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

["Michael S. Tsirkin" <mst@redhat.com>]

On Mon, Nov 08, 2021 at 02:05:42PM +0100, 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.
> 
> Signed-off-by: BALATON Zoltan <balaton@eik.bme.hu>


Paolo, could you weight in on whether we can fix it properly
in the memory core? I suspect it's not a good idea to switch
to native without adding a bunch of byteswaps all
over the place ...

> ---
>  hw/acpi/core.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/hw/acpi/core.c b/hw/acpi/core.c
> index 1e004d0078..543e4a7875 100644
> --- a/hw/acpi/core.c
> +++ b/hw/acpi/core.c
> @@ -461,7 +461,7 @@ static const MemoryRegionOps acpi_pm_evt_ops = {
>      .impl.min_access_size = 2,
>      .valid.min_access_size = 1,
>      .valid.max_access_size = 2,
> -    .endianness = DEVICE_LITTLE_ENDIAN,
> +    .endianness = DEVICE_NATIVE_ENDIAN,
>  };
>  
>  void acpi_pm1_evt_init(ACPIREGS *ar, acpi_update_sci_fn update_sci,
> @@ -531,7 +531,7 @@ static const MemoryRegionOps acpi_pm_tmr_ops = {
>      .impl.min_access_size = 4,
>      .valid.min_access_size = 1,
>      .valid.max_access_size = 4,
> -    .endianness = DEVICE_LITTLE_ENDIAN,
> +    .endianness = DEVICE_NATIVE_ENDIAN,
>  };
>  
>  void acpi_pm_tmr_init(ACPIREGS *ar, acpi_update_sci_fn update_sci,
> @@ -608,7 +608,7 @@ static const MemoryRegionOps acpi_pm_cnt_ops = {
>      .impl.min_access_size = 2,
>      .valid.min_access_size = 1,
>      .valid.max_access_size = 2,
> -    .endianness = DEVICE_LITTLE_ENDIAN,
> +    .endianness = DEVICE_NATIVE_ENDIAN,
>  };
>  
>  void acpi_pm1_cnt_init(ACPIREGS *ar, MemoryRegion *parent,
> -- 
> 2.30.2