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Debugging QEMU using gdb

Question asked by Manish Tiwari Employee on Jan 26, 2015
Latest reply on Jan 29, 2015 by Yiping Wang

Hello all,

 

I have launched QEMU on p4080 with below options:

 

root@p4080ds:~# qemu-system-ppc -s -S -enable-kvm -nographic  -m 512 -M ppce500 -cpu e500mc -kernel uImage -initrd rootfs.ext2.gz -append "root=/dev/ram rw console=ttyS0,115200"

 

But don't see kernel come up with it and in order to debug it further, I have attached gdb .

 

 

root@p4080ds:~# gdb vmlinux -ex 'target remote localhost:1234'

GNU gdb (GDB) 7.6.2

Copyright (C) 2013 Free Software Foundation, Inc.

License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>

This is free software: you are free to change and redistribute it.

There is NO WARRANTY, to the extent permitted by law.  Type "show copying"

and "show warranty" for details.

This GDB was configured as "powerpc-fsl-linux".

For bug reporting instructions, please see:

<http://www.gnu.org/software/gdb/bugs/>...

Reading symbols from /home/root/vmlinux...done.

Remote debugging using localhost:1234

0x00000000 in ?? ()

(gdb) b kvm_vcpu_ioctl

Breakpoint 1 at 0xc002ce60: file arch/powerpc/kvm/../../../virt/kvm/kvm_main.c, line 1963.

(gdb) p kvm_vcpu_ioctl

Cannot access memory at address 0xc002ce60

(gdb)

 

 

But I don't understand what "0x00000000 in ?? ()" &  "Cannot access memory at address 0xc002ce60" implies to?

 

Thanks,

Manish Tiwari.

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