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dump: use system context in Windows dump 

We use CPU  to access guest virtual memory, but it can execute user
thread at that moment. So, switch CR3 to PageDirectoryBase from header
and restore original value at the end.

Signed-off-by: Viktor Prutyanov <viktor.prutyanov@virtuozzo.com>
Message-Id: <20180517162342.4330-3-viktor.prutyanov@virtuozzo.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Viktor Prutyanov 2018-05-17 19:23:40 +03:00 committed by Paolo Bonzini
parent 2da91b54fe
commit 92d1b3d508
1 changed files with 17 additions and 9 deletions

26
win_dump.c
View File

@ -111,12 +111,6 @@ static void patch_header(WinDumpHeader64 *h)
h->PhysicalMemoryBlock.unused = 0;
h->unused1 = 0;
/*
* We assume h->DirectoryBase and current CR3 are the same when we access
* memory by virtual address. In other words, we suppose current context
* is system context. It is definetely true in case of BSOD.
*/
patch_mm_pfn_database(h, &local_err);
if (local_err) {
warn_report_err(local_err);
@ -171,6 +165,8 @@ 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];
Error *local_err = NULL;
if (s->guest_note_size != sizeof(WinDumpHeader64) +
@ -185,10 +181,17 @@ void create_win_dump(DumpState *s, Error **errp)
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);
return;
goto out_cr3;
}
patch_header(h);
@ -198,12 +201,17 @@ void create_win_dump(DumpState *s, Error **errp)
s->written_size = qemu_write_full(s->fd, h, sizeof(*h));
if (s->written_size != sizeof(*h)) {
error_setg(errp, QERR_IO_ERROR);
return;
goto out_cr3;
}
write_runs(s, h, &local_err);
if (local_err) {
error_propagate(errp, local_err);
return;
goto out_cr3;
}
out_cr3:
first_x86_cpu->env.cr[3] = saved_cr3;
return;
}