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dump: add fallback KDBG using in Windows dump

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KdDebuggerDataBlock may be encrypted in guest memory and dump will be
useless in this case. But guest driver can obtain decrypted KDBG and
expose its address through BugcheckParameter1 field in raw header.
After this patch, QEMU will be able to use fallback KdDebuggerDataBlock.

Signed-off-by: Viktor Prutyanov <viktor.prutyanov@virtuozzo.com>
Message-Id: <20180517162342.4330-4-viktor.prutyanov@virtuozzo.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Viktor Prutyanov 2018-05-17 19:23:41 +03:00 committed by Paolo Bonzini
parent 92d1b3d508
commit 2ababfcc0e
1 changed files with 22 additions and 6 deletions
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28
win_dump.c
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@ -144,21 +144,37 @@ 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,
h->KdDebuggerDataBlock + KDBG_OWNER_TAG_OFFSET64,
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))) {
error_setg(errp, "win-dump: invalid KDBG OwnerTag,"
" expected '%.4s', got '%.4s',"
" KdDebuggerDataBlock seems to be encrypted",
OwnerTag, read_OwnerTag);
return;
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;
}
void create_win_dump(DumpState *s, Error **errp)