 910                if (ptl) {
 911                        /* unlock when batch completed */
 912                        xen_mc_callback(xen_pte_unlock, ptl);
 913                }
 914        }
 915
 916        return 0;               /* never need to flush on unpin */
 917}
 918
 919/* Release a pagetables pages back as normal RW */
 920static void __xen_pgd_unpin(struct mm_struct *mm, pgd_t *pgd)
 921{
 922        trace_xen_mmu_pgd_unpin(mm, pgd);
 923
 924        xen_mc_batch();
 925
 926        xen_do_pin(MMUEXT_UNPIN_TABLE, PFN_DOWN(__pa(pgd)));
 927
 928#ifdef CONFIG_X86_64
 929        {
 930                pgd_t *user_pgd = xen_get_user_pgd(pgd);
 931
 932                if (user_pgd) {
 933                        xen_do_pin(MMUEXT_UNPIN_TABLE,
 934                                   PFN_DOWN(__pa(user_pgd)));
 935                        xen_unpin_page(mm, virt_to_page(user_pgd), PT_PGD);
 936                }
 937        }
 938#endif
 939
 940#ifdef CONFIG_X86_PAE
 941        /* Need to make sure unshared kernel PMD is unpinned */
 942        xen_unpin_page(mm, pgd_page(pgd[pgd_index(TASK_SIZE)]),
 943                       PT_PMD);
 944#endif
 945
 946        __xen_pgd_walk(mm, pgd, xen_unpin_page, USER_LIMIT);
 947
 948        xen_mc_issue(0);
 949}
 950
 951static void xen_pgd_unpin(struct mm_struct *mm)
 952{
 953        __xen_pgd_unpin(mm, mm->pgd);
 954}
 955
 956/*
 957 * On resume, undo any pinning done at save, so that the rest of the
 958 * kernel doesn't see any unexpected pinned pagetables.
 959 */
 960void xen_mm_unpin_all(void)
 961{
 962        struct page *page;
 963
 964        spin_lock(&pgd_lock);
 965
 966        list_for_each_entry(page, &pgd_list, lru) {
 967                if (PageSavePinned(page)) {
 968                        BUG_ON(!PagePinned(page));
 969                        __xen_pgd_unpin(&init_mm, (pgd_t *)page_address(page));
 970                        ClearPageSavePinned(page);
 971                }
 972        }
 973
 974        spin_unlock(&pgd_lock);
 975}
 976
 977static void xen_activate_mm(struct mm_struct *prev, struct mm_struct *next)
 978{
 979        spin_lock(&next->page_table_lock);
 980        xen_pgd_pin(next);
 981        spin_unlock(&next->page_table_lock);
 982}
 983
 984static void xen_dup_mmap(struct mm_struct *oldmm, struct mm_struct *mm)
 985{
 986        spin_lock(&mm->page_table_lock);
 987        xen_pgd_pin(mm);
 988        spin_unlock(&mm->page_table_lock);
 989}
 990
 991static void drop_mm_ref_this_cpu(void *info)
 992{
 993        struct mm_struct *mm = info;
 994
 995        if (this_cpu_read(cpu_tlbstate.loaded_mm) == mm)
 996                leave_mm(smp_processor_id());
 997
 998        /*
 999         * If this cpu still has a stale cr3 reference, then make sure
1000         * it has been flushed.
1001         */
1002        if (this_cpu_read(xen_current_cr3) == __pa(mm->pgd))
1003                xen_mc_flush();
1004}
1005
1006#ifdef CONFIG_SMP
1007/*
1008 * Another cpu may still have their %cr3 pointing at the pagetable, so
1009 * we need to repoint it somewhere else before we can unpin it.
1010 */
1011static void xen_drop_mm_ref(struct mm_struct *mm)
1012{
1013        cpumask_var_t mask;
1014        unsigned cpu;
1015
1016        drop_mm_ref_this_cpu(mm);
1017
1018        /* Get the "official" set of cpus referring to our pagetable. */
1019        if (!alloc_cpumask_var(&mask, GFP_ATOMIC)) {
1020                for_each_online_cpu(cpu) {
1021                        if (per_cpu(xen_current_cr3, cpu) != __pa(mm->pgd))
1022                                continue;
1023                        smp_call_function_single(cpu, drop_mm_ref_this_cpu, mm, 1);
1024                }
1025                return;
1026        }
1027
1028        /*
1029         * It's possible that a vcpu may have a stale reference to our
1030         * cr3, because its in lazy mode, and it hasn't yet flushed
1031         * its set of pending hypercalls yet.  In this case, we can
1032         * look at its actual current cr3 value, and force it to flush
1033         * if needed.
1034         */
1035        cpumask_clear(mask);
1036        for_each_online_cpu(cpu) {
1037                if (per_cpu(xen_current_cr3, cpu) == __pa(mm->pgd))
1038                        cpumask_set_cpu(cpu, mask);
1039        }
1040
1041        smp_call_function_many(mask, drop_mm_ref_this_cpu, mm, 1);
1042        free_cpumask_var(mask);
1043}
1044#else
1045static void xen_drop_mm_ref(struct mm_struct *mm)
1046{
1047        drop_mm_ref_this_cpu(mm);
1048}
1049#endif
1050
1051/*
1052 * While a process runs, Xen pins its pagetables, which means that the
1053 * hypervisor forces it to be read-only, and it controls all updates
1054 * to it.  This means that all pagetable updates have to go via the
1055 * hypervisor, which is moderately expensive.
1056 *
1057 * Since we're pulling the pagetable down, we switch to use init_mm,
1058 * unpin old process pagetable and mark it all read-write, which
1059 * allows further operations on it to be simple memory accesses.
1060 *
1061 * The only subtle point is that another CPU may be still using the
1062 * pagetable because of lazy tlb flushing.  This means we need need to
1063 * switch all CPUs off this pagetable before we can unpin it.
1064 */
1065static void xen_exit_mmap(struct mm_struct *mm)
1066{
1067        get_cpu();              /* make sure we don't move around */
1068        xen_drop_mm_ref(mm);
1069        put_cpu();
1070
1071        spin_lock(&mm->page_table_lock);
1072
1073        /* pgd may not be pinned in the error exit path of execve */
1074        if (xen_page_pinned(mm->pgd))
1075                xen_pgd_unpin(mm);
1076
1077        spin_unlock(&mm->page_table_lock);
1078}
1079
1080static void xen_post_allocator_init(void);
1081
1082static void __init pin_pagetable_pfn(unsigned cmd, unsigned long pfn)
1083{
1084        struct mmuext_op op;
1085
1086        op.cmd = cmd;
1087        op.arg1.mfn = pfn_to_mfn(pfn);
1088        if (HYPERVISOR_mmuext_op(&op, 1, NULL, DOMID_SELF))
1089                BUG();
1090}
1091
1092#ifdef CONFIG_X86_64
1093static void __init xen_cleanhighmap(unsigned long vaddr,
1094                                    unsigned long vaddr_end)
1095{
1096        unsigned long kernel_end = roundup((unsigned long)_brk_end, PMD_SIZE) - 1;
1097        pmd_t *pmd = level2_kernel_pgt + pmd_index(vaddr);
1098
1099        /* NOTE: The loop is more greedy than the cleanup_highmap variant.
1100         * We include the PMD passed in on _both_ boundaries. */
1101        for (; vaddr <= vaddr_end && (pmd < (level2_kernel_pgt + PTRS_PER_PMD));
1102                        pmd++, vaddr += PMD_SIZE) {
1103                if (pmd_none(*pmd))
1104                        continue;
1105                if (vaddr < (unsigned long) _text || vaddr > kernel_end)
1106                        set_pmd(pmd, __pmd(0));
1107        }
1108        /* In case we did something silly, we should crash in this function
1109         * instead of somewhere later and be confusing. */
1110        xen_mc_flush();
1111}
1112
1113/*
1114 * Make a page range writeable and free it.
1115 */
1116static void __init xen_free_ro_pages(unsigned long paddr, unsigned long size)
1117{
1118        void *vaddr = __va(paddr);
1119        void *vaddr_end = vaddr + size;
1120
1121        for (; vaddr < vaddr_end; vaddr += PAGE_SIZE)
1122                make_lowmem_page_readwrite(vaddr);
1123
1124        memblock_free(paddr, size);
1125}
1126
1127static void __init xen_cleanmfnmap_free_pgtbl(void *pgtbl, bool unpin)
1128{
1129        unsigned long pa = __pa(pgtbl) & PHYSICAL_PAGE_MASK;
1130
1131        if (unpin)
1132                pin_pagetable_pfn(MMUEXT_UNPIN_TABLE, PFN_DOWN(pa));
1133        ClearPagePinned(virt_to_page(__va(pa)));
1134        xen_free_ro_pages(pa, PAGE_SIZE);
1135}
1136
1137static void __init xen_cleanmfnmap_pmd(pmd_t *pmd, bool unpin)
1138{
1139        unsigned long pa;
1140        pte_t *pte_tbl;
1141        int i;
1142
1143        if (pmd_large(*pmd)) {
1144                pa = pmd_val(*pmd) & PHYSICAL_PAGE_MASK;
1145                xen_free_ro_pages(pa, PMD_SIZE);
1146                return;
1147        }
1148
1149        pte_tbl = pte_offset_kernel(pmd, 0);
1150        for (i = 0; i < PTRS_PER_PTE; i++) {
1151                if (pte_none(pte_tbl[i]))
1152                        continue;
1153                pa = pte_pfn(pte_tbl[i]) << PAGE_SHIFT;
1154                xen_free_ro_pages(pa, PAGE_SIZE);
1155        }
1156        set_pmd(pmd, __pmd(0));
1157        xen_cleanmfnmap_free_pgtbl(pte_tbl, unpin);
1158}
1159
1160static void __init xen_cleanmfnmap_pud(pud_t *pud, bool unpin)
1161{
1162        unsigned long pa;
1163        pmd_t *pmd_tbl;
1164        int i;
1165
1166        if (pud_large(*pud)) {
1167                pa = pud_val(*pud) & PHYSICAL_PAGE_MASK;
1168                xen_free_ro_pages(pa, PUD_SIZE);
1169                return;
1170        }
1171
1172        pmd_tbl = pmd_offset(pud, 0);
1173        for (i = 0; i < PTRS_PER_PMD; i++) {
1174                if (pmd_none(pmd_tbl[i]))
1175                        continue;
1176                xen_cleanmfnmap_pmd(pmd_tbl + i, unpin);
1177        }
1178        set_pud(pud, __pud(0));
1179        xen_cleanmfnmap_free_pgtbl(pmd_tbl, unpin);
1180}
1181
1182static void __init xen_cleanmfnmap_p4d(p4d_t *p4d, bool unpin)
1183{
1184        unsigned long pa;
1185        pud_t *pud_tbl;
1186        int i;
1187
1188        if (p4d_large(*p4d)) {
1189                pa = p4d_val(*p4d) & PHYSICAL_PAGE_MASK;
1190                xen_free_ro_pages(pa, P4D_SIZE);
1191                return;
1192        }
1193
1194        pud_tbl = pud_offset(p4d, 0);
1195        for (i = 0; i < PTRS_PER_PUD; i++) {
1196                if (pud_none(pud_tbl[i]))
1197                        continue;
1198                xen_cleanmfnmap_pud(pud_tbl + i, unpin);
1199        }
1200        set_p4d(p4d, __p4d(0));
1201        xen_cleanmfnmap_free_pgtbl(pud_tbl, unpin);
1202}
1203
1204/*
1205 * Since it is well isolated we can (and since it is perhaps large we should)
1206 * also free the page tables mapping the initial P->M table.
1207 */
1208static void __init xen_cleanmfnmap(unsigned long vaddr)
1209{
1210        pgd_t *pgd;
1211        p4d_t *p4d;
1212        bool unpin;
1213
1214        unpin = (vaddr == 2 * PGDIR_SIZE);
1215        vaddr &= PMD_MASK;
1216        pgd = pgd_offset_k(vaddr);
1217        p4d = p4d_offset(pgd, 0);
1218        if (!p4d_none(*p4d))
1219                xen_cleanmfnmap_p4d(p4d, unpin);
1220}
1221
1222static void __init xen_pagetable_p2m_free(void)
1223{
1224        unsigned long size;
1225        unsigned long addr;
1226
1227        size = PAGE_ALIGN(xen_start_info->nr_pages * sizeof(unsigned long));
1228
1229        /* No memory or already called. */
1230        if ((unsigned long)xen_p2m_addr == xen_start_info->mfn_list)
1231                return;
1232
1233        /* using __ka address and sticking INVALID_P2M_ENTRY! */
1234        memset((void *)xen_start_info->mfn_list, 0xff, size);
1235
1236        addr = xen_start_info->mfn_list;
1237        /*
1238         * We could be in __ka space.
1239         * We roundup to the PMD, which means that if anybody at this stage is
1240         * using the __ka address of xen_start_info or
1241         * xen_start_info->shared_info they are in going to crash. Fortunatly
1242         * we have already revectored in xen_setup_kernel_pagetable.
1243         */
1244        size = roundup(size, PMD_SIZE);
1245
1246        if (addr >= __START_KERNEL_map) {
1247                xen_cleanhighmap(addr, addr + size);
1248                size = PAGE_ALIGN(xen_start_info->nr_pages *
1249                                  sizeof(unsigned long));
1250                memblock_free(__pa(addr), size);
1251        } else {
1252                xen_cleanmfnmap(addr);
1253        }
1254}
1255
1256static void __init xen_pagetable_cleanhighmap(void)
1257{
1258        unsigned long size;
1259        unsigned long addr;
1260
1261        /* At this stage, cleanup_highmap has already cleaned __ka space
1262         * from _brk_limit way up to the max_pfn_mapped (which is the end of
1263         * the ramdisk). We continue on, erasing PMD entries that point to page
1264         * tables - do note that they are accessible at this stage via __va.
1265         * As Xen is aligning the memory end to a 4MB boundary, for good
1266         * measure we also round up to PMD_SIZE * 2 - which means that if
1267         * anybody is using __ka address to the initial boot-stack - and try
1268         * to use it - they are going to crash. The xen_start_info has been
1269         * taken care of already in xen_setup_kernel_pagetable. */
1270        addr = xen_start_info->pt_base;
1271        size = xen_start_info->nr_pt_frames * PAGE_SIZE;
1272
1273        xen_cleanhighmap(addr, roundup(addr + size, PMD_SIZE * 2));
1274        xen_start_info->pt_base = (unsigned long)__va(__pa(xen_start_info->pt_base));
1275}
1276#endif
1277
1278static void __init xen_pagetable_p2m_setup(void)
1279{
1280        xen_vmalloc_p2m_tree();
1281
1282#ifdef CONFIG_X86_64
1283        xen_pagetable_p2m_free();
1284
1285        xen_pagetable_cleanhighmap();
1286#endif
1287        /* And revector! Bye bye old array */
1288        xen_start_info->mfn_list = (unsigned long)xen_p2m_addr;
1289}
1290
1291static void __init xen_pagetable_init(void)
1292{
1293        paging_init();
1294        xen_post_allocator_init();
1295
1296        xen_pagetable_p2m_setup();
1297
1298        /* Allocate and initialize top and mid mfn levels for p2m structure */
1299        xen_build_mfn_list_list();
1300
1301        /* Remap memory freed due to conflicts with E820 map */
1302        xen_remap_memory();
1303        xen_setup_mfn_list_list();
1304}
1305static void xen_write_cr2(unsigned long cr2)
1306{
1307        this_cpu_read(xen_vcpu)->arch.cr2 = cr2;
1308}
1309
1310static noinline void xen_flush_tlb(void)
1311{
1312        struct mmuext_op *op;
1313        struct multicall_space mcs;
1314
1315        preempt_disable();
1316
1317        mcs = xen_mc_entry(sizeof(*op));
1318
1319        op = mcs.args;
1320        op->cmd = MMUEXT_TLB_FLUSH_LOCAL;
1321        MULTI_mmuext_op(mcs.mc, op, 1, NULL, DOMID_SELF);
1322
1323        xen_mc_issue(PARAVIRT_LAZY_MMU);
1324
1325        preempt_enable();
1326}
1327
1328static void xen_flush_tlb_one_user(unsigned long addr)
1329{
1330        struct mmuext_op *op;
1331        struct multicall_space mcs;
1332
1333        trace_xen_mmu_flush_tlb_one_user(addr);
1334
1335        preempt_disable();
1336
1337        mcs = xen_mc_entry(sizeof(*op));
1338        op = mcs.args;
1339        op->cmd = MMUEXT_INVLPG_LOCAL;
1340        op->arg1.linear_addr = addr & PAGE_MASK;
1341        MULTI_mmuext_op(mcs.mc, op, 1, NULL, DOMID_SELF);
1342
1343        xen_mc_issue(PARAVIRT_LAZY_MMU);
1344
1345        preempt_enable();
1346}
1347
1348static void xen_flush_tlb_others(const struct cpumask *cpus,
1349                                 const struct flush_tlb_info *info)
1350{
1351        struct {
1352                struct mmuext_op op;
1353                DECLARE_BITMAP(mask, NR_CPUS);
1354        } *args;
1355        struct multicall_space mcs;
1356        const size_t mc_entry_size = sizeof(args->op) +
1357                sizeof(args->mask[0]) * BITS_TO_LONGS(num_possible_cpus());
1358
1359        trace_xen_mmu_flush_tlb_others(cpus, info->mm, info->start, info->end);
1360
1361        if (cpumask_empty(cpus))
1362                return;         /* nothing to do */
1363
1364        mcs = xen_mc_entry(mc_entry_size);
1365        args = mcs.args;
1366        args->op.arg2.vcpumask = to_cpumask(args->mask);
1367
1368        /* Remove us, and any offline CPUS. */
1369        cpumask_and(to_cpumask(args->mask), cpus, cpu_online_mask);
1370        cpumask_clear_cpu(smp_processor_id(), to_cpumask(args->mask));
1371
1372        args->op.cmd = MMUEXT_TLB_FLUSH_MULTI;
1373        if (info->end != TLB_FLUSH_ALL &&
1374            (info->end - info->start) <= PAGE_SIZE) {
1375                args->op.cmd = MMUEXT_INVLPG_MULTI;
1376                args->op.arg1.linear_addr = info->start;
1377        }
1378
1379        MULTI_mmuext_op(mcs.mc, &args->op, 1, NULL, DOMID_SELF);
1380
1381        xen_mc_issue(PARAVIRT_LAZY_MMU);
1382}
1383
1384static unsigned long xen_read_cr3(void)
1385{
1386        return this_cpu_read(xen_cr3);
1387}
1388
1389static void set_current_cr3(void *v)
1390{
1391        this_cpu_write(xen_current_cr3, (unsigned long)v);
1392}
1393
1394static void __xen_write_cr3(bool kernel, unsigned long cr3)
1395{
1396        struct mmuext_op op;
1397        unsigned long mfn;
1398
1399        trace_xen_mmu_write_cr3(kernel, cr3);
1400
1401        if (cr3)
1402                mfn = pfn_to_mfn(PFN_DOWN(cr3));
1403        else
1404                mfn = 0;
1405
1406        WARN_ON(mfn == 0 && kernel);
1407
1408        op.cmd = kernel ? MMUEXT_NEW_BASEPTR : MMUEXT_NEW_USER_BASEPTR;
1409        op.arg1.mfn = mfn;
1410
1411        xen_extend_mmuext_op(&op);
1412
1413        if (kernel) {
1414                this_cpu_write(xen_cr3, cr3);
1415
1416                /* Update xen_current_cr3 once the batch has actually
1417                   been submitted. */
1418                xen_mc_callback(set_current_cr3, (void *)cr3);
1419        }
1420}
1421static void xen_write_cr3(unsigned long cr3)
1422{
1423        BUG_ON(preemptible());
1424
1425        xen_mc_batch();  /* disables interrupts */
1426
1427        /* Update while interrupts are disabled, so its atomic with
1428           respect to ipis */
1429        this_cpu_write(xen_cr3, cr3);
1430
1431        __xen_write_cr3(true, cr3);
1432
1433#ifdef CONFIG_X86_64
1434        {
1435                pgd_t *user_pgd = xen_get_user_pgd(__va(cr3));
1436                if (user_pgd)
1437                        __xen_write_cr3(false, __pa(user_pgd));
1438                else
1439                        __xen_write_cr3(false, 0);
1440        }
1441#endif
1442
1443        xen_mc_issue(PARAVIRT_LAZY_CPU);  /* interrupts restored */
1444}
1445
1446#ifdef CONFIG_X86_64
1447/*
1448 * At the start of the day - when Xen launches a guest, it has already
1449 * built pagetables for the guest. We diligently look over them
1450 * in xen_setup_kernel_pagetable and graft as appropriate them in the
1451 * init_top_pgt and its friends. Then when we are happy we load
1452 * the new init_top_pgt - and continue on.
1453 *
1454 * The generic code starts (start_kernel) and 'init_mem_mapping' sets
1455 * up the rest of the pagetables. When it has completed it loads the cr3.
1456 * N.B. that baremetal would start at 'start_kernel' (and the early
1457 * #PF handler would create bootstrap pagetables) - so we are running
1458 * with the same assumptions as what to do when write_cr3 is executed
1459 * at this point.
1460 *
1461 * Since there are no user-page tables at all, we have two variants
1462 * of xen_write_cr3 - the early bootup (this one), and the late one
1463 * (xen_write_cr3). The reason we have to do that is that in 64-bit
1464 * the Linux kernel and user-space are both in ring 3 while the
1465 * hypervisor is in ring 0.
1466 */
1467static void __init xen_write_cr3_init(unsigned long cr3)
1468{
1469        BUG_ON(preemptible());
1470
1471        xen_mc_batch();  /* disables interrupts */
1472
1473        /* Update while interrupts are disabled, so its atomic with
1474           respect to ipis */
1475        this_cpu_write(xen_cr3, cr3);
1476
1477        __xen_write_cr3(true, cr3);
1478
1479        xen_mc_issue(PARAVIRT_LAZY_CPU);  /* interrupts restored */
1480}
1481#endif
1482
1483static int xen_pgd_alloc(struct mm_struct *mm)
1484{
1485        pgd_t *pgd = mm->pgd;
1486        int ret = 0;
1487
1488        BUG_ON(PagePinned(virt_to_page(pgd)));
1489
1490#ifdef CONFIG_X86_64
1491        {
1492                struct page *page = virt_to_page(pgd);
1493                pgd_t *user_pgd;
1494
1495                BUG_ON(page->private != 0);
1496
1497                ret = -ENOMEM;
1498
1499                user_pgd = (pgd_t *)__get_free_page(GFP_KERNEL | __GFP_ZERO);
1500                page->private = (unsigned long)user_pgd;
1501
1502                if (user_pgd != NULL) {
1503#ifdef CONFIG_X86_VSYSCALL_EMULATION
1504                        user_pgd[pgd_index(VSYSCALL_ADDR)] =
1505                                __pgd(__pa(level3_user_vsyscall) | _PAGE_TABLE);
1506#endif
1507                        ret = 0;
1508                }
1509
1510                BUG_ON(PagePinned(virt_to_page(xen_get_user_pgd(pgd))));
1511        }
1512#endif
1513        return ret;
1514}
1515
1516static void xen_pgd_free(struct mm_struct *mm, pgd_t *pgd)
1517{
1518#ifdef CONFIG_X86_64
1519        pgd_t *user_pgd = xen_get_user_pgd(pgd);
1520
1521        if (user_pgd)
1522                free_page((unsigned long)user_pgd);
1523#endif
1524}
1525
1526/*
1527 * Init-time set_pte while constructing initial pagetables, which
1528 * doesn't allow RO page table pages to be remapped RW.
1529 *
1530 * If there is no MFN for this PFN then this page is initially
1531 * ballooned out so clear the PTE (as in decrease_reservation() in
1532 * drivers/xen/balloon.c).
1533 *
1534 * Many of these PTE updates are done on unpinned and writable pages
1535 * and doing a hypercall for these is unnecessary and expensive.  At
1536 * this point it is not possible to tell if a page is pinned or not,
1537 * so always write the PTE directly and rely on Xen trapping and
1538 * emulating any updates as necessary.
1539 */
1540__visible pte_t xen_make_pte_init(pteval_t pte)
1541{
1542#ifdef CONFIG_X86_64
1543        unsigned long pfn;
1544
1545        /*
1546         * Pages belonging to the initial p2m list mapped outside the default
1547         * address range must be mapped read-only. This region contains the
1548         * page tables for mapping the p2m list, too, and page tables MUST be
1549         * mapped read-only.
1550         */
1551        pfn = (pte & PTE_PFN_MASK) >> PAGE_SHIFT;
1552        if (xen_start_info->mfn_list < __START_KERNEL_map &&
1553            pfn >= xen_start_info->first_p2m_pfn &&
1554            pfn < xen_start_info->first_p2m_pfn + xen_start_info->nr_p2m_frames)
1555                pte &= ~_PAGE_RW;
1556#endif
1557        pte = pte_pfn_to_mfn(pte);
1558        return native_make_pte(pte);
1559}
1560PV_CALLEE_SAVE_REGS_THUNK(xen_make_pte_init);
1561
1562static void __init xen_set_pte_init(pte_t *ptep, pte_t pte)
1563{
1564#ifdef CONFIG_X86_32
1565        /* If there's an existing pte, then don't allow _PAGE_RW to be set */
1566        if (pte_mfn(pte) != INVALID_P2M_ENTRY
1567            && pte_val_ma(*ptep) & _PAGE_PRESENT)
1568                pte = __pte_ma(((pte_val_ma(*ptep) & _PAGE_RW) | ~_PAGE_RW) &
1569                               pte_val_ma(pte));
1570#endif
1571        __xen_set_pte(ptep, pte);
1572}
1573
1574/* Early in boot, while setting up the initial pagetable, assume
1575   everything is pinned. */
1576static void __init xen_alloc_pte_init(struct mm_struct *mm, unsigned long pfn)
1577{
1578#ifdef CONFIG_FLATMEM
1579        BUG_ON(mem_map);        /* should only be used early */
1580#endif
1581        make_lowmem_page_readonly(__va(PFN_PHYS(pfn)));
1582        pin_pagetable_pfn(MMUEXT_PIN_L1_TABLE, pfn);
1583}
1584
1585/* Used for pmd and pud */
1586static void __init xen_alloc_pmd_init(struct mm_struct *mm, unsigned long pfn)
1587{
1588#ifdef CONFIG_FLATMEM
1589        BUG_ON(mem_map);        /* should only be used early */
1590#endif
1591        make_lowmem_page_readonly(__va(PFN_PHYS(pfn)));
1592}
1593
1594/* Early release_pte assumes that all pts are pinned, since there's
1595   only init_mm and anything attached to that is pinned. */
1596static void __init xen_release_pte_init(unsigned long pfn)
1597{
1598        pin_pagetable_pfn(MMUEXT_UNPIN_TABLE, pfn);
1599        make_lowmem_page_readwrite(__va(PFN_PHYS(pfn)));
1600}
1601
1602static void __init xen_release_pmd_init(unsigned long pfn)
1603{
1604        make_lowmem_page_readwrite(__va(PFN_PHYS(pfn)));
1605}
1606
1607static inline void __pin_pagetable_pfn(unsigned cmd, unsigned long pfn)
1608{
1609        struct multicall_space mcs;
1610        struct mmuext_op *op;
1611
1612        mcs = __xen_mc_entry(sizeof(*op));
1613        op = mcs.args;
1614        op->cmd = cmd;
1615        op->arg1.mfn = pfn_to_mfn(pfn);
1616
1617        MULTI_mmuext_op(mcs.mc, mcs.args, 1, NULL, DOMID_SELF);
1618}
1619
1620static inline void __set_pfn_prot(unsigned long pfn, pgprot_t prot)
1621{
1622        struct multicall_space mcs;
1623        unsigned long addr = (unsigned long)__va(pfn << PAGE_SHIFT);
1624
1625        mcs = __xen_mc_entry(0);
1626        MULTI_update_va_mapping(mcs.mc, (unsigned long)addr,
1627                                pfn_pte(pfn, prot), 0);
1628}
1629
1630/* This needs to make sure the new pte page is pinned iff its being
1631   attached to a pinned pagetable. */
1632static inline void xen_alloc_ptpage(struct mm_struct *mm, unsigned long pfn,
1633                                    unsigned level)
1634{
1635        bool pinned = xen_page_pinned(mm->pgd);
1636
1637        trace_xen_mmu_alloc_ptpage(mm, pfn, level, pinned);
1638
1639        if (pinned) {
1640                struct page *page = pfn_to_page(pfn);
1641
1642                if (static_branch_likely(&xen_struct_pages_ready))
1643                        SetPagePinned(page);
1644
1645                if (!PageHighMem(page)) {
1646                        xen_mc_batch();
1647
1648                        __set_pfn_prot(pfn, PAGE_KERNEL_RO);
1649
1650                        if (level == PT_PTE && USE_SPLIT_PTE_PTLOCKS)
1651                                __pin_pagetable_pfn(MMUEXT_PIN_L1_TABLE, pfn);
1652
1653                        xen_mc_issue(PARAVIRT_LAZY_MMU);
1654                } else {
1655                        /* make sure there are no stray mappings of
1656                           this page */
1657                        kmap_flush_unused();
1658                }
1659        }
1660}
1661
1662static void xen_alloc_pte(struct mm_struct *mm, unsigned long pfn)
1663{
1664        xen_alloc_ptpage(mm, pfn, PT_PTE);
1665}
1666
1667static void xen_alloc_pmd(struct mm_struct *mm, unsigned long pfn)
1668{
1669        xen_alloc_ptpage(mm, pfn, PT_PMD);
1670}
1671
1672/* This should never happen until we're OK to use struct page */
1673static inline void xen_release_ptpage(unsigned long pfn, unsigned level)
1674{
1675        struct page *page = pfn_to_page(pfn);
1676        bool pinned = PagePinned(page);
1677
1678        trace_xen_mmu_release_ptpage(pfn, level, pinned);
1679
1680        if (pinned) {
1681                if (!PageHighMem(page)) {
1682                        xen_mc_batch();
1683
1684                        if (level == PT_PTE && USE_SPLIT_PTE_PTLOCKS)
1685                                __pin_pagetable_pfn(MMUEXT_UNPIN_TABLE, pfn);
1686
1687                        __set_pfn_prot(pfn, PAGE_KERNEL);
1688
1689                        xen_mc_issue(PARAVIRT_LAZY_MMU);
1690                }
1691                ClearPagePinned(page);
1692        }
1693}
1694
1695static void xen_release_pte(unsigned long pfn)
1696{
1697        xen_release_ptpage(pfn, PT_PTE);
1698}
1699
1700static void xen_release_pmd(unsigned long pfn)
1701{
1702        xen_release_ptpage(pfn, PT_PMD);
1703}
1704
1705#ifdef CONFIG_X86_64
1706static void xen_alloc_pud(struct mm_struct *mm, unsigned long pfn)
1707{
1708        xen_alloc_ptpage(mm, pfn, PT_PUD);
1709}
1710
1711static void xen_release_pud(unsigned long pfn)
1712{
1713        xen_release_ptpage(pfn, PT_PUD);
1714}
1715#endif
1716
1717void __init xen_reserve_top(void)
1718{
1719#ifdef CONFIG_X86_32
1720        unsigned long top = HYPERVISOR_VIRT_START;
1721        struct xen_platform_parameters pp;
1722
1723        if (HYPERVISOR_xen_version(XENVER_platform_parameters, &pp) == 0)
1724                top = pp.virt_start;
1725
1726        reserve_top_address(-top);
1727#endif  /* CONFIG_X86_32 */
1728}
1729
1730/*
1731 * Like __va(), but returns address in the kernel mapping (which is
1732 * all we have until the physical memory mapping has been set up.
1733 */
1734static void * __init __ka(phys_addr_t paddr)
1735{
1736#ifdef CONFIG_X86_64
1737        return (void *)(paddr + __START_KERNEL_map);
1738#else
1739        return __va(paddr);
1740#endif
1741}
1742
1743/* Convert a machine address to physical address */
1744static unsigned long __init m2p(phys_addr_t maddr)
1745{
1746        phys_addr_t paddr;
1747
1748        maddr &= XEN_PTE_MFN_MASK;
1749        paddr = mfn_to_pfn(maddr >> PAGE_SHIFT) << PAGE_SHIFT;
1750
1751        return paddr;
1752}
1753
1754/* Convert a machine address to kernel virtual */
1755static void * __init m2v(phys_addr_t maddr)
1756{
1757        return __ka(m2p(maddr));
1758}
1759
1760/* Set the page permissions on an identity-mapped pages */
1761static void __init set_page_prot_flags(void *addr, pgprot_t prot,
1762                                       unsigned long flags)
1763{
1764        unsigned long pfn = __pa(addr) >> PAGE_SHIFT;
1765        pte_t pte = pfn_pte(pfn, prot);
1766
1767        if (HYPERVISOR_update_va_mapping((unsigned long)addr, pte, flags))
1768                BUG();
1769}
1770static void __init set_page_prot(void *addr, pgprot_t prot)
1771{
1772        return set_page_prot_flags(addr, prot, UVMF_NONE);
1773}
1774#ifdef CONFIG_X86_32
1775static void __init xen_map_identity_early(pmd_t *pmd, unsigned long max_pfn)
1776{
1777        unsigned pmdidx, pteidx;
1778        unsigned ident_pte;
1779        unsigned long pfn;
1780
1781        level1_ident_pgt = extend_brk(sizeof(pte_t) * LEVEL1_IDENT_ENTRIES,
1782                                      PAGE_SIZE);
1783
1784        ident_pte = 0;
1785        pfn = 0;
1786        for (pmdidx = 0; pmdidx < PTRS_PER_PMD && pfn < max_pfn; pmdidx++) {
1787                pte_t *pte_page;
1788
1789                /* Reuse or allocate a page of ptes */
1790                if (pmd_present(pmd[pmdidx]))
1791                        pte_page = m2v(pmd[pmdidx].pmd);
1792                else {
1793                        /* Check for free pte pages */
1794                        if (ident_pte == LEVEL1_IDENT_ENTRIES)
1795                                break;
1796
1797                        pte_page = &level1_ident_pgt[ident_pte];
1798                        ident_pte += PTRS_PER_PTE;
1799
1800                        pmd[pmdidx] = __pmd(__pa(pte_page) | _PAGE_TABLE);
1801                }
1802
1803                /* Install mappings */
1804                for (pteidx = 0; pteidx < PTRS_PER_PTE; pteidx++, pfn++) {
1805                        pte_t pte;
1806
1807                        if (pfn > max_pfn_mapped)
1808                                max_pfn_mapped = pfn;
1809
1810                        if (!pte_none(pte_page[pteidx]))
1811                                continue;
1812
1813                        pte = pfn_pte(pfn, PAGE_KERNEL_EXEC);
1814                        pte_page[pteidx] = pte;
1815                }
1816        }
1817
1818        for (pteidx = 0; pteidx < ident_pte; pteidx += PTRS_PER_PTE)
1819                set_page_prot(&level1_ident_pgt[pteidx], PAGE_KERNEL_RO);
1820
1821        set_page_prot(pmd, PAGE_KERNEL_RO);
1822}
1823#endif
1824void __init xen_setup_machphys_mapping(void)
1825{
1826        struct xen_machphys_mapping mapping;
1827
1828        if (HYPERVISOR_memory_op(XENMEM_machphys_mapping, &mapping) == 0) {
1829                machine_to_phys_mapping = (unsigned long *)mapping.v_start;
1830                machine_to_phys_nr = mapping.max_mfn + 1;
1831        } else {
1832                machine_to_phys_nr = MACH2PHYS_NR_ENTRIES;
1833        }
1834#ifdef CONFIG_X86_32
1835        WARN_ON((machine_to_phys_mapping + (machine_to_phys_nr - 1))
1836                < machine_to_phys_mapping);
1837#endif
1838}
1839
1840#ifdef CONFIG_X86_64
1841static void __init convert_pfn_mfn(void *v)
1842{
1843        pte_t *pte = v;
1844        int i;
1845
1846        /* All levels are converted the same way, so just treat them
1847           as ptes. */
1848        for (i = 0; i < PTRS_PER_PTE; i++)
1849                pte[i] = xen_make_pte(pte[i].pte);
1850}
1851static void __init check_pt_base(unsigned long *pt_base, unsigned long *pt_end,
1852                                 unsigned long addr)
1853{
1854        if (*pt_base == PFN_DOWN(__pa(addr))) {
1855                set_page_prot_flags((void *)addr, PAGE_KERNEL, UVMF_INVLPG);
1856                clear_page((void *)addr);
1857                (*pt_base)++;
1858        }
1859        if (*pt_end == PFN_DOWN(__pa(addr))) {
1860                set_page_prot_flags((void *)addr, PAGE_KERNEL, UVMF_INVLPG);
1861                clear_page((void *)addr);
1862                (*pt_end)--;
1863        }
1864}
1865/*
1866 * Set up the initial kernel pagetable.
1867 *
1868 * We can construct this by grafting the Xen provided pagetable into
1869 * head_64.S's preconstructed pagetables.  We copy the Xen L2's into
1870 * level2_ident_pgt, and level2_kernel_pgt.  This means that only the
1871 * kernel has a physical mapping to start with - but that's enough to
1872 * get __va working.  We need to fill in the rest of the physical
1873 * mapping once some sort of allocator has been set up.
1874 */
1875void __init xen_setup_kernel_pagetable(pgd_t *pgd, unsigned long max_pfn)
1876{
1877        pud_t *l3;
1878        pmd_t *l2;
1879        unsigned long addr[3];
1880        unsigned long pt_base, pt_end;
1881        unsigned i;
1882
1883        /* max_pfn_mapped is the last pfn mapped in the initial memory
1884         * mappings. Considering that on Xen after the kernel mappings we
1885         * have the mappings of some pages that don't exist in pfn space, we
1886         * set max_pfn_mapped to the last real pfn mapped. */
1887        if (xen_start_info->mfn_list < __START_KERNEL_map)
1888                max_pfn_mapped = xen_start_info->first_p2m_pfn;
1889        else
1890                max_pfn_mapped = PFN_DOWN(__pa(xen_start_info->mfn_list));
1891
1892        pt_base = PFN_DOWN(__pa(xen_start_info->pt_base));
1893        pt_end = pt_base + xen_start_info->nr_pt_frames;
1894
1895        /* Zap identity mapping */
1896        init_top_pgt[0] = __pgd(0);
1897
1898        /* Pre-constructed entries are in pfn, so convert to mfn */
1899        /* L4[273] -> level3_ident_pgt  */
1900        /* L4[511] -> level3_kernel_pgt */
1901        convert_pfn_mfn(init_top_pgt);
1902
1903        /* L3_i[0] -> level2_ident_pgt */
1904        convert_pfn_mfn(level3_ident_pgt);
1905        /* L3_k[510] -> level2_kernel_pgt */
1906        /* L3_k[511] -> level2_fixmap_pgt */
1907        convert_pfn_mfn(level3_kernel_pgt);
1908
1909        /* L3_k[511][508-FIXMAP_PMD_NUM ... 507] -> level1_fixmap_pgt */
1910        convert_pfn_mfn(level2_fixmap_pgt);
1911
1912        /* We get [511][511] and have Xen's version of level2_kernel_pgt */
1913        l3 = m2v(pgd[pgd_index(__START_KERNEL_map)].pgd);
1914        l2 = m2v(l3[pud_index(__START_KERNEL_map)].pud);
1915
1916        addr[0] = (unsigned long)pgd;
1917        addr[1] = (unsigned long)l3;
1918        addr[2] = (unsigned long)l2;
1919        /* Graft it onto L4[273][0]. Note that we creating an aliasing problem:
1920         * Both L4[273][0] and L4[511][510] have entries that point to the same
1921         * L2 (PMD) tables. Meaning that if you modify it in __va space
1922         * it will be also modified in the __ka space! (But if you just
1923         * modify the PMD table to point to other PTE's or none, then you
1924         * are OK - which is what cleanup_highmap does) */
1925        copy_page(level2_ident_pgt, l2);
1926        /* Graft it onto L4[511][510] */
1927        copy_page(level2_kernel_pgt, l2);
1928
1929        /*
1930         * Zap execute permission from the ident map. Due to the sharing of
1931         * L1 entries we need to do this in the L2.
1932         */
1933        if (__supported_pte_mask & _PAGE_NX) {
1934                for (i = 0; i < PTRS_PER_PMD; ++i) {
1935                        if (pmd_none(level2_ident_pgt[i]))
1936                                continue;
1937                        level2_ident_pgt[i] = pmd_set_flags(level2_ident_pgt[i], _PAGE_NX);
1938                }
1939        }
1940
1941        /* Copy the initial P->M table mappings if necessary. */
1942        i = pgd_index(xen_start_info->mfn_list);
1943        if (i && i < pgd_index(__START_KERNEL_map))
1944                init_top_pgt[i] = ((pgd_t *)xen_start_info->pt_base)[i];
1945
1946        /* Make pagetable pieces RO */
1947        set_page_prot(init_top_pgt, PAGE_KERNEL_RO);
1948        set_page_prot(level3_ident_pgt, PAGE_KERNEL_RO);
1949        set_page_prot(level3_kernel_pgt, PAGE_KERNEL_RO);
1950        set_page_prot(level3_user_vsyscall, PAGE_KERNEL_RO);
1951        set_page_prot(level2_ident_pgt, PAGE_KERNEL_RO);
1952        set_page_prot(level2_kernel_pgt, PAGE_KERNEL_RO);
1953        set_page_prot(level2_fixmap_pgt, PAGE_KERNEL_RO);
1954
1955        for (i = 0; i < FIXMAP_PMD_NUM; i++) {
1956                set_page_prot(level1_fixmap_pgt + i * PTRS_PER_PTE,
1957                              PAGE_KERNEL_RO);
1958        }
1959
1960        /* Pin down new L4 */
1961        pin_pagetable_pfn(MMUEXT_PIN_L4_TABLE,
1962                          PFN_DOWN(__pa_symbol(init_top_pgt)));
1963
1964        /* Unpin Xen-provided one */
1965        pin_pagetable_pfn(MMUEXT_UNPIN_TABLE, PFN_DOWN(__pa(pgd)));
1966
1967        /*
1968         * At this stage there can be no user pgd, and no page structure to
1969         * attach it to, so make sure we just set kernel pgd.
1970         */
1971        xen_mc_batch();
1972        __xen_write_cr3(true, __pa(init_top_pgt));
1973        xen_mc_issue(PARAVIRT_LAZY_CPU);
1974
1975        /* We can't that easily rip out L3 and L2, as the Xen pagetables are
1976         * set out this way: [L4], [L1], [L2], [L3], [L1], [L1] ...  for
1977         * the initial domain. For guests using the toolstack, they are in:
1978         * [L4], [L3], [L2], [L1], [L1], order .. So for dom0 we can only
1979         * rip out the [L4] (pgd), but for guests we shave off three pages.
1980         */
1981        for (i = 0; i < ARRAY_SIZE(addr); i++)
1982                check_pt_base(&pt_base, &pt_end, addr[i]);
1983
1984        /* Our (by three pages) smaller Xen pagetable that we are using */
1985        xen_pt_base = PFN_PHYS(pt_base);
1986        xen_pt_size = (pt_end - pt_base) * PAGE_SIZE;
1987        memblock_reserve(xen_pt_base, xen_pt_size);
1988
1989        /* Revector the xen_start_info */
1990        xen_start_info = (struct start_info *)__va(__pa(xen_start_info));
1991}
1992
1993/*
1994 * Read a value from a physical address.
1995 */
1996static unsigned long __init xen_read_phys_ulong(phys_addr_t addr)
1997{
1998        unsigned long *vaddr;
1999        unsigned long val;
2000
2001        vaddr = early_memremap_ro(addr, sizeof(val));
2002        val = *vaddr;
2003        early_memunmap(vaddr, sizeof(val));
2004        return val;
2005}
2006
2007/*
2008 * Translate a virtual address to a physical one without relying on mapped
2009 * page tables. Don't rely on big pages being aligned in (guest) physical
2010 * space!
2011 */
2012static phys_addr_t __init xen_early_virt_to_phys(unsigned long vaddr)
2013{
2014        phys_addr_t pa;
2015        pgd_t pgd;
2016        pud_t pud;
2017        pmd_t pmd;
2018        pte_t pte;
2019
2020        pa = read_cr3_pa();
2021        pgd = native_make_pgd(xen_read_phys_ulong(pa + pgd_index(vaddr) *
2022                                                       sizeof(pgd)));
2023        if (!pgd_present(pgd))
2024                return 0;
2025
2026        pa = pgd_val(pgd) & PTE_PFN_MASK;
2027        pud = native_make_pud(xen_read_phys_ulong(pa + pud_index(vaddr) *
2028                                                       sizeof(pud)));
2029        if (!pud_present(pud))
2030                return 0;
2031        pa = pud_val(pud) & PTE_PFN_MASK;
2032        if (pud_large(pud))
2033                return pa + (vaddr & ~PUD_MASK);
2034
2035        pmd = native_make_pmd(xen_read_phys_ulong(pa + pmd_index(vaddr) *
2036                                                       sizeof(pmd)));
2037        if (!pmd_present(pmd))
2038                return 0;
2039        pa = pmd_val(pmd) & PTE_PFN_MASK;
2040        if (pmd_large(pmd))
2041                return pa + (vaddr & ~PMD_MASK);
2042
2043        pte = native_make_pte(xen_read_phys_ulong(pa + pte_index(vaddr) *
2044                                                       sizeof(pte)));
2045        if (!pte_present(pte))
2046                return 0;
2047        pa = pte_pfn(pte) << PAGE_SHIFT;
2048
2049        return pa | (vaddr & ~PAGE_MASK);
2050}
2051
2052/*
2053 * Find a new area for the hypervisor supplied p2m list and relocate the p2m to
2054 * this area.
2055 */
2056void __init xen_relocate_p2m(void)
2057{
2058        phys_addr_t size, new_area, pt_phys, pmd_phys, pud_phys;
2059        unsigned long p2m_pfn, p2m_pfn_end, n_frames, pfn, pfn_end;
2060        int n_pte, n_pt, n_pmd, n_pud, idx_pte, idx_pt, idx_pmd, idx_pud;
2061        pte_t *pt;
2062        pmd_t *pmd;
2063        pud_t *pud;
2064        pgd_t *pgd;
2065        unsigned long *new_p2m;
2066
2067        size = PAGE_ALIGN(xen_start_info->nr_pages * sizeof(unsigned long));
2068        n_pte = roundup(size, PAGE_SIZE) >> PAGE_SHIFT;
2069        n_pt = roundup(size, PMD_SIZE) >> PMD_SHIFT;
2070        n_pmd = roundup(size, PUD_SIZE) >> PUD_SHIFT;
2071        n_pud = roundup(size, P4D_SIZE) >> P4D_SHIFT;
2072        n_frames = n_pte + n_pt + n_pmd + n_pud;
2073
2074        new_area = xen_find_free_area(PFN_PHYS(n_frames));
2075        if (!new_area) {
2076                xen_raw_console_write("Can't find new memory area for p2m needed due to E820 map conflict\n");
2077                BUG();
2078        }
2079
2080        /*
2081         * Setup the page tables for addressing the new p2m list.
2082         * We have asked the hypervisor to map the p2m list at the user address
2083         * PUD_SIZE. It may have done so, or it may have used a kernel space
2084         * address depending on the Xen version.
2085         * To avoid any possible virtual address collision, just use
2086         * 2 * PUD_SIZE for the new area.
2087         */
2088        pud_phys = new_area;
2089        pmd_phys = pud_phys + PFN_PHYS(n_pud);
2090        pt_phys = pmd_phys + PFN_PHYS(n_pmd);
2091        p2m_pfn = PFN_DOWN(pt_phys) + n_pt;
2092
2093        pgd = __va(read_cr3_pa());
2094        new_p2m = (unsigned long *)(2 * PGDIR_SIZE);
2095        for (idx_pud = 0; idx_pud < n_pud; idx_pud++) {
2096                pud = early_memremap(pud_phys, PAGE_SIZE);
2097                clear_page(pud);
2098                for (idx_pmd = 0; idx_pmd < min(n_pmd, PTRS_PER_PUD);
2099                                idx_pmd++) {
2100                        pmd = early_memremap(pmd_phys, PAGE_SIZE);
2101                        clear_page(pmd);
2102                        for (idx_pt = 0; idx_pt < min(n_pt, PTRS_PER_PMD);
2103                                        idx_pt++) {
2104                                pt = early_memremap(pt_phys, PAGE_SIZE);
2105                                clear_page(pt);
2106                                for (idx_pte = 0;
2107                                     idx_pte < min(n_pte, PTRS_PER_PTE);
2108                                     idx_pte++) {
2109                                        pt[idx_pte] = pfn_pte(p2m_pfn,
2110                                                              PAGE_KERNEL);
2111                                        p2m_pfn++;
2112                                }
2113                                n_pte -= PTRS_PER_PTE;
2114                                early_memunmap(pt, PAGE_SIZE);
2115                                make_lowmem_page_readonly(__va(pt_phys));
2116                                pin_pagetable_pfn(MMUEXT_PIN_L1_TABLE,
2117                                                PFN_DOWN(pt_phys));
2118                                pmd[idx_pt] = __pmd(_PAGE_TABLE | pt_phys);
2119                                pt_phys += PAGE_SIZE;
2120                        }
2121                        n_pt -= PTRS_PER_PMD;
2122                        early_memunmap(pmd, PAGE_SIZE);
2123                        make_lowmem_page_readonly(__va(pmd_phys));
2124                        pin_pagetable_pfn(MMUEXT_PIN_L2_TABLE,
2125                                        PFN_DOWN(pmd_phys));
2126                        pud[idx_pmd] = __pud(_PAGE_TABLE | pmd_phys);
2127                        pmd_phys += PAGE_SIZE;
2128                }
2129                n_pmd -= PTRS_PER_PUD;
2130                early_memunmap(pud, PAGE_SIZE);
2131                make_lowmem_page_readonly(__va(pud_phys));
2132                pin_pagetable_pfn(MMUEXT_PIN_L3_TABLE, PFN_DOWN(pud_phys));
2133                set_pgd(pgd + 2 + idx_pud, __pgd(_PAGE_TABLE | pud_phys));
2134                pud_phys += PAGE_SIZE;
2135        }
2136
2137        /* Now copy the old p2m info to the new area. */
2138        memcpy(new_p2m, xen_p2m_addr, size);
2139        xen_p2m_addr = new_p2m;
2140
2141        /* Release the old p2m list and set new list info. */
2142        p2m_pfn = PFN_DOWN(xen_early_virt_to_phys(xen_start_info->mfn_list));
2143        BUG_ON(!p2m_pfn);
2144        p2m_pfn_end = p2m_pfn + PFN_DOWN(size);
2145
2146        if (xen_start_info->mfn_list < __START_KERNEL_map) {
2147                pfn = xen_start_info->first_p2m_pfn;
2148                pfn_end = xen_start_info->first_p2m_pfn +
2149                          xen_start_info->nr_p2m_frames;
2150                set_pgd(pgd + 1, __pgd(0));
2151        } else {
2152                pfn = p2m_pfn;
2153                pfn_end = p2m_pfn_end;
2154        }
2155
2156        memblock_free(PFN_PHYS(pfn), PAGE_SIZE * (pfn_end - pfn));
2157        while (pfn < pfn_end) {
2158                if (pfn == p2m_pfn) {
2159                        pfn = p2m_pfn_end;
2160                        continue;
2161                }
2162                make_lowmem_page_readwrite(__va(PFN_PHYS(pfn)));
2163                pfn++;
2164        }
2165
2166        xen_start_info->mfn_list = (unsigned long)xen_p2m_addr;
2167        xen_start_info->first_p2m_pfn =  PFN_DOWN(new_area);
2168        xen_start_info->nr_p2m_frames = n_frames;
2169}
2170
2171#else   /* !CONFIG_X86_64 */
2172static RESERVE_BRK_ARRAY(pmd_t, initial_kernel_pmd, PTRS_PER_PMD);
2173static RESERVE_BRK_ARRAY(pmd_t, swapper_kernel_pmd, PTRS_PER_PMD);
2174RESERVE_BRK(fixup_kernel_pmd, PAGE_SIZE);
2175RESERVE_BRK(fixup_kernel_pte, PAGE_SIZE);
2176
2177static void __init xen_write_cr3_init(unsigned long cr3)
2178{
2179        unsigned long pfn = PFN_DOWN(__pa(swapper_pg_dir));
2180
2181        BUG_ON(read_cr3_pa() != __pa(initial_page_table));
2182        BUG_ON(cr3 != __pa(swapper_pg_dir));
2183
2184        /*
2185         * We are switching to swapper_pg_dir for the first time (from
2186         * initial_page_table) and therefore need to mark that page
2187         * read-only and then pin it.
2188         *
2189         * Xen disallows sharing of kernel PMDs for PAE
2190         * guests. Therefore we must copy the kernel PMD from
2191         * initial_page_table into a new kernel PMD to be used in
2192         * swapper_pg_dir.
2193         */
2194        swapper_kernel_pmd =
2195                extend_brk(sizeof(pmd_t) * PTRS_PER_PMD, PAGE_SIZE);
2196        copy_page(swapper_kernel_pmd, initial_kernel_pmd);
2197        swapper_pg_dir[KERNEL_PGD_BOUNDARY] =
2198                __pgd(__pa(swapper_kernel_pmd) | _PAGE_PRESENT);
2199        set_page_prot(swapper_kernel_pmd, PAGE_KERNEL_RO);
2200
2201        set_page_prot(swapper_pg_dir, PAGE_KERNEL_RO);
2202        xen_write_cr3(cr3);
2203        pin_pagetable_pfn(MMUEXT_PIN_L3_TABLE, pfn);
2204
2205        pin_pagetable_pfn(MMUEXT_UNPIN_TABLE,
2206                          PFN_DOWN(__pa(initial_page_table)));
2207        set_page_prot(initial_page_table, PAGE_KERNEL);
2208        set_page_prot(initial_kernel_pmd, PAGE_KERNEL);
2209
2210        pv_ops.mmu.write_cr3 = &xen_write_cr3;
2211}
2212
2213/*
2214 * For 32 bit domains xen_start_info->pt_base is the pgd address which might be
2215 * not the first page table in the page table pool.
2216 * Iterate through the initial page tables to find the real page table base.
2217 */
2218static phys_addr_t __init xen_find_pt_base(pmd_t *pmd)
2219{
2220        phys_addr_t pt_base, paddr;
2221        unsigned pmdidx;
2222
2223        pt_base = min(__pa(xen_start_info->pt_base), __pa(pmd));
2224
2225        for (pmdidx = 0; pmdidx < PTRS_PER_PMD; pmdidx++)
2226                if (pmd_present(pmd[pmdidx]) && !pmd_large(pmd[pmdidx])) {
2227                        paddr = m2p(pmd[pmdidx].pmd);
2228                        pt_base = min(pt_base, paddr);
2229                }
2230
2231        return pt_base;
2232}
2233
2234void __init xen_setup_kernel_pagetable(pgd_t *pgd, unsigned long max_pfn)
2235{
2236        pmd_t *kernel_pmd;
2237
2238        kernel_pmd = m2v(pgd[KERNEL_PGD_BOUNDARY].pgd);
2239
2240        xen_pt_base = xen_find_pt_base(kernel_pmd);
2241        xen_pt_size = xen_start_info->nr_pt_frames * PAGE_SIZE;
2242
2243        initial_kernel_pmd =
2244                extend_brk(sizeof(pmd_t) * PTRS_PER_PMD, PAGE_SIZE);
2245
2246        max_pfn_mapped = PFN_DOWN(xen_pt_base + xen_pt_size + 512 * 1024);
2247
2248        copy_page(initial_kernel_pmd, kernel_pmd);
2249
2250        xen_map_identity_early(initial_kernel_pmd, max_pfn);
2251
2252        copy_page(initial_page_table, pgd);
2253        initial_page_table[KERNEL_PGD_BOUNDARY] =
2254                __pgd(__pa(initial_kernel_pmd) | _PAGE_PRESENT);
2255
2256        set_page_prot(initial_kernel_pmd, PAGE_KERNEL_RO);
2257        set_page_prot(initial_page_table, PAGE_KERNEL_RO);
2258        set_page_prot(empty_zero_page, PAGE_KERNEL_RO);
2259
2260        pin_pagetable_pfn(MMUEXT_UNPIN_TABLE, PFN_DOWN(__pa(pgd)));
2261
2262        pin_pagetable_pfn(MMUEXT_PIN_L3_TABLE,
2263                          PFN_DOWN(__pa(initial_page_table)));
2264        xen_write_cr3(__pa(initial_page_table));
2265
2266        memblock_reserve(xen_pt_base, xen_pt_size);
2267}
2268#endif  /* CONFIG_X86_64 */
2269
2270void __init xen_reserve_special_pages(void)
2271{
2272        phys_addr_t paddr;
2273
2274        memblock_reserve(__pa(xen_start_info), PAGE_SIZE);
2275        if (xen_start_info->store_mfn) {
2276                paddr = PFN_PHYS(mfn_to_pfn(xen_start_info->store_mfn));
2277                memblock_reserve(paddr, PAGE_SIZE);
2278        }
2279        if (!xen_initial_domain()) {
2280                paddr = PFN_PHYS(mfn_to_pfn(xen_start_info->console.domU.mfn));
2281                memblock_reserve(paddr, PAGE_SIZE);
2282        }
2283}
2284
2285void __init xen_pt_check_e820(void)
2286{
2287        if (xen_is_e820_reserved(xen_pt_base, xen_pt_size)) {
2288                xen_raw_console_write("Xen hypervisor allocated page table memory conflicts with E820 map\n");
2289                BUG();
2290        }
2291}
2292
2293static unsigned char dummy_mapping[PAGE_SIZE] __page_aligned_bss;
2294
2295static void xen_set_fixmap(unsigned idx, phys_addr_t phys, pgprot_t prot)
2296{
2297        pte_t pte;
2298
2299        phys >>= PAGE_SHIFT;
2300
2301        switch (idx) {
2302        case FIX_BTMAP_END ... FIX_BTMAP_BEGIN:
2303#ifdef CONFIG_X86_32
2304        case FIX_WP_TEST:
2305# ifdef CONFIG_HIGHMEM
2306        case FIX_KMAP_BEGIN ... FIX_KMAP_END:
2307# endif
2308#elif defined(CONFIG_X86_VSYSCALL_EMULATION)
2309        case VSYSCALL_PAGE:
2310#endif
2311                /* All local page mappings */
2312                pte = pfn_pte(phys, prot);
2313                break;
2314
2315#ifdef CONFIG_X86_LOCAL_APIC
2316        case FIX_APIC_BASE:     /* maps dummy local APIC */
2317                pte = pfn_pte(PFN_DOWN(__pa(dummy_mapping)), PAGE_KERNEL);
2318                break;
2319#endif
2320
2321#ifdef CONFIG_X86_IO_APIC
2322        case FIX_IO_APIC_BASE_0 ... FIX_IO_APIC_BASE_END:
2323                /*
2324                 * We just don't map the IO APIC - all access is via
2325                 * hypercalls.  Keep the address in the pte for reference.
2326                 */
2327                pte = pfn_pte(PFN_DOWN(__pa(dummy_mapping)), PAGE_KERNEL);
2328                break;
2329#endif
2330
2331        case FIX_PARAVIRT_BOOTMAP:
2332                /* This is an MFN, but it isn't an IO mapping from the
2333                   IO domain */
2334                pte = mfn_pte(phys, prot);
2335                break;
2336
2337        default:
2338                /* By default, set_fixmap is used for hardware mappings */
2339                pte = mfn_pte(phys, prot);
2340                break;
2341        }
2342
2343        __native_set_fixmap(idx, pte);
2344
2345#ifdef CONFIG_X86_VSYSCALL_EMULATION
2346        /* Replicate changes to map the vsyscall page into the user
2347           pagetable vsyscall mapping. */
2348        if (idx == VSYSCALL_PAGE) {
2349                unsigned long vaddr = __fix_to_virt(idx);
2350                set_pte_vaddr_pud(level3_user_vsyscall, vaddr, pte);
2351        }
2352#endif
2353}
2354
2355static void __init xen_post_allocator_init(void)
2356{
2357        pv_ops.mmu.set_pte = xen_set_pte;
2358        pv_ops.mmu.set_pmd = xen_set_pmd;
2359        pv_ops.mmu.set_pud = xen_set_pud;
2360#ifdef CONFIG_X86_64
2361        pv_ops.mmu.set_p4d = xen_set_p4d;
2362#endif
2363
2364        /* This will work as long as patching hasn't happened yet
2365           (which it hasn't) */
2366        pv_ops.mmu.alloc_pte = xen_alloc_pte;
2367        pv_ops.mmu.alloc_pmd = xen_alloc_pmd;
2368        pv_ops.mmu.release_pte = xen_release_pte;
2369        pv_ops.mmu.release_pmd = xen_release_pmd;
2370#ifdef CONFIG_X86_64
2371        pv_ops.mmu.alloc_pud = xen_alloc_pud;
2372        pv_ops.mmu.release_pud = xen_release_pud;
2373#endif
2374        pv_ops.mmu.make_pte = PV_CALLEE_SAVE(xen_make_pte);
2375
2376#ifdef CONFIG_X86_64
2377        pv_ops.mmu.write_cr3 = &xen_write_cr3;
2378#endif
2379}
2380
2381static void xen_leave_lazy_mmu(void)
2382{
2383        preempt_disable();
2384        xen_mc_flush();
2385        paravirt_leave_lazy_mmu();
2386        preempt_enable();
2387}
2388
2389static const struct pv_mmu_ops xen_mmu_ops __initconst = {
2390        .read_cr2 = __PV_IS_CALLEE_SAVE(xen_read_cr2),
2391        .write_cr2 = xen_write_cr2,
2392
2393        .read_cr3 = xen_read_cr3,
2394        .write_cr3 = xen_write_cr3_init,
2395
2396        .flush_tlb_user = xen_flush_tlb,
2397        .flush_tlb_kernel = xen_flush_tlb,
2398        .flush_tlb_one_user = xen_flush_tlb_one_user,
2399        .flush_tlb_others = xen_flush_tlb_others,
2400        .tlb_remove_table = tlb_remove_table,
2401
2402        .pgd_alloc = xen_pgd_alloc,
2403        .pgd_free = xen_pgd_free,
2404
2405        .alloc_pte = xen_alloc_pte_init,
2406        .release_pte = xen_release_pte_init,
2407        .alloc_pmd = xen_alloc_pmd_init,
2408        .release_pmd = xen_release_pmd_init,
2409
2410        .set_pte = xen_set_pte_init,
2411        .set_pte_at = xen_set_pte_at,
2412        .set_pmd = xen_set_pmd_hyper,
2413
2414        .ptep_modify_prot_start = __ptep_modify_prot_start,
2415        .ptep_modify_prot_commit = __ptep_modify_prot_commit,
2416
2417        .pte_val = PV_CALLEE_SAVE(xen_pte_val),
2418        .pgd_val = PV_CALLEE_SAVE(xen_pgd_val),
2419
2420        .make_pte = PV_CALLEE_SAVE(xen_make_pte_init),
2421        .make_pgd = PV_CALLEE_SAVE(xen_make_pgd),
2422
2423#ifdef CONFIG_X86_PAE
2424        .set_pte_atomic = xen_set_pte_atomic,
2425        .pte_clear = xen_pte_clear,
2426        .pmd_clear = xen_pmd_clear,
2427#endif  /* CONFIG_X86_PAE */
2428        .set_pud = xen_set_pud_hyper,
2429
2430        .make_pmd = PV_CALLEE_SAVE(xen_make_pmd),
2431        .pmd_val = PV_CALLEE_SAVE(xen_pmd_val),
2432
2433#ifdef CONFIG_X86_64
2434        .pud_val = PV_CALLEE_SAVE(xen_pud_val),
2435        .make_pud = PV_CALLEE_SAVE(xen_make_pud),
2436        .set_p4d = xen_set_p4d_hyper,
2437
2438        .alloc_pud = xen_alloc_pmd_init,
2439        .release_pud = xen_release_pmd_init,
2440
2441#if CONFIG_PGTABLE_LEVELS >= 5
2442        .p4d_val = PV_CALLEE_SAVE(xen_p4d_val),
2443        .make_p4d = PV_CALLEE_SAVE(xen_make_p4d),
2444#endif
2445#endif  /* CONFIG_X86_64 */
2446
2447        .activate_mm = xen_activate_mm,
2448        .dup_mmap = xen_dup_mmap,
2449        .exit_mmap = xen_exit_mmap,
2450
2451        .lazy_mode = {
2452                .enter = paravirt_enter_lazy_mmu,
2453                .leave = xen_leave_lazy_mmu,
2454                .flush = paravirt_flush_lazy_mmu,
2455        },
2456
2457        .set_fixmap = xen_set_fixmap,
2458};
2459
2460void __init xen_init_mmu_ops(void)
2461{
2462        x86_init.paging.pagetable_init = xen_pagetable_init;
2463        x86_init.hyper.init_after_bootmem = xen_after_bootmem;
2464
2465        pv_ops.mmu = xen_mmu_ops;
2466
2467        memset(dummy_mapping, 0xff, PAGE_SIZE);
2468}
2469
2470/* Protected by xen_reservation_lock. */
2471#define MAX_CONTIG_ORDER 9 /* 2MB */
2472static unsigned long discontig_frames[1<<MAX_CONTIG_ORDER];
2473
2474#define VOID_PTE (mfn_pte(0, __pgprot(0)))
2475static void xen_zap_pfn_range(unsigned long vaddr, unsigned int order,
2476                                unsigned long *in_frames,
2477                                unsigned long *out_frames)
2478{
2479        int i;
2480        struct multicall_space mcs;
2481
2482        xen_mc_batch();
2483        for (i = 0; i < (1UL<<order); i++, vaddr += PAGE_SIZE) {
2484                mcs = __xen_mc_entry(0);
2485
2486                if (in_frames)
2487                        in_frames[i] = virt_to_mfn(vaddr);
2488
2489                MULTI_update_va_mapping(mcs.mc, vaddr, VOID_PTE, 0);
2490                __set_phys_to_machine(virt_to_pfn(vaddr), INVALID_P2M_ENTRY);
2491
2492                if (out_frames)
2493                        out_frames[i] = virt_to_pfn(vaddr);
2494        }
2495        xen_mc_issue(0);
2496}
2497
2498/*
2499 * Update the pfn-to-mfn mappings for a virtual address range, either to
2500 * point to an array of mfns, or contiguously from a single starting
2501 * mfn.
2502 */
2503static void xen_remap_exchanged_ptes(unsigned long vaddr, int order,
2504                                     unsigned long *mfns,
2505                                     unsigned long first_mfn)
2506{
2507        unsigned i, limit;
2508        unsigned long mfn;
2509
2510        xen_mc_batch();
2511
2512        limit = 1u << order;
2513        for (i = 0; i < limit; i++, vaddr += PAGE_SIZE) {
2514                struct multicall_space mcs;
2515                unsigned flags;
2516
2517                mcs = __xen_mc_entry(0);
2518                if (mfns)
2519                        mfn = mfns[i];
2520                else
2521                        mfn = first_mfn + i;
2522
2523                if (i < (limit - 1))
2524                        flags = 0;
2525                else {
2526                        if (order == 0)
2527                                flags = UVMF_INVLPG | UVMF_ALL;
2528                        else
2529                                flags = UVMF_TLB_FLUSH | UVMF_ALL;
2530                }
2531
2532                MULTI_update_va_mapping(mcs.mc, vaddr,
2533                                mfn_pte(mfn, PAGE_KERNEL), flags);
2534
2535                set_phys_to_machine(virt_to_pfn(vaddr), mfn);
2536        }
2537
2538        xen_mc_issue(0);
2539}
2540
2541/*
2542 * Perform the hypercall to exchange a region of our pfns to point to
2543 * memory with the required contiguous alignment.  Takes the pfns as
2544 * input, and populates mfns as output.
2545 *
2546 * Returns a success code indicating whether the hypervisor was able to
2547 * satisfy the request or not.
2548 */
2549static int xen_exchange_memory(unsigned long extents_in, unsigned int order_in,
2550                               unsigned long *pfns_in,
2551                               unsigned long extents_out,
2552                               unsigned int order_out,
2553                               unsigned long *mfns_out,
2554                               unsigned int address_bits)
2555{
2556        long rc;
2557        int success;
2558
2559        struct xen_memory_exchange exchange = {
2560                .in = {
2561                        .nr_extents   = extents_in,
2562                        .extent_order = order_in,
2563                        .extent_start = pfns_in,
2564                        .domid        = DOMID_SELF
2565                },
2566                .out = {
2567                        .nr_extents   = extents_out,
2568                        .extent_order = order_out,
2569                        .extent_start = mfns_out,
2570                        .address_bits = address_bits,
2571                        .domid        = DOMID_SELF
2572                }
2573        };
2574
2575        BUG_ON(extents_in << order_in != extents_out << order_out);
2576
2577        rc = HYPERVISOR_memory_op(XENMEM_exchange, &exchange);
2578        success = (exchange.nr_exchanged == extents_in);
2579
2580        BUG_ON(!success && ((exchange.nr_exchanged != 0) || (rc == 0)));
2581        BUG_ON(success && (rc != 0));
2582
2583        return success;
2584}
2585
2586int xen_create_contiguous_region(phys_addr_t pstart, unsigned int order,
2587                                 unsigned int address_bits,
2588                                 dma_addr_t *dma_handle)
2589{
2590        unsigned long *in_frames = discontig_frames, out_frame;
2591        unsigned long  flags;
2592        int            success;
2593        unsigned long vstart = (unsigned long)phys_to_virt(pstart);
2594
2595        /*
2596         * Currently an auto-translated guest will not perform I/O, nor will
2597         * it require PAE page directories below 4GB. Therefore any calls to
2598         * this function are redundant and can be ignored.
2599         */
2600
2601        if (unlikely(order > MAX_CONTIG_ORDER))
2602                return -ENOMEM;
2603
2604        memset((void *) vstart, 0, PAGE_SIZE << order);
2605
2606        spin_lock_irqsave(&xen_reservation_lock, flags);
2607
2608        /* 1. Zap current PTEs, remembering MFNs. */
2609        xen_zap_pfn_range(vstart, order, in_frames, NULL);
2610
2611        /* 2. Get a new contiguous memory extent. */
2612        out_frame = virt_to_pfn(vstart);
2613        success = xen_exchange_memory(1UL << order, 0, in_frames,
2614                                      1, order, &out_frame,
2615                                      address_bits);
2616
2617        /* 3. Map the new extent in place of old pages. */
2618        if (success)
2619                xen_remap_exchanged_ptes(vstart, order, NULL, out_frame);
2620        else
2621                xen_remap_exchanged_ptes(vstart, order, in_frames, 0);
2622
2623        spin_unlock_irqrestore(&xen_reservation_lock, flags);
2624
2625        *dma_handle = virt_to_machine(vstart).maddr;
2626        return success ? 0 : -ENOMEM;
2627}
2628
2629void xen_destroy_contiguous_region(phys_addr_t pstart, unsigned int order)
2630{
2631        unsigned long *out_frames = discontig_frames, in_frame;
2632        unsigned long  flags;
2633        int success;
2634        unsigned long vstart;
2635
2636        if (unlikely(order > MAX_CONTIG_ORDER))
2637                return;
2638
2639        vstart = (unsigned long)phys_to_virt(pstart);
2640        memset((void *) vstart, 0, PAGE_SIZE << order);
2641
2642        spin_lock_irqsave(&xen_reservation_lock, flags);
2643
2644        /* 1. Find start MFN of contiguous extent. */
2645        in_frame = virt_to_mfn(vstart);
2646
2647        /* 2. Zap current PTEs. */
2648        xen_zap_pfn_range(vstart, order, NULL, out_frames);
2649
2650        /* 3. Do the exchange for non-contiguous MFNs. */
2651        success = xen_exchange_memory(1, order, &in_frame, 1UL << order,
2652                                        0, out_frames, 0);
2653
2654        /* 4. Map new pages in place of old pages. */
2655        if (success)
2656                xen_remap_exchanged_ptes(vstart, order, out_frames, 0);
2657        else
2658                xen_remap_exchanged_ptes(vstart, order, NULL, in_frame);
2659
2660        spin_unlock_irqrestore(&xen_reservation_lock, flags);
2661}
2662
2663static noinline void xen_flush_tlb_all(void)
2664{
2665        struct mmuext_op *op;
2666        struct multicall_space mcs;
2667
2668        preempt_disable();
2669
2670        mcs = xen_mc_entry(sizeof(*op));
2671
2672        op = mcs.args;
2673        op->cmd = MMUEXT_TLB_FLUSH_ALL;
2674        MULTI_mmuext_op(mcs.mc, op, 1, NULL, DOMID_SELF);
2675
2676        xen_mc_issue(PARAVIRT_LAZY_MMU);
2677
2678        preempt_enable();
2679}
2680
2681#define REMAP_BATCH_SIZE 16
2682
2683struct remap_data {
2684        xen_pfn_t *pfn;
2685        bool contiguous;
2686        bool no_translate;
2687        pgprot_t prot;
2688        struct mmu_update *mmu_update;
2689};
2690
2691static int remap_area_pfn_pte_fn(pte_t *ptep, unsigned long addr, void *data)
2692{
2693        struct remap_data *rmd = data;
2694        pte_t pte = pte_mkspecial(mfn_pte(*rmd->pfn, rmd->prot));
2695
2696        /*
2697         * If we have a contiguous range, just update the pfn itself,
2698         * else update pointer to be "next pfn".
2699         */
2700        if (rmd->contiguous)
2701                (*rmd->pfn)++;
2702        else
2703                rmd->pfn++;
2704
2705        rmd->mmu_update->ptr = virt_to_machine(ptep).maddr;
2706        rmd->mmu_update->ptr |= rmd->no_translate ?
2707                MMU_PT_UPDATE_NO_TRANSLATE :
2708                MMU_NORMAL_PT_UPDATE;
2709        rmd->mmu_update->val = pte_val_ma(pte);
2710        rmd->mmu_update++;
2711
2712        return 0;
2713}
2714
2715int xen_remap_pfn(struct vm_area_struct *vma, unsigned long addr,
2716                  xen_pfn_t *pfn, int nr, int *err_ptr, pgprot_t prot,
2717                  unsigned int domid, bool no_translate, struct page **pages)
2718{
2719        int err = 0;
2720        struct remap_data rmd;
2721        struct mmu_update mmu_update[REMAP_BATCH_SIZE];
2722        unsigned long range;
2723        int mapped = 0;
2724
2725        BUG_ON(!((vma->vm_flags & (VM_PFNMAP | VM_IO)) == (VM_PFNMAP | VM_IO)));
2726
2727        rmd.pfn = pfn;
2728        rmd.prot = prot;
2729        /*
2730         * We use the err_ptr to indicate if there we are doing a contiguous
2731         * mapping or a discontigious mapping.
2732         */
2733        rmd.contiguous = !err_ptr;
2734        rmd.no_translate = no_translate;
2735
2736        while (nr) {
2737                int index = 0;
2738                int done = 0;
2739                int batch = min(REMAP_BATCH_SIZE, nr);
2740                int batch_left = batch;
2741
2742                range = (unsigned long)batch << PAGE_SHIFT;
2743
2744                rmd.mmu_update = mmu_update;
2745                err = apply_to_page_range(vma->vm_mm, addr, range,
2746                                          remap_area_pfn_pte_fn, &rmd);
2747                if (err)
2748                        goto out;
2749
2750                /*
2751                 * We record the error for each page that gives an error, but
2752                 * continue mapping until the whole set is done
2753                 */
2754                do {
2755                        int i;
2756
2757                        err = HYPERVISOR_mmu_update(&mmu_update[index],
2758                                                    batch_left, &done, domid);
2759
2760                        /*
2761                         * @err_ptr may be the same buffer as @gfn, so
2762                         * only clear it after each chunk of @gfn is
2763                         * used.
2764                         */
2765                        if (err_ptr) {
2766                                for (i = index; i < index + done; i++)
2767                                        err_ptr[i] = 0;
2768                        }
2769                        if (err < 0) {
2770                                if (!err_ptr)
2771                                        goto out;
2772                                err_ptr[i] = err;
2773                                done++; /* Skip failed frame. */
2774                        } else
2775                                mapped += done;
2776                        batch_left -= done;
2777                        index += done;
2778                } while (batch_left);
2779
2780                nr -= batch;
2781                addr += range;
2782                if (err_ptr)
2783                        err_ptr += batch;
2784                cond_resched();
2785        }
2786out:
2787
2788        xen_flush_tlb_all();
2789
2790        return err < 0 ? err : mapped;
2791}
2792EXPORT_SYMBOL_GPL(xen_remap_pfn);
2793
2794#ifdef CONFIG_KEXEC_CORE
2795phys_addr_t paddr_vmcoreinfo_note(void)
2796{
2797        if (xen_pv_domain())
2798                return virt_to_machine(vmcoreinfo_note).maddr;
2799        else
2800                return __pa(vmcoreinfo_note);
2801}
2802#endif /* CONFIG_KEXEC_CORE */
2803