Re: [PATCH] hw/acpi: Set memory regions to native endian as a work around

[BALATON Zoltan <balaton@eik.bme.hu>]

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On Mon, 8 Nov 2021, BALATON Zoltan wrote:
> On Mon, 8 Nov 2021, Paolo Bonzini wrote:
>> On 11/8/21 15:30, Paolo Bonzini wrote:
>>> On 11/8/21 14:05, BALATON Zoltan wrote:
>>>> When using ACPI on big endian machine (such as ppc/pegasos2 which has
>>>> a VT8231 south bridge with ACPI) writes to ACPI registers come out
>>>> byte swapped. This may be caused by a bug in memory subsystem but
>>>> until that is fixed setting the ACPI memory regions to native endian
>>>> makes it usable for big endian machines. This fixes ACPI shutdown with
>>>> pegasos2 when using the board firmware for now.
>>>> This could be reverted when the memory layer is fixed.
>>> 
>>> What is the path to the swapped writes?  Even just a backtrace might be 
>>> enough to understand what's going on, and especially where the bug is.
>> 
>> Ok, Michael pointed me at 
>> https://lore.kernel.org/all/20211011080528-mutt-send-email-mst@kernel.org/.

Ping? I haven't seen an alternative fix yet. If you don't have time now 
this could be postponed to next version with the native endian work around 
for now.

Regards,
BALATON Zoltan

> I was about to say that here's the original thread:
>
> https://lists.nongnu.org/archive/html/qemu-devel/2021-10/msg01972.html
>
> and here's the backtrace:
>
> #0  acpi_pm1_cnt_write (val=40, ar=0x55555695f340) at ../hw/acpi/core.c:556
> #1  acpi_pm_cnt_write (opaque=0x55555695f340, addr=1, val=40, width=2) at 
> ../hw/acpi/core.c:602
> #2  0x0000555555b3a82f in memory_region_write_accessor
>    (mr=mr@entry=0x55555695f590, addr=1, value=value@entry=0x7fffefffdd08, 
> size=size@entry=2, shift=<optimized out>, mask=mask@entry=65535, attrs=...)
>    at ../softmmu/memory.c:492
> #3  0x0000555555b3813e in access_with_adjusted_size
>    (addr=addr@entry=1, value=value@entry=0x7fffefffdd08, size=size@entry=1, 
> access_size_min=<optimized out>, access_size_max=<optimized out>, access_fn=
>    0x555555b3a7b0 <memory_region_write_accessor>, mr=0x55555695f590, 
> attrs=...) at ../softmmu/memory.c:554
> #4  0x0000555555b3c449 in memory_region_dispatch_write 
> (mr=mr@entry=0x55555695f590, addr=1, data=<optimized out>, op=<optimized 
> out>, attrs=attrs@entry=...)
>    at ../softmmu/memory.c:1511
> #5  0x0000555555b2c121 in flatview_write_continue
>    (fv=fv@entry=0x7fff84d23b30, addr=addr@entry=4261416709, 
> attrs=attrs@entry=..., ptr=ptr@entry=0x7fffefffdec0, len=len@entry=1, 
> addr1=<optimized out>,
>     l=<optimized out>, mr=0x55555695f590) at host-utils.h:165
> #6  0x0000555555b2c399 in flatview_write (len=1, buf=0x7fffefffdec0, 
> attrs=..., addr=4261416709, fv=0x7fff84d23b30) at ../softmmu/physmem.c:2822
> #7  subpage_write (opaque=<optimized out>, addr=<optimized out>, 
> value=<optimized out>, len=1, attrs=...) at ../softmmu/physmem.c:2488
> #8  0x0000555555b380de in access_with_adjusted_size
>    (addr=addr@entry=3845, value=value@entry=0x7fffefffdf88, 
> size=size@entry=1, access_size_min=<optimized out>, 
> access_size_max=<optimized out>, access_fn=
>    0x555555b3aa80 <memory_region_write_with_attrs_accessor>, 
> mr=0x7fff84710bb0, attrs=...) at ../softmmu/memory.c:549
> #9  0x0000555555b3c449 in memory_region_dispatch_write 
> (mr=mr@entry=0x7fff84710bb0, addr=addr@entry=3845, data=<optimized out>, 
> data@entry=40, op=op@entry=MO_8, attrs=...)
>    at ../softmmu/memory.c:1511
> #10 0x0000555555c07b4c in io_writex
>    (env=env@entry=0x55555666a820, 
> iotlbentry=iotlbentry@entry=0x7fff843367f0, mmu_idx=1, val=val@entry=40, 
> addr=addr@entry=4261416709,
>     retaddr=retaddr@entry=140736116523268, op=MO_8) at 
> ../accel/tcg/cputlb.c:1420
> #11 0x0000555555c0b5df in store_helper (op=MO_8, retaddr=<optimized out>, 
> oi=<optimized out>, val=40, addr=4261416709, env=0x55555666a820) at 
> ../accel/tcg/cputlb.c:2355
> #12 full_stb_mmu (env=0x55555666a820, addr=4261416709, val=40, oi=<optimized 
> out>, retaddr=140736116523268) at ../accel/tcg/cputlb.c:2404
> #13 0x00007fffae3b8104 in code_gen_buffer ()
> #14 0x0000555555bfcfab in cpu_tb_exec (cpu=cpu@entry=0x555556661360, 
> itb=itb@entry=0x7fffae3b7fc0 <code_gen_buffer+56197011>, 
> tb_exit=tb_exit@entry=0x7fffefffe668)
>    at ../accel/tcg/cpu-exec.c:357
> #15 0x0000555555bfe089 in cpu_loop_exec_tb (tb_exit=0x7fffefffe668, 
> last_tb=<synthetic pointer>, tb=0x7fffae3b7fc0 <code_gen_buffer+56197011>, 
> cpu=0x555556661360)
>    at ../accel/tcg/cpu-exec.c:833
> #16 cpu_exec (cpu=cpu@entry=0x555556661360) at ../accel/tcg/cpu-exec.c:992
> #17 0x0000555555c1bba0 in tcg_cpus_exec (cpu=cpu@entry=0x555556661360) at 
> ../accel/tcg/tcg-accel-ops.c:67
> #18 0x0000555555c1c3d7 in rr_cpu_thread_fn (arg=arg@entry=0x555556661360) at 
> ../accel/tcg/tcg-accel-ops-rr.c:214
> #19 0x0000555555d5c049 in qemu_thread_start (args=0x7fffefffe750) at 
> ../util/qemu-thread-posix.c:556
> #20 0x00007ffff6a95dea in start_thread () at /lib64/libpthread.so.0
> #21 0x00007ffff69c8fdf in clone () at /lib64/libc.so.6
>