On 2023/06/12 12:42, Viktor Prutyanov wrote:
Prcb may be set to 0 for some CPUs if the dump was taken before they
start. The dump may still contain valuable information for started CPUs
so don't abandon conversion in such a case.
Signed-off-by: Akihiko Odaki <akihiko.od...@daynix.com>
---
contrib/elf2dmp/main.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/contrib/elf2dmp/main.c b/contrib/elf2dmp/main.c
index d77b8f98f7..91c58e4424 100644
--- a/contrib/elf2dmp/main.c
+++ b/contrib/elf2dmp/main.c
@@ -312,6 +312,11 @@ static int fill_context(KDDEBUGGER_DATA64 *kdbg,
return 1;
}
+ if (!Prcb) {
+ eprintf("Context for CPU #%d is missing\n", i);
+ continue;
+ }
+
if (va_space_rw(vs, Prcb + kdbg->OffsetPrcbContext,
&Context, sizeof(Context), 0)) {
eprintf("Failed to read CPU #%d ContextFrame location\n", i);
--
2.40.1
Hi Akihiko,
How this fix can be tested?
It is a bit difficult to test it as you need to interrupt the very early
stage of boot. I applied the following change to TCG so that it stops
immediately after the first processor configures Prcb.
diff --git a/target/i386/tcg/sysemu/misc_helper.c
b/target/i386/tcg/sysemu/misc_helper.c
index e1528b7f80..f68eba9cac 100644
--- a/target/i386/tcg/sysemu/misc_helper.c
+++ b/target/i386/tcg/sysemu/misc_helper.c
@@ -25,6 +25,9 @@
#include "exec/address-spaces.h"
#include "exec/exec-all.h"
#include "tcg/helper-tcg.h"
+#include "exec/gdbstub.h"
+#include "hw/core/cpu.h"
+#include "sysemu/runstate.h"
void helper_outb(CPUX86State *env, uint32_t port, uint32_t data)
{
@@ -217,7 +220,10 @@ void helper_wrmsr(CPUX86State *env)
env->segs[R_FS].base = val;
break;
case MSR_GSBASE:
+ printf("%s: %" PRIx64 "\n", __func__, val);
env->segs[R_GS].base = val;
+ gdb_set_stop_cpu(current_cpu);
+ vm_stop(RUN_STATE_PAUSED);
break;
case MSR_KERNELGSBASE:
env->kernelgsbase = val;
NumberProcessors field is still set to qemu_elf.state_nr, how does WinDbg react
to this?
If Prcb for processor 1 is missing, WinDbg outputs: KiProcessorBlock[1]
is null.
You can still debug the started processors with no issue.
Regards,
Akihiko Odaki
Viktor
