qemu-system-ppc64 option -smp 2 broken with commit 20b6643324a79860dcdfe811ffe4a79942bca21e

[Anushree Mathur <anushree.mathur@linux.vnet.ibm.com>]

Hi everyone,

I was trying to boot rhel9.3 image with upstream qemu-system-ppc64 -smp 
2 option and observed a segfault (qemu crash).

qemu command line used:

qemu-system-ppc64 -name Rhel9.3.ppc64le -smp 2 -m 16G -vga none 
-nographic -machine pseries -cpu POWER10 -accel tcg -device 
virtio-scsi-pci -drive file=/home/rh93.qcow2,if=none,format=qcow2,id=hd0 
-device scsi-hd,drive=hd0 -boot c

After doing a git bisect, I found the first bad commit which introduced 
this issue is below:

[qemu]# git bisect good
20b6643324a79860dcdfe811ffe4a79942bca21e is the first bad commit
commit 20b6643324a79860dcdfe811ffe4a79942bca21e
Author: Richard Henderson <richard.henderson@linaro.org>
Date:   Mon Dec 5 17:45:02 2022 -0600

     tcg/ppc: Reorg goto_tb implementation

     The old ppc64 implementation replaces 2 or 4 insns, which leaves a race
     condition in which a thread could be stopped at a PC in the middle of
     the sequence, and when restarted does not see the complete address
     computation and branches to nowhere.

     The new implemetation replaces only one insn, swapping between

             b       <dest>
     and
             mtctr   r31

     falling through to a general-case indirect branch.

     Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
     Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

  tcg/ppc/tcg-target.c.inc | 152 
+++++++++++++----------------------------------
  tcg/ppc/tcg-target.h     |   3 +-
  2 files changed, 41 insertions(+), 114 deletions(-)
[qemu]#

Can someone please take a look and suggest a fix to resolve this issue?

Thanks in advance.
Regards,
Anushree-Mathur