Re: [Qemu-devel] Re: qemu-ppc fails to run clone with CLONE_VM, threaded programs, non-static programs

[Mulyadi Santosa <a_mulyadi@softhome.net>]

Hello...

> I worked with pbrook on #qemu to debug this issue.  The problem turns
> out to be that qemu's do_fork function on PowerPC zeroes out r7-r31
> in the new CPU state structure after a clone, which it should not do,

Josh....at least it proves (to me) that the parameters passed to the 
clone() is correct. About the registers....well, this is completely new 
for me.

I wonder, what is the function of those registers (r7-r31)? Something 
related with the segments?

> as the child's registers should match the parent; it also does not
> zero register r3, which holds the return value and should be zero in
> the child.  I've prepared and attached a patch which should solve
> this problem.

Nice...this is something we surely forgot from out last attempt to debug 
the problem....return value. I was too focused on checking every memory 
accesses were done inside process address space and function address 
translation were done correctly :)

Anyway, just a personal suggestion. You can put that patch to 
qemu.dad-answers.com along with the description on how you found the 
bug and what this patch does.

regards

Mulyadi