[Qemu-devel] QEMU does not communicate properly with GDB with a 64 bit guest

[Furukawa, Eiji]

When GDB is connected with qemu-1.1.0(target x86_64-softmmu), it is 
not possible to debug it. 
(Bug#640213)

The reason for the cause is that the correspondence of CPU register 
and the register value seen on the GDB side is incorrect. 

The evasion of the problem is possible by the replacement of the cpu_
gdb_read_register() of qeqemu-1.1.0/gdbstub.c with the cpu_gdb_
read_register() of qemu-0.10.6/gdbstub.c. 

What is the change intention of this source?


Qemu：qemu-1.1.0
GDB ：6.8-27.el5

- Qemu start option
./qemu-system-x86_64 -m 2048 hda.img -machine pc-1.0 -L ./pc-bios/ -monitor pty 
-s -S

- CPU register dump from Qemu console
(qemu) info registers
EAX=00007480 EBX=00000350 ECX=00000053 EDX=000001f0
ESI=000003f6 EDI=0000015a EBP=00074800 ESP=000002ec
EIP=0000e8f9 EFL=00000046 [---Z-P-] CPL=0 II=0 A20=1 
SMM=0 HLT=0 
ES =7480 00074800 0000ffff 00009300 
CS =f000 000f0000 0000ffff 00009e00 
SS =9f40 0009f400 0000ffff 00009300 
DS =9f40 0009f400 0000ffff 00009300 
FS =0000 00000000 0000ffff 00009300 
GS =0000 00000000 0000ffff 00009300
LDT=0000 00000000 0000ffff 00008200
TR =0000 00000000 0000ffff 00008b00
GDT=     00009090 00000027
IDT=     00000000 000003ff
 ::::
 

- CPU register dump from GDB
(gdb) info registers
eax            0x76a0   30368
ecx            0xe8f9   59641
edx            0x46     70
ebx            0xf000   61440
esp            0x9f40   0x9f40
ebp            0x9f40   0x9f40
esi            0x76a0   30368
edi            0x0      0
eip            0x0      0
eflags         0x0      [ ]
cs             0x0      0
ss             0x0      0
ds             0x0      0
es             0x0      0
fs             0x0      0
gs             0x0      0

--
E.Furukawa