qemu/win_dump.c
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   1/*
   2 * Windows crashdump
   3 *
   4 * Copyright (c) 2018 Virtuozzo International GmbH
   5 *
   6 * This work is licensed under the terms of the GNU GPL, version 2 or later.
   7 * See the COPYING file in the top-level directory.
   8 *
   9 */
  10
  11#include "qemu/osdep.h"
  12#include "qemu/cutils.h"
  13#include "elf.h"
  14#include "cpu.h"
  15#include "exec/hwaddr.h"
  16#include "monitor/monitor.h"
  17#include "sysemu/kvm.h"
  18#include "sysemu/dump.h"
  19#include "sysemu/sysemu.h"
  20#include "sysemu/memory_mapping.h"
  21#include "sysemu/cpus.h"
  22#include "qapi/error.h"
  23#include "qapi/qmp/qerror.h"
  24#include "qemu/error-report.h"
  25#include "hw/misc/vmcoreinfo.h"
  26#include "win_dump.h"
  27
  28static size_t write_run(WinDumpPhyMemRun64 *run, int fd, Error **errp)
  29{
  30    void *buf;
  31    uint64_t addr = run->BasePage << TARGET_PAGE_BITS;
  32    uint64_t size = run->PageCount << TARGET_PAGE_BITS;
  33    uint64_t len, l;
  34    size_t total = 0;
  35
  36    while (size) {
  37        len = size;
  38
  39        buf = cpu_physical_memory_map(addr, &len, false);
  40        if (!buf) {
  41            error_setg(errp, "win-dump: failed to map physical range"
  42                             " 0x%016" PRIx64 "-0x%016" PRIx64, addr, addr + size - 1);
  43            return 0;
  44        }
  45
  46        l = qemu_write_full(fd, buf, len);
  47        cpu_physical_memory_unmap(buf, addr, false, len);
  48        if (l != len) {
  49            error_setg(errp, QERR_IO_ERROR);
  50            return 0;
  51        }
  52
  53        addr += l;
  54        size -= l;
  55        total += l;
  56    }
  57
  58    return total;
  59}
  60
  61static void write_runs(DumpState *s, WinDumpHeader64 *h, Error **errp)
  62{
  63    WinDumpPhyMemDesc64 *desc = &h->PhysicalMemoryBlock;
  64    WinDumpPhyMemRun64 *run = desc->Run;
  65    Error *local_err = NULL;
  66    int i;
  67
  68    for (i = 0; i < desc->NumberOfRuns; i++) {
  69        s->written_size += write_run(run + i, s->fd, &local_err);
  70        if (local_err) {
  71            error_propagate(errp, local_err);
  72            return;
  73        }
  74    }
  75}
  76
  77static void patch_mm_pfn_database(WinDumpHeader64 *h, Error **errp)
  78{
  79    if (cpu_memory_rw_debug(first_cpu,
  80            h->KdDebuggerDataBlock + KDBG_MM_PFN_DATABASE_OFFSET64,
  81            (uint8_t *)&h->PfnDatabase, sizeof(h->PfnDatabase), 0)) {
  82        error_setg(errp, "win-dump: failed to read MmPfnDatabase");
  83        return;
  84    }
  85}
  86
  87static void patch_bugcheck_data(WinDumpHeader64 *h, Error **errp)
  88{
  89    uint64_t KiBugcheckData;
  90
  91    if (cpu_memory_rw_debug(first_cpu,
  92            h->KdDebuggerDataBlock + KDBG_KI_BUGCHECK_DATA_OFFSET64,
  93            (uint8_t *)&KiBugcheckData, sizeof(KiBugcheckData), 0)) {
  94        error_setg(errp, "win-dump: failed to read KiBugcheckData");
  95        return;
  96    }
  97
  98    if (cpu_memory_rw_debug(first_cpu,
  99            KiBugcheckData,
 100            h->BugcheckData, sizeof(h->BugcheckData), 0)) {
 101        error_setg(errp, "win-dump: failed to read bugcheck data");
 102        return;
 103    }
 104
 105    /*
 106     * If BugcheckCode wasn't saved, we consider guest OS as alive.
 107     */
 108
 109    if (!h->BugcheckCode) {
 110        h->BugcheckCode = LIVE_SYSTEM_DUMP;
 111    }
 112}
 113
 114/*
 115 * This routine tries to correct mistakes in crashdump header.
 116 */
 117static void patch_header(WinDumpHeader64 *h)
 118{
 119    Error *local_err = NULL;
 120
 121    h->RequiredDumpSpace = sizeof(WinDumpHeader64) +
 122            (h->PhysicalMemoryBlock.NumberOfPages << TARGET_PAGE_BITS);
 123    h->PhysicalMemoryBlock.unused = 0;
 124    h->unused1 = 0;
 125
 126    patch_mm_pfn_database(h, &local_err);
 127    if (local_err) {
 128        warn_report_err(local_err);
 129        local_err = NULL;
 130    }
 131    patch_bugcheck_data(h, &local_err);
 132    if (local_err) {
 133        warn_report_err(local_err);
 134    }
 135}
 136
 137static void check_header(WinDumpHeader64 *h, Error **errp)
 138{
 139    const char Signature[] = "PAGE";
 140    const char ValidDump[] = "DU64";
 141
 142    if (memcmp(h->Signature, Signature, sizeof(h->Signature))) {
 143        error_setg(errp, "win-dump: invalid header, expected '%.4s',"
 144                         " got '%.4s'", Signature, h->Signature);
 145        return;
 146    }
 147
 148    if (memcmp(h->ValidDump, ValidDump, sizeof(h->ValidDump))) {
 149        error_setg(errp, "win-dump: invalid header, expected '%.4s',"
 150                         " got '%.4s'", ValidDump, h->ValidDump);
 151        return;
 152    }
 153}
 154
 155static void check_kdbg(WinDumpHeader64 *h, Error **errp)
 156{
 157    const char OwnerTag[] = "KDBG";
 158    char read_OwnerTag[4];
 159    uint64_t KdDebuggerDataBlock = h->KdDebuggerDataBlock;
 160    bool try_fallback = true;
 161
 162try_again:
 163    if (cpu_memory_rw_debug(first_cpu,
 164            KdDebuggerDataBlock + KDBG_OWNER_TAG_OFFSET64,
 165            (uint8_t *)&read_OwnerTag, sizeof(read_OwnerTag), 0)) {
 166        error_setg(errp, "win-dump: failed to read OwnerTag");
 167        return;
 168    }
 169
 170    if (memcmp(read_OwnerTag, OwnerTag, sizeof(read_OwnerTag))) {
 171        if (try_fallback) {
 172            /*
 173             * If attempt to use original KDBG failed
 174             * (most likely because of its encryption),
 175             * we try to use KDBG obtained by guest driver.
 176             */
 177
 178            KdDebuggerDataBlock = h->BugcheckParameter1;
 179            try_fallback = false;
 180            goto try_again;
 181        } else {
 182            error_setg(errp, "win-dump: invalid KDBG OwnerTag,"
 183                             " expected '%.4s', got '%.4s'",
 184                             OwnerTag, read_OwnerTag);
 185            return;
 186        }
 187    }
 188
 189    h->KdDebuggerDataBlock = KdDebuggerDataBlock;
 190}
 191
 192struct saved_context {
 193    WinContext ctx;
 194    uint64_t addr;
 195};
 196
 197static void patch_and_save_context(WinDumpHeader64 *h,
 198                                   struct saved_context *saved_ctx,
 199                                   Error **errp)
 200{
 201    uint64_t KiProcessorBlock;
 202    uint16_t OffsetPrcbContext;
 203    CPUState *cpu;
 204    int i = 0;
 205
 206    if (cpu_memory_rw_debug(first_cpu,
 207            h->KdDebuggerDataBlock + KDBG_KI_PROCESSOR_BLOCK_OFFSET64,
 208            (uint8_t *)&KiProcessorBlock, sizeof(KiProcessorBlock), 0)) {
 209        error_setg(errp, "win-dump: failed to read KiProcessorBlock");
 210        return;
 211    }
 212
 213    if (cpu_memory_rw_debug(first_cpu,
 214            h->KdDebuggerDataBlock + KDBG_OFFSET_PRCB_CONTEXT_OFFSET64,
 215            (uint8_t *)&OffsetPrcbContext, sizeof(OffsetPrcbContext), 0)) {
 216        error_setg(errp, "win-dump: failed to read OffsetPrcbContext");
 217        return;
 218    }
 219
 220    CPU_FOREACH(cpu) {
 221        X86CPU *x86_cpu = X86_CPU(cpu);
 222        CPUX86State *env = &x86_cpu->env;
 223        uint64_t Prcb;
 224        uint64_t Context;
 225        WinContext ctx;
 226
 227        if (cpu_memory_rw_debug(first_cpu,
 228                KiProcessorBlock + i * sizeof(uint64_t),
 229                (uint8_t *)&Prcb, sizeof(Prcb), 0)) {
 230            error_setg(errp, "win-dump: failed to read"
 231                             " CPU #%d PRCB location", i);
 232            return;
 233        }
 234
 235        if (cpu_memory_rw_debug(first_cpu,
 236                Prcb + OffsetPrcbContext,
 237                (uint8_t *)&Context, sizeof(Context), 0)) {
 238            error_setg(errp, "win-dump: failed to read"
 239                             " CPU #%d ContextFrame location", i);
 240            return;
 241        }
 242
 243        saved_ctx[i].addr = Context;
 244
 245        ctx = (WinContext){
 246            .ContextFlags = WIN_CTX_ALL,
 247            .MxCsr = env->mxcsr,
 248
 249            .SegEs = env->segs[0].selector,
 250            .SegCs = env->segs[1].selector,
 251            .SegSs = env->segs[2].selector,
 252            .SegDs = env->segs[3].selector,
 253            .SegFs = env->segs[4].selector,
 254            .SegGs = env->segs[5].selector,
 255            .EFlags = cpu_compute_eflags(env),
 256
 257            .Dr0 = env->dr[0],
 258            .Dr1 = env->dr[1],
 259            .Dr2 = env->dr[2],
 260            .Dr3 = env->dr[3],
 261            .Dr6 = env->dr[6],
 262            .Dr7 = env->dr[7],
 263
 264            .Rax = env->regs[R_EAX],
 265            .Rbx = env->regs[R_EBX],
 266            .Rcx = env->regs[R_ECX],
 267            .Rdx = env->regs[R_EDX],
 268            .Rsp = env->regs[R_ESP],
 269            .Rbp = env->regs[R_EBP],
 270            .Rsi = env->regs[R_ESI],
 271            .Rdi = env->regs[R_EDI],
 272            .R8  = env->regs[8],
 273            .R9  = env->regs[9],
 274            .R10 = env->regs[10],
 275            .R11 = env->regs[11],
 276            .R12 = env->regs[12],
 277            .R13 = env->regs[13],
 278            .R14 = env->regs[14],
 279            .R15 = env->regs[15],
 280
 281            .Rip = env->eip,
 282            .FltSave = {
 283                .MxCsr = env->mxcsr,
 284            },
 285        };
 286
 287        if (cpu_memory_rw_debug(first_cpu, Context,
 288                (uint8_t *)&saved_ctx[i].ctx, sizeof(WinContext), 0)) {
 289            error_setg(errp, "win-dump: failed to save CPU #%d context", i);
 290            return;
 291        }
 292
 293        if (cpu_memory_rw_debug(first_cpu, Context,
 294                (uint8_t *)&ctx, sizeof(WinContext), 1)) {
 295            error_setg(errp, "win-dump: failed to write CPU #%d context", i);
 296            return;
 297        }
 298
 299        i++;
 300    }
 301}
 302
 303static void restore_context(WinDumpHeader64 *h,
 304                            struct saved_context *saved_ctx)
 305{
 306    int i;
 307    Error *err = NULL;
 308
 309    for (i = 0; i < h->NumberProcessors; i++) {
 310        if (cpu_memory_rw_debug(first_cpu, saved_ctx[i].addr,
 311                (uint8_t *)&saved_ctx[i].ctx, sizeof(WinContext), 1)) {
 312            error_setg(&err, "win-dump: failed to restore CPU #%d context", i);
 313            warn_report_err(err);
 314        }
 315    }
 316}
 317
 318void create_win_dump(DumpState *s, Error **errp)
 319{
 320    WinDumpHeader64 *h = (WinDumpHeader64 *)(s->guest_note +
 321            VMCOREINFO_ELF_NOTE_HDR_SIZE);
 322    X86CPU *first_x86_cpu = X86_CPU(first_cpu);
 323    uint64_t saved_cr3 = first_x86_cpu->env.cr[3];
 324    struct saved_context *saved_ctx = NULL;
 325    Error *local_err = NULL;
 326
 327    if (s->guest_note_size != sizeof(WinDumpHeader64) +
 328            VMCOREINFO_ELF_NOTE_HDR_SIZE) {
 329        error_setg(errp, "win-dump: invalid vmcoreinfo note size");
 330        return;
 331    }
 332
 333    check_header(h, &local_err);
 334    if (local_err) {
 335        error_propagate(errp, local_err);
 336        return;
 337    }
 338
 339    /*
 340     * Further access to kernel structures by virtual addresses
 341     * should be made from system context.
 342     */
 343
 344    first_x86_cpu->env.cr[3] = h->DirectoryTableBase;
 345
 346    check_kdbg(h, &local_err);
 347    if (local_err) {
 348        error_propagate(errp, local_err);
 349        goto out_cr3;
 350    }
 351
 352    patch_header(h);
 353
 354    saved_ctx = g_new(struct saved_context, h->NumberProcessors);
 355
 356    /*
 357     * Always patch context because there is no way
 358     * to determine if the system-saved context is valid
 359     */
 360
 361    patch_and_save_context(h, saved_ctx, &local_err);
 362    if (local_err) {
 363        error_propagate(errp, local_err);
 364        goto out_free;
 365    }
 366
 367    s->total_size = h->RequiredDumpSpace;
 368
 369    s->written_size = qemu_write_full(s->fd, h, sizeof(*h));
 370    if (s->written_size != sizeof(*h)) {
 371        error_setg(errp, QERR_IO_ERROR);
 372        goto out_restore;
 373    }
 374
 375    write_runs(s, h, &local_err);
 376    if (local_err) {
 377        error_propagate(errp, local_err);
 378        goto out_restore;
 379    }
 380
 381out_restore:
 382    restore_context(h, saved_ctx);
 383out_free:
 384    g_free(saved_ctx);
 385out_cr3:
 386    first_x86_cpu->env.cr[3] = saved_cr3;
 387
 388    return;
 389}
 390