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qemu/win_dump.c
Viktor Prutyanov 2ad9b50f71 dump: add Windows live system dump 
Unlike dying Windows, live system memory doesn't contain
correct register contexts. But they can be populated with QEMU register
values.
After this patch, QEMU will be able to produce guest Windows live system
dump.

Signed-off-by: Viktor Prutyanov <viktor.prutyanov@virtuozzo.com>
Message-Id: <20180517162342.4330-5-viktor.prutyanov@virtuozzo.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2018-06-29 13:02:50 +02:00

385 lines
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/*
* Windows crashdump
*
* Copyright (c) 2018 Virtuozzo International GmbH
*
* This work is licensed under the terms of the GNU GPL, version 2 or later.
* See the COPYING file in the top-level directory.
*
*/
#include "qemu/osdep.h"
#include "qemu/cutils.h"
#include "elf.h"
#include "cpu.h"
#include "exec/hwaddr.h"
#include "monitor/monitor.h"
#include "sysemu/kvm.h"
#include "sysemu/dump.h"
#include "sysemu/sysemu.h"
#include "sysemu/memory_mapping.h"
#include "sysemu/cpus.h"
#include "qapi/error.h"
#include "qapi/qmp/qerror.h"
#include "qemu/error-report.h"
#include "hw/misc/vmcoreinfo.h"
#include "win_dump.h"
static size_t write_run(WinDumpPhyMemRun64 *run, int fd, Error **errp)
{
void *buf;
uint64_t addr = run->BasePage << TARGET_PAGE_BITS;
uint64_t size = run->PageCount << TARGET_PAGE_BITS;
uint64_t len = size;
buf = cpu_physical_memory_map(addr, &len, false);
if (!buf) {
error_setg(errp, "win-dump: failed to map run");
return 0;
}
if (len != size) {
error_setg(errp, "win-dump: failed to map entire run");
len = 0;
goto out_unmap;
}
len = qemu_write_full(fd, buf, len);
if (len != size) {
error_setg(errp, QERR_IO_ERROR);
}
out_unmap:
cpu_physical_memory_unmap(buf, addr, false, len);
return len;
}
static void write_runs(DumpState *s, WinDumpHeader64 *h, Error **errp)
{
WinDumpPhyMemDesc64 *desc = &h->PhysicalMemoryBlock;
WinDumpPhyMemRun64 *run = desc->Run;
Error *local_err = NULL;
int i;
for (i = 0; i < desc->NumberOfRuns; i++) {
s->written_size += write_run(run + i, s->fd, &local_err);
if (local_err) {
error_propagate(errp, local_err);
return;
}
}
}
static void patch_mm_pfn_database(WinDumpHeader64 *h, Error **errp)
{
if (cpu_memory_rw_debug(first_cpu,
h->KdDebuggerDataBlock + KDBG_MM_PFN_DATABASE_OFFSET64,
(uint8_t *)&h->PfnDatabase, sizeof(h->PfnDatabase), 0)) {
error_setg(errp, "win-dump: failed to read MmPfnDatabase");
return;
}
}
static void patch_bugcheck_data(WinDumpHeader64 *h, Error **errp)
{
uint64_t KiBugcheckData;
if (cpu_memory_rw_debug(first_cpu,
h->KdDebuggerDataBlock + KDBG_KI_BUGCHECK_DATA_OFFSET64,
(uint8_t *)&KiBugcheckData, sizeof(KiBugcheckData), 0)) {
error_setg(errp, "win-dump: failed to read KiBugcheckData");
return;
}
if (cpu_memory_rw_debug(first_cpu,
KiBugcheckData,
h->BugcheckData, sizeof(h->BugcheckData), 0)) {
error_setg(errp, "win-dump: failed to read bugcheck data");
return;
}
/*
* If BugcheckCode wasn't saved, we consider guest OS as alive.
*/
if (!h->BugcheckCode) {
h->BugcheckCode = LIVE_SYSTEM_DUMP;
}
}
/*
* This routine tries to correct mistakes in crashdump header.
*/
static void patch_header(WinDumpHeader64 *h)
{
Error *local_err = NULL;
h->RequiredDumpSpace = sizeof(WinDumpHeader64) +
(h->PhysicalMemoryBlock.NumberOfPages << TARGET_PAGE_BITS);
h->PhysicalMemoryBlock.unused = 0;
h->unused1 = 0;
patch_mm_pfn_database(h, &local_err);
if (local_err) {
warn_report_err(local_err);
local_err = NULL;
}
patch_bugcheck_data(h, &local_err);
if (local_err) {
warn_report_err(local_err);
}
}
static void check_header(WinDumpHeader64 *h, Error **errp)
{
const char Signature[] = "PAGE";
const char ValidDump[] = "DU64";
if (memcmp(h->Signature, Signature, sizeof(h->Signature))) {
error_setg(errp, "win-dump: invalid header, expected '%.4s',"
" got '%.4s'", Signature, h->Signature);
return;
}
if (memcmp(h->ValidDump, ValidDump, sizeof(h->ValidDump))) {
error_setg(errp, "win-dump: invalid header, expected '%.4s',"
" got '%.4s'", ValidDump, h->ValidDump);
return;
}
}
static void check_kdbg(WinDumpHeader64 *h, Error **errp)
{
const char OwnerTag[] = "KDBG";
char read_OwnerTag[4];
uint64_t KdDebuggerDataBlock = h->KdDebuggerDataBlock;
bool try_fallback = true;
try_again:
if (cpu_memory_rw_debug(first_cpu,
KdDebuggerDataBlock + KDBG_OWNER_TAG_OFFSET64,
(uint8_t *)&read_OwnerTag, sizeof(read_OwnerTag), 0)) {
error_setg(errp, "win-dump: failed to read OwnerTag");
return;
}
if (memcmp(read_OwnerTag, OwnerTag, sizeof(read_OwnerTag))) {
if (try_fallback) {
/*
* If attempt to use original KDBG failed
* (most likely because of its encryption),
* we try to use KDBG obtained by guest driver.
*/
KdDebuggerDataBlock = h->BugcheckParameter1;
try_fallback = false;
goto try_again;
} else {
error_setg(errp, "win-dump: invalid KDBG OwnerTag,"
" expected '%.4s', got '%.4s'",
OwnerTag, read_OwnerTag);
return;
}
}
h->KdDebuggerDataBlock = KdDebuggerDataBlock;
}
struct saved_context {
WinContext ctx;
uint64_t addr;
};
static void patch_and_save_context(WinDumpHeader64 *h,
struct saved_context *saved_ctx,
Error **errp)
{
uint64_t KiProcessorBlock;
uint16_t OffsetPrcbContext;
CPUState *cpu;
int i = 0;
if (cpu_memory_rw_debug(first_cpu,
h->KdDebuggerDataBlock + KDBG_KI_PROCESSOR_BLOCK_OFFSET64,
(uint8_t *)&KiProcessorBlock, sizeof(KiProcessorBlock), 0)) {
error_setg(errp, "win-dump: failed to read KiProcessorBlock");
return;
}
if (cpu_memory_rw_debug(first_cpu,
h->KdDebuggerDataBlock + KDBG_OFFSET_PRCB_CONTEXT_OFFSET64,
(uint8_t *)&OffsetPrcbContext, sizeof(OffsetPrcbContext), 0)) {
error_setg(errp, "win-dump: failed to read OffsetPrcbContext");
return;
}
CPU_FOREACH(cpu) {
X86CPU *x86_cpu = X86_CPU(cpu);
CPUX86State *env = &x86_cpu->env;
uint64_t Prcb;
uint64_t Context;
WinContext ctx;
if (cpu_memory_rw_debug(first_cpu,
KiProcessorBlock + i * sizeof(uint64_t),
(uint8_t *)&Prcb, sizeof(Prcb), 0)) {
error_setg(errp, "win-dump: failed to read"
" CPU #%d PRCB location", i);
return;
}
if (cpu_memory_rw_debug(first_cpu,
Prcb + OffsetPrcbContext,
(uint8_t *)&Context, sizeof(Context), 0)) {
error_setg(errp, "win-dump: failed to read"
" CPU #%d ContextFrame location", i);
return;
}
saved_ctx[i].addr = Context;
ctx = (WinContext){
.ContextFlags = WIN_CTX_ALL,
.MxCsr = env->mxcsr,
.SegEs = env->segs[0].selector,
.SegCs = env->segs[1].selector,
.SegSs = env->segs[2].selector,
.SegDs = env->segs[3].selector,
.SegFs = env->segs[4].selector,
.SegGs = env->segs[5].selector,
.EFlags = cpu_compute_eflags(env),
.Dr0 = env->dr[0],
.Dr1 = env->dr[1],
.Dr2 = env->dr[2],
.Dr3 = env->dr[3],
.Dr6 = env->dr[6],
.Dr7 = env->dr[7],
.Rax = env->regs[R_EAX],
.Rbx = env->regs[R_EBX],
.Rcx = env->regs[R_ECX],
.Rdx = env->regs[R_EDX],
.Rsp = env->regs[R_ESP],
.Rbp = env->regs[R_EBP],
.Rsi = env->regs[R_ESI],
.Rdi = env->regs[R_EDI],
.R8 = env->regs[8],
.R9 = env->regs[9],
.R10 = env->regs[10],
.R11 = env->regs[11],
.R12 = env->regs[12],
.R13 = env->regs[13],
.R14 = env->regs[14],
.R15 = env->regs[15],
.Rip = env->eip,
.FltSave = {
.MxCsr = env->mxcsr,
},
};
if (cpu_memory_rw_debug(first_cpu, Context,
(uint8_t *)&saved_ctx[i].ctx, sizeof(WinContext), 0)) {
error_setg(errp, "win-dump: failed to save CPU #%d context", i);
return;
}
if (cpu_memory_rw_debug(first_cpu, Context,
(uint8_t *)&ctx, sizeof(WinContext), 1)) {
error_setg(errp, "win-dump: failed to write CPU #%d context", i);
return;
}
i++;
}
}
static void restore_context(WinDumpHeader64 *h,
struct saved_context *saved_ctx)
{
int i;
Error *err = NULL;
for (i = 0; i < h->NumberProcessors; i++) {
if (cpu_memory_rw_debug(first_cpu, saved_ctx[i].addr,
(uint8_t *)&saved_ctx[i].ctx, sizeof(WinContext), 1)) {
error_setg(&err, "win-dump: failed to restore CPU #%d context", i);
warn_report_err(err);
}
}
}
void create_win_dump(DumpState *s, Error **errp)
{
WinDumpHeader64 *h = (WinDumpHeader64 *)(s->guest_note +
VMCOREINFO_ELF_NOTE_HDR_SIZE);
X86CPU *first_x86_cpu = X86_CPU(first_cpu);
uint64_t saved_cr3 = first_x86_cpu->env.cr[3];
struct saved_context *saved_ctx = NULL;
Error *local_err = NULL;
if (s->guest_note_size != sizeof(WinDumpHeader64) +
VMCOREINFO_ELF_NOTE_HDR_SIZE) {
error_setg(errp, "win-dump: invalid vmcoreinfo note size");
return;
}
check_header(h, &local_err);
if (local_err) {
error_propagate(errp, local_err);
return;
}
/*
* Further access to kernel structures by virtual addresses
* should be made from system context.
*/
first_x86_cpu->env.cr[3] = h->DirectoryTableBase;
check_kdbg(h, &local_err);
if (local_err) {
error_propagate(errp, local_err);
goto out_cr3;
}
patch_header(h);
saved_ctx = g_new(struct saved_context, h->NumberProcessors);
/*
* Always patch context because there is no way
* to determine if the system-saved context is valid
*/
patch_and_save_context(h, saved_ctx, &local_err);
if (local_err) {
error_propagate(errp, local_err);
goto out_free;
}
s->total_size = h->RequiredDumpSpace;
s->written_size = qemu_write_full(s->fd, h, sizeof(*h));
if (s->written_size != sizeof(*h)) {
error_setg(errp, QERR_IO_ERROR);
goto out_restore;
}
write_runs(s, h, &local_err);
if (local_err) {
error_propagate(errp, local_err);
goto out_restore;
}
out_restore:
restore_context(h, saved_ctx);
out_free:
g_free(saved_ctx);
out_cr3:
first_x86_cpu->env.cr[3] = saved_cr3;
return;
}
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