[Qemu-devel] Possible ppc64le regression in master?

[Andrew Randrianasulu]

Hello again.

I was trying to set up virtual ppc64le machine with some linux inside. First 
tried with qemu-3.1 on 32-bit host. It worked, but was slow-ish.

next I tred to compile latest qemu git (up to commit 
8eb29f1bf5a974dc4c11d2d1f5e7c7f7a62be116) on 64-bit Slackware, to get MTTCG 
acceleration.

qemu was successfully compiled with those CFLAGS:


CFLAGS=-O2 -U_FORTIFY_SOURCE -D_FORTIFY_SOURCE=2 -g -O3 -march=native 
-mtune=native -Wno-maybe-uninitialized

but then when I tried to run it - console was fine, but X inside Alpine Linux 
was all striped!

Going back to 2.12+ compiled last year fixed this issue to me, X is back to 
normal.

I was using this guide:
https://buggy.link/2018/01/31/ppc64le-on-x86_64-qemu-full-system-emulation.html

Command lines tried:

address@hidden:~/src/qemu# ppc64-softmmu/qemu-system-ppc64 -m 1024 -display 
sdl,gl=on -smp 3 -hda /mnt/alpine_disk.img -> corruption in X, console ok.

ppc64-softmmu/qemu-system-ppc64 -m 1024 -display sdl,gl=on -vga virtio -smp 3 
-M 
pseries-3.1 -hda /mnt/alpine_disk.img -> even console is blue!

address@hidden:~/src/qemu# ppc64-softmmu/qemu-system-ppc64 -m 1024 -display 
sdl,gl=on -vga cirrus -smp 1 -M pseries-3.1 -hda /mnt/alpine_disk.img -> same 
blue screen even on console

address@hidden:~/src/qemu# ppc64-softmmu/qemu-system-ppc64 -m 1024 -smp 4 -M 
pseries-3.1 -hda /mnt/alpine_disk.img - this defaulted to gtk UI, and  X was 
corrupted anyway :/

address@hidden:~/src/qemu# ppc64-softmmu/qemu-system-ppc64 -m 1024 -display 
sdl,gl=on -smp 1 -M pseries-3.1 -hda /mnt/alpine_disk.img -g 1024x768x32 - nice 
big console with correct colors, but X still corrupt!

address@hidden:~/src/qemu# qemu-system-ppc64 -m 1024 -display sdl,gl=on -smp 
3  -hda /mnt/alpine_disk.img -g 1024x768x32 -> old qemu still works OK, booted 
right now and compiling stuff.

Attached are files I modified on Alpine install - custom xorg.conf, .xinitrc 
and 
ash_history (so you can install same set of packages as I)

My host CPU is:
cat /proc/cpuinfo
processor       : 0
vendor_id       : AuthenticAMD
cpu family      : 21
model           : 2
model name      : AMD FX(tm)-4300 Quad-Core Processor
stepping        : 0
microcode       : 0x6000852
cpu MHz         : 3222.725
cache size      : 2048 KB
physical id     : 0
siblings        : 4
core id         : 0
cpu cores       : 2
apicid          : 16
initial apicid  : 0
fpu             : yes
fpu_exception   : yes
cpuid level     : 13
wp              : yes
flags           : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov 
pat pse36 clflush mmx fxsr sse sse2 ht syscall nx mmxext fxsr_opt pdpe1gb 
rdtscp lm constant_tsc rep_good nopl nonstop_tsc cpuid extd_apicid aperfmperf 
pni pclmulqdq monitor ssse3 fma cx16 sse4_1 sse4_2 popcnt aes xsave avx f16c 
lahf_lm cmp_legacy svm extapic cr8_legacy abm sse4a misalignsse 3dnowprefetch 
osvw ibs xop skinit wdt lwp fma4 tce nodeid_msr tbm topoext perfctr_core 
perfctr_nb cpb hw_pstate ssbd vmmcall bmi1 arat npt lbrv svm_lock nrip_save 
tsc_scale vmcb_clean flushbyasid decodeassists pausefilter pfthreshold
bugs            : fxsave_leak sysret_ss_attrs null_seg spectre_v1 spectre_v2 
spec_store_bypass
bogomips        : 7599.87
TLB size        : 1536 4K pages
clflush size    : 64
cache_alignment : 64
address sizes   : 48 bits physical, 48 bits virtual
power management: ts ttp tm 100mhzsteps hwpstate cpb eff_freq_ro

so, with avx.

I'll try to recompile with less agressive optimizations, and if this will not 
help - bisect .

Thanks for attention.

.ash_history
Description: Text document

.xinitrc
Description: Text document

xorg.conf
Description: Text document