Re: [Qemu-devel] [Qemu-ppc] [PATCH RFC 0/4] Enable MTTCG on PowerPC

[Programmingkid]

> On 09/02/2016 08:32 AM, Nikunj A Dadhania wrote:
>> The series is a first attempt at enabling Multi-Threaded TCG on PowerPC.
>> Changes that were needed to enable PowerPC are pretty simple;
>> 
>> Patch 01: Take a iothread lock during hcall, as hcall can generate io 
>> requests
>>      02: For TCG, we were harcoding smt as 1, this gets rid of the limitation
>>      03: Use atomic_cmpxchg in store conditional
>>      04: With more threads, flush the entry from each cpu. 
>>        This can be optimized further.
>> 
>> The patches are based on the Alex Bennee's base enabling patches for 
>> MTTCG[1] and Emilios's cmpxchg atomics. The consolidated tree of the 
>> above patches is here:
>> 
>> https://github.com/stsquad/qemu/tree/mttcg/base-patches-v4-with-cmpxchg-atomics-v2
>> 
>> Apart from the above, PPC patches are based out of ppc-for-2.8 and 
>> load/store consolidation patches [2]
>> 
>> Series with all dependent patches available here: 
>> https://github.com/nikunjad/qemu/tree/ppc_mttcg_v1
>> 
>> Testing: 
>> ========
>> 
>> -smp 4,cores=1,threads=4 -accel tcg,thread=multi
>> 
>> TODO
>> ====
>> Implement msgsndp instructions(door-bell), newer kernels enable it 
>> depending on the PVR. I have been using following workaround to boot.
>> https://github.com/nikunjad/qemu/commit/2c10052c5f93418a6b920e6ba3ce1813fcf50bc4
> 
> You could also introduce a Power8 DD1 in qemu. From the kernel cputable :
> 
>       {       /* Power8 DD1: Does not support doorbell IPIs */
>               .pvr_mask               = 0xffffff00,
>               .pvr_value              = 0x004d0100,
>               .cpu_name               = "POWER8 (raw)",
>               .cpu_features           = CPU_FTRS_POWER8_DD1,
>               ...
> 
> Cheers,
> C.

What I did:

git clone https://github.com/nikunjad/qemu/tree/ppc_mttcg_v1

git checkout ppc_mttcg_v1

./configure --target-list=ppc-softmmu,i386-softmmu --cxx=gcc-4.9 --cc=gcc-4.9 
--objcc=gcc-4.9 --disable-gtk --disable-sdl && make

After these steps I tried to test Windows XP and Windows 2000 using this 
command line:
./i386-softmmu/qemu-system-i386 -name 'Windows XP' -hda 'Windows XP Hard 
Drive.img' -boot c -smp 4,cores=1,threads=4 -accel tcg,thread=multi

This causes QEMU to crash. The cause is an abort trap. This is what I captured:

Thread 7 Crashed:
0   libSystem.B.dylib                   0x00007fff825559ce 
__semwait_signal_nocancel + 10
1   libSystem.B.dylib                   0x00007fff825558d0 nanosleep$NOCANCEL + 
129
2   libSystem.B.dylib                   0x00007fff825b23ce usleep$NOCANCEL + 57
3   libSystem.B.dylib                   0x00007fff825d1a00 abort + 93
4   qemu-system-i386                    0x0000000100036c65 
qemu_tcg_cpu_thread_fn + 325 (cpus.c:1384)
5   libSystem.B.dylib                   0x00007fff8251bfd6 _pthread_start + 331
6   libSystem.B.dylib                   0x00007fff8251be89 thread_start + 13

Trying Windows 2000 also causes the same crash.

I then tried Mac OS 10.4. The command line was:
./ppc-softmmu/qemu-system-ppc -smp 4,cores=1,threads=4 -M mac99 -m 512 -hda 
'Mac OS 10.4.0.qcow2' -boot c -prom-env boot-args=-v -localtime

The result was this error message:
qemu-system-ppc: Number of SMP CPUs requested (4) exceeds max CPUs supported by 
machine 'mac99' (1)

I then tried using https://github.com/stsquad/qemu.git. The errors I see is 
this:

qemu-system-i386: -accel: invalid option

qemu-system-ppc: Number of SMP CPUs requested (4) exceeds max CPUs supported by 
machine 'mac99' (1)

I used the same command lines as above.

My info:
Host operating system: Mac OS 10.6.8
GCC 4.9