Re: Issue of step by step debugging of OVMF SEC code in QEMU

["wang xiaofeng" <winggundum82@163.com>]

Hi  Andrew,
    THe problem is solved, after the SEC code switch to protected mode, gdb can work well now








At 2017-08-04 11:26:16, "wang xiaofeng" <winggundum82@163.com> wrote:

HI Andrew,
     How can I adjust the debugger to correct mode? Or I have to enable the debug after swtich to protected mode?








At 2017-08-04 10:57:16, "Andrew Fish" <afish@apple.com> wrote:
>The reset vector is 16-bit real mode, so you have the debugger in the wrong mode. The code should transition to 32 bit protected early in the flow.
>
>Sent from my iPhone
>
>> On Aug 3, 2017, at 7:47 PM, wang xiaofeng <winggundum82@163.com> wrote:
>> 
>> Hello,
>>       I am tring to add my own SEC code base on OVMF and run on QEMU. Since the code cannot run I need to step to step trace the assembly code .
>>      The hang point is very early before I can use either UDK or debug serial output. I tried to use gdb to connect to QEMU.I start gdb in another terminal, and issue the following commands:
>>  (gdb) set architecture i386:x86-64:intel
>>  (gdb) target remote localhost:1234
>>   It really stops at the bios first instruction at 0XFFFFFFF0. But gdb shows eip= 0xFFF0 and CS=0xF000(why it not be 0xfff0). After I trigger the command "display /i $pc"
>>   It shows the assembly code in 0xFFF0 instead of    0XFFFFFFF0, so the information is incorrect.
>>   Anyone knows how to corrently debug the SEC code ? Other debug tool is also ok.
>>   Thanks in advance!
>> 
>> 
>> 
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